Control method of electric vehicle, vehicle controller and electric vehicle

Abstract

The invention discloses a control method for reducing turning roll, a vehicle controller and an electric vehicle, relates to the field of new energy vehicles, and can be applied to pure electric vehicles and hybrid vehicles. The control method comprises the steps that the steering wheel angle of the electric vehicle is increased from zero at the first moment, the torque output by an active transverse stabilizer bar of the electric vehicle is controlled to be increased, and the difference value of the driving torque of a left wheel and the driving torque of a right wheel which are coaxial of the electric vehicle is controlled to be increased. And at a second moment after the first moment, the steering angle of the steering wheel of the electric vehicle is increased from being smaller than the preset steering angle to being equal to or larger than the preset steering angle, the torque output by the active transverse stabilizer bar is controlled to be reduced, and the difference value of the driving torque of the left wheel and the driving torque of the right wheel is controlled to be reduced. According to the scheme, the roll angle of the vehicle body in the turning process can be reduced, the vehicle body control capacity is improved, the system robustness is improved, and the driving experience and safety of the vehicle are improved.

Description

Technical Field

[0001] The present application relates to the field of new energy vehicles, and more specifically, to a control method for reducing turning roll, a vehicle controller and an electric vehicle. Background Art

[0002] During vehicle driving, excessive left-right shaking or swaying of the vehicle body will cause discomfort to the driver and passengers, and severe body roll, such as sharp turns at high speed, may trigger the vehicle to roll outward, causing casualties. When the vehicle passes a large turn at an intersection, there will be obvious body roll, and the body of the driver and passengers will roll with the body, affecting driving comfort and confidence. If a large turn is made at an intersection on a slippery road, the wheels are prone to slipping, causing the vehicle to swing. Large axle load transfer leads to loss of tire friction limit circle, especially lateral force loss, which affects steering control performance, increases the frequency of driver operation, reduces the limit lateral acceleration, and thus reduces the safety margin.

[0003] Existing lateral stabilizers usually include passive lateral stabilizers and active lateral stabilizers. However, passive lateral stabilizers cannot be actively adjusted, and the body roll problem cannot be optimized. Active lateral stabilizers are controlled according to the roll angle, but the body roll angle sensor sampling and estimation are difficult, the system control is not accurate, and the robustness is poor.

[0004] Therefore, how to reduce the body roll of an electric vehicle when it turns is a problem that needs to be solved. Summary of the invention

[0005] The present application provides a control method for reducing cornering roll, a vehicle controller and an electric vehicle, which coordinate yaw rate stability control through active lateral stabilizer bar control to reduce the roll angle of the vehicle body during cornering, greatly improve the vehicle body control capability, maximize the tire lateral force, provide directional stability capability, improve the system robustness, and improve the driving experience and safety of the vehicle.

[0006] In a first aspect, the present application provides a control method for an electric vehicle, which is used to control the electric vehicle to reduce the turning roll during the turning process of the electric vehicle. The control method includes increasing the steering wheel angle of the electric vehicle from zero at a first moment, controlling the torque output by the active lateral stabilizer bar of the electric vehicle to increase, and controlling the difference between the driving torque of a left wheel and a right wheel of the coaxial electric vehicle to increase. At a second moment after the first moment, the steering wheel angle of the electric vehicle increases from less than a preset angle to equal to or greater than a preset angle, controlling the torque output by the active lateral stabilizer bar to decrease, and controlling the difference between the driving torque of a left wheel and a right wheel to decrease.

[0007] The electric vehicle is a vehicle equipped with an active lateral stabilizer bar. The active lateral stabilizer bar includes an actuator and a stabilizer bar, and the actuator is used to output torque to the stabilizer bar to twist the stabilizer bar. The electric vehicle includes a plurality of drive motors, and the plurality of drive motors are used to drive a plurality of wheels respectively.

[0008] When an electric vehicle is turning, the vehicle will generate lateral acceleration, which will cause the vehicle body to roll around the roll axis of the electric vehicle, resulting in a height difference between the left and right sides of the vehicle body. Excessive left-right shaking or swaying of the vehicle body will cause discomfort to the driver and passengers, and obvious body roll will cause the driver and passengers to roll with the body, affecting driving comfort and driving confidence.

[0009] In a vehicle with a traditional passive anti-roll bar, the roll moment is borne by the passive anti-roll bar and the spring. The spring on the outside of the turn is compressed and the spring on the inside is stretched. The outer rocker arm of the passive anti-roll bar is pressed downward, and the generated torque is transmitted to the inner rocker arm, pulling the inner body downward, thereby reducing the outward tilt of the body.

[0010] Compared with the passive lateral stabilizer bar, the active roll control (ARC) has an actuator added, and the vehicle body posture can be adjusted through the active action control of the actuator. The actuator can be hydraulic or electric. The stabilizer bar can include one or more components. The active lateral stabilizer bar can generate real-time adjustable anti-roll torque through active action. For example, when the electric vehicle turns left, due to the centrifugal force, the body tilts to the outside (right side), and the actuator of the active lateral stabilizer bar outputs torque, so that the left and right sides of the stabilizer bar generate torques of equal magnitude and opposite directions, which jointly generate a counterclockwise anti-roll torque on the body, thereby reducing the roll of the body. The present application does not specifically limit the structural form, power source and installation method of the active lateral stabilizer bar.

[0011] It should be understood that the control of the active stabilizer bar can be performed by a motor controller, a vehicle controller or other separately arranged controllers with control capabilities. These controllers can be connected to the active stabilizer bar through a controller area network (CAN) bus, a local interconnect network (LIN) bus, a high-speed fault-tolerant network protocol (FlexRay) bus or other wired or wireless connection methods, and exchange signals.

[0012] The coaxial left wheel and right wheel in the present application are the left and right side wheels and the right rear wheel, and can also be the left front wheel and the right front wheel.

[0013] When the electric vehicle is driving, when the steering wheel angle of the electric vehicle increases and the electric vehicle turns, the electric vehicle will generate lateral acceleration. Lateral acceleration refers to the acceleration component of the electric vehicle in a direction perpendicular to the speed of the electric vehicle when turning, which can also be called lateral acceleration.

[0014] When an electric vehicle turns at a high speed or at a large angle, the centrifugal force will cause the vehicle body to roll, which will cause the vehicle's load to transfer. Large load transfer will cause the tire friction limit circle loss, especially the lateral force loss, affecting the steering control performance. At the same time, the adjustment of the roll angle by the active lateral stabilizer bar will change the tire vertical load, thereby indirectly affecting the vehicle's yaw stability.

[0015] The yaw acceleration is the acceleration of the electric vehicle's body rotating around the vertical axis during a turn. The yaw acceleration is affected by the speed and turning angle of the electric vehicle. When the speed increases, the yaw acceleration will increase accordingly because the vehicle needs to generate greater centrifugal force to overcome the inertia force during the turn. The yaw acceleration is generally proportional to the lateral acceleration. In order to ensure the lateral force of the tire and provide directional stability, the drive motor can generate torque vectoring for yaw control.

[0016] The yaw control may be performed by a motor controller or a vehicle controller. The motor controller may be applicable to an electric vehicle or a hybrid vehicle, the electric vehicle may be a distributed motor or a centralized motor architecture, having multiple drive motors and multiple motor controllers, the motor controller may be any one of the multiple motor controllers. The vehicle controller may send a torque signal to the multiple motor controllers, so that the motor controller controls the drive motor to output the torque indicated by the torque signal.

