Control method of electric vehicle, controller and electric vehicle

Abstract

The invention provides a control method of an electric vehicle, a controller and the electric vehicle, braking is performed through braking force output by a braking system when the opening degree of a brake pedal is increased from zero to a preset opening degree, and when the opening degree of the brake pedal is further increased from the preset opening degree, when the vehicle speed of the electric vehicle is larger than a preset vehicle speed, braking is performed through braking force output by a braking system. A braking system is assisted in braking by controlling the left front wheel and the right front wheel to rotate in opposite directions. Under the condition that the braking force output by the braking system cannot meet the braking requirement of the electric vehicle, auxiliary braking is achieved by actively controlling the left front wheel and the right front wheel to rotate in a specific mode, and therefore the braking capacity of the vehicle is further improved on the basis of the braking system; the braking capacity of the electric vehicle can be improved on the premise that the hardware structure is not changed, and finally the effect of reducing the driving risk of the vehicle is achieved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of new energy vehicles, and in particular to a control method of an electric vehicle, a controller and the electric vehicle. BACKGROUND

[0002] In the process of driving, when the driver needs to brake in the case of finding an obstacle, the driver can pass the intention of braking to the vehicle by the action of stepping on the brake pedal. After detecting that the driver steps on the brake pedal, the vehicle controls the braking system to brake the vehicle. However, in some cases, even if the driver steps on the brake pedal to make the vehicle control the braking system to brake, the vehicle cannot brake in a short distance due to the conditions such as too fast speed, too slippery road or braking system failure, which may lead to a collision with the obstacle and increase the driving risk of the vehicle.

[0003] Therefore, how to shorten the braking distance of the vehicle and thus reduce the driving risk of the vehicle is a problem to be solved. SUMMARY

[0004] The present application provides a control method of an electric vehicle, a controller and the electric vehicle, which actively controls the left front wheel and the right front wheel to rotate in opposite directions to assist braking, so as to shorten the braking distance of the vehicle and improve the effectiveness of the vehicle braking, thereby reducing the driving risk of the vehicle and ensuring the driving safety of the vehicle.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, a control method of an electric vehicle is provided, and the control method comprises: in the process of driving the electric vehicle, before a first time when a brake pedal opening degree of the electric vehicle starts to increase from zero, controlling the left front wheel and the right front wheel to rotate in the same direction with the change of a steering wheel turning angle. After the first time, before a second time when the brake pedal opening degree increases to a preset opening degree, controlling a braking system of the electric vehicle to output braking force to four wheels of the electric vehicle. After the second time, before a third time when the brake pedal opening degree starts to decrease, when a vehicle speed of the electric vehicle is greater than a preset vehicle speed, actively controlling the left front wheel and the right front wheel to rotate in opposite directions before the change of the steering wheel turning angle.

[0007] In this embodiment, before the brake pedal opening degree of the electric vehicle starts to increase from zero, the driver does not step on the brake pedal, considering that the vehicle does not need to be braked. After the brake pedal opening degree starts to increase from zero and before it increases to the preset opening degree, the driver steps on the brake pedal and the depth of stepping on the brake pedal does not exceed the threshold, considering that the vehicle needs to be braked and the braking intention is not strong or not urgent. After the brake pedal opening degree increases to the preset opening degree, the depth of the driver stepping on the brake pedal exceeds the threshold, considering that the vehicle needs to be braked and the braking intention is relatively strong or relatively urgent. After the brake pedal starts to decrease, the driver starts to release the brake pedal, considering that the vehicle needs to decrease the braking, until the brake pedal opening degree decreases to zero and the vehicle stops braking.

[0008] By not actively controlling the rotation of the left front wheel and the right front wheel before the first moment when the brake pedal opening degree starts to increase from zero, but controlling it according to the steering wheel steering angle input by the driver, the steering angle of the wheels when not needing to be braked conforms to the driving intention of the driver. By controlling the brake system to output braking force to the four wheels after the brake pedal opening degree starts to increase from zero and before it increases to the preset opening degree, the brake system controls the vehicle to brake when the vehicle needs to be braked and the braking intention is not strong or not urgent. By detecting that the speed of the electric vehicle is greater than the preset speed after the brake pedal opening degree increases to the preset opening degree, the automatic detection of the braking function failure or braking deficiency of the electric vehicle is realized. And in the case of needing to brake urgently and the braking function failing or braking deficiency, by actively controlling the left front wheel and the right front wheel to rotate in opposite directions without changing the steering wheel steering angle, the frictional force between the two front wheels in the longitudinal direction that hinders the driving of the electric vehicle after they rotate in opposite directions (the resultant force component of the two front wheels in the longitudinal direction) is increased on the basis of the braking force output by the brake system, so as to achieve the purpose of wheel auxiliary braking, shorten the braking distance of the vehicle and improve the braking effectiveness of the vehicle, thereby reducing the driving risk of the vehicle.

[0009] In an implementation form of the first aspect, the control method further comprises: after the third moment, before the fourth moment when the brake pedal opening degree decreases to zero, first controlling the amplitude of the rotation of the left front wheel and the right front wheel in opposite directions to decrease, and then controlling the braking force output by the brake system to decrease.

[0010] The reason why the rotation of the left front wheel and the right front wheel in opposite directions can achieve wheel auxiliary braking is that this rotation mode will increase the frictional force between the two front wheels in the longitudinal direction and the ground. However, it will also change the driving direction of the vehicle at the same time.

[0011] Based on this, in the process that the driver releases the brake pedal so that the brake pedal opening degree is reduced to zero, the embodiment first controls the amplitude of the wheel rotating in the opposite direction to be reduced, so that the wheel auxiliary braking is first reduced when the vehicle braking needs to be reduced, to ensure that the vehicle gradually returns to the original driving direction. Then, the brake system output brake force is further reduced, so that the vehicle brake force is further reduced to zero. In addition, in the embodiment, by gradually reducing the amplitude of the wheel rotating in the opposite direction, the wheel can be gradually transitioned from the auxiliary braking state to the normal rotating state, so that the steering angle of the wheel is prevented from suddenly changing, the tire force changes more smoothly, and the stability of the vehicle is improved.

[0012] In an implementation form of the first aspect, the control method further includes: after the second time, before the third time, when the steering wheel angle is greater than the preset angle, controlling the amplitudes of the left front wheel and the right front wheel rotating in the opposite direction to be unequal. For example, when the steering wheel turns right and the steering wheel angle is greater than the preset angle, the vehicle turns right, and the amplitude of the left front wheel rotating in the opposite direction is greater than the amplitude of the right front wheel rotating in the opposite direction; when the steering wheel turns left and the steering wheel angle is greater than the preset angle, the vehicle turns left, and the amplitude of the left front wheel rotating in the opposite direction is less than the amplitude of the right front wheel rotating in the opposite direction.

[0013] The wheel auxiliary braking changes the wheel steering angle and thus changes the driving direction of the vehicle. When the brake pedal opening degree is greater than the preset opening degree and the steering wheel angle is also greater than the preset angle, it indicates that the driver has a strong braking intention and also has a steering intention.

