Patent Publication Number: US-11034411-B2

Title: Bicycle controller

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 15/660,575, which was filed on filed on Jul. 26, 2017. This application claims priority to Japanese Patent Application No. 2016-149752, filed on Jul. 29, 2016, and Japanese Patent Application No. 2017-129061, filed on Jun. 30, 2017. The entire disclosures of Japanese Patent Application No. 2016-149752 and Japanese Patent Application No. 2017-129061 are hereby incorporated herein by reference. Also the entire disclosure of U.S. patent application Ser. No. 15/660,575 is hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present invention generally relates to a bicycle controller. 
     Background Information 
     Japanese Patent No. 5575968 (Patent document 1) discloses a bicycle controller that changes the speed at which an output of a motor responds to a change in manual driving force. In a case in which the manual driving force decreases, the bicycle controller changes the response speed of the motor output in accordance with a crank rotation speed. 
     SUMMARY 
     There is a demand for a bicycle controller that is configured to control the motor in a suitable manner even if the riding environment of the bicycle changes. It is an object of the present invention to provide a bicycle controller that is configured to control a motor in accordance with the riding environment of a bicycle. 
     In accordance with a first aspect of the present disclosure, a bicycle controller includes an electronic control unit that is configured to control a motor that assists in propulsion of a bicycle in accordance with a manual driving force. The electronic control unit is further configured to sets a response speed of the motor with respect to a change in the manual driving force for a case in which a vehicle speed of the bicycle is less than or equal to a first speed to be different from the response speed for a case in which the vehicle speed of the bicycle exceeds the first speed. 
     With the bicycle controller according to the first aspect, the motor can be controlled with a response speed suitable for a case in which the vehicle speed of the bicycle is less than or equal to a first speed and for a case in which the vehicle speed of the bicycle exceeds the first speed. 
     In accordance with a second aspect of the present disclosure, the bicycle controller according to the first aspect is configured so that the electronic control unit is further configured to set the response speed with respect to the change in the manual driving force for the case in which the vehicle speed of the bicycle is less than or equal to the first speed to be higher than the response speed for the case in which the vehicle speed of the bicycle exceeds the first speed. 
     With the bicycle controller according to the second aspect, the output of the motor can be quickly increased if the output of the motor is increased in a case in which the vehicle speed of the bicycle is less than or equal to the first speed. 
     In accordance with a third aspect of the present disclosure, the bicycle controller according to the first or second aspect is configured so that the electronic control unit is further configured to set the response speed with respect to the change in the manual driving force for the case in which the vehicle speed of the bicycle is less than or equal to the first speed to be lower than the response speed for the case in which the vehicle speed of the bicycle exceeds the first speed. 
     In accordance with a fourth aspect of the present disclosure, the bicycle controller according to any one of the first to third aspects is configured so that the electronic control unit is further configured to set the response speed to be different for a case in which the manual driving force increases from a case in which the manual driving force decreases. 
     In accordance with a fifth aspect of the present disclosure, the bicycle controller according to the fourth aspect is configured so that the electronic control unit is further configured to increase the response speed for a case in which the bicycle is less than or equal to the first speed and in which the manual driving force increases. 
     In accordance with a sixth aspect of the present disclosure, the bicycle controller according to any one of the first to fifth aspects is configured so that the electronic control unit is further configured to decrease the response speed in for case in which the bicycle is less than or equal to the first speed and in which the manual driving force decreases. 
     In accordance with a seventh aspect of the present disclosure, the bicycle controller according to the sixth aspect is configured so that the electronic control unit is further configured to increase the response speed for the case in which the bicycle is less than or equal to the first speed and in which the manual driving force increases. 
     In accordance with an eighth aspect of the present disclosure, the bicycle controller according to any one of the first to seventh aspects is configured so that the first speed is set in a range from 1 to 10 km/h. 
     In accordance with a ninth aspect of the present disclosure, the bicycle controller according to any one of the first to eighth aspects is configured so that the electronic control unit is further configured to reset the response speed of the motor to an original response speed upon determining the vehicle speed of the bicycle exceeds the first speed after the response speed of the motor was changed from the original response speed to a different response speed as a result of a determination that the vehicle speed of the bicycle was less than or equal to the first speed. 
     In accordance with a tenth aspect of the present disclosure, the bicycle controller according to any one of the first to ninth aspects is configured so that the electronic control unit is further configured to change the response speed of the motor with respect to the change in the manual driving force in accordance with an inclination angle of the bicycle. 
     In accordance with an eleventh aspect of the present disclosure, the bicycle controller according to the first aspect is configured so that the electronic control unit is further configured to decrease the response speed in a case in which the inclination angle of the bicycle increases on an uphill and in which the manual driving force decreases. 
     In accordance with a twelfth aspect of the present disclosure, the bicycle controller according to any one of the tenth or eleventh aspect is configured so that the electronic control unit is further configured to increase the response speed in a case in which the inclination angle of the bicycle increases on an uphill and in which the manual driving force increases. 
     In accordance with a thirteenth aspect of the present disclosure, the bicycle controller according to any one of the tenth to twelfth aspects is configured so that the electronic control unit is further configured to decrease the response speed in a case in which the inclination angle of the bicycle increases on a downhill and in which the manual driving force increases. 
     In accordance with a fourteenth aspect of the present disclosure, the bicycle controller according to any one of the tenth to thirteenth aspects further comprises an inclination detector that detects the inclination angle of the bicycle. 
     In accordance with a fifteenth aspect of the present disclosure, the bicycle controller according to any one of the tenth to fourteenth aspects is configured so that the electronic control unit is further configured to compute the inclination angle based on the manual driving force and a rotation speed of a crank of the bicycle. 
     According, the bicycle controller according to the present disclosure is configured to control a motor in accordance with the riding environment of a bicycle. Also, other objects, features, aspects and advantages of the disclosed bicycle controller will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the bicycle controller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the attached drawings which form a part of this original disclosure. 
         FIG. 1  is a block diagram in accordance with an electrical configuration of a bicycle including a bicycle controller in accordance with a first embodiment. 
         FIG. 2  is a flowchart of a motor control executed by an electronic control unit shown in  FIG. 1 . 
         FIG. 3  is a graph in accordance with the relationship of a time constant and a crank rotation speed with respect to an inclination angle in a first mode set by the electronic control unit shown in  FIG. 1 . 
         FIG. 4  is a graph in accordance with the relationship of the time constant and the crank rotation speed with respect to the inclination angle in a second mode set by the electronic control unit shown in  FIG. 1 . 
         FIG. 5  is a series of timing charts in accordance with one example of the motor control in the first mode. 
         FIG. 6  is a series of timing charts in accordance with one example of the motor control in the second mode. 
         FIG. 7  is a flowchart of a motor control executed by the electronic control unit in accordance with a second embodiment. 
         FIG. 8  is a series of timing charts in accordance with one example of the motor control in a first mode of the second embodiment. 
         FIG. 9  is a series of timing charts in accordance with one example of the motor control in a second mode of the second embodiment. 
         FIG. 10  is a first flowchart of a motor control executed by the electronic control unit in accordance with a third embodiment. 
         FIG. 11  is a second flowchart of the motor control executed by the electronic control unit in accordance with the third embodiment. 
         FIG. 12  is a graph in accordance with the relationship of a first torque and the rotation speed of a crank set by the electronic control unit in accordance with a fourth embodiment. 
         FIG. 13  is a flowchart of a motor control executed by the electronic control unit in accordance with the fourth embodiment. 
         FIG. 14  is a first flowchart of a motor control executed by the electronic control unit in accordance with a fifth embodiment. 
         FIG. 15  is a second flowchart of the motor control executed by the electronic control unit in accordance with the fifth embodiment. 
         FIG. 16  is a timing chart in accordance with one example of the motor control in accordance with the fifth embodiment. 
         FIG. 17  is a flowchart of a motor control executed by the electronic control unit in accordance with a sixth embodiment. 
         FIG. 18  is a flowchart of a motor control executed by the electronic control unit in accordance with a seventh embodiment. 
         FIG. 19  is a flowchart in accordance with a first modified example of the motor control. 
         FIG. 20  is a flowchart in accordance with a second modified example of the motor control. 
         FIG. 21  is a flowchart in accordance with a third modified example of the motor control. 
         FIG. 22  is a flowchart in accordance with a fourth modified example of the motor control. 
         FIG. 23  is a flowchart in accordance with a fifth modified example of the motor control. 
         FIG. 24  is a flowchart in accordance with a sixth modified example of the motor control. 
         FIG. 25  is a flowchart in accordance with a seventh modified example of the motor control. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Selected embodiments will now be explained with reference to the drawings. It will be apparent to those skilled in the bicycle field from this disclosure that the following descriptions of the embodiments are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
     A bicycle  10  including one embodiment of a bicycle controller will now be described with reference to  FIG. 1 . The bicycle  10  includes a drive mechanism  12 , an operation unit  14 , a battery  16 , an assist device  18  and a bicycle controller  30 . The bicycle  10  is, for example, a mountain bike but can be a road bike or a city bike. 
     The drive mechanism  12  includes a crank  12 A and a pair of pedals  12 D. The crank  12 A includes a crankshaft  12 B and a pair of crank arms  12 C. The drive mechanism  12  transmits a manual driving force, which is applied to the pedals  12 D by a rider to rotate a rear wheel (not shown). The drive mechanism  12  is configured to transmit the rotation of the crank through, for example, a chain, a belt or a shaft (none shown). The drive mechanism  12  includes a front rotating body (not shown) that is connected to the crankshaft  12 B by a one-way clutch (not shown). The one-way clutch is configured to rotate the front rotating body forward in a case in which the crank  12 A is rotated forward. The one-way clutch is configured to restrict rearward rotation of the front rotating body in a case in which the crank  12 A is rotated rearward. The front rotating body includes a sprocket, a pulley, or a bevel gear (none shown). The front rotating body can be connected to the crankshaft  12 B without the one-way clutch. 
     The operation unit  14  is provided on the bicycle  10 . The operation unit  14  is configured to communicate with an electronic control unit  32  of the bicycle controller  30  through a wired connection or a wireless connection. The operation unit  14  includes, for example, an operation member, a sensor that detects movement of the operation member, and an electronic circuit that performs communication with the electronic control unit  32  in accordance with the output signal of the sensor. The operation unit  14  includes one or more operation members that change riding modes of the motor  22 . The operation members include a push switch, a lever type switch and a touch panel. If a rider operates the operation unit  14 , then the operation unit  14  transmits a switch signal that switches riding modes of the bicycle  10  to the electronic control unit  32 . The riding modes include a first mode and a second mode. The first mode is suitable for rough roads that are bumpy. The second mode is suitable for even roads. 
     The battery  16  includes one or more battery cells. The battery cells include rechargeable batteries. The battery  16  is electrically connected to a motor  22  of the assist device  18  to supply the motor  22  with power. The battery  16  supplies power to the bicycle controller  30  and other electronic components that are mounted on the bicycle  10  and electrically connected to the battery  16  by wires. 
     The assist device  18  includes a drive circuit  20  and the motor  22 . The drive circuit  20  controls the power supplied from the battery  16  to the motor  22 . The motor  22  assists propulsion of the bicycle  10 . The motor  22  includes an electric motor. The motor  22  is configured to transmit rotation to a manual driving force transmission path, which extends from the pedals  12 D to a rear wheel (not shown) or a front wheel (not shown). The motor  22  is arranged on a frame (not shown), the rear wheel, or the front wheel of the bicycle  10 . In one example, the motor  22  is connected to a power transmission path that extends from the crankshaft  12 B to a front rotating body. It is preferred that the power transmission path from the motor  22  to the crankshaft  12 B include a one-way clutch (not shown) that is configured so that the crank rotation force produced by the rotation of the crankshaft  12 B to move the bicycle forward does not affect the rotation produced by the motor  22 . The assist device  18  can include a reduction gear that reduces the speed of the rotation produced by the motor  22  before outputting the rotation. 
     The bicycle controller  30  includes the electronic control unit  32 . In one example, the bicycle controller  30  further includes a memory  34 , an inclination detector  36 , a torque sensor  38 , and a rotational angle sensor  40 . 
     The electronic control unit  32  includes one or more processors that executes predetermined control programs. The processor(s) includes, for example, a central processing unit (CPU) or a micro-processing unit (MPU). The memory  34  stores information used for various control programs and various control processes. The memory  34  includes, for example, a non-volatile memory and a volatile memory. The memory  34  is one or more storage devices (i.e., one or more computer memory devices). The memory  34  can be, for example, any a non-transitory computer readable medium such as a ROM (Read Only Memory) device, a RAM (Random Access Memory) device, a hard disk, a flash drive, etc. The memory  34  is configured to store settings, programs, data, calculations and/or results of the processor(s) of the electronic control unit  32 . 
     The inclination detector  36  detects an inclination angle D of the bicycle  10 . The inclination detector  36  is configured to communicate with the electronic control unit  32  through a wired connection or a wireless connection. The inclination detector  36  includes a three-axis gyro sensor  36 A and a three-axis acceleration sensor  36 B. The output of the inclination detector  36  includes information related to the attitude angle on each of the three axes and the acceleration on each of the three axes. The three attitude angles include a pitch angle DA, a roll angle DB and a yaw angle DC. Preferably, the three axes of the gyro sensor  36 A coincide with the three axes of the acceleration sensor  36 B. The inclination detector  36  corrects the output of the gyro sensor  36 A in accordance with the output of the acceleration sensor  36 B and sends a signal to the electronic control unit  32  corresponding to the inclination angle D of the bicycle  10 . The inclination angle D of the bicycle  10  is the absolute value of the pitch angle DA. In a case in which the bicycle  10  is traveling on an uphill, the pitch angle DA is positive. In a case in which the bicycle  10  is traveling on an uphill, an increase in the inclination angle D corresponds to an increase in the pitch angle DA. In a case in which the bicycle  10  is traveling on a downhill, the pitch angle DA is negative. In a case in which the bicycle  10  is on a downhill, an increase in the inclination angle D corresponds to a decrease in the pitch angle DA. The assist device  18  can include a one-axis acceleration sensor or a two-axis acceleration sensor instead of the gyro sensor  36 A and the acceleration sensor  36 B. 
