Four-wheel steering electric vehicle and its drive method

Abstract

To provide a four-wheel turning electric automobile and a driving method for the automobile.SOLUTION: A four-wheel turning electric automobile includes a vehicle body, front wheels, a front wheel steering motor, rear wheels, a rear wheel steering motor, a main power motor, a vehicle speed detection unit, and a control unit. The front wheel steering motor is connected to the front wheels and is used to drive turning of the front wheels. The rear wheel steering motor is connected to the rear wheels and is used to drive turning of the rear wheels. The main power motor is installed in the vehicle body and is used to drive rotation of the front wheels and rear wheels. The vehicle speed detection unit is used to detect a vehicle speed of the vehicle body. The control unit is used to control turning of the front wheels and turning of the rear wheels in an identical direction according to a fact that the vehicle speed is larger than a predesignated speed value and to control the turning of the front wheels and the turning of the rear wheels in opposite directions according to a fact that the vehicle speed is smaller than the predesignated speed value.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a four-wheel-steering electric vehicle and a driving method thereof.

Background Art

[0002] When an electric vehicle is running on the ground, it may encounter various road conditions such as narrow roads and sharp-angle curves. Narrow roads and sharp-angle curves increase the difficulty of operating an electric vehicle, and more effective operation and steering mechanisms are also required for movement in narrow spaces and rugged terrain. Therefore, proposing an electric vehicle that can improve the above-mentioned problems is one of the goals of the efforts of those skilled in the art. Currently, related problems are being addressed by a technology that interlocks the front and rear wheel groups with a link mechanism or gears to reverse the front and rear wheel groups.

[0003] Taiwan Patent Publication No. I593587 proposes a steering device. The steering device includes a steering link, a plurality of rotating wheels, a steering drive assembly, a hydraulic steering group, two auxiliary rotating wheels, and a controller. These first rotating wheels are respectively provided on the steering link. The steering drive assembly is connected to the link body. The steering drive assembly is used to drive the steering of these first rotating wheels to generate a steering angle signal. The hydraulic steering group includes two hydraulic cylinders and two second steering arms connected to the two hydraulic cylinders. The two auxiliary rotating wheels are connected to the two second steering arms. The controller is connected to the steering drive assembly and the two hydraulic cylinders. The controller drives the two hydraulic cylinders to expand and contract based on the steering angle signal, and drives the two auxiliary rotating wheels to be individually steered by the two auxiliary steering arms.

[0004] Taiwan Patent Publication No. M606240 proposes a four-wheel steering mechanism. The four-wheel steering mechanism mainly comprises a carriage that independently drives the four front and rear wheels. A steering mechanism is provided on the chassis side of the carriage. The steering mechanism includes a steering power source. The steering power source drives two racks, each moving the two racks in opposite directions. Links are pivotally attached to the ends of each of the two racks. The two links are pivotally attached to the steering shafts of the front and rear wheels on their respective sides. This shortens the transmission distance by side mounting, reduces torque and power demand, saves power output and power source volume, increases the usable space of the carriage chassis, and achieves a load balancing effect.

[0005] Taiwan Patent Publication No. I426408 proposes a simulation system for the steering performance of a four-wheel steering vehicle. The four-wheel steering vehicle steering performance simulation system includes a vehicle planar motion steering performance simulation module, a tire slip simulation module, a wheel forward force simulation module, and a steering motor output power simulation module. In the four-wheel steering vehicle steering performance simulation system, freely configurable parameters include tire longitudinal force, tire lateral force, return torque, steering angle, vehicle weight, and tire rotational inertia, thereby simulating various output performances during vehicle steering.

[0006] U.S. Patent Publication US20180086372 proposes a steering control device for a vehicle. The steering control device includes a control means configured to calculate a target rearward steering angle expressed as a function of input parameters, including steering wheel angle, and a rear-wheel steering means arranged to rotate the rear wheels of the vehicle based on the target rearward steering angle. The control means performs a correction process on a correction function when the vehicle is in an over-steering state and correction conditions are met in which counter-steering is applied to the driving. The absolute value of the target rearward steering angle calculated when the correction process is performed on the same input parameters is smaller than the absolute value of the target rearward steering angle calculated before the correction process is performed.