[0014] In order to avoid that the vehicle cannot turn according to the steering intention of the driver, the embodiment controls the amplitudes of the left front wheel and the right front wheel rotating in the opposite direction to be unequal, so that the left front wheel and the right front wheel increase the friction in the longitudinal direction to realize auxiliary braking, and the lateral force generated by the deflection of the left front wheel and the right front wheel cannot be completely offset, so that the vehicle turns through the remaining unoffset lateral force, which is in the same direction as the steering wheel angle. In this way, the vehicle turning ability is ensured while the wheel auxiliary braking is realized.

[0015] In an implementation form of the first aspect, the control method further includes: after the second time, before the third time, when the steering wheel angle is less than the preset angle, controlling the amplitudes of the left front wheel and the right front wheel rotating in the opposite direction to be equal.

[0016] In the embodiment, the steering wheel angle less than the preset angle is detected to detect that the driver does not have a steering intention. In this case, the amplitudes of the left front wheel and the right front wheel rotating in the opposite direction are controlled to be equal, so that the lateral forces of the left front wheel and the right front wheel can be exactly offset, and thus the vehicle can travel in a straight line according to the intention of the driver.

[0017] In an implementation form of the first aspect, the control method further comprises: after the second time instant, before the third time instant, controlling the magnitude of the rotation of the left front wheel and the right front wheel in opposite directions to increase with an increase of the longitudinal deceleration of the electric vehicle.

[0018] The resultant force component in the longitudinal direction generated by the rotation of the left front wheel and the right front wheel in opposite directions has a maximum value. When the resultant force component in the longitudinal direction reaches the maximum value, if the magnitude of the rotation of the left front wheel and the right front wheel in opposite directions continues to increase, the resultant force component in the longitudinal direction generated by the rotation of the left front wheel and the right front wheel will not continue to increase but decrease, while the resultant force component in the lateral direction generated by the rotation of the left front wheel and the right front wheel will increase. The two aforementioned resultant force components in the longitudinal direction are rearward, which can assist the vehicle to brake in the longitudinal direction. The resultant force component in the lateral direction generated by the rotation of the left front wheel and the right front wheel cannot assist the vehicle to brake in the longitudinal direction, but can generate a centripetal force in the lateral direction on the vehicle, which can cause the electric vehicle to slide in the lateral direction if the centripetal force is too large.

[0019] In the embodiment, the increase of the longitudinal deceleration of the vehicle indicates that the resultant force component in the longitudinal direction generated by the rotation of the left front wheel and the right front wheel in opposite directions is still increasing. In this case, by actively increasing the magnitude of the rotation of the left front wheel and the right front wheel in opposite directions, the resultant force component in the longitudinal direction can continue to increase (as close to the maximum value as possible), thereby further improving the braking force of the wheel auxiliary brake.

[0020] In an implementation form of the first aspect, the control method further comprises: after the second time instant, before the third time instant, controlling the magnitude of the rotation of the left front wheel and the right front wheel in opposite directions to decrease with an increase of the lateral deceleration of the electric vehicle.

[0021] When the lateral deceleration of the vehicle is detected to increase, it indicates that the resultant force component in the lateral direction generated by the rotation of the left front wheel and the right front wheel in opposite directions is increasing, while the resultant force component in the longitudinal direction generated by the rotation of the left front wheel and the right front wheel is decreasing. In this case, by actively decreasing the magnitude of the rotation of the left front wheel and the right front wheel in opposite directions, the embodiment can decrease the resultant force component in the lateral direction and increase the resultant force component in the longitudinal direction, thereby improving the braking force of the wheel auxiliary brake.

[0022] In an implementation form of the first aspect, the control method further comprises: after the second time instant, before the third time instant, controlling the magnitude of the rotation of the left front wheel and the right front wheel in opposite directions to be less than a preset magnitude.

[0023] The braking force generated by the wheel auxiliary braking can increase with the increase of the rotation amplitude within a certain range, but the increase of the braking force has an upper limit. When the rotation amplitudes of the left front wheel and the right front wheel rotating in opposite directions exceed a critical value, even if the rotation amplitudes further increase, the braking force generated by the wheel auxiliary braking will not increase, but the lateral centripetal force and the wear of the wheels will increase. The embodiment can effectively limit the maximum angle of the left front wheel and the right front wheel rotating in opposite directions by controlling the rotation amplitudes of the left front wheel and the right front wheel to be less than a preset amplitude, so as to reduce the wear of the tires and improve the driving stability of the vehicle on the basis of fully exerting the wheel auxiliary braking effect.

[0024] In an implementation form of the first aspect, the control method further includes: after the second time, before the third time, when the vehicle speed of the electric vehicle is greater than the preset vehicle speed, actively controlling the left rear wheel and the right rear wheel of the electric vehicle to rotate in opposite directions before the steering wheel rotation angle changes.

[0025] For a four-wheel steering vehicle, the left rear wheel and the right rear wheel of the vehicle can be controlled to rotate in opposite directions while the left front wheel and the right front wheel are controlled to rotate in opposite directions, so as to increase the friction force generated by the two rear wheels in the longitudinal direction to hinder the driving of the electric vehicle, and further increase the braking force of the wheel auxiliary braking.

[0026] In an implementation form of the first aspect, the control method further includes: after the second time, before the third time, controlling the rotation amplitude of the left front wheel to be greater than the rotation amplitude of the left rear wheel and the rotation amplitude of the right front wheel to be greater than the rotation amplitude of the right rear wheel.

[0027] When the vehicle brakes, the weight of the vehicle will shift from the rear wheels to the front wheels under the action of inertia, so that the tire load of the two front wheels increases sharply and the tire load of the two rear wheels decreases correspondingly. Since the friction force between the wheels and the road surface is positively related to the tire load, the greater the tire load, the greater the friction force between the wheels and the road surface. In the embodiment, by controlling the rotation amplitudes of the two front wheels to be greater than the rotation amplitudes of the two rear wheels, the front wheels with greater tire load can generate greater friction force, so as to further increase the braking force of the wheel auxiliary braking.

[0028] In addition, the forward shift of the weight of the vehicle also makes the rear wheels more likely to slide sideways under the action of the lateral force. By controlling the rotation amplitudes of the two rear wheels to be small, the embodiment can reduce the component of the resultant force of the two rear wheels in the lateral direction, so as to reduce the lateral force acting on the rear wheels, avoid the rear wheels from fishtailing, and improve the body stability of the vehicle during braking.

[0029] In an implementation form of the first aspect, the preset opening degree increases with the increase of the friction coefficient of the road surface on which the electric vehicle is located.

[0030] The higher the coefficient of friction of the road surface, the greater the friction between the wheels and the road surface after the braking system outputs braking force to the wheels, and the greater the braking force of the vehicle. In this embodiment, by setting a preset opening that increases with the coefficient of friction of the road surface, the brake pedal opening threshold for triggering wheel-assisted braking is increased when the braking force provided by the braking system is large. This avoids adding wheel-assisted braking when the braking force provided by the braking system is sufficient to meet the driver's braking intention, thereby ensuring the vehicle's braking effect while reducing the impact of wheel-assisted braking on vehicle driving.