[0017] When the torque output by the drive motor for driving the left wheel is different from the torque output by the drive motor for driving the right wheel, the torque applied to the electric vehicle will generate lateral force. By adjusting the torque output by multiple drive motors, the difference between the torque output by the drive motor for driving the left wheel and the torque output by the drive motor for driving the right wheel can be controlled.

[0018] At the second moment, the steering wheel angle of the electric vehicle is stabilized during the turning process. At this time, the torque output by the actuator of the active lateral stabilizer bar reaches its peak value, and the difference between the driving torque of the left wheel and the driving torque of the right wheel also reaches its peak value. During the turning process of the vehicle, the roll angle will overshoot. The overshoot phenomenon refers to the roll angle change exceeding its final stable value, and then it will return and stabilize near its final value. It may cause discomfort to passengers and even affect the stability and safety of the vehicle. Roll angle overshoot usually occurs at the moment when the steering wheel angle is stable, that is, the second moment. Therefore, by adjusting the torque of the actuator of the lateral stabilizer bar and the yaw torque of the drive motor to reach the peak at the second moment, the overshoot of the roll angle can be effectively suppressed and the comfort of the driver and passengers can be improved.

[0019] According to the solution of the present application, the torque of the actuator of the active stabilizer bar is controlled in coordination with the drive motor to generate a torque vector for control, thereby reducing the roll angle of the vehicle body, maximizing the lateral force of the tire, providing directional stability, and improving the driving experience and safety of the vehicle.

[0020] In combination with the first aspect, in certain implementations of the first aspect, the control method further includes, at a third moment after the second moment, the steering wheel angle is less than the steering wheel angle at the second moment, controlling the active lateral stabilizer bar to output a reverse torque. At a fourth moment after the third moment, the steering wheel angle decreases to less than a second preset angle, controlling the active lateral stabilizer bar to reduce the reverse torque output.

[0021] When the active lateral stabilizer bar outputs a reverse torque, the torsion direction of the stabilizer bar of the active lateral stabilizer bar is different, that is, the torsion direction of the stabilizer bar is different when the actuator outputs a torque and outputs a reverse torque.

[0022] At the third moment, the steering wheel starts to return to the center position, and the roll angle of the electric vehicle starts to decrease. At the fourth moment, the steering wheel returns to the center position, and the roll angle overshoot phenomenon will also occur, causing discomfort to the driver and passengers. By controlling the active lateral stabilizer bar to output reverse torque from the third moment to slow down the change of the roll angle of the electric vehicle, at the fourth moment, the reverse torque output by the active lateral stabilizer bar reaches the peak value, which can effectively suppress the overshoot of the roll angle and improve the comfort of the driver and passengers.

[0023] After the fourth moment, after the steering wheel returns to the center position, the electric vehicle ends the turn and goes straight. At this time, the roll angle of the electric vehicle gradually decreases and approaches zero degrees. The torque output by the active lateral stabilizer bar is controlled to gradually decrease, so that the roll angle of the electric vehicle slowly decreases.

[0024] According to the solution of the present application, by controlling the size and direction of the output torque of the active lateral stabilizer bar, the overshoot of the roll angle is suppressed, the drastic change of the roll angle is reduced, and the driving experience and safety of the vehicle are improved.

[0025] In combination with the first aspect, in certain implementations of the first aspect, the control method further includes controlling the torque output by the active stabilizer bar to decrease to zero between the second moment and the third moment.

[0026] At the second moment, the steering wheel angle of the electric vehicle is stabilized during the turning process, and the steering wheel angle remains unchanged between the second moment and the third moment. If the active lateral stabilizer bar continues to increase or maintain a large torque output, the roll angle of the electric vehicle will remain unchanged or decrease. Since the electric vehicle is still in the process of turning, if the driver cannot feel the change in the roll angle during a large turning angle, it will lead to a lack of control over the turning feeling, affecting the operating experience, which may cause the driver to continue to increase the turning angle, causing damage to the hardware of the electric vehicle. Therefore, the vehicle controller controls the torque output by the active lateral stabilizer bar to gradually decrease. At this time, the roll angle of the electric vehicle 10 increases slowly, and the roll angle and lateral acceleration increase in a preset relationship. The roll angle change is not excessively suppressed, so that the driver has a proper operating experience, and excessive suppression is avoided to affect vehicle safety, so that the driver and passengers feel comfortable, thereby improving the comfort of the vehicle.

[0027] According to the solution of the present application, by controlling the torque output of the active lateral stabilizer bar to be reduced, the drastic change of the roll angle is reduced while providing a driving feel, thereby improving the driving experience and safety of the vehicle.

[0028] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes controlling the torque output by an active stabilizer bar of the electric vehicle to increase as the height difference between a left wheel and a right wheel increases between a first moment and a second moment.

[0029] It should be understood that the height difference between a left wheel and a right wheel of an electric vehicle in the present application refers to the difference between the distance between the body of the electric vehicle and the left wheel and the distance between the body and the right wheel, or the difference between the distance between the body of the electric vehicle and the ground at the left wheel and the distance between the body of the electric vehicle and the ground at the right wheel. The difference can be detected by a height sensor of the electric vehicle, which can be installed on the suspension system or the body to monitor the height difference between the tire and the body in real time.

[0030] When the roll angle of an electric vehicle changes, the height difference between the vehicle body and the left and right wheels will change. Therefore, the roll angle of the electric vehicle at this time can be obtained by the height difference between a left wheel and a right wheel indicated by the height sensor. Since it is difficult for the roll angle sensor of an electric vehicle to directly sample and estimate the roll angle, the control of the active lateral stabilizer bar based on the signal of the roll angle sensor has the problem of inaccurate system control and poor robustness. The difference between the height of the left wheel and the height of the right wheel indicated by the height sensor can more accurately and quickly obtain the change in the roll angle of the electric vehicle.

[0031] According to the solution of the present application, closed-loop control is performed using wheel height difference, and the active lateral stabilizer bar output torque is controlled in coordination with the drive motor to generate a torque vector for control, thereby reducing the roll angle of the vehicle body, maximizing the lateral force of the tire, providing directional stability, improving the robustness of the system, and improving the driving experience and safety of the vehicle.

[0032] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes controlling the difference between the driving torque of a left wheel and the driving torque of a right wheel to increase as the steering wheel angle increases between the first moment and the second moment.

[0033] The motor controller or vehicle controller can determine the yaw torque required for the electric vehicle to turn according to the steering wheel command and the body posture information of the electric vehicle, so as to adjust the difference between the driving torque for a left wheel and the driving torque for a right wheel according to the required yaw torque. The motor controller or vehicle controller outputs the target yaw angular velocity through the steering wheel command, and performs closed-loop control with the actual yaw angular velocity of the vehicle to output the vehicle yaw torque.

[0034] According to the solution of the present application, the difference between the driving torque of the left wheel and the driving torque of the right wheel is adjusted according to the command of the steering wheel, so as to effectively control the yaw of the vehicle and suppress the roll angle, thereby improving the driving experience and safety of the vehicle.

[0035] In combination with the first aspect, in certain implementations of the first aspect, the control method also includes between the second moment and the third moment, the steering wheel angle remains unchanged, and the difference between the driving torque of a left wheel and the driving torque of a right wheel is controlled to be reduced to zero.