[0007] U.S. Patent Publication US20150307125 proposes a vehicle steering control device. The vehicle steering control device includes a rotation angle changing means, a first rotation response changing means for changing the gain of the vehicle's yaw rate in response to a steering operation, a second rotation response changing means for changing the gain of the vehicle's yaw angular velocity, and a rear-wheel steering means for changing the vehicle's yaw angular velocity. When the curvature of the travel path is less than or equal to a first reference value, at least one of the rotation angle changing means and the rear-wheel steering means is controlled. Thus, when the width of the travel path is small, the gain of lateral acceleration is increased compared to when the width of the travel path is large, resulting in an increased gain of yaw rate. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Embodiments of the present invention propose a four-wheel steering electric vehicle and a driving method thereof, which can improve upon the aforementioned well-known problems. [Means for solving the problem]

[0009] One embodiment of the present invention proposes a four-wheel steering electric vehicle. The four-wheel steering electric vehicle includes a vehicle body, front wheels, front wheel steering motors, rear wheels, rear wheel steering motors, a main power motor, a vehicle speed sensing unit, and a control unit. The front wheels are connected to the vehicle body. The front wheel steering motors are connected to the front wheels and are used to drive the steering of the front wheels. The rear wheels are connected to the vehicle body. The rear wheel steering motors are connected to the rear wheels and are used to drive the steering of the rear wheels. The main power motors are located in the vehicle body and are used to drive the rotation of the front and rear wheels. The vehicle speed sensing unit is used to detect the vehicle speed of the vehicle body. The control unit is used to control the steering of the front wheels and rear wheels in the same direction when the vehicle speed is greater than a preset speed value, and to control the steering of the front wheels and rear wheels in opposite directions when the vehicle speed is less than a preset speed value.

[0010] Another embodiment of the present invention proposes a driving method for a four-wheel steering electric vehicle. The driving method is applied to the aforementioned four-wheel steering electric vehicle. The driving method includes the following steps: controlling the steering of the front wheels and rear wheels in the same direction when the vehicle speed is greater than a preset speed value, and controlling the steering of the front wheels and rear wheels in opposite directions when the vehicle speed is less than a preset speed value.

[0011] To better understand the above and other aspects of the present invention, examples are given below and described in detail with reference to the accompanying drawings: [Brief explanation of the drawing]

[0012] [Figure 1] This shows a functional block diagram of a four-wheel steering electric vehicle according to one embodiment of the present invention.

[0013] [Figure 2] Figure 1 shows a schematic diagram of a four-wheel steering electric vehicle.

[0014] [Figure 3A] Figure 1 shows a schematic diagram of the front and rear wheels steering in opposite directions.

[0015] [Figure 3B] Figure 1 shows a schematic diagram of the front and rear wheels steering in the same direction.

[0016] [Figure 4] Figure 1 shows a flowchart illustrating the drive mechanism of a four-wheel steering electric vehicle. [Modes for carrying out the invention]

[0017] Referring to Figures 1 to 3B, Figure 1 shows a functional block diagram of a four-wheel steering electric vehicle 100 according to one embodiment of the present invention, Figure 2 shows a partial schematic diagram of the four-wheel steering electric vehicle 100 of Figure 1, Figure 3A shows a schematic diagram of the front wheels 110A and rear wheels 110B steering in opposite directions as in Figure 1, and Figure 3B shows a schematic diagram of the front wheels 110A and rear wheels 110B steering in the same direction as in Figure 1.

[0018] As shown in Figure 1, the four-wheel steering electric vehicle 100 comprises a vehicle body 105, at least one front wheel 110A, at least one rear wheel 110B, a front wheel steering motor 120A, a rear wheel steering motor 120B, a main power motor 130, a vehicle speed sensing unit 140, a control unit 150, a remote control signal receiving unit 160, a front wheel steering motor driver 170A, a rear wheel steering motor driver 170B, a main power motor driver 170C, a control interface 175, a battery management system 180, a front wheel linkage mechanism 190A, a rear wheel linkage mechanism 190B, a front wheel attitude detection unit 195A, and a rear wheel attitude detection unit 195B.

