Electric vehicle

Abstract

The purpose of the present invention is to provide an electric vehicle that can easily get rid of jamming during automatic driving. The electric vehicle according to the present invention is provided with a rotating electric machine for generating rotational driving force to each of a left drive wheel and a right drive wheel, and is capable of traveling in an automatic driving manner, and is provided with a control device for controlling the left drive wheel and / or the right drive wheel when it is determined that the left drive wheel and / or the right drive wheel is stuck while traveling in the automatic driving manner. And a driving force control unit that performs driving force control for clamping stagnation so as to raise and lower the torque generated by the rotating electric machine and rotationally drive the left driving wheel and the right driving wheel.

Description

TECHNICAL FIELD

[0001] The present application relates to an electric vehicle. BACKGROUND

[0002] In Patent Literature 1, a technology is disclosed in which, in an electric vehicle, a drive force is transmitted by elongating a suspension of a drive wheel on a slipping side and bringing it into contact with the ground.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2022-161380 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] When a stuck occurs during autonomous driving of an electric vehicle, the technology disclosed in Patent Literature 1 can not be able to escape from the stuck only by scraping the road surface.

[0008] The present application has been made in view of the above problems, and an object thereof is to provide an electric vehicle that can easily escape from a stuck during autonomous driving.

[0009] MEANS FOR SOLVING PROBLEMS

[0010] In order to solve the above problems and achieve the object, the electric vehicle of the present application is characterized by comprising a control device that, in a case where it is determined that a stuck has occurred in at least one of a left drive wheel and a right drive wheel during autonomous driving, executes a stuck drive force control that raises and lowers a torque generated by a rotary electric machine and rotates the left drive wheel and the right drive wheel.

[0011] Thus, in addition to the rotational drive forces of the left and right drive wheels, a reaction force is utilized, and it is possible to easily escape from a stuck during autonomous driving.

[0012] Further, in the above, as the rotary electric machine, there can be a left wheel-in-wheel motor provided to the left drive wheel and a right wheel-in-wheel motor provided to the right drive wheel, and the control device can cause the magnitudes of the torques generated by the left and right wheel-in-wheel motors to be different at the same timing by the stuck drive force control.

[0013] Thus, a sawing effect based on a difference in the rotational drive forces between the left and right drive wheels occurs, and it is possible to improve the stuck escape ability.

[0014] Effects of Invention

[0015] The electric vehicle of the present application has the effect that it can easily escape from a stuck state during automatic driving by using the reaction force in addition to the rotational driving force of the left and right drive wheels. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic diagram showing an example of the schematic structure of the electric vehicle of Embodiment 1.

[0017] Figure 2 is a block diagram showing an example of the schematic structure of the control system in the electric vehicle of Embodiment 1.

[0018] Figure 3 is a flowchart showing an example of the stuck state determination and driving force control by the control device during automatic driving of the electric vehicle of Embodiment 1.

[0019] Figure 4 is a timing chart regarding the driving force control for stuck in Embodiment 1.

[0020] Figure 5 is a graph showing the state of the drive wheels when the driving force control for stuck is executed.

[0021] Figure 6 is a flowchart showing an example of the stuck state determination and driving force control by the control device during automatic driving of the electric vehicle of Embodiment 2.

[0022] Figure 7 is a timing chart regarding the driving force control for stuck in Embodiment 2. DETAILED DESCRIPTION

[0023] (Embodiment 1)

[0024] Hereinafter, Embodiment 1 of the electric vehicle of the present application will be described. The present application is not limited to this embodiment.

[0025] Figure 1 is a schematic diagram showing an example of the schematic structure of the electric vehicle 1 of Embodiment 1. Figure 2 is a block diagram showing an example of the schematic structure of the control system in the electric vehicle 1 of Embodiment 1.