     The torque sensor  38  outputs a signal that is in accordance with a manual driving force T. The torque sensor  38  detects the manual driving force T applied to the crankshaft  12 B. The torque sensor  38  can be arranged between the crankshaft  12 B and the front rotating body (not shown). Alternatively, the torque sensor  38  can be arranged on the crankshaft  12 B or the front sprocket. As another option, the torque sensor  38  can be arranged on the crank arms  12 C or the pedals  12 D. The torque sensor  38  can be realized by, for example, a strain sensor, a magnetostrictive sensor, an optical sensor, a pressure sensor, or the like. Any sensor can be used as the torque sensor  38  as long as the sensor outputs a signal corresponding to the manual driving force T applied to the crank arms  12 C or the pedals  12 D. 
     The rotational angle sensor  40  detects a crank rotation speed N and a rotational angle of the crank  12 A. The rotational angle sensor  40  is attached to the frame (not shown) of the bicycle  10  or a housing (not shown) of the assist device  18 . The rotational angle sensor  40  includes a first element  40 A and a second element  40 B. The first element  40 A detects the magnetic field of a first magnet M 1 . The second element  40 B outputs a signal corresponding to the positional relationship with a second magnet M 2 . The first magnet M 1  is arranged on the crankshaft  12 B or the crank arms  12 C and coaxial with the crankshaft  12 B. The first magnet M 1  is an annular magnet, in which multiple magnetic poles are alternately arranged in the circumferential direction. The first element  40 A detects the rotational angle of the crank  12 A relative to the frame. The first element  40 A outputs a signal as the crank  12 A completes a single rotation. A single cycle of the signal corresponds to the angle obtained by dividing 360 degrees by the number of magnetic poles having the same polarity. The minimum value of the rotational angle of the crank  12 A that is detectable by the rotational angle sensor  40  is 180 degrees or smaller, preferably, 15 degrees, and further preferably, 6 degrees. The second magnet M 2  is arranged on the crankshaft  12 B or the crank arms  12 C. The second element  40 B detects a reference angle of the crank  12 A relative to the frame (e.g., top dead center or bottom dead center of crank  12 A). The second element  40 B outputs a signal of which a single cycle is one rotation of the crankshaft  12 B. 
     Instead of the first element  40 A and the second element  40 B, the rotational angle sensor  40  can include a magnetic sensor that outputs a signal in accordance with the intensity of the magnetic field. In this case, instead of the first magnet M 1  and the second magnet M 2 , an annular magnet of which the magnetic field intensity varies in the circumferential direction is arranged on the crankshaft  12 B coaxially with the crankshaft  12 B. The use of the magnetic sensor that outputs a signal corresponding to the magnetic field intensity allows the crank rotation speed N and the rotational angle of the crank  12 A to be detected with a single sensor. This simplifies the structure and facilitates the assembling. 
     The electronic control unit  32  is configured (programmed) control the motor  22  in accordance with the manual driving force T. The electronic control unit  32  uses a low-pass filter  52  to change the response speed of the motor  22  with respect to changes in the manual driving force T. The electronic control unit  32  is configured to change the response speed of the motor  22  if the manual driving force T decreases. The response speed of the motor  22  in a case in which the manual driving force T decreases is referred to as the response speed R. 
     The electronic control unit  32  is configured to change the response speed R in accordance with the inclination angle D of the bicycle  10 . The electronic control unit  32  is configured to change the response speed R in a stepped manner in accordance with the inclination angle D of the bicycle  10 . Further, the electronic control unit  32  is configured to change the response speed R in accordance with the crank rotation speed N. The electronic control unit  32  is configured to switch between the first mode and the second mode in accordance with the operation of the operation unit  14 . The first mode and the second mode differ from each other in the response speed R with respect to the inclination angle D and the crank rotation speed N. 
     As the inclination angle D of the bicycle  10  increases on an uphill, the electronic control unit  32  is configured to decrease the response speed R of the motor  22 . As the inclination angle D of the bicycle  10  on an uphill becomes greater than or equal to a first angle D 1 , the electronic control unit  32  is configured to fix the response speed R. More specifically, in the first mode, the electronic control unit  32  is configured to decrease the response speed of the motor  22  as the inclination angle D of the bicycle  10  increases on an uphill. Further, in the first mode, the electronic control unit  32  is configured to fix the response speed R as the inclination angle D of the bicycle  10  on an uphill becomes greater than or equal to the first angle D 1 . In the second mode, the electronic control unit  32  is also configured to decrease the response speed of the motor  22  as the inclination angle D of the bicycle  10  increases on an uphill. 
     As the inclination angle D of the bicycle  10  increases on a downhill, the electronic control unit  32  is configured to increase the response speed R. As the inclination angle D of the bicycle  10  on a downhill becomes greater than or equal to a second angle D 2 , the electronic control unit  32  is configured to fix the response speed R. More specifically, in the second mode, the electronic control unit  32  is configured to increase the response speed R as the inclination angle D of the bicycle  10  increases on a downhill. Further, in the second mode, the electronic control unit  32  is configured to fix the response speed R as the inclination angle D of the bicycle  10  on a downhill becomes greater than or equal to the second angle D 2 . In the first mode, the electronic control unit  32  can also increase the response speed R as the inclination angle D of the bicycle  10  increases on a downhill and fix the response speed R as the inclination angle D of the bicycle  10  on a downhill becomes greater than or equal to the second angle D 2 . 
     The electronic control unit  32  is configured to control the motor  22  in the first mode that decreases the response speed R as the crank rotation speed N increases. Further, in the first mode, the electronic control unit  32  fixes the response speed R as the crank rotation speed N becomes higher than or equal to a first speed N 1 . The electronic control unit  32  is also configured to control the motor  22  in the second mode that increases the response speed R as the crank rotation speed N increases. Further, in the second mode, the electronic control unit  32  is configured to fix the response speed R as the crank rotation speed N becomes higher than or equal to a second speed N 2 . 
     The electronic control unit  32  includes a mode switching unit  42 , a manual driving force computation unit  44 , an increase-decrease determination unit  46 , a correction unit  48  and an output computation unit  50 . The processor of the electronic control unit  32  executes programs to function as the mode switching unit  42 , the manual driving force computation unit  44 , the increase-decrease determination unit  46 , the correction unit  48  and the output computation unit  50 . 
     The mode switching unit  42  switches the riding mode of the bicycle  10  based on a switch signal from the operation unit  14 . In a case in which the mode switching unit  42  receives a switch signal from the operation unit  14  for switching the riding mode to the first mode, the mode switching unit  42  transmits a signal to the correction unit  48  for setting a first map that corresponds to the first mode and is stored in the memory  34 . In a case in which the mode switching unit  42  receives a switch signal from the operation unit  14  for switching the riding mode to the second mode, the mode switching unit  42  transmits a signal to the correction unit  48  for setting a second map that corresponds to the second mode and is stored in the memory  34 . 
     The manual driving force computation unit  44  is configured to compute the manual driving force T based on the output from the torque sensor  38 . The increase-decrease determination unit  46  determines whether the manual driving force T is increasing or decreasing. For example, the increase-decrease determination unit  46  determines whether the manual driving force T in the present computation cycle has increased or decreased from the manual driving force T of the previous computation cycle. 
     The correction unit  48  includes the low-pass filter  52  and a response speed setting unit  54 . The correction unit  48  is configured to correct the manual driving force T. The low-pass filter  52  is a linear low-pass filter. The low-pass filter  52  uses a time constant K to correct the manual driving force T to a corrected driving force TX. An increase in the time constant K decreases the response speed R and retards changing of the corrected driving force TX with respect to the manual driving force T. 
     The response speed setting unit  54  sets the time constant K used by the low-pass filter  52 . The response speed setting unit  54  sets the time constant K based on the first or second map, which is set by the mode switching unit  42 , the inclination angle D, and the crank rotation speed N. 
     The output computation unit  50  is configured to compute the output of the motor  22  (hereinafter referred to as “the motor output TM”) based on the manual driving force T. The output computation unit  50  computes the motor output TM as, for example, at least one of the motor torque and the motor rotation speed. The output computation unit  50  selects one of the manual driving force T and the corrected driving force TX based on the determination result of the increase-decrease determination unit  46  and the comparison result of the manual driving force T and the corrected driving force TX. Then, the output computation unit  50  computes the motor output TM based on the selected one of the manual driving force T and the corrected driving force TX. More specifically, in a case in which the manual driving force T decreases, the output computation unit  50  computes the motor output TM by multiplying the corrected driving force TX by a predetermined value. In a case in which the manual driving force T increases and the manual driving force T is less than the corrected driving force TX, the output computation unit  50  computes the motor output TM by multiplying the corrected driving force TX by a predetermined value. In a case in which the manual driving force T increases and the manual driving force T is greater than or equal the corrected driving force TX, the output computation unit  50  computes the motor output TM by multiplying the manual driving force T by a predetermined value. The predetermined value is changed in accordance with the riding mode. The ratio of the motor output TM to the manual driving force T differs between riding mode. The rider switches the riding mode by operating the operation unit  14 . The electronic control unit  32  sends a control signal to the drive circuit  20  based on the computed motor output TM. 
     The motor control executed by the electronic control unit  32  will now be described with reference to  FIG. 2 . While the electronic control unit  32  is being supplied with power, the motor control is executed in predetermined cycles. In step S 11 , the electronic control unit  32  computes the manual driving force T. In step S 12 , the electronic control unit  32  determines whether or not the present riding mode is the first mode. If the electronic control unit  32  determines that the riding mode is the first mode, then the electronic control unit  32  proceeds to step S 13 . In step S 13 , the electronic control unit  32  computes the corrected driving force TX based on the first map, the inclination angle D, the crank rotation speed N and the manual driving force T. Then, the electronic control unit  32  proceeds to step S 14 . 
     In step S 14 , the electronic control unit  32  determines whether or not the manual driving force T is decreasing. For example, if the manual driving force T in the present computation cycle is less than the manual driving force T in the preceding computation cycle, then the electronic control unit  32  determines that the manual driving force T is decreasing. 
     If the electronic control unit  32  determines in step S 14  that the manual driving force T is decreasing, then the electronic control unit  32  proceeds to step S 15  and computes the motor output TM based on the corrected driving force TX, which was computed in step S 13 . Then, the electronic control unit  32  proceeds to step S 16 . In step S 16 , the electronic control unit  32  controls the motor  22  based on the motor output TM. Then, after a predetermined cycle, the electronic control unit  32  starts the process again from step S 11 . 
     In a case in which the first mode is selected and the crank rotation speed N does not change, the response speed R is decreased as the inclination angle D increases on an uphill. In a case in which the first mode is selected and the inclination angle D on an uphill is greater than or equal to the first angle D 1 , the response speed R is set to a first value R1. In a case in which the first mode is selected and the inclination angle D does not change, the response speed R is decreased if the crank rotation speed N is increased. In a case in which the first mode is selected and the crank rotation speed N is higher than or equal to the first speed N 1 , the response speed R is fixed. 
     Referring to  FIG. 3 , in the first map, the time constant K for a given crank rotation speed N increases as the pitch angle DA increases. Thus, in the first map, as the inclination angle D increases on an uphill, the time constant K for a given crank rotation speed N increases, and the response speed R decreases. 
     In  FIG. 3 , a first line L 11  indicates the relationship of the crank rotation speed N and the time constant K in a case in which the pitch angle DA is a first pitch angle DA 1 . The first line L 11  is the solid line. A second line L 12  indicates the relationship of the crank rotation speed N and the time constant K in a case in which the pitch angle DA is a second pitch angle DA 2 . The second line L 12  is the dotted line. A third line L 13  indicates the relationship of the crank rotation speed N and the time constant K in a case in which the pitch angle DA is a third pitch angle DA 3 . The third line L 13  is the single-dashed line. The first pitch angle DA 1 , the second pitch angle DA 2 , and the third pitch angle DA 3  have a relationship of DA 1 &gt;DA 2 &gt;DA 3 . The first pitch angle DA 1 , which is a positive value, is the pitch angle DA of the bicycle  10  that corresponds to a road gradient of 10%. In a case in which the pitch angle DA is the first pitch angle DA 1 , the inclination angle D of the bicycle  10  on an uphill is the first angle D 1 . In one example, the first pitch angle DA 1  is +5.7 degrees, the second pitch angle DA 2  is +2.8 degrees, and the third pitch angle DA 3  is 0 degrees. 
     In the first map, the time constant K is constant if the pitch angle DA is greater than or equal to the first pitch angle DA 1 . As shown by the first line L 11 , if the pitch angle DA is the first pitch angle DA 1 , then a first predetermined value K1 is selected as the time constant K regardless of the crank rotation speed N. 
     In the first map, the time constant K increases as the crank rotation speed N increases if the pitch angle DA is less than the first pitch angle DA 1 . Further, in the first map, the time constant K is constant if the crank rotation speed N becomes higher than or equal to the first speed N 1  if the pitch angle DA is less than the first pitch angle DA 1 . In one example, in a case in which the crank rotation speed N becomes higher than or equal to the first speed N 1  if the pitch angle DA is less than the first pitch angle DA 1 , the time constant K is equal to the time constant K1, which is for a case in which the pitch angle DA is greater than or equal to the first pitch angle DA 1 . 
     As shown by the second line L 12 , if the pitch angle DA is the second pitch angle DA 2 , then the time constant K increases in a linear manner as the crank rotation speed N increases, and the time constant K is set to the first predetermined value K1 as the crank rotation speed N becomes higher than or equal to the first speed N 1 . As shown by the third line L 13 , if the pitch angle DA is the third pitch angle DA 3 , then the time constant K increases in a linear manner as the crank rotation speed N increases, and the time constant is set to the first predetermined value K1 as the crank rotation speed N becomes higher than or equal to the first speed N 1 . If the pitch angle DA is the third pitch angle DA 3  and the crank rotation speed N is lower than the first speed N 1 , under a condition in which the crank rotation speed N is the same, then the time constant K is less than that for a case in which the pitch angle DA is the second pitch angle DA 2 . 
     In the first map, the relationship of the crank rotation speed N and the time constant K in a case in which the crank rotation speed N is lower than or equal to the first speed N 1  is set in advance with a first computation equation. The first computation equation includes a coefficient that is determined in accordance with the inclination angle D. The first computation equation is, for example, as shown below by equation (1).
 
