Electric vehicle turning control method, vehicle controller and electric vehicle

Abstract

The invention provides an electric vehicle turning control method, a vehicle controller and an electric vehicle, and is applied to the technical field of electric vehicles. The control method is used for controlling a braking system and a driving system of the electric vehicle to reduce the turning radius of the electric vehicle in the turning process of the electric vehicle. The control method comprises the steps that at the first moment, the right turning angle of a steering wheel of the electric vehicle is increased from zero, and two front wheels of the electric vehicle are controlled to turn right; at a second moment after the first moment, the rightward turning angle of the steering wheel of the electric vehicle is increased to be larger than a first preset angle, and in the process that the driving system is controlled to output driving torque to the electric vehicle so as to drive the electric vehicle to run, a braking system of the electric vehicle is controlled to output braking force to two right wheels of the electric vehicle. On the basis, coordinated control over the driving system and the braking system is achieved, the turning radius of the electric vehicle can be reduced, and the driving direction can be rapidly changed in the turning process.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and in particular to a method for controlling turning of an electric vehicle, a vehicle controller and an electric vehicle. Background Art

[0002] During the driving process of electric vehicles, it is often necessary to drive the electric vehicle to turn. During conventional turning, the driver needs to control the movement of the electric vehicle according to the road conditions and actual driving conditions, combined with the adjustment of the steering wheel, throttle and gear position, so as to adjust the front direction of the electric vehicle to the desired driving direction. At present, the turning radius of electric vehicles is large. If the space for electric vehicles to travel is limited, such as narrow roads, it is difficult for the driver to accurately control the electric vehicle to quickly change the driving direction in a limited space, which increases the difficulty of turning the electric vehicle and affects the user's driving experience. Summary of the invention

[0003] The embodiments of the present application provide a method for controlling the turning of an electric vehicle, a vehicle controller, and an electric vehicle, which are used to reduce the turning radius of the electric vehicle and improve the driving experience of the user.

[0004] In a first aspect, an embodiment of the present application provides a control method for turning an electric vehicle, the control method being used to control a braking system and a driving system of the electric vehicle to reduce a turning radius of the electric vehicle during a turning process of the electric vehicle, the control method comprising:

[0005] At the first moment, the right turning angle of the steering wheel of the electric vehicle increases from zero, and the two front wheels of the electric vehicle are controlled to turn right;

[0006] At a second moment after the first moment, the steering wheel turning angle of the electric vehicle to the right increases to be greater than a first preset angle, and in the process of controlling the drive system to output driving torque to the electric vehicle to drive the electric vehicle, the brake system of the electric vehicle is controlled to output braking force to the two right wheels of the electric vehicle.

[0007] The above method reduces the turning radius of the electric vehicle when the electric vehicle turns right. Similar to the electric vehicle turning right, when the electric vehicle turns left, the control method provided in the embodiment of the present application includes:

[0008] At the first moment, the left turning angle of the steering wheel of the electric vehicle increases from zero, and the two front wheels of the electric vehicle are controlled to turn left;

[0009] At a second moment after the first moment, the steering wheel turning angle of the electric vehicle to the left increases to be greater than a first preset angle, and in the process of controlling the drive system to output driving torque to the electric vehicle to drive the electric vehicle, the brake system of the electric vehicle is controlled to output braking force to the two left wheels of the electric vehicle.

[0010] The first preset angle may be a larger preset angle, such as 70 degrees, 80 degrees, 90 degrees, etc. When the rightward turning angle of the steering wheel increases to be greater than the first preset angle, it can be considered that the electric vehicle needs to complete a right turn.

[0011] In this embodiment, in the scenario of controlling the turning of the electric vehicle, by setting a first preset angle, after the user turns the steering wheel to the right to an angle greater than the first preset angle, the drive system and the brake system of the electric vehicle are coordinated to control the vehicle to complete the turn. The coordinated control of the drive system and the brake system of the electric vehicle includes, in the process of the drive system driving the electric vehicle to drive, controlling the brake system of the electric vehicle to output a braking force to the two wheels on the inner side of the turn of the electric vehicle, and the braking force will provide an additional yaw moment to increase the yaw moment of the electric vehicle, and the increase in the yaw moment increases the yaw angular velocity of the electric vehicle, and the increase in the yaw angular velocity causes the vehicle to change the driving direction faster and the turning center of the electric vehicle moves to the inner side of the turn, thereby reducing the turning radius. In this way, the aforementioned coordinated control of the drive system and the brake system can reduce the turning radius of the electric vehicle and quickly change the driving direction during the turning process, reduce the difficulty of the electric vehicle turning in a limited space, and improve the maneuverability and driving experience of the electric vehicle.

[0012] In an implementation of the first aspect, the control method further includes: at a third moment after the second moment, in the process of controlling the braking system to output braking force to the two right wheels, controlling the driving torque output by the driving system to the electric vehicle to increase.

[0013] In some cases, if the braking force output by the braking system is too large, it may cause the wheels to lock and the electric vehicle to stall, affecting the normal driving of the vehicle.

[0014] In this embodiment, in the process of controlling the braking system to output braking force to the two right wheels, the driving torque output by the control drive system to the electric vehicle is increased to compensate for the drive of the electric vehicle, so that the electric vehicle avoids stalling due to the braking of the two right wheels by the braking system. In this way, while ensuring the normal driving of the electric vehicle, the turning radius of the electric vehicle is reduced by the yaw torque provided by the braking force.

[0015] In an implementation of the first aspect, the control method further includes: at a fourth moment after the third moment, the steering wheel turning angle to the right is reduced to less than a second preset angle, and the braking system is controlled to stop outputting braking force to the two right wheels.

[0016] The second preset angle is a smaller preset angle, such as 5 degrees, 10 degrees, 15 degrees, etc. It can be considered that when the rightward turning angle of the steering wheel is reduced to less than the second preset angle, the electric vehicle has completed the right turn or is about to complete the right turn.

[0017] In this embodiment, by detecting that the steering wheel turning angle to the right is reduced to less than a second preset angle, it is possible to automatically detect that the electric vehicle has completed a turn or is about to complete a turn, and at this time, the braking system is automatically controlled to stop outputting braking force to the two right wheels to ensure that the electric vehicle can drive normally after completing the turn.

[0018] In an implementation of the first aspect, the control method specifically includes: at a second moment, the steering wheel angle to the right increases to be greater than a first preset angle and the speed of the electric vehicle is a first speed, and the braking system is controlled to output a first braking force to the two right wheels; at a second moment, the steering wheel angle to the right increases to be greater than the first preset angle and the speed of the electric vehicle is a second speed, and the braking system is controlled to output a second braking force to the two right wheels; wherein, the first speed is less than the second speed, and the first braking force is less than the second braking force.

[0019] Since electric vehicles generate centrifugal force during turning, the centrifugal force makes the electric vehicle tend to slide outward. The greater the speed of the electric vehicle, the greater the centrifugal force of the electric vehicle, and the stronger the tendency of the electric vehicle to slide outward. If the tendency of the electric vehicle to slide outward cannot be overcome, it will be difficult for the electric vehicle to complete the turn in the desired direction, it will be difficult to reduce the turning radius, and there may be instability such as side slipping.

[0020] Thus, in this embodiment, when the steering wheel turns to the right at a angle greater than a first preset angle, the braking force output by the braking system is controlled to be larger when the speed of the electric vehicle is larger so that the centrifugal force is larger, and the braking force output by the braking system is controlled to be smaller when the speed of the electric vehicle is smaller so that the centrifugal force is smaller. This allows the component of the braking force in the lateral direction to balance the centrifugal force, overcome the tendency of the electric vehicle to slide outward, avoid unstable phenomena such as side slipping, and provide sufficient yaw torque for the electric vehicle at different speeds, thereby ensuring that the electric vehicle successfully turns right while reducing the turning radius of the electric vehicle.

[0021] In an implementation of the first aspect, the control method specifically includes: between the second moment and the fourth moment, controlling the braking system to increase the braking force output to the two right wheels as the speed of the electric vehicle increases.

