Electric vehicles

Abstract

An electric wheelchair 1 comprises: a vehicle body 2a; a drive mechanism 4 that drives the vehicle body 2a; a control device 18 that controls the drive mechanism 4 by providing a speed command value to the drive mechanism 4; and a first operation unit 10 having a first grip 20 that is movable in the front-rear direction of the vehicle body 2a and a first detection unit that detects the amount of displacement of the first grip 20 in the front-rear direction with respect to the vehicle body 2a. The control device 18 is equipped with a processing unit 38 that executes generation processing for generating a speed command value using a model that includes an elastic term based on the displacement amount and a viscosity term based on the derivative value of the displacement amount.

Description

[Technical Field]

[0001] The present invention relates to an electric vehicle. [Background technology]

[0002] Patent Document 1 discloses an electric wheelchair. This electric wheelchair includes an operating force detector, a motor for driving the vehicle, and a control circuit. The operating force detector includes a handle protruding from the rear of the vehicle and a potentiometer. When the operator moves the handle forward or backward from the neutral position, the output of the potentiometer changes in accordance with the displacement, and the output of the potentiometer is sent to a control circuit. The control circuit obtains the displacement of the handle based on the output of the potentiometer. The control circuit controls the motor to move the vehicle forward when the handle is displaced forward by the operator, and controls the motor to move the vehicle backward when the handle is displaced backward. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-336803 Summary of the Invention [Problem to be solved by the invention]

[0004] The control circuit controls the motor based on the displacement of the handle, and therefore controls the vehicle speed regardless of the walking speed of the operator. Therefore, the walking speed of the operator and the vehicle speed do not necessarily match, and if there is a difference between the walking speed of the operator and the traveling speed of the electric wheelchair, the distance between the operator and the vehicle may become closer or farther. In such cases, the operator must adjust the amount of operation of the handlebars to walk in accordance with the vehicle speed, which poses a problem of poor operability. The above-mentioned problem is not limited to electric wheelchairs, but occurs in any electric vehicle that detects the operating force of the operator and travels together with the operator. [Means for solving the problem]

[0005] An electric vehicle that is an embodiment of the present disclosure comprises a vehicle body, a drive mechanism for driving the vehicle body, a control device that controls the drive mechanism by giving a command value to the drive mechanism, a first grip that can move in the fore-and-aft direction of the vehicle body, and a first operating unit that has a first detection unit that detects a first displacement amount of the first grip in the fore-and-aft direction relative to the vehicle body, and the control device comprises a processing unit that executes a generation process that generates the command value using a model that includes an elastic term based on the first displacement amount and a viscous term based on a derivative value of the first displacement amount. [Effects of the Invention]

[0006] According to the present disclosure, good operability can be achieved in an electric vehicle. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of an electric wheelchair according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the first operating unit. [Figure 3] FIG. 3 is a block diagram showing an example of a configuration for controlling the operation of a motor in an electric wheelchair. [Figure 4] FIG. 4 is a diagram showing a manner in which an operator operates an electric wheelchair. [Figure 5] FIG. 5 is a block diagram showing an example of the processing contents executed by the processing unit of the control device. [Figure 6] FIG. 6 is a plan view of the electric wheelchair. DETAILED DESCRIPTION OF THE INVENTION

[0008] First, the contents of the embodiment will be listed and explained. [Outline of the embodiment] (1) An electric vehicle that is an embodiment of the present disclosure includes a vehicle body, a drive mechanism for driving the vehicle body, a control device that controls the drive mechanism by providing a command value to the drive mechanism, a first grip that can move in the fore-and-aft direction of the vehicle body, and a first operating unit that has a first detection unit that detects a first displacement amount of the first grip in the fore-and-aft direction relative to the vehicle body, and the control device includes a processing unit that executes a generation process that generates the command value using a model that includes an elastic term based on the first displacement amount and a viscous term based on a derivative value of the first displacement amount.

[0009] According to the above configuration, the drive mechanism is controlled using a model including an elastic term based on the first displacement amount and a viscosity term based on a derivative of the first displacement amount, so that the drive mechanism can be controlled so that the movement of the vehicle body relative to the first displacement amount simulates mechanical impedance characteristics. As a result, when the speed of the vehicle body is controlled so that the distance between the operator and the vehicle body is constant, it is possible to prevent the operator from walking in accordance with the speed of the vehicle body, thereby achieving good operability.

[0010] (2) In the above-described electric vehicle, it is preferable that the generation process includes a thrust calculation process that uses the model to determine a target thrust, which is a target value of thrust in the longitudinal direction, and a command value generation process that generates the command value based on the target thrust. In this case, the control device can generate a command value based on the target thrust.

[0011] (3) Furthermore, if the electric vehicle further includes an acquisition unit that acquires speed information indicating the traveling speed of the vehicle body, it is preferable that in the propulsion force calculation process, the target propulsion force is calculated based on the calculation result of the model and the longitudinal deceleration force obtained based on the speed information. In this case, the target thrust can be calculated by taking into account deceleration based on frictional forces and other factors that occur in response to the vehicle's speed, and by limiting the vehicle's running speed, thereby enabling more precise speed control and achieving better operability.

[0012] (4) It is preferable that the drive mechanism includes a pair of left and right drive wheels, a pair of motors that drive the pair of drive wheels, and a pair of drive circuits that drive the pair of motors based on the command value. In this case, the control device can control the speed of the vehicle body by individually controlling the pair of motors.

[0013] (5) When an operator attempts to turn the vehicle body in a predetermined direction via the first operating unit while the electric vehicle is under speed control, the pair of drive circuits attempt to maintain the operating state based on the command value, and control the pair of motors to generate torque to turn the vehicle in the direction opposite to the predetermined direction. Therefore, the current value flowing through the pair of motors indicates the external force acting on the vehicle body via the first operating unit. Therefore, if the electric vehicle further includes a pair of current detection units that detect the currents flowing through the pair of motors, it is preferable that the processing unit executes an external force calculation process to determine the external force acting on the vehicle body based on a pair of current values ​​detected by the pair of current detection units, and that in the generation process, the command value is generated based on the calculation result using the model and the external force. This makes it possible to control the speed of the vehicle body based on the first displacement amount of the first operating unit and the external force acting on the vehicle body via the first operating unit.

