Control method for vehicle in-situ escape, vehicle controller and electric vehicle

Abstract

The invention discloses a control method for vehicle in-situ escape, a vehicle controller and an electric vehicle, relates to the field of new energy vehicles, and can be applied to pure electric vehicles and hybrid vehicles. The control method is used for controlling a driving system and a braking system of the electric vehicle to achieve in-situ escape of the electric vehicle in the running process that the speed of the electric vehicle is smaller than a preset speed after a user starts an in-situ escape mode. The control method comprises the steps that the driving system is controlled to output driving torque to the two coaxial wheels, and the braking system is controlled to output braking force to the wheel with the large slip rate in the two wheels. According to the scheme, the driving capacity of the whole vehicle can be effectively exerted, deterioration of road adhesion conditions is avoided, the maximum escape capacity is obtained, and the escape success rate is increased.

Description

Technical Field

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

[0002] When a vehicle is driving on a road with low adhesion and high driving resistance, it is very likely that the wheels will sink and lose power. The driver needs to seek a traction tool to get the vehicle out of trouble. Even if the traction tool cannot get the vehicle out of trouble, the driver must request support, which seriously affects the driving experience.

[0003] When a vehicle is stuck in a muddy road or under complex conditions such as a road with a low adhesion coefficient, the wheels driven by the drive motor are prone to break through the adhesion of the road and slip or even spin due to the complex adhesion conditions of each drive wheel and the high power demand of the driver. Due to the power transmission coupling differential, more torque is allocated to the slipping wheel, and the torque of the wheel on the high adhesion side is further reduced. The actual driving ability of the vehicle will be further reduced, making it more difficult for the vehicle to get out of trouble. At present, some vehicles use differential locks to force the left and right drive wheels to rotate at the same speed by locking the differential to prevent power loss due to unilateral wheel idling. However, differential locks are expensive and complex in structure, and may not achieve the maximum escape capability of the vehicle, so they are not very applicable.

[0004] Therefore, how to efficiently and simply get the electric vehicle out of trouble is a problem that needs to be solved. Summary of the invention

[0005] The present application provides a control method for a vehicle to escape from an obstacle in place, a vehicle controller and an electric vehicle, which output braking force to a slipping wheel through a braking system, effectively exert the driving ability of the entire vehicle, avoid deterioration of road adhesion conditions, obtain maximum escape capability, and improve the success rate of escape.

[0006] In the first aspect, the present application provides a control method for an electric vehicle to escape from a stuck state, the control method is used to control the driving system and braking system of the electric vehicle to escape from a stuck state when the electric vehicle is traveling at a speed lower than a preset speed after the user turns on the stuck state escape mode. The control method includes: controlling the driving system to output driving torque to two coaxial wheels and controlling the braking system to output braking force to one of the two wheels with a larger slip rate.

[0007] When a vehicle is driving on a road with low adhesion and high driving resistance, the difference in adhesion between the wheels on both sides may be too large or one wheel may be suspended, resulting in the vehicle being unable to generate sufficient driving force and getting stuck. Due to the coaxial wheel power transmission coupling differential, the torque output by the drive motor is more distributed to the slipping wheel, and the torque of the wheel on the high adhesion side is reduced. Therefore, it is necessary to adjust the torque and braking force distribution of the left and right wheels to enable the vehicle to obtain sufficient driving force and give full play to the maximum adhesion of each wheel to get out of trouble.

[0008] Electric vehicles can be set up with a separate escape-in-place mode. When the escape-in-place mode is activated, the electric vehicle will respond to the user's operation and readjust the torque output by the drive system and the braking force output by the brake system. The electric vehicle determines whether to enter the escape-in-place control strategy based on whether the escape mode is activated and the speed of the electric vehicle.

[0009] In this application, the road adhesion coefficient refers to the friction between the wheels and the road. The size of the road adhesion coefficient has an important impact on the safety and stability of vehicle driving. Tires with higher adhesion coefficients are easier to grip during driving, providing better braking and cornering performance. A lower adhesion coefficient may cause the vehicle to slip or lose control on wet or uneven roads. The road adhesion coefficient is affected by many factors, including road material, humidity, temperature, tire type and degree of wear. Under different road conditions and weather conditions, the corresponding road adhesion coefficient may be different.

[0010] In order to be able to get out of trouble on the spot, the vehicle needs to obtain sufficient driving force. Due to the complex and changeable road conditions, the adhesion coefficients of the road surfaces contacted by the four wheels of the electric vehicle are different, so the adhesion capabilities that the four wheels can exert may be different. When the slip rate of one of the two coaxial wheels is large, it means that the wheel may be idling or slipping, and the road adhesion capacity that can be exerted is low. Due to the power transmission coupling differential, the torque output by the drive motor will be more allocated to the slipping wheel, while the torque allocated to the other coaxial wheel is reduced, and the road adhesion capacity cannot be fully exerted. Therefore, the braking system needs to apply braking force to the slipping wheel, reduce the torque of the slipping wheel so that the opposite wheel can increase the torque it receives. At the same time, the drive system adjusts the output torque to control the slip rate of the slipping wheel, reduce the slip rate of the slipping wheel, and enable the slipping wheel to obtain greater driving force, so that the vehicle can get out of trouble on the spot.

[0011] According to the solution of the present application, braking force is applied to the wheel with a larger slip rate, thereby preventing the slipping wheel from being allocated too much torque, which would cause the other coaxial wheel to be unable to exert its road adhesion ability, and fully utilizing the driving force of the non-slipping wheel to achieve the vehicle's escape from trouble on the spot.

[0012] In combination with the first aspect, in certain implementations of the first aspect, when the braking system outputs braking force to a wheel with a larger slip rate, the drive motor is controlled to adjust the output torque to reduce the slip rate of one wheel.

[0013] When the adhesion of the wheel on the road changes, the speed and torque of the drive motor used to drive the wheel will also change. Therefore, the vehicle controller can perceive the changes in the road adhesion through the change in the drive motor speed detected by the resolver sensor. The actual torque actually output by the drive motor reflects the adhesion ability of the road to a certain extent. Therefore, the vehicle controller can actively adjust the torque actually output by the drive motor according to the resolver signal of the drive motor, so as to accurately control the slip rate of the tire. Through the short detection cycle of the resolver sensor near the drive motor, slip observation and torque closed-loop adjustment are performed to achieve rapid control of the slip rate.

[0014] According to the scheme of this application, the optimal slip rate is tracked based on the detected motor resolver signal and the observed road adhesion, ensuring the fastest speed to reduce slip, preventing the road adhesion from deteriorating, and driving torque to quickly close the loop, quickly and fully utilize the road adhesion capacity, and quickly get out of trouble. The braking torque intervenes smoothly to achieve drive and brake fusion, stably and quickly match the road adhesion capacity of each wheel, and exert the maximum escape force of the whole vehicle.

[0015] In combination with the first aspect, in certain implementations of the first aspect, controlling the braking system to output braking force to a wheel having a larger slip rate among the two wheels specifically includes: controlling the braking system to output braking force to one wheel and gradually increasing the braking force from a first preset value, and the first preset value changes with the change of the driving torque output by the drive system to the one wheel.