[0019] As shown in Figure 1, the four-wheel steering electric vehicle 100 is, for example, an agricultural electric vehicle. The body 105 is, for example, the casing of the four-wheel steering electric vehicle 100. The number of front wheels 110A is, for example, at least two. The number of rear wheels 110B is, for example, at least two.

[0020] At least one of the vehicle speed sensing unit 140, control unit 150, remote control signal receiving unit 160, front wheel steering motor driver 170A, rear wheel steering motor driver 170B, main power motor driver 170C, front wheel attitude detection unit 195A, and rear wheel attitude detection unit 195B is a physical circuit formed using a semiconductor process, such as a semiconductor chip or semiconductor package.

[0021] As shown in FIG. 1, the front wheel 110A is connected to the vehicle body 105. The front wheel steering motor 120A is connected to the front wheel 110A and is used to drive the steering of the front wheel of the front wheel 110A. The rear wheel 110B is connected to the vehicle body 105. The rear wheel steering motor 120B is connected to the rear wheel 110B and is used to drive the rear wheel steering of the rear wheel 110B. The main power motor 130 is disposed on the vehicle body 105 and is used to drive the rotation of the front wheel 110A and the rear wheel 110B. The vehicle speed detection unit 140 is used to detect the vehicle speed V of the vehicle body 105. The control unit 150 controls the front wheel steering of the front wheel 110A and the rear wheel steering of the rear wheel 110B in the same direction (shown in FIG. 3B) in response to the vehicle speed V being greater than a preset speed value, and controls the front wheel steering of the front wheel 110A and the rear wheel steering of the rear wheel 110B in the opposite direction (shown in FIG. 3A) in response to the vehicle speed V being less than the preset speed value.

[0022] The preset speed value is 25 kilometers per hour (km / hr) to 35 km / hr, for example, 25 km / hr, 26 km / hr, 27 km / hr, 28 km / hr, 29 km / hr, 30 km / hr, 31 km / hr, 32 km / hr, 33 km / hr, 34 km / hr, and 35 km / hr. When the vehicle speed V is greater than the preset speed value, the stability of the four-wheel steering electric vehicle 100 can be improved by adopting the same-direction steering. When the vehicle speed V is less than the preset speed value, the turning radius can be reduced by adopting the opposite-direction steering.

[0023] The front wheel steering of the front wheel 110A and the rear wheel steering of the rear wheel 110B can be independently controlled respectively, so that the turning radius can be greatly reduced. And through the control unit 150, the current vehicle speed V of the four-wheel steering electric vehicle 100 can be read, and different steering controls can be performed according to the vehicle speed V.

[0024] Although not shown, the four-wheel-steering electric vehicle 100 further includes a coupler, a front-wheel differential, and a rear-wheel differential. The main power motor 130 is connected to the coupler. The front-wheel differential is connected to the front wheels 110A and the coupler, and the rear-wheel differential is connected to the rear wheels 110B and the coupler. The power of the main power motor 130 is transmitted to the front-wheel differential via the coupler and then to the front wheels 110A via the front-wheel differential. Also, the power is transmitted to the rear-wheel differential via the coupler and then to the rear wheels 110B via the rear-wheel differential.

[0025] As shown in FIG. 1, the control unit 150 is, for example, a Vehicle Control Unit (VCU) that controls the entire vehicle.

[0026] In addition, the four-wheel-steering electric vehicle 100 may adopt remote remote control. For example, as shown in FIG. 1, the remote control signal receiving unit 160 is electrically connected to the control unit 150 and is used to receive a remote control signal S from a remote controller (not shown). The control unit 150 is further used to control at least one of the front-wheel steering of the front wheels 110A and the rear-wheel steering of the rear wheels 110B according to the remote control signal S.

