Patent Publication Number: US-2015066274-A1

Title: Manually propelled vehicle

Description:
FIELD OF INVENTION 
     The present invention generally relates to a manually propelled vehicle such as ambulatory assist vehicles, baby carriages, dollies, wheelchairs, and the like. 
     BACKGROUND ART 
     In recent years, the development of manually propelled vehicles as, for example, ambulatory assist vehicles in order to support elderly people with a weak physique or people with trouble walking, has progressed. Further, the installing of a manual assistive function, a so-called electromotor assist function, has been studied. 
     Patent Literature 1 discloses a technology according to an ambulatory assist vehicle as a conventional art that relates to an ambulatory assist vehicle. This ambulatory assist vehicle is capable of setting movement resistance freely when moving rearward or turning and is capable of automatically switching the movement characteristics of the ambulatory assist vehicle in accordance with a moving state by a user. 
     PATENT LITERATURE  
     [Patent Literature 1] Japanese Patent Publication No. 2898969 
     In practice, a manually propelled vehicle comprising manual assistive functions, a sensing method to detect an operation intent of a user and an electromotor assisting method to reflect such detected result in the manual assisting function have not been established. There is room for improving the operability of manual propelled vehicles. 
     For example, an acting force applied in a vertical direction of a manually propelled vehicle is not taken into account in the conventional technology described in Patent Literature 1. Accordingly, it is possible that the electromotor assist function of the manually propelled vehicle may malfunction when, for example, a user hooks a bag or the like on the grip where the user holds or the user lifts up the grip. The conventional technology described above gives no consideration to such safety problems. 
     SUMMARY OF THE INVENTION 
     One or more embodiments of the present invention provide a manual propelled vehicle that can improve safety by preventing an assist operation unintended by a user and can perform appropriate human power assistance. 
     According to one or more embodiments, a manually propelled vehicle may comprise a vehicle body, a wheel for moving the vehicle body, a grip attached to the vehicle body, a grip sensor that detects a pressure applied to the grip, a grip state detector that detects a grip state of the grip based on information acquired from the grip sensor, and a wheel driver that drives the wheel when the grip state detector detects a predetermined grip state. 
     For example, according to one or more embodiments, the manually propelled vehicle may detect the grip state of the grip based on a pressure applied to the grip. At that time, the grip state detector may detect a predetermined grip state, which is the grip state when the user grips the grip. When the user grips the grip, the wheel may be driven and unintended assist operation by a user may be prevented. Therefore, safety can be improved. 
     Further, according to one or more embodiments, the grip state detector may: detect a distribution and an area of an applied pressure region detected by the grip sensor, determine whether the distribution and the area of the applied pressure region correspond to a predetermined condition, and detect the predetermined grip state when the grip state detector determines that the distribution and the area of the applied pressure region correspond to the predetermined condition. 
     For example, according to one or more embodiments, the manually propelled vehicle may determine the grip state of the user on the grip based on a distribution and an area of an applied pressure region of the grip. Accordingly, the manually propelled vehicle can distinguish whether the user gripped the grip to use the manually propelled vehicle as human power assistance or, for example, whether the user hooked a bag on the grip. According to one or more embodiments, when the bag is hooked on the grip, the wheel is not driven and unintended assist operation by the user can be prevented. Therefore, safety can be improved. 
     Further, according to one or more embodiments, the grip may have a bar shape that extends in a left and right direction and that intersects an advancing direction of the manually propelled vehicle, and the grip sensor may be a plurality of grip sensors circumferentially disposed on the grip. Each of the plurality of grip sensors may have a band shape that extends in the left and right direction, and when the distribution of the applied pressure region is concentrated in an upper local part of the grip and the area of the applied pressure region does not exceed a predetermined value, the grip state detector may determine that the distribution and the area of the applied pressure region do not correspond to the predetermined condition. 
     For example, according to one or more embodiments, the manually propelled vehicle may distinguish the applied pressure state that concentrates at the top local part in the width direction of the grip; in other words, the handle portion of a bag, for example, may be hooked on the grip. Accordingly, the manually propelled vehicle may determine that the user is not gripping the grip and unintended assist operation unintended by the user can be prevented. 