[0036] At the second moment, the steering wheel angle is stabilized during the turning process of the electric vehicle. At this time, the torque output by the active anti-roll bar reaches its peak value. Therefore, by adjusting the yaw torque of the drive motor to reach its peak value at the second moment, the overshoot of the roll angle can be effectively suppressed. Between the second moment and the third moment, the steering wheel angle remains unchanged, and the yaw torque required for the electric vehicle to turn gradually decreases. Therefore, the difference between the driving torque of a left wheel and the driving torque of a right wheel is reduced to zero.

[0037] According to the solution of the present application, the torque vector is generated by controlling the drive motor to control the lateral force of the tire while suppressing the yaw, thereby improving the driving experience and safety of the vehicle.

[0038] In combination with the first aspect, in some implementations of the first aspect, the control method specifically includes, at a first moment, the steering wheel angle of the electric vehicle to the left increases from zero, and the driving torque of a left wheel is controlled to be less than the driving torque of a right wheel. At a first moment, the steering wheel angle of the electric vehicle to the right increases from zero, and the driving torque of a left wheel is controlled to be greater than the driving torque of a right wheel.

[0039] When the electric vehicle turns left, the driving torque of the left wheel of the electric vehicle is controlled to be smaller than the driving torque of the right wheel. When the electric vehicle turns right, the driving torque of the left wheel of the electric vehicle is controlled to be larger than the driving torque of the right wheel, thereby generating a vector torque to suppress the vehicle's yaw.

[0040] According to the solution of the present application, the torque vector is generated by controlling the driving motor. When turning in different directions, the driving torques on the left and right sides are controlled to be different. While ensuring the lateral force of the tire, the yaw is suppressed to improve the driving experience and safety of the vehicle.

[0041] In combination with the first aspect, in certain implementations of the first aspect, the control method further includes controlling the driving torque of any wheel to decrease in response to an increase in the slip rate of any wheel during a turning process of the electric vehicle.

[0042] If you make a sharp turn on a slippery road, the wheels will slip more easily due to the lower friction and load transfer of the electric vehicle. The vehicle will then skid and vibrate, making it difficult for the driver to control, which can easily lead to safety accidents.

[0043] When an electric vehicle starts to turn, the adhesion of the tire fluctuates in real time due to the change in road adhesion. When the adhesion of the tire changes, the slip rate of the tire will also change. Therefore, when the slip rate of one wheel of the electric vehicle increases, the electric vehicle may slip and need to be controlled.

[0044] It should be understood that when the adhesion between the wheel and the road changes, the speed and torque of the drive motor used to drive the wheel will also change. Therefore, the motor controller can sense the changes in the road adhesion through the changes in the speed of the drive motor detected by the resolver sensor, so that the motor controller can actively adjust the actual output torque of the drive motor according to the resolver signal of the drive motor, thereby accurately controlling the slip rate of the tire.

[0045] According to the solution of the present application, on the basis of active lateral stabilizer bar control, a short detection cycle of a resolver sensor near the drive motor is used to observe slip and rotation, perform closed-loop torque adjustment, and achieve rapid control of the slip rate, thereby solving the problems of large turn slipping and body sway from the longitudinal and vertical integration.

[0046] In combination with the first aspect, in certain implementations of the first aspect, the control method also includes controlling the driving torque of a left wheel and the driving torque of a right wheel to decrease and controlling the difference between the driving torque of a left wheel and the driving torque of a right wheel to increase between the first moment and the second moment.

[0047] Between the first moment and the second moment, the steering wheel angle is large, the electric vehicle turns to one side, the yaw rate and lateral acceleration both increase, and due to the increase in the roll angle, the tire lateral force changes, and the electric vehicle may slip. Therefore, it is necessary to control the yaw moment while adding the control of the slip rate to ensure the coordinated stability of the longitudinal and lateral control. In order to suppress the roll angle and yaw, it is necessary to control the difference between the driving torque of a left wheel and the driving torque of a right wheel to increase, and at the same time, in order to suppress slip, it is necessary to reduce the driving torque.

[0048] According to the solution of the present application, on the basis of the lateral stabilizer bar control and the proximal end slip closed-loop control of the drive motor, the drive system is coordinated to utilize the electric drive to generate a torque vector for feedforward control. By adjusting the longitudinal force, the lateral force of the tire is guaranteed to the greatest extent and directional stability is provided.

[0049] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: when the lateral acceleration of the electric vehicle is less than an acceleration threshold, controlling the torque output by the active lateral stabilizer bar of the electric vehicle to increase as the height difference between a left wheel and a right wheel increases. When the lateral acceleration of the electric vehicle is greater than or equal to the acceleration threshold, controlling the active lateral stabilizer bar of the electric vehicle to adjust the output torque so that the height difference between a left wheel and a right wheel reaches a preset value, and the preset value increases as the lateral acceleration of the electric vehicle increases.

[0050] When the speed of the electric vehicle is low or the steering wheel angle is small, the lateral acceleration generated by the electric vehicle is small, and the control target of the roll angle of the electric vehicle should be to suppress the roll angle of the electric vehicle as much as possible, so that the driver and passengers feel safe and improve the comfort of the vehicle. Therefore, when the lateral acceleration is less than the acceleration threshold, the active lateral stabilizer bar is controlled to increase the output torque, and the torque output by the active lateral stabilizer bar increases with the increase of the difference between the height of the left wheel and the height of the right wheel, so that the torque output by the active lateral stabilizer bar increases with the increase of the roll angle of the electric vehicle, thereby increasing the anti-roll torque generated by the active lateral stabilizer bar to reduce the roll angle of the electric vehicle.

[0051] When the speed of the electric vehicle is high or the steering wheel angle is large, the lateral acceleration generated by the electric vehicle is large. The control target of the roll angle of the electric vehicle should be that the roll angle increases linearly with the lateral acceleration, so as not to over-suppress the change of the roll angle, so that the driver has a proper operating experience, avoid excessive suppression affecting vehicle safety, make the driver and passengers feel comfortable, and improve the comfort of the vehicle. Therefore, when the lateral acceleration is greater than or equal to the acceleration threshold, the active lateral stabilizer bar is controlled to adjust the output torque, and the torque output by the active lateral stabilizer bar controls the roll angle of the electric vehicle to increase with the increase of the lateral acceleration, so that the anti-roll torque generated by the active lateral stabilizer bar increases to adjust the rate of change of the roll angle of the electric vehicle. The corresponding relationship between the preset value and the lateral acceleration can be preset.

[0052] According to the solution of the present application, lateral acceleration feedforward is adopted, and closed-loop control is performed in conjunction with the wheel height difference to control the output torque of the active lateral stabilizer bar to reduce the roll angle of the vehicle body, thereby avoiding inaccurate control caused by difficulties in measuring and estimating the roll angle of the vehicle body, improving the robustness of the system, and improving the driving experience and safety of the vehicle.

[0053] In a second aspect, the present application provides a vehicle controller for body control of an electric vehicle when turning, the electric vehicle including an active lateral stabilizer bar. The vehicle controller is used to control the torque output by the active lateral stabilizer bar to increase with the increase of the height difference between a coaxial left wheel and a coaxial right wheel of the electric vehicle during the driving process of the electric vehicle when the steering wheel angle of the electric vehicle increases and when the lateral acceleration of the electric vehicle is less than an acceleration threshold. The difference between the driving torque of a left wheel and the driving torque of a right wheel is controlled to increase with the increase of the steering wheel angle. When the lateral acceleration of the electric vehicle is greater than or equal to the acceleration threshold, the active lateral stabilizer bar is controlled to adjust the output torque so that the height difference between a coaxial left wheel and a coaxial right wheel of the electric vehicle reaches a preset value.