[0014] (6) In a case where the electric vehicle further includes a pair of rotation detectors that detect the rotational speeds of the pair of motors, the generation process may include a thrust calculation process that uses the model to determine a target thrust, which is a target value of the thrust in the longitudinal direction; a turning force calculation process that determines a target turning force, which is a target value of the turning force in the turning direction of the vehicle body, based on the external force and the output of the pair of rotation detectors; and a command value generation process that generates a pair of command values ​​for each of the pair of motors based on the target thrust and the target turning force. In this case, the target force for moving the vehicle body can be controlled separately as a forward / rearward propulsion force and a turning force in the turning direction, thereby enabling the speed of each of the pair of motors to be controlled appropriately.

[0015] (7) When the external forces include an external force in the longitudinal direction and an external force in the turning direction, and the propulsion force calculation process calculates the target propulsion force based on the calculation results of the model and the external force in the longitudinal direction, the turning force calculation process may be configured to calculate the target turning force based on the external force in the turning direction and the outputs of the pair of rotation detectors. In this case, by dividing the external force into an external force in the longitudinal direction and an external force in the turning direction, the target propulsive force and the target turning force can be calculated with higher accuracy.

[0016] (8) When the electric vehicle further includes a second operating unit having a second grip movable in the fore-and-aft direction and a second detection unit that detects a second displacement amount of the second grip relative to the vehicle body in the fore-and-aft direction, the first operating unit is provided on the left side of the vehicle body and the second operating unit is provided on the right side of the vehicle body, and the generation process includes a turning speed calculation process that calculates a target turning speed, which is a target value of the turning speed in the turning direction, based on the external force and the difference between the first displacement amount and the second displacement amount, the turning force calculation process calculates the target turning force based on the target turning speed and the output of the pair of rotation detectors. In this case, for example, an upper limit and a lower limit may be set for the value obtained from the difference, and when the difference is extremely large or extremely small, an upper limit or a lower limit may be set for the value obtained from the difference, thereby providing a dead band for the difference. This places a limit on the movement in the turning direction based on the difference, making it possible to prevent the operator from making an unintended movement.

[0017] (9) Furthermore, when the electric vehicle further includes a wheelchair section, it is preferable that the vehicle body is the vehicle body of the wheelchair section.

[0018] [Details of the embodiment] Preferred embodiments will now be described with reference to the drawings. [Overall structure] 1 is a perspective view of an electric wheelchair according to an embodiment. This electric wheelchair 1 has a function of assisting the operator by driving the drive wheels of the electric wheelchair 1 when pushed from behind by the operator.

[0019] The electric wheelchair 1 includes a wheelchair section 2, a drive mechanism 4, a control box 6, a first operating section 10, and a second operating section 12. The wheelchair section 2 is a typical wheelchair and includes a vehicle body 2a mainly composed of a frame made of metal pipes or the like, a pair of main wheels 2b provided on the left and right sides of the vehicle body 2a, and a pair of casters 2c also provided on the vehicle body 2a. The vehicle body 2a has a seat 2a1 on which the passenger sits and a backrest 2a2. The electric wheelchair 1 is configured by mounting a drive mechanism 4, a control box 6, a first operating unit 10, and a second operating unit 12 on a wheelchair unit 2 that can be used as a wheelchair.

[0020] In the following description, the direction in which the rider faces when riding in the electric wheelchair 1 (the direction in which the backrest 2a2 faces forward) is referred to as the forward direction, and the opposite direction is referred to as the rearward direction. Therefore, the rider rides facing the front of the electric wheelchair 1. Also, the direction facing left as seen from the rider is referred to as the leftward direction, and the direction facing right as seen from the rider is referred to as the rightward direction.

[0021] The drive mechanism 4 includes a pair of drive units 14. The pair of drive units 14 are fixed to the left and right sides of the vehicle body 2a. The pair of drive units 14 are arranged on the vehicle inward side of the pair of main wheels 2b. Each of the pair of left and right drive units 14 includes a base plate 14 a, an arm 14 b, a drive wheel 14 c, and a motor 15 . The base plate 14a is fixed to the frame of the vehicle body 2a, whereby the drive unit 14 is attached to the wheelchair section 2. The arm 14b is provided on a surface of the base plate 14a facing the inside of the vehicle. The arm 14b is fixed to the base plate 14a so as to be swingable up and down. A motor 15 and a drive wheel 14c are provided at the tip of the arm 14b. The arm 14b supports the drive wheel 14c so as to be rotatable. The arm 14b elastically biases the drive wheel 14c downward. As a result, the arm 14b presses the drive wheel 14c against the road surface to bring it into contact with the road.

[0022] The motor 15 is an in-wheel motor and is provided inside the drive wheel 14c. A rotor (not shown) of the motor 15 can rotate integrally with the drive wheel 14c. A stator (not shown) of the motor 15 is fixed to the arm 14b side. This allows the motor 15 to rotate and drive the drive wheel 14c. The motor 15 is connected to a battery, a control device, etc. in the control box 6 via a cable (not shown). The cable is inserted into the arm 14b and connects the motor 15 to the control box 6.

[0023] The drive wheel 14c is supported by the arm 14b so as to be rotatable about a central axis parallel to the left-right direction. The drive wheel 14c is driven to rotate by the motor 15 while in contact with the road surface. The pair of left and right motors 15 drives the pair of left and right drive wheels 14c, causing the wheelchair section 2 (vehicle body 2a) to travel.

[0024] The vehicle body 2a has a pair of left and right support pipes 2a3 that support the backrest 2a2. A pair of protrusions 2a4 that protrude rearward from the backrest 2a2 are provided at the upper ends of the pair of support pipes 2a3. The pair of protrusions 2a4 are pipes with openings at their rear ends. The first operating portion 10 and the second operating portion 12 are provided on the pair of protruding portions 2a4. The first operating unit 10 is disposed on the upper left side of the backrest 2a2, and the second operating unit 12 is disposed on the upper right side of the backrest 2a2. The first operating unit 10 has a first grip 20. The second operating unit 12 has a second grip 30.

[0025] FIG. 2 is a cross-sectional view of the first operating unit 10. As shown in FIG. As shown in FIG. 2(a), the first operating unit 10 has a potentiometer 21 in addition to the first grip 20. The first grip 20 is attached to the tip of the protruding portion 2a4 on the left side of the vehicle. The first grip 20 has a tubular portion 20a and a bottom portion 20b. The bottom portion 20b closes the opening on the rear side of the tubular portion 20a. The tubular portion 20a is attached to the outer periphery of the protruding portion 2a4. The tubular portion 20a is movable while sliding on the outer periphery of the protruding portion 2a4. Therefore, the first grip 20 is movable along the axial direction of the protrusion 2a4. The protrusion 2a4 extends in the front-rear direction. Therefore, the first grip 20 is movable in the front-rear direction relative to the vehicle main body 2a.