[0022] In this embodiment, the braking force output by the braking system to the two right wheels is increased as the speed of the electric vehicle increases, so that when the electric vehicle is turning, when the centrifugal force changes with the speed of the vehicle, the braking force can be flexibly adjusted according to the speed, so that the component of the braking force in the lateral direction can balance the centrifugal force, overcome the tendency of the electric vehicle to slide outward, avoid unstable phenomena such as side slip, and provide sufficient yaw torque for the electric vehicle at different speeds, ensuring that the electric vehicle successfully turns right while reducing the turning radius of the electric vehicle.

[0023] In an implementation of the first aspect, the control method specifically includes: between the second moment and the fourth moment, controlling the braking system to increase the braking force output to the two right wheels as the steering wheel turning angle to the right increases.

[0024] During the turning process of the electric vehicle, the greater the steering wheel turns to the right, the stronger the user's intention to turn right is.

[0025] Thus, in this embodiment, the braking force output to the two right wheels by controlling the braking system increases as the steering wheel turns to the right. The greater the steering wheel turns to the right, the greater the braking force. The greater the braking force, the greater the yaw moment provided. The greater the yaw moment, the faster the electric vehicle changes its direction of travel and the smaller the turning radius, which can match the user's stronger intention to turn right and improve the driving experience.

[0026] In an implementation of the first aspect, the control method specifically includes: between the second moment and the fourth moment, controlling the braking system of the electric vehicle to output a braking force to the right front wheel that is greater than the braking force output to the right rear wheel.

[0027] Since the vertical load of the right front wheel is greater than the vertical load of the right rear wheel when the electric vehicle turns right, the maximum yaw moment that can be generated by the right front wheel is greater than the maximum yaw moment that can be generated by the right rear wheel.

[0028] Thus, in this embodiment, the braking force output to the right front wheel by the braking system of the electric vehicle is controlled to be greater than the braking force output to the right rear wheel, so as to match the yaw moment provided by the braking force of the right front wheel during the turning process of the electric vehicle to be greater than the yaw moment provided by the braking force of the right rear wheel, thereby avoiding unreasonable braking force output to the right front wheel or the right rear wheel, which may cause the electric vehicle to lose control and tire damage.

[0029] In an implementation of the first aspect, the control method specifically includes: between the third moment and the fourth moment, controlling the driving torque output by the drive system to the two front wheels of the electric vehicle to increase as the braking force output by the braking system to the right front wheel increases, or controlling the driving torque output by the drive system to the two rear wheels of the electric vehicle to increase as the braking force output by the braking system to the right rear wheel increases.

[0030] In a two-wheel drive or three-wheel drive electric vehicle, there is a situation where the drive system of the electric vehicle cannot output drive torque to a certain wheel alone, and according to the above implementation method, the braking force output by the braking system to the right front wheel and the right rear wheel is different.

[0031] Thus, in this embodiment, the driving torque output by the drive system to the two front wheels is associated with the braking force output by the brake system to the right front wheel, so that the driving torque output to the two front wheels increases with the increase of the braking force output to the right front wheel, and the driving torque output by the drive system to the two rear wheels is associated with the braking force output by the brake system to the right rear wheel, so that the driving torque output to the two rear wheels increases with the increase of the braking force output to the right rear wheel. This avoids the wheel locking caused by the excessive braking force without sufficient compensation for the drive, which affects the normal driving of the vehicle, and ensures that the electric vehicle does not stall due to the braking of the two right wheels by the brake system.

[0032] In an implementation of the first aspect, the control method specifically includes: between the third moment and the fourth moment, controlling the increase in the driving torque output by the driving system to increase as the steering wheel turns to the right.

[0033] When an electric vehicle is turning, the greater the steering wheel turns to the right, the stronger the user's intention to turn right. The stronger the user's intention to turn right, the greater the braking force, which may cause the wheels to lock and affect the normal driving of the vehicle.

[0034] Thus, in this embodiment, the increase in the driving torque output by the drive system to at least one wheel increases as the steering wheel turns to the right. The greater the steering wheel turns to the right, the stronger the user's intention to turn right. The stronger the user's intention to turn right, the greater the braking force output to the two right wheels. This avoids wheel locking due to insufficient drive compensation that affects the normal driving of the vehicle, thereby improving the driving experience.

[0035] In an implementation of the first aspect, the control method specifically includes: at a third moment, the steering wheel angle to the right increases to be greater than a first preset angle and the speed of the electric vehicle is a third speed, and the increase in the driving torque output by the drive system is controlled to be the first driving torque; at the third moment, the steering wheel angle to the right increases to be greater than the first preset angle and the speed of the electric vehicle is a fourth speed, and the increase in the driving torque output by the drive system is controlled to be the second driving torque; wherein the third speed is less than the fourth speed, and the first driving torque is greater than the second driving torque.

[0036] In some cases, when the braking force is output to the two right wheels, the greater the speed of the electric vehicle, the smaller the compensatory drive required to ensure that the electric vehicle does not stall, and the smaller the speed of the electric vehicle, the larger the compensatory drive required to ensure that the electric vehicle does not stall.

[0037] In this embodiment, when the steering wheel turning angle to the right increases to be greater than the first preset angle, when the speed of the electric vehicle is high, the increase in the driving torque output by the control drive system is smaller, that is, the compensatory drive is smaller, and when the speed of the electric vehicle is low, the increase in the driving torque output by the control drive system is larger, that is, the larger the compensatory drive is, to ensure that the electric vehicle does not stall due to the braking of the two right wheels by the braking system.

[0038] In an implementation of the first aspect, at the second moment, the electric vehicle travels at a speed greater than a preset speed.

[0039] In this embodiment, by setting a preset speed, the electric vehicle is prevented from stalling after the braking system outputs braking force to the two right wheels of the electric vehicle, thereby improving the driving experience.

[0040] In a second aspect, an embodiment of the present application provides a vehicle controller, which is used to execute a vehicle control method as in any implementation of the first aspect.

[0041] In an implementation of the second aspect, the vehicle control is used to receive a steering wheel angle signal and a vehicle speed signal. The steering wheel angle signal is used to indicate the angle of the steering wheel, and the angle indicated by the steering wheel angle signal is greater than a first preset angle at a second moment. The vehicle speed signal is used to indicate the speed of the electric vehicle, and the speed of the electric vehicle indicated by the speed signal is greater than a preset speed at a first moment.

[0042] In an implementation of the second aspect, the vehicle controller is used to output a torque instruction to the motor controller and a brake instruction to the brake controller at the second moment. The torque instruction is used to instruct the motor controller to control the drive motor of the electric vehicle to output a drive torque, and the brake instruction is used to instruct the wheel-end brake devices of the two right wheels of the electric vehicle to output a braking force to the two right wheels.

[0043] In a third aspect, an embodiment of the present application provides an electric vehicle, which includes a vehicle controller, a drive system, and a brake system as in the second aspect. The drive system includes a motor controller and a drive motor, and the motor controller is used to control the drive motor to output a drive torque to the wheels of the electric vehicle. The brake system includes a brake controller and four wheel-end brake devices, and the brake controller is used to control the four wheel-end brake devices to output a braking force to the four wheels of the electric vehicle.

[0044] As for the supplementary and technical effects of the solutions provided in the second and third aspects above, please refer to the corresponding description of the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a schematic diagram of an electric vehicle 100 provided in an embodiment of the present application;

[0046] Figure 2 is a schematic diagram of the architecture of an electric vehicle 100 provided in an embodiment of the present application;

[0047] Figure 3 is a schematic diagram of a control process of turning an electric vehicle provided in an embodiment of the present application;

[0048] Figure 4 is a schematic diagram of a vehicle controller of an electric vehicle 100 provided in an embodiment of the present application;

[0049] Figure 5 is a schematic diagram of another vehicle controller of an electric vehicle 100 provided in an embodiment of the present application;

[0050] Figure 6 is a flow chart of a method for controlling turning of an electric vehicle provided in an embodiment of the present application;

[0051] Figure 7 It is a schematic diagram of a scenario in which the electric vehicle 100 turns left according to an embodiment of the present application. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0053] The prefixes such as "first" and "second" used in the embodiments of the present application are only used to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers used to distinguish description objects in the embodiments of the present application does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and the use of such prefixes should not constitute an unnecessary limitation.