     Furthermore, according to one or more embodiments, the grip may have a bar shape that extends in a left and right direction and that intersects an advancing direction of the manually propelled vehicle, and the grip sensor may be a plurality of grip sensors circumferentially disposed on the grip. When the distribution of the applied pressure region is concentrated in a lower local part of the grip, the grip state detector may determine that the distribution and the area of the applied pressure region do not correspond to the predetermined condition. 
     For example, according to one or more embodiments, the manually propelled vehicle may distinguish the applied pressure state that concentrates at the lower part of the grip. That is, the user, for example, is attempting to lift up the grip. Accordingly, the manually propelled vehicle may determine that the user is not gripping the grip to use the manually propelled vehicle as the normal human-power assistance, and the assist operation unintended by the user can be prevented. 
     Moreover, according to one or more embodiments, the manually propelled vehicle may further comprise a user location sensor that detects a location of the user, wherein, the wheel driver does not drive the wheel when the user location sensor does not detect the location of the user. 
     For example, according to one or more embodiments, the manually propelled vehicle may detect the location of the user in addition to detecting the grip state to the grip. As a result, the manually propelled vehicle can distinguish, for example, whether or not only bag or the like is existed by being hooked on the grip, or whether the user also exists near the grip. Further, there is a possibility that the predetermined grip state, which may be set in advance by the user, may be detected depending on how the bag or the like is hooked on the grip even though the user is not gripping the grip. However, according to one or more embodiments, because the wheel is not driven when the location of the user cannot be detected, the assist operation unintended by the user can be more accurately prevented. 
     With a manually propelled vehicle according to one or more embodiments of the present invention, safety can be improved by preventing an assist operation unintended by a user and can perform appropriate human power assistance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a manually propelled vehicle according to one or more embodiments of a first example of the present invention. 
         FIG. 2  is a side view illustrating the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 3  is a plan view illustrating the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 4  is a plan view illustrating a grip of the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 5  is a block diagram of the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 6  is a schematic diagram illustrating a configuration of a wheel driver and a wheel of the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 7  is a block diagram illustrating the configuration of the wheel driver of the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 8  is a perspective view illustrating a configuration of a grip sensor of the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 9  is a vertical cross-sectional view illustrating a section of the grip sensor of the grip of the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 10  is a perspective view illustrating a state when a user holds the grip of the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 11  is an exploded view schematically illustrating a pressure distribution of the grip sensor when the user holds the grip of the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 12  is a perspective view illustrating a state when a bag is hooked on the grip of the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 13  is an exploded view schematically illustrating a pressure distribution of the grip sensor when a bag is hooked on the grip of the manually propelled vehicle according to one or more embodiments of the first example of the present invention. 
         FIG. 14  is a perspective view illustrating a state when a user is trying to lift up the grip of the manually propelled vehicle according to one or more embodiments of a second example of the present invention. 
         FIG. 15  is an exploded view schematically illustrating a pressure distribution of the grip sensor when the user is trying to lift up the grip of the manually propelled vehicle according to one or more embodiments of the second example of the present invention. 
         FIG. 16  is a side view of a manually propelled vehicle according to one or more embodiments of a third example of the present invention. 
         FIG. 17  is a block diagram of the manually propelled vehicle according to one or more embodiments of the third example of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     One or more embodiments of the present invention are described in detail below, with reference to the drawings. All numbers, shapes, materials, configuring elements, locations of configuring elements, modes of connection, steps, orders of steps, and so on are no more than examples and do not, in anyway, limit the scope of the claims that specify the present invention. Hence, the specific configurations described are not necessarily required, and are merely presented as examples and illustrations. 
     FIRST EXAMPLE 
     First, an outline of the configuration of a manually propelled vehicle according to one or more embodiments of the present invention will be described with reference to  FIG. 1  to  FIG. 5 .  FIG. 1 ,  FIG. 2 , and  FIG. 3  are respectively a front view, a side view, and a plan view of the manually propelled vehicle.  FIG. 4  is a plan view of a grip of the manually propelled vehicle, and  FIG. 5  is a block diagram of the manually propelled vehicle. In the following descriptions, as illustrated in  FIGS. 1 to 4 , descriptions are given where the advancing direction of the manually propelled vehicle is the x direction, a direction where the grip of the manually propelled vehicle extends is the y direction, and the vertical direction of the manually propelled vehicle is the z direction. The x direction, y direction, and z direction illustrated in  FIG. 8  also indicate the same directions. 
