Patent Publication Number: US-2023148472-A1

Title: Control-by-wire system for a walk-behind self-propelled machine, lawnmower including same, and method

Description:
BACKGROUND 
     The disclosed subject matter relates to a self-propelled walk-behind machine. More particularly, the disclosed subject matter relates to methods and apparatus that incorporate a control-by-wire operation of the machine. 
     Walk-behind machines, such as but not limited to lawnmowers, can include a implement driving assembly that drives at least one implement and a propulsion drive assembly that propels the machine along a travel surface. The implement driving assembly and the propulsion drive assembly can be coupled to a power source such as but not limited to an internal combustion engine or an electric motor. 
     The implement drive assembly can include one or more user inputs that control the movement of the implement. For example, the implement drive assembly can include a user input that stops movement of the implement when the operator of the machine releases the user input. 
     The propulsion drive assembly can include one or more user inputs that can permit an operator of the machine to manually vary the speed at which the propulsion drive assembly propels the machine. Some user inputs are configured to either drive the machine at a single predetermined speed or to terminate self-propulsion of the machine. Other user inputs are configured to permit the operator to vary the speed at which the propulsion drive assembly propels the machine between a range of speeds that can be varied continuously or in steps between a maximum speed and zero speed. 
     The user inputs of a walk-behind machine can include mechanical inputs such as but not limited to a rotary knob, a throttle lever and cable, and a pivoting bale lever. 
     SUMMARY 
     Some embodiments are directed to a control system for a walk-behind self-propelled machine including a handle, a power source, a drive assembly, and an implement selectively driven by the power source. The control by-wire system can include a touch sensor located on the handle configured to transmit a contact signal indicative of an operator of the walk-behind self-propelled machine physically contacting the handle at a predetermined location. The system can further include a controller that is in electrical communication with the touch sensor and configured to enable the power source to drive the implement, such as a lawnmower blade, when the controller receives the contact signal. 
     Some embodiments are directed to a walk-behind lawnmower that can include a cutter housing, a blade, a power source, a plurality of wheels, a handle, a drive assembly, and a control by wire system. The blade rotatably can be supported in the cutter housing. The power source can be mounted on the cutter housing and configured to selectively rotate the blade. The plurality of wheels can support the cutter housing. The handle can be connected to the cutter housing and extend away from the cutter housing. The drive assembly can be mounted to the cutter housing, connected to at least one of the wheels, and configured to selectively drive the at least one wheel. The control-by-wire system can be in electrical communication with the drive assembly. The control by wire system can include a user input structure located on the handle and configured to transmit a plurality of different electrical control signals, a touch sensor mounted on the handle and configured to transmit a contact signal indicative of an operator of the walk-behind lawnmower physically contacting a predetermined location on the handle, and a controller in electrical communication with each of the user input structure and the touch sensor. The controller can be configured to cause the power source to rotate the blade when the controller receives the contact signal and based on which of the electrical control signals the controller receives, and transmit a drive control signal to the drive assembly based on which of the electrical control signals the controller receives. 
     Some embodiments are directed to a method for controlling a walk-behind self-propelled machine. The method can include electronically sensing a presence of an operator grasping a handle of the walk-behind self-propelled machine; enabling a power source to drive an implement of the walk-behind self-propelled machine when the presence of the operator is sensed electronically; displaying a ready signal to the operator when the presence of the operator is sensed electronically; moving the implement when the operator inputs an electronic drive command in response to the ready signal; and terminating movement of the implement when electronically sensing the absence of the operator grasping the handle or when the operator inputs an electronic stop command. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed subject matter of the present application will now be described in more detail with reference to exemplary embodiments of the apparatus and method, given by way of example, and with reference to the accompanying drawings, in which: 
         FIG.  1    is a perspective view of a lawnmower made in accordance with principles of the disclosed subject matter. 
         FIG.  2    is perspective schematic view of a power source assembly and a control system for operating a cutting blade and propelling the lawnmower of  FIG.  1   , with exterior portions of the lawnmower shown in phantom. 