 K =(4× A 1× N )+( L 1× A 2)  (1)
 
     In equation (1), “L 1 ” represents a constant, “N” represents the crank rotation speed N, “A1” represents a coefficient determined in accordance with the inclination angle D, and “A2” represents a coefficient determined in accordance with the inclination angle D. Further, “A1” is set to decrease as the inclination angle D increases, and “A2” is set to increase as the inclination angle D increases. Table 1 shows one example of the relationship of “A1” and “A2” with respect to the inclination angle D. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Pitch 
                   
                 Inclination 
                   
                   
                   
               
               
                   
                 Angle 
                 Road 
                 Angle 
                 Gradient 
                 A1 
                 A2 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 1st Pitch 
                 +5.7° 
                 Uphill 
                 5.7° 
                 +10% 
                 0 
                 2 
               
               
                 Angle DA1 
                   
                   
                   
                   
                   
                   
               
               
                 2nd Pitch 
                 +2.8° 
                 Uphill 
                 2.8° 
                 +5% 
                 0.5 
                 1.0 
               
               
                 angle DA2 
                   
                   
                   
                   
                   
                   
               
               
                 3rd Pitch 
                     0° 
                   
                   0° 
                   0% 
                 1.0 
                 0 
               
               
                 Angle DA3 
                   
                   
                   
                   
                   
                   
               
               
                   
               
            
           
         
       
     
     As shown in  FIG. 2 , if the electronic control unit  32  determines in step S 12  that the present riding mode is not the first mode, that is, the present mode is the second mode, then the electronic control unit  32  proceeds to step S 17 . In step S 17 , the electronic control unit  32  computes the corrected driving force TX based on the second map, the inclination angle D, the crank rotation speed N and the manual driving force T. Then, the electronic control unit  32  proceeds to step S 14 . 
     In step S 14 , the electronic control unit  32  determines whether or not the manual driving force T is decreasing. If the electronic control unit  32  determines in step S 14  that the manual driving force T is decreasing, in step S 15 , then the electronic control unit  32  computes the motor output TM based on the corrected driving force TX, which has been computed in step S 17 , and proceeds to step S 16 . In step S 16 , the electronic control unit  32  controls the motor  22  based on the motor output TM. Then, after a predetermined cycle, the electronic control unit  32  starts the process again from step S 11 . 
     In a case in which the second mode is selected and the crank rotation speed N does not change, the response speed R increases as the inclination angle D increases on a downhill. In a case in which the second mode is selected and the inclination angle D is less than or equal to the second angle D 2  on a downhill, the response speed R is a second value R2. The response speed R is the highest if it is the second value R2. In one example, the second value R2 is equal to the response speed R if the manual driving force T is increasing. In a case in which the second mode is selected and the inclination angle D does not change, the response speed R is increased as the crank rotation speed N increases. In a case in which the second mode is selected and the crank rotation speed N becomes higher than or equal to the second speed N 2 , the response speed R is fixed. 
     As shown in  FIG. 4 , in the second map, the time constant K for a given crank rotation speed N increases as the pitch angle DA increases. Thus, in the second map, as the inclination angle D increases on a downhill, the time constant K for a given crank rotation speed N decreases. This decreases the response speed R. 
     In  FIG. 4 , a first line L 21  indicates the relationship of the crank rotation speed N and the time constant K in a case in which the pitch angle DA is a fourth pitch angle DA 4 . The first line L 21  is the solid line. A second line L 22  indicates the relationship of the crank rotation speed N and the time constant K in a case in which the pitch angle DA is a fifth pitch angle DA 5 . The second line L 22  is the single-dashed line. A third line L 23  indicates the relationship of the crank rotation speed N and the time constant K in a case in which the pitch angle DA is a sixth pitch angle DA 6 . The third line L 23  is the dashed line. A fourth line L 24  indicates the relationship of the crank rotation speed N and the time constant K in a case in which the pitch angle DA is a seventh pitch angle DA 7 . The fourth line L 24  is the dotted line. A fifth line L 25  indicates the relationship of the crank rotation speed N and the time constant K in a case in which the pitch angle DA is an eighth pitch angle DA 8 . The fifth line L 25  is the double-dashed line. The fourth pitch angle DA 4 , the fifth pitch angle DA 5 , the sixth pitch angle DA 6 , the seventh pitch angle DA 7 , and the eighth pitch angle DA 8  have a relationship of DA 4 &lt;DA 5 &lt;DA 6 &lt;DA 7 &lt;DA 8 . The fourth pitch angle DA 4 , which is a negative value, is the pitch angle DA of the bicycle  10  corresponding to a road gradient of, for example, minus 10%. If the pitch angle DA is the fourth pitch angle DA 4 , then the inclination angle D of the bicycle  10  on a downhill is the second angle D 2 . In one example, the fourth pitch angle DA 4  is −5.7 degrees, the fifth pitch angle DA 5  is −2.8 degrees, the sixth pitch angle DA 6  is zero degrees, the seventh pitch angle DA 7  is +2.8 degrees, and the eighth pitch angle DA 8  is +5.7 degrees. 
     In the second map, the time constant K is constant if the pitch angle DA is less than or equal to the fourth pitch angle DA 4 . As shown by the first line L 21 , in a case in which the pitch angle DA is the fourth pitch angle DA 4 , a second predetermined value K2 is selected as the time constant K regardless of the crank rotation speed N. The second predetermined value K2 is, for example, 0. 
     In the second map, the time constant K decreases as the crank rotation speed N increases if the pitch angle DA is greater than the fourth pitch angle DA 4 . Further, in the second map, the time constant K is constant if the crank rotation speed N becomes higher than or equal to the second speed N 2  if the pitch angle DA is greater than the fourth pitch angle DA 4 . In one example, in a case in which the crank rotation speed N becomes higher than or equal to the second speed N 2  if the pitch angle DA is greater than the fourth pitch angle DA 4 , the time constant K is equal to the time constant K2 for a case in which the pitch angle DA is less than or equal to the fourth pitch angle DA 4 . 
     As shown by the second line L 22 , if the pitch angle DA is the fifth pitch angle DA 5 , then the time constant K decreases in an exponential manner as the crank rotation speed N increases, and the time constant K is set to the second predetermined value K2 if the crank rotation speed N becomes higher than or equal to the second speed N 2 . 
     As shown by the third line L 23 , if the pitch angle DA is the sixth pitch angle DA 6 , then the time constant K decreases in an exponential manner as the crank rotation speed N increases, and the time constant K is set to the second predetermined value K2 if the crank rotation speed N becomes higher than or equal to the second speed N 2 . If the pitch angle DA is the sixth pitch angle DA 6  and the crank rotation speed N is lower than the second speed N 2 , under a condition in which the crank rotation speed N is the same, then the time constant K is greater than that for a case in which the pitch angle DA is the fifth pitch angle DA 5 . 
     As shown by the fourth line L 24 , if the pitch angle DA is the seventh pitch angle DA 7 , then the time constant K decreases in an exponential manner as the crank rotation speed N increases, and the time constant K is set to the second predetermined value K2 if the crank rotation speed N becomes higher than or equal to the second speed N 2 . If the pitch angle DA is the seventh pitch angle DA 7  and the crank rotation speed N is lower than the second speed N 2 , under a condition in which the crank rotation speed N is the same, then the time constant K is greater than that for a case in which the pitch angle DA is the sixth pitch angle DA 6 . 
     As shown by the fifth line L 25 , if the pitch angle DA is the eighth pitch angle DA 8 , then the time constant K decreases in an exponential manner as the crank rotation speed N increases, and the time constant K is set to the second predetermined value K2 if the crank rotation speed N becomes higher than or equal to the second speed N 2 . If the pitch angle DA is the eighth pitch angle DA 8  and the crank rotation speed N is lower than the second speed N 2 , under a condition in which the crank rotation speed N is the same, then the time constant K is greater than that for a case in which the pitch angle DA is the seventh pitch angle DA 7 . 
     In the second map, the relationship of the crank rotation speed N and the time constant K if the crank rotation speed N is lower than or equal to the second speed N 2  is set in advance with a second computation equation. The second computation equation includes a coefficient that is determined in accordance with the pitch angle DA. The second computation equation is, for example, as shown below by equation (2).
 
 K =( L 2× B )÷100÷ N× 1000  (2)
 
     In equation (2), “L 2 ” represents a constant, “N” represents the crank rotation speed N, and “B” represents a coefficient determined in accordance with the pitch angle DA. Further, “B” is set to increase as the pitch angle DA increases. Table 2 shows one example of the relationship of “B” and the pitch angle DA. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                 Pitch  
                   
                 Inclination  
                   
                   
               
               
                   
                 Angle  
                 Road  
                 Angle  
                 Gradient  
                 B 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 4th Pitch  
                 −5.7° 
                 Downhill  
                 5.7° 
                 −10%  
                 0  
               
               
                 Angle DA4  
                   
                   
                   
                   
                   
               
               
                 5th Pitch  
                 −2.8° 
                 Downhill  
                 2.8° 
                  −5%  
                 0.5  
               
               
                 Angle DA5  
                   
                   
                   
                   
                   
               
               
                 6th Pitch  
                 0°  
                   
                 0°   
                  0%  
                 1.0  
               
               
                 Angle DA6  
                   
                   
                   
                   
                   
               
               
                 7th Pitch  
                 +2.8°  
                 Uphill  
                 2.8°  
                  +5%  
                 1.5  
               
               
                 Angle DA7  
                   
                   
                   
                   
                   
               
               
                 8th Pitch  
                 +5.7°  
                 Uphill  
                 5.7°  
                 +10%  
                 2.0  
               
               
                 Angle DA8 
               
               
                   
               
            
           
         
       
     