     According to one or more embodiments, the manually propelled vehicle  1  illustrated in  FIG. 1  to  FIG. 3  may be an ambulatory assist vehicle, a so-called walker that assists walking of a user, mainly elderly with a weak lower body and is also used as a basket for carrying baggage and a seat for resting. The manually propelled vehicle  1  may comprise a vehicle body  10 , a grip  20 , a wheel  30 , a seat  40 , a backrest  50 , a user interface  60 , a sensor  70 , an electromotor  80 , a power supply  90 , and a controller  100 . 
     The vehicle body  10  may be a chassis of the manually propelled vehicle  1  on which the components  20  to  100  listed above may be provided. A space as a baggage compartment  11  may be provided inside and the lower part of the seat  40  of the vehicle body  10 . For the frame material forming the vehicle body  10 , for example, stainless steel, aluminum alloy, or the like may be used. 
     The grip  20  may be where a user grips at the time of walking and is attached to the vehicle body  10  via a support part  21 . The grip  20  may be formed like a bar shape extending in the left and right width direction (y direction) intersecting in the advancing direction (x direction) of the manually propelled vehicle  1 . The user can move the manually propelled vehicle  1  forward, backward, braking, and turning by applying human power through gripping the grip  20  with both hands or with one hand. A slip resistant grip  22  may be provided on the grip  20  (left hand grip  22 L and right hand grip  22 R) as illustrated in  FIG. 4 . A height adjustment mechanism may be provided to the grip  20  or the support part  21 . 
     The wheel  30  may be an annular member in order to move the vehicle body part  10  along the ground by rotating in harmony with the walking of the user. The wheel  30  may be rotated by being driven and controlled by the electromotor  80  that receives control commands from the controller  100 . A configuration and drive control of the wheel  30  will be described in detail below. 
     The seat  40  may be a plate-like member for the user to sit down on when seated. The seat  40  may also function as an upper lid of the baggage compartment  11  and is attached so as to enable the upper opening part of the baggage compartment  11  to open and close. 
     The backrest  50  may be a plate-like member for the user to lean back against when seated on the seat  40 . The backrest  50  may be attached to the support part  21  or integrally provided with the vehicle body  10 . 
     The user interface  60  may be a device for exchanging information between the user and the controller  100 . The user interface  60  may be provided at a position where the user can easily operate, for example, on the grip  20  that is near the height of the eyes of the user. 
     The user interface  60  may comprise a manual operation part  61  and a notification part  62 . The manual operation part  61  may receive the manual operation by the user including, for example, an ON/OFF switch button on the electromotor assist function. The notification part  62  informs a variety of information to the user. As the notification part  62 , a light emitting diode, a liquid crystal display panel, or the like may be used other than a speaker as illustrated in  FIG. 4 . 
     The sensor  70  may monitor surrounding conditions, usage condition of the manually propelled vehicle  1  or a walking posture of the user, and a grip sensor  71  may be included in one or more embodiments of the first example. The grip sensor  71  may detect pressure applied on the grip  20 . The grip sensor  71  may include a left hand grip sensor  71  L provided at the left grip  22 L and a right hand grip sensor  71 R provided at the right hand grip  22 R. A detailed description of the grip sensor  71  will be given below. 
     The electromotor  80  may drive each component of the manually propelled vehicle  1  by electric operation according to instructions from the controller  100 . The wheel driver  81  may electromotively drive the wheel  30  according to instructions from the controller  100 . 
     The power supply  90  may supply power to the user interface  60 , sensor  70 , electromotor  80 , and controller  100 . A secondary battery (such as a nickel-hydrogen battery or lithium-ion battery) attaching to the vehicle body  10  in a removable manner may be used for the power supply  90 . 
     The controller  100  may be a logic circuit (such as a microcomputer) that comprehensively controls the user interface  60 , sensor  70 , and electromotor  80 . The controller  100  may set a variety of parameters (rotation direction of the motor, each target value of the rotation speed, the rotation torque or the like) of the wheel driver  81  according to the output of the grip sensor  71  to realize assisting human power according to a walking posture and intent of the user. 
     The controller  100  may include a grip state detector  101  and a wheel drive controller  102 . The grip state detector  101  may detect a grip state on the grip  20  based on information acquired from the grip sensor  71  and determine a target value of the electromotor assist operation. The wheel drive controller  102  may control the rotation speed and rotation direction of the wheel  30  according to the target value of the electromotor assist operation. 