         FIG.  3    is a partial perspective view of a handle of the lawnmower of  FIG.  1   . 
         FIG.  4    is a cross-sectional view taken along line  4 - 4  of  FIG.  3   . 
         FIG.  5    is a cross-sectional view taken along line  5 - 5  of  FIG.  3   . 
         FIG.  6    is a plan view of a printed circuit board of the control system for the lawnmower of  FIG.  1   . 
         FIG.  7    is s schematic view of an exemplary user input of the control assembly of the lawnmower of  FIG.  1   . 
         FIG.  8    is a flowchart illustrating exemplary operational steps of the control assembly of the lawnmower of  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     A few inventive aspects of the disclosed embodiments are explained in detail below with reference to the various figures. Exemplary embodiments are described to illustrate the disclosed subject matter, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a number of equivalent variations of the various features provided in the description that follows. 
     A walk-behind machine made in accordance with principles of the disclosed subject matter can include at least one user input configured as a by-wire user input. The by-wire user input can be configured to transmit an electronic request signal to an electronic control unit (also referred to as an ECU, a microprocessor or a controller). In response to the electronic request signal, the controller can be configured to output an electronic command signal to an electric/electronic device that converts electrical energy into mechanical motion. 
     Exemplary embodiments of the walk-behind self-propelled machine can include but are not limited to a lawnmower, a tiller, a lawn edger, an aerator, and a snowblower. The walk-behind machine can include at least one tool or implement that is mechanically driven (directly or indirectly) by a power source such as an internal combustion engine, an electric actuator such an electric motor or a solenoid, or a hybrid system that includes an internal combustion engine and an electric motor. The tool or implement can be, for example, a blade, tines, or an auger. The same power source can propel the walk-behind self-propelled machine. Alternate embodiments can include a first power source for driving the tool or implement and a second power source for propelling the walk-behind machine. The second power source can be the same type of power source as the first power source or a different type of power source as the first power source. 
     Some embodiments of the walk-behind machine can include at least one electric motor or actuator powered by a source of electric power such as a battery mounted on the walk-behind device or an external source of electricity connected to the machine by an electric cable. One or more by-wire user inputs can provide advantageous control of the electric motor(s) as compared to a mechanical control system. Further details of the by-wire user inputs will be described below. 
       FIG.  1    illustrates an exemplary embodiment of a walk-behind self-propelled machine that is configured as a lawnmower  10 . The lawnmower  10  can include a cutter housing  12 , a pair of front wheels  14 , a pair of rear wheels  16 , a handle  18  and a power source assembly  20 . The rear wheel  16  on the right side of the lawnmower is obstructed from view in Fig,  1  by the cutter housing  12 .  FIG.  2    shows the right rear wheel  16  in phantom. 
     Referring to  FIG.  2   , the lawnmower  10  can include a blade  22  and a blade shaft  24  connected to each of the blade  22  and the power source assembly  20 . The power source assembly  20  can be configured to selectively rotate the blade shaft  24  and the blade  22  in the cutter housing  12  about a blade axis A. The blade shaft  24  can be referred to as a component of the power source assembly  20 . Alternatively, the blade shaft  24  can be referred to as a component that is connected to and driven by the power source assembly  20 . 
     The cutter housing  12  can be referred to as a mower deck or as a cutter deck or as a deck. Referring to Fig,  1 , the cutter housing  12  can include an opening at a rear end  26  of the cutter housing  12 . The lawnmower  10  can include a collection bag that can be selectively attached to and detached from the rear end  26 . The opening and the collection bag are omitted for simplicity and clarity of the drawing figures. The collection bag can be in communication with the opening such that vegetation clippings produced by the blade  22  can be collected in the collection bag. 
       FIG.  2    schematically illustrates exemplary components of the power source assembly  20 . The power source assembly  20  can include a housing  28  (shown in phantom), a battery pack  30 , a blade motor  32 , a blade motor driver  34 , a drive assembly  36  and a control-by-wire system  38  (also referred to as a control system). Referring to  FIGS.  1  and  2   , the housing  28  can contain the battery pack  30 , the blade motor  32  and the blade motor driver  34 . The drive assembly  36  can be spaced away from the housing  28 . 