[0054] When an electric vehicle is traveling in a limited space, such as a narrow road, the large turning radius of the electric vehicle makes it difficult for the driver to accurately control the electric vehicle to quickly change the driving direction in the limited space, which increases the difficulty of turning the electric vehicle and affects the user's driving experience.

[0055] Moreover, if emergency avoidance is required during driving and the straight-line distance is not enough to brake the vehicle, if the turning radius of the electric vehicle is large and the maneuverability of the electric vehicle is poor, it is difficult for the driver to accurately control the electric vehicle to quickly change the driving direction and achieve emergency obstacle avoidance.

[0056] In view of this, an embodiment of the present application provides a control method for turning an electric vehicle, a vehicle controller and an electric vehicle. By coordinating the control of the driving system and the braking system of the electric vehicle, the turning radius of the electric vehicle can be reduced and the driving direction can be quickly changed during the turning process.

[0057] See also Figure 1 , Figure 1 Schematic diagram of an electric vehicle 100 provided in an embodiment of the present application. Figure 1 As shown, the electric vehicle 100 includes a drive system 110, a power battery 120 connected to the drive system 110, and a vehicle controller 130. The drive system 110 is used to drive the electric vehicle 100. The power battery 120 is used to provide electrical energy to the drive system 110. The drive system 110 is used to receive power from the power battery 120 and provide power to the electric vehicle 100. The vehicle controller 130 is used to control the drive system 110.

[0058] In one embodiment, the electric vehicle 100 further includes a braking system 140, and the braking system 140 is used to provide braking force for the electric vehicle 100 when the electric vehicle 100 is in a braking state. The drive system 110 may also be referred to as a powertrain.

[0059] According to the position of the wheels in the electric vehicle 100, they can be divided into a left front wheel FL, a right front wheel FR, a left rear wheel BL, and a right rear wheel BR. According to the axle, the left front wheel and the right front wheel are coaxial and connected by the front axle. The left rear wheel and the right rear wheel are coaxial and connected by the rear axle. According to the position, the left front wheel and the left rear wheel are on the same side and located on the left side, and the right front wheel and the right rear wheel are on the same side and located on the right side. That is to say, among the four wheels of the electric vehicle 100, the left front wheel and the right front wheel are coaxial wheels with each other, and the left rear wheel and the right rear wheel are coaxial wheels with each other; the left front wheel and the left rear wheel are wheels on the same side, and the right front wheel and the right rear wheel are wheels on the same side.

[0060] The electric vehicle 100 in the embodiment of the present application can be any one of different types of vehicles such as a sedan, 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, the vehicle includes but is not limited to a pure electric vehicle (pure electric vehicle / battery electric vehicle, pure EV / batteryEV), a hybrid electric vehicle (hybrid electric vehicle, HEV), a range extended electric vehicle (range extended electric vehicle, REEV), a plug-in hybrid electric vehicle (plug-in hybrid electric vehicle, PHEV), a new energy vehicle (new energy vehicle, NEV), etc.

[0061] The embodiment of the present application does not limit the specific type of the powertrain. As an example and not a limitation, the powertrain can be a centralized powertrain, a hub motor powertrain, or a wheel-side motor powertrain. Among them, the hub motor powertrain is to directly set the motor and the reducer in the wheel rim, eliminating the transmission components such as the half shaft, universal joint, differential, and transmission; the wheel-side motor powertrain is to set the motor on the subframe.

[0062] The power battery 120 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., which is not limited in the present application. In terms of scale, the power battery 120 in the embodiment of the present application can be a single cell, or a battery module or a battery pack, which is not limited in the present application. The power battery 120 can also power other electrical devices in the vehicle, such as the air conditioner in the vehicle, the car player, etc.

[0063] Figure 2 A schematic diagram of the architecture of an electric vehicle 100 provided in an embodiment of the present application is shown.

[0064] See also Figure 2 (a) The electric vehicle 100 is a two-wheel drive vehicle, and the driving system 110 includes a driving motor 111 for two front wheels and a motor controller 121 for the driving motor 111 , and a driving motor 112 for two rear wheels and a motor controller 122 for the driving motor 112 .

[0065] When the electric vehicle 100 is in a driving state, each drive motor in the drive system 110 is used to provide driving force for the electric vehicle 100. Specifically, when the electric vehicle 100 is in a driving state, the vehicle controller 130 outputs a torque signal to the motor controller of each drive motor, and each motor controller receives electric energy from the power battery 120 and controls the corresponding drive motor to output the torque indicated by the torque signal.

[0066] Continue to refer Figure 2 (a) in the figure, the braking system 140 mainly includes a brake pedal ( Figure 2 (a) (not shown), a brake controller 141 and four wheel-end brake devices 142. Among them, the brake controller 141 can control one or more of the four wheel-end brake devices 142 to output braking force to the corresponding wheel to prevent the wheel from rotating or preventing the wheel from rotating. Further, during the braking process of the electric vehicle 100, the greater the braking force indicated by the braking signal, the greater the braking force output by the wheel-end brake device 142, and the faster the speed of the electric vehicle 100 decreases.

[0067] The brake in the braking system 140 in the embodiment of the present application may be an electronic hydraulic brake (EHB) or an electronic mechanical brake (EMB) or other types of brakes without limitation.

[0068] When the electric vehicle 100 is in a braking state, the braking system 140 provides braking force to the wheels so that the electric vehicle 100 reduces its speed under the action of the braking force. In the braking state of the electric vehicle 100, each drive motor in the electric vehicle 100 with an energy recovery function can also be used to provide braking force for the electric vehicle 100. Specifically, when the electric vehicle 100 is in a braking state, the vehicle controller 130 receives a braking signal and sends an energy recovery instruction to each motor controller. Each motor controller controls the corresponding drive motor to operate in a power generation state in response to the energy recovery instruction. Each drive motor converts the kinetic energy of the wheels of the electric vehicle into electrical energy and outputs a negative torque to the wheels of the electric vehicle 100 to provide braking force to the electric vehicle 100.

[0069] Among them, the drive system 110, the brake system 140 and the vehicle controller 130 are communicatively connected via a CAN network, and the embodiments of the present application do not limit the specific communication connection method. For example, the motor controller in the drive system 110 and the vehicle controller 130 can communicate through a private CAN network, the brake controller 141 of the brake system 140 and the vehicle controller 130 can communicate through a public CAN network, and the brake controller 141 and each wheel-end brake device 142 can communicate through another private CAN network. For another example, the vehicle controller 130 can communicate with the motor controller in the drive system 110 and the brake controller 141 in the brake system 140 through the same CAN network.

[0070] In one embodiment, the vehicle controller 130 can also obtain a driving mode signal through the CAN network, and the driving mode signal is used to indicate the current driving mode of the electric vehicle 100. For example, the driving mode may include one or more of a sports mode, a comfort mode, and an intelligent mode.

[0071] In one embodiment, the vehicle controller 130 can also obtain a vehicle gear signal through the CAN network, and the vehicle gear signal is used to indicate the current gear of the electric vehicle 100. For example, the gear may include a forward gear, a reverse gear, etc.

[0072] See also Figure 2 (b) The electric vehicle 100 is a four-wheel drive vehicle, and the drive system 110 includes a drive motor 113 for the left front wheel and a motor controller 123 for the drive motor 113, a drive motor 114 for the right front wheel and a motor controller 124 for the drive motor 114, a drive motor 115 for the left rear wheel and a motor controller 125 for the drive motor 115, and a drive motor 116 for the right rear wheel and a motor controller 126 for the drive motor 116.

[0073] The magnitude and / or direction of the driving torque output by the driving system to the four wheels may be the same or different. The magnitude and / or direction of the driving torque output by the braking system to the four wheels may be the same or different.