[0031] Secondly, this application provides a controller for an electric vehicle. The controller is used to: during the operation of the electric vehicle, before the first moment when the brake pedal opening of the electric vehicle increases from zero, control the left and right front wheels to rotate in the same direction as the steering wheel angle changes. After the first moment, before the second moment when the brake pedal opening increases to a preset opening, control the braking system of the electric vehicle to output braking force to all four wheels of the electric vehicle. After the second moment, before the third moment when the brake pedal opening begins to decrease, when the vehicle speed exceeds a preset speed, actively control the left and right front wheels to rotate in opposite directions before the steering wheel angle changes.

[0032] In conjunction with the second aspect, in some implementations of the second aspect, the controller is also used to: after the third moment and before the fourth moment when the brake pedal opening decreases to zero, first control the left front wheel and the right front wheel to rotate in opposite directions to reduce the amplitude, and then control the braking force output by the braking system to reduce.

[0033] In conjunction with the second aspect, in some implementations of the second aspect, the controller is also used to: after the second moment and before the third moment, when the steering wheel angle is greater than a preset angle, control the left front wheel and the right front wheel to rotate in opposite directions with unequal amplitudes.

[0034] In conjunction with the second aspect, in some implementations of the second aspect, the controller is also used to: after the second moment and before the third moment, when the steering wheel angle is less than a preset angle, control the left front wheel and the right front wheel to rotate in opposite directions with equal amplitude.

[0035] In conjunction with the second aspect, in some implementations of the second aspect, the controller is also used to: after the second moment and before the third moment, control the amplitude of the left front wheel and the right front wheel to rotate in opposite directions to increase as the longitudinal deceleration of the electric vehicle increases.

[0036] In conjunction with the second aspect, in some implementations of the second aspect, the controller is also used to: after the second moment and before the third moment, control the amplitude of the left front wheel and the right front wheel rotating in opposite directions to decrease as the lateral deceleration of the electric vehicle increases.

[0037] In conjunction with the second aspect, in some implementations of the second aspect, the controller is also used to: after the second moment and before the third moment, control the left front wheel and the right front wheel to rotate in opposite directions by an amount less than a preset amount.

[0038] In conjunction with the second aspect, in some implementations of the second aspect, the controller is also used to: after the second moment and before the third moment, when the speed of the electric vehicle is greater than the preset speed, actively control the left and right rear wheels of the electric vehicle to rotate in opposite directions before the steering wheel angle changes.

[0039] In conjunction with the second aspect, in some implementations of the second aspect, the controller is also used to: after the second time point and before the third time point, control the rotation amplitude of the left front wheel to be greater than the rotation amplitude of the left rear wheel and the rotation amplitude of the right front wheel to be greater than the rotation amplitude of the right rear wheel.

[0040] In conjunction with the second aspect, in some implementations of the second aspect, the preset opening degree increases as the friction coefficient of the road surface where the electric vehicle is located increases.

[0041] Thirdly, this application provides an electric vehicle, which includes two corner modules and a controller. The two corner modules are used to drive the left front wheel and the right front wheel of the electric vehicle to rotate, respectively, and the controller is used to execute the control method of the electric vehicle in the first aspect and various embodiments of the first aspect.

[0042] Specifically, other beneficial effects can be referred to the beneficial effects described in the first aspect, and will not be repeated here. Attached Figure Description

[0043] Figure 1 A schematic diagram of a vehicle architecture provided for an embodiment of this application;

[0044] Figure 2 This is a schematic diagram of the structure of a steering system provided in an embodiment of this application;

[0045] Figure 3 A control timing diagram of a steering system provided in an embodiment of this application;

[0046] Figure 4 This is a schematic diagram of a first type of vehicle driving state provided in an embodiment of this application;

[0047] Figure 5 This is a schematic diagram of a second vehicle driving state provided in an embodiment of this application;

[0048] Figure 6 This is a schematic diagram of a third vehicle driving state provided in an embodiment of this application;

[0049] Figure 7This is a schematic diagram of the fourth vehicle driving state provided in the embodiments of this application;

[0050] Figure 8 This is a schematic diagram of the fifth vehicle driving state provided in the embodiments of this application;

[0051] Figure 9 This is a schematic diagram of the sixth vehicle driving state provided in the embodiments of this application;

[0052] Figure 10 This is a schematic diagram of the seventh vehicle driving state provided in the embodiments of this application;

[0053] Figure 11 This is a flowchart of a control method for an electric vehicle provided in an embodiment of this application. Detailed Implementation

[0054] The technical solutions in this application will now be described in conjunction with the accompanying drawings. The detailed descriptions and drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments.

[0055] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0056] During vehicle operation, when a driver encounters an obstacle or other situation requiring braking, they can signal this intention by pressing the brake pedal. Upon detecting this, the vehicle activates its braking system to apply the brakes. Therefore, the braking system is crucial for achieving braking. However, in some situations, even if the driver presses the brake pedal to engage the braking system, factors such as excessive speed, slippery roads, or brake system malfunction may prevent the vehicle from braking within a short distance, potentially leading to a collision with an obstacle and increasing driving risks.

[0057] In one possible implementation, vehicle safety can be improved by incorporating an additional backup braking system. When the braking force provided by the main braking system is insufficient to meet braking demands, the backup braking system is activated to supplement braking. However, this additional braking system requires more space and resources, increasing the overall design complexity and maintenance workload of the vehicle.

[0058] To address the aforementioned issues, this application provides a control method, controller, and electric vehicle for an electric vehicle. During the increase of the brake pedal opening from zero to a preset opening, braking is achieved through the braking force output by the braking system. As the brake pedal opening further increases from the preset opening, when the vehicle speed exceeds a preset speed, auxiliary braking is achieved by controlling the left and right front wheels to rotate in opposite directions. Thus, when the braking force output by the braking system is insufficient to meet the braking requirements of the electric vehicle, auxiliary braking is achieved by actively controlling the left and right front wheels to rotate in a specific manner. This further enhances the vehicle's braking capability based on the existing braking system, allowing the electric vehicle to shorten its braking distance and improve braking effectiveness without altering its hardware structure, thereby reducing driving risks and ensuring driving safety.

[0059] The vehicle architecture and system architecture provided in the embodiments of this application will be introduced below.

[0060] First, see Figure 1 , Figure 1 This is a schematic diagram of a vehicle architecture provided in an embodiment of this application.

[0061] Vehicle 10 may be an electric vehicle. For example... Figure 1 As shown, vehicle 10 includes a drive system 110, a braking system 120, a power battery 130 connected to the drive system 110 and the braking system 120, and a vehicle controller 190. The drive system 110 is used to drive vehicle 10. The braking system 120 is used to brake vehicle 10. The power battery 130 is used to provide electrical energy to the drive system 110 and the braking system 120. The vehicle controller 190 is used to control the drive system 110 to drive vehicle 10 and to control the braking system 120 to brake vehicle 10.

[0062] Based on their positions within the vehicle 10, the four wheels of vehicle 10 can be categorized as left front wheel 150, right front wheel 160, left rear wheel 170, and right rear wheel 180. According to axle arrangement, the left front wheel 150 and right front wheel 160 are coaxial and connected via the front axle. The left rear wheel 170 and right rear wheel 180 are coaxial and connected via the rear axle. According to their position, the left front wheel 150 and left rear wheel 170 are on the same side (left side), and the right front wheel 160 and right rear wheel 180 are on the same side (right side). In other words, among the four wheels of vehicle 10, the left front wheel 150 and right front wheel 160 are coaxial, the left rear wheel 170 and right rear wheel 180 are coaxial, the left front wheel 150 and left rear wheel 170 are on the same side, and the right front wheel 160 and right rear wheel 180 are on the same side.