     The battery pack  30  can include at least one battery cell and a case that houses the at least one battery cell. The battery cell can be configured to store electricity and supply electricity to the blade motor  32 . 
     The blade motor  32  can be a direct current electric motor or an alternating current electric motor. Embodiments can include a blade motor  32  that is configured as a direct current outer rotor motor that includes an inner stator and an outer rotor. The blade motor  32  can include one or more sensors that provide the blade motor driver  34  with information regarding the temperature, rotational speed, power output, etc., of the blade motor  32 . The outer rotor of the blade motor  32  can be directly connected to the shaft  24  in any appropriate manner such that the blade motor  32  can cause the blade shaft  24  to rotate. 
     The blade motor driver  34  can be in electrical communication with each of the battery  30  and the blade motor  32 . The blade motor driver  34  can be configured to convert power from the battery pack  30  into output power supplied to the blade motor  32 . The blade motor driver  34  can be configured to monitor the operational conditions of the blade motor  32  and the battery pack  30 . The blade motor driver  34  can be configured to control the voltage and/or current output by the battery pack  30  based on the operational conditions of the blade motor  32  and the battery pack  30  switching one or more power transistors to adjust the supply of electrical power to the blade motor  32 . 
     The blade motor driver  34  can also be configured to control the voltage or current output by the battery pack  30 , and to supply the voltage or current to the blade motor  32  using the one or more power transistors based on one or more inputs to the control assembly  38  by the operator of the electric lawnmower  10 . 
     The blade motor driver  34  can be in electrical communication with each of the control system  38 , the blade motor  32  and the battery pack  30 . The blade motor driver  34  can be configured to initiate, adjust or terminate supply of voltage or current from the battery pack  30  to the blade motor  32  based on inputs received from the control system  38 , the battery pack  30  and the blade motor  32 . The blade motor driver  34  can also be configured to regulate the charging of the battery cell(s) of the battery pack  30 . 
     The drive assembly  36  can be mounted to the cutter housing  12  at a position that is underneath the cutter housing  12 . The drive assembly  36  can include a drive transmission  40  and a propulsion motor driver  42 . The propulsion motor driver  42  can be in electrical communication with each of the battery pack  30  and the drive transmission  40 . A drive shaft  44  can be connected to each of the drive transmission  40  and at least one of the rear wheels  16  (and/or front wheel(s)  14 ) in any appropriate manner such that the drive transmission  40  can cause the drive shaft  44  to rotate, which in turn can cause the rear wheels  16  (and/or front wheel(s)  14 ) to rotate. 
     The drive transmission  40  can also include a propulsion motor  46  and a gear transmission  48  connecting the propulsion motor  46  to the drive shaft  44 . The propulsion motor  46  can be a direct current electric motor or an alternating current electric motor. The propulsion motor  46  can include one or more sensors that provide the propulsion motor driver  42  with information regarding the temperature, rotational speed, power output, etc., of the propulsion motor  46 . 
     The propulsion motor driver  42  can be in electrical communication with each of the battery pack  30 , the control system  38  and the propulsion motor  46 . The propulsion motor driver  42  can be configured to convert power from the battery pack  30  into output power supplied to the propulsion motor  46 . The propulsion motor driver  42  can be configured to monitor the operational conditions of the propulsion motor  46  and the battery pack  30 . The propulsion motor driver  42  can be configured to control the voltage or current output by the battery pack  30  based on the operational conditions of the propulsion motor  46  and the battery pack  30  by switching one or more power transistors to adjust the supply of electrical power to the propulsion motor  46 . 
     The propulsion motor driver  42  can also be configured to control the voltage or current output by the battery pack  30 , and to supply the voltage or current to the propulsion motor  46  based on one or more inputs by the operator of the electric lawnmower  10  using the one or more power transistors. 
     The propulsion motor driver  42  can be configured to initiate, adjust or terminate supply of voltage or current from the battery pack  30  to the propulsion motor  46  based on inputs received from the battery pack  30 , the propulsion motor  46  and one or more user inputs to the control system  38 . 