     Next, one or more embodiments of the wheel  30  and the wheel driver  81  will be described with reference to  FIG. 6  and  FIG. 7  in addition to  FIG. 5 .  FIG. 6  is a schematic diagram illustrating the configuration of the wheel  30  and the wheel driver  81 , and  FIG. 7  is a block diagram illustrating the configuration of the wheel driver  81 . 
     The wheel  30  may be a four-wheel structure comprising a drive wheel  31  and an idler wheel  32  as illustrated in  FIG. 6 . The drive wheel  31  may be composed of a left drive wheel  31 L and a right drive wheel  31 R that rotate around an axle by an assisting power or by human power. The idler wheel  32  may be composed of a left idler wheel  32 L and a right idler wheel  32 R used for turning. 
     The wheel driver  81  may comprise a left wheel driver  81 L and a right wheel driver  81 R respectively corresponding to the left drive wheel  31 L and the right drive wheel  31 R. The left wheel driver  81 L and the right wheel driver  81 R may respectively drive and control the rotation speed and the rotation direction of the left drive wheel  31 L and the right drive wheel  31 R independently. 
     The left wheel driver  81 L and the right wheel driver  81 R may respectively include the same configuration elements as illustrated in  FIG. 7 . The left wheel driver  81 L include a motor  811 L, a motor driver  812 L, a current sensor  813 L, and a rotation angle sensor  814 L. The right wheel driver  81 R may include a motor  811 R, a motor driver  812 R, a current sensor  813 R, and a rotation angle sensor  814 R. The description of the identification codes “L” and “R” indicating the left and right will be omitted unless helpful for illustration purposes. 
     Each of the motors  811 L and  811 R may rotate and drive the left drive wheel  31 L and the right drive wheel  31 R independently. The motor drive  812  may be an inverter circuit for generating a drive current for the motor  811  according to the control signal from the controller  100 . The current sensor  813  may detect the drive current supplied to the motor  811 . The rotation angle sensor  814  may detect the rotation angle of the motor  811 . The wheel drive controller  102  may carry out feedback control of the motor driver  812  so as to match the rotation direction and rotation speed of the motor  811  with the target value according to each output of the current sensor  813  and the rotation angle sensor  814 . 
     Next, one or more embodiments of the grip sensor  71  will be described with reference to  FIG. 8  and  FIG. 9  in addition to  FIG. 4  and  FIG. 5 .  FIG. 8  is a perspective view illustrating a configuration of the grip sensor  71 , and  FIG. 9  is a vertical cross-sectional view illustrating a section of the grip sensor  71  of the grip  20 . Note,  FIG. 8  and  FIG. 9  omit illustrations of the support part  21  and the user interface  60 . Further, in the same manner as described above, the descriptions of the identification codes “L” and “R” indicating the left and right may be omitted unless helpful for illustration purposes. 
     The grip sensor  71  may be a band shape in the direction where the grip  20  extends as illustrated in  FIG. 8  and  FIG. 9 , that is, extending along the left and right width direction (y direction) of the manually propelled vehicle  1 . The grip sensor  71  may be disposed by arranging  4  sheets ( 71 A,  71 B,  71 C, and  71 D) of the same shape and the same size at equal intervals along the circumferential direction on the surface of the grip  20 . The grip sensor  71 A may be attached to the front side of the grip  20 , the grip sensor  71 B may be attached to the top side, the grip sensor  71 C may be attached to the rear side (user side), and the grip sensor  71 D may be attached to the bottom side. 
     The grip sensor  71  may be a sheet-like member, for example, where a plurality of pressure sensors is arranged in a matrix. The plurality of pressure sensors may output electric signals in which the signal level (for example, a voltage value) fluctuates according to the amount of pressure applied to each. For example, when the user is holding the grip  20 , distribution of pressure according to the gripping conditions may be detected by the grip sensor  71 . The pressure distribution may be detected by both the left hand grip sensor  71 L and the right hand grip sensor  71 R when operating with both hands. The pressure distribution may be detected by either one of the left hand grip sensor  71 L or the right hand grip sensor  71 R when operating with one hand 
       FIG. 10  is a perspective view illustrating a state when a user U holds the grip  20 , and  FIG. 11  is an exploded view schematically illustrating the pressure distribution of the grip sensor  71  at that time.  FIG. 10  illustrates only one portion of the grip  20 . 