     As shown in  FIG. 2 , if the electronic control unit  32  determines in step S 14  that the manual driving force T is not decreasing, then the electronic control unit  32  proceeds to step S 18  and determines whether or not the manual driving force T is greater than the corrected driving force TX. If the electronic control unit  32  determines in step S 18  that the manual driving force T is greater than the corrected driving force TX, then the electronic control unit  32  proceeds to step S 19  and computes the motor output TM based on the manual driving force T. Then, the electronic control unit  32  proceeds to step S 16 . In step S 16 , the electronic control unit  32  controls the motor  22  based on the motor output TM. Then, after a predetermined cycle, the electronic control unit  32  starts the process again from step S 11 . 
     If the electronic control unit  32  determines in step S 18  that the manual driving force T is less than or equal to the corrected driving force TX, then the electronic control unit  32  proceeds to step S 15  and computes the motor output TM based on the corrected driving force TX. Then, the electronic control unit  32  proceeds to step S 16 . In step S 16 , the electronic control unit  32  controls the motor  22  based on the motor output TM. Then, after a predetermined cycle, the electronic control unit  32  starts the process again from step S 11 . In this manner, during the period in which the manual driving force T is increasing, the electronic control unit  32  controls the motor  22  based on the greater one of the manual driving force T and the corrected driving force TX. 
     With reference to  FIG. 5 , one example of the motor control that is executed in a case in which the first mode is selected will now be described. Timing chart A of  FIG. 5  shows the relationship of time and the manual driving force T. Timing chart B of  FIG. 5  shows the relationship of time and the pitch angle DA. Timing chart C of  FIG. 5  shows the relationship of time and the motor output TM. Further, the timing charts A to C of  FIG. 5  show a state in which the crank rotation speed N is constant as the bicycle  10  travels. In the timing chart C of  FIG. 5 , the solid line represents the motor output TM in a case in which the inclination angle D changes as the bicycle  10  travels, and the double-dashed line represents the motor output TM in a case in which the inclination angle D does not change as the bicycle  10  travels. 
     In the timing charts A to C of  FIG. 5 , in the period from time t 10  to time t 11 , the pitch angle DA is greater than or equal to the first pitch angle DA 1 . During this period, in a case in which the manual driving force T is greater than the corrected driving force TX, if the manual driving force T is increased, that is, if the crank arms  12 C (refer to  FIG. 1 ) are rotated from the top dead center or the bottom dead center toward an intermediate angle between the top dead center and the bottom dead center, then the motor output TM is changed at an increase rate that is substantially equal to the increase rate of the manual driving force T. If the manual driving force T is decreased, that is, if the crank arms  12 C (refer to  FIG. 1 ) are rotated from an intermediate angle between the top dead center and the bottom dead center toward the top dead center or the bottom dead center, then the motor output TM is decreased at a decrease rate that is more gradual than the decrease rate of the manual driving force T. 
     At time t 11 , the pitch angle DA becomes less than or equal to the first pitch angle DA 1  but is greater than the second pitch angle DA 2 . Here, the electronic control unit  32  decreases the time constant K in accordance with the pitch angle DA. Thus, the decrease rate of the corrected driving force TX becomes greater than the decrease rate of the period from time t 10  to t 11 , and the decrease rate of the corrected driving force TX approaches the decrease rate of the manual driving force T. Further, the decrease rate of the motor output TM approaches the decrease rate of the manual driving force T. That is, the response speed R of the motor  22  is increased with respect to a change in the manual driving force T. In a case in which the pitch angle DA remains less than or equal to the first pitch angle DA 1  but greater than the second pitch angle DA 2 , if the manual driving force T decreases, then the electronic control unit  32  controls the motor  22  with a fixed response speed R. 
     At time t 12 , the pitch angle DA becomes less than or equal to the second pitch angle DA 2  but is greater than the third pitch angle DA 3 . Thus, the decrease rate of the corrected driving force TX becomes greater than the decrease rate of the period from time t 11  to time t 12 . Further, the decrease rate of the motor output TM further approaches the decrease rate of the manual driving force T. That is, the response speed R of the motor  22  is increased with respect to the manual driving force T. In a case in which the pitch angle DA remains greater than or equal to the third pitch angle DA 3 , if the manual driving force T is decreased, then the electronic control unit  32  controls the motor  22  with a fixed response speed R. 
     With reference to  FIG. 6 , one example of the motor control in a case in which the second mode is selected will now be described. Timing chart A of  FIG. 6  shows the relationship of time and the manual driving force T. Timing chart B of  FIG. 6  shows the relationship of time and the pitch angle DA. Timing chart C of  FIG. 6  shows the relationship of time and the motor output TM. Further, the timing charts A to C of  FIG. 6  show a state in which the crank rotation speed N is constant as the bicycle  10  travels. In the timing chart C of  FIG. 6 , the solid line represents the motor output TM in a case in which the inclination angle D changes as the bicycle  10  travels, and the double-dashed line represents the motor output TM in a case in which the inclination angle D does not change as the bicycle  10  travels. 
     In the timing charts A to C of  FIG. 6 , in the period from time t 20  to t 21 , the pitch angle DA is less than or equal to the sixth pitch angle DA 6  but greater than the fifth pitch angle DA 5 . During this period, in a case in which the manual driving force T is greater than the corrected driving force TX, if the manual driving force T is increased, then the motor output TM is changed at an increase rate that is substantially equal to the increase rate of the manual driving force T. If the manual driving force T is decreased, then the motor output TM is decreased at a decrease rate that is more gradual than the decrease rate of the manual driving force T. 
     At time t 21 , the pitch angle DA becomes less than or equal to the fifth pitch angle DA 5  but is greater than the fourth pitch angle DA 4 . Here, the electronic control unit  32  decreases the time constant K in accordance with the pitch angle DA. Thus, the decrease rate of the corrected driving force TX is increased, and the decrease rate of the corrected driving force TX approaches the decrease rate of the manual driving force T. Further, the decrease rate of the motor output TM approaches the decrease rate of the manual driving force T. That is, the response speed R of the motor  22  is increased with respect to a change in the manual driving force T. In a case in which the pitch angle DA remains less than or equal to the fifth pitch angle DA 5  and greater than the fourth pitch angle DA 4 , if the manual driving force T decreases, then the electronic control unit  32  controls the motor  22  with a fixed response speed R. 
     At time t 22 , the pitch angle DA becomes less than or equal to the fourth pitch angle DA 4 . Here, the electronic control unit  32  sets the time constant K to “0.” Thus, the decrease rate of the corrected driving force TX is increased, and the decrease rate of the corrected driving force TX becomes substantially equal to the decrease rate of the manual driving force T. Further, the decrease rate of the motor output TM becomes substantially equal to the decrease rate of the manual driving force T. That is, the response speed R of the motor  22  is increased with respect to a change in the manual driving force T. In a case in which the pitch angle DA remains less than or equal to the fourth pitch angle DA 4 , the electronic control unit  32  controls the motor  22  with a fixed response speed R. 
     The advantages of the bicycle controller  30  will now be described. 
     The bicycle controller  30  keeps the motor output TM high in a case in which the inclination angle D is large on an uphill. This reduces the load on the rider in a case in which the rider rides the bicycle  10  on an uphill. The bicycle controller  30  changes the motor output TM with a high responsivity in accordance with changes in the manual driving force T on a downhill or an even road. This allows the rider to easily control the bicycle  10  while riding downhill or on an even road. 
     The force acting on the rear of the bicycle  10  in a case in which the bicycle  10  travels off-road on a bumpy uphill is greater than that in a case in which the bicycle  10  is traveling on an even uphill. In such a case, as long as the first mode is selected, the bicycle controller  30  will function so that the rider hardly notices any lack in the motor output TM. 
     Second Embodiment 
     With reference to  FIGS. 1 and 7 to 9 , a second embodiment of the bicycle controller  30  will now be described. The second embodiment of the bicycle controller  30  is similar to the first embodiment of the bicycle controller  30  except in that a response speed Q of the motor  22  changes in accordance with the inclination angle D even in a case in which the manual driving force T increases. Same reference numerals are given to those components that are the same as the corresponding components of the first embodiment. Such components will not be described in detail. 
     In a case in which the manual driving force T increases, the electronic control unit  32  changes the response speed of the motor  22 . The response speed of the motor  22  in a case in which the manual driving force T increases is referred to as the response speed Q. The electronic control unit  32  can change the response speed Q in a stepped manner in accordance with the inclination angle D of the bicycle  10 . Alternatively, the electronic control unit  32  can change the response speed Q in a continuous manner in accordance with the inclination angle D of the bicycle  10 . 
     In a case in which the inclination angle D of the bicycle  10  increases on an uphill, the electronic control unit  32  increases the response speed Q. In a case in which the inclination angle D of the bicycle  10  increases on an uphill, the electronic control unit  32  increases the response speed Q of the motor  22  as the manual driving force T increases. In a case in which the inclination angle D of the bicycle  10  becomes greater than or equal to a first angle D 1  on an uphill, the electronic control unit  32  fixes the response speed Q if the manual driving force T increases. 
     In a case in which the inclination angle D of the bicycle  10  increases on a downhill, the electronic control unit  32  decreases the response speed Q. In a case in which the inclination angle D of the bicycle  10  increases on a downhill, the electronic control unit  32  decreases the response speed Q as the manual driving force T increases. In a case in which the inclination angle D of the bicycle  10  becomes greater than or equal to a second angle D 2  on a downhill, the electronic control unit  32  fixes the response speed Q if the manual driving force T increases. 
     The memory  34  stores a third map and a fourth map that set the relationship of the increasing speed of the manual driving force T, the inclination angle D, and a corrected value CX. In a case in which the manual driving force T increases, the electronic control unit  32  adds the corrected value CX to the manual driving force T or multiplies the manual driving force T by the corrected value CX to calculate a corrected driving force TX. 
     The third map sets the corrected value CX for cases in which the manual driving force T increases in the first mode. In one example, in the third map, the corrected value CX is set to increase as the increasing speed of the manual driving force T increases. Further, the corrected value CX is set to increase as the pitch angle DA increases. The fourth map sets the corrected value CX for cases in which the manual driving force T increases in the second mode. In one example, in the fourth map, the corrected value CX is set to increase as the increasing speed of the manual driving force T increases. Further, the corrected value CX is set to decrease as the pitch angle DA increases. In the third map, regardless of the increasing speed of the manual driving force T, the corrected value CX can be set to increase as the pitch angle DA increases. In the fourth map, regardless of the increasing speed of the manual driving force T, the corrected value CX can be set to decrease as the pitch angle DA decreases. 
     In a case in which the electronic control unit  32  adds the corrected value CX to the manual driving force T to calculate the corrected driving force TX, in the third and fourth maps, if the increasing speed of the manual driving force T is less than a predetermined speed, then the corrected value CX can be a negative value. In a case in which the electronic control unit  32  multiples the manual driving force T by the corrected value CX to calculate the corrected driving force TX, in the third and fourth maps, if the increasing speed of the manual driving force T is less than a predetermined speed, then the corrected value CX can be less than 1. 
     With reference to  FIG. 7 , the motor control executed by the electronic control unit  32  will now be described. In a state in which the electronic control unit  32  is being supplied with power, the motor control is executed in predetermined cycles. In step S 31 , the electronic control unit  32  calculates the manual driving force T. In step S 32 , the electronic control unit  32  determines whether or not the present riding mode is the first mode. The electronic control unit  32  proceeds to step S 33  if the electronic control unit  32  determines that the riding mode is the first mode. 
     In step S 33 , the electronic control unit  32  determines whether or not the manual driving force T is decreasing. If the electronic control unit  32  determines that the manual driving force T is decreasing, then the electronic control unit  32  proceeds to step S 34 . In step S 34 , the electronic control unit  32  calculates the corrected driving force TX based on the first map, the inclination angle D, the crank rotation speed N, and the manual driving force T and then proceeds to step S 35 . In step S 35 , the electronic control unit  32  calculates the motor output TM based on the calculated corrected driving force TX and proceeds to step S 36 . In step S 36 , the electronic control unit  32  controls the motor  22  based on the motor output TM and then executes the processing from step S 31  again after a predetermined cycle. 
     If the electronic control unit  32  determines in step S 33  that the manual driving force T is increasing or not changing, then the electronic control unit  32  proceeds to step S 37 . In step S 37 , the electronic control unit  32  calculates the corrected driving force TX based on the third map, the inclination angle D, and the manual driving force T and then proceeds to step S 35 . More specifically, the electronic control unit  32  calculates the corrected driving force TX by adding the corrected value CX, which is set in the third map, to the increasing speed of the manual driving force T or multiplying the increasing speed of the manual driving force T by the corrected value CX, which is set in the third map. In step S 35 , the electronic control unit  32  calculates the motor output TM based on the calculated corrected driving force TX and then proceeds to step S 36 . In step S 36 , the electronic control unit  32  controls the motor  22  based on the motor output TM and then executes the processing from step S 31  again after a predetermined cycle. 
     If the electronic control unit  32  determines in step S 32  that the present riding mode is not the first mode, that is, the present riding mode is the second mode, then the electronic control unit  32  proceeds to step S 38 . In step S 38 , the electronic control unit  32  determines whether or not the manual driving force T is decreasing. If the electronic control unit  32  determines that the manual driving force T is decreasing, then the electronic control unit  32  proceeds to step S 39 . In step S 39 , the electronic control unit  32  calculates the corrected driving force TX based on the second map, the inclination angle D, the crank rotation speed N, and the manual driving force T and then proceeds to step S 35 . In step S 35 , the electronic control unit  32  calculates the motor output TM based on the calculated corrected driving force TX and proceeds to step S 36 . In step S 36 , the electronic control unit  32  controls the motor  22  based on the motor output TM and then executes the processing from step S 31  again after a predetermined cycle. 
     If the electronic control unit  32  determines in step S 38  that the manual driving force T is increasing, then the electronic control unit  32  proceeds to step S 40 . In step S 40 , the electronic control unit  32  calculates the corrected driving force TX based on the fourth map, the inclination angle D, and the manual driving force T and then proceeds to step S 35 . More specifically, the electronic control unit  32  calculates the corrected driving force TX by adding the corrected value CX, which is set in the fourth map, to the increasing speed of the manual driving force T or multiplying the increasing speed of the manual driving force T by the corrected value CX, which is set in the fourth map. In step S 35 , the electronic control unit  32  calculates the motor output TM based on the calculated corrected driving force TX and then proceeds to step S 36 . In step S 36 , the electronic control unit  32  controls the motor  22  based on the motor output TM and then executes the processing from step S 31  again after a predetermined cycle. 