[0027] As shown in FIG. 1, the front-wheel steering motor driver 170A is electrically connected to the front-wheel steering motor 120A to control the operation (e.g., rotation direction and rotation speed) of the front-wheel steering motor 120A. The front-wheel steering motor driver 170A is controlled by the control unit 150 and controls the operation of the front-wheel steering motor 120A according to the control signal of the control unit 150. The rear-wheel steering motor driver 170B is electrically connected to the rear-wheel steering motor 120B to control the operation (e.g., rotation direction and rotation speed) of the rear-wheel steering motor 120B. The rear-wheel steering motor driver 170B is controlled by the control unit 150 and controls the operation of the rear-wheel steering motor 120B according to the control signal of the control unit 150.

[0028] As shown in FIG. 1, the control interface 175 is, for example, a Controller Area Network (CAN bus) drive chip.

[0029] As shown in Figure 1, the battery management system 180 includes, for example, a battery and a battery management module. The battery management module is electrically connected to the battery and manages the power output / input of the battery. The battery can supply power to the main power motor driver 170C to drive the operation of the main power motor 130 (e.g., direction of rotation and rotational speed). The rotation of the front wheels 110A and rear wheels 110B is mainly driven by the main power motor 130.

[0030] As shown in Figures 2 to 3B, the front wheel linkage mechanism 190A comprises a front wheel bearer 190A1, a first front wheel link bar 190A2, and a second front wheel link bar 190A3. The front wheel bearer 190A1 is pivotally attached to the front wheel steering motor 120A, the first front wheel link 190A2 is pivotally attached to the front wheel bearer 190A1 and the front wheel 110A, and the second front wheel link bar 190A3 is pivotally attached to the front wheel bearer 190A1 and the front wheel 110A. The front wheel steering motor 120A, the front wheel bearer 190A1, the first front wheel link bar 190A2, and the second front wheel link bar 190A3 can constitute a front wheel linkage mechanism having, for example, one degree of freedom. The front wheel linkage mechanism can steer the front wheel 110A. Similarly, the rear wheel linkage mechanism 190B comprises a rear wheel bearer 190B1, a first rear wheel link bar 190B2, and a second rear wheel link bar 190B3. The rear wheel bearer 190B1 is pivotally attached to the rear wheel steering motor 120B, the first rear wheel link bar 190B2 is pivotally attached to the rear wheel bearer 190B1 and the rear wheel 110B, and the second rear wheel link bar 190B3 is pivotally attached to the rear wheel bearer 190B1 and the rear wheel 110B. The rear wheel steering motor 120B, the rear wheel bearer 190B1, the first rear wheel link bar 190B2, and the second rear wheel link bar 190B3 can constitute a rear wheel linkage mechanism having, for example, one degree of freedom. The rear wheel linkage mechanism can steer the rear wheel 110B.

[0031] As shown in Figure 3A, when the front wheel bearer 190A1 rotates relative to the front wheel steering motor 120A, it drives the first front wheel link bar 190A2 and the second front wheel link 190A3 to rotate the second front wheel 110A in the first direction. When the rear wheel bearer 190B1 rotates relative to the rear wheel steering motor 120B, it drives the first rear wheel link bar 190B2 and the second rear wheel link bar 190B3 to rotate in the second direction. The first and second directions are two opposite directions. In this embodiment, the first direction is, for example, one of clockwise and one of counterclockwise, and the second direction is, for example, the other of clockwise and one of counterclockwise.

[0032] As shown in Figure 3B, when the front wheel bearer 190A1 rotates relative to the front wheel steering motor 120A, it drives the first front wheel link bar 190A2 and the second front wheel link bar 190A3, causing the second front wheel 110A to rotate in one direction. When the rear wheel bearer 190B1 rotates relative to the rear wheel steering motor 120B, it drives the first rear wheel link bar 190B2 and the second rear wheel link bar 190B3, causing them to rotate in the same direction. The aforementioned direction is, for example, either clockwise or counterclockwise.