[0026] The potentiometer 21 is a sensor (first detection unit) for detecting the amount of displacement in the front-rear direction of the first grip 20. The potentiometer 21 is provided inside the protrusion 2a4. The potentiometer 21 includes a main body 21a and a rod 21b. The main body 21a is fixed to the protrusion 2a4. The rod 21b extends rearward from the main body 21a. The rod 21b passes through the inside of the cylindrical portion 20a and the protruding portion 2a4. The rod 21b is movable in the axial direction relative to the main body 21a. The potentiometer 21 detects and outputs the amount of displacement of the rod 21b in the axial direction. A tip end 21b1 of the rod 21b is fixed to the bottom portion 20b. Therefore, the rod 21b moves in the front-rear direction together with the first grip 20. This allows the potentiometer 21 to detect the amount of displacement of the first grip 20 in the front-rear direction relative to the vehicle body 2a. The potentiometer 21 is connected to a control device (to be described later) in the control box 6. The output of the potentiometer 21 is given to the control device.

[0027] In addition to the potentiometer 21, a sleeve 22, a front bush 23, a rear bush 24, and a spring 25 are provided inside the protruding portion 2a4. The sleeve 22 is a cylindrical member that is inserted into and fixed to the inner circumferential surface of the protruding portion 2a4. The front bushing 23 , the rear bushing 24 , and the spring 25 are disposed on the inner circumferential side of the sleeve 22 .

[0028] The front bushing 23 has a cylindrical portion 23a and a bottom portion 23b. The cylindrical portion 23a is inserted into and fixed to the inner circumferential surface 22a of the sleeve 22. The bottom portion 23b is provided at an opening on the front side of the cylindrical portion 23a. The bottom portion 23b has a center hole 23b1. The rod 21b is inserted through the center hole 23b1. The rear bushing 24 has a cylindrical portion 24a and a bottom portion 24b. The cylindrical portion 24a is inserted into and fixed to the inner circumferential surface 22a of the sleeve 22. The bottom portion 24b is provided at an opening on the rear side of the cylindrical portion 24a. The bottom portion 24b has a center hole 24b1. The rod 21b is inserted through the center hole 24b1.

[0029] The spring 25 is disposed between the front bushing 23 and the rear bushing 24. Therefore, the rod 21b passes through the front bushing 23, the rear bushing 24, and the spring 25. The rod 21b is provided with a front retainer 26a, a front snap ring 27a, a rear retainer 26b, and a rear snap ring 27b. The front retaining ring 27a is provided on the front side of the spring 25. The front retaining ring 27a is fixed to the rod 21b. The front retaining ring 27a is fitted into a circumferential groove provided in the rod 21b. Therefore, the front retaining ring 27a can move integrally with the rod 21b in the axial direction. The rear retaining ring 27b is provided on the rear side of the spring 25. The rear retaining ring 27b is also fixed to the rod 21b. The rear retaining ring 27b is fitted into a circumferential groove provided in the rod 21b. Therefore, the rear retaining ring 27b can move integrally with the rod 21b in the axial direction. In other words, the front retaining ring 27a and the rear retaining ring 27b are fixed to the rod 21b with a fixed distance in the axial direction.

[0030] The front retainer 26a, the rear retainer 26b, and the spring 25 are disposed between the front retaining ring 27a and the rear retaining ring 27b. The front retainer 26a and the rear retainer 26b are annular members through which the rod 21b passes. The front retainer 26a and the rear retainer 26b hold the front end surface and the rear end surface of the spring 25. The front retainer 26a is interposed between the front bushing 23 and the front end surface of the spring 25. The rear retainer 26b is interposed between the rear bushing 24 and the rear end surface of the spring 25.

[0031] 2(a) shows the case where the first grip 20 is in the neutral position. The first grip 20 is in the neutral position when it is not being held by the operator or when the operator is not inputting an operating force. When the first grip 20 is in the neutral position, the spring 25 biases the front retainer 26a toward the front bush 23. The spring 25 also biases the rear retainer 26b toward the rear bush 24. At this time, the front retainer 26a abuts against the cylindrical portion 23a of the front bush 23. The rear retainer 26b abuts against the cylindrical portion 24a of the rear bush 24. That is, when the first grip 20 is in the neutral position, the distance between the front retainer 26 a and the rear retainer 26 b is shorter than the free length of the spring 25 .

[0032] FIG. 2(b) shows a case where the first grip 20 has moved forward from the neutral position. When the first grip 20 moves forward from the neutral position, the rod 21b also moves forward, causing the output of the potentiometer 21 to change. When the first grip 20 and rod 21b move forward from the neutral position, the spring 25 is pressed forward by the rear retainer 26b and rear snap ring 27b. As a result, the rear retainer 26b moves away from the rear bush 24. When the first grip 20 moves further forward, the front snap ring 27a comes into contact with the bottom 23b of the front bush 23, as shown in FIG. 2(b). As a result, the front snap ring 27a and the front bush 23 restrict the forward movement of the rod 21b.

[0033] FIG. 2(c) shows a case where the first grip 20 has moved rearward from the neutral position. When the first grip 20 moves rearward from the neutral position, the rod 21b also moves rearward, causing the output of the potentiometer 21 to change. When the first grip 20 and rod 21b move rearward from the neutral position, the spring 25 is pressed rearward by the front retainer 26a and front snap ring 27a. As a result, the front retainer 26a moves away from the front bushing 23. When the first grip 20 moves further rearward, the rear snap ring 27b comes into contact with the bottom portion 24b of the rear bushing 24, as shown in FIG. 2(c). As a result, the rear snap ring 27b and the rear bushing 24 restrict the rearward movement of the rod 21b.

[0034] With the above-described configuration, the first grip 20 can be elastically moved in the front-rear direction by the spring 25 around the neutral position. Furthermore, the range of movement of the first grip 20 and the rod 21b in the front-rear direction is limited by the front bushing 23, the rear bushing 24, the front retaining ring 27a, and the rear retaining ring 27b.