[0054] The vehicle controller may be a vehicle controller or a motor controller of an electric vehicle or a separately provided controller with control capabilities.

[0055] In combination with the second aspect, in certain implementations of the second aspect, the vehicle controller is also used to control the torque output by the active stabilizer bar to decrease and control the difference between the driving torque of a left wheel and the driving torque of a right wheel to decrease when the steering wheel angle of the electric vehicle increases to be equal to or greater than a preset angle.

[0056] In combination with the second aspect, in certain implementations of the second aspect, the vehicle controller is further configured to control the active lateral stabilizer bar to output a reverse torque when the steering wheel angle of the electric vehicle decreases. When the steering wheel angle of the electric vehicle decreases to less than a second preset angle, the active lateral stabilizer bar is controlled to reduce the reverse torque output. The difference between the driving torque of a left wheel and the driving torque of a right wheel is controlled to decrease to zero.

[0057] In combination with the second aspect, in certain implementations of the second aspect, the vehicle controller is further configured to control the driving torque of any wheel to decrease in response to an increase in the slip rate of any wheel during a turning process of the electric vehicle.

[0058] In a third aspect, the present application provides an electric vehicle, comprising a vehicle controller and an active stabilizer bar, wherein the vehicle controller is used to execute the method described in the first aspect and its various implementations, and the active stabilizer bar comprises an actuator and a stabilizer bar, wherein the actuator is used to output torque to the stabilizer bar to twist the stabilizer bar.

[0059] The beneficial effects of other aspects can refer to the beneficial effects described in the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is a schematic diagram of an electric vehicle turning provided by an embodiment of the present application;

[0061] Figure 2 is a schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0062] Figure 3 is a schematic diagram of the architecture of an electric vehicle provided in an embodiment of the present application;

[0063] Figure 4 is a schematic diagram of a turning vehicle body roll angle control process provided by an embodiment of the present application;

[0064] Figure 5 is a schematic diagram of a cornering vehicle body roll angle control architecture provided in an embodiment of the present application;

[0065] Figure 6 is a schematic diagram of the vehicle body collaborative control process provided by an embodiment of the present application;

[0066] Figure 7 It is a schematic diagram of the vehicle body collaborative control result provided in an embodiment of the present application. DETAILED DESCRIPTION

[0067] The following will describe the technical solution in the present application in conjunction with the accompanying drawings. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0068] The safety of vehicle driving depends largely on the control of rolling motion. Figure 1 As shown in (a), when making a wide turn at an intersection on a slippery road, the vehicle body will Figure 1 In (b), the vehicle body rolls significantly, and the body of the driver and passengers rolls with the vehicle body, affecting driving comfort and confidence. In the case of large turns, the large axle load transfer leads to the loss of the tire friction limit circle, especially the lateral force loss, which affects the steering control performance, increases the frequency of driver operation, and reduces the limit lateral acceleration. Figure 1 As shown in (c), the loss of lateral force can easily cause the wheels to slip, resulting in the vehicle skidding and shimmying, making it difficult for the driver to control the vehicle, which can easily lead to safety accidents.

[0069] In a possible implementation, a passive lateral stabilizer bar is provided to control the roll angle of the vehicle body when turning.

[0070] It should be understood that the passive lateral stabilizer bar cannot be actively adjusted, and the body roll problem cannot be further optimized. When the undulations on the road impact the wheels and body on one side, the torque generated by the passive lateral stabilizer bar will be transmitted to the wheels and body on the other side, causing discomfort to the driver and passengers.

[0071] Based on the above problems, the present application provides a control method for reducing cornering roll. The vehicle controller and the electric vehicle coordinate the yaw rate stability control through active lateral stabilizer bar control to reduce the roll angle of the vehicle body during cornering, greatly improve the body control ability, maximize the tire lateral force, provide directional stability, improve the system robustness, and improve the driving experience and safety of the vehicle.

[0072] Figure 2 and Figure 3 It is a schematic diagram of the architecture of the electric vehicle 10 provided in an embodiment of the present application.

[0073] like Figure 2 As shown, the electric vehicle 10 includes a vehicle controller 20, a motor controller 40, a power battery (not shown) and a plurality of wheels. The motor controller 40 is used to output current to the drive motor to control the drive motor to output torque to drive the electric vehicle 10.

[0074] The vehicle controller in the present application may be the motor controller 40 of the electric vehicle 10, or the vehicle controller 20, or a separately provided controller with control capabilities.

[0075] It is understandable that the electric vehicle 10 in the embodiment of the present application can be any one of different types of vehicles such as a car, a truck, a passenger bus, etc., and can also be a transport device for carrying people or goods such as a tricycle, a two-wheeled vehicle, a train, or other types of vehicles driven by power batteries, which are not limited in the embodiment of the present application. Among them, vehicles include but are not limited to pure electric vehicles (pure electric vehicle / battery electric vehicle, pure EV / battery EV), hybrid electric vehicles (hybrid electric vehicle, HEV), range extended electric vehicles (range extended electric vehicle, REEV), plug-in hybrid electric vehicles (plug-in hybrid electric vehicle, PHEV), new energy vehicles (new energy vehicle, NEV), etc.

[0076] It is understandable that the power battery in the embodiment of the present application can be a lithium-ion battery, a lithium metal battery, a lead-acid battery, a nickel-cadmium battery, a nickel-hydrogen battery, a lithium-sulfur battery, a lithium-air battery or a sodium-ion battery, etc., and the present application does not limit this. In terms of scale, the power battery in the embodiment of the present application can be a single cell, or a battery module or a battery pack. The power battery can also power other electrical devices in the vehicle, such as the air conditioner in the vehicle, the car player, etc.

[0077] The electric vehicle 10 may be a wheel-side four-drive motor drive architecture, where the drive motor is arranged on the side of the driven wheel and controlled by a separate motor controller 40. The electric vehicle may also be a centralized drive motor drive architecture, where two drive motors for driving two front wheels or two rear wheels are arranged together. The motor controller 40 may be one or more. The motor controller 40 and the drive motor may correspond one to one, or one motor controller 40 may correspond to multiple drive motors. The motor controller 40 is used to control the output torque of one or more drive motors to drive the electric vehicle 10.

[0078] In one embodiment, if Figure 3 As shown in (a) of FIG. 1 , the electric vehicle 10 may be a wheel-side four-drive motor drive architecture, where the drive motor is arranged on the side of the driven wheel and is controlled by a separate motor controller. The electric vehicle 10 may also be a Figure 3In the centralized four-motor drive architecture shown in (b), two drive motors for driving two front wheels or two rear wheels are arranged together.

[0079] Exemplarily, the electric vehicle 10 includes four motor controllers, including a motor controller 41, a motor controller 42, a motor controller 43, and a motor controller 44. The four motors include a drive motor 51, a drive motor 52, a drive motor 53, and a drive motor 54. The motor controller 41 controls the drive motor 51 to drive one wheel, the motor controller 42 controls the drive motor 52 to drive one wheel, the motor controller 43 controls the drive motor 53 to drive one wheel, and the motor controller 44 controls the drive motor 54 to drive one wheel.

[0080] In one embodiment, the electric vehicle 10 may also be Figure 3 As shown in (c) of the figure, one driving motor is used to drive the two front wheels of the electric vehicle 10, and two driving motors are used to drive the two rear wheels of the electric vehicle 10 respectively.