[0026] As Figure 1As shown, the electric vehicle 1 of Embodiment 1 is provided with a left front wheel 2FL, a right front wheel 2FR, a left rear wheel 2RL, and a right rear wheel 2RR. Among the left front wheel 2FL and the right front wheel 2FR, a left wheel motor 4FL and a right wheel motor 4FR are provided as in-wheel motors, respectively. The left front wheel 2FL and the right front wheel 2FR are drive wheels that are rotationally driven by the left wheel motor 4FL and the right wheel motor 4FR, respectively, and the left wheel motor 4FL and the right wheel motor 4FR are supplied with electric power from an on-vehicle battery or the like. The left front wheel 2FL, the right front wheel 2FR, the left rear wheel 2RL, and the right rear wheel 2RR are suspended to a vehicle body by a left front suspension 6FL, a right front suspension 6FR, a left rear suspension 6RL, and a right rear suspension 6RR, respectively. A control device 8 is capable of performing various controls related to travel of the electric vehicle 1. For example, the control device 8 controls the left wheel motor 4FL and the right wheel motor 4FR to rotationally drive the left front wheel 2FL and the right front wheel 2FR in response to depression of an accelerator pedal 14 (see FIG. 1) by a driver or a request for acceleration / deceleration from an automatic driving device 16. Thereby, the left front wheel 2FL and the right front wheel 2FR actuate a driving force with respect to a road surface, so that the electric vehicle 1 is able to move forward or backward. In the electric vehicle 1 of Embodiment 1, the control device 5 functions as a driving force control device. Figure 2

[0027] In addition, the in-wheel motors can be provided in all of the four wheels, or can be provided only in the left rear wheel 2RL and the right rear wheel 2RR. In addition, instead of the in-wheel motors, a configuration can be made to rotationally drive the left front wheel 2FL and the right front wheel 2FR by transmitting torque generated by a single rotary motor (motor generator) to the left front wheel 2FL and the right front wheel 2FR via a driving force transmission mechanism having a drive shaft or the like. In addition, a steering device (not shown) for controlling a steering angle of the wheels, and a braking device (not shown) for generating a braking force at each wheel are mounted on the electric vehicle 1. The steering device can employ a power steering device that doubles a rotational torque of a steering wheel (not shown) operated by the driver while transmitting a rotation of the steering wheel to tie rods (not shown), and steers the left front wheel 2FL and the right front wheel 2FR. The braking device can be any form of device that applies a braking force to each wheel 2FL, 2FR, 2RL, 2RR in response to depression of a brake pedal (not shown) by the driver.

[0028] The control device 8 inputs an operation amount or a depression amount of the accelerator pedal 14, wheel speeds Vwi (i = FL, FR, RL, RR) from the wheel speed sensors 12i (i = FL, FR, RL, RR) of each wheel 2FL, 2FR, 2RL, 2RR, and detection values from various sensors for detecting a state of the wheels and a motion state of the vehicle, and the like. In addition, the control device 8 can use GPS information from a GPS device 62 to detect a vehicle speed Vb. ​

[0029] Further, various parameters required for various controls performed in the electric vehicle 1, such as a depression amount of a brake pedal, a steering angle, a yaw rate, front and rear accelerations, and various detection signals such as lateral accelerations, can be input to the control device 8, and various control commands are output to corresponding devices. Then, for example, control signals Cfl, Cfr that adjust the torques generated by the left and right wheel motors 4FL, 4FR are transmitted from the control device 8 to the left and right wheel motors 4FL, 4FR.

[0030] The control device 8 has a calculation processing portion 80, a left drive wheel control portion 82, and a right drive wheel control portion 84. Further, the calculation processing portion 80 is provided with a torque determination portion 801 and a stuck determination portion 802. The torque determination portion 801 calculates and determines target values Twfl, Twfr of the torques generated by the left and right wheel motors 4FL, 4FR on the basis of a depression amount of the accelerator pedal 14 or a request for acceleration or deceleration from the automatic driving device 16. Then, the torque determination portion 801 outputs signals of the target values Twfl, Twfr of the torques generated by the left and right wheel motors 4FL, 4FR to the left and right drive wheel control portions 83, 84. The left and right drive wheel control portions 83, 84 output control signals Cfl, Cfr for generating torques corresponding to the received target values Twfl, Twfr of the torques to the left and right wheel motors 4FL, 4FR, respectively.