[0035] The second operating unit 12 has the same configuration as the first operating unit 10, and includes a potentiometer 31 in addition to a second grip 30 (FIG. 2). The second grip 30 is attached to the tip of the protrusion 2a4 on the right side of the vehicle, and is provided so as to be movable in the front-rear direction relative to the vehicle body 2a. The potentiometer 31 is a sensor (second detection unit) for detecting the amount of displacement of the second grip 30 in the front-rear direction relative to the vehicle body 2a. The output of the potentiometer 31 is given to the control device.

[0036] As shown in FIG. 1, the control box 6 is fixed to the frame portion on the lower right side of the seat portion 2a1. The control box 6 houses a battery, a control device for controlling each part, and the like.

[0037] FIG. 3 is a block diagram showing an example of a configuration for controlling the operation of the motor in the electric wheelchair 1. As shown in FIG. 3, the electric wheelchair 1 includes a battery 16 and a control device 18. The battery 16 and the control device 18 are housed in a control box 6. The battery 16 supplies power to the pair of motors 15 and each part that requires operating power. The control device 18 has a function of controlling the drive mechanism 4 (the pair of motors 15) by giving a command value to the drive mechanism 4, thereby controlling the speed of the vehicle body 2a.

[0038] The drive mechanism 4 including the pair of motors 15 has a pair of drive circuits 34. Furthermore, each of the pair of motors 15 includes a motor body 15a and a rotation detector 15b. The motor body 15a includes the main components of the motor, such as a rotor and a stator. The rotation detector 15b is, for example, a Hall sensor provided on the motor body 15a. The rotation detector 15b detects the rotation state of the rotor of the motor body 15a. The rotation detector 15b is connected to the drive circuit 34 and the control device 18. The output of the rotation detector 15b is provided to the drive circuit 34 and the control device 18.

[0039] The pair of drive circuits 34 are, for example, inverters. The pair of drive circuits 34 may be housed in the control box 6, or may be provided on the base plate 14a or the arm 14b. The pair of drive circuits 34 are connected to the control device 18, the battery 16, and the pair of motors 15. One of the pair of drive circuits 34 is connected to the left motor 15. The other of the pair of drive circuits 34 is connected to the right motor 15. The pair of drive circuits 34 provide power from the battery 16 to the pair of motors 15. The pair of drive circuits 34 have the function of providing drive power to the pair of motors 15 based on the speed command value given by the control device 18 and the output of the rotation detector 15b, and controlling the motors 15 so that they rotate at the speed indicated by the speed command value.

[0040] The pair of drive circuits 34 and the pair of motors 15 (motor bodies 15a) are connected by a pair of power lines 34a. The pair of power lines 34a are provided with a pair of current detectors 36. The pair of current detectors 36 are current sensors that detect the current flowing through the pair of power lines 34a. In other words, the pair of current detectors 36 detect the current flowing through the pair of motors 15. The pair of current detectors 36 are connected to the control device 18. The outputs of the pair of current detectors 36 are provided to the control device 18. The first operating unit 10 and the second operating unit 12 are also connected to the control device 18. As described above, the outputs of the first operating unit 10 (the potentiometer 21) and the second operating unit 12 (the potentiometer 31) are provided to the control device 18.

[0041] The control device 18 is configured by a computer or the like that includes a processing unit 38 consisting of a processor or the like, and a storage unit 40 consisting of a memory, a hard disk, or the like. The storage unit 40 stores computer programs and necessary information to be executed by the processing unit 38. The processing unit 38 executes computer programs stored in a computer-readable, non-transitory recording medium such as the storage unit 40, thereby realizing the various processing functions of the control device 18.

[0042] [Processing performed by the processing unit] FIG. 4 is a diagram showing a state in which the operator operates the electric wheelchair 1. As shown in FIG. An operator A of the electric wheelchair 1 holds the first grip 20 of the first operating unit 10 and the second grip 30 of the second operating unit 12 with his / her left and right hands, and operates the electric wheelchair 1 by pushing the electric wheelchair 1 from behind. At this time, the first grip 20 and the second grip 30 move relative to the vehicle body 2a in the longitudinal direction. The first operating unit 10 and the second operating unit 12 provide outputs corresponding to the movements of the first grip 20 and the second grip 30 to the control device 18. The control device 18 generates speed command values ​​based on the outputs from the first operating unit 10 and the second operating unit 12, and provides the speed command values ​​to a pair of drive circuits .

[0043] The output from the first operating unit 10 indicates the amount of longitudinal displacement of the first grip 20 relative to the vehicle body 2a, and the output from the second operating unit 12 indicates the amount of longitudinal displacement of the second grip 30 relative to the vehicle body 2a. The control device 18 determines the amount of displacement of the first grip 20 in the front-rear direction and the amount of displacement of the second grip 30 in the front-rear direction based on the output of the first operating unit 10 and the output of the second operating unit 12. The displacement amount is the distance between a reference position (e.g., a neutral position) set in advance within the movable range of both grips 20, 30 and the current positions of both grips 20, 30. When the reference position and the current positions coincide in the front-to-rear direction, the displacement amount is 0. In the following description, the displacement amount (first displacement amount) of the first grip 20 in the front-rear direction is referred to as displacement amount x UI_LThe amount of displacement of the second grip 30 in the front-rear direction (second displacement amount) is called a displacement amount x UI_R That's what they say.

[0044] The control device 18 calculates the displacement x UI_L and displacement x UI_R The control device 18 acquires the displacement amount x discretely over time and stores it in the storage unit 40 or the like. UI_L and displacement x UI_R When calculating the differential value of x, etc., the stored displacement x UI_L and displacement x UI_R Refer to.

[0045] When the operator A holds and operates the first operating unit 10 and the second operating unit 12, the control device 18 calculates the displacement x UI_L and displacement x UI_R The drive mechanism 4 is controlled so that the movement of the vehicle body 2a relative to the load imitates the mechanical impedance characteristics. That is, the control device 18 controls the drive mechanism 4 so that the distance H between the first grip 20 (second grip 30) and the vehicle body 2a is constant, while reproducing a movement in which the first grip 20 (second grip 30) and the vehicle body 2a are connected by a virtual spring 42 and a virtual damper 44, as shown in FIG.