[0063] In this application embodiment, the vehicle 10 can be any type of automobile, such as a sedan, truck, or passenger bus, or it can be a tricycle, two-wheeled vehicle, train, or other transportation device for carrying passengers or goods, or other types of vehicles powered by a power battery. This application embodiment does not limit this. The vehicle includes, but is not limited to, pure electric vehicles (pure EV / battery EV), hybrid electric vehicles (HEV), range-extended electric vehicles (REEV), plug-in hybrid electric vehicles (PHEV), and new energy vehicles (NEV).

[0064] The drive system 110 can be referred to as a powertrain. This application embodiment does not limit the specific type of powertrain; it is merely an example and not a limitation. The aforementioned powertrain can be a centralized powertrain, a hub motor powertrain, or a wheel-side motor powertrain. Specifically, the hub motor powertrain directly mounts the motor and reducer in the wheel rim, eliminating transmission components such as half-shafts, universal joints, differentials, and gearboxes; the wheel-side motor powertrain mounts the motor on the subframe.

[0065] The power battery 130 in this application embodiment can be a lithium-ion battery, lithium metal battery, lead-acid battery, nickel-cadmium battery, nickel-metal hydride battery, lithium-sulfur battery, lithium-air battery, or sodium-ion battery, etc., and this application does not limit it. In terms of scale, the power battery 130 in this application embodiment can be a single cell, a battery module, or a battery pack, and this application does not limit it. The power battery 130 can also supply power to other electrical devices in the vehicle, such as the vehicle's air conditioning and in-vehicle media player.

[0066] In addition to the drive system 110, braking system 120 and power battery 130, the vehicle 10 is also equipped with a steering system 140.

[0067] Next, see Figure 2 The diagram shows a structural schematic of a steering system, which introduces the steering system 140 provided in the embodiments of this application.

[0068] The steering system 140 includes multiple steering motors 141 and a steering controller 142 connected to the multiple steering motors 141. The steering motors 141 are connected to the kingpins of the wheels and are used to drive the kingpins to rotate, thereby adjusting the wheel deflection angle. The steering motors 141 of the steering system 140 can be integrated into a single corner module with the shock absorbers of the vehicle 10 suspension system, the wheel-end brakes of the braking system 120, and the hub motors of the drive system 110, or they can be set up independently of the shock absorbers, wheel-end brakes, and hub motors.

[0069] The number of steering motors 141 can be determined by the number of steering wheels in the vehicle 10, and the position of the steering motors 141 can be determined by the position of the steering wheels in the vehicle 10. For example, in a front-wheel steering four-wheel vehicle, two steering motors 141 can be provided, and the two steering motors 141 are respectively connected to the kingpins of the left front wheel 150 and the right front wheel 160 to adjust the deflection angle of the front wheels by driving the kingpins of the front wheels to rotate. For a four-wheel steering four-wheel vehicle, since both front wheels and both rear wheels of such a vehicle can be steered, four steering motors 141 can be provided in such a vehicle. The four steering motors 141 are respectively connected to the kingpins of the left front wheel 150, the right front wheel 160, the left rear wheel 170, and the right rear wheel 180, thereby driving the kingpins to rotate to make the four wheels rotate.

[0070] The steering system 140 can be a steer-by-wire system, where the steering wheel is not directly connected to the wheels via a mechanical structure and does not directly transmit force to the wheels. Instead, it acts as a signal generator, instructing the steering motor 141 to drive the wheels to turn by generating a steering wheel angle signal. The specific process of steering system 140 achieving steering includes: when the driver needs to steer, they transmit their steering control intention by turning the steering wheel. Simultaneously, a steering wheel angle sensor mounted on the steering column collects the steering wheel angle and generates a steering wheel angle signal, which is sent to the steering controller 142. Upon receiving the steering wheel angle signal, the steering controller 142 determines the required target torque based on the steering wheel angle indicated by the signal and further controls the steering motor 141 to output the target torque, driving the wheels to deflect by the corresponding angle according to the driver's steering control intention, ultimately achieving steering.

[0071] refer to Figure 2In one optional embodiment, the steering controller 142 may include a central controller 144 and multiple wheel-end controllers 143. The central controller 144 is connected to each of the multiple wheel-end controllers 143, and each of the multiple wheel-end controllers 143 is connected to a respective steering motor 141. After generating a steering wheel angle signal, the steering wheel angle sensor sends the steering wheel angle signal to the central controller 144. The central controller 144 then determines the target torque based on the steering wheel angle signal and sends a torque signal indicating the target torque to each of the wheel-end controllers 143, causing each wheel-end controller 143 to connect to its respective steering motor 141 according to the torque signal. The steering wheel angle sensor and the central controller 144, the central controller 144 and the wheel-end controllers 143, and the wheel-end controllers 143 and the steering motors 141 can be connected via a communication bus. The communication bus may include a controller area network (CAN) bus, a local interconnect network (LIN) bus, a high-speed fault-tolerant network protocol (FlexRay), or other types of buses, and is not limited thereto.

[0072] Furthermore, when the steering motor 141 in the steering system 140 is integrated into the corner module, the wheel end controller 143 of the steering system 140 can be a multi-functional integrated controller that can control the suspension system, braking system 120, and drive system 110 while controlling the steering motor 141.

[0073] The following combination Figure 3 A control timing diagram of a steering system is shown, and the control method for an electric vehicle provided in this application is described in detail. The control method described below is specifically executed by the controller of the vehicle 10.

[0074] See Figure 3 t1 is the first moment when the brake pedal opening of the electric vehicle starts to increase from zero, t2 is the second moment when the brake pedal opening increases to the preset opening, t3 is the third moment when the brake pedal opening starts to decrease, and t4 is the fourth moment when the brake pedal opening decreases to zero.

[0075] The brake pedal is the trigger for the vehicle's braking signal. When braking is required, the driver can press the brake pedal to transmit their braking intention to the vehicle, thereby controlling the vehicle's braking system. The degree of brake pedal opening further reflects the strength of the driver's braking intention or the urgency of braking. A larger brake pedal opening indicates a stronger braking intention or urgency; a smaller brake pedal opening indicates a weaker braking intention or urgency.

[0076] During the movement of vehicle 10, before the first moment t1, the road is clear and vehicle 10 is moving smoothly. The driver has no intention to brake and does not apply the brake pedal. In this situation, when the driver turns the steering wheel of vehicle 10, the steering wheel angle sensor connected to the steering wheel will collect the steering wheel angle and send it to the steering controller 142. The steering controller 142 then controls the steering motors 141 of the left front wheel 150 and the right front wheel 160 according to the changing steering wheel angle, driving the left front wheel 150 and the right front wheel 160 to rotate in the same direction as the steering wheel angle changes. At this time, see... Figure 4 The first schematic diagram of the vehicle's driving state is shown, taking a steering wheel angle to the right as an example. Both the left front wheel 150 and the right front wheel 160 deflect to the right by an angle. In one embodiment, for a four-wheel steering vehicle, before the first moment t1, the left rear wheel 170 and the right rear wheel 180 can also rotate in the same direction as the steering wheel angle changes.