     The control system  38  can include a plurality of user inputs (sensors/switches)  54 ,  56 ,  64 ,  66 ,  68 ,  70 ,  72 , a main controller  60  and a sensor array  62 . The control system  38  can be mounted on the handle  18  in any appropriate position and orientation on the handle  18  that can facilitate actuation of the user inputs by an operator of the lawnmower  10 . The control system  38  can be configured to actuate one or more operational features of the lawnmower  10 . 
     The main controller  60  can be in electrical communication with the battery pack  30 , the propulsion motor driver  42 , each of user inputs  54 ,  56 ,  64 ,  66 ,  68 ,  70 ,  72  and the sensor array  62 . The main controller  60  can be configured to signal the blade motor driver  34  to initiate, adjust or terminate supply of voltage or current from the battery pack  30  to the blade motor  32  based on inputs received from any of the battery pack  30 , the blade motor  32  and the user inputs  54 ,  56 ,  64 . The main controller  60  can be configured to signal the propulsion motor driver  42  to initiate, adjust or terminate supply of voltage or current from the battery pack  30  to the propulsion motor  46  based on inputs received from any of the battery pack  30 , the propulsion motor  46 , the inputs  54 ,  56 ,  66 ,  68 ,  70 ,  72  and the sensor array  62 . The main controller  60  can be mounted at any appropriate location on the lawnmower  10  such as but not limited to an upper end of the handle  18  that can be manipulated by the operator to steer the lawnmower  10 . 
     Referring to  FIG.  1   , the sensor array  62  can be configured to measure rotational motion of the lawnmower  10  about each of the X-axis, the Y-axis and the Z-axis. The X, Y, and Z-axes are displaced away from the lawnmower  10  for clarity of the drawing. However, the origin O is intended to be located on the driveshaft  44  and equidistant from each of the rear wheels  16 . The sensor array  62  can include any appropriate type and number of sensor(s) that is/are configured to measure movement about each of the X-, Y- and Z-axes. For example, the sensor array  62  can include a three-axis gyroscope that is mounted on the printed circuit board  58 . Alternate embodiments can include a sensor array  62  that includes at least two sensors, where each of the sensors is configured to measure rational motion of the lawnmower  10  about a respective one of the X-axis and the Z-axis. 
     Referring to  FIG.  3   , the handle  18  can include a handle base  74 , a first control handle  76 , a second control handle  78  and an upper cross member  80  all connected to each other to form a symmetrical polygonal shape. The control handles  76 ,  78  can be spaced apart from each other and inclined toward each other. The handle base  74  can extend from and be connected to each of the control handles  76 ,  78 . The upper cross member  80  can be connected to and extend from each of the control handles  76 ,  78 . The upper cross member  80  can be spaced away from and substantially parallel to the handle base  74 . 
     Referring to  FIGS.  3  and  4   , the handle  18  can include a main body  82  and a lower half  84  that are formed as separate structures to facilitate the installation of the user inputs  54 ,  56 ,  64 ,  66 ,  68 ,  70 ,  72 , the main controller  60  and the sensor array  62  on the handle  18 . The lower half  84  can form a lower half of each of the first control handle  74 , the second control handle  76  and an upper cross member  80 . The main body  82  can form an upper half of each of the first control handle  76 , the second control handle  78  and the upper cross member  80 . 
     Referring to  FIGS.  1 - 3   , the user inputs of the control system  38  can include a left-side touch sensor  54 , a right-side touch sensor  56 , a start switch  64 , a left-side clutch switch  66 , a right-side clutch switch  68 , a speed decrease button  70 , and a speed increase button  72 . The capacitance touch sensors  54 ,  56  can be located inside of the  76 ,  78  and are obstructed from view in  FIG.  1   . The capacitance touch sensors  54 ,  56  are schematically illustrated in  FIG.  2    and schematically illustrated as dashed lines in  FIG.  3   . 