[0016] The first preset value changes with the change of the actual torque output by the drive motor used to drive one wheel in the drive system. When the adhesion of the wheel on the road changes, the actual torque of the drive motor used to drive the wheel will also change. Therefore, the vehicle controller can perceive the change of the adhesion of the road through the change of the output drive torque. The actual torque actually output by the drive motor reflects the adhesion of the road to a certain extent. Therefore, in order to meet the slip control requirements of the one wheel, the first preset value can be determined according to the drive torque output by the drive system to one wheel, and the braking force can be increased from the first preset value, and the drive-brake fusion control can be realized in combination with the adjustment of the drive torque.

[0017] According to the solution of the present application, the braking torque is smoothly intervened according to the observed road adhesion, the road adhesion capacity is quickly and fully utilized, the vehicle can quickly get out of trouble, the driving and braking fusion is achieved, the road adhesion capacity of each wheel is stably and quickly matched, and the maximum escape force of the whole vehicle is exerted.

[0018] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: controlling the driving torque output by the drive system to the two wheels to increase, and controlling the braking force output by the brake system to one wheel to increase while controlling the driving torque output by the drive system to the two wheels to increase.

[0019] The electric vehicle starts the on-the-spot escape mode and determines that the electric vehicle is in a trapped state. The braking system and the drive system begin to control the on-the-spot escape strategy. The braking system smoothly applies braking force to the slipping wheel in proportion to the actual output torque of the drive motor to ensure that the wheels on both sides of the coupling can obtain maximum adhesion. At the same time, the drive system observes the road adhesion based on the resolver signal, tracks the optimal slip rate, increases the output torque, reduces the slip as quickly as possible, and prevents the road adhesion from deteriorating.

[0020] When the braking force output by the braking system increases, the drive motor performs closed-loop control with a target slip rate. At this time, the braking force output by the braking system serves as an influencing factor of the closed-loop control, and the output torque is adjusted. The braking force increases and the wheel speed decreases. In order to achieve the target slip rate, the output torque increases.

[0021] According to the solution of the present application, the driving torque quickly controls the target slip rate in a closed loop, and the braking torque intervenes smoothly to achieve drive and braking fusion, stably and quickly match the road adhesion capabilities of each wheel, and maximize the vehicle's escape force.

[0022] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: controlling the driving torque output by the drive system to the two coaxial wheels to change as the slip rate of the other wheel of the two wheels changes.

[0023] When one of the two coaxial wheels slips and the other wheel does not slip, the slip rate of both wheels can be controlled to the target slip rate through the fusion control of the braking system and the drive system. The motor controller in the drive system performs closed-loop control on the slip rate of the wheel based on the resolver signal and the wheel speed signal. Since the torque output by the drive motor drives the two coaxial wheels at the same time, when the drive motor increases the output torque in order to increase the driving force of the non-slipping wheel, the slip rate of the slipping wheel will increase. The braking system smoothly applies braking force to the slipping wheel, and the motor controller detects the resolver signal and actual output torque of the drive motor, senses the road adhesion conditions, and suppresses the near-end low-latency closed-loop slip, so that the driving torque and braking force of the wheel on the slipping side can be superimposed to output the total driving control torque, and the driving torque of the wheel on the non-slipping side is increased and the slip rate is reduced.

[0024] According to the solution of the present application, the driving torque quickly controls the target slip rate in a closed loop, and the braking torque intervenes smoothly to achieve drive and braking fusion, stably and quickly match the road adhesion capabilities of each wheel, and maximize the vehicle's escape force.

[0025] In combination with the first aspect, in certain implementations of the first aspect, in the process of controlling the drive system to output drive torque to two wheels and controlling the brake system to output braking force to one wheel, the slip rate of one wheel is reduced.

[0026] In combination with the first aspect, in certain implementations of the first aspect, the control method further includes: controlling the driving torque output by the drive system to the two wheels and the braking force output by the brake system to one wheel to increase simultaneously. After the braking force output by the brake system to one wheel increases to a second preset value, controlling the braking force output by the brake system to one wheel to remain unchanged and controlling the drive system to adjust the driving torque output to the two wheels.

[0027] The braking system quickly reduces the slip rate of the wheel on the slipping side by outputting braking force, and the driving torque of the other coaxial wheel increases. The driving system can determine the slip rate of the other coaxial wheel based on the resolution signal and the wheel speed. When the slip rate of the other coaxial wheel reaches the target slip rate, the braking force output by the braking system no longer increases. The driving system controls the slip rate of the slipping wheel to reach the target slip rate by adjusting the output torque based on the resolution signal and the wheel speed signal, thereby increasing the driving force of the slipping wheel.

[0028] According to the solution of the present application, the drive system outputs torque for rapid closed-loop target slip rate control, and the brake system outputs braking force for smooth intervention, thereby achieving drive and braking fusion, stably and rapidly matching the road adhesion capabilities of each wheel, and exerting the maximum escape force of the entire vehicle.

[0029] In combination with the first aspect, in certain implementations of the first aspect, the control method includes: in the process of the braking system outputting braking force to the one wheel with a larger slip rate among the two wheels, when the slip rate of one wheel and the slip rate of the other wheel of the two coaxial wheels are both greater than the slip threshold, controlling the braking system to reduce the braking force output to the one wheel to zero.

[0030] The speed of a slipping wheel will be higher than that of other non-slipping wheels, so the electric vehicle determines the number and position of slipping wheels among the coaxial wheels based on the wheel speed of each wheel. When one of the coaxial wheels slips, the braking system smoothly applies braking force according to the set target, and eventually reaches a braking force balance state, with deep fusion of drive and braking. When both coaxial wheels slip, it is difficult for the braking system to obtain sufficient driving force on either side, so the braking system smoothly stops outputting braking force.

[0031] When the slip rate of one wheel and the slip rate of another wheel coaxial with the one wheel are both greater than the slip threshold, the two coaxial wheels both slip and it is difficult to obtain sufficient driving force. At this time, the braking force is no longer applied.

[0032] According to the solution of the present application, braking force is applied according to the actual state of the vehicle and the slippage of the wheels, and the braking force is applied smoothly according to the slip rate of the wheels on both sides to achieve drive and braking balance on both sides and deep integration of drive and braking, ensuring quick and full utilization of the road adhesion capacity and achieving rapid escape from difficulties.

[0033] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: in the process of controlling the drive system to output drive torque to two wheels and controlling the braking system to output braking force to one wheel, the drive torque output by the drive system to the two wheels is different from the torque indicated by the opening of the accelerator pedal and the braking force output by the braking system to one wheel is different from the braking force indicated by the opening of the brake pedal.

[0034] The accelerator pedal in this application may also be referred to as an accelerator pedal or an acceleration pedal. The opening of the accelerator pedal can indicate the driving force required by the driver. The larger the opening of the accelerator pedal, the greater the driver's demand for driving, and the corresponding torque required to be output by the drive motor is also greater. The motor controller can control the drive motor to output the torque indicated by the accelerator pedal opening according to the accelerator pedal opening. The larger the accelerator pedal opening, the greater the torque output by the drive motor. The smaller the accelerator pedal opening, the smaller the torque output by the drive motor. The motor controller controls the torque output by the drive motor to change with the change in the opening of the accelerator pedal.