[0081] In one embodiment, the various architectures mentioned above may be combined, for example, the front drive adopts a wheel-side drive motor architecture and the rear drive adopts a centralized drive motor architecture.

[0082] The vehicle controller provided in the implementation of the present application may be any one of a plurality of motor controllers.

[0083] The electric vehicle 10 further includes an accelerator pedal and a steering wheel. The accelerator pedal is used to indicate the torque output to the wheels of the electric vehicle 10.

[0084] In one embodiment, the motor controller 40 includes a signal interface, and the motor controller 40 is connected to the vehicle controller 20 and other motor controllers 40 through the signal interface. The vehicle controller 20 is connected to the accelerator pedal signal, and the vehicle controller 20 calculates the vehicle torque demand according to the opening of the accelerator pedal during the driving of the electric vehicle 10, and sends a torque signal to the motor controller 40 according to the vehicle torque demand. Each motor controller 40 controls the corresponding drive motor to output torque to drive the corresponding wheel according to the indication of the torque signal.

[0085] In one embodiment, each motor controller 40 may also be directly connected to the accelerator pedal, and control the corresponding motor output torque according to the torque signal output by the accelerator pedal.

[0086] The electric vehicle 10 also includes an active stabilizer bar 30 .

[0087] There can be one or more active lateral stabilizer bars 30. Figure 2An active lateral stabilizer bar 30 is installed on each of the front and rear axles. The active lateral stabilizer bar 30 includes an actuator 31 and a stabilizer bar, and the actuator 31 is used to output torque to the stabilizer bar to twist the stabilizer bar. Compared with the passive lateral stabilizer bar, the active lateral stabilizer bar 30 has an additional actuator 31, and the vehicle body posture can be adjusted by actively controlling the output torque of the actuator 31. The actuator 31 can be hydraulic or electric. The stabilizer bar can include one or more components. The active lateral stabilizer bar 30 can generate a real-time adjustable anti-roll moment through active actuation. For example, when the electric vehicle turns left, due to centrifugal force, the vehicle body tilts outward (right side), and the actuator 31 of the active lateral stabilizer bar 30 outputs torque, so that the left and right sides of the stabilizer bar generate torques of equal magnitude and opposite directions, and jointly generate a counterclockwise anti-roll moment on the vehicle body, thereby reducing the roll of the vehicle body. This application does not specifically limit the structural form, power source and installation method of the active lateral stabilizer bar.

[0088] In one embodiment, the motor controller 40 can be connected to the sensor, the vehicle controller 20 and the active anti-roll bar 30 through a controller area network (CAN) bus, a local interconnect network (LIN) bus, a high-speed fault-tolerant network protocol (FlexRay) or other types of connection methods, and interact with signals.

[0089] In order to facilitate understanding of the control method and vehicle controller for reducing turning roll provided in the embodiment of the present application, the following is combined with Figure 4 The control method for reducing turning roll and the vehicle controller provided by the embodiment of the present application are described at the first moment t1, the second moment t2, the third moment t3 and the fourth moment t4 during the turning process of the electric vehicle.

[0090] It should be understood that the vehicle controller provided in the present application may be a vehicle controller 20, a motor controller 40, or other separately configured controller with control capabilities.

[0091] like Figure 4 As shown, at the first moment t1, the steering wheel angle of the electric vehicle 10 increases from zero, and the vehicle controller is used to control the torque output by the active anti-roll bar 30 of the electric vehicle 10 to increase and control the difference between the driving torque of a left wheel and a right wheel of the coaxial electric vehicle 10 to increase.

[0092] At the first moment t1, the driver starts to turn the steering wheel, the steering wheel angle increases, and the electric vehicle 10 starts to turn, and the body of the vehicle rolls. When the electric vehicle 10 turns at a high speed or a large angle, the centrifugal force caused by the turn will cause the body of the vehicle to roll, which will cause the load transfer of the electric vehicle 10. A large load transfer will cause the tire friction limit circle loss, especially the lateral force loss, affecting the steering control performance. The vehicle controller can effectively reduce the roll angle of the vehicle by controlling the active lateral stabilizer bar 30 to increase the output torque.

[0093] When the active lateral stabilizer bar 30 outputs torque to adjust the roll angle, it will change the vertical load of the tire, thereby indirectly affecting the yaw stability of the vehicle. The yaw acceleration is the acceleration of the body of the electric vehicle 10 rotating around the vertical axis during the turning process. The yaw acceleration is affected by the speed and turning angle of the electric vehicle 10. When the speed increases, the yaw acceleration will increase accordingly because the vehicle needs to generate greater centrifugal force during the turning process to overcome the inertia force during the turning process. The yaw acceleration is generally proportional to the lateral acceleration.

[0094] In order to ensure the lateral force of the tire and provide directional stability, the vehicle controller can generate torque vectors by controlling one or more drive motors to perform yaw control. When the driving torque of a left wheel and a right wheel on the same axis are different, the electric vehicle 10 will generate lateral force when subjected to unequal left and right driving torques, thereby affecting the yaw angular velocity. Therefore, the vehicle controller can control the difference between the driving torque of a left wheel and the driving torque of a right wheel by adjusting the torque output by one or more drive motors.

[0095] When the electric vehicle 10 starts to turn, the roll angle starts to increase and the vehicle yaws at the same time. The vehicle controller increases the difference between the output torque and the left and right drive torques by cooperatively controlling the active anti-roll bar 30, thereby suppressing the roll angle and performing yaw stability control at the same time, thereby reducing the roll angle at the beginning of the turning process and improving yaw stability.

[0096] In one embodiment, the control method includes: at a first moment t1, the leftward turning angle of the steering wheel of the electric vehicle 10 increases from zero, and the vehicle controller controls the driving torque of a left wheel to be less than the driving torque of a right wheel. At a first moment t1, the rightward turning angle of the steering wheel of the electric vehicle 10 increases from zero, and the vehicle controller controls the driving torque of a left wheel to be greater than the driving torque of a right wheel.

[0097] When the electric vehicle 10 turns left, the vehicle controller controls the driving torque of the left wheel of the electric vehicle 10 to be smaller than the driving torque of the right wheel. When the electric vehicle turns right, the vehicle controller controls the driving torque of the left wheel of the electric vehicle 10 to be larger than the driving torque of the right wheel, thereby generating a vector torque to control the yaw stability of the vehicle.

[0098] In one embodiment, the control method specifically includes: between the first moment t1 and the second moment t2, the vehicle controller is used to control the torque output by the active anti-roll bar 30 of the electric vehicle 10 to increase as the height difference between a left wheel and a right wheel increases.

[0099] Between the first moment t1 and the second moment t2, the steering wheel angle increases, the roll angle of the electric vehicle 10 changes, and the height difference between the vehicle body and the left and right tires also changes. Therefore, the roll angle of the electric vehicle 10 can be obtained by the height difference between the left wheel and the right wheel indicated by the height sensor.

[0100] Since it is difficult for the roll angle sensor of the electric vehicle 10 to directly sample and estimate the roll angle, the control of the active lateral stabilizer bar 30 based on the signal of the roll angle sensor has the problem of inaccurate control and poor robustness. However, the difference between the height of the left wheel and the height of the right wheel indicated by the height sensor can more accurately and quickly obtain the change of the roll angle of the electric vehicle 10.