[0046] To control the drive mechanism 4 so that the distance H between the first grip 20 (second grip 30) and the vehicle body 2a is constant, the displacement x UI_L and displacement x UI_R This includes controlling the voltage to maintain the voltage at 0 or a predetermined set value. As a result, when the operator A moves forward and presses the first grip 20 and the second grip 30 forward, the control device 18 calculates the displacement x of the first grip 20 and the second grip 30 that are pressed forward. UI_L and displacement x UI_R The drive mechanism 4 is controlled in response to the change in speed so as to move the vehicle body 2a forward.

[0047] FIG. 5 is a block diagram showing an example of the processing contents executed by the processing unit 38 of the control device 18. As shown in FIG. The processing unit 38 has the function of executing a generation process 51 and an external force calculation process 50 . The generation process 51 calculates the external force acting on the vehicle body 2a and the displacement x UI_L and displacement x UI_R This is a process of generating a speed command value based on the above. The external force calculation process 50 is a process for obtaining an external force acting on the vehicle body 2 a used in the generation process 51 . The generation process 51 includes a thrust force calculation process 52 , a command value generation process 54 , a turning speed calculation process 56 , and a turning force calculation process 58 . The processing unit 38 starts the process of controlling the speed of the vehicle body 2a, thereby executing the generation process 51 and the external force calculation process 50 as needed.

[0048] The outputs of the first operating unit 10 and the second operating unit 12 are used in the thrust calculation process 52 and the turning speed calculation process 56 . The outputs of the pair of rotation detectors 15b are used in the thrust force calculation process 52 and the turning force calculation process 58. The outputs of the pair of current detection units 36 are used in the external force calculation processing 50.

[0049] [External force calculation processing] The external force calculation process 50 is a process for determining the external force acting on the vehicle body 2a. An operator A grips the first operating unit 10 and the second operating unit 12 and operates the electric wheelchair 1 by pushing the electric wheelchair 1 from behind. At this time, apart from the displacement of both grips 20, 30, an external force due to the operation of operator A acts on vehicle body 2a via first operating unit 10 and second operating unit 12. The processing unit 38 executes an external force calculation process 50 to determine the external force acting on the vehicle body 2a.

[0050] Fig. 6 is a plan view of the electric wheelchair 1. Note that Fig. 6 shows only the main parts of the electric wheelchair 1 in a schematic manner. 6, point P is a point on the rotation axis C1 of the pair of drive wheels 14c, and is the midpoint between the pair of drive wheels 14c. In the following description, the direction around the central axis that passes through point P and extends in the vertical direction is referred to as the turning direction. The control device 18 determines the external force acting on the vehicle body 2a by dividing it into an external force in the front-rear direction and an external force in the turning direction.

[0051] When the operator A attempts to turn the vehicle body 2a in a predetermined direction via the operation units 10, 12 of the electric wheelchair 1 during speed control, the pair of drive circuits 34 controls the pair of motors 15 to generate torque for turning in the direction opposite to the predetermined direction in order to maintain the operating state based on the speed command value. Therefore, the current value flowing through the pair of motors 15 indicates the external force acting on the vehicle body 2a via the operation units 10, 12 (external force due to the operation of the operator A).

[0052] For example, let us consider a case where, for a stopped electric wheelchair 1, operator A attempts to rotate the vehicle body 2a counterclockwise around the central axis passing through point P by pulling the first operating unit 10 backward and pushing the second operating unit 12 forward, as shown in Figure 6. In this case, it is assumed that a speed command value of 0 is given to the pair of drive circuits 34.

[0053] When the vehicle body 2a is turned by the operation of the operator A, the drive wheel 14c on the left side of the vehicle moves backward, and the drive wheel 14c on the right side of the vehicle moves forward. At this time, the drive circuit 34 that controls the drive wheel 14c on the left side of the vehicle controls the motor 15 on the left side of the vehicle so as to generate torque that moves the drive wheel 14c on the left side of the vehicle forward. Further, the drive circuit 34 that controls the drive wheel 14c on the right side of the vehicle controls the motor 15 on the right side of the vehicle so as to generate torque that moves the drive wheel 14c on the right side of the vehicle backward.

[0054] At this time, the current flowing through the pair of motors 15 is supplied in accordance with the turning operation of the vehicle body 2a. Therefore, the current flowing through the pair of motors 15 represents the external force acting on the vehicle body 2a via both operation units 10, 12. In the above example, the electric wheelchair 1 is described as being stopped, but the same applies to the case of an electric wheelchair 1 that is traveling while its speed is being controlled. Therefore, the processing unit 38 calculates the external force acting on the vehicle body 2a based on the following equation (1).

[0055]

number

[0056] In formula (1), F op is the external force in the forward / backward direction, τ op is the external force in the turning direction, r is the radius of the drive wheels 14c, W is the distance between the pair of drive wheels 14c (see FIG. 6), K t is the torque constant of the motor 15 (torque generated by the motor per unit current), I R is the current value obtained from the output of the current detection unit 36 ​​on the right side of the vehicle, and I L is the current value determined from the output of the current detector 36 on the left side of the vehicle. r,W,K t is a constant and is stored in advance in the storage unit 40. In equation (1), the external force F in the forward / backward direction is calculated based on the total torque generated by the pair of motors 15. op is calculated, and the external force τ in the turning direction is calculated based on the difference between the torques generated by the pair of motors 15. op is required.

[0057] In the external force calculation process 50, the processing unit 38 calculates the current value I , which indicates the current flowing through the pair of motors 15, as shown in the above formula (1). R , current value I L Based on this, the external force F in the forward and backward direction OP , external force τ in the rotation direction OP Ask for. In this way, in the external force calculation process 50, the external force acting on the vehicle body 2a is calculated as the external force F in the front-rear direction. OP and the external force τ in the rotation direction OPIt can be calculated by dividing it into two parts.

[0058] [Thrust force calculation processing] The thrust calculation process 52 calculates a target thrust F th This is the process of finding the answer. In the thrust calculation process 52, the processing unit 38 calculates the target thrust F based on the following equation (2): th Ask for.

[0059]

number

[0060] Equation (2) is the Laplace transformed target thrust F th Shows. In equation (2), K is a virtual spring coefficient, D is a virtual damper coefficient, μ is a friction coefficient, M is a virtual mass of the electric wheelchair 1, v is the traveling speed of the electric wheelchair 1, α is a coefficient, s is a Laplace operator, and ω1 and ω2 are predetermined cutoff frequencies.