[0035] The brake pedal in this application may also be referred to as the brake or brake pedal. The opening of the brake pedal can indicate the amount of braking force required by the driver. The larger the opening of the brake pedal, the greater the driver's demand for braking, and the greater the torque required to be output by the brake system. When the vehicle is in normal driving, the brake system can output the torque indicated by the opening of the brake pedal according to the opening of the brake pedal. The larger the opening of the brake pedal, the greater the braking force output by the brake system, and the smaller the opening of the brake pedal, the smaller the braking force output by the brake system. The braking force output by the brake system changes with the change of the opening of the brake pedal.

[0036] When the electric vehicle's on-the-spot escape mode is activated, the braking force output by the brake system is different from the braking force indicated by the brake pedal opening, and the torque output by the drive motor is different from the torque indicated by the accelerator pedal opening. The braking force output by the brake system does not change with the change of the brake pedal opening, and the torque output by the drive motor does not change with the change of the brake pedal opening. At this time, the motor controller performs a closed loop of torque, which directly determines the torque output by the drive motor, which is different from the torque indicated by the torque signal sent by the vehicle controller.

[0037] According to the solution of the present application, the actual adhesion conditions of different road surfaces are quickly identified through the rotary transformer signal, and the output drive torque and braking force are quickly closed-loop controlled according to the actual state of the vehicle, thereby improving the control accuracy and speed, and increasing the possibility and efficiency of escaping from trouble on the spot.

[0038] In combination with the first aspect, in certain implementations of the first aspect, the control method specifically includes: in the process of controlling the drive system to output drive torque to two wheels and controlling the braking system to output braking force to one wheel, when the brake pedal opening is greater than a preset opening, controlling the drive system to stop outputting drive torque and controlling the braking system to stop outputting braking force.

[0039] When the electric vehicle is in the on-the-spot escape mode control, the user can quickly cancel the on-the-spot escape mode control by stepping on the brake pedal. When the user determines that the on-the-spot escape mode cannot be continued, or it is not necessary to perform the on-the-spot escape mode, the user can quickly exit by changing the opening of the brake pedal, thus avoiding the deterioration of road conditions or the vehicle losing control.

[0040] According to the solution of the present application, the user can exit the on-the-spot escape mode by pressing the brake pedal, which allows for a quick exit response, thereby avoiding further deterioration of road conditions and improving the controllability and safety of the vehicle.

[0041] In combination with the first aspect, in certain implementations of the first aspect, the slip rate of one wheel of the electric vehicle is greater than a slip threshold and the slip rate of the other wheel of the two coaxial wheels is less than or equal to the slip threshold, and the drive system is controlled to output drive torque to the two coaxial wheels and the braking system is controlled to output braking force to the wheel with the larger slip rate of the two wheels.

[0042] The electric vehicle may include multiple sensors, and the sensors are used to detect the running status information of the vehicle. The multiple sensors may include various other sensors such as a sensor for detecting the speed of the electric vehicle, a sensor for detecting the wheel speed of each wheel, a sensor for detecting the lateral acceleration and longitudinal acceleration of the vehicle. The running status information of the vehicle may be obtained directly from the sensor, or indirectly through calculation of one or more sensor information.

[0043] When the electric vehicle's escape-in-place mode is activated, the electric vehicle can determine whether the vehicle is in a trapped state based on the operating status information obtained from the sensor. When the vehicle is in a trapped state, the wheels rotate rapidly, but the vehicle speed is almost zero, because the vehicle is trapped at this time, and the vehicle cannot move despite the rapid rotation of the wheels. When the vehicle is in a trapped state, the following states may exist: the vehicle speed is less than the vehicle speed threshold, the driving force of at least one wheel is less than the driving force threshold, the vehicle body yaw rate is less than the yaw rate threshold, the wheel speed of at least one wheel is greater than the wheel speed threshold, and the slip rate of at least one wheel is greater than the slip threshold. Therefore, when the escape-in-place mode is activated and one or more of the above conditions are used to determine whether the vehicle is in a trapped state, if the escape-in-place control is required, the method is executed, and if not, the original state is maintained.

[0044] According to the solution of the present application, the vehicle's trapped state can be judged timely and accurately, ensuring that the vehicle's in-situ escape strategy is applied when the vehicle is trapped, avoiding false triggering situations, and improving the accuracy and reliability of vehicle control.

[0045] In combination with the first aspect, in certain implementations of the first aspect, the control method further includes: controlling the drive system to adjust the output torque to reduce the slip rate of one wheel and the other wheel of the two coaxial wheels to a target slip rate.

[0046] The vehicle controller is used to adjust the torque output by the drive motor according to the vehicle speed and the speed of the drive motor indicated by the resolver sensor of the electric vehicle. The adhesion of the tire fluctuates in real time. When the adhesion of the tire changes, the slip rate of the tire will also change. Correspondingly, the speed and torque of the drive motor used to drive the tire will change. Therefore, the change in the road adhesion can be sensed and observed through the change in the rotor speed of the drive motor detected by the resolver sensor. The vehicle controller can adjust the actual output torque of the drive motor according to the resolver signal of the drive motor, thereby accurately controlling the slip rate of the tire.

[0047] According to the solution of the present application, the change in the road adhesion coefficient is accurately determined using the resolver sensor signal of the drive motor, the timing for torque adjustment is accurately calculated in the motor controller, the torque output is adjusted instantaneously, the response is rapid, and the possibility of the vehicle getting out of trouble is increased.

[0048] In combination with the first aspect, in certain implementations of the first aspect, in the process of controlling the drive system to output drive torque to two wheels and controlling the braking system to output braking force to one wheel, the wheel speed difference between one wheel and the other wheel of the two coaxial wheels gradually decreases.

[0049] In some traditional cars, the differential lock can be set to make the rotation speed of the coaxial wheels the same, so that when getting out of trouble, the slipping wheel will not be allocated too much torque. However, through the cooperation of the drive system and the braking system, the slip rate of both wheels can be reduced at the same time, the rotation speed of the slipping wheel can be reduced, and the slipping wheel will not be allocated more torque. The rotation speed of the two coaxial wheels can still be different. Unlike the differential lock, it will not blindly make the rotation speed of the two wheels consistent, thus achieving a better effect.

[0050] According to the solution of the present application, there is no need for a differential lock to lock the differential, and on-the-spot escape control can be achieved through the original driving system and braking system, ensuring rapid and full utilization of the road adhesion capacity, achieving rapid escape, saving costs, high applicability, and improving the economy of the vehicle.

[0051] In combination with the first aspect, in certain implementations of the first aspect, the magnitude of the output torque of the drive system is less than or equal to the torque limit.