[0033] As shown in Figures 3A and 3B, the front wheel attitude detection unit 195A is located in the front wheel linkage mechanism 190A, for example, in the front wheel bearer 190A1 of the front wheel linkage mechanism 190A. The front wheel attitude detection unit 195A is used to detect the steering angle of the front wheels of the front wheel linkage mechanism 190A. The rear wheel attitude detection unit 195B is located in the rear wheel linkage mechanism 190B, for example, in the rear wheel bearer 190B1 of the rear wheel linkage mechanism 190B. The rear wheel attitude detection unit 195B is used to detect the steering angle of the rear wheels of the rear wheel linkage mechanism 190B. In addition, the front wheel attitude detection unit 195A and / or the rear wheel attitude detection unit 195B are, for example, gyroscopes.

[0034] Furthermore, the four-wheel steering electric vehicle 100 can also adjust the vehicle speed and / or steering pattern (for example, steering the front and rear wheels in the same direction or steering the front and rear wheels in opposite directions) according to the vertical gradient and / or lateral inclination angle of the road. For example, the front wheel attitude detection unit 195A is further used to detect the front wheel inclination of the front wheel linkage mechanism 190A. This front wheel inclination is related to and can represent the vertical gradient and / or lateral inclination angle of the road. The rear wheel attitude detection unit 195B is further used to detect the rear wheel inclination of the rear wheel linkage mechanism 190B. This rear wheel inclination is related to and can represent the vertical gradient and / or lateral inclination angle of the road. The control unit 150 can control the front wheel steering angle of the front wheel 110A and / or the rear wheel steering angle of the rear wheel 110B based on at least one of the front wheel inclination and the rear wheel inclination.

[0035] Refer to Figure 4, which shows a flowchart of the drive method for the four-wheel steering electric vehicle in Figure 1.

[0036] In step S110, the remote control signal receiving unit 160 receives the remote control signal S.

[0037] In step S120, the control unit 150 determines whether the remote control signal S includes a forward instruction. If yes, proceed to step S130; otherwise, return to step S110.

[0038] In step S130, the control unit 150 controls and operates the main power motor 130 to control the vehicle body 105 to move forward. In another embodiment, if the remote control signal S includes a reverse instruction, the control unit 150 controls and reverses the main power motor 130 to control the vehicle body 105 to move backward. The main power motor 130 may also send the vehicle speed V back to the control unit 150.

[0039] In step S140, the control unit 150 determines whether the remote control signal S includes a steering instruction. If yes, proceed to step S150; otherwise, return to step S110.

[0040] In step S150, the control unit 150 determines whether the vehicle speed V is greater than a preset speed value. If yes, proceed to step S160; otherwise, proceed to step S170.

[0041] As shown in Figure 3B, in step S160, the control unit 150 controls at least one of the steering of the front wheels 110A and the rear wheels 110B in accordance with the steering instruction of the remote control signal S1, so that the steering of the front wheels 110A and the rear wheels 110B are in the same direction.

[0042] As shown in Figure 3A, in step S170, the control unit 150 controls at least one of the steering of the front wheels 110A and the rear wheels 110B in accordance with the steering instruction of the remote control signal S1, so that the steering of the front wheels 110A and the rear wheels 110B are in opposite directions.

[0043] In short, the embodiments of this disclosure propose a four-wheel steering electric vehicle and a driving method thereof, which include front and rear wheels, with the front and rear wheels being controlled independently, thereby reducing the turning radius and improving the vehicle's handling stability.