[0101] According to the solution of the present application, closed-loop control is performed using wheel height difference, and the active lateral stabilizer bar 30 outputs torque to coordinate with the drive motor to generate a torque vector for control, thereby reducing the roll angle of the vehicle body, maximizing the lateral force of the tire, providing directional stability, improving system robustness, and improving the driving experience and safety of the vehicle.

[0102] In one embodiment, the control method specifically includes: between a first moment t1 and a second moment t2, a vehicle controller is used to control a difference between a driving torque of a left wheel and a driving torque of a right wheel to increase as a steering wheel angle increases.

[0103] The vehicle controller can determine the yaw moment required for the electric vehicle 10 to turn according to the steering wheel command and the body posture information of the electric vehicle 10, so that the difference between the driving torque for a left wheel and the driving torque for a right wheel can be adjusted according to the required yaw moment. The motor controller or the vehicle controller outputs the target yaw angular velocity through the steering wheel command, and performs closed-loop control with the actual yaw angular velocity of the vehicle to output the vehicle yaw moment. Between the first moment t1 and the second moment t2, the steering wheel angle increases, and the yaw moment required for the electric vehicle 10 to turn is also greater. Therefore, the difference in the driving torque of the left and right wheels controlled by the vehicle controller increases with the increase of the steering wheel angle.

[0104] In one embodiment, the control method further includes: in response to an increase in the slip rate of any wheel during the turning process of the electric vehicle 10 , the vehicle controller is configured to control the driving torque of any wheel to decrease.

[0105] If a sharp turn is made on a slippery road, the wheels will slip more easily due to the lower friction and load transfer of the electric vehicle 10. If slip control is not applied at this time, the electric vehicle 10 will swing and flutter, making it difficult for the driver to control and easily causing a safety accident.

[0106] Starting from the first moment t1, when the electric vehicle 10 starts to turn, due to the change in road adhesion, the adhesion of the tires of the electric vehicle 10 fluctuates in real time. When the adhesion of the road changes, the slip rate of the tires will also change. Therefore, when the slip rate of one wheel of the electric vehicle 10 increases, the electric vehicle 10 may slip, and slip control is required. The vehicle controller needs to control the driving torque of the one wheel to reduce, thereby reducing the slip rate of the one wheel and avoiding slipping. Since the road surface-tire slips, the wheel speed increases, and the speed of the drive motor increases, so the longitudinal torque of the drive motor is controlled to decrease to suppress tire slip.

[0107] It should be understood that when the adhesion between the wheel and the road changes, the speed and torque of the drive motor used to drive the wheel will also change. Therefore, the vehicle controller can sense and observe the changes in road adhesion through the change in the speed of the drive motor detected by the resolver sensor. The vehicle controller can actively adjust the torque actually output by the drive motor according to the resolver signal of the drive motor, thereby accurately controlling the slip rate of the tire and preventing the electric vehicle 10 from slipping.

[0108] In one embodiment, the control method also includes: between the first moment t1 and the second moment t2, the vehicle controller is used to control the driving torque of a left wheel and the driving torque of a right wheel to decrease and control the difference between the driving torque of a left wheel and the driving torque of a right wheel to increase.

[0109] See again Figure 4 The change of the longitudinal torque and yaw torque of the vehicle, between the first moment t1 and the second moment t2, the steering wheel angle is large, the electric vehicle 10 turns to one side, the yaw angular velocity and the lateral acceleration both increase, and due to the increase of the roll angle, the lateral force of the tire changes, the electric vehicle 10 may slip, and the slip rate of the wheels of the electric vehicle increases. Therefore, it is necessary to control the slip rate while controlling the yaw torque to ensure the coordinated stability of the longitudinal and lateral control. In order to suppress the roll angle and yaw, it is necessary to control the difference between the driving torque of a left wheel and the driving torque of a right wheel to increase, and at the same time, in order to suppress slip, it is necessary to reduce the longitudinal driving torque of the electric vehicle 10.

[0110] Continue to see Figure 4 At a second moment t2 after the first moment t1, the steering wheel angle of the electric vehicle 10 increases from less than a preset angle to equal to or greater than a preset angle, the torque output by the active stabilizer bar 30 is controlled to decrease and the difference between the driving torque of a left wheel and the driving torque of a right wheel is controlled to decrease.

[0111] At the second moment t2, during the turning process of the electric vehicle 10, the driver's steering wheel angle is stabilized. At this time, the torque output by the active lateral stabilizer bar 30 reaches a peak value, and the difference between the driving torque of the left wheel and the driving torque of the right wheel also reaches a peak value. During the turning process of the electric vehicle 10, the roll angle will overshoot, and the roll angle change will exceed its final stable value, and then it will return to and stabilize near its final value. This roll angle overshoot phenomenon may cause discomfort to the driver and passengers and affect the stability and safety of the vehicle. Roll angle overshoot usually occurs at the moment when the steering wheel angle increases or decreases to a stable state, such as the second moment t2. Therefore, the vehicle controller can effectively suppress the overshoot of the roll angle and improve the comfort of the driver and passengers by adjusting the torque output by the lateral stabilizer bar 30 and the yaw torque of the left and right drive motors to reach a peak at the second moment.

[0112] In one embodiment, the control method further includes: between the second time t2 and the third time t3, the vehicle controller is used to control the torque output by the active stabilizer bar 30 to decrease to zero.

[0113] At the second moment t2, the steering wheel angle of the electric vehicle 10 is stabilized during the turning process, and the steering wheel angle remains unchanged between the second moment t2 and the third moment t3. If the vehicle controller controls the active lateral stabilizer bar 30 to continue to increase or maintain a large torque output, the roll angle of the electric vehicle 10 will remain unchanged or decrease. Since the electric vehicle 10 is still in the turning process, if the driver cannot feel the change in the roll angle during a large turning angle, it will lead to a lack of control over the turning feeling, affecting the operating experience, which may cause the driver to continue to increase the turning angle, causing damage to the hardware of the electric vehicle 10. Therefore, the vehicle controller controls the torque output by the active lateral stabilizer bar 30 to gradually decrease. At this time, the roll angle of the electric vehicle 10 increases slowly, and the roll angle increases with the lateral acceleration in a preset relationship. The roll angle change is not excessively suppressed, so that the driver has a proper operating experience, and the excessive suppression of the roll angle affects the safety of the vehicle, so that the driver and passengers feel comfortable, and the comfort of the vehicle is improved.

[0114] In one embodiment, the control method specifically includes: when the lateral acceleration of the electric vehicle 10 is less than the acceleration threshold, controlling the torque output by the active lateral stabilizer bar 30 of the electric vehicle 10 to increase as the height difference between a left wheel and a right wheel increases. When the lateral acceleration of the electric vehicle 10 is greater than or equal to the acceleration threshold, controlling the active lateral stabilizer bar 30 of the electric vehicle 10 to adjust the output torque so that the height difference between a left wheel and a right wheel is at a preset value, and the preset value increases as the lateral acceleration of the electric vehicle 10 increases.

[0115] When the speed of the electric vehicle 10 is low or the steering wheel angle is small, the lateral acceleration generated by the electric vehicle 10 is small, and the control target of the roll angle of the electric vehicle 10 should be to suppress the roll angle of the electric vehicle 10 as much as possible, so that the driver and passengers feel safe and improve the comfort of the vehicle. Therefore, when the lateral acceleration is less than the acceleration threshold, the vehicle controller controls the active lateral stabilizer bar 30 to increase the output torque, and the torque output by the active lateral stabilizer bar 30 increases with the increase of the difference between the height of the left wheel and the height of the right wheel, so that the torque output by the active lateral stabilizer bar 30 increases with the increase of the roll angle of the electric vehicle, so that the anti-roll moment generated by the active lateral stabilizer bar 30 increases to reduce the roll angle of the electric vehicle 10.