     The touch sensors  54 ,  56  can be in electrical communication with the main controller  60 . The touch sensors  54 ,  56  can be configured to transmit an electrical contact signal to the controller main  60  when the operator&#39;s hand contacts the handle  18  in the area where the sensors  54 ,  56  are located. The touch sensors  54 ,  56  can be any appropriate sensor such as but not limited to a capacitance sensing element, a resistance switch, and a piezoelectric switch. For example, each of the touch sensors  54 ,  56  can be configured as capacitance sensing element that includes a metal foil, or a metal plate, or a rigid printed circuit board, or a flexible printed circuit board. 
     Referring to  FIGS.  3  and  4   , the left-side touch sensor  66  and the right-side touch sensor  68  can be mounted on the lower half  84  at locations that extend along the first control handle  74  and the second control handle  76 , respectively. The lower half  84  can include an outer surface that is also a contact surface of the touch sensors  66 ,  68  that is engageable by the operator of the lawnmower  10 . Alternative embodiments can include a pair of openings through the lower half  84  and a surface of the touch sensors  54 ,  56  can fill a respective one of the openings. 
     Referring to  FIGS.  1 - 3  and  5   , the start switch  64  can be in electrical communication with the main controller  60 . The start switch  64  can be configured to transmit an electrical command signal to the main controller  60  when the operator hand activates the start switch  64 . The start switch  64  can be any appropriate switch that can transmit an electrical command signal to the controller  60  that is indicative of a request by the operator to start rotation of the blade  22  when the blade  22  is stopped or indicative of a request by the operator to stop rotation of the blade  22  when the blade  22  is rotating. 
     The main controller  60  can be configured to signal the blade motor driver  34  to cause the blade motor  32  to rotate the blade  22  when the main controller receives the electrical command signal from the start switch  64  and the blade  22  is stopped (i.e., the blade motor  32  is in an off state). The main controller  60  can be configured to signal the blade motor driver  34  to cause the blade motor  32  to stop rotation of the blade  22  when the main controller  60  receives the electrical command signal from the start switch  64  and the blade  22  is rotating (i.e., the blade motor  32  is in an on state). 
     Referring to  FIGS.  5 - 7    collectively, the start switch  64  can include a circuit board  58 , at least one light source  86 , at least one switch contact  88 , a start button  90 , at least one pill contact  92  and a resilient web  94 . 
     The main controller  60  and the sensor array  62  can be mounted on the circuit board  58 . 
     Each of the light sources  86  can be mounted on the printed circuit board  58  and in electrical communication with the controller  60 . The light source(s)  86  can be any appropriate light source such as but not limited to a light emitting diode or a laser diode and can emit any appropriate color of light. When including a plurality of light sources, the light sources  86  can be spaced apart from each other along the circuit board to provide a more uniform illumination of the start button  90  along the extent of the start button  90 . 
     The switch contact  88  can be mounted on the printed circuit board  58  and in electrical communication with the controller  60 . The switch contact  88  can have any appropriate shape or structure such as but not limited to a plurality of interleaved finger contacts. When including a plurality of switch contacts, the switch contacts  88  can be spaced part from each other along the printed circuit board  58 . 
     The start button  90  can be formed from a transparent or translucent material such that at least some of the light emitted by the light source(s)  86  passes through the start button  90 . Referring to  FIGS.  5  and  7   , the start button  90  can include an engagement surface  96  and an opposing surface  98 . The engagement surface  96  can face the operator and be exposed outside of the handle  18 . The opposing surface  98  can face the printed circuit board. Referring to  FIG.  5   , the handle base  74  can include a first opening  100 . The start button  90  can extend into and out of the handle base  74  through the first opening  100 . 
     Referring to  FIGS.  7   , the pill contact  92  can be mounted on the opposing surface  98  of the start button. The number of pill contacts  92  can correspond to the number of switch contacts  88  and spaced along the opposing surface  98  such each pill contact  92  is paired with a respective one of the switch contacts  88 . The pill contacts  92  and the switch contacts  88  are spaced away from the location of the cross-sectional view of  FIG.  5   . 