     For example, when the user U pushes on the grip  20  to move the manually propelled vehicle  1  forward, a thenar and a hypothenar (a thick portion near the wrist) of the palm that may grip the grip  20  may contact the grip sensor  71  strongly as illustrated in  FIG. 10 . Accordingly, the pressure distribution P applied on the near side to the user of the grip sensor  71  illustrated in  FIG. 11 , that is, where a relatively large force is applied focusing around the section of the grip sensor  71 C, may be detected. 
     Furthermore, for example, when the user pulls on the grip  20  to move the manually propelled vehicle  1  backward, the balls of four fingers (forefinger, middle finger, ring finger, and little finger) that grip the grip  20  may contact the grip sensor  71  strongly as illustrated in  FIG. 10 . Accordingly, the pressure distribution P applied on the far side to the user of the grip sensor  71  illustrated in  FIG. 11 , that is, where a relatively large force is applied focusing around the section of the grip sensor  71 A may be detected. 
     With such grip sensor  71 , the controller  100  of the manually propelled vehicle  1  may comprise a grip state detector  101  illustrated in  FIG. 5 . The grip state detector  101  may detect a grip state on the grip  20  based on information acquired from the grip sensor  71 , and may comprise a pressure detecting portion  101   a,  an applied pressure determining portion  101   b,  and a grip state determining portion  101   c.  In one or more embodiments of this example, the grip state detector  101  may be provided in the controller  100 ; however, the grip state detector  101  may also be provided separately from the controller  100 . 
     The pressure detecting portion  101   a  may derive a distribution and an area of an applied pressure region detected by the grip sensor  71 . The pressure detecting portion  101   a  may derive the distribution and the area of the applied pressure region straddling to the  4  grip sensors  71 A,  71 B,  71 C, and  71 D. 
     The applied pressure determining portion  101   b  may determine whether or not the distribution and the area of the applied pressure region detected by the pressure detecting portion  101   a  correspond to a predetermined condition set in advance. The predetermined condition of the distribution and the area of the applied pressure region may be a condition that has been set in advance to correspond to the distribution and the area of the applied pressure region detected by the grip sensor  71  when the user performs normal operation on the manually propelled vehicle  1 , and that is stored in a storage unit or the like (not illustrated). 
     If the distribution and the area of the applied pressure region detected by the grip sensor  71  correspond to the predetermined condition, the user may be gripping the grip  20  firmly in order to perform normal operation on the manually propelled vehicle  1 . Accordingly, the grip state determining portion  101   c  may determine that the predetermined grip state set in advance by, for example, the user is detected when the applied pressure determining portion  101   b  determines that the distribution and the area of the applied pressure region correspond to the predetermined condition set in advance. 
     The grip state detector  101  may use the pressure detecting portion  101   a,  the applied pressure determining portion  101   b  and the grip state determining portion  101   c  to detect the grip state on the grip  20 . Then, when the predetermined grip state, which may be set in advance by the user, is detected by the grip state detector  101 , the manually propelled vehicle  1  may drive the wheel  30  (e.g., it may drive at least one wheel of the wheel system) via the wheel driver  81 . 
     On the other hand, when the predetermined grip state is not detected by the grip state detector  101 , the manually propelled vehicle  1  may stop the assist operation. 
       FIG. 12  is a perspective view illustrating a state when a bag is hooked on the grip  20 , and  FIG. 13  is an exploded view schematically illustrating the pressure distribution of the grip sensor  71  at that time.  FIG. 12  illustrates only one portion of the grip  20 . 
     For example, when the user hooks a handle part Sh of a bag S on the grip  20 , the handle part Sh of the bag S illustrated in  FIG. 12  may contact the grip sensor  71  strongly so that the distribution of the applied pressure region is concentrated at the top local part in the width direction (y direction) of the grip  20 . Accordingly, the pressure distribution P may be detected where a relatively large force is applied downward (z direction) to the upper side of the grip sensor  71  illustrated in  FIG. 13 , that is, focusing around the local part in the width direction (y direction) of the grip sensor  71 B. 
     When the distribution of the applied pressure region is concentrated at the top local part in the width direction of the grip  20  and the area of the applied pressure region does not exceed the predetermined value, which may be set in advance, the applied pressure determining portion  101   b  may determine that the distribution and the area of the applied pressure region do not correspond to the predetermined condition. If the distribution and the area of the applied pressure region detected by the grip sensor  71  do not correspond to the predetermined condition, the user may not be gripping the grip  20  firmly; in other words, the handle part Sh of the bag S may be hooked on the grip  20 . Accordingly, because the predetermined grip state was not detected by the grip state detector  101 , the manually propelled vehicle  1  may stop the assist operation. 