[0052] In the process of getting out of trouble, because of the large torque demand, in the process of controlling the drive motor to increase the torque, it is also necessary to safely limit the final output torque. The torque limit needs to consider the external characteristic limit of the drive motor, the maximum discharge capacity limit of the power battery, and the controllable maximum torque limit. If the output torque is too large, it may cause damage to the vehicle hardware and loss of control of the vehicle.

[0053] According to the solution of the present application, the maximum output torque of the drive motor is safely limited, thereby ensuring the safety of the vehicle during the escape process and exerting the maximum escape capability of the vehicle.

[0054] In combination with the first aspect, in certain implementations of the first aspect, the user starting the escape-in-place mode includes the user controlling the electric vehicle to start the escape-in-place mode by touching the central control screen of the electric vehicle or activating an escape button.

[0055] The electric vehicle can enter the escape-in-place mode through the central control screen or the escape button. When the escape-in-place mode is turned off, the electric vehicle does not perform escape-in-place control, the drive motor outputs the torque indicated by the opening of the electric vehicle's accelerator pedal, and the brake system outputs the torque indicated by the opening of the brake pedal. When the escape-in-place mode is turned on, the electric vehicle detects whether the electric vehicle is in a trapped state. When the electric vehicle is in a trapped state and needs to implement an escape-in-place strategy, the electric vehicle controls the braking system to output a braking force that is different from the braking force indicated by the opening of the brake pedal, and controls the drive motor to output a torque that is different from the torque indicated by the opening of the accelerator pedal.

[0056] An escape button may also be provided on the electric vehicle for the driver to operate. Exemplarily, the escape button may be a physical button, and the driver may press the physical button to activate the electric vehicle's escape mode. Also exemplarily, the escape button may be a virtual button on the central control screen, and the driver may select the escape mode to activate the electric vehicle's escape strategy. Also exemplarily, the drift button may also be provided indirectly, for example, by being incorporated into a driving mode button or other function buttons. This application does not limit the setting method and form of the escape button.

[0057] According to the solution of the present application, the on-the-spot escape mode is set so that the driver can freely choose whether to turn it on or off, thereby improving the controllability and safety of the vehicle.

[0058] In combination with the first aspect, in certain implementations of the first aspect, the vehicle speed threshold is less than or equal to 15 km / h. The target slip ratio is greater than or equal to 0.1 and less than or equal to 0.3.

[0059] The thresholds in this application, such as wheel thresholds, slip thresholds, target slip rates, etc., may be pre-calibrated based on actual vehicle experiments and / or model calculations. They may be pre-set based on comprehensive consideration of vehicle requirements and vehicle performance, or may be set based on specific application scenarios, or may be adjusted upward or downward based on the pre-set values ​​to optimize the value, and the adjustment direction and the optimization value may be determined based on specific application scenarios.

[0060] According to the solution of the present application, by setting a vehicle speed threshold, it is ensured that the vehicle's on-the-spot escape strategy is applied when the vehicle is stuck, thereby avoiding false triggering situations. By setting a target slip rate, the accuracy and reliability of vehicle control are improved.

[0061] In a second aspect, the present application provides a vehicle controller for an electric vehicle to escape from a jam on the spot. The vehicle controller is used to execute the electric vehicle control method described in the first aspect or any possible implementation of the first aspect.

[0062] The vehicle controller provided in the present application may be a whole vehicle controller of an electric vehicle, a motor controller, or a separately set controller with control capabilities.

[0063] In a third aspect, the present application provides an electric vehicle, which includes the vehicle controller, braking system, accelerator pedal and brake pedal provided in the second aspect, the accelerator pedal is used to indicate the torque output to the wheels of the electric vehicle, and the brake pedal is used to indicate the braking torque output to the wheels of the electric vehicle.

[0064] In combination with the third aspect, in certain implementations of the third aspect, the electric vehicle includes a differential, and the differential is used to make the rotation speeds of the coaxial wheels different. When the speed of the electric vehicle is less than the speed threshold and the slip rate of one wheel of the electric vehicle is greater than the slip threshold, the wheel speeds of the two coaxial wheels are different. After the user turns on the in-situ escape mode, the braking system outputs a braking force to one wheel and gradually increases it from a first preset value and controls the drive motor to adjust the output torque to reduce the slip rate of one wheel, and the wheel speed difference of the two coaxial wheels gradually decreases.

[0065] The beneficial effects of other aspects can refer to the beneficial effects described in the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 is a schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0067] Figure 2 is a schematic diagram of the architecture of an electric vehicle provided in an embodiment of the present application;

[0068] Figure 3 is a schematic diagram of an electric vehicle escape button provided in an embodiment of the present application;

[0069] Figure 4 It is a schematic diagram of a control strategy for electric vehicle escape from trouble in situ provided in an embodiment of the present application;

[0070] Figure 5 It is a schematic diagram of the on-the-spot escape control process provided in an embodiment of the present application. DETAILED DESCRIPTION

[0071] The following will describe the technical solution in the present application in conjunction with the accompanying drawings. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0072] Due to complex working conditions such as muddy roads or low road adhesion coefficients during driving, the wheels of the vehicle are likely to sink and lose power. Since the adhesion conditions of each driving wheel are relatively complex and the driver's power demand is large, the wheels driven by the drive motor are prone to break through the road adhesion and slip or even spin. Due to the power transmission coupling differential, more torque is allocated to the slipping wheel, and the torque of the wheel on the high adhesion side is further reduced. The actual driving ability of the whole vehicle will be further reduced, increasing the difficulty of the car to get out of trouble. At present, some vehicles will use differential locks to force the left and right driving wheels to have equal speeds by locking the differential to prevent power loss due to unilateral wheel idling. However, differential locks are expensive and complex in structure, and may not be able to achieve the maximum ability of the vehicle to get out of trouble, and their adaptability is not high.

[0073] In one possible implementation, the motor torque is distributed according to different road adhesion coefficients, load conditions, and driver-requested torque to improve the passing performance.

[0074] It should be understood that in the above implementation, when the vehicle is stuck in place, some or all wheels may slip, and the wheel slip rate and road adhesion estimation time are prolonged, resulting in a prolonged closed loop of driving force control, which may further deteriorate the adhesion conditions and make it impossible to get out of trouble. The driving torque of each wheel does not fully utilize the maximum adhesion capacity of the road, does not exert the maximum driving force, and the success rate of getting out of trouble is low.

[0075] Based on the above problems, the present application provides a control method for a vehicle to escape from an obstacle in place, a vehicle controller and an electric vehicle, which apply braking force to the slipping wheels through the braking system, effectively exert the driving ability of the entire vehicle, avoid deterioration of road adhesion conditions, obtain maximum escape capability, and improve the success rate of escape.

[0076] Figure 1 and Figure 2 It is a schematic diagram of the architecture of the electric vehicle 10 provided in an embodiment of the present application.

[0077] like Figure 1 As shown, the electric vehicle 10 includes a vehicle controller 20, a drive system 30, a braking system 60 and multiple wheels. The drive system 30 includes a motor controller 40 and a drive motor 50. The motor controller 40 is used to output current to the drive motor 50 to control the drive motor 50 to output torque to drive the electric vehicle 10. The braking system 60 is used to brake the electric vehicle 10 by outputting braking force.