[0116] When the speed of the electric vehicle 10 is high or the steering wheel angle is large, the lateral acceleration generated by the electric vehicle 10 is large. The control target of the roll angle of the electric vehicle 10 should be that the roll angle increases linearly with the lateral acceleration, so as not to suppress the change of the roll angle excessively, so that the driver has a proper operating experience, avoid excessive suppression affecting the safety of the vehicle, make the driver and passengers feel comfortable, and improve the comfort of the vehicle. Therefore, when the lateral acceleration is greater than or equal to the acceleration threshold, the vehicle controller controls the active lateral stabilizer bar 30 to adjust the output torque, and the torque output by the active lateral stabilizer bar 30 controls the roll angle of the electric vehicle to increase with the increase of the lateral acceleration, so that the anti-roll torque generated by the active lateral stabilizer bar 30 increases to adjust the rate of change of the roll angle of the electric vehicle 10. The corresponding relationship between the preset value and the lateral acceleration can be preset.

[0117] According to the solution of the present application, lateral acceleration feedforward is adopted to perform closed-loop control in conjunction with the wheel height difference, and the actuator torque of the active anti-roll bar is controlled to reduce the roll angle of the vehicle body, thereby avoiding inaccurate control caused by difficulties in measuring and estimating the roll angle of the vehicle body, improving the robustness of the system, and enhancing the driving experience and safety of the vehicle.

[0118] In one embodiment, the control method further includes: between the second moment t2 and the third moment t3, the steering wheel angle remains unchanged, and the difference between the driving torque of a left wheel and the driving torque of a right wheel is controlled to be reduced to zero.

[0119] At the second moment t2, the steering wheel angle of the electric vehicle 10 is stabilized during the turning process, and the steering wheel angle of the electric vehicle 10 increases to be equal to or greater than the preset angle. At this time, the torque output by the active lateral stabilizer bar 30 reaches a peak value, and the vehicle controller adjusts the yaw torque of the left and right drive motors to reach a peak value at the second moment t2, which can effectively suppress the overshoot of the roll angle. Between the second moment t2 and the third moment t3, the steering wheel angle remains unchanged, and the yaw torque required for the electric vehicle 10 to turn gradually decreases. The vehicle controller is used to control the difference between the driving torque of a left wheel and the driving torque of a right wheel to be reduced to zero.

[0120] In one embodiment, the vehicle controller is configured to control the driving torque of a left wheel and the driving torque of a right wheel to increase as the slip rate of a wheel of the electric vehicle 10 decreases.

[0121] Between the second moment t2 and the third moment t3, the wheel no longer slips, and the slip rate of the wheel decreases. At this time, the vehicle controller can increase the longitudinal torque. During the entire turning process, the vehicle controller performs closed-loop control with the speed of the drive motor. When the speed of the drive motor decreases, it means that the slip rate of the wheel of the electric vehicle 10 decreases, the road adhesion increases, and the torque output by the drive motor can be increased.

[0122] Continue to see Figure 4 The control method further includes: at a third moment t3 after the second moment t2, the steering wheel angle is smaller than the steering wheel angle at the second moment t2, and the vehicle controller is used to control the active anti-roll bar 30 to output reverse torque.

[0123] When the active stabilizer bar 30 outputs a reverse torque, the torsion direction of the stabilizer bar of the active stabilizer bar 30 is different, that is, the torsion direction of the stabilizer bar is different when the active stabilizer bar 30 outputs a torque and outputs a reverse torque.

[0124] At the third moment t3, the steering wheel starts to return to the center position, the steering wheel angle decreases, and the roll angle of the electric vehicle 10 starts to decrease. In order to prevent the roll angle from decreasing too quickly and causing discomfort to the driver and passengers, the vehicle controller controls the active lateral stabilizer bar 30 to output reverse torque to suppress the speed of the roll angle reduction.

[0125] At a fourth time t4 after the third time t3 , the steering wheel angle decreases to be less than the second preset angle, and the vehicle controller controls the active stabilizer bar 30 to reduce the reverse torque output.

[0126] At the fourth moment t4, the steering wheel is completely returned to the center position, and at this time, the roll angle overshoot phenomenon will also occur, causing discomfort to the driver and passengers. The vehicle controller controls the active lateral stabilizer bar 30 to output reverse torque from the third moment t3 to slow down the change of the roll angle of the electric vehicle. The reverse torque output at the fourth moment t4 reaches a peak value, which can effectively suppress the overshoot of the roll angle and improve the comfort of the driver and passengers.

[0127] In one embodiment, at the fourth moment t4, when the steering wheel angle of the electric vehicle 10 decreases to less than a second preset angle, the vehicle controller is used to control the difference between the driving torque of a left wheel and the driving torque of a right wheel to decrease to zero.

[0128] During the process of returning the steering wheel to center, the yaw angular velocity of the electric vehicle 10 decreases, so the required yaw moment decreases, and the vehicle controller actively adjusts the difference between the driving torque for the left wheels and the driving torque for the right wheels to zero.

[0129] According to the solution of the present application, lateral acceleration feedforward is adopted to perform closed-loop control in conjunction with the wheel height difference. The torque of the active stabilizer bar is controlled in coordination with the drive motor to generate a torque vector for control, thereby reducing the roll angle of the vehicle body, maximizing the lateral force of the tire, providing directional stability, enhancing the robustness of the system, and improving the driving experience and safety of the vehicle.

[0130] Combine the following Figure 5 and Figure 6The architecture and process of the roll angle controller of the electric vehicle 10 and the vehicle controller provided in the embodiment of the present application are described.

[0131] like Figure 5 As shown, the turning roll angle coordinated control of the electric vehicle 10 is mainly divided into three parts: lateral stability control, yaw control and slip control.

[0132] The lateral stability control mainly controls the roll angle of the vehicle body through the active lateral stabilizer bar 30. The yaw control mainly controls the yaw moment of the vehicle body through the torque distribution of the drive motor. The slip control mainly detects the slip rate of the wheel through the near-end detection of the drive motor speed, thereby performing torque control.

[0133] like Figure 5 As shown in the figure, the vehicle controller obtains vehicle status information such as lateral acceleration, longitudinal acceleration, yaw angular velocity, tire and body height of the electric vehicle 10 through the vehicle's sensors. The lateral stability control forms a feedforward through the lateral acceleration based on the obtained vehicle status information, considers the suppression of disturbances of the electric vehicle, increases the roll angle closed-loop control, and determines the torque output by the active lateral stabilizer bar.

[0134] The yaw feedforward control outputs the target angular velocity through the steering wheel command, and performs closed-loop control with the actual yaw angular velocity of the vehicle to output the vehicle's yaw moment. When distributing the torque of the left and right drive motors, the slip control of the tire slip, locking observation and torque adjustment results need to be used as distribution constraints to ensure that the single-wheel lateral force is maximized.

[0135] Slip control uses the resolver signal of the resolver sensor and the torque of the drive motor to form a proximal closed loop, identify wheel slippage and locking, and quickly adjust the torque.