     Referring to  FIG. 8 , one example of the motor control in a case in which the first mode is selected will now be described. Timing chart A of  FIG. 8  shows the relationship of time and the manual driving force T. Timing chart B of  FIG. 8  shows the relationship of time and the pitch angle DA. Timing chart C of  FIG. 8  shows the relationship of time and the motor output TM. The timing charts A to C of  FIG. 8  show a state in which the bicycle  10  is travelling with the crank rotation speed N kept constant. The solid line in the timing chart C of  FIG. 8  shows the motor output TM in a case in which the inclination angle D changes while travelling. The double-dashed line in the timing chart C of  FIG. 8  shows the motor output TM in a case in which the inclination angle D does not change while travelling. 
     In the period from time t 30  to t 31  in the timing charts A to C of  FIG. 8 , the pitch angle DA is greater than or equal to a first pitch angle DA 1 . In the period from time t 30  to time t 31 , during period X 1  in which the corrected driving force TX decreases, the manual driving force T and the motor output TM change in the same manner as from time t 11  to time t 12  in the timing charts A to C of  FIG. 5 . In the period from time t 30  to time t 31 , during period X 2  in which the corrected driving force TX increases, that is, the crank arms  12  (refer to  FIG. 1 ) are rotated from the top dead center or the bottom dead center to an intermediate angle between the top dead center and the bottom dead center, the motor output TM is changed at an increase rate that is greater than the increase rate of the manual driving force T. 
     Time t 31  is the time at which the pitch angle DA becomes less than or equal to the first pitch angle DA 1  and greater than the second pitch angle DA 2 . In the period from time t 31  to time t 32 , during period X 1  in which the corrected driving force TX decreases, the manual driving force T and the motor output TM change in a manner similar to time t 11  to time t 12  in the timing charts A and C of  FIG. 5 . In the period from time t 31  to time t 32 , during period X 2  in which the corrected driving force TX increases, the electronic control unit  32  decreases the response speed Q in accordance with the pitch angle DA. The increase rate of the corrected driving force TX is less than that of the period from time t 30  to time t 31 . 
     Time t 32  is the time at which the pitch angle DA becomes less than or equal to the second pitch angle DA 2  but greater than the third pitch angle DA 3 . From time t 32 , during period X 1  in which the corrected driving force TX decreases, the manual driving force T and the motor output TM change in a manner similar to from time t 12  in timing charts A and C of  FIG. 5 . From time t 32 , during period X 2  in which the corrected driving force TX increases, the electronic control unit  32  decreases the response speed Q in accordance with the pitch angle DA. Thus, the increase rate of the corrected driving force TX becomes less than that of the period from time t 31  to time t 32 . 
     Referring to  FIG. 9 , one example of the motor control in a case in which the second mode is selected will now be described. Timing chart A of  FIG. 9  shows the relationship of time and the manual driving force T. Timing chart B of  FIG. 9  shows the relationship of time and the pitch angle DA. Timing chart C of  FIG. 9  shows the relationship of time and the motor output TM. The timing charts A to C of  FIG. 9  show a state in which the bicycle  10  is travelling with the crank rotation speed N kept constant. The solid line in the timing chart C of  FIG. 9  shows one example of the execution of the motor control in a case in which the inclination angle D changes while travelling. The double-dashed line in the timing chart C of  FIG. 9  shows one example of the motor control in a case in which the inclination angle D does not change while travelling. 
     In the period from time t 40  to t 41  in the timing charts A to C of  FIG. 9 , the pitch angle DA becomes less than or equal to the sixth pitch angle DA 6  but greater than the fifth pitch angle DA 5 . In the period from time t 40  to time t 41 , during period X 1  in which the corrected driving force TX decreases, the manual driving force T and the motor output TM change in the same manner as from time t 21  to time t 22  in the timing charts A to C of  FIG. 6 . In the period from time t 40  to time t 41 , during period X 2  in which the corrected driving force TX increases, that is, the crank arms  12  (refer to  FIG. 1 ) are rotated from the top dead center or the bottom dead center to an intermediate angle between the top dead center and the bottom dead center, the motor output TM is changed at an increase rate that is greater than the increase rate of the manual driving force T. 
     Time t 41  is the time at which the pitch angle DA becomes less than or equal to the fifth pitch angle DA 5  but greater than the fourth pitch angle DA 4 . In the period from time t 41  to time t 42 , during period X 1  in which the corrected driving force TX decreases, the manual driving force T and the motor output TM change in a manner similar to time t 21  to time t 22  in the timing charts A and C of  FIG. 6 . In the period from time t 41  to time t 42 , during period X 2  in which the corrected driving force TX increases, the electronic control unit  32  decreases the response speed Q in accordance with the pitch angle DA. The increase rate of the corrected driving force TX during period X 2  is less than that of the corrected driving force TX period from time t 40  to time t 41 . 
     Time t 42  is the time at which the pitch angle DA becomes less than or equal to the fourth pitch angle DA 4 . From time t 42 , during period X 1  in which the corrected driving force TX decreases, the manual driving force T and the motor output TM change in a manner similar to from time t 22  in timing charts A to C of  FIG. 6 . From time t 42 , during period X 2  in which the corrected driving force TX increases, the electronic control unit  32  decreases the response speed Q in accordance with the pitch angle DA. Thus, the increase rate of the corrected driving force TX becomes less than that of the period from time t 41  to time t 42 . 
     Third Embodiment 
     A third embodiment of the bicycle controller  30  will now be described with reference to  FIGS. 1, 10, and 11 . The third embodiment of the bicycle controller  30  is similar to the first embodiment of the bicycle controller  30  except in that a control is executed to change the response speed Q in accordance with the vehicle speed V and the inclination angle D. Same reference numerals are given to those components that are the same as the corresponding components of the first embodiment. Such components will not be described in detail. 
     In the present embodiment, the electronic control unit  32  shown in  FIG. 1  sets the response speeds R and Q for cases in which the vehicle speed V of the bicycle  10  is less than or equal to a first speed V 1  to be different from the response speeds R and Q for cases in which the vehicle speed V of the bicycle  10  exceeds the first speed V 1 . Preferably, the first speed V 1  is set at the vehicle speed V that allows for determination that the bicycle  10  has started to travel. Preferably, the first speed V 1  is set in a range from 1 to 10 km/h. In one example, the first speed V 1  is set to 3 km/h. Preferably, the first speed V 1  is stored beforehand in the memory  34 . The memory  34  is configured so that the first speed V 1  can be changed. For example, operation of the operation unit  14  or use of an external device changes the first speed V 1  stored in the memory  34 . The electronic control unit  32  sets the response speed Q for a case in which the vehicle speed V of the bicycle  10  is less than or equal to the first speed V 1  to be higher than the response speed Q for a case in which the vehicle speed V of the bicycle  10  exceeds the first speed V 1 . Further, the electronic control unit  32  sets the response speed R for a case in which the vehicle speed V of the bicycle  10  is less than or equal to the first speed V 1  to be lower than the response speed R for a case in which the vehicle speed V of the bicycle  10  exceeds the first speed V 1 . 
     The electronic control unit  32  sets the response speeds R and Q for a case during a predetermined period PX 1  from the time at which the bicycle  10  starts to travel to be different from the response speeds R and Q for a case in which the predetermined period PX 1  has elapsed. Preferably, the predetermined period PX 1  is set in the range of one to ten seconds. In one example, the predetermined period PX 1  is set to three seconds. Preferably, the predetermined period PX 1  is stored beforehand in the memory  34 . The memory  34  is configured to allow the predetermined period PX 1  to be changed. For example, operation of the operation unit  14  or use of an external device changes the predetermined period PX 1  stored in the memory  34 . The electronic control unit  32  sets the response speed Q for a case during the predetermined period PX 1  from the time at which the bicycle  10  starts to travel to be higher than the response speed Q for a case in which the predetermined period PX 1  has elapsed. The electronic control unit  32  sets the response speed R for a case during the predetermined period PX 1  from the time at which the bicycle  10  starts to travel to be lower than the response speed R for a case in which the predetermined period PX 1  has elapsed. 
     If the inclination angle D on an uphill increases, then the electronic control unit  32  decreases the response speed R in a case in which the manual driving force T decreases and increases the response speed Q in a case in which the manual driving force T increases. More specifically, on an uphill in which the pitch angle DA is greater than a first predetermined angle DX 1 , the electronic control unit  32  increases the response speed Q if the manual driving force T increases. The first predetermined angle DX 1  is set to a positive value, in one example, nine degrees. 
     If the inclination angle D on a downhill increases, then the electronic control unit  32  increases the response speed R for a case in which the manual driving force T decreases and decreases the response speed Q for a case in which the manual driving force T increases. More specifically, on a downhill in which the pitch angle DA is less than a second predetermined angle D 2 , the electronic control unit  32  increases the response speed Q for a case in which the manual driving force T increases. The second predetermined angle D 2  is set to a negative value, in one example, minus nine degrees. 
     With reference to  FIGS. 10 to 12 , a motor control that changes the response speeds R and Q in accordance with the inclination angle D of the vehicle speed V will now be described. The motor control is repeated in predetermined cycles as long as the electronic control unit  32  is supplied with power. 
     In step S 41 , the electronic control unit  32  determines whether or not the vehicle speed V is less than or equal to the first speed V 1 . If the electronic control unit  32  determines that the vehicle speed V is less than or equal to the first speed V 1 , then the electronic control unit  32  proceeds to step S 42 . In step S 42 , the electronic control unit  32  determines whether or not the pitch angle DA is greater than the first predetermined angle DX 1 . If the electronic control unit  32  determines that the pitch angle DA is greater than the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 43 . In step S 43 , the electronic control unit  32  decreases the response speed R and increases the response speed Q. Then, the electronic control unit  32  proceeds to step S 44 . For example, the electronic control unit  32  decreases the response speed R to a value lower than an initial value RX of the response speed R that is stored beforehand in the memory  34 , and the electronic control unit  32  increases the response speed Q to a value higher than an initial value QX of the response speed Q that is stored beforehand in the memory  34 . Preferably, the initial values QX and RX of the response speeds Q and R are set to values that are suitable for traveling on an even road in a case in which the vehicle speed V is greater than the first speed V 1 . 
     In step S 44 , the electronic control unit  32  determines whether or not the predetermined period PX 1  has elapsed. For example, if the elapsed time from the time at which the vehicle speed V was determined in step S 41  as being less than or equal to the first speed V 1  becomes greater than or equal to the predetermined period PX 1 , then the electronic control unit  32  determines that the predetermined period PX 1  has elapsed. The electronic control unit  32  repeats the determination of step S 44  until the predetermined period PX 1  elapses. Preferably, the predetermined period PX 1  is set in a range of one to ten seconds. In one example, the predetermined period PX 1  is set to three seconds. If the predetermined period PX 1  elapses, then the electronic control unit  32  proceeds to step S 45 . In step S 45 , the electronic control unit  32  returns the response speed R and the response speed Q to their original values. The process of step S 45  sets the response speed R and the response speed Q to the response speed R and the response speed Q prior to the change in step S 43 . For example, the electronic control unit  32  returns the response speed R and the response speed Q to the initial values QX and RX stored in the memory  34 . 
     If the electronic control unit  32  determines in step S 42  that the pitch angle DA is not greater than the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 46 . In step S 46 , the electronic control unit  32  determines whether or not the pitch angle DA is less than the second predetermined angle D 2 . If the electronic control unit  32  determines that the pitch angle DA is greater than or equal to the second predetermined angle D 2 , then the electronic control unit  32  ends the processing. Thus, in a case in which the bicycle  10  is on a road in which the pitch angle DA is less than or equal to the first predetermined angle DX 1  and greater than or equal to the second predetermined angle D 2 , the electronic control unit  32  ends the processing without changing the response speeds R and Q. 
     If the electronic control unit  32  determines that the pitch angle DA is less than the second predetermined angle D 2  in step S 46 , then the electronic control unit  32  proceeds to step S 47 . In step S 47 , the electronic control unit  32  increases the response speed R and decreases the response speed Q. Then, the electronic control unit  32  proceeds to step S 44 . For example, the electronic control unit  32  increases the response speed R to a value higher than the initial value RX of the response speed R that is stored beforehand in the memory  34  and decreases the response speed Q to a value lower than the initial value QX of the response speed Q that is stored beforehand in the memory  34 . If the electronic control unit  32  determines in step S 46  that the pitch angle DA is less than the second predetermined angle D 2 , then the electronic control unit  32  increases the response speed R and lowers the response speed Q in step S 47 . Then, the electronic control unit  32  proceeds to step S 44 . 
     In step S 44 , the electronic control unit  32  determines whether or not the predetermined period PX 1  has elapsed. For example, the electronic control unit  32  determines that the predetermined period PX 1  has elapsed in a case in which the elapsed period from the time at which the electronic control unit  32  determines in step S 41  that the vehicle speed V has become less than or equal to the first speed V 1  becomes greater than or equal to the predetermined period PX 1 . The electronic control unit  32  repeats the determination of step S 44  until the predetermined period PX 1  elapses. If the predetermined period PX 1  has elapsed, then the electronic control unit  32  proceeds to step S 45 . In step S 45 , the electronic control unit  32  returns the response speed R and the response speed Q to their original values. The process of step S 45  sets the response speed R and the response speed Q to the response speed R and the response speed Q prior to the change in step S 47 . For example, the electronic control unit  32  returns the response speed R and the response speed Q to the initial values QX and RX stored in the memory  34 . 
     If the electronic control unit  32  determines in step S 41  that the vehicle speed V is greater than the first speed V 1 , then the electronic control unit  32  proceeds to step S 48 . In step S 48 , the electronic control unit  32  determines whether or not the pitch angle DA is greater than the first predetermined angle DX 1 . If the electronic control unit  32  determines that the pitch angle DA is greater than the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 49 . In step S 49 , the electronic control unit  32  decreases the response speed R and increases the response speed Q. Then, the electronic control unit  32  proceeds to step S 50 . For example, the electronic control unit  32  decreases the response speed R to a value lower than the initial value RX of the response speed R that is stored beforehand in the memory  34 , and the electronic control unit  32  increases the response speed Q to a value higher than the initial value QX of the response speed Q that is stored beforehand in the memory  34 . The electronic control unit  32  sets the response speed R and the response speed Q to values differing from those set in step S 43 . For example, the response speed R set in step S 43  by the electronic control unit  32  is lower than the response speed R set in step S 49 , and the response speed Q set in step S 43  by the electronic control unit  32  is higher than the response speed Q set in step S 49 . 
     In step S 50 , the electronic control unit  32  determines whether or not a predetermined period PX 2  has elapsed. More specifically, the electronic control unit  32  determines that the predetermined period PX 2  has elapsed in a case in which the elapsed period from the time at which the electronic control unit  32  changes the response speeds R and Q in step S 49  becomes greater than or equal to the predetermined period PX 2 . Preferably, the predetermined period PX 2  is set in a range of one to ten seconds. In one example, the predetermined period PX 2  is set to three seconds. Preferably, the predetermined period PX 2  is stored beforehand in the memory  34 . The memory  34  is configured to allow the predetermined period PX 2  to be changed. For example, operation of the operation unit  14  or use of an external device changes the predetermined period PX 2  stored in the memory  34 . The electronic control unit  32  repeats the determination of step S 50  until the predetermined period PX 2  elapses. If the predetermined period PX 2  elapses, then the electronic control unit  32  proceeds to step S 51 . In step S 51 , the electronic control unit  32  returns the response speed R and the response speed Q to their original values. The process of step S 51  sets the response speed R and the response speed Q to the response speed R and the response speed Q prior to the change in step S 49 . For example, the electronic control unit  32  returns the response speed R and the response speed Q to the initial values QX and RX stored in the memory  34 . 