[0078] The vehicle controller in the present application may be the motor controller 40 of the electric vehicle 10, or the vehicle controller 20, or a separately provided controller with control capabilities.

[0079] The electric vehicle 10 may be a wheel-side four-drive motor drive architecture, where the drive motor 50 is arranged on the side of the driven wheel and is controlled by a separate motor controller 40. The electric vehicle 10 may also be a centralized drive motor drive architecture, where two drive motors for driving two front wheels or two rear wheels are arranged together. The motor controller 40 may be one or more. The motor controller 40 and the drive motor 50 may correspond one to one, or one motor controller 40 may correspond to multiple drive motors 50. The motor controller 40 is used to control one or more drive motors 50 to output torque to drive the electric vehicle 10.

[0080] In one embodiment, the electric vehicle 10 may be a wheel-side four-drive motor drive architecture, where the drive motor is arranged beside the driven wheel and is controlled by a separate motor controller. The electric vehicle 10 may also be a centralized four-motor drive architecture, where two drive motors for driving two front wheels or two rear wheels are arranged together.

[0081] In one embodiment, the electric vehicle 10 may use one drive motor to drive two front wheels of the electric vehicle 10 , and / or use one drive motor to drive two rear wheels of the electric vehicle 10 .

[0082] The vehicle controller provided in the implementation of the present application may be any one of a plurality of motor controllers. The following embodiments only take the vehicle controller as the motor controller 40 as an example. When the vehicle controller is other controllers, similar understanding may be obtained by referring to the description.

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

[0084] In one embodiment, the motor controller 40 includes a signal interface, and the motor controller 40 is connected to the vehicle controller 20 and other motor controllers 40 through the signal interface. The vehicle controller 20 is connected to the accelerator pedal signal, and the vehicle controller 20 calculates the vehicle torque demand according to the opening of the accelerator pedal during the driving of the electric vehicle 10, and sends a torque signal to the motor controller 40 according to the vehicle torque demand. Each motor controller 40 controls the corresponding drive motor 50 to output torque to drive the corresponding wheel according to the indication of the torque signal.

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

[0086] In one embodiment, the motor controller 40 is connected to a resolver sensor via a signal interface. The resolver sensor is used to detect the rotation speed of the drive motor 50 controlled by the motor controller 40 . The motor controller 40 is used to receive a signal from the resolver sensor.

[0087] The resolver sensor can accurately detect the position, direction and speed of the motor rotor, and is responsible for monitoring and extracting the rotation speed of the drive motor. It has a high sampling rate and is directly connected to the motor controller 40, with short signal transmission time and higher stability.

[0088] In one embodiment, the motor controller 40 also obtains a vehicle speed signal and wheel speed signals of multiple wheels from the vehicle controller 20 or other sensors of the electric vehicle 10 through a signal interface. The vehicle speed signal is used to indicate the speed of the electric vehicle 10, and the wheel speed signal is used to indicate the rotational speed of each wheel of the electric vehicle 10.

[0089] like Figure 2 As shown, the braking system 60 includes a brake controller (not shown in the figure) and a plurality of wheel-end brake devices 61, and the brake controller is connected to the brake pedal signal. The brake controller can be used to determine the braking force according to the opening of the brake pedal. During the driving process, when the electric vehicle 10 needs to brake, the driver steps on the brake pedal, the brake controller receives the brake pedal signal from the brake pedal and outputs a braking force distribution signal to the wheel-end brake device 61, and the wheel-end brake device 61 is used to receive the braking force distribution signal and output a clamping force to the brake disc according to the instruction of the braking force distribution signal, thereby generating a friction braking force, so that the electric vehicle 10 is braked.

[0090] In one embodiment, the vehicle controller 20 is connected to the brake pedal. The vehicle controller 20 calculates the vehicle braking demand based on the brake pedal opening of the electric vehicle 10 during driving and sends a braking signal to the brake controller based on the vehicle braking demand. The brake controller controls the corresponding hydraulic brake device to brake the corresponding wheel according to the indication of the braking signal.

[0091] The electric vehicle 10 includes a differential, which is used to make the rotation speeds of the two coaxial wheels different. When the speed of the electric vehicle is less than a speed threshold and the slip rate of one wheel of the electric vehicle is greater than the slip threshold, the wheel speeds of the two coaxial wheels are different.

[0092] like Figure 3 As shown, in one embodiment, the electric vehicle 10 includes an escape button.

[0093] An escape button may be provided on the electric vehicle 10 for the driver to operate. Exemplarily, the escape button may be a physical button, and the driver may press the physical button to activate the on-site escape mode of the electric vehicle. Also exemplarily, the escape button may be a virtual button on the central control screen, and the driver may select the on-site escape mode to activate the on-site escape strategy of the electric vehicle. Also exemplarily, the drift button may also be provided indirectly, for example, by being incorporated into a driving mode button or other function buttons. This application does not limit the setting method and form of the escape button.

[0094] The control method for escaping a vehicle in situ provided by the present application is described below.

[0095] like Figure 4As shown, when the vehicle is running normally, the vehicle controller 20 sends a torque signal to the motor controller 40 according to the opening of the accelerator pedal, and the motor controller 40 controls the drive motor 50 to output the torque indicated by the opening of the accelerator pedal. The sensor of the electric vehicle 10 detects the speed of the electric vehicle 10 and the wheel speeds of the four wheels and sends them to the vehicle controller 20 and / or the motor controller 40.

[0096] When the vehicle is driving on a road with low adhesion and high driving resistance, the difference in adhesion between the two wheels may be too large or one wheel may be suspended in the air, causing the vehicle to fail to generate sufficient driving force and get stuck. At this time, the user can control the electric vehicle to start the on-site escape mode by touching the central control screen of the electric vehicle or activating the escape button.

[0097] The control method for getting out of a jam on the spot is used to control the driving system 30 and the braking system 60 of the electric vehicle 10 to get out of a jam on the spot when the electric vehicle 10 is traveling at a speed lower than a preset speed after the user turns on the jam-free mode. The control method includes: controlling the driving system 30 to output driving torque to two coaxial wheels and controlling the braking system 60 to output braking force to the wheel with a larger slip rate among the two wheels.

[0098] According to the solution of the present application, braking force is applied to the wheel with a larger slip rate, thereby preventing the slipping wheel from being allocated too much torque, which would cause the other coaxial wheel to be unable to exert its road adhesion ability, and fully utilizing the driving force of the non-slipping wheel to achieve the vehicle's escape from trouble on the spot.

[0099] In one embodiment, the control method includes: when the slip rate of one wheel of the electric vehicle 10 is greater than a slip threshold and the slip rate of the other wheel of the two coaxial wheels is less than or equal to the slip threshold, controlling the drive system 30 to output driving torque to the two coaxial wheels and controlling the braking system 60 to output braking force to the wheel with the larger slip rate of the two wheels.