[0074] The above describes the architecture of the embodiment of the present application. The following describes the electric vehicle turning control method provided by the present application in combination with a specific embodiment. The electric vehicle turning control method provided by the embodiment of the present application is used to control the braking system and driving system of the electric vehicle to reduce the turning radius of the electric vehicle during the turning process of the electric vehicle.

[0075] In one embodiment, the control method includes: at a first moment, the right turning angle of the steering wheel of the electric vehicle increases from zero, and the two front wheels of the electric vehicle are controlled to turn right; at a second moment after the first moment, the right turning angle of the steering wheel of the electric vehicle increases to be greater than a first preset angle, and in the process of controlling the drive system to output driving torque to the electric vehicle to drive the electric vehicle, the braking system of the electric vehicle is controlled to output braking force to the two right wheels of the electric vehicle.

[0076] The above control method achieves the goal of reducing the turning radius of the electric vehicle when the electric vehicle turns right. Similar to the electric vehicle turning right, when the electric vehicle turns left, the control method includes: at a first moment, the left turning angle of the steering wheel of the electric vehicle increases from zero, and the two front wheels of the electric vehicle are controlled to turn left; at a second moment after the first moment, the left turning angle of the steering wheel of the electric vehicle increases to be greater than a first preset angle, and in the process of controlling the drive system to output driving torque to the electric vehicle to drive the electric vehicle, the braking system of the electric vehicle is controlled to output braking force to the two left wheels of the electric vehicle.

[0077] The electric vehicle turning control method provided in the embodiment of the present application can be applied to realize electric vehicle turning in various vehicle driving scenarios, such as vehicle parking scenarios, vehicle driving on the road scenarios, etc.

[0078] In the electric vehicle turning control method provided in the embodiment of the present application, through the aforementioned coordinated control of the drive system and the braking system, it is possible to reduce the turning radius of the electric vehicle and quickly change the driving direction during the turning process, thereby reducing the difficulty of the electric vehicle turning in a limited space and improving the maneuverability and driving experience of the electric vehicle.

[0079] In the electric vehicle turning control method provided in the embodiment of the present application, the process of controlling the braking system and drive system of the electric vehicle to reduce the turning radius of the electric vehicle during the electric vehicle turning right is described in detail. Controlling the braking system and drive system of the electric vehicle to reduce the turning radius of the electric vehicle during the electric vehicle turning left is the opposite side of the process described in the embodiment of the present application and will not be repeated here.

[0080] In order to facilitate understanding of the electric vehicle turning control method provided in the embodiment of the present application, Figure 3 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 and the control method for turning the electric vehicle provided in the embodiment of the present application are described. In the embodiment of the present application, the control method may include the following operations.

[0081] At the first moment t1, the rightward turning angle of the steering wheel of the electric vehicle starts to increase from zero, and the two front wheels of the electric vehicle are controlled to turn right. In one embodiment, at the first moment t1, the user starts to turn the steering wheel, and the two front wheels of the electric vehicle start to turn right. At this time, the electric vehicle can be in a stationary state or in a driving state, and there is no restriction on this. Figure 3 The electric vehicle shown as an example in FIG. 1 is in a driving state.

[0082] At a second moment t2 after the first moment t1, the rightward turning angle of the steering wheel of the electric vehicle increases to be greater than the first preset angle (which can be represented by R1). The embodiment of the present application does not limit the specific value of the first preset angle, and the first preset angle can be a larger preset angle, such as 70 degrees, 80 degrees, 90 degrees, etc. When the rightward turning angle of the steering wheel increases to be greater than the first preset angle, it can be considered that the electric vehicle needs to complete the right turn.

[0083] At the second moment t2, the drive system is controlled to output a drive torque to the electric vehicle to drive the electric vehicle. At the second moment t2, in the process of controlling the drive system to output a drive torque to the electric vehicle to drive the electric vehicle, the brake system of the electric vehicle is also controlled to output a braking force to the two right wheels of the electric vehicle. In the embodiment of the present application, at the second moment t2, the drive system is controlled to output a drive torque to the electric vehicle so as to control the electric vehicle to be in a driving state, and the brake system is controlled while the electric vehicle is in a driving state, so as to avoid the brake system outputting a braking force to the two right wheels of the electric vehicle when the electric vehicle is in a stationary state, causing the electric vehicle to be jerked, thereby ensuring the driving experience.

[0084] Among them, controlling the drive system to output drive torque to the electric vehicle means controlling the drive system to output drive torque to the wheels of the electric vehicle, which may be outputting drive torque to four wheels or outputting drive torque to some of the wheels, such as two.

[0085] In one embodiment, during the driving of the electric vehicle, the braking system of the electric vehicle outputs braking force to the two right wheels, the wheel speeds of the two right wheels begin to decrease, and the wheel speeds of the two left wheels remain unchanged.

[0086] In an embodiment of the present application, without controlling the braking system to output braking force to the two right wheels of the electric vehicle, during the turning process of the electric vehicle, the lateral force that the two wheels on the outside of the turn need to bear is greater than the lateral force that the two wheels on the inside of the turn need to bear, and the difference between the lateral force of the two wheels on the outside of the turn and the lateral force of the two wheels on the inside of the turn will generate a yaw moment, which determines the turning radius of the electric vehicle.

[0087] In the embodiment of the present application, at the second moment t2, by outputting a braking force to the two right wheels of the electric vehicle, the braking force will generate an additional yaw moment.

[0088] In this embodiment, in the scenario of controlling the turning of an electric vehicle, by setting a first preset angle, after the user turns the steering wheel to the right to an angle greater than the first preset angle, the drive system and the brake system of the electric vehicle are coordinated to control the vehicle to complete the turn. The coordinated control of the drive system and the brake system of the electric vehicle includes, in the process of the drive system driving the electric vehicle to drive, controlling the brake system of the electric vehicle to output a braking force to the two wheels on the inner side of the turn of the electric vehicle, and the braking force will provide an additional yaw moment to increase the yaw moment of the electric vehicle, and the increase in the yaw moment increases the yaw angular velocity of the electric vehicle, and the increase in the yaw angular velocity causes the vehicle to change the driving direction faster and the turning center of the electric vehicle moves to the inner side of the turn, thereby reducing the turning radius. In this way, the aforementioned coordinated control of the drive system and the brake system can reduce the turning radius of the electric vehicle and quickly change the driving direction during the turning process, reduce the difficulty of the electric vehicle turning in a limited space, and improve the maneuverability and driving experience of the electric vehicle.

[0089] When the braking force output to the two right wheels is too large, the wheels may lock, affecting the normal driving of the vehicle. Therefore, in one embodiment, at the second moment, the braking force output by the braking system to the two right wheels is less than the braking force threshold.

[0090] The braking force threshold F is determined according to the friction coefficient of the road surface on which the electric vehicle is traveling. The greater the friction coefficient, the greater the braking force threshold.

[0091] In this embodiment, by setting the braking force threshold, excessive braking force output to the two right wheels is avoided to cause wheel locking, thereby ensuring normal driving of the vehicle.

[0092] In one embodiment, at the second time t2, the electric vehicle travels at a speed greater than a preset speed.

[0093] The preset speed V may be a relatively small value, such as 5 kph, 10 kph, 50 kph, etc. It can be considered that when the electric vehicle travels at a speed greater than the preset speed, the braking system outputs braking force to the two right wheels of the electric vehicle without causing the electric vehicle to stall. The specific value of the preset speed is not limited in the present embodiment.

[0094] In this embodiment, by setting a preset speed, the electric vehicle is prevented from stalling after the braking system outputs braking force to the two right wheels of the electric vehicle, thereby improving the driving experience.

[0095] In some cases, the electric vehicle will generate centrifugal force during the turning process, which will cause the electric vehicle to slide outward. The greater the speed of the electric vehicle, the greater the centrifugal force of the electric vehicle, and the stronger the tendency of the electric vehicle to slide outward. If the tendency of the electric vehicle to slide outward cannot be overcome, it will be difficult for the electric vehicle to complete the turn in the desired direction, it will be difficult to reduce the turning radius, and there may be instability such as side slipping.