     If the electronic control unit  32  determines in step S 48  that the pitch angle DA is not greater than the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 52 . In step S 52 , the electronic control unit  32  determines whether or not the pitch angle DA is less than the second predetermined angle D 2 . If the electronic control unit  32  determines that the pitch angle DA is greater than or equal to the second predetermined angle D 2 , then the electronic control unit  32  ends the processing. Thus, in a case in which the bicycle  10  is on a road in which the pitch angle DA is less than or equal to the first predetermined angle DX 1  and greater than or equal to the second predetermined angle D 2 , the electronic control unit  32  ends the processing without changing the response speeds R and Q. 
     If the electronic control unit  32  determines that the pitch angle DA is less than the second predetermined angle D 2  in step S 52 , then the electronic control unit  32  proceeds to step S 53 . In step S 53 , the electronic control unit  32  increases the response speed R and decreases the response speed Q. Then, the electronic control unit  32  proceeds to step S 50 . For example, the electronic control unit  32  increases the response speed R to a value higher than the initial value RX of the response speed R that is stored beforehand in the memory  34  and decreases the response speed Q to a value lower than the initial value QX of the response speed Q that is stored beforehand in the memory  34 . For example, the response speed R set in step S 53  by the electronic control unit  32  is higher than the response speed R set in step S 49 , and the response speed Q set in step S 53  by the electronic control unit  32  is lower than the response speed Q set in step S 49 . 
     In step S 50 , the electronic control unit  32  determines whether or not the predetermined period PX 2  has elapsed. More specifically, the electronic control unit  32  determines that the predetermined period PX 2  has elapsed if the elapsed time from the time at which the response speeds R and Q are changed in step S 53  becomes greater than or equal to the predetermined period PX 2 . The electronic control unit  32  repeats the determination of step S 50  until the predetermined period PX 2  elapses. If the predetermined period PX 2  elapses, then the electronic control unit  32  proceeds to step S 51 . 
     Fourth Embodiment 
     With reference to  FIGS. 1, 12, and 13 , a fourth embodiment of the bicycle controller  30  will now be described. The fourth embodiment of the bicycle controller  30  is similar to the first embodiment of the bicycle controller  30  except in that a control is executed to change the output torque TA of the motor  22  in accordance with the inclination angle D. Same reference numerals are given to those components that are the same as the corresponding components of the first embodiment. Such components will not be described in detail. 
     In the present embodiment, the electronic control unit  32  shown in  FIG. 1  is configured to control the motor  22  in accordance with the manual driving force T in a riding mode. Further, the electronic control unit  32  controls the motor  22  in accordance with the manual driving force T. In the riding mode, the electronic control unit  32  controls the output torque TA of the motor  22  so that the output torque TA is less than or equal to a predetermined torque TY. The predetermined torque TY is changed in accordance with the inclination angle D of the bicycle  10 . The predetermined torque TY includes a first torque TY 1 . The first torque TY 1  is set in accordance with the output characteristics of the motor  22 . Further, the first torque TY 1  is set to a value that is less than the upper limit torque of the output torque TA of the motor  22  and in the proximity of the upper limit torque. 
     In a case in which the electronic control unit  32  controls the motor  22  in accordance with the manual driving force T, the electronic control unit  32  controls the output torque TA of the motor  22  so that the output torque TA is less than or equal to the first torque TY 1 . The first torque TY 1  is changed in accordance with the inclination angle D of the bicycle  10 . The memory  34  stores a fifth map that sets the relationship of the first torque TY 1  and the crank rotation speed N. The solid line L 31  in  FIG. 12  shows one example of the fifth map. Preferably, the first torque TY 1  is set for each riding mode. If the inclination angle D of the bicycle  10  increases on an uphill, then the electronic control unit  32  increases the first torque TY 1 . If the inclination angle D of the bicycle  10  increases on a downhill, then the electronic control unit  32  decreases the first torque TY 1 . 
     With reference to  FIG. 13 , motor control that changes the first torque TY 1  in accordance with the inclination angle D will now be described. The motor control is repeated in predetermined cycles as long as the electronic control unit  32  is supplied with power. 
     In step S 61 , the electronic control unit  32  determines whether or not the pitch angle DA is greater than the first predetermined angle DX 1 . If the electronic control unit  32  determines that the pitch angle DA is greater than the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 62 . In step S 62 , the electronic control unit  32  increases the first torque TY 1  and then proceeds to step S 63 . More specifically, the electronic control unit  32  switches the control of the motor  22  from a control that uses the map shown by the solid line L 31  in  FIG. 12  setting the relationship of the first torque TY 1  and the crank rotation speed N to a control that uses the map shown by the broken line L 32  in  FIG. 12  setting the relationship of the first torque TY 1  and the crank rotation speed N. 
     In step S 63 , the electronic control unit  32  determines whether or not the pitch angle DA is greater than the first predetermined angle DX 1 . As long as the electronic control unit  32  determines in step S 63  that the pitch angle DA is greater than the first predetermined angle DX 1 , the electronic control unit  32  repeats the determination of step S 63 . If the electronic control unit  32  determines in step S 63  that the pitch angle DA is less than or equal to the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 64  and returns the first torque TY 1  to its original value. More specifically, the electronic control unit  32  switches the control of the motor  22  using the map setting the relationship of the first torque TY 1  and the crank rotation speed N to the control executed prior to the switching in step S 62 . 
     If the electronic control unit  32  determines in step S 61  that the pitch angle DA is less than or equal to the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 65 . In step S 65 , the electronic control unit  32  determines whether or not the pitch angle DA is less than the second predetermined angle D 2 . If the electronic control unit  32  determines that the pitch angle DA is less than the second predetermined angle D 2 , then the electronic control unit  32  proceeds to step S 66 . In step S 66 , the electronic control unit  32  decreases the first torque TY 1  and proceeds to step S 67 . More specifically, the electronic control unit  32  switches the control of the motor  22  from a control that uses the map shown by the solid line L 31  in  FIG. 12  setting the relationship of the first torque TY 1  and the crank rotation speed N to a control that uses the map shown by the single-dashed line L 32  in  FIG. 12  setting the relationship of the first torque TY 1  and the crank rotation speed N. 
     In step S 67 , the electronic control unit  32  determines whether or not the pitch angle DA is less than the second predetermined angle D 2 . As long as the electronic control unit  32  determines in step S 67  that the pitch angle DA is less than the second predetermined angle D 2 , the electronic control unit  32  repeats the determination of step S 67 . If the electronic control unit  32  determines in step S 67  that the pitch angle DA is greater than or equal to the second predetermined angle D 2 , then the electronic control unit  32  proceeds to step S 64  and returns the first torque TY 1  to its original value. More specifically, the electronic control unit  32  switches the control of the motor  22  using the map setting the relationship of the first torque TY 1  and the crank rotation speed N to the control executed prior to the switching in step S 66 . 
     If there are multiple riding modes, in which the ratio of the motor output TM to the manual driving force T differs for each riding mode, and the electronic control unit  32  increases the first torque TY 1  in step S 62 , then the electronic control unit  32  preferably sets the first torque TY 1  to the maximum torque of the motor output TM in the riding mode in which the ratio of the motor output TM to the manual driving force T is the largest. If there are multiple riding modes, in which the ratio of the motor output TM to the manual driving force T differs for each riding mode, and the electronic control unit  32  decreases the first torque TY 1  in step S 66 , then the electronic control unit  32  preferably sets the first torque TY 1  to the maximum torque of the motor output TM in the riding mode in which the ratio of the motor output TM to the manual driving force T is the smallest. 
     Fifth Embodiment 
     With reference to  FIGS. 1, and 14 to 16 , a fifth embodiment of the bicycle controller  30  will now be described. The fifth embodiment of the bicycle controller  30  is similar to the first embodiment of the bicycle controller  30  except in that a control is executed to drive the motor  22  in accordance with the operation of the operation unit  14 . Same reference numerals are given to those components that are the same as the corresponding components of the first embodiment. Such components will not be described in detail. 
     In the present embodiment, the electronic control unit  32  is configured to switch between a riding mode and a walk mode in accordance with operation of the operation unit  14  shown in  FIG. 1 . The electronic control unit  32  controls the motor  22  in accordance with the operation of the operation unit  14 . More specifically, in a case in which the operation unit  14  is operated to drive the motor  22  in the walk mode, the electronic control unit  32  starts driving the motor  22  if the manual driving force T is zero. In a case in which the electronic control unit  32  controls the motor  22  in accordance with the operation of the operation unit  14 , the electronic control unit  32  controls the output torque TA of the motor  22  to be less than or equal to a second torque TY 2 . In a case in which the electronic control unit  32  controls the motor  22  in accordance with operation of the operation unit  14 , the electronic control unit  32  controls the vehicle speed V to be less than or equal to a predetermined vehicle speed V. The electronic control unit  32  changes the increasing speed of the output torque TA of the motor  22  in accordance with the inclination angle D of the bicycle  10 . If the inclination angle D of the bicycle  10  increases on an uphill, then the electronic control unit  32  increases the increasing speed of the output torque TA of the motor  22 . If the inclination angle D of the bicycle  10  increases on a downhill, then the electronic control unit  32  decreases the increasing speed of the output torque TA of the motor  22 . 
     With reference to  FIGS. 14 to 16 , the motor control in the walk mode will now be described. The motor control is repeated in predetermined cycles as long as the electronic control unit  32  is supplied with power. 
     In step S 71 , the electronic control unit  32  determines whether or not there is a start request for driving the motor  22  in the walk mode. More specifically, if the operation unit  14  is operated to drive the motor  22  in the walk mode and the manual driving force T is zero, then the electronic control unit  32  determines that there is a start request for driving the motor  22  in the walk mode. If the electronic control unit  32  determines that there is no start request for driving the motor  22  in the walk mode, then the electronic control unit  32  ends the processing. 
     If the electronic control unit  32  determines that there is a start request for driving the motor  22  in the walk mode, then the electronic control unit  32  proceeds to step S 72 . In step S 72 , the electronic control unit  32  determines whether or not the pitch angle DA is greater than the first predetermined angle DX 1 . If the electronic control unit  32  determines that the pitch angle DA is greater than the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 73 . In step S 73 , the electronic control unit  32  sets the increasing speed of the output torque TA to the first increasing speed and then proceeds to step S 77 . 
     If the electronic control unit  32  determines in step S 72  that the pitch angle DA is less than or equal to the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 74 . In step S 74 , then the electronic control unit  32  determines whether or not the pitch angle DA is less than the second predetermined angle D 2 . If the electronic control unit  32  determines that the pitch angle DA is less than the second predetermined angle D 2 , then the electronic control unit  32  proceeds to step S 75 . In step S 75 , the electronic control unit  32  sets the increasing speed of the output torque TA to the second increasing speed and then proceeds to step S 77 . 
     If the electronic control unit  32  determines in step S 74  that the pitch angle DA is greater than or equal to the second predetermined angle D 2 , then the electronic control unit  32  proceeds to step S 76 . In step S 76 , the electronic control unit  32  sets the increasing speed of the output torque TA to a third increasing speed and then proceeds to step S 77 . In  FIG. 16 , the broken line L 41  shows the output torque TA in a case in which the first increasing speed is set. The single-dashed line L 42  shows the output torque TA in a case in which the second increasing speed is set. The solid line L 43  shows the output torque TA in a case in which the third increasing speed is set. The first increasing speed is higher than the third increasing speed. The second increasing speed is lower than the third increasing speed. 
     In step S 77 , the electronic control unit  32  starts driving the motor  22  at the increasing speed set in step S 73 , S 75 , or S 76  and then proceeds to step S 78 . In step S 78 , the electronic control unit  32  determines whether or not the output torque TA is greater than or equal to the second torque TY 2 . The electronic control unit  32  repeats the determination of step S 78  until the output torque TA reaches the second torque TY 2 . The process of step S 78  increases the output torque TA to the second torque TY 2  as shown in  FIG. 16  by the broken line L 41 , the single-dashed line L 42 , or the solid line  43 . 
     If the electronic control unit  32  determines that the output torque TA is greater than or equal to the second torque TY 2 , then the electronic control unit  32  proceeds to step S 79 . In step S 79 , the electronic control unit  32  starts controlling the motor  22  in accordance with the vehicle speed V and then proceeds to step S 80 . In step S 80 , the electronic control unit  32  determines whether or not there is a drive termination request for the motor  22  in the walk mode. The electronic control unit  32  determines that there is a drive termination request for the motor  22  in the walk mode in any of the cases in which the operation unit  14  is no longer operated to drive the motor  22  in the walk mode, the operation unit  14  is operated to switch to the riding mode, and the manual driving force T becomes greater than zero. The electronic control unit  32  repeats the processes of steps S 79  and S 80  until determining that there is a drive termination request for the motor  22  in the walk mode. If the electronic control unit  32  determines that there is a drive termination request for the motor  22  in the walk mode, then the electronic control unit  32  in step S 81  stops driving the motor  22  in the walk mode and ends the processing. 
     Sixth Embodiment 
     Referring to  FIG. 17 , a sixth embodiment of the bicycle controller  30  will now be described. The sixth embodiment of the bicycle controller  30  is similar to the first embodiment of the bicycle controller  30  except in that a control is executed to change the response speeds R and Q as the bicycle starts to travel. Same reference numerals are given to those components that are the same as the corresponding components of the first embodiment. Such components will not be described in detail. 
     In the present embodiment, the electronic control unit  32  sets the response speeds R and Q so that the response speeds R and Q for a case during a predetermined period PX from the time at which the bicycle  10  starts to travel differs from the response speeds for a case in which the predetermined period PX has elapsed. In one example, the predetermined period PX is set to three seconds. The electronic control unit  32  sets the response speed Q for a case during the predetermined period PX from the time at which the bicycle  10  starts to travel to be higher than the response speed Q for a case in which the predetermined period PX has elapsed. 
     With reference to  FIG. 17 , motor control for changing the response speeds R and Q when the bicycle starts to travel will now be described. The motor control is repeated in predetermined cycles as long as the electronic control unit  32  is supplied with power. 