[0100] The electric vehicle 10 may include a plurality of sensors for detecting the running state information of the vehicle. The plurality of sensors may include a sensor for detecting the speed of the electric vehicle 10, a sensor for detecting the wheel speed of each wheel, a sensor for detecting the lateral acceleration and longitudinal acceleration of the vehicle, and other various other sensors. The running state information of the vehicle may be obtained directly from the sensor, or may be obtained indirectly by calculating one or more sensor information.

[0101] When the in-situ escape mode of the electric vehicle 10 is activated, the electric vehicle 10 can determine whether the vehicle is in a trapped state based on the operating status information obtained from the sensor. In the trapped state of the vehicle, the wheels rotate rapidly, but the vehicle speed is almost zero, because the vehicle is trapped at this time, and the vehicle cannot move despite the rapid rotation of the wheels. When the vehicle is in a trapped state, the following states may exist: the vehicle speed is less than the vehicle speed threshold, the driving force of at least one wheel is less than the driving force threshold, the vehicle body yaw rate is less than the yaw rate threshold, the wheel speed of at least one wheel is greater than the wheel speed threshold, and the slip rate of at least one wheel is greater than the slip threshold. Therefore, when the in-situ escape mode is activated and one or more of the above conditions are used to determine whether the vehicle is in a trapped state, if in-situ escape control is required, the method is executed, and if not, the original state is maintained.

[0102] According to the solution of the present application, the vehicle's trapped state can be judged timely and accurately, ensuring that the vehicle's in-situ escape strategy is applied when the vehicle is trapped, avoiding false triggering situations, and improving the accuracy and reliability of vehicle control.

[0103] When one of the two coaxial wheels slips and the other wheel does not slip, the slip rates of both wheels can be controlled to the target slip rate through the fusion control of the braking system 60 and the drive system 30. The motor controller 40 in the drive system 30 performs closed-loop control on the slip rate of the wheel based on the rotary signal and the wheel speed signal. Since the torque output by the drive motor 50 drives the two coaxial wheels at the same time, when the drive motor 50 increases the output torque in order to increase the driving force of the non-slipping wheel, the slip rate of the slipping wheel will increase. The braking force is smoothly applied to the slipping wheel through the braking system 60, and at the same time, the motor controller 40 detects the rotary signal and the actual output torque of the drive motor 50, senses the road adhesion conditions, and suppresses the near-end low-latency closed-loop slip, so that the driving torque and braking force of the slipping side wheel can be superimposed to output the total driving control torque, and the driving torque of the non-slipping side wheel is increased and the slip rate is reduced.

[0104] In one embodiment, the control method includes: controlling the braking system 60 to output braking force to a wheel having a larger slip rate among the two wheels, specifically including controlling the braking system 60 to output braking force to one wheel and gradually increasing the braking force from a first preset value, and the first preset value changes with the change of the driving torque output by the drive system 30 to one wheel.

[0105] In one embodiment, the control method includes: in the process of controlling the drive system 30 to output driving torque to two wheels and controlling the braking system 60 to output braking force to one wheel, the driving torque output by the drive system 30 to the two wheels is different from the torque indicated by the opening of the accelerator pedal and the braking force output by the braking system 60 to one wheel is different from the braking force indicated by the opening of the brake pedal.

[0106] In this application, slip refers to the proportional relationship between wheel sliding and rotation. The actual slip can be calculated by measuring the linear velocity and angular velocity of the wheel. The actual slip reflects the relative motion between the wheel and the ground, which is very important for estimating the adhesion coefficient of the road surface.

[0107] In order to be able to get out of trouble on the spot, the vehicle needs to obtain sufficient driving force. Due to the complex and changeable road conditions, the road adhesion coefficients of the four wheels of the electric vehicle 10 are different, so the adhesion capabilities that the four wheels can exert may be different. When the slip rate of one of the two coaxial wheels is large, it means that the one wheel may be idling or slipping, and the road adhesion capability that can be exerted is low. Due to the power transmission coupling differential, the torque output by the drive system 30 will be more allocated to the slipping wheel, while the torque allocated to the other coaxial wheel is reduced, and the road adhesion capability cannot be fully exerted. Therefore, the braking system 60 needs to apply braking force to the slipping wheel, reduce the torque of the slipping wheel so that the opposite wheel can increase the torque received. At the same time, the drive system 30 adjusts the output torque to control the slip rate of the slipping wheel, reduce the slip rate of the slipping wheel, and enable the slipping wheel to obtain greater driving force, so as to achieve the vehicle's escape from trouble on the spot.

[0108] In one embodiment, the first preset value may be the road adhesion of the wheel on the slipping side multiplied by a proportional coefficient, and the braking force is smoothly adjusted through inertial filtering to meet the adhesion capacity limit of the wheel on the opposite side, thereby achieving smooth escape.

[0109] In one embodiment, in the process of controlling the driving system 30 to output driving torque to two wheels and controlling the braking system 60 to output braking force to one wheel, the slip rate of one wheel is reduced.

[0110] When the adhesion of the wheel to the road changes, the speed and torque of the drive motor 50 used to drive the wheel will also change. Therefore, the vehicle controller can perceive the change in the adhesion of the road surface through the change in the speed of the drive motor 50 detected by the resolver sensor. The actual torque actually output by the drive motor 50 reflects the adhesion ability of the road surface to a certain extent. Therefore, the vehicle controller can actively adjust the torque actually output by the drive motor 50 according to the resolver signal of the drive motor 50, so as to accurately control the slip rate of the tire. Through the short detection cycle of the resolver sensor near the drive motor 50, slip observation is performed, and torque closed-loop adjustment is performed to achieve rapid control of the slip rate.

[0111] According to the scheme of this application, the optimal slip rate is tracked based on the detected motor resolver signal and the observed road adhesion, ensuring the fastest speed to reduce slip, preventing the road adhesion from deteriorating, and driving torque to quickly close the loop, quickly and fully utilize the road adhesion capacity, and quickly get out of trouble. The braking torque intervenes smoothly to achieve drive and brake fusion, stably and quickly match the road adhesion capacity of each wheel, and exert the maximum escape force of the whole vehicle.

[0112] In one embodiment, the control method specifically includes: controlling the drive system 30 to increase the driving torque output to the two wheels, and controlling the braking system to increase the braking force output to one wheel while controlling the drive system to increase the driving torque output to the two wheels.

[0113] In one embodiment, the control method specifically includes: The control method specifically includes controlling the driving torque output by the drive system 30 to the two coaxial wheels to change with the change of the slip rate of the other wheel of the two wheels.

[0114] When the user turns on the escape mode of the electric vehicle 10, the escape strategy is entered according to the escape mode confirmation and low speed judgment. The electric vehicle 10 detects the rotary signal and actual output torque of the drive motor 50, senses the road adhesion conditions, suppresses the near-end low-latency closed-loop slip, and quickly obtains the road adhesion of the wheels on both sides to ensure the rapid and full use of the road adhesion capacity. The driving torque control method targets the slip rate obtained by the near-end closed-loop to track the target slip rate, and outputs the total driving control torque through the superposition of PI control and braking torque to achieve system stability control.