[0031] Further, as the automatic driving device 16, for example, a publicly known device that enables autonomous travel (automatic driving) of the electric vehicle 1 without dependence on accelerator operation or the like of a driver using a detection result of an external sensor such as a camera or the like can be used.

[0032] The stuck determination portion 802 of the calculation processing portion 80 determines, for example, whether at least one of the left and right front wheels 2FL, 2FR as drive wheels is stuck in a depression or the like to become a stuck state. The stuck determination portion 802 refers to, for example, wheel speeds VwFL, VwFR of the left and right front wheels 2FL, 2FR and a vehicle speed Vb determined from a temporal change in position information of the electric vehicle 1 obtained by the GPS device 10. Then, the stuck determination portion 802 determines that a stuck state is present on the basis of the wheel speeds VwFL, VwFR and the vehicle speed Vb in a case where the left and right front wheels 2FL, 2FR are rotating at a rotational speed of a prescribed rotational speed or higher but are standing still at substantially the same position at a vehicle speed of a prescribed vehicle speed or lower. For example, the stuck determination portion 802 can determine that a stuck state is present in a case where a difference between the wheel speed Vwi and the vehicle speed Vb is a prescribed threshold value or higher. Further, the stuck determination portion 802 can perform stuck determination on the basis of a detection result of a front and rear acceleration sensor provided to the electric vehicle 1.

[0033] In the electric vehicle 1 of Embodiment 1, when a stuck determination is made during automatic driving travel based on the automatic driving device 16, the drive force control of the control device 8 is switched from the normal drive force control to the drive force control for stuck. In the drive force control for stuck, the torque variation that causes the torque generated by the left wheel motor 4FL and the right wheel motor 4FR to be repeatedly raised and lowered is intentionally performed.

[0034] Figure 3 is a flowchart showing an example of the stuck determination and the drive force control by the control device 8 of the electric vehicle 1 of Embodiment 1 during automatic driving travel. Figure 4 is a timing chart related to the drive force control for stuck in Embodiment 1. Figure 5 is a graph showing the state of the drive wheel 2 when the drive force control for stuck is performed.

[0035] First, the control device 8 determines whether at least one of the left front wheel 2FL and the right front wheel 2FR is stuck during automatic driving travel of the electric vehicle 1 (Step S1). The control device 8 ends the series of controls in the case where it is determined that no stuck has occurred (No in Step S1). On the other hand, the control device 8 switches the drive force control of the left wheel motor 4FL and the right wheel motor 4FR from the normal drive force control to the drive force control for stuck in the case where it is determined that stuck has occurred (Yes in Step S1) (Step S2).

[0036] In the drive force control for stuck, as shown in Figure 4 , the control device 8 alternately switches the torque of the left wheel motor 4FL and the right wheel motor 4FR between 0 [Nm] and the torque Tw1 [Nm], causing the rotational drive force of the left front wheel 2FL and the right front wheel 2FR to be raised and lowered. Thereby, as shown in Figure 5 , the left front wheel 2FL and the right front wheel 2FR increase the motor torque from the state of being stuck in the depression 20 to the torque Tw1, and thereby, as shown by an arrow A in Figure 5 , the drive wheel 2 climbs up the front slope 202 from the bottom 201 of the depression 20. Then, the control device 8 decreases the motor torque from the torque Tw1 to 0, and thereby, as shown by an arrow B in Figure 5 , the drive wheel 2 rolls down from the front slope 202 to the bottom 201, and the drive wheel 2 climbs up the rear slope 203 due to the impact at that time. Then, the control device 8 again increases the motor torque to the torque Tw1, and thereby, on the rotational drive force acting on the drive wheel 2 by the torque Tw1 generated by the left wheel motor 4FL and the right wheel motor 4FR, the force acting on the drive wheel 2 due to the drive wheel 2 rolling down from the rear slope 203 toward the bottom 201, in other words, the inertia of the advancing electric vehicle 1 is added, and as shown by an arrow C in Figure 5 , the drive wheel 2 climbs up the front slope 202.