[0136] It should be understood that the lateral stability control can be performed by the vehicle controller 20, the motor controller 40 or other separately provided controllers with control capabilities. The yaw control can be performed by the vehicle controller 20 or the motor controller 40. The slip control can be performed by the motor controller 40.

[0137] like Figure 6 As shown, first, the sensor collects the body posture information for body control. The required signals may include the vehicle speed signal from the vehicle speed sensor, the lateral acceleration, longitudinal acceleration, and yaw rate from the inertial measurement unit (IMU), the height difference between the tire and the body from the height sensor, and the resolver signal from the resolver sensor.

[0138] The vehicle controller calculates the torque required to be output by the active anti-roll bar 30 , the yaw torque required by the vehicle body, the slip rate of each tire, and the distributed torque of each drive motor through the vehicle body posture information.

[0139] The vehicle controller determines whether lateral stability adjustment is required based on the vehicle body posture information, the lateral acceleration and the height difference between the left and right tires of the vehicle body, whether yaw adjustment is required based on the target angular velocity and the current yaw angular velocity, and whether slip control is required based on the wheel slip rate. The torque required to be output by the active lateral stabilizer bar 30 and the torque output by each drive motor are adjusted according to the aforementioned control method.

[0140] Finally, the vehicle controller controls the output of torque signals to each drive motor, controls each drive motor to output the allocated torque, and controls the active lateral stabilizer bar 30 to output a determined torque to achieve cooperative control to suppress the roll angle of the electric vehicle 10 .

[0141] Control results comparison Figure 7 From the relationship diagram between the height difference of the left and right tires and time, it can be seen that compared with the traditional non-cooperative control, according to the scheme of the present application, the height difference of the left and right wheels is significantly reduced, which reduces the body roll and improves the comfort and operating confidence of the driver and passengers.

[0142] It should be understood that Figure 7 The values ​​in are only for reference and do not represent specific values. There may be certain deviations. The change trend is only used to illustrate the control changes of the present application scheme and does not limit the deviations in the actual control process.

[0143] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A control method for an electric vehicle, characterized in that: The control method is used to control the electric vehicle to reduce the turning roll during the turning process of the electric vehicle, and the control method includes: At a first moment, the steering wheel angle of the electric vehicle increases from zero, controlling the torque output by the active lateral stabilizer bar of the electric vehicle to increase and controlling the difference between the driving torque of a left wheel and a right wheel of the coaxial vehicle of the electric vehicle to increase; At a second moment after the first moment, the steering wheel angle of the electric vehicle increases from less than a preset angle to equal to or greater than the preset angle, controlling the torque output by the active stabilizer bar to decrease and controlling the difference between the driving torque of the left wheel and the driving torque of the right wheel to decrease.

2. The control method according to claim 1, characterized in that: The control method further comprises: At a third moment after the second moment, the steering wheel angle is smaller than the steering wheel angle at the second moment, and the active lateral stabilizer bar is controlled to output a reverse torque; At a fourth moment after the third moment, the steering wheel angle decreases to be less than a second preset angle, and the active stabilizer bar is controlled to reduce the reverse torque output.

3. The control method according to claim 2, characterized in that: The control method further comprises: Between the second time point and the third time point, the torque output by the active stabilizer bar is controlled to be reduced to zero.

4. The control method according to claim 1, characterized in that: The control method specifically includes: Between the first moment and the second moment, the torque output by the active stabilizer bar of the electric vehicle is controlled to increase as the height difference between the one left wheel and the one right wheel increases.

5. The control method according to claim 1, characterized in that: The control method specifically includes: Between the first moment and the second moment, the difference between the driving torque of the one left wheel and the driving torque of the one right wheel is controlled to increase as the steering wheel angle increases.

6. The control method according to claim 2, characterized in that: The control method further comprises: Between the second moment and the third moment, the steering wheel angle remains unchanged, and the difference between the driving torque of the left wheel and the driving torque of the right wheel is controlled to be reduced to zero.

7. The control method according to claim 1, characterized in that: The control method specifically includes: At a first moment, the leftward turning angle of the steering wheel of the electric vehicle increases from zero, and the driving torque of the left wheel is controlled to be smaller than the driving torque of the right wheel; At a first moment, the rightward turning angle of the steering wheel of the electric vehicle increases from zero, and the driving torque of the left wheel is controlled to be greater than the driving torque of the right wheel.

8. The control method according to claim 1 or 2, characterized in that: The control method further comprises: In response to an increase in the slip rate of any one wheel during a turning process of the electric vehicle, the driving torque of the any one wheel is controlled to decrease.

9. The control method according to claim 8, characterized in that: The control method further comprises: Between the first moment and the second moment, the driving torque of the one left wheel and the driving torque of the one right wheel are controlled to decrease and the difference between the driving torque of the one left wheel and the driving torque of the one right wheel is controlled to increase.

10. The control method according to claim 4, characterized in that: The control method specifically includes: When the lateral acceleration of the electric vehicle is less than an acceleration threshold, controlling the torque output by the active lateral stabilizer bar of the electric vehicle to increase as the height difference between the one left wheel and the one right wheel increases; When the lateral acceleration of the electric vehicle is greater than or equal to the acceleration threshold, the active anti-roll bar of the electric vehicle is controlled to adjust the output torque so that the height difference between the left wheel and the right wheel reaches a preset value, and the preset value increases with the increase of the lateral acceleration of the electric vehicle.

11. A vehicle controller for reducing the turning roll of an electric vehicle, characterized in that: The electric vehicle includes an active lateral stabilizer bar; the vehicle controller is used to: During the driving of the electric vehicle, when the steering wheel angle of the electric vehicle increases, When the lateral acceleration of the electric vehicle is less than the acceleration threshold, the torque output by the active lateral stabilizer bar is controlled to increase as the height difference between a coaxial left wheel and a coaxial right wheel of the electric vehicle increases; the difference between the driving torque of the left wheel and the driving torque of the right wheel is controlled to increase as the steering wheel angle increases; When the lateral acceleration of the electric vehicle is greater than or equal to the acceleration threshold, the active stabilizer bar is controlled to adjust the output torque so that the height difference between a coaxial left wheel and a coaxial right wheel of the electric vehicle reaches a preset value.

12. The vehicle controller according to claim 11, characterized in that: The vehicle controller is also used for: When the steering wheel angle of the electric vehicle increases to be equal to or greater than a preset angle, the torque output by the active stabilizer bar is controlled to decrease and the difference between the driving torque of the left wheel and the driving torque of the right wheel is controlled to decrease.

13. The vehicle controller according to claim 11, characterized in that: The vehicle controller is also used for: When the steering wheel angle of the electric vehicle decreases, controlling the active lateral stabilizer bar to output a reverse torque; When the steering wheel angle of the electric vehicle decreases to less than a second preset angle, the active anti-roll bar is controlled to reduce the reverse torque output; and the difference between the driving torque of the left wheel and the driving torque of the right wheel is controlled to decrease to zero.

14. The vehicle controller according to claim 11, characterized in that: The vehicle controller is also used for: In response to an increase in the slip rate of any one wheel during a turning process of the electric vehicle, the driving torque of the any one wheel is controlled to decrease.

15. An electric vehicle, characterized in that: The electric vehicle includes a vehicle controller and an active lateral stabilizer bar, wherein the vehicle controller is used to execute the method as described in any one of claims 1-10, and the active lateral stabilizer bar includes an actuator and a stabilizer bar, wherein the actuator is used to output torque to the stabilizer bar to twist the stabilizer bar.

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