[0115] When one of the two coaxial wheels slips and the other wheel does not slip, the slip rates of both wheels can be controlled to the target slip rate through the fusion control of the braking system 60 and the drive system 30. The motor controller 40 in the drive system 30 performs closed-loop control on the slip rate of the wheel based on the rotary signal and the wheel speed signal. Since the torque output by the drive motor 50 drives the two coaxial wheels at the same time, when the drive motor 50 increases the output torque in order to increase the driving force of the non-slipping wheel, the slip rate of the slipping wheel will increase. The braking force is smoothly applied to the slipping wheel through the braking system 60, and the motor controller 40 detects the rotary signal of the drive motor and the actual output torque, senses the road adhesion conditions, and suppresses the near-end low-latency closed-loop slip, so that the driving torque and braking force of the slipping side wheel can be superimposed to output the total driving control torque, and the driving torque of the non-slipping side wheel is increased and the slip rate is reduced.

[0116] In one embodiment, the control method specifically includes: in the process of controlling the driving system 30 to output driving torque to two wheels and controlling the braking system 60 to output braking force to one wheel, the slip rate of one wheel is reduced.

[0117] In one embodiment, the control method specifically includes: the control method further includes controlling the drive system to adjust the output torque to reduce the slip rate of one wheel and the other wheel of the two coaxial wheels to a target slip rate.

[0118] The vehicle controller is used to adjust the torque output by the drive motor 50 according to the vehicle speed and the rotation speed of the drive motor indicated by the resolver sensor of the electric vehicle. The adhesion of the tire fluctuates in real time. When the adhesion of the tire changes, the slip rate of the tire will also change. Correspondingly, the rotation speed and torque of the drive motor used to drive the tire will change. Therefore, the change in the road adhesion can be sensed by the change in the rotor speed of the drive motor 50 detected by the resolver sensor, so that the vehicle controller can adjust the torque actually output by the drive motor 50 according to the resolver signal of the drive motor 50, thereby accurately controlling the slip rate of the tire.

[0119] When the braking force output by the braking system 60 increases, the drive motor 50 performs closed-loop control with a target slip rate. At this time, the braking force output by the braking system 60 serves as an influencing factor of the closed-loop control, and the output torque is adjusted. The braking force increases and the wheel speed decreases. In order to achieve the target slip rate, the output torque increases.

[0120] In one embodiment, the control method further includes: controlling the driving torque output by the drive system 30 to the two wheels and the braking force output by the brake system 60 to one wheel to increase simultaneously. After the braking force output by the brake system 60 to one wheel increases to a second preset value, controlling the braking force output by the brake system 60 to one wheel to remain unchanged and controlling the drive system 30 to adjust the driving torque output to the two wheels.

[0121] The braking system 60 quickly reduces the slip rate of the wheel on the slipping side by outputting braking force, and the driving torque of the other coaxial wheel increases. The drive system 30 can determine the slip rate of the other coaxial wheel based on the rotational signal and the wheel speed. When the slip rate of the other coaxial wheel reaches the target slip rate, the braking force output by the braking system 60 no longer increases. The drive system 30 controls the slip rate of the slipping wheel to reach the target slip rate by adjusting the output torque based on the rotational signal and the wheel speed signal, thereby increasing the driving force of the slipping wheel.

[0122] In one embodiment, the control method includes: during the process of the braking system 60 outputting braking force to the one wheel with a larger slip rate among the two wheels, when the slip rate of one wheel and the slip rate of the other wheel among the two coaxial wheels are both greater than the slip threshold, controlling the braking system 60 to reduce the braking force output to the one wheel to zero.

[0123] The wheel speed of the slipping wheel will be higher than that of other non-slipping wheels, so the electric vehicle 10 determines the number and position of the slipping wheels among the coaxial wheels based on the wheel speeds of each wheel. When one of the coaxial wheels slips, the braking system 60 smoothly applies the braking force according to the set target, and eventually reaches a braking force balance state, with deep fusion of drive and braking. When both coaxial wheels slip, it is difficult for the braking system 60 to obtain sufficient driving force on either side, so the braking system 60 smoothly stops outputting the braking force.

[0124] When the slip rate of one wheel and the slip rate of the other wheel of the two coaxial wheels are both greater than the slip threshold, the two coaxial wheels both slip and it is difficult to obtain sufficient driving force. At this time, the braking force is no longer applied.

[0125] The braking system 60 of the electric vehicle 10 first determines the number of coaxial wheels that are slipping and the slipping wheels, and confirms the road adhesion of the slipping side wheel according to the actual output torque of the drive motor 50 of the drive system 30. When the number of coaxial slipping wheels is two, the braking force is smoothly withdrawn using inertial filtering. When there is only one slipping wheel, the braking force is smoothly applied according to the set target, and finally a braking force balance state can be achieved, and the driving and braking are deeply integrated.

[0126] In one embodiment, in the process of controlling the driving system 30 to output driving torque to two wheels and controlling the braking system 60 to output braking force to one wheel, the difference between the wheel speed of one wheel and the wheel speed of the other wheel of the two coaxial wheels gradually decreases.

[0127] Due to the coaxial wheel power transmission coupling differential, the torque output by the drive motor is more allocated to the slipping wheel, and the torque of the wheel on the high adhesion side is reduced. Therefore, it is necessary to adjust the torque and braking force distribution of the left and right wheels so that the vehicle can obtain sufficient driving force and give full play to the maximum adhesion of each wheel to get out of trouble. In some traditional cars, the rotation speed of the coaxial wheels can be made the same by setting a differential lock, so that when getting out of trouble, the slipping wheel will not be allocated too much torque. By cooperating with the drive system 30 and the braking system 60, the slip rate of the two wheels can be reduced at the same time, the rotation speed of the slipping wheel can be reduced, and the slipping wheel will not be allocated more torque, and the rotation speed of the two coaxial wheels can still be different. Unlike the differential lock, the rotation speed of the two wheels will not be made consistent blindly, thereby achieving a better effect.

[0128] In one embodiment, the magnitude of the output torque of the drive system 30 is less than or equal to the torque limit.

[0129] In the process of getting out of trouble on the spot, because of the large torque demand, in the process of controlling the torque of the drive motor 50, it is also necessary to safely limit the final output torque. The torque limit needs to consider the external characteristic limit of the drive motor 50, the maximum discharge capacity limit of the power battery, and the controllable maximum torque limit. If the output torque is too large, it may cause damage to the vehicle hardware and loss of control of the vehicle.

[0130] In one embodiment, the vehicle speed threshold is less than or equal to 15 km / h. The target slip ratio is greater than or equal to 0.1 and less than or equal to 0.3.

[0131] The thresholds in this application, such as wheel thresholds, slip thresholds, target slip rates, etc., may be pre-calibrated based on actual vehicle experiments and / or model calculations. They may be pre-set based on comprehensive consideration of vehicle requirements and vehicle performance, or may be set based on specific application scenarios, or may be adjusted upward or downward based on the pre-set values ​​to optimize the value, and the adjustment direction and the optimization value may be determined based on specific application scenarios.

[0132] According to the solution of the present application, by setting a vehicle speed threshold, it is ensured that the vehicle's on-the-spot escape strategy is applied when the vehicle is stuck, thereby avoiding false triggering situations. By setting a target slip rate, the accuracy and reliability of vehicle control are improved.