[0061] As shown in equation (2), the thrust calculation process 52 calculates the displacement x UI_R , displacement x UI_L , the running speed of the electric wheelchair 1 v, and the external force in the forward and backward direction F op Using this, the target thrust F th is required. The first term in equation (2) shown below represents a model for realizing mechanical impedance characteristics.

[0062]

number

[0063] The spring constant K in the first term is the displacement x UI_R and displacement x UI_L The total displacement x T is multiplied by the spring constant K and the total displacement x T The product of K and K indicates an elastic term based on the amount of displacement. The spring coefficient K is the spring constant of the virtual spring 42 (FIG. 4), and is a preset constant. The damping coefficient D in the first term is the Laplace operator and the total displacement x T and are multiplied. Total displacement x T The product of the damping coefficient D and the Laplace operator represents the differential value of the displacement. Therefore, the damping coefficient D, the Laplace operator, and the total displacement x T The product of ∑ and ∑ represents a viscosity term based on the differential value of the displacement. The damper coefficient D is a coefficient indicating the viscosity of the virtual damper 44 (FIG. 4), and is a preset constant. Thus, the first term includes an elastic term based on the displacement amount and a viscous term based on the differential value of the displacement amount.

[0064] In the first term, ω1 / (s+ω1) multiplied by the damping coefficient D is a low-pass filter with a cutoff frequency of ω1. By multiplying this low-pass filter by the viscosity term, the total displacement x T This suppresses the relatively high frequency noise contained in the

[0065] In addition, in the above item 1, the displacement x of both grips 20 and 30 UI_R and displacement x UI_L The total displacement x T This is because it is in line with the calculation method for the external force FOP in the forward and backward direction, and also because the displacement x UI_R and displacement x UI_L Even if there is a slight difference between the target thrust F th (Target propulsion force F th This is because it is possible to obtain the calculation results necessary to calculate

[0066] The second term in equation (2) shown below represents the deceleration force in the front-rear direction of the vehicle body 2a.

[0067]

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[0068] The friction coefficient μ in the second term is a value for virtually setting the friction coefficient acting on the vehicle body 2a, and is a preset constant. The traveling speed v of the electric wheelchair 1 is determined based on the output of the pair of rotation detectors 15b. In other words, the pair of rotation detectors 15b constitute an acquisition unit that acquires speed information indicating the traveling speed of the vehicle body 2a.

[0069] The product of the friction coefficient μ and the traveling speed v indicates the friction force according to the speed of the electric wheelchair 1. The virtual mass M of the electric wheelchair 1 is an assumed value of the total mass of the electric wheelchair 1 and the occupant, and is a preset constant. The virtual mass M is multiplied by a Laplace operator and the traveling speed v. The product of the traveling speed v and the Laplace operator represents the differential value of the traveling speed v (the acceleration of the electric wheelchair 1). Therefore, the product of the virtual mass M, the Laplace operator, and the traveling speed v represents the deceleration force corresponding to the acceleration of the electric wheelchair 1.

[0070] The second term determines the friction force according to the speed of the electric wheelchair 1 and the deceleration force according to the acceleration of the electric wheelchair 1. The sum of these is the deceleration force in the front-rear direction of the vehicle body 2a. The deceleration force in the longitudinal direction of the vehicle body 2a obtained by the second term is added to the calculation result of the first term.

[0071] In the second term, ω2 / (s+ω2) multiplied by the virtual mass M is a low-pass filter with a cutoff frequency of ω2. This low-pass filter suppresses relatively high-frequency noise contained in the traveling speed v.

[0072] The third term in equation (2) shown below is a term for correcting for movement in the forward and backward directions. 3rd term: -αF OP

[0073] The coefficient α in the third term is the total displacement x T is a variable that changes depending on αF OP is the external force in the forward and backward direction and the total displacement x T The value that changes depending on the external force in the forward and backward direction and the total displacement xT The data is adjusted appropriately depending on the situation. αF OP Upper and lower limits are set for the speed, which makes it possible to prevent the vehicle from slowing down or accelerating more than necessary.

[0074] The processing unit 38 calculates a target thrust F based on the calculation result of the first term and the calculation results of the second and third terms. th Ask for.

[0075] [Turning speed calculation processing] The turning speed calculation process 56 calculates a target turning speed ω yaw This is the process of finding the answer. In the turning speed calculation process 56, the processing unit 38 calculates the target turning speed ω based on the following equations (3) and (4): yaw Ask for.

[0076]

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[0077] In addition, in formula (3), C comp is the gain for compliance control, I comp is the virtual inertia coefficient, D comp is the virtual damper coefficient. Gain C comp , inertia coefficient I comp is a preset constant. Damper coefficient D comp is the displacement x UI_R , displacement x UI_L , is a variable that changes depending on the damping coefficient D comp is expressed as the following equation (5).

[0078]

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[0079] In formula (5), D const and β are preset constants. As shown in equation (5), the damping coefficient D comp is the displacement x UI_R and the displacement x UI_L More specifically, the damping coefficient D comp is the displacement x UI_R and the displacement x UI_L The larger the difference between the two, the smaller the value is set. Furthermore, the damping coefficient D comp The damper coefficient D has an upper limit and a lower limit. comp When the upper limit is exceeded, the displacement x UI_R and the displacement x UI_L The upper limit is set regardless of the difference between the damper coefficient D comp When the value falls below the lower limit, the displacement x UI_R and the displacement x UI_L This sets the lower limit value regardless of the difference between the displacement x UI_R and the displacement x UI_L The difference between these is the damper coefficient D comp A dead zone is provided for

[0080] The brackets in the above formula (3) represent the external force τ in the current turning direction. OP and the external force based on the target turning speed and target turning acceleration. comp and the target turning acceleration are inertia terms, and the damper coefficient D comp The product of and the target turning speed is the viscous term. Thus, the above equation (3) includes an inertial term and an elastic term. Therefore, the processing unit 38 calculates the target rotation speed ω while reproducing the virtual inertia and the virtual damper. yaw That is, the processing unit 38 is configured to calculate the target turning speed ω by compliance control. yaw Ask for.

[0081] [Turning force calculation processing] The turning force calculation process 58 calculates the target turning speed ω yaw and a target turning force τ , which is a target value of the turning force in the turning direction of the vehicle body 2a, based on the outputs of the pair of rotation detectors 15b. yaw This is the process of finding the answer. In the turning force calculation process 58, the processing unit 38 calculates the target turning force τ based on the following equation (6): yaw Ask for.