[0044] As described above, although the present invention has been illustrated with examples, these examples are not intended to limit the present invention. Those with ordinary skill in the art to which the present invention pertains may make various modifications and finishes, provided they do not depart from the spirit and scope of the invention. Therefore, the scope of protection of the present invention is subject to the scope defined by any subsequent claims. 。 (Item 1) It is a four-wheel steering electric vehicle, The car body and, The front wheels connected to the vehicle body, A front wheel steering motor connected to the front wheel and for driving the steering of the front wheel, The rear wheels connected to the aforementioned vehicle body, A rear wheel steering motor connected to the rear wheel and for driving the steering of the rear wheel, A main power motor is positioned on the vehicle body and drives the front wheels and rear wheels to rotate, A vehicle speed sensing unit for detecting the vehicle speed of the vehicle body, Control unit and Equipped with, The control unit, In response to the vehicle speed being greater than a preset speed value, the steering of the front wheels and the steering of the rear wheels are controlled in the same direction. Used to control the steering of the front wheels and the steering of the rear wheels in opposite directions in response to the vehicle speed being less than a preset speed value, A four-wheel steering electric vehicle. (Item 2) The aforementioned preset speed value is 25 kilometers per hour (km / hr) to 35 km / hr, as described in item 1, for a four-wheel steering electric vehicle. (Item 3) The aforementioned four-wheel steering electric vehicle is an agricultural electric vehicle, as described in item 1. (Item 4) A front wheel linkage mechanism connecting the front wheel steering motor and the front wheel, A front wheel attitude detection unit is provided in the front wheel linkage mechanism for detecting the steering angle of the front wheel of the front wheel linkage mechanism, A rear wheel linkage mechanism connecting the rear wheel steering motor and the rear wheel, A rear wheel attitude detection unit is provided in the rear wheel linkage mechanism for detecting the rear wheel steering angle of the rear wheel linkage mechanism, A four-wheel steering electric vehicle as described in item 1, further including the following: (Item 5) The front wheel steering motor and the front wheel linkage mechanism connected to the front wheel, A front wheel attitude detection unit is provided in the front wheel linkage mechanism for detecting the tilt of the front wheel of the front wheel linkage mechanism, The rear wheel steering motor and the rear wheel linkage mechanism connected to the rear wheel, A rear wheel attitude detection unit is provided in the rear wheel linkage mechanism for detecting the tilt of the rear wheel of the rear wheel linkage mechanism, It further includes, The control unit further controls the steering angle of the front wheel and / or the steering angle of the rear wheel based on at least one of the front wheel tilt and the rear wheel tilt. A four-wheel steering electric vehicle as described in item 1. (Item 6) The control unit is electrically connected to the control unit and further includes a remote control signal receiving unit for receiving remote control signals, The four-wheel steering electric vehicle according to item 1, wherein the control unit is further used to control at least one of the front wheel steering of the front wheels and the rear wheel steering of the rear wheels in accordance with the remote control signal. (Item 7) A driving method for a four-wheel steering electric vehicle, applicable to any one of items 1 to 6, wherein the driving method is: In response to the vehicle speed being greater than the preset speed value, the control unit controls the steering of the front wheels and the steering of the rear wheels in the same direction. In response to the vehicle speed being less than the preset speed value, the control unit controls the steering of the front wheels and the steering of the rear wheels in opposite directions. A driving method that includes the following. (Item 8) The aforementioned preset speed value is 25 km / hr to 35 km / hr, as described in item 7 of the driving method. (Item 9) The aforementioned four-wheel steering electric vehicle is an agricultural electric vehicle, according to the drive method described in item 7. (Item 10) The front wheel attitude detection unit detects the steering angle of the front wheel of the front wheel linkage mechanism. The rear wheel attitude detection unit detects the steering angle of the rear wheels of the rear wheel linkage mechanism. The driving method described in item 7, further including the above. (Item 11) The front wheel attitude detection unit detects the tilt of the front wheel in the front wheel linkage mechanism. The rear wheel attitude detection unit detects the degree of tilt of the rear wheel in the rear wheel linkage mechanism. The control unit controls the steering angle of the front wheel and / or the steering angle of the rear wheel based on at least one of the front wheel tilt and the rear wheel tilt. The driving method described in item 7, further including the above. (Item 12) The remote control signal receiving unit receives the remote control signal. The control unit controls at least one of the front wheel steering and the rear wheel steering in accordance with the remote control signal. The driving method described in item 7, further including the above.