[0037] Next, the control device 8 executes the drive force control for the stuck while determining whether or not the left front wheel 2FL and the right front wheel 2FR have been released from the stuck (step S3). The control device 8 continues to execute the drive force control for the stuck while repeatedly executing the determination of step S3 until it is determined that the stuck has been released, in the case where it is determined that the stuck has not been released (NO in step S3). The control device 8 returns to the normal drive force control (step S4) in the case where it is determined that the stuck has been released (YES in step S3). Then, the control device 8 ends the series of controls.

[0038] As described above, in the electric vehicle 1 of Embodiment 1, the drive force control of the control device 8 is switched from the normal drive force control to the drive force control for the stuck in the case where the stuck determination is made during the automatic driving travel. Thereby, in the electric vehicle 1 of Embodiment 1, the left front wheel 2FL and the right front wheel 2FR can be easily released from the stuck during the automatic driving travel by the reaction force in addition to the rotational drive force.

[0039] In addition, in the electric vehicle 1 of Embodiment 1, as compared to the case where the left front wheel 2FL and the right front wheel 2FR are stuck during the automatic driving travel and are advanced by the rotational drive by the normal drive force control, the excessive scraping of the road surface can be suppressed, and the deterioration of the stuck can be suppressed. In addition, in the electric vehicle 1 of Embodiment 1, when the stuck occurs during the automatic driving travel, the left wheel motor 4FL and the right wheel motor 4FR do not rotate at a high rotational speed, and thus the load of the left wheel motor 4FL and the right wheel motor 4FR is reduced, and the adverse effect on the durability can be suppressed.

[0040] (Embodiment 2)

[0041] Hereinafter, Embodiment 2 of the electric vehicle of the present application will be described. In the electric vehicle 1 of Embodiment 2, as with the electric vehicle 1 of Embodiment 1 shown in FIG. 1, only the left wheel motor 4FL and the right wheel motor 4FR as the in-wheel motors are provided at the left front wheel 2FL and the right front wheel 2FR. In addition, in the electric vehicle 1 of Embodiment 2, the same description as the electric vehicle 1 of Embodiment 1 is appropriately omitted. Figure 1

[0042] Figure 6 is a flowchart showing an example of the stuck determination and the drive force control by the control device 8 of the electric vehicle 1 of Embodiment 2 during the automatic driving travel. Figure 7 is a timing chart related to the drive force control for the stuck in Embodiment 2.

[0043] ​First, the control device 8 determines whether at least one of the left front wheel 2FL and the right front wheel 2FR is stuck during the autonomous driving of the electric vehicle 1 (step S11). If the control device 8 determines that there is no sticking (no in step S11), the control device 8 terminates a series of controls. On the other hand, if the control device 8 determines that sticking has occurred (yes in step S11), the control device 8 switches the drive force control from normal drive force control to drive force control for sticking, which causes the magnitudes of the rotational drive forces of the left front wheel 2FL and the right front wheel 2FR at the same timing to be different (step S12).