[0082]

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[0083] In formula (6), P yaw is the proportional gain, D yaw is the differential gain, v R is the rotational speed (circumferential speed) of the right driving wheel 14c, v L is the rotational speed (circumferential speed) of the left drive wheel 14c, and ω3 is a predetermined cutoff frequency. Proportional gain P yaw , and the differential gain D yaw is a preset constant. rotational speed v R , v L is found from the outputs of the pair of rotation detectors 15b. In formula (6), (v R -v L ) / W indicates the yaw rate (current turning speed) of the vehicle body 2a. yaw -((v R -v L ) / W) is the target turning speed ω yaw and the current turning speed. Equation (6) expresses the target turning force τ yaw This shows that

[0084] The processing unit 38 calculates the target turning speed ω obtained in the turning speed calculation process 56 as shown in equation (6). yaw and the rotational speed v R , v L Based on this, the target turning force τ yaw Ask for. In other words, the processing unit 38 calculates the target turning force τ based on the external force acting on the vehicle body 2a and the outputs of the pair of rotation detectors 15b. yaw Ask for.

[0085] In addition, the differential gain Dyaw The ω3 / (s+ω3) multiplied by is a low-pass filter with a cutoff frequency of ω3. This low-pass filter is used to filter the target turning speed ω yaw and the current turning speed.

[0086] [Command value generation process] The command value generation process 54 generates a target thrust F th and the target turning force τ yaw This is a process of generating a speed command value to be given to the pair of drive circuits 34 based on the above. In the command value generation process 54, the processing unit 38 calculates the force to be the output target of the left and right drive wheels 14c based on the following equation (7).

[0087]

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[0088] In formula (7), F R is the output target force of the right drive wheel 14c, F L indicates the target output force of the left drive wheel 14c. The processing unit 38 calculates the target thrust F calculated by the thrust calculation process 52 as shown in equation (7). th and the target turning force τ calculated by the turning force calculation process 58. yaw Based on this, a force F that is an output target of the pair of drive wheels 14c is calculated. R ,F L Ask for.

[0089] The output target force F of the drive wheel 14c R ,F L After determining the speed command value, the processing unit 38 further determines the speed command value based on the following equation (8).

[0090]

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[0091] In formula (8), v CR is the speed command value given to the right-side drive circuit 34, vCL indicates the speed command value given to the drive circuit 34 on the left side.

[0092] The processing unit 38 calculates the calculated speed command value v CR ,v CL are provided to a pair of drive circuits 34. In addition, the speed command value v CR ,v CL indicates the peripheral speed of the pair of drive wheels 14c. Therefore, the processing unit 38 calculates the speed command value v CR ,v CL is converted into the number of rotations per unit time and is given to a pair of drive circuits 34. Speed ​​command value v CR ,v CL The pair of drive circuits 34 given the speed command value v CR ,v CL The pair of motors 15 are controlled and driven in accordance with the above.

[0093] As described above, the processing unit 38 of the control device 18 of this embodiment calculates the velocity command value v using a model (the first term of Equation (1)) including an elastic term based on the displacement amounts of both operation units 10 and 12 and a viscosity term based on the differential value of the displacement amounts of both operation units 10 and 12. CR ,v CL A generation process 51 is executed to generate the According to this configuration, the target thrust F is calculated using a model including an elastic term and a viscous term. th Calculate the speed command value v CR ,v CL Since the driving mechanism 4 is controlled so that the movement of the vehicle body 2a in response to the displacement of both operation units 10, 12 imitates the mechanical impedance characteristics, it is possible to control the driving mechanism 4. As a result, when the speed of the vehicle body 2a is controlled so that the distance between the operator A and the vehicle body 2a is constant, it is possible to prevent the operator A from walking at the same speed as the vehicle body 2a, thereby achieving good operability.

[0094] Furthermore, in the thrust force calculation process 52, a target thrust force F is calculated based on the calculation result of the above model and the deceleration force in the longitudinal direction obtained based on the traveling speed of the vehicle body 2a (the second term of the formula (1)). thTherefore, the target thrust force F is calculated by taking into account the deceleration based on the frictional force generated according to the speed of the vehicle body 2a and limiting the traveling speed of the vehicle body 2a. th can be obtained.

[0095] Furthermore, in the external force calculation processing 50, the external force acting on the vehicle body 2a via both operation units 10, 12 is determined based on the outputs of the pair of current detection units . Furthermore, in the generation process 51, a speed command value is generated based on the calculation results using the above model and the external force determined in the external force calculation process 50. Therefore, the speed of the vehicle body 2a can be controlled based on the amount of displacement of both operation units 10, 12 and the external force acting on the vehicle body 2a.

[0096] The generation process 51 also generates a target thrust F th and a thrust calculation process 52 for calculating the target turning force τ yaw and a turning force calculation process 58 for calculating the target thrust F th and target turning force τ yaw The speed command values ​​v for the pair of motors 15 are calculated based on the CR, v CL and a command value generation process 54 for generating a command value. This allows the target force for moving the vehicle body 2a to be determined separately as a propulsive force in the front-rear direction and a turning force in the turning direction, thereby enabling the speeds of the pair of motors 15 to be controlled appropriately.

[0097] Furthermore, in the external force calculation process 50, the external force F OP and the external force τ in the rotation direction OP In the thrust calculation process 52, the calculation result by the above model and the external force F in the forward and backward direction are calculated. OP and based on the target thrust F th In the turning force calculation process 58, the external force τ in the turning direction is calculated. OP and the output of the pair of rotation detectors 15b, a target turning force τ yaw is required. In this way, the external force acting on the vehicle body 2a is the external force FOP and the external force τ in the rotation direction OP By dividing the target thrust force and the target turning force, the target propulsive force and the target turning force can be calculated with higher accuracy.

[0098] In this embodiment, in the turning speed calculation process 56, the external force acting on the vehicle body 2a and the displacement x UI_R and displacement x UI_L and the difference between the target turning speed and the target turning speed. Furthermore, in the turning force calculation process 58, the target turning force τ is calculated based on the target turning speed and the output of the pair of rotation detectors 15b. yaw is required. In this embodiment, the displacement x UI_R and displacement x UI_L The damping coefficient D is determined by the difference between comp Therefore, the displacement x UI_R and the displacement x UI_L The difference between these is the damper coefficient D comp This provides a dead zone for the displacement x UI_R and the displacement x UI_L By imposing a restriction on the movement in the turning direction based on the difference between the values, it is possible to prevent the operator A from making an unintended movement.