[0096] Thus, in one embodiment, the control method further includes: at a second moment t2, the steering wheel angle to the right increases to be greater than a first preset angle and the speed of the electric vehicle is a first speed, and the braking system is controlled to output a first braking force to the two right wheels; at a second moment, the steering wheel angle to the right increases to be greater than the first preset angle and the speed of the electric vehicle is a second speed, and the braking system is controlled to output a second braking force to the two right wheels; wherein, the first speed is less than the second speed, and the first braking force is less than the second braking force.

[0097] The first vehicle speed V1 and the second vehicle speed V2 are both greater than the preset vehicle speed V. The embodiment of the present application does not limit the specific values ​​of the first vehicle speed, the second vehicle speed, the first braking force F1 and the second braking force F2.

[0098] In this embodiment, when the steering wheel turning angle to the right increases to be greater than the first preset angle, the braking force output by the braking system is controlled to be larger when the speed of the electric vehicle is larger so that the centrifugal force is larger, and the braking force output by the braking system is controlled to be smaller when the speed of the electric vehicle is smaller so that the centrifugal force is smaller. This allows the component of the braking force in the lateral direction to balance the centrifugal force, overcome the tendency of the electric vehicle to slide outward, avoid unstable phenomena such as side slipping, and provide sufficient yaw torque for the electric vehicle at different speeds, thereby ensuring that the electric vehicle successfully turns right while reducing the turning radius of the electric vehicle.

[0099] In some cases, during a turn of the electric vehicle, the greater the rightward turn of the steering wheel, the stronger the user's intention to turn right.

[0100] Thus, in one embodiment, the control method further comprises: at the second moment t2, the rightward turning angle of the steering wheel increases to be greater than the first angle and the speed of the electric vehicle is greater than the preset speed, controlling the braking system to output the third braking force to the two right wheels; or, at the second moment t2, the rightward turning angle of the steering wheel increases to be greater than the second angle and the speed of the electric vehicle is greater than the preset speed, controlling the braking system to output the fourth braking force to the two right wheels. Wherein, the first angle is smaller than the second angle, and the third braking force is smaller than the fourth braking force.

[0101] The embodiment of the present application does not limit the specific values ​​of the first angle, the second angle, the third braking force and the fourth braking force. In one embodiment, the first angle and the second angle are both greater than the first preset angle.

[0102] In this embodiment, when the speed of the electric vehicle is greater than a preset speed, when the steering wheel is turned to the right at a larger angle, that is, when the user's intention to turn right is stronger, the braking force output by the braking system is controlled to be larger; when the steering wheel is turned to the right at a smaller angle, that is, when the user's intention to turn right is not strong enough, the braking force output by the braking system is controlled to be smaller, so that the braking force output by the braking system matches the user's intention to turn right, thereby improving the driving experience.

[0103] In some cases, if the braking force output by the braking system is too large, it may cause the wheels to lock and the electric vehicle to stall, affecting the normal driving of the vehicle.

[0104] In one embodiment, the control method further includes: at a third moment t3 after the second moment t2, in the process of controlling the braking system to output braking force to the two right wheels, controlling the driving torque output by the driving system to the electric vehicle to increase.

[0105] Among them, in the process of controlling the braking system to output braking force to the two right wheels, the purpose of controlling the drive system to increase the driving torque output to the electric vehicle is to compensate for the drive of the electric vehicle and ensure that the electric vehicle does not stall due to the braking of the two right wheels by the braking system.

[0106] Among them, the driving torque output by the drive system to the electric vehicle is determined by the opening of the brake pedal or the automatic driving system, and the increase in the driving torque output to the electric vehicle is determined by the braking system.

[0107] Among them, controlling the driving torque output by the drive system to the electric vehicle to increase means controlling the driving torque output by the drive system to at least one wheel of the electric vehicle to increase, and for two-wheel drive, three-wheel drive and four-wheel drive electric vehicles, the number of wheels whose driving torque is increased is different.

[0108] For two-wheel drive electric vehicles, the two front wheels of the electric vehicle are driven by the same drive motor, and the two rear wheels are driven by the same drive motor. It is impossible to individually control the drive system to increase the drive torque output to the two left wheels. Therefore, the drive system is controlled to increase the drive torque output to the four wheels.

[0109] For three-wheel drive electric vehicles, the two front wheels of the electric vehicle are driven by the same drive motor, and the two rear wheels are driven by different drive motors. It is impossible to control the drive system to increase the drive torque output to the left front wheel alone, so the drive system is controlled to increase the drive torque output to the two front wheels and the left rear wheel. Similarly, when the two front wheels of the electric vehicle are driven by different drive motors and the two rear wheels are driven by the same drive motor, the drive system is also controlled to increase the drive torque output to the three wheels.

[0110] For four-wheel drive electric vehicles, the drive system can independently control the drive torque to the four wheels, so the drive torque output to the two left wheels is increased. In this process, the four wheels of the electric vehicle are independently controlled, which can ensure that each wheel works in a more efficient and stable range, avoiding the control effect affected by a wheel entering a nonlinear area.

[0111] Among them, the driving torque output by the drive system to the electric vehicle is increased to a maximum value when its component in the forward direction of the electric vehicle is equal to the component of the braking force output to the two right wheels in the forward direction, so as to ensure that the turning radius of the electric vehicle is reduced during the turning process of the electric vehicle while the vehicle speed is in a stable state, thereby improving the driving experience.

[0112] In this embodiment, in the process of controlling the braking system to output braking force to the two right wheels, the driving torque output by the control drive system to the electric vehicle is increased to compensate for the drive of the electric vehicle, so that the electric vehicle avoids stalling due to the braking of the two right wheels by the braking system. In this way, while ensuring the normal driving of the electric vehicle, the turning radius of the electric vehicle is reduced by the yaw torque provided by the braking force.

[0113] In some cases, when the braking force is output to the two right wheels, the greater the speed of the electric vehicle, the smaller the compensatory drive required to ensure that the electric vehicle does not stall, and the smaller the speed of the electric vehicle, the larger the compensatory drive required to ensure that the electric vehicle does not stall.

[0114] In one embodiment, the control method further includes: at the third moment t3, the rightward turning angle of the steering wheel increases to be greater than the first preset angle and the speed of the electric vehicle is the third speed, and the increase in the driving torque output by the drive system to at least one wheel is the first driving torque; or, at the third moment t3, the rightward turning angle of the steering wheel increases to be greater than the first preset angle and the speed of the electric vehicle is the fourth speed, and the increase in the driving torque output by the drive system to at least one wheel is the second driving torque. Wherein, the third speed is less than the fourth speed, and the first driving torque is greater than the second driving torque.

[0115] The embodiment of the present application does not limit the specific values ​​of the third vehicle speed, the fourth vehicle speed, the first driving torque and the second driving torque. In one embodiment, the third vehicle speed V3 and the fourth vehicle speed V4 are both greater than the preset vehicle speed V.

[0116] In this embodiment, when the steering wheel turning angle to the right increases to be greater than the first preset angle, when the speed of the electric vehicle is high, the increase in the driving torque output by the control drive system is smaller, that is, the compensatory drive is smaller, and when the speed of the electric vehicle is low, the increase in the driving torque output by the control drive system is larger, that is, the larger the compensatory drive is, to ensure that the electric vehicle does not stall due to the braking of the two right wheels by the braking system.

[0117] When the driving torque output to at least one wheel increases too much, the wheel may slip, affecting the normal driving of the vehicle. Therefore, in one embodiment, at the third moment, the driving torque output by the driving system to the electric vehicle is controlled to increase to less than the driving torque threshold.

[0118] The driving torque threshold T is determined according to the friction coefficient of the road surface on which the electric vehicle is traveling. The greater the friction coefficient, the greater the driving torque threshold.

[0119] In this embodiment, by setting the driving torque threshold, excessive braking force output to the two right wheels is avoided to cause wheel slippage, thereby ensuring normal driving of the vehicle.