[0077] After the first moment t1, the driver observes the emergency and intends to brake, then presses the brake pedal to increase the opening of the brake pedal from zero. The braking system 120 of the vehicle 10 begins to output braking force to the four wheels, and the vehicle speed begins to decrease.

[0078] After the first moment t1 when the brake pedal opening begins to increase, and before the second moment t2 when the brake pedal opening increases to the preset opening, the driver's braking intention is still in its early stages, and the braking force output by the braking system 120 is sufficient to meet the driver's braking needs. At this time, if the driver turns the steering wheel, the left front wheel 150 and the right front wheel 160 will rotate in the same direction as the steering wheel angle changes. For vehicles with four-wheel steering, the left rear wheel 170 and the right rear wheel 180 can also rotate in the same direction as the steering wheel angle changes.

[0079] As the emergency situation develops further, the driver's braking intention increases, and the brake pedal opening continues to increase to a preset opening, and may continue to increase to a level greater than the preset opening. In an optional implementation, the preset opening can be set as needed, for example, it can be 50%, 60%, 70%, etc. In one embodiment, the preset opening can also increase as the coefficient of friction of the road surface where the vehicle 10 is located increases.

[0080] After the brake pedal opening increases to the preset opening at time t2, and before the brake pedal opening begins to decrease at time t3, when the vehicle speed is less than or equal to the preset vehicle speed, although the driver's braking intention increases, the braking force output by the braking system 120 can still meet the driver's braking needs. At this time, braking can continue to be performed solely by the braking force output by the braking system 120. Simultaneously, if the driver turns the steering wheel, the left front wheel 150 and the right front wheel 160 will rotate in the same direction as the steering wheel angle changes. For vehicles with four-wheel steering, the left rear wheel 170 and the right rear wheel 180 will also rotate in the same direction as the steering wheel angle changes.

[0081] After the brake pedal opening increases to the preset opening at a second time t2, and before the brake pedal opening begins to decrease at a third time t3, when the vehicle speed is greater than or equal to the preset vehicle speed, the braking force output by the braking system 120 is no longer sufficient to meet the driver's braking needs. Therefore, to further satisfy the driver's strong or urgent braking intentions, before the steering wheel angle changes (i.e., when the steering wheel angle has not changed), the steering controller 142 actively controls the left front wheel 150 and the right front wheel 160 to rotate in opposite directions. Actively controlling wheel steering means that the steering controller 142 does not control wheel steering based on the steering wheel angle signal, but instead controls wheel steering independently.

[0082] In one embodiment, the left front wheel 150 and the right front wheel 160 rotate in opposite directions; for example, the left front wheel 150 rotates to the right and the right front wheel 160 rotates to the left. See also... Figure 5 The second vehicle driving state diagram shows that the left front wheel 150 and the right front wheel 160 are respectively deflected at an angle to the inside of the vehicle's longitudinal axis, and the two front wheels can form an inward V-shape.

[0083] In another embodiment, the left front wheel 150 and the right front wheel 160 rotate in opposite directions; alternatively, the left front wheel 150 rotates to the left and the right front wheel 160 rotates to the right. See also... Figure 6 The diagram shows the third type of vehicle driving state, where the left front wheel 150 and the right front wheel 160 are respectively deflected at an angle to the outside of the vehicle's longitudinal axis, and the two front wheels can form an outward V-shape.

[0084] In one alternative implementation, the preset vehicle speed can be set by the driver as needed, or it can be preset at the factory. For example, the preset vehicle speed can be 50 km / h, 40 km / h, 30 km / h, etc.

[0085] After the left front wheel 150 and the right front wheel 160 rotate in opposite directions, the left front wheel 150 and the right front wheel 160 will form an "inward" or "outward" position. This "inward" or "outward" position will cause the left front wheel 150 and the right front wheel 160 to have a sideslip angle relative to the forward direction of the vehicle 10, and further increase the friction between the wheels and the road surface. The longitudinal component of the friction force of the vehicle 10 is opposite to the direction of travel of the vehicle 10, which will hinder the forward movement of the vehicle 10. This, combined with the braking force output by the braking system 120, will jointly achieve braking of the vehicle 10, and the rate of decrease in vehicle speed can be increased.

[0086] With the control method of this embodiment, when the driver's braking intention is weak, braking is performed only through the braking system 120. The left front wheel 150 and the right front wheel 160 still change in the same direction with the steering wheel angle, allowing the left front wheel 150 and the right front wheel 160 to fully utilize their steering function. When the driver's braking intention increases further to the point that the braking system 120 alone cannot meet it, the left front wheel 150 and the right front wheel 160 are actively controlled to rotate in opposite directions, providing auxiliary braking through the wheels and further increasing the braking force of the vehicle 10. This satisfies the driver's braking intention, allowing the vehicle 10 to increase braking force without changing its hardware structure, shortening the vehicle braking distance and improving the vehicle braking effectiveness, thereby reducing driving risks and ensuring vehicle driving safety.

[0087] In one alternative implementation, when a malfunction of the braking system 120 is detected after the second time t2 and before the third time t3, the left front wheel 150 and the right front wheel 160 can also be actively controlled to rotate in opposite directions.

[0088] In the four-wheel steering vehicle 10, both front wheels and both rear wheels can steer. To further enhance the braking effect, in one possible implementation, for the four-wheel steering vehicle 10, after the second time t2 and before the third time t3, when the vehicle speed of 10 exceeds a preset speed or when a malfunction of the braking system 120 is detected, the left rear wheel 170 and the right rear wheel 180 of the vehicle 10 are actively controlled to rotate in opposite directions before the steering wheel angle changes.

[0089] In one embodiment, for a four-wheel steering vehicle 10, while controlling the left front wheel 150 and the right front wheel 160 to rotate in opposite directions, the left rear wheel 170 and the right rear wheel 180 of the vehicle 10 are also controlled to rotate in opposite directions. The left front wheel 150 and the left rear wheel 170 may rotate in the same direction, and the right front wheel 160 and the right rear wheel 180 may rotate in the same direction.

[0090] See Figure 7The diagram showing the fourth vehicle driving state shows that the left front wheel 150 and the right front wheel 160 are each deflected at an angle towards the inside of the vehicle's longitudinal axis, and the two front wheels can form an inward-pointing V-shape. The left rear wheel 170 and the right rear wheel 180 are also each deflected at an angle towards the inside of the vehicle's longitudinal axis, and the two rear wheels can also form an inward-pointing V-shape.

[0091] See Figure 8 The diagram shows the fifth type of vehicle driving state. The left front wheel 150 and the right front wheel 160 are respectively deflected at an angle to the outside of the longitudinal axis of the vehicle body, and the two front wheels can form an outward V-shape. The left rear wheel 170 and the right rear wheel 180 are also respectively deflected at an angle to the outside of the longitudinal axis of the vehicle body, and the two rear wheels can also form an outward V-shape.