[0044] In the drive force control for jamming in embodiment 2, such as Figure 7 As shown, the control device 8 alternately switches the torque of the right wheel motor 4FR to 0 and torque Tw2, causing the rotational driving force of the right front wheel 2FR to increase or decrease, and driving the right front wheel 2FR for a certain period of time. Similarly, it alternately switches the torque of the left wheel motor 4FL to 0 and torque Tw3 (>0), which is smaller than torque Tw2, causing the rotational driving force of the left front wheel 2FL to increase or decrease, and driving the left front wheel 2FL for a certain period of time. Furthermore, the timing of the increase and decrease of the torques of the right wheel motor 4FR and the left wheel motor 4FL are synchronized and set to the same time. Therefore, due to the difference in rotational driving force between the left front wheel 2FL and the right front wheel 2FR, the electric vehicle 1 can move forward while simultaneously moving to the left. Afterwards, the control device 8 alternately switches the torque of the right wheel motor 4FR to 0 and torque Tw3, causing the rotational driving force of the right front wheel 2FR to increase or decrease, and driving the right front wheel 2FR for a certain period of time. Furthermore, the control device 8 alternately switches the torque of the left wheel motor 4FL to 0 and torque Tw2, causing the rotational driving force of the left front wheel 2FL to increase or decrease, and driving the left front wheel 2FL for a certain period of time. Thus, due to the difference in rotational driving force between the left front wheel 2FL and the right front wheel 2FR, the electric vehicle 1 can move forward while simultaneously moving to the right. Then, at the same timing, the control device 8 causes the torque generated by the left wheel motor 4FL and the right wheel motor 4FR to differ in magnitude, and due to the difference in rotational driving force between the left front wheel 2FL and the right front wheel 2FL, alternately and repeatedly executes the driving force control for the electric vehicle 1 to move forward while simultaneously moving to the left, and the driving force control for the electric vehicle 1 to move forward while simultaneously moving to the right.

[0045] Next, the control device 8 executes the drive force control for the stuck while determining whether the left front wheel 2FL and the right front wheel 2FR are freed from the stuck (step S13). The control device 8 continues to execute the drive force control for the stuck while repeatedly executing the determination of step S13 until it is determined that the stuck is freed, in the case where it is determined that the stuck is not freed (NO in step S13). The control device 8 returns to the normal drive force control (step S14) in the case where it is determined that the stuck is freed (YES in step S13). Then, the control device 8 ends the series of controls.

[0046] As described above, in the electric vehicle 1 of Embodiment 2, in the case where the stuck determination is made during the automatic driving, the drive force control of the control device 8 is switched from the normal drive force control to the drive force control for the stuck which alternately changes the magnitudes of the rotational drive forces of the left front wheel 2FL and the right front wheel 2FR. Thereby, in the electric vehicle 1 of Embodiment 2, the sawing effect (lateral drive force) due to the difference between the rotational drive forces of the left front wheel 2FL and the right front wheel 2FR is generated, so that the left front wheel 2FL and the right front wheel 2FR are easily caught on the slope of the depression, and the stuck freeing ability can be improved.

[0047] Further, in the electric vehicle 1 of Embodiment 2, by implementing the drive force control for the stuck, the electric vehicle 1 does not need to be alternately steered left and right using the steering device when freed from the stuck, so that the durability of the steering device can be improved.

[0048] Explanation of Reference Numerals

[0049] 1 electric vehicle

[0050] 2FL left front wheel

[0051] 2FR right front wheel

[0052] 2RL left rear wheel

[0053] 2RR right rear wheel

[0054] 4FL left wheel motor

[0055] 4FR right wheel motor

[0056] 6FL left front suspension

[0057] 6FR right front suspension

[0058] 6RL left rear suspension

[0059] 6RR right rear suspension

[0060] 8 control device

[0061] 10 GPS device

[0062] 12i wheel speed sensor

[0063] 14 accelerator pedal

[0064] 16 autonomous driving device

[0065] 20 recess

[0066] 201 bottom

[0067] 202 front slope

[0068] 203 rear slope

Claims

1. An electric vehicle comprising a rotary motor that generates rotational driving force for a left drive wheel and a right drive wheel respectively, and capable of driving in an autonomous driving mode, characterized in that, The device includes a control unit that, upon determining that at least one of the left drive wheel and the right drive wheel has become stuck during autonomous driving, performs drive force control for the stuck wheel, which raises and lowers the torque generated by the rotary motor and drives the left drive wheel and the right drive wheel to rotate.

2. The electric vehicle according to claim 1, characterized in that, The rotary motor includes a left wheel in-wheel motor disposed on the left drive wheel and a right wheel in-wheel motor disposed on the right drive wheel. In the drive force control for jamming, the control device performs drive force control that makes the magnitudes of the torques generated by the left wheel in-wheel motor and the right wheel in-wheel motor different at the same timing.

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