     The resilient web  94  can extend from and be connected to each of the printed circuit board  58  and the start button  90 . The web  94  can bias the start button  90  away from the printed circuit board  58  such that the pill contact  92  is spaced away from the switch contact  88  when the start switch is not activated by the operator of the lawnmower  10 . 
     Referring to  FIG.  1 - 3   , each of the clutch switches  66 ,  68  can be in electrical communication with the main controller  60 . The clutch switches  66 ,  68  can be configured to cause the drive assembly  36  to selectively drive the rear wheels  16 . The left-side clutch switch  66  can be configured to transmit a drive signal to the main controller  60  when the operator engages the left-side clutch switch  66  and terminate transmission of the drive signal when the operator disengages from the left side clutch switch  66 . The right-side clutch switch  68  can be configured to transmit a drive signal to the main controller  60  when the operator engages the right-side clutch switch  68  and terminate transmission of the drive signal when the operator disengages from the right-side clutch switch  68 . 
     The main controller  60  can be configured to place the drive assembly  36  in an on state, in which the drive assembly  36  drives the rear wheels  16 , when the main controller receives the drive command from either one or both of the clutch switches  66 ,  68 . The main controller  60  can be configured to place the drive assembly  36  in an on state by signaling the propulsion motor driver  42  to supply electricity from the battery pack  30  to the propulsion motor  46 . The propulsion motor driver  42  can be configured to signal the propulsion motor  46  to rotate the rear wheels  16  such that the lawnmower  10  moves at a speed that corresponds to the speed that the operator has set using the speed decrease switch  70  or the speed increase switch  72 , or in accordance with a predetermined default speed. The main controller  60  can be configured to signal the propulsion motor driver  42  to terminate the drive to the rear wheels  16  when both of the clutch switches  66 ,  68  terminate transmission of the electrical drive signal. Thus, the operator can cause the lawnmower  10  to propel itself by engaging at least one of the clutch switches  66 ,  68 . 
     Referring to  FIG.  4   , each of the clutch switches  66 ,  68  can include a printed circuit board  102  at least one switch contact  104 , a clutch button  106 , at least one pill contact  108  and a resilient web  110 .  FIG.  4    shows the components of the left-side clutch switch  66  with the understanding that the right-side clutch switch  68  can have the same components and layout as the left-side clutch switch  66 . The contacts  104 ,  108 , button  106  and web  110  can be arranged in accordance with the corresponding components of the start switch  64  described above. The pill contact  108  and the switch contact  104  are schematically illustrated in from Fig,  4  for reasons of clarity and simplicity of the drawing. 
     The speed decrease button  70  and the speed increase button  72  can be configured to permit the operator of the lawnmower  10  to set a maximum speed value from a range of possible maximum speed values at which the drive assembly  36  will propel the lawnmower  10 . The operator can selectively decrease or increase the maximum speed by pressing the speed decrease button  70  or the speed increase button  72 , respectively, until the drive assembly  36  propels the lawnmower  10  at the desired speed. The speed decrease button  70  and the speed increase button  72  can be configured to allow the operator of the lawnmower  10  to continuously vary the speed at which the drive assembly  36  propels the lawnmower  10 . 
     Each of the speed switches  70 ,  72  can have components, layout and operation as described above with respect to the start switch  64  and the clutch switches  66 ,  68 . Each of the speed switches can be in electrical communication with the main controller  60  and can be configured to transmit an electrical speed decrease signal and an electrical speed increase signal, respectively, when engaged by the operator. 
       FIG.  8    illustrates exemplary control cycles for operating the lawnmower  10  using the control-by-wire system  38 . At step S 100 , the operator of the lawnmower  10  can grasp the handle  18  at a location that includes either of the touch sensors  54 ,  56 . The activated one(s) of the touch sensors  54 ,  56  can transmit the electrical contact signal to the main controller  60 . 
     In response to the electrical contact signal, the main controller  60  can signal the light source(s)  86  of the start switch  64  to illuminate the start button  90 . This illumination can be a constant illumination or a flashing illumination as indicated at step S 102 . 