[0092] In another embodiment, for a four-wheel steering vehicle 10, while controlling the left front wheel 150 and the right front wheel 160 to rotate in opposite directions, the left rear wheel 170 and the right rear wheel 180 of the vehicle 10 are also controlled to rotate in opposite directions. This can be the case that the left front wheel 150 and the left rear wheel 170 rotate in opposite directions, and the right front wheel 160 and the right rear wheel 180 rotate in opposite directions.

[0093] See Figure 9 The diagram shows the sixth type of vehicle driving state. The left front wheel 150 and the right front wheel 160 are respectively deflected at an angle to the inside of the vehicle's longitudinal axis, so that the two front wheels can form an inward V-shape. The left rear wheel 170 and the right rear wheel 180 are respectively deflected at an angle to the outside of the vehicle's longitudinal axis, so that the two rear wheels can form an outward V-shape.

[0094] See Figure 10 The diagram showing the seventh vehicle driving state shows that the left front wheel 150 and the right front wheel 160 are deflected at an angle to the outside of the vehicle's longitudinal axis, so that the two front wheels can form an outward V-shape. The left rear wheel 170 and the right rear wheel 180 are deflected at an angle to the inside of the vehicle's longitudinal axis, so that the two rear wheels can form an inward V-shape.

[0095] After the third moment t3 and before the fourth moment t4 when the brake pedal opening decreases to zero, the executable controls for reducing the vehicle's braking force include reducing the braking force provided by the wheel auxiliary brakes and reducing the braking force provided by the braking system 120.

[0096] In one embodiment, after the third time t3 and before the fourth time t4 when the brake pedal opening decreases to zero, the amplitude of rotation of the left front wheel 150 and the right front wheel 160 in opposite directions can be reduced first, and then the braking force output by the braking system 120 can be reduced. For vehicles with four-wheel steering, while reducing the amplitude of rotation of the left front wheel 150 and the right front wheel 160 in opposite directions, the amplitude of rotation of the left rear wheel 170 and the right rear wheel 180 in opposite directions can also be reduced.

[0097] The reason why wheel-assisted braking can be achieved by controlling the left front wheel 150 and the right front wheel 160 to rotate in opposite directions is that this rotation increases the longitudinal friction between the two front wheels and the ground. However, this also changes the driving direction of the vehicle 10. Based on this, in this embodiment, during the process of the driver releasing the brake pedal and reducing the brake pedal opening to zero, the amplitude of the rotation of the left front wheel 150 and the right front wheel 160 in opposite directions is first reduced, so that when it is necessary to reduce the braking of the vehicle 10, the wheel-assisted braking is reduced first to ensure that the vehicle gradually returns to its original driving direction. Then, the braking force output by the braking system 120 is reduced, so that the braking force of the vehicle 10 is further reduced to zero. In addition, by gradually reducing the amplitude of the rotation of the left front wheel 150 and the right front wheel 160 in opposite directions in this embodiment, the left front wheel 150 and the right front wheel 160 can gradually transition from the auxiliary braking state to the normal rotation state, thereby avoiding sudden changes in the steering angle of the left front wheel 150 and the right front wheel 160, making the change in the resultant force of the tires smoother, thereby improving the stability of the vehicle 10.

[0098] The following details the specific methods for controlling the left front wheel 150 and the right front wheel 160 to rotate in opposite directions. For four-wheel steering vehicles, the specific control methods for controlling the left rear wheel 170 and the right rear wheel 180 to rotate in opposite directions are similar (the left front wheel 150 and right front wheel 160 can be replaced with the left rear wheel 170 and right rear wheel 180), and will not be elaborated further below.

[0099] In one implementation, after the second time t2 and before the third time t3, when the steering wheel angle is greater than a preset angle, the left front wheel 150 and the right front wheel 160 are controlled to rotate in opposite directions with unequal amplitudes.

[0100] Specifically, when the steering wheel angle exceeds a preset angle, it is assumed that the driver intends to turn, and the vehicle needs to turn. The preset angle can be set according to needs and can be a small angle, such as 15°, 10°, 8°, etc.

[0101] For example, when the steering wheel turns to the right at an angle greater than a preset angle, and the vehicle 10 turns to the right, the left front wheel 150 rotates in the opposite direction by a greater amount than the right front wheel 160 rotates in the opposite direction. When the steering wheel turns to the left at an angle greater than a preset angle, and the vehicle 10 turns to the left, the left front wheel 150 rotates in the opposite direction by a less than the right front wheel 160 rotates in the opposite direction.

[0102] Wheel-assisted braking changes the wheel steering angle, thereby changing the driving direction of vehicle 10. When the brake pedal opening is greater than the preset opening and the steering wheel angle is also greater than the preset angle, it indicates that the driver has both braking and steering intentions.

[0103] To prevent the vehicle 10 from failing to steer according to the driver's steering intention, this embodiment controls the left front wheel 150 and the right front wheel 160 to rotate at unequal amplitudes in opposite directions. This increases the longitudinal friction of the left front wheel 150 and the right front wheel 160 to achieve auxiliary braking, while also allowing the lateral force generated by the deflection of the left front wheel 150 and the right front wheel 160 to steer the vehicle 10. This uncompensated lateral force is in the same direction as the steering wheel angle. In this way, the vehicle 10's steering ability is ensured while the wheels provide auxiliary braking.

[0104] In one implementation, after the second time t2 and before the third time t3, when the steering wheel angle is less than a preset angle, the left front wheel 150 and the right front wheel 160 are controlled to rotate in opposite directions with equal amplitude.

[0105] If the steering wheel angle is less than the preset angle, it indicates that the driver has no intention to steer. Therefore, in order to ensure that the vehicle 10 travels in a straight line as intended by the driver, the left front wheel 150 and the right front wheel 160 should be controlled to rotate in opposite directions with equal amplitude, so that the lateral forces of the left front wheel 150 and the right front wheel 160 can be exactly canceled out.

[0106] In one implementation, after the second time t2 and before the third time t3, the amplitude of the left front wheel 150 and the right front wheel 160 rotating in opposite directions increases as the longitudinal deceleration of the vehicle 10 increases.

[0107] The longitudinal resultant force component generated by the left front wheel 150 and the right front wheel 160 rotating in opposite directions has a maximum value. Once this maximum value is reached, if the left front wheel 150 and the right front wheel 160 continue to increase their rotation in opposite directions, the longitudinal resultant force component will decrease instead of increase. Simultaneously, the lateral resultant force component will increase. The aforementioned rearward longitudinal resultant force component of the two wheels can assist the vehicle in longitudinal braking, but the lateral resultant force component not only fails to assist braking but also generates a lateral centripetal force, causing the vehicle to sideslip.

[0108] In this embodiment, by detecting an increase in the longitudinal deceleration of vehicle 10, it is indicated that the longitudinal resultant force component generated by the left front wheel 150 and the right front wheel 160 rotating in opposite directions is still increasing. In this case, by actively increasing the amplitude of the left front wheel 150 and the right front wheel 160 rotating in opposite directions, the longitudinal resultant force component can continue to increase (as close as possible to its maximum value), further enhancing the braking force of the wheel auxiliary braking.

[0109] In one implementation, after the second time t2 and before the third time t3, the amplitude of the left front wheel 150 and the right front wheel 160 rotating in opposite directions decreases as the lateral deceleration of the vehicle 10 increases.