     According to one or more embodiments, the grip state detector  101  may simultaneously detect that the user is gripping the grip  20  and that an object such as the bag S is hooked on the grip  20 . In that case, the manually propelled vehicle  1  may activate the assist operation because the user is gripping the grip  20 . 
     A manually propelled vehicle according to one or more embodiments of the present invention may comprise a vehicle body, a wheel for moving the vehicle body, a grip attached to the vehicle body, a grip sensor that detects a pressure applied to the grip by a user of the manually propelled vehicle, a grip state detector that detects a grip state of the grip based on information acquired from the grip sensor, and a wheel driver that drives the wheel when the grip state detector detects a predetermined grip state. 
     In one or more embodiments of this example, the manually propelled vehicle  1  can detect the grip state for the grip  20  based on the pressure applied to the grip  20 . At that time, the grip state detector  101  can detect the predetermined grip state, i.e., the grip state by the user for the grip  20 . 
     Accordingly, the manually propelled vehicle  1  can distinguish that the grip  20  is gripped intentionally by the user for using the manually propelled vehicle  1  as human power assistance. When the user grips the grip  20 , the wheel  30  is driven, the assist operation unintended by the user can be prevented, and therefore, it can improve safety. 
     Further, the manually propelled vehicle  1  may comprise a pressure detecting portion that detects a distribution and an area of an applied pressure region detected by the grip sensor, an applied pressure determining portion that determines whether the distribution and the area of the applied pressure region correspond to a predetermined condition, and a grip state determining portion that detects the predetermined grip state when the applied pressure determining portion determines that the distribution and the area of the applied pressure region correspond to the predetermined condition. 
     In one or more embodiments of this example, the manually propelled vehicle  1  can determine the grip state by the user for the grip  20  based on the distribution and the area of the applied pressure region of the grip  20 . Accordingly, the manually propelled vehicle  1  can distinguish whether the user is gripping the grip  20  to use the manually propelled vehicle  1  as the human power assistance or, for example, whether the user has hooked a bag S on the grip  20 . When the user has hooked the bag S on the grip  20 , the wheel  30  is not driven, the assist operation unintended by the user can be prevented. Therefore, safety can be improved. 
     Furthermore, the manually propelled vehicle  1  may comprise a grip that has a bar shape that extends in a left and right direction and that intersects an advancing direction of the manually propelled vehicle, the grip sensor is a plurality of grip sensors circumferentially disposed on the grip, each of the plurality of grip sensors has a band shape that extends in the left and right direction, and when the distribution of the applied pressure region is concentrated in an upper local part of the grip and the area of the applied pressure region does not exceed a predetermined value, the applied pressure determining portion determines that the distribution and the area of the applied pressure region do not correspond to the predetermined condition. 
     In one or more embodiments of this example, the manually propelled vehicle  1  can distinguish the applied pressure state that concentrates in the upper local part in the width direction of the grip  20 ; in other words, the handle portion Sh of the bag S, for example, is hooked on the grip  20 . Accordingly, it can determine that the user is not gripping the grip  20  and the assist operation unintended by the user can be prevented. 
     SECOND EXAMPLE  
     Next, a manually propelled vehicle according to one or more embodiments will be described in reference to  FIG. 14  and  FIG. 15 .  FIG. 14  is a perspective view illustrating a state where a user attempts to lift the grip of the manually propelled vehicle, and  FIG. 15  is an exploded view schematically illustrating a pressure distribution of the grip sensor when the user attempts to lift the grip of the manually propelled vehicle. In  FIG. 14 , only one portion of the grip is drawn. Further, the fundamental configuration of the second example may be substantially the same as the first example, which is described above. Accordingly, the same reference numerals are used for like elements, and illustration of the drawings and the descriptions thereof are omitted. 
     The manually propelled vehicle  1  according to one or more embodiments of the second example detects a gripped state on the grip  20  where a grip state detector  101  differs from that of the first example. 