     When the operator displaces the illuminated start button  90  so that the pill contact  92  engages the switch contacts  88 , the start switch  64  can transmit the electrical command signal to the main controller  60  as indicated at step S 104 . Upon receiving the electrical command signal, the main controller  60  can cause the blade motor  32  to turn on and rotate the blade  22  as indicated at step S 106 . 
     When the blade motor  32  is on, the operator can either press the start button  64  as indicated by arrow path AP 1  or release the handle  18  such that the operator no longer grasps the handle  18  at both locations that correspond to the touch sensors  54 ,  56  as indicated by arrow path AP 2 . Either of these actions by the operator can signal the main controller  60  to cause the blade motor  32  to stop rotation of the blade  22  as indicated at step S 108 . 
     When the operator presses the start button  90  during operation of the blade motor  32  (arrow path AP 1 ), the operator can signal the main controller  60  to resume operation of the blade motor  32  by engaging the start button  90 , as indicated at step S 102 . When the operator releases the handle  18  such that the touch sensors  54 ,  56  terminate the transmission of the electrical contact signal during operation of the blade motor  32  (arrow path AP 2 ), the operator must grasp the handle  18  at a location that contains at least one of the touch sensors  54 ,  56  before the main controller  60  can resume operation of the blade motor  32 . 
     Accordingly, the control-by-wire system  38  can provide the operator with a simple and convenient control of the lawnmower  10  by merely grasping the handle  18  and engaging simple on/off switches such as the switches  64 ,  66 ,  68 ,  70 ,  72 . Further, the control-by-wire system  38  can automatically control the ground speed of the lawnmower  10  when the operator changes direction of the lawnmower  10  to begin cutting a new row of vegetation. 
     For example, the main controller  60  can be configured to operate in a first mode and in a second mode. In the first mode, the main controller  60  can be configured to cause the drive transmission  40  to propel the lawnmower  10  at a first speed which is set by the operator via the speed switches  70 ,  72 . The first speed can be referred to as a user requested speed. In the second mode, the main controller  60  can be configured to cause the drive transmission  40  to propel the lawnmower  10  at a second speed that is less than the first speed. The second speed can be a predetermined speed. Exemplary embodiments can include a main controller  60  that operates in a second mode such that the main controller  60  causes the drive transmission  40  to stop propulsion of the lawnmower  10  by placing the drive transmission  40  in an off state such that the drive transmission  40  does not cause the drive shaft  44  to rotate the rear wheels  16  of the lawnmower  10 . 
     The main controller  60  can select the first mode and the second made based on data from the sensor array  62 . The data from the sensor array  62  can be indicative of a first angular velocity ω 1  and a second angular velocity ω 2  of the lawnmower  10 . The first angular velocity ω 1  can be measured about a first rotational axis that is parallel to the Z-axis illustrated in  FIG.  1   . The first angular velocity ω 1  and the first rotational axis can also be referred to as a yaw rate and a yaw axis, respectively. The second angular velocity ω 2  can be measured about a second rotational axis that is parallel to the X-axis illustrated in  FIG.  1   . The second angular velocity ω 2  and the second rotational axis can also be referred to as a pitch rate and a pitch axis, respectively. 
     Specifically, the main controller  60  can compare the first angular velocity ω 1  to a first threshold ω T1  and the second angular velocity ω 2  to second threshold ω T2 . If the first angular velocity ω 1  is greater than the first threshold ω T1  and the second angular velocity ω 2  is greater than the second threshold ω T2 , then the main controller  60  can select the second mode. However, if either the first angular velocity ω 1  is less than or equal to the first threshold ω T1  or the second angular velocity ω 2  is less than or equal to the second threshold ω T2 , the main controller  60  can continue the process of determining whether to select the first mode, remain in the second mode, or terminate the second mode and select the first mode. 