[0110] When the lateral deceleration of the detected vehicle 10 increases, it indicates that the resultant force component in the lateral direction generated by the left front wheel 150 and the right front wheel 160 rotating in opposite directions is increasing, while the resultant force component in the longitudinal direction is decreasing. In this case, this embodiment, by actively reducing the amplitude of the left front wheel 150 and the right front wheel 160 rotating in opposite directions, can reduce the resultant force component in the lateral direction while increasing the resultant force component in the longitudinal direction, thereby improving the braking force of the wheel auxiliary braking.

[0111] In one implementation, after the second time t2 and before the third time t3, the left front wheel 150 and the right front wheel 160 are controlled to rotate in opposite directions by an amplitude less than a preset amplitude.

[0112] The preset amplitude can be set according to requirements. The preset amplitude corresponds to the rotation angle at which the resultant force in the longitudinal direction generated by the two front wheels rotating in opposite directions reaches its maximum value. By testing various rotation angles of the two front wheels, the magnitude of the resultant force in the longitudinal direction generated by the two front wheels at various rotation angles can be calculated, thereby determining the rotation angle at which the resultant force in the longitudinal direction reaches its maximum value, and thus determining the preset amplitude. For example, the preset amplitude can be 10°, 15°, 18°, etc.

[0113] The braking force generated by wheel-assisted braking increases with the increase of rotation amplitude within a certain range, but there is an upper limit to this increase in braking force. When the rotation amplitude of the left front wheel 150 and the right front wheel 160 in opposite directions exceeds a critical value, even if the rotation amplitude increases further, the braking force generated by wheel-assisted braking will not increase accordingly, but it will increase the lateral centripetal force and the wear on the wheels. This embodiment effectively limits the maximum angle of rotation of the left front wheel 150 and the right front wheel 160 in opposite directions by controlling the rotation amplitude of the left front wheel 150 and the right front wheel 160 in opposite directions to be less than a preset amplitude, thereby reducing tire wear and improving vehicle driving stability while fully utilizing the wheel-assisted braking efficiency.

[0114] In one implementation, for a four-wheel steering vehicle, after the second time t2 and before the third time t3, the left front wheel 150 is controlled to rotate at a greater angle than the left rear wheel 170, and the right front wheel 160 is controlled to rotate at a greater angle than the right rear wheel 180.

[0115] When vehicle 10 brakes, its weight shifts from the rear wheels to the front wheels due to inertia, causing a sharp increase in the tire load on the two front wheels and a corresponding decrease in the tire load on the two rear wheels. Since the friction between the wheels and the road surface is positively correlated with the tire load—the greater the tire load, the greater the friction—this embodiment controls the rotation amplitude of the front wheels to be greater than that of the rear wheels. This allows the front wheels, with their larger tire load, to generate greater friction, thereby maximizing braking performance.

[0116] Meanwhile, considering the weight of the vehicle 10 moving forward, the rear wheels are more prone to sideslip under lateral forces. This embodiment controls the rear wheel rotation to a smaller extent, which reduces the lateral component of friction on the vehicle 10, thereby reducing the lateral force on the rear wheels, preventing rear wheel fishtailing, and improving the vehicle stability of the vehicle 10 during braking.

[0117] Next, for ease of understanding, as an example, Figure 11 A flowchart of a control method for an electric vehicle is provided. In the control method provided in this embodiment, the controller of the vehicle 10 can execute the following steps S101-S107.

[0118] Step S101: Determine whether the driver has pressed the brake pedal.

[0119] If the driver does not press the brake pedal, proceed from step S101 to step S102.

[0120] If the driver presses the brake pedal, the process proceeds from step S101 to step S103.

[0121] Step S102: Control the left front wheel 150 and the right front wheel 160 to rotate in the same direction as the steering wheel angle changes.

[0122] After step S102 is completed, it can be done as follows: Figure 11 The process can either return from step S102 to step S101 for a loop judgment, or directly end the current control (not shown in the attached figure).

[0123] Step S103: Determine whether the brake pedal opening of the vehicle has increased to a level greater than the preset opening.

[0124] If the brake pedal opening of the vehicle does not increase to a level greater than the preset opening, the process proceeds from step S103 to step S104.

[0125] If the brake pedal opening of the vehicle increases to a level greater than the preset opening, the process proceeds from step S103 to step S105.

[0126] In step S104, the braking system 120 of the vehicle 10 is controlled to output braking force to the four wheels of the electric vehicle 10.

[0127] After step S104 is completed, it can be done as follows: Figure 11 The process can either return from step S104 to step S103 for a loop judgment, or directly end the current control (not shown in the attached figure).

[0128] In step S105, when the vehicle speed of vehicle 10 is greater than the preset speed, the steering controller 142 actively controls the left front wheel 150 and the right front wheel 160 to rotate in opposite directions before the steering wheel angle changes.

[0129] Step S106: Determine whether the vehicle's brake pedal opening has begun to decrease.

[0130] If the brake pedal opening begins to decrease, proceed from step S106 to step S107.

[0131] If the brake pedal opening does not begin to decrease, proceed from step S106 back to step S107.

[0132] In step S107, first control the left front wheel 150 and the right front wheel 160 to rotate in opposite directions to reduce the amplitude, and then control the braking force output by the braking system 120 to reduce the braking force.

[0133] In this embodiment of the application, a controller for an electric vehicle is also provided, and the control method executed by the controller is the same as described above. Figures 2-11 The control functions implemented by the relevant control methods correspond to the control functions.

[0134] For example, when the drive system 110, braking system 120, steering system 140, and suspension system are integrated in a corner module, the controller of this embodiment may include a corner module controller. When the drive system 110, braking system 120, steering system 140, and suspension system are not integrated, the controller of this embodiment may include a steering controller 142 for the steering system 140 and a brake controller for the braking system 120 (not shown in the figures). Furthermore, when it comes to control at the vehicle-wide level of the vehicle 10, the controller of this embodiment may also include a vehicle controller 190.

[0135] Specifically, the controller is used for:

[0136] During the operation of the electric vehicle, before the first moment t1 when the brake pedal opening increases from zero, the left front wheel 150 and the right front wheel 160 are controlled to rotate in the same direction as the steering wheel angle changes. After the first moment t1, before the second moment t2 when the brake pedal opening increases to a preset opening, the braking system 120 of the electric vehicle is controlled to output braking force to all four wheels of the electric vehicle. After the second moment t2, before the third moment t3 when the brake pedal opening begins to decrease, when the vehicle speed exceeds a preset speed, the left front wheel 150 and the right front wheel 160 are actively controlled to rotate in opposite directions before the steering wheel angle changes.

[0137] The controller is also used to: after the third time t3 and before the fourth time t4 when the brake pedal opening decreases to zero, first control the left front wheel 150 and the right front wheel 160 to reduce the amplitude of rotation in opposite directions, and then control the braking force output by the braking system 120 to decrease.

[0138] The controller is also used to: after the second time t2 and before the third time t3, when the steering wheel angle is greater than a preset angle, control the left front wheel 150 and the right front wheel 160 to rotate in opposite directions with unequal amplitudes.