[0120] In one embodiment, the control method further includes: at a fourth moment t4 after the third moment t3, the rightward turning angle of the steering wheel decreases to less than a second preset angle, and the braking system is controlled to stop outputting braking force to the two right wheels.

[0121] In one embodiment, at the fourth moment t4, the electric vehicle is about to complete a right turn or has completed a right turn, and the user begins to straighten the steering wheel. When the steering wheel angle to the right decreases to less than a second preset angle R2, the electric vehicle resumes normal driving, that is, the braking system is controlled to stop outputting braking force to the two right wheels.

[0122] The second preset angle is a smaller preset angle, such as 5 degrees, 10 degrees, 15 degrees, etc. When the rightward turning angle of the steering wheel decreases to less than the second preset angle, it can be considered that the electric vehicle has completed the right turn or is about to complete the right turn. The embodiment of the present application does not limit the specific value of the second preset angle.

[0123] In this embodiment, by detecting that the steering wheel turning angle to the right is reduced to less than a second preset angle, it is possible to automatically detect that the electric vehicle has completed a turn or is about to complete a turn, and at this time, the braking system is automatically controlled to stop outputting braking force to the two right wheels to ensure that the electric vehicle can drive normally after completing the turn.

[0124] At the same time, by setting the second preset angle, the user is prevented from accidentally touching the steering wheel while the electric vehicle has not actually completed the right turn or is about to complete the right turn, causing the control braking system to stop outputting braking force to the two right wheels, affecting the electric vehicle's turning radius during the right turn, affecting the electric vehicle's safe turning when the driving space is small, and thus affecting the maneuverability of the electric vehicle.

[0125] By controlling the driving system and braking system of the electric vehicle between the first moment t1 and the fourth moment t4, the electric vehicle is controlled to turn right, and by controlling the driving system and braking system of the electric vehicle between the second moment t2 and the fourth moment t4, the turning radius of the electric vehicle is reduced in the process of controlling the electric vehicle to turn right.

[0126] The following will describe in detail the process of controlling the driving torque output by the driving system and the braking force output by the braking system of the electric vehicle between the second time t2 and the fourth time t4.

[0127] In some cases, the electric vehicle will generate centrifugal force during the turning process, which will cause the electric vehicle to slide outward. The greater the speed of the electric vehicle, the greater the centrifugal force of the electric vehicle, and the stronger the tendency of the electric vehicle to slide outward. If the tendency of the electric vehicle to slide outward cannot be overcome, the electric vehicle will not be able to complete the turn in the desired direction, the turning radius cannot be reduced, and it is very likely to experience unstable phenomena such as side slipping.

[0128] Thus, in one embodiment, the control method further comprises: between the second moment t2 and the fourth moment t4, controlling the braking system to increase the braking force output to the two right wheels as the speed of the electric vehicle increases.

[0129] In one embodiment, between the second moment t2 and the fourth moment t4, the speed of the electric vehicle is always greater than the preset speed, which can ensure the stability of the vehicle during the turning process and improve the driving experience.

[0130] In this embodiment, the braking force output by the braking system to the two right wheels is increased as the speed of the electric vehicle increases, so that when the electric vehicle is turning, when the centrifugal force changes with the speed of the vehicle, the braking force can be flexibly adjusted according to the speed, so that the component of the braking force in the lateral direction can balance the centrifugal force, overcome the tendency of the electric vehicle to slide outward, avoid unstable phenomena such as side slip, and provide sufficient yaw torque for the electric vehicle at different speeds, ensuring that the electric vehicle successfully turns right while reducing the turning radius of the electric vehicle.

[0131] In some cases, during a turn of the electric vehicle, the greater the rightward turn of the steering wheel, the stronger the user's intention to turn right.

[0132] Thus, in one embodiment, the control method further comprises: between the second moment t2 and the fourth moment t4, controlling the braking system to increase the braking force output to the two right wheels as the steering wheel turns to the right.

[0133] In this embodiment, the braking force output to the two right wheels by controlling the braking system increases as the steering wheel turns to the right. The greater the steering wheel turns to the right, the greater the braking force. The greater the braking force, the greater the yaw moment provided. The greater the yaw moment, the faster the electric vehicle changes its direction of travel and the smaller the turning radius, which can match the user's stronger intention to turn right and improve the driving experience.

[0134] In some cases, when the electric vehicle turns right, the vertical load on the right front wheel is greater than the vertical load on the right rear wheel, so that the maximum yaw moment that can be generated by the right front wheel is greater than the maximum yaw moment that can be generated by the right rear wheel.

[0135] Thus, in one embodiment, the control method further includes: between the second moment t2 and the fourth moment t4, controlling the braking system of the electric vehicle to output a braking force to the right front wheel that is greater than the braking force output to the right rear wheel.

[0136] In this embodiment, the braking force output to the right front wheel by the braking system of the electric vehicle is greater than the braking force output to the right rear wheel, so as to match the yaw moment provided by the braking force of the right front wheel during the turning process of the electric vehicle, which is greater than the yaw moment provided by the braking force of the right rear wheel, thereby avoiding unreasonable braking force output to the right front wheel or the right rear wheel, which may cause the electric vehicle to lose control and tire damage.

[0137] In some cases, in a two-wheel drive or three-wheel drive electric vehicle, the drive system of the electric vehicle cannot output drive torque to a certain wheel alone, and according to the above-mentioned implementation method, the braking force output by the braking system to the right front wheel and the right rear wheel is different.

[0138] Thus, in one embodiment, the control method further includes: between the third moment t3 and the fourth moment t4, controlling the driving torque output by the drive system to the two front wheels of the electric vehicle to increase as the braking force output by the braking system to the right front wheel increases, or controlling the driving torque output by the drive system to the two rear wheels of the electric vehicle to increase as the braking force output by the braking system to the right rear wheel increases.

[0139] In this embodiment, the driving torque output by the drive system to the two front wheels is associated with the braking force output by the brake system to the right front wheel, so that the driving torque output to the two front wheels increases with the increase of the braking force output to the right front wheel, and the driving torque output by the drive system to the two rear wheels is associated with the braking force output by the brake system to the right rear wheel, so that the driving torque output to the two rear wheels increases with the increase of the braking force output to the right rear wheel. This avoids the wheel locking caused by the excessive braking force without sufficient compensation for the drive, which affects the normal driving of the vehicle, and ensures that the electric vehicle does not stall due to the braking of the two right wheels by the brake system.

[0140] In some cases, the greater the steering wheel turns to the right, the stronger the user's intention to turn right. The stronger the user's intention to turn right, the greater the braking force. Without compensatory drive, the wheels may lock, affecting the normal driving of the vehicle.

[0141] Thus, in one embodiment, the control method further includes: between the third moment t3 and the fourth moment t4, controlling the increase in the driving torque output by the driving system to at least one wheel to increase as the steering wheel turns to the right.

[0142] In this embodiment, the increase in the driving torque output by the drive system to at least one wheel increases as the steering wheel turns to the right. The greater the steering wheel turns to the right, the stronger the user's intention to turn right. The stronger the user's intention to turn right, the greater the braking force output to the two right wheels, thereby avoiding wheel locking due to insufficient compensation for drive and affecting normal vehicle driving, thereby improving the driving experience.

[0143] Combine the following Figures 3 to 5 The vehicle controller provided in the embodiment of the present application is described in detail. Figure 4 and Figure 5 A schematic diagram of a vehicle controller of an electric vehicle 100 is shown. The vehicle controller provided in the embodiment of the present application is used to execute the control method provided in the above embodiment. The specific principle of the vehicle controller executing the control method provided in the above embodiment is described below in conjunction with a specific embodiment.