     The first and second thresholds ω T1 , ω T2 , can be set at respective predetermined angular velocity values that best or most likely correspond to the rotational motion of the lawnmower  10  as the operator tilts and pivots the lawnmower  10  at the end of a completed row of vegetation and begins a new row of vegetation to be cut. The first and second thresholds ω T1 , ω T2 , can be set at a respective angular velocity value that can maintain the main controller  60  in the first mode or reduce a frequency at which the main controller  60  selects the second mode when the operator is turning the lawnmower  10  while traversing an inclined surface but not transitioning from a completed row of cut vegetation to a new row of vegetation to be cut. 
     Thus, main controller  60  can be configured to automatically select and switch between the first mode and the second mode using two angular velocity values of the walk-behind self-propelled machine that are measured about two different rotational axes. This automatic turn-detection feature of the main controller  60  can permit the operator of the lawnmower to tilt and pivot the lawnmower toward a new row of vegetation to be cut without removing either hand from the handle  18  or moving either hand to manipulate the speed switches  70 ,  72 . The drive transmission  40  can be disconnected during the turn at each end of a row to allow for easy manipulation and turning of the lawnmower  10 . Alternatively, the speed of the motor  32  can be adjusted downward for a period of time when the sensor array  62  indicates that the lawnmower  10  is experiencing a turn at the end of a row. 
     Each of the drivers  34 ,  42  and the main controller  60  can be referred to as an electronic control unit (“ECU”) or as a central processing unit (“CPU”) or as a microcontroller. The drivers  34 ,  42  and the main controller  60  can be configured with hardware, with or without software, to perform the assigned task(s). The drivers  34 ,  42  and the main controller  60  can include or be electrically connected to any appropriate memory device that can store and retrieve programs and/or data for use by the drivers  34 ,  42  and the main  60 . Although the propulsion motor driver  42  and the main controller  60  are referred to separately, a single controller (instead of separate propulsion motor driver  42  and controller  60 ) can be used to perform the same or similar functions as the driver  42  and the main controller  60  and other control mechanisms including the blade motor driver  34 . 
     Electrical communication lines (not numbered) can connect each of the drivers  34 ,  42  and the main controller  60  to one or more components of the power supply assembly  20  in any appropriate manner. Electrical communication can be either one-way communication or two-way communication and can be networked or not networked, and can be wireless if desired. The sensor array  62  can be configured with hardware, with or without software, to perform the assigned task(s). The sensor array  62  include one or more smart sensors such that the sensor array  62  can process the raw data collected by the sensor array  62  prior to transmission to the main controller  60  or the sensor array  62  can be configured as a simple sensor that passes the raw data directly to the main controller  60  without any manipulation of the raw data. The sensor array  62  can be configured to send data to the main controller  60 , with or without a prompt from the main controller  60 . 
     The disclosed subject matter allows the operator to keep their hands on the handlebar at all times. Instead of modulating a lever or speed adjustment knob, the operator can rely on the turn-sensing drive shutoff system to turn off the transmission when they turn. If they need to adjust the speed during use, they can use their thumbs to make the adjustment, without repositioning their hand or grip. The addition of capacitance sensing makes the control simpler, more comfortable, and more intuitive to use. 
     While certain embodiments of the invention are described above, it should be understood that the invention can be embodied and configured in many different ways without departing from the spirit and scope of the invention. 
     For example, embodiments are disclosed above in the context of the button-pill contact switches  64 ,  66 ,  68 ,  70 ,  72 . However, alternate embodiments can include any type of electrical signaling device such as but not limited to a rotary dial, a toggle switch, a tactile switch, a piezoelectric switch, a touch sensor such as touch sensors  54 ,  56 , a touch screen displaying graphical information representative of the operational status of the lawnmower  10  and/or at least one control option, etc. 
     Each of the signals transmitted to or by the main controller  60  can be a digital signal or an analog signal. Alternative embodiments can include one or more analog signals and one or more digital signals transmitted to or by the controller  60 . 
     Instead of a single driveshaft  44  as shown in  FIG.  2   , each of the rear wheels  16  can be connected to the drive transmission  40  by a respective driveshaft. Alternate embodiments can include the driveshaft connected to only one of the rear wheels  16 , or to only one or both of the front wheels  14 .