[0099] 〔others〕 The embodiments disclosed herein are illustrative in all respects and are not restrictive. For example, in the above embodiment, the vehicle main body 2a is provided with the first operating unit 10 and the second operating unit 12, but it is sufficient that at least one of them is provided as an operating unit.

[0100] Furthermore, in the above embodiment, the processing unit 38 generates a speed command value and provides the speed command value to the pair of drive circuits 34 to drive and control the pair of motors 15, but the processing unit 38 may be configured to generate a current command value indicating the current value to be provided to the motor 15 and provide the current command value to the pair of drive circuits 34 to drive and control the pair of motors 15. In the above embodiment, the motor 15 is an in-wheel motor provided inside the drive wheel 14c, but the motor 15 may be provided outside the drive wheel 14c. In this case, the motor 15 drives the drive wheel 14c from the outside.

[0101] Furthermore, in the above embodiment, the case of the electric wheelchair 1 has been exemplified, but the present invention can also be applied to electric vehicles other than wheelchairs, such as carts and wagons, which are provided with an electric drive mechanism.

[0102] The scope of the present invention is not limited to the above-described embodiments, but includes all modifications within the scope of equivalents to the configurations described in the claims. [Explanation of symbols]

[0103] 1 Electric wheelchair 2 Wheelchair section 2a Vehicle body 2a1 seat 2a2 backrest 2a3 support pipe 2a4 Protrusion 2b Main wheel 2c Caster 4 Drive mechanism 6 Control box 10 First operating unit 12 Second operating unit 14 Drive unit 14a Base plate 14b Arm 14c Drive wheel 15 Motor 15a Motor body 15b Rotation detector 16 battery 18 control device 20 first grip 20a Cylinder part 20b Bottom part 21 potentiometer 21a main body 21b rod 21b1 Tip portion 22 Sleeve 22a Inner peripheral surface 23 Front bush 23a Cylindrical portion 23b Bottom portion 23b1 Center hole 24 Rear bush 24a Cylindrical portion 24b Bottom 24b1 Center hole 25 Spring 26a Front retainer 26b Rear retainer 27a Front retaining ring 27b Rear retaining ring 30 Second grip 31 potentiometer 34 drive circuit 34a power line 36 Current detection unit 38 Processing unit 40 Storage unit 42 Spring 44 Damper 50 External force calculation processing 52 Thrust force calculation processing 54 Command value generation processing 56 Turning speed calculation processing 58 Turning force calculation processing A Operator C1 rotation axis

Claims

1. The vehicle body, a drive mechanism for driving the vehicle body; a control device that controls the drive mechanism by providing a command value to the drive mechanism; a first operating unit including a first grip that is held by an operator and that receives an operation of pushing the vehicle body by the operator and that is movable in a front-rear direction of the vehicle body, and a first detection unit that detects a first displacement amount of the first grip in the front-rear direction relative to the vehicle body; an acquisition unit that acquires speed information indicating a traveling speed of the vehicle body; Equipped with The control device a processing unit that executes a generation process of generating the command value using a model including an elastic term based on the first displacement amount and a viscosity term based on a differential value of the first displacement amount, The generation process includes: a thrust calculation process for calculating a target thrust, which is a target value of the thrust in the longitudinal direction, using the model; a command value generation process for generating the command value based on the target thrust, In the thrust calculation process, the target thrust is calculated based on the calculation result of the model and the deceleration force in the longitudinal direction obtained based on the speed information. Electric vehicle.

2. The drive mechanism includes: A pair of left and right drive wheels; a pair of motors that drive the pair of drive wheels; a pair of drive circuits that drive a pair of motors based on the command values; The electric vehicle according to claim 1 .

3. The vehicle body, a drive mechanism for driving the vehicle body; a control device that controls the drive mechanism by providing a command value to the drive mechanism; a first operating unit including a first grip that is held by an operator and that receives an operation of pushing the vehicle body by the operator and that is movable in a front-rear direction of the vehicle body, and a first detection unit that detects a first displacement amount of the first grip in the front-rear direction relative to the vehicle body; Equipped with The control device a processing unit that executes a generation process of generating the command value using a model including an elastic term based on the first displacement amount and a viscosity term based on a differential value of the first displacement amount, The drive mechanism includes: A pair of left and right drive wheels; a pair of motors that drive the pair of drive wheels; a pair of drive circuits that drive a pair of motors based on the command values; further comprising a pair of current detection units for detecting currents flowing through the pair of motors; The processing unit executes an external force calculation process to determine an external force acting on the vehicle body based on the pair of current values ​​detected by the pair of current detection units; In the generation process, the command value is generated based on the calculation result of the model and the external force. Electric vehicle.

4. a pair of rotation detectors for detecting the rotation speeds of the pair of motors; The generation process includes: a thrust calculation process for calculating a target thrust, which is a target value of the thrust in the longitudinal direction, using the model; a turning force calculation process for calculating a target turning force, which is a target value of the turning force in the turning direction of the vehicle body, based on the external force and the outputs of the pair of rotation detectors; a command value generation process for generating a pair of the command values ​​for the pair of motors based on the target propulsive force and the target turning force. The electric vehicle according to claim 3 .

5. the external force includes an external force in the front-rear direction and an external force in the turning direction, In the thrust calculation process, the target thrust is calculated based on a calculation result of the model and the external force in the longitudinal direction; In the turning force calculation process, the target turning force is calculated based on the external force in the turning direction and the outputs of the pair of rotation detectors. The electric vehicle according to claim 4.

6. a second operating unit including a second grip movable in the front-rear direction and a second detection unit configured to detect a second displacement amount of the second grip relative to the vehicle body in the front-rear direction; the first operating unit is provided on the left side of the vehicle body, The second operation unit is provided on the right side of the vehicle body, the generation process includes a turning speed calculation process of calculating a target turning speed that is a target value of the turning speed in the turning direction based on the external force and a difference between the first displacement amount and the second displacement amount, In the turning force calculation process, the target turning force is calculated based on the target turning speed and the outputs of the pair of rotation detectors. The electric vehicle according to claim 5 .

7. Further including a wheelchair section; The vehicle body is the vehicle body of the wheelchair unit. The electric vehicle according to any one of claims 1 to 6.

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