[0139] The controller is also used to: after the second time t2 and before the third time t3, when the steering wheel angle is less than a preset angle, control the left front wheel 150 and the right front wheel 160 to rotate in opposite directions with equal amplitude.

[0140] The controller is also used to: after the second time t2 and before the third time t3, control the left front wheel 150 and the right front wheel 160 to rotate in opposite directions as the longitudinal deceleration of the electric vehicle 10 increases.

[0141] The controller is also used to: after the second time t2 and before the third time t3, control the amplitude of the left front wheel 150 and the right front wheel 160 rotating in opposite directions to decrease as the lateral deceleration of the electric vehicle 10 increases.

[0142] The controller is also used to: after the second time t2 and before the third time t3, control the left front wheel 150 and the right front wheel 160 to rotate in opposite directions by a smaller than a preset amount.

[0143] The controller is also used to: after the second time t2 and before the third time t3, when the speed of the electric vehicle is greater than the preset speed, actively control the left rear wheel 170 and the right rear wheel 180 of the electric vehicle to rotate in opposite directions before the steering wheel angle changes.

[0144] The controller is also used to: after the second time t2 and before the third time t3, control the left front wheel 150 to rotate at a greater angle than the left rear wheel 170 and the right front wheel 160 to rotate at a greater angle than the right rear wheel 180.

[0145] In this embodiment of the application, an electric vehicle is also provided. The electric vehicle includes two corner modules and a controller. The two corner modules are respectively used to drive the left front wheel 150 and the right front wheel 160 of the electric vehicle to rotate. The control method executed by the controller is the same as described above. Figures 2-11 The control functions implemented by the relevant control methods correspond to the control functions. In one embodiment, the electric vehicle may also include four corner modules, which are respectively used to drive the left front wheel 150, right front wheel 160, left rear wheel 170 and right rear wheel 180 of the electric vehicle.

[0146] For more detailed information about the controller, please refer to the previous text. Figures 2-11 An introduction to the control methods of electric vehicles.

[0147] In the embodiments of this application, the words "exemplary," "for example," etc., are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design that is described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of the term "exemplary" is intended to present the concept in a concrete manner.

[0148] It should be understood that the term "embodiment" used throughout this specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, various embodiments throughout this specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0149] It should also be understood that in this application, "when," "if," "in the circumstances of," and "if" all refer to a situation where a corresponding action will be taken under certain objective circumstances, and are not time-limited. They do not require the device to perform a judgment action, nor do they imply any other limitations. Furthermore, in this application, the descriptions of conditions such as "when," "if," "in the circumstances of," and "if" can be understood as necessary conditions, without limiting whether the condition is a sufficient condition or a necessary and sufficient condition. For example, "in the case of A, execute B" can be understood as "if at least A is satisfied, execute B."

[0150] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A control method for an electric vehicle, characterized in that, The control method is used to control the rotation of the left and right front wheels of the electric vehicle to brake the electric vehicle, and the control method includes: During the operation of the electric vehicle, before the first moment when the brake pedal opening of the electric vehicle increases from zero, the left front wheel and the right front wheel are controlled to rotate in the same direction as the steering wheel angle changes. After the first moment and before the second moment when the brake pedal opening increases to a preset opening, the braking system of the electric vehicle is controlled to output braking force to the four wheels of the electric vehicle. After the second moment and before the third moment when the brake pedal opening begins to decrease, when the speed of the electric vehicle is greater than the preset speed, the left front wheel and the right front wheel are actively controlled to rotate in opposite directions before the steering wheel angle changes.

2. The control method according to claim 1, characterized in that, The control method further includes: After the third moment and before the fourth moment when the brake pedal opening decreases to zero, the amplitude of the left front wheel and the right front wheel rotating in opposite directions is first reduced, and then the braking force output by the braking system is reduced.

3. The control method according to claim 1, characterized in that, The control method further includes: After the second moment and before the third moment, when the steering wheel angle is greater than a preset angle, the left front wheel and the right front wheel are controlled to rotate in opposite directions with unequal amplitudes.

4. The control method according to claim 1, characterized in that, The control method further includes: After the second moment and before the third moment, when the steering wheel angle is less than a preset angle, the left front wheel and the right front wheel are controlled to rotate in opposite directions with equal amplitude.

5. The control method according to claim 1, characterized in that, The control method further includes: After the second time point and before the third time point, the magnitude of the rotation of the left front wheel and the right front wheel in opposite directions increases as the longitudinal deceleration of the electric vehicle increases.

6. The control method according to claim 1, characterized in that, The control method further includes: After the second moment and before the third moment, the magnitude of the rotation of the left front wheel and the right front wheel in opposite directions decreases as the lateral deceleration of the electric vehicle increases.

7. The control method according to claim 1, characterized in that, The control method further includes: After the second moment and before the third moment, the left front wheel and the right front wheel are controlled to rotate in opposite directions by a smaller amount than a preset amount.

8. The control method according to claim 1, characterized in that, The control method further includes: After the second moment and before the third moment, when the speed of the electric vehicle is greater than the preset speed, the left and right rear wheels of the electric vehicle are actively controlled to rotate in opposite directions before the steering wheel angle changes.

9. The control method according to claim 8, characterized in that, The control method further includes: After the second time point and before the third time point, the rotation amplitude of the left front wheel is controlled to be greater than that of the left rear wheel, and the rotation amplitude of the right front wheel is controlled to be greater than that of the right rear wheel.

10. The control method according to claim 1, characterized in that, The preset opening degree increases as the friction coefficient of the road surface where the electric vehicle is located increases.

11. A controller for an electric vehicle, characterized in that, The controller is used for: During the operation of the electric vehicle, before the first moment when the brake pedal opening of the electric vehicle increases from zero, the left front wheel and the right front wheel are controlled to rotate in the same direction as the steering wheel angle changes. After the first moment and before the second moment when the brake pedal opening increases to a preset opening, the braking system of the electric vehicle is controlled to output braking force to the four wheels of the electric vehicle. After the second moment and before the third moment when the brake pedal opening begins to decrease, when the speed of the electric vehicle is greater than the preset speed, the left front wheel and the right front wheel are actively controlled to rotate in opposite directions before the steering wheel angle changes.

12. The controller according to claim 11, characterized in that, The controller is also used for: After the third moment and before the fourth moment when the brake pedal opening decreases to zero, the amplitude of the left front wheel and the right front wheel rotating in opposite directions is first reduced, and then the braking force output by the braking system is reduced.

13. The controller according to claim 11, characterized in that, The controller is also used for: After the second moment and before the third moment, when the steering wheel angle is greater than a preset angle, the left front wheel and the right front wheel are controlled to rotate in opposite directions with unequal amplitudes.

14. The controller according to claim 11, characterized in that, The controller is also used for: After the second moment and before the third moment, when the steering wheel angle is less than a preset angle, the left front wheel and the right front wheel are controlled to rotate in opposite directions with equal amplitude.

15. An electric vehicle, characterized in that, The electric vehicle includes two corner modules and a controller. The two corner modules are used to drive the left front wheel and the right front wheel of the electric vehicle to rotate, respectively. The controller is used to execute the control method of the electric vehicle as described in any one of claims 1-10.

Images