     In step S 91 , the electronic control unit  32  determines whether or not the bicycle  10  has started to travel. If the electronic control unit  32  determines that the bicycle  10  has not started to travel, then the electronic control unit  32  ends the processing. For example, the electronic control unit  32  determines that the bicycle  10  has started to travel if the vehicle speed V of the bicycle  10  changes from zero to greater than zero. Otherwise, the electronic control unit  32  determines that the bicycle  10  has not started to travel. If the electronic control unit  32  determines that the bicycle  10  has started to travel, then the electronic control unit  32  proceeds to step S 92 . In step S 92 , the electronic control unit  32  decreases the response speed R and increases the response speed Q. Then, the electronic control unit  32  proceeds to step S 93 . More specifically, the electronic control unit  32  decreases the response speed R to a value lower than the initial value RX of the response speed R that is stored beforehand in the memory  34  and increases the response speed Q to a value higher than the initial value QX of the response speed Q that is stored beforehand in the memory  34 . 
     In step S 93 , the electronic control unit  32  determines whether or not the predetermined period PX has elapsed. For example, if the period from the time at which the electronic control unit  32  determined in step S 91  that the bicycle  10  has started to travel is greater than or equal to the predetermined period PX, then the electronic control unit  32  determines that the predetermined period PX has elapsed. The electronic control unit  32  repeats the determination of step S 93  until the predetermined period PX elapses. If the electronic control unit  32  determines that the predetermined period PX has elapsed, then the electronic control unit  32  proceeds to step S 94 . In step S 94 , the electronic control unit  32  returns the response speed R and the response speed Q to their original values and then ends the processing. More specifically, the electronic control unit  32  returns the response speed R and the response speed Q to the initial values RX and QX stored beforehand in the memory  34 . 
     Seventh Embodiment 
     Referring to  FIGS. 1 and 18 , a seventh embodiment of the bicycle controller  30  will now be described. The seventh embodiment of the bicycle controller  30  is similar to the first embodiment of the bicycle controller  30  except in that a control is executed to change the response speeds R and Q in accordance with the vehicle speed V. Same reference numerals are given to those components that are the same as the corresponding components of the first embodiment. Such components will not be described in detail. 
     In the present embodiment, the electronic control unit  32  sets the response speeds R and Q so that the response speeds R and Q for a case in which the vehicle speed V of the bicycle  10  is less than or equal to the first speed V 1  differs from the response speeds R and Q for a case in which the vehicle speed V of the bicycle  10  exceeds the first speed V 1 . Preferably, the first speed V 1  is set to the vehicle speed V that allows for determination that the bicycle  10  has started to travel. In one example, the first speed V 1  is preferably set in the range from 1 to 10 km/h. In one example, the first speed V 1  is set to 3 km/h. The electronic control unit  32  sets the response speed Q for a case in which the vehicle speed V of the bicycle  10  is less than or equal to the first speed V 1  to be higher than the response speed Q for a case in which the vehicle speed V of the bicycle  10  exceeds the first speed V 1 . Further, the electronic control unit  32  sets the response speed R for a case in which the vehicle speed V of the bicycle  10  is less than or equal to the first speed V 1  to be lower than the response speed R for a case in which the vehicle speed V of the bicycle  10  exceeds the first speed V 1 . 
     Referring to  FIG. 18 , the motor control that changes the first torque TY 1  in accordance with the inclination angle D will now be described. The motor control is repeated in predetermined cycles as long as the electronic control unit  32  is supplied with power. 
     In step S 95 , the electronic control unit  32  determines whether or not the vehicle speed V is less than or equal to the first speed V 1 . If the electronic control unit  32  determines that the vehicle speed V is greater than the first speed V 1 , then the electronic control unit  32  ends the processing. If the electronic control unit  32  determines that the vehicle speed V is less than or equal to the first speed V 1 , then the electronic control unit  32  proceeds to step S 96 . In step S 96 , the electronic control unit  32  decreases the response speed R and increases the response speed Q. Then, the electronic control unit  32  proceeds to step S 97 . More specifically, the electronic control unit  32  decreases the response speed R to a value lower than the initial value RX of the response speed R that is stored beforehand in the memory  34  and increases the response speed Q to a value higher than the initial value QX of the response speed Q that is stored beforehand in the memory  34 . 
     In step S 97 , the electronic control unit  32  determines whether or not the vehicle speed V is less than or equal to the first speed V 1 . The electronic control unit  32  repeats the determination of step S 97  until the vehicle speed V becomes greater than the first speed V 1 . If the electronic control unit  32  determines that the vehicle speed V is greater than the first speed V 1 , then the electronic control unit  32  proceeds to step S 98  and returns the response speed R and the response speed Q to their original values. The electronic control unit  32  then ends the processing. More specifically, the electronic control unit  32  returns the response speed R and the response speed Q to the initial values RX and QX stored beforehand in the memory  34 . 
     Modified Examples 
     The present invention is not limited to the foregoing embodiment and various changes and modifications of its components can be made without departing from the scope of the present invention. Also, the components disclosed in the embodiment can be assembled in any combination for embodying the present invention. For example, some of the components can be omitted from all components disclosed in the embodiment. Further, several of the modified examples described below can be combined. 
     The motor control of  FIG. 2  can be modified to the motor control shown in  FIG. 19 . In the motor control of  FIG. 19 , in step S 11 , the electronic control unit  32  computes the manual driving force T and then proceeds to step S 13  without determining the riding mode. In step S 13 , the electronic control unit  32  computes the corrected driving force TX based on the first map, the inclination angle D, the crank rotation speed N, and the manual driving force T. Then, the electronic control unit  32  proceeds to step S 14 . In this modified example, the bicycle controller  30  functions in only one riding mode and stores only the first map. The bicycle controller  30  does not store the second map. 
     The motor control of  FIG. 2  can be modified to the motor control shown in  FIG. 20 . In the motor control of  FIG. 20 , in step S 11 , the electronic control unit  32  computes the manual driving force T and then proceeds to step S 17  without determining the riding mode. In step S 17 , the electronic control unit  32  computes the corrected driving force TX based on the second map, the inclination angle D, the crank rotation speed N, and the manual driving force T. Then, the electronic control unit  32  proceeds to step S 14 . In this modified example, the bicycle controller  30  functions in only one riding mode and stores only the second map. The bicycle controller  30  does not store the second map. 
     The motor control of  FIG. 2  can be modified to the motor control shown in  FIG. 21 . Instead of correcting the manual driving force T, the correction unit  48  is configured to correct the motor output TM, which is computed based on the manual driving force T by the output computation unit  50 . In the motor control of  FIG. 21 , in step S 21 , the electronic control unit  32  computes the manual driving force T. In step S 22 , the electronic control unit  32  multiplies the manual driving force T by a predetermined value to compute the motor output TM. In step S 23 , the electronic control unit  32  determines whether or not the present riding mode is the first mode. If the electronic control unit  32  determines that the riding mode is the first mode, then the electronic control unit  32  proceeds to step S 24 . In step S 24 , the electronic control unit  32  computes a corrected output TD based on the first map, the inclination angle D, the crank rotation speed N, and the motor output TM. Then, the electronic control unit  32  proceeds to step S 25 . If the electronic control unit  32  determines in step S 23  that the present riding mode is not the first mode, that is, the present mode is the second mode, then the electronic control unit  32  proceeds to step S 27 . In step S 27 , the electronic control unit  32  computes the corrected output TD based on the second map, the inclination angle D, the crank rotation speed N, and the motor output TM. 
     In step S 25 , the electronic control unit  32  determines whether or not the manual driving force T is decreasing. If the electronic control unit  32  determines in step S 25  that the manual driving force T is decreasing, then the electronic control unit  32  proceeds to step S 26  and controls the motor  22  based on the corrected output TD. Then, after a predetermined cycle, the electronic control unit  32  starts the process again from step S 21 . 
     If the electronic control unit  32  determines in step S 25  that the manual driving force T is not decreasing, then the electronic control unit  32  proceeds to step S 28  and determines whether or not the motor output TM is greater than the corrected output TD. If the electronic control unit  32  determines in step S 28  that the motor output TM is greater than the corrected output TD, then the electronic control unit  32  proceeds to step S 29  and controls the motor  22  based on the motor output TM. Then, after a predetermined cycle, the electronic control unit  32  starts the process again from step S 21 . 
     If the electronic control unit  32  determines in step S 28  that the motor output TM is less than or equal to the corrected output TD, then the electronic control unit  32  proceeds to step S 26  and controls the motor  22  based on the corrected output TD. Then, after a predetermined cycle, the electronic control unit  32  starts the process again from step S 21 . 
     In the first and second embodiments, the electronic control unit  32  can be configured to change the response speed R in accordance with the inclination angle D regardless of the crank rotation speed N. More specifically, the electronic control unit  32  can set the time constant K using the first map and the second map that include only the relationship of the inclination angle D and the time constant K. That is, the electronic control unit  32  sets the time constant K in accordance with the inclination angle D regardless of the crank rotation speed N. 
     In the first and second embodiments, the electronic control unit  32  sets the time constant K using the first map or the second map. Instead of using a map, the electronic control unit  32  can use a computation equation to set the time constant K. In this case, the memory  34  stores computation equations corresponding to riding modes such as equations (1) and (2), which are described above. 
     In the first and second embodiments, in the first mode and the second mode, the electronic control unit  32  changes the response speed R in a stepped manner in accordance with the inclination angle D. However, the response speed R can be changed in a continuous manner in accordance with the inclination angle D. In this case, for example, coefficients A1, A2, and B, which are used in equations (1) and (2), are calculated from functions that change in accordance with the inclination angle D. 
     In the first embodiment, if the manual driving force T increases on a downhill, then the electronic control unit  32  can decrease the response speed R as the inclination angle D of the downhill increases. 
     In the second embodiment, the increase rate of the manual driving force T can be set to be lower than the increase rate of the manual driving force T in a case in which the response speed Q is set to the initial value QX. In this case, as the response speed Q increases from the initial value QX, the increase rate of the manual driving force T approaches the increase rate of the corrected driving force TX. As the response speed Q decreases from the initial value QX, the increase rate of the corrected driving force TX is retarded from the increase rate of the manual driving force T. In this modified example, in a case in which the electronic control unit  32  increases the manual driving force T, the electronic control unit  32  can change the response speed Q by changing the time constant K instead of changing the response speed Q by adding the corrected value CX to the manual driving force T or multiplying the manual driving force T by the corrected value CX. More specifically, the time constant K corresponding to the initial value QX is set to a value that is greater than zero. In this case, for example, the increase rate of the motor output TM during period X 2  from time t 30  to time t 31  in the timing chart C of  FIG. 8  becomes closer to the increase rate of the manual driving force T than the increase rate of the motor output TM during period X 2  from time t 31  to time t 32 . Further, the increase rate of the motor output TM during period X 2  from time t 41  to time t 42  in the timing chart C of  FIG. 9  becomes closer to the increase rate of the manual driving force T than the increase rate of the motor output TM during period X 2  from time t 41  to time t 42 . 
     In the second embodiment, one of the first mode and the second mode can be omitted. For example, in a case in which the second mode is omitted, in the motor control of  FIG. 7 , the electronic control unit  32  can omit steps S 32 , S 38 , S 39  and S 40 . In this case, after performing the process of step S 31 , the electronic control unit  32  proceeds to step S 33 . In a case in which the first mode is omitted, in the motor control of  FIG. 7 , the electronic control unit  32  can omit steps S 32 , S 33 , S 34  and S 37 . In this case, after performing the process of step S 31 , the electronic control unit  32  proceeds to step S 38 . 
     In the third embodiment, instead of performing the determination of step S 44 , the electronic control unit  32  can determine whether or not the vehicle speed V is greater than or equal to a second speed V 2 . In one example, the second speed V 2  is set to 15 km/h. The electronic control unit  32  repeats the determination of step S 44  until the vehicle speed V becomes greater than or equal to the second speed V 2 . If the vehicle speed V becomes greater than or equal to the second speed V 2 , then the electronic control unit  32  proceeds to step S 45 . 
     In the third embodiment, instead of the determination of step S 50 , the electronic control unit  32  can determine whether or not the vehicle speed V is greater than or equal to the second speed V 2 . If the vehicle speed V becomes greater than or equal to the second speed V 2 , then the electronic control unit  32  proceeds to step S 51 . 
     In the third embodiment, one of the response speed R and the response speed Q for a case during the predetermined period PX 1  from the time at which the bicycle  10  starts to travel can be different from that for a case in which the predetermined period PX 1  has elapsed. More specifically, in at least one of step S 43  and step S 47  in  FIG. 10 , the electronic control unit  32  can change just one of the response speed R and the response speed Q. 
     In the third embodiment, at least one of step S 44  and step S 50  can be omitted from the flowchart of  FIGS. 10 and 11 . In a case in which step S 44  is omitted, if the electronic control unit  32  performs step S 43  or step S 47 , then the electronic control unit  32  ends the processing. In this case, if the electronic control unit  32  determines in step S 46  that the pitch angle DA is greater than or equal to the second predetermined angle D 2 , then the electronic control unit  32  can proceed to step S 45 . In a case in which step S 50  is omitted, if the electronic control unit  32  performs step S 49  or step S 53 , then the electronic control unit  32  ends the processing. In this case, if the electronic control unit  32  determines in step S 52  that the pitch angle DA is greater than or equal to the second predetermined angle D 2 , then the electronic control unit  32  can proceed to step S 51 . 
     In the third embodiment, the electronic control unit  32  can set the response speeds R and Q for a case in which the vehicle speed V of the bicycle  10  is less than or equal to the first speed V 1  to be different from the response speeds R and Q for a case in which the vehicle speed V of the bicycle  10  exceeds the first speed V 1 . 
     In the third embodiment and its modified examples, steps S 41  and S 48  to S 53  can be omitted from the flowchart of  FIGS. 10 and 11 . 
     In the third embodiment, if the electronic control unit  32  sets the response speeds R and Q for a case in which the vehicle speed V of the bicycle  10  is less than or equal to the first speed V 1  to be different from the response speeds R and Q for a case in which the vehicle speed V of the bicycle  10  exceeds the first speed V 1 , then the electronic control unit  32  can change and differ just one of the response speed R and the response speed Q. For example, in steps S 43  and S 47  of  FIG. 10 , the electronic control unit  32  changes only one of the response speed R and the response speed Q. In steps S 49  and S 53  of  FIG. 11 , the electronic control unit  32  changes only one of the response speed R and the response speed Q. 
     In the third embodiment and its modified examples, in a case in which the electronic control unit  32  changes the response speeds R and Q in accordance with the pitch angle DA of the bicycle  10 , the electronic control unit  32  can change just one of the response speed R and the response speed Q. For example, in at least one of steps S 43 , S 47 , S 49  and S 53  of  FIGS. 10 and 11 , only one of the response speed R and the response speed Q is changed. 