[0144] See also Figure 4 , when the user turns the steering wheel to the right, Figure 4As shown, the vehicle controller receives steering wheel angle signals, inertial measurement unit IMU signals, wheel speed signals and vehicle speed signals from other controllers or sensors. If the steering wheel angle signal indicates that the steering wheel angle to the right is greater than a first preset angle and the calculated vehicle speed is greater than the preset vehicle speed, the vehicle controller calculates the braking force output to the two right wheels of the electric vehicle based on the input signal, and sends a braking command to the brake controller so that the brake controller controls the wheel-end braking device to output braking force to brake the two wheels.

[0145] Among them, the steering wheel angle signal indicates the steering wheel angle to the right, the IMU signal indicates the acceleration and angular velocity of the three coordinate axes xyz, the wheel speed signal indicates the wheel speed, the vehicle speed signal indicates the vehicle speed, and the braking command indicates the braking force output to the two right wheels.

[0146] In one embodiment, the vehicle controller includes a braking force calculation module for calculating the braking force output by the braking system to the two right wheels, and the braking force calculation module is used to: determine the yaw moment provided by the braking force at the right steering angle indicated by the steering wheel angle signal and the vehicle speed indicated by the vehicle speed signal based on a pre-constructed first mapping relationship; distribute the yaw moment to the two right wheels of the electric vehicle to obtain the braking force output by the braking system to the right front wheel and the braking force output to the right rear wheel.

[0147] The first mapping relationship is the relationship between the yaw moment provided by the braking force and the rightward turning angle of the steering wheel and the speed of the electric vehicle. The yaw moment provided by the braking force and the rightward turning angle of the steering wheel and the speed of the electric vehicle are all positively correlated.

[0148] In one embodiment, the braking force calculation module is specifically used to: calculate the vertical load of the right front wheel and the vertical load of the right rear wheel according to the acceleration and angular velocity of the three coordinate axes xyz indicated by the IMU signal, the weight of the electric vehicle and the wheel speed indicated by the wheel speed signal; calculate the maximum longitudinal force of the right rear wheel and the maximum longitudinal force of the right front wheel according to the vertical load of the right front wheel, the vertical load of the right rear wheel and the friction coefficient; calculate the maximum yaw moment of the right rear wheel and the maximum yaw moment of the right front wheel according to the maximum longitudinal force of the right rear wheel and the maximum longitudinal force of the right front wheel; distribute the yaw moment provided by the braking force to the right rear wheel and the right front wheel according to the maximum yaw moment of the right rear wheel and the maximum yaw moment of the right front wheel, and convert the yaw moment distributed to the right rear wheel and the right front wheel into the braking force output by the braking system to the right front wheel and the braking force output to the right rear wheel.

[0149] In this embodiment, the yaw moment provided by the braking force required for the electric vehicle to turn right is distributed to the right front wheel and the right rear wheel according to the maximum yaw moment of the right front wheel and the left front wheel, and the yaw moment is converted into braking force, thereby obtaining the braking force output to the right front wheel and the right rear wheel, thereby avoiding unreasonable braking force output to the right front wheel or the right rear wheel, which may cause the electric vehicle to lose control and tire damage.

[0150] For any wheel i of the two right wheels, the maximum longitudinal force F i =μN i , μ is the friction coefficient, N i is the vertical load of wheel i. Generally, during the turning process of an electric vehicle, the vertical load of the front wheel is greater than that of the rear wheel.

[0151] The maximum yaw moment M of wheel i i = l i F i , l i is the distance from wheel i to the center of mass of the electric vehicle.

[0152] Assume that the yaw moment provided by the braking force is M, the maximum yaw moment of the right front wheel is M1, and the maximum yaw moment of the right rear wheel is M2. If M1:M2=3:2, then the yaw moment provided by the braking force output to the right front wheel is M1′=3 / 5M, and the yaw moment provided by the braking force output to the right rear wheel is M2′=2 / 5M. The braking force output by the braking system to the right front wheel is M1′ / l1, and the braking force output to the right rear wheel is M1′ / l2.

[0153] If the brake of the electric vehicle is EMB, it is necessary to further convert the braking force output by the braking system to the right front wheel and the right rear wheel into the braking torque output by the brake motor. Usually, the braking torque = braking force × the rolling radius of the wheel.

[0154] In one embodiment, in combination Figure 3 and Figure 4 At the first moment t1, the rightward turning angle of the steering wheel of the electric vehicle increases from zero, so that the two front wheels of the electric vehicle turn right. At the second moment t2 after the first moment t1, the rightward turning angle of the steering wheel of the electric vehicle increases to be greater than the first preset angle (which can be represented by R1). At this time, the steering wheel angle indicated by the steering wheel angle signal is greater than the first preset angle. The vehicle controller receives the steering wheel angle signal indicating that the steering wheel angle is greater than the first preset angle and receives the vehicle speed signal indicating that the vehicle speed is greater than the preset vehicle speed. At this time, the vehicle controller sends a braking command to the brake controller. In response to the braking command, the brake controller controls the wheel end brake devices corresponding to the two right wheels to output braking force to the two right wheels.

[0155] like Figure 4As shown, when the vehicle controller sends a braking command to the brake controller, the vehicle controller calculates the increase in driving torque according to the braking force output to the two right wheels as needed, and outputs a driving torque compensation command to the motor controller of at least one wheel according to the increase in driving torque to control the driving motor of at least one wheel to drive at least one wheel.

[0156] In one embodiment, the vehicle controller includes a driving torque increase calculation module for calculating the increase in driving torque output by the drive system to at least one wheel. The driving torque increase calculation module is used to: for each wheel, construct an equation based on the component of the braking force of the wheel in the forward direction and the component of the driving force after the driving torque output by the drive system is increased; by executing the calculation of the equation, the increase in driving torque output by the drive system to at least one wheel can be calculated.

[0157] If it is difficult to achieve the calculated increase in the driving torque output to at least one wheel, it is necessary to ensure that the increase in the driving torque output to at least one wheel is a calculated value of a specified percentage.

[0158] In other embodiments, the drive torque increase calculation module is further used to determine the drive torque increase at the right steering wheel angle indicated by the steering wheel angle signal and the vehicle speed indicated by the vehicle speed signal according to a pre-constructed second mapping relationship.

[0159] The second mapping relationship is the relationship between the increase in the driving torque and the rightward turning angle of the steering wheel and the speed of the electric vehicle. The increase in the driving torque is positively correlated with the rightward turning angle of the steering wheel, and the increase in the driving torque at medium and low vehicle speeds is greater than the increase in the driving torque at high vehicle speeds.

[0160] In this embodiment, the increase in the driving torque that needs to be output to the electric vehicle is determined based on the braking force output by the braking system, and the electric vehicle is compensated for the drive based on the increase to avoid wheel locking due to insufficient compensation for excessive braking force, which affects the normal driving of the vehicle, thereby ensuring that the electric vehicle does not stall due to the braking of the two right wheels by the braking system.

[0161] In one embodiment, in combination Figure 3 and Figure 4 At a third time t3 after the second time, the vehicle controller sends a driving torque compensation command to the motor controller. The motor controller controls the corresponding driving motor to output the driving torque in response to the driving torque compensation command.

[0162] In one embodiment, the vehicle controller provided in the embodiment of the present application is a whole vehicle controller.

[0163] In one embodiment, if Figure 5As shown, the vehicle controller provided in the embodiment of the present application is a motor controller. That is to say, the motor controller can directly receive the steering wheel angle signal, the inertial measurement unit IMU signal, the wheel speed signal and the vehicle speed signal to control the drive motor to output the corresponding compensation torque and output the braking command to the brake controller. By integrating the above control method into the motor controller, the signal link can be shortened and the control speed and control accuracy can be improved.

[0164] Figure 6 An example of a control method for turning an electric vehicle is given.

[0165] See also Figure 6 , Figure 6 A flow chart of a control method for turning an electric vehicle provided in an embodiment of the present application is shown, and the control method is used to control the electric vehicle to turn left. The control method may include the following steps:

[0166] S510: Determine whether an enable signal is detected.

[0167] The enabling signal here refers to a signal that enables the vehicle to turn left, and may be an indicator light signal generated by a user operating a left indicator light.

[0168] If the enable signal is not detected, S510 is executed again.