Claims

1. It is a four-wheel steering electric vehicle, The car body and, The front wheels connected to the vehicle body, A front wheel steering motor connected to the front wheel and for driving the steering of the front wheel, The rear wheels connected to the aforementioned vehicle body, A rear wheel steering motor connected to the rear wheel and for driving the steering of the rear wheel, A main power motor is positioned on the vehicle body and drives the front wheels and rear wheels to rotate, A vehicle speed sensing unit for detecting the vehicle speed of the vehicle body, A front wheel linkage mechanism connected to the front wheel steering motor and the front wheel, the front wheel steering motor and the front wheel being connected, A front wheel bearer pivotally attached to the aforementioned front wheel steering motor, The front wheel bearer and the first front wheel link bar pivotally attached to the front wheel, A front wheel linkage mechanism equipped with, A front wheel attitude detection unit is positioned on the front wheel bearer of the front wheel linkage mechanism and is used to detect the front wheel steering angle and front wheel tilt of the front wheel linkage mechanism, The rear wheel steering motor and the rear wheel linkage mechanism connected to the rear wheel, A rear wheel attitude detection unit is provided in the rear wheel linkage mechanism for detecting the tilt of the rear wheel of the rear wheel linkage mechanism, Control unit and Equipped with, The control unit, In response to the vehicle speed being greater than a preset speed value, the steering of the front wheels and the steering of the rear wheels are controlled in the same direction. In response to the vehicle speed being less than a preset speed value, the steering of the front wheels and the steering of the rear wheels are controlled in opposite directions. A method used to control the steering angle of the front wheel and / or the steering angle of the rear wheel based on at least one of the front wheel tilt and the rear wheel tilt, A four-wheel steering electric vehicle.

2. The four-wheel steering electric vehicle according to claim 1, wherein the preset speed value is 25 kilometers per hour (km / hr) to 35 km / hr.

3. The four-wheel steering electric vehicle according to claim 1, wherein the four-wheel steering electric vehicle is an agricultural electric vehicle.

4. A rear wheel linkage mechanism connecting the rear wheel steering motor and the rear wheel, A rear wheel attitude detection unit is provided in the rear wheel linkage mechanism for detecting the rear wheel steering angle of the rear wheel linkage mechanism, A four-wheel steering electric vehicle according to claim 1, further comprising:

5. The control unit is electrically connected to the control unit and further includes a remote control signal receiving unit for receiving remote control signals, The four-wheel steering electric vehicle according to claim 1, wherein the control unit is further used to control at least one of the front wheel steering of the front wheels and the rear wheel steering of the rear wheels in accordance with the remote control signal.

6. A driving method for a four-wheel steering electric vehicle, applicable to any one of claims 1 to 5, wherein the driving method is: In response to the vehicle speed being greater than the preset speed value, the control unit controls the steering of the front wheels and the steering of the rear wheels in the same direction. In response to the vehicle speed being less than the preset speed value, the control unit controls the steering of the front wheels and the steering of the rear wheels in opposite directions. A driving method that includes the following.

7. The driving method according to claim 6, wherein the preset speed value is 25 km / hr to 35 km / hr.

8. The drive method according to claim 6, wherein the four-wheel steering electric vehicle is an agricultural electric vehicle.

9. The front wheel attitude detection unit detects the steering angle of the front wheel of the front wheel linkage mechanism. The rear wheel attitude detection unit detects the steering angle of the rear wheels of the rear wheel linkage mechanism. The driving method according to claim 6, further comprising the following:

10. The front wheel attitude detection unit detects the tilt of the front wheel in the front wheel linkage mechanism. The rear wheel attitude detection unit detects the degree of tilt of the rear wheel in the rear wheel linkage mechanism. The control unit controls the steering angle of the front wheel and / or the steering angle of the rear wheel based on at least one of the front wheel tilt and the rear wheel tilt. The driving method according to claim 6, further comprising the following:

11. The remote control signal receiving unit receives the remote control signal. The control unit controls at least one of the front wheel steering and the rear wheel steering in accordance with the remote control signal. The driving method according to claim 6, further comprising the following:

Images