     In the third embodiment and its modified examples, step S 46  and S 47  can be omitted from the flowchart of  FIG. 10 . In this case, if the electronic control unit  32  determines in step S 42  that the pitch angle DA is less than or equal to the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 44 . 
     In the third embodiment and its modified examples, steps S 42  and S 43  can be omitted from the flowchart of  FIG. 10 . In this case, if the electronic control unit  32  determines in step S 41  that the vehicle speed V is less than or equal to the first speed V 1 , then the electronic control unit  32  proceeds to step S 46 . 
     In the third embodiment and its modified examples, steps S 52  and S 53  can be omitted from the flowchart of  FIG. 11 . In this case, if the electronic control unit  32  determines in step S 48  that the pitch angle DA is less than or equal to the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 50 . 
     In the third embodiment and its modified examples, steps S 48  and S 49  can be omitted from the flowchart of  FIG. 11 . In this case, if the electronic control unit  32  determines in step S 41  that the vehicle speed V is greater than the first speed V 1 , then the electronic control unit  32  proceeds to step S 52 . 
     In the third embodiment and its modified examples, the flowchart of  FIG. 10  can be ended in a case in which the process of step S 47  ends. Further, the flowchart of  FIGS. 10 and 11  can be ended in a case in which the process of step S 53  ends. 
     In the fourth embodiment, steps S 65 , S 66  and S 67  can be omitted from the flowchart of  FIG. 13 . In this case, if the electronic control unit  32  determines in step S 61  that the pitch angle DA is less than or equal to the first predetermined angle DX 1 , then the electronic control unit  32  ends the processing. 
     In the fourth embodiment, steps S 61 , S 62  and S 63  can be omitted from the flowchart of  FIG. 13 . In this case, if the electronic control unit  32  is supplied with power, then the electronic control unit  32  performs the process of step S 65 . 
     In the fifth embodiment, steps S 74  and S 75  can be omitted from the flowchart of  FIG. 14 . In this case, if the electronic control unit  32  determines in step S 72  that the pitch angle DA is less than or equal to the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 76 . 
     In the fifth embodiment, step S 72  and step S 73  can be omitted from the flowchart of  FIG. 14 . In this case, if the electronic control unit  32  determines in step S 71  that there is a start request for driving the motor  22  in the walk mode, the electronic control unit  32  proceeds to step S 74 . 
     In the fifth embodiment and its modified examples, the second torque TY 2  can be changed in accordance with the inclination angle D of the bicycle  10 . In one example, the electronic control unit  32  increases the second torque TY 2  if the inclination angle of the bicycle  10  increases on an uphill. If the inclination angle D of the bicycle  10  increases on a downhill, then the electronic control unit  32  decreases the second torque TY 2 . For example, as shown in  FIG. 22 , the electronic control unit  32  performs step S 82  instead of step S 73  of  FIG. 14 , step S 83  instead of step S 75  of  FIG. 14 , and step S 84  instead of step S 76  of  FIG. 14 . In step S 82 , the electronic control unit  32  sets the increasing speed of the output torque TA to the first increasing speed and sets the second torque TY 2  to a first value TZ 1 . In step S 83 , the electronic control unit  32  sets the increasing speed of the output torque TA to the second increasing speed and sets the second torque TY 2  to a second value TZ 2 . In step S 84 , the electronic control unit  32  sets the increasing speed of the output torque TA to the third increasing speed and sets the second torque TY 2  to a third value TZ 3 . The first value TZ 1  is greater than the third value TZ 3 . The second value TZ 2  is less than the third value TZ 3 . Thus, if the pitch angle DA is greater than the first predetermined angle DX 1 , then the electronic control unit  32  controls the motor  22  to become less than or equal to the second torque TY 2 , which is greater than for a case in which the pitch angle DA is greater than or equal to the second predetermined angle D 2  and less than or equal to the first predetermined angle DX 1 . If the pitch angle DA is less than the second predetermined angle D 2 , then the electronic control unit  32  controls the motor  22  to become less than or equal to the second torque TY 2 , which is less than for a case in which the pitch angle DA is greater than or equal to the second predetermined angle D 2  and less than or equal to the first predetermined angle DX 1 . 
     In the modified example shown in  FIG. 22 , the process for changing the output torque TA can be omitted in at least one of steps S 82 , S 83 , and S 84 . In this case, the increasing speed of the output torque TA is constant regardless of the inclination angle D of the bicycle  10 . 
     In the modified example shown in  FIG. 22 , steps S 74  to S 83  can be omitted from the flowchart. In this case, if the electronic control unit  32  determines in step S 72  that the pitch angle DA is less than or equal to the first predetermined angle DX 1 , then the electronic control unit  32  proceeds to step S 84 . 
     In the modified example shown in  FIG. 22 , steps S 72  and S 82  can be omitted from the flowchart. In this case, if the electronic control unit  32  determines that there is a start request for driving the motor  22  in the walk mode, then the electronic control unit  32  proceeds to step S 74 . 
     In the fifth embodiment, the electronic control unit  32  can change the increasing speed of the output torque TA of the motor  22  in accordance with the change amount of the inclination angle D of the bicycle  10 . In one example, if the increasing speed of the inclination angle D of the bicycle  10  on an uphill increases, then the electronic control unit  32  increases the increasing speed of the output torque TA of the motor  22 . If the increasing speed of the inclination angle D of the bicycle  10  on a downhill increases, then the electronic control unit  32  decreases the increasing speed of the output torque TA of the motor  22 . For example, after the electronic control unit  32  sets the increasing speed of the output torque TA in step S 73 , S 75  or step S 76  of  FIG. 14 , the electronic control unit  32  proceeds to step S 85 , which is shown in  FIG. 23 . In step S 85 , the electronic control unit  32  determines whether or not the pitch angle DA has become greater than zero and whether or not the increasing speed of the pitch angle DA has increased. If the electronic control unit  32  determines that the pitch angle DA is greater than zero and that the increasing speed of the pitch angle DA has increased, then the electronic control unit  32  proceeds to step S 86 . In step S 86 , the electronic control unit  32  increases the increasing speed of the output torque TA and then proceeds to step S 78 . In a case in which the electronic control unit  32  in step S 85  gives at least one of a determination that the pitch angle DA is less than or equal to zero and a determination that the increasing speed of the pitch angle DA has not increased, the electronic control unit  32  proceeds to step S 87 . In step S 87 , the electronic control unit  32  determines whether or not the pitch angle DA is less than zero and whether or not the decreasing speed of the pitch angle DA has increased. If the electronic control unit  32  determines that the pitch angle DA is less than zero and that the decreasing speed of the pitch angle DA has increased, then the electronic control unit  32  proceeds to step S 88 . In step S 88 , the electronic control unit  32  decreases the increasing speed of the output torque TA and proceeds to step S 78 . In step S 78 , the electronic control unit  32  repeats the processes from step S 85  until the output torque TA becomes greater than or equal to the second torque TY 2 . If the electronic control unit  32  determines in step S 78  that the output torque TA has become greater than or equal to the second torque TY 2 , then the electronic control unit  32  proceeds to step S 79 . If the electronic control unit  32  in step S 87  gives at least one of a determination that the pitch angle DA is zero or greater and a determination that the decreasing speed of the pitch angle DA has not increased, then the electronic control unit  32  proceeds to step S 78 . 
     In the modified example shown in  FIG. 23 , steps S 87  and S 88  can be omitted from the flowchart. In this case, if the electronic control unit  32  in step S 85  gives at least one of a determination that the pitch angle DA is zero or less and a determination that the increasing speed of the pitch angle DA has not increased, then the electronic control unit  32  proceeds to step S 78 . 
     In the modified example shown in  FIG. 23 , steps S 85  and S 86  can be omitted from the flowchart. In this case, the electronic control unit  32  performs the process of step S 77  and then proceeds to step S 87 . 
     In the sixth embodiment, the electronic control unit  32  does not have to change the response speed R. More specifically, in step S 92  of  FIG. 17 , the electronic control unit  32  changes the response speed Q but does not change the response speed R. 
     In the sixth embodiment, the electronic control unit  32  can change the response speeds R and Q after the electronic control unit  32  is supplied with power and before the bicycle  10  starts to travel. For example, in the flowchart of  FIG. 17 , step S 91  and step S 92  are reversed. In this case, if the bicycle  10  stops, then the electronic control unit  32  can perform the process of step S 92 . The electronic control unit  32  proceeds to step S 91  as the bicycle  10  starts to travel. If the electronic control unit  32  determines in step S 91  that the bicycle  10  has started to travel, then the electronic control unit  32  proceeds to step S 93 . 
     In the seventh embodiment, the electronic control unit  32  does not have to change the response speed R. More specifically, in step S 96  of  FIG. 18 , the electronic control unit  32  changes the response speed Q but does not change the response speed R. 
     In the seventh embodiment, the electronic control unit  32  can change the response speeds R and Q after the electronic control unit  32  is supplied with power and before the vehicle speed V becomes greater than zero and less than or equal to the first speed V 1 . For example, in the flowchart of  FIG. 18 , step S 95  and step S 96  can be reversed. In this case, if the bicycle  10  stops, then the electronic control unit  32  can perform the process of step S 96 . If the electronic control unit  32  determines in step S 95  that the vehicle speed V is less than or equal to the first speed V 1 , then the electronic control unit  32  proceeds to step S 97 . 
     The electronic control unit  32  can change the response speeds R and Q in accordance with changes in the inclination angle D of the bicycle  10 . In a case in which the increasing speed of the inclination angle D of the bicycle  10  increases on an uphill, the electronic control unit  32  increases the response speed Q if the manual driving force T increases on an uphill. In a case in which the increasing speed of the inclination angle D of the bicycle  10  increases on an uphill, the electronic control unit  32  decreases the response speed R. For example, the electronic control unit  32  executes the control shown in  FIG. 24 . In step S 101 , the electronic control unit  32  determines whether or not the pitch angle DA is greater than zero and the increasing speed of the pitch angle DA has increased. If the electronic control unit  32  determines that the pitch angle DA is greater than zero and that the increasing speed of the pitch angle DA has increased, then the electronic control unit  32  proceeds to step S 102 . In step S 102 , the electronic control unit  32  decreases the response speed R and increases the response speed Q. Then, the electronic control unit  32  ends the processing. If the electronic control unit  32  in step S 101  gives at least one of a determination that the pitch angle DA is zero or less and a determination that the increasing speed of the pitch angle DA has not increased, then the electronic control unit  32  proceeds to step S 103 . In step S 103 , the electronic control unit  32  determines whether or not the pitch angle DA is less than zero and whether or not the decreasing speed of the pitch angle DA has increased. If the electronic control unit  32  determines that the pitch angle DA is less than zero and that the decreasing speed of the pitch angle DA has increased, then the electronic control unit  32  proceeds to step S 104 . In step S 104 , the electronic control unit  32  increases the response speed R and decreases the response speed Q. If the electronic control unit  32  in step S 103  gives at least one of a determination that the pitch angle DA is zero or greater and a determination that the decreasing speed of the pitch angle DA is not increasing, then the electronic control unit  32  ends the processing without changing the response speeds R and Q. In this modified example, after changing the response speeds R and Q in step S 102  and step S 104 , the electronic control unit  32  can return the response speeds R and Q to their original values after a predetermined period. 
     In the modified example shown in  FIG. 24 , step S 103  and step S 104  can be omitted from the flowchart. In this case, if the electronic control unit  32  in step S 101  gives at least one of a determination that the pitch angle DA is zero or less and a determination that the increasing speed of the pitch angle DA is not increasing, then the electronic control unit  32  ends the processing. 
     In the modified example shown in  FIG. 24 , steps S 101  and S 102  can be omitted from the flowchart. In this case, the electronic control unit  32  performs the process of step S 103  if the electronic control unit  32  is supplied with power. 
     If the inclination angle D of the bicycle  10  changes from an angle corresponding to an uphill to a third angle DX 3  or greater that corresponds to a downhill during a first period, then the electronic control unit  32  can decrease the response speed Q if the manual driving force T increases. If the inclination angle D of the bicycle  10  changes from an angle corresponding to an uphill to the third angle DX 3  or greater that corresponds to a downhill during the first period, then the electronic control unit  32  can increase the response speed R. Preferably, the first period can be set to a range of one to ten seconds. In one example, the first period is set to three seconds. Preferably, the first period is stored beforehand in the memory  34 . The memory  34  is configured to allow the first period to be changed. For example, the operation of the operation unit  14  or the use of an external device changes the first period stored in the memory  34 . For example, the electronic control unit  32  executes the control shown in  FIG. 25 . In step S 105 , the electronic control unit  32  determines whether or not the pitch angle DA has changed from an angle greater than zero to the third angle DX 3  or less that is less than zero. If the electronic control unit  32  determines that the pitch angle DA has changed from an angle greater than zero to the third angle DX 3  or less that is less than zero, then the electronic control unit  32  proceeds to step S 106 . In step S 106 , the electronic control unit  32  increases the response speed R and decreases the response speed Q. Then, the electronic control unit  32  ends the processing. If the electronic control unit  32  determines in step S 105  that the pitch angle DA has not changed from an angle greater than zero to the third angle DX 3  or less that is less than zero, then the electronic control unit  32  ends the processing without changing the response speeds R and Q. In this modified example, after changing the response speeds R and Q in step S 106 , the electronic control unit  32  can return the response speeds R and Q to their original values after a predetermined period. In the flowchart of  FIG. 25 , the electronic control unit  32  does not have to change the response speed R. 
     The electronic control unit  32  can obtain the inclination angle D using the Global Positioning System (GPS) and map information including altitude information. Further, the electronic control unit  32  can include an altitude sensor that detects the atmospheric pressure. In this case, the electronic control unit  32  can accurately obtain the inclination angle D using the output of the altitude sensor in addition to the GPS information. An inclination detector can include a GPS receiver, a memory that stores map information, and an altitude sensor. Information of the inclination angle D obtained by the GPS can be input to the electronic control unit  32 , for example, via a cycle computer, a smartphone, or the like. The rider can also input the inclination angle D to the electronic control unit  32 . 
     The low-pass filter  52  can be replaced by a moving average filter. As long as the response speed R of the motor  22  with respect to a change in the manual driving force T can be changed, any structure can be employed. 
     The electronic control unit  32  can compute the inclination angle D based on the manual driving force T and the crank rotation speed N. In this case, for example, the electronic control unit  32  computes a large pitch angle DA if the manual driving force T is high and the crank rotation speed N is low. More specifically, the electronic control unit  32  determines that the inclination angle D on an uphill is large when the manual driving force T is high and the crank rotation speed N is low and determines that the inclination angle D on a downhill is large when the manual driving force T is low and the crank rotation speed N is high. Further, in this modified example, the inclination angle D can be computed using the speed of the bicycle  10  in addition to the manual driving force T and the crank rotation speed N. 
     The electronic control unit  32  can estimate the crank rotation speed N using the speed of the bicycle  10 . For example, the electronic control unit  32  can estimate the crank rotation speed N using the tire diameter and the gear ratio of the bicycle  10 .