[0169] If the enable signal is detected, S520 is executed to detect the vehicle speed and the left turning angle of the steering wheel.

[0170] S530: Determine whether the vehicle speed and the left turning angle of the steering wheel meet the conditions.

[0171] The satisfying condition here means that the vehicle speed is greater than a preset vehicle speed and the steering wheel turning angle to the left is greater than a first preset angle.

[0172] If the vehicle speed and the left turning angle of the steering wheel do not meet the conditions, the process returns to S520.

[0173] If the vehicle speed and the leftward turning angle of the steering wheel meet the conditions, S540 is executed to control the braking system to output braking force to the two left wheels.

[0174] Afterwards, in the process of controlling the braking system to output braking force to the two left wheels, S550 is executed to control the driving system to increase the driving torque output to the electric vehicle.

[0175] S560: Determine whether the left turning angle of the steering wheel after returning to the center position satisfies a condition.

[0176] The condition here is that the left turning angle of the steering wheel after returning to the center position is less than a second preset angle.

[0177] If the condition is not met, the process returns to execute S540.

[0178] If the conditions are met, the control ends.

[0179] See also Figure 7 , Figure 7 A schematic diagram of a scenario in which the electric vehicle 100 provided in an embodiment of the present application turns left is shown.

[0180] exist Figure 7 middle, Figure 7 The dark-colored portion is a schematic diagram of a continuous turning process in which the electric vehicle 100 turns left from position 1 to position 2, and turns left from position 2 to position 3, by controlling the electric vehicle turning control method provided in an embodiment of the present application.

[0181] During the entire process of turning left, the combined force of the braking force and driving force of the two left wheels in the vehicle's forward direction is opposite to the vehicle's forward direction, and the combined force of the braking force and driving force of the two right wheels in the vehicle's forward direction is the same as the vehicle's forward direction. The resulting yaw moment increases and is counterclockwise, reducing the turning radius of the electric vehicle when turning left.

[0182] Figure 7 The light-colored portion in the middle is an illustrative illustration of the turning process of the electric vehicle 100 that is controlled without using the electric vehicle turning control method provided in the embodiment of the present application.

[0183] It can be seen that the electric vehicle turning control method provided in the embodiment of the present application reduces the turning radius of the electric vehicle.

[0184] In another embodiment of the present application, a vehicle controller for an electric vehicle is also provided, which is used to control the braking system and driving system of the electric vehicle to reduce the turning radius of the electric vehicle during the turning process of the electric vehicle.

[0185] In another embodiment of the present application, an electric vehicle is also provided, which includes a drive system, a braking system and a vehicle controller provided in the above embodiments, and the vehicle controller is used to control the braking system and drive system of the electric vehicle to reduce the turning radius of the electric vehicle during the turning process of the electric vehicle.

[0186] It can be understood that all relevant contents of each step involved in the above method embodiment can be referred to the embodiment of the controller and the embodiment of the electric vehicle, and the embodiments of the present application will not be repeated here.

[0187] Finally, it should be noted that the above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application 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 method for controlling turning of an electric vehicle, characterized in that: The control method is used to control the braking system and the driving system of the electric vehicle to reduce the turning radius of the electric vehicle during the turning process of the electric vehicle, and the control method includes: At the first moment, the right turning angle of the steering wheel of the electric vehicle increases from zero, and the two front wheels of the electric vehicle are controlled to turn right; At a second moment after the first moment, the steering wheel turning angle of the electric vehicle to the right increases to be greater than a first preset angle, and while controlling the drive system to output driving torque to the electric vehicle to drive the electric vehicle, the brake system of the electric vehicle is controlled to output braking force to the two right wheels of the electric vehicle.

2. The control method according to claim 1, characterized in that: The control method further comprises: At a third moment after the second moment, in the process of controlling the brake system to output a braking force to the two right wheels, the drive system is controlled to increase the drive torque output to the electric vehicle.

3. The control method according to claim 2, characterized in that: The control method further comprises: At a fourth moment after the third moment, the rightward turning angle of the steering wheel decreases to less than a second preset angle, and the braking system is controlled to stop outputting braking force to the two right wheels.

4. The control method according to claim 1, characterized in that: The control method specifically includes: At the second moment, the rightward turning angle of the steering wheel increases to be greater than the first preset angle and the speed of the electric vehicle is the first speed, and the braking system is controlled to output a first braking force to the two right wheels; At the second moment, the rightward turning angle of the steering wheel increases to be greater than the first preset angle and the speed of the electric vehicle is the second speed, and the braking system is controlled to output a second braking force to the two right wheels; The first vehicle speed is smaller than the second vehicle speed, and the first braking force is smaller than the second braking force.

5. The control method according to claim 3, characterized in that: The control method specifically includes: Between the second moment and the fourth moment, the braking force output by the braking system to the two right wheels is controlled to increase as the speed of the electric vehicle increases.

6. The control method according to claim 3, characterized in that: The control method specifically includes: Between the second moment and the fourth moment, the braking system is controlled to output a braking force to the two right wheels which increases as the rightward turning angle of the steering wheel increases.

7. The control method according to claim 3, characterized in that: The control method specifically includes: Between the second moment and the fourth moment, the braking system of the electric vehicle is controlled so that the braking force output to the right front wheel is greater than the braking force output to the right rear wheel.

8. The control method according to claim 3, characterized in that: The control method specifically includes: Between the third moment and the fourth moment, the driving torque output by the drive system to the two front wheels of the electric vehicle is controlled to increase as the braking force output by the brake system to the right front wheel increases, or the driving torque output by the drive system to the two rear wheels of the electric vehicle is controlled to increase as the braking force output by the brake system to the right rear wheel increases.

9. The control method according to claim 3, characterized in that: The control method specifically includes: Between the third moment and the fourth moment, the increase in the driving torque output by the driving system is controlled to increase as the rightward turning angle of the steering wheel increases.

10. The control method according to claim 2, characterized in that: The control method specifically includes: At the third moment, the rightward turning angle of the steering wheel increases to be greater than the first preset angle and the speed of the electric vehicle is the third speed, and the increase in the output driving torque of the driving system is controlled to be the first driving torque; At the third moment, the rightward turning angle of the steering wheel increases to be greater than the first preset angle and the speed of the electric vehicle is the fourth speed, and the increase in the output driving torque of the driving system is controlled to be the second driving torque; The third vehicle speed is lower than the fourth vehicle speed, and the first driving torque is higher than the second driving torque.

11. The control method according to claim 1, characterized in that: At the second moment, the electric vehicle travels at a speed greater than a preset speed.

12. A vehicle controller, characterized in that: The vehicle controller is configured to execute the control method according to any one of claims 1 to 11.

13. The vehicle controller according to claim 12, characterized in that: The vehicle control is used to receive a steering wheel angle signal and a vehicle speed signal; wherein: The steering wheel angle signal is used to indicate the steering wheel angle, and the steering wheel angle indicated by the steering wheel angle signal is greater than the first preset angle at the second moment; The vehicle speed signal is used to indicate the vehicle speed of the electric vehicle, and the vehicle speed of the electric vehicle indicated by the vehicle speed signal is greater than the preset vehicle speed at the first moment.

14. The vehicle controller according to claim 12, characterized in that: The vehicle controller is used to: At the second moment, a torque instruction is output to the motor controller and a braking instruction is output to the brake controller, the torque instruction is used to instruct the motor controller to control the drive motor of the electric vehicle to output driving torque, and the braking instruction is used to instruct the wheel-end braking devices of the two right wheels of the electric vehicle to output braking force to the two right wheels.

15. An electric vehicle, characterized in that: The electric vehicle comprises a vehicle controller, a drive system and a braking system as claimed in any one of claims 12 to 14; wherein: The drive system includes a motor controller and a drive motor, wherein the motor controller is used to control the drive motor to output a drive torque to the wheels of the electric vehicle; The braking system comprises a braking controller and four wheel-end braking devices, wherein the braking controller is used to control the four wheel-end braking devices to output braking force to the four wheels of the electric vehicle.

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