[0133] In one embodiment, the control method specifically includes: in the process of controlling the drive system 30 to output driving torque to two wheels and controlling the braking system 60 to output braking force to one wheel, when the brake pedal opening is greater than a preset opening, controlling the drive system 30 to stop outputting driving torque and controlling the braking system 60 to stop outputting braking force.

[0134] When the electric vehicle 10 is in the escape-in-place mode control, the user can quickly cancel the escape-in-place mode control by stepping on the brake pedal. When the user determines that the escape-in-place mode cannot be continued, or the escape-in-place mode is not needed, the user can quickly exit by changing the opening of the brake pedal, thereby avoiding the deterioration of road conditions or the vehicle losing control.

[0135] According to the solution of the present application, the user can exit the on-the-spot escape mode by pressing the brake pedal, which allows for a quick exit response, thereby avoiding further deterioration of road conditions and improving the controllability and safety of the vehicle.

[0136] Figure 5 A schematic diagram of the process of escaping from an emergency on the spot is given.

[0137] like Figure 5As shown, after receiving the command to start the escape-in-place mode, it is determined that the vehicle speed is in the low-speed range, and the escape-in-place control is intervened. The vehicle controller calculates the wheel adhesion and slip rate based on the high-precision collected rotational signal and output torque, and determines whether the wheels are slipping and the number of coaxial slipping wheels.

[0138] If slip is detected, the drive system 30 intervenes in the drive torque control, and tracks the optimal slip rate according to the detected motor rotation signal and the observed road adhesion, ensuring the fastest speed to reduce slip and prevent the road adhesion from deteriorating. At the same time, the braking system 60 applies braking force to the slipping side wheel according to the actual output torque ratio according to the number of coaxial slipping wheels, ensuring that the wheels on both sides of the coupling can obtain maximum adhesion.

[0139] Finally, the driving torque output by the driving motor 50 and the braking force output by the braking system 60 are safely limited. The safety torque limit mainly includes the motor external characteristic limit, the battery maximum discharge capacity limit, and the controllable maximum torque limit.

[0140] According to the solution of this application, the actual adhesion conditions of different road surfaces are quickly identified by the rotary transformer, combined with the driver's input characteristics, and according to the actual state of the vehicle, the driving torque and braking torque are quickly closed-loop controlled to achieve the human-vehicle-road fusion control scenario. The driving torque is quickly closed-looped to control the target slip rate, and the braking torque is smoothly intervened to achieve drive-brake fusion, stably and quickly match the road adhesion capabilities of each wheel, and exert the maximum escape force of the whole vehicle.

[0141] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0142] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0143] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0144] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A control method for an electric vehicle to escape from a jam, characterized in that: The control method is used to control the driving system and braking system of the electric vehicle to achieve the on-site escape of the electric vehicle when the electric vehicle is traveling at a speed lower than a preset speed after the user turns on the on-site escape mode; The control method comprises: The driving system is controlled to output driving torque to two coaxial wheels, and the braking system is controlled to output braking force to a wheel having a larger slip rate among the two wheels.

2. The control method according to claim 1, characterized in that: Controlling the braking system to output braking force to the wheel with a larger slip rate among the two wheels specifically includes: The braking system is controlled to output a braking force to the one wheel and gradually increase the braking force from a first preset value, wherein the first preset value changes with a change in a driving torque output by the driving system to the one wheel.

3. The control method according to claim 1, characterized in that: The control method specifically includes: The driving system is controlled to increase the driving torque output to the two wheels, and the braking system is controlled to increase the braking force output to the one wheel while the driving system is controlled to increase the driving torque output to the two wheels.

4. The control method according to claim 1, characterized in that: The control method specifically includes: The driving system is controlled to output a driving torque to the two coaxial wheels so as to vary with a slip rate of the other of the two wheels.

5. The control method according to claim 1, characterized in that: In the process of controlling the driving system to output driving torque to the two wheels and controlling the braking system to output braking force to the one wheel, the slip rate of the one wheel is reduced.

6. The control method according to claim 2, characterized in that: The control method further comprises: Controlling the driving torque output by the driving system to the two wheels and the braking force output by the braking system to the one wheel to increase simultaneously; After the braking force output by the braking system to the one wheel increases to a second preset value, the braking force output by the braking system to the one wheel is controlled to remain unchanged and the driving system is controlled to adjust the driving torque output to the two wheels.

7. The control method according to claim 1, characterized in that: The control method comprises: During the process of the braking system outputting braking force to the wheel with a larger slip rate among the two wheels, when the slip rate of the one wheel and the slip rate of the other wheel are both greater than the slip threshold, the braking system is controlled to reduce the braking force output to the one wheel to zero.

8. The control method according to claim 1, characterized in that: The control method specifically includes: In the process of controlling the drive system to output driving torque to the two wheels and controlling the brake system to output braking force to the one wheel, the drive torque output by the drive system to the two wheels is different from the torque indicated by the opening of the accelerator pedal and the braking force output by the brake system to the one wheel is different from the braking force indicated by the opening of the brake pedal.

9. The control method according to claim 1, characterized in that: The control method specifically includes: In the process of controlling the drive system to output drive torque to the two wheels and controlling the brake system to output braking force to the one wheel, when the brake pedal opening is greater than a preset opening, the drive system is controlled to stop outputting drive torque and the brake system is controlled to stop outputting braking force.

10. The control method according to claim 1, characterized in that: The control method specifically includes: The slip rate of one wheel of the electric vehicle is greater than a slip threshold and the slip rate of the other wheel of the two coaxial wheels is less than or equal to the slip threshold, the drive system is controlled to output drive torque to the two coaxial wheels and the brake system is controlled to output braking force to the wheel with the larger slip rate of the two wheels.

11. The control method according to claim 6, characterized in that: The control method further comprises: The driving system is controlled to adjust the output torque to reduce the slip rate of the one wheel and the other wheel of the two coaxial wheels to a target slip rate.

12. The control method according to claim 1, characterized in that: In the process of controlling the driving system to output driving torque to the two wheels and controlling the braking system to output braking force to the one wheel, the difference between the wheel speed of the one wheel and the wheel speed of the other wheel gradually decreases.

13. The control method according to any one of claims 1 to 12, characterized in that: The magnitude of the output torque of the drive system is less than or equal to the torque limit.

14. The control method according to claim 1, characterized in that: The user starting the escape-in-place mode includes: the user controlling the electric vehicle to start the escape-in-place mode by touching the central control screen of the electric vehicle or activating an escape button.

15. A vehicle controller for an electric vehicle to escape from a jam, characterized in that: The vehicle controller is configured to execute the control method according to any one of claims 1 to 14.

16. An electric vehicle, characterized in that: The electric vehicle includes the vehicle controller as claimed in claim 15, a braking system, an accelerator pedal and a brake pedal, wherein the accelerator pedal is used to indicate the torque output to the wheels of the electric vehicle, and the brake pedal is used to indicate the braking torque output to the wheels of the electric vehicle.

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