     For example, when a user attempts to lift the grip  20 , the balls of four fingers (forefinger, middle finger, ring finger, and little finger) that grip the grip  20  illustrated in  FIG. 14  may contact the grip sensor  71  strongly so that the distribution of the pressure region is concentrated at a lower part of the grip  20 . Accordingly, the pressure distribution P may be detected at the bottom side of the grip sensor  71  as illustrated in  FIG. 15 , that is, where a relatively large force is applied upward (z direction) focusing around the grip sensor  71 D. 
     When the distribution of the applied pressure region is concentrated at a lower part of the grip  20 , the applied pressure determining portion  101   b  may determine that the distribution and the area of the applied pressure region do not correspond to the predetermined condition. If the distribution and the area of the applied pressure region detected by the grip sensor  71  do not correspond to the predetermined condition, the user may not be gripping the grip  20  firmly; in other words, the user is attempting to lift the grip  20  here. Then, because the predetermined grip state, which may be set in advance by the user, was not detected by the grip state detector  101 , the manually propelled vehicle  1  may stop the assist operation. 
     In this manner, the manually propelled vehicle  1  can distinguish the applied pressure concentrated at the lower part of the grip  20 , i.e., the user is attempting to lift up the grip  20 . Accordingly, it can determine that the user is not gripping the grip  20  to use the manually propelled vehicle  1  under normal manual assistance, and an assist operation unintended by the user can be prevented. 
     THIRD EXAMPLE  
     Next, a manually propelled vehicle according to one or more embodiments of a third example of the present invention will be described with reference to  FIG. 16  and  FIG. 17 .  FIG. 16  is a side view of the manually propelled vehicle, and  FIG. 17  is a block diagram of the manually propelled vehicle. The fundamental configuration of the present example may be substantially the same as the first example described above. Therefore, like reference numerals are used for configuration elements common, and the illustration of the drawings and the descriptions thereof are omitted. 
     The manually propelled vehicle  1  according to one or more embodiments of the third example may comprise a user location sensor  72  as illustrated in  FIG. 16  and  FIG. 17 . The user location sensor  72  may be provided, for example, on the back surface of the vehicle body  10  and may detect a user location. The user location sensor  72  detects the user location further rearward to the back surface of the vehicle body  10  as a detecting region. As the user location sensor  72 , for example, a thermal detecting sensor or an obstacle sensor of a distance measurement type using a laser, infrared rays, ultrasonic or the like may be used. 
     A controller  100  may include a processor  103 . The processor  103  may processes information acquired from the user location sensor  72 . The manually propelled vehicle  1  may not drive the wheel  30  even if the grip state detector  101  detected the predetermined grip when the location of the user cannot be detected by the user location sensor  72 . 
     According to this configuration, the manually propelled vehicle  1  may detect the location of the user in addition to detecting the grip state to the grip  20 . As a result, the manually propelled vehicle  1  can distinguish, for example, whether or not only a bag or the like exists hooked to the grip  20 , or the user also exists near the grip  20 . There is a possibility that the predetermined grip state may be detected despite the user does not grip the grip  20  depending on how the bag or the like is hooked to the grip  20 . However, according to one or more embodiments of this example, because this does not drive the wheel  30  when the location of the user cannot be detected by using the user location sensor  72 , the operation unintended by the user can be prevented more accurately. 
     While the disclosure includes a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments may be devised which do not depart from the scope of the present disclosure. Furthermore, those of ordinary skill in the art would appreciate that certain “units,” “parts,” “elements,” or “portions” of one or more embodiments of the present invention may be implemented by a circuit, processor, etc. using known methods. Accordingly, the scope should be limited only by the attached claims. 
     For example, the left hand grip sensor  71 L and the right hand grip sensor  71 R are physically separated according to one or more embodiments; however, the structure of the grip sensor  71  is not limited thereto. The left hand grip sensor  71 L and the right hand grip sensor  71 R may be formed integrally without separating each other, or the left hand grip sensor  71  L and the right hand grip sensor  71 R may be further separated from each other. 
     One or more embodiments of the present invention can be used for safety improvement of a manually propelled vehicle. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
       1  manually propelled vehicle (e.g., ambulatory assist vehicle) 
       10  vehicle body 
       20  grip 
       70  sensor 
       71  grip sensor 
       72  user location sensor 
       80  electromotor 
       81  wheel driver 
       100  controller 
       101  grip state detector 
       101   a  pressure detecting portion 
       101   b  applied pressure determining portion 
       101   c  grip state determining portion