Pivot steering method and system for vehicle with four-wheel hub motor and vehicle

Abstract

The invention discloses a pivot steering method and system for a vehicle with four-wheel hub motors and the vehicle, and belongs to the technical field of automobiles. The method comprises the steps that in response to a pivot steering function starting signal of the vehicle, steering information of the vehicle is obtained, and the steering information comprises the steering angle, the current vehicle speed and the rotating direction; based on the steering angle and the current vehicle speed, whether the vehicle meets in-situ steering starting conditions or not is judged; if yes, a target wheel set is determined according to the rotation direction, and the target wheel set comprises two wheels on the same side in the vehicle; according to the target wheel set, the driving direction of each wheel edge motor in the vehicle and the wheel speed of the target wheel set are determined, and a steering instruction is generated; and controlling the vehicle to execute pivot steering based on the steering instruction. In this way, pivot steering of the vehicle in a narrow space environment can be achieved, meanwhile, the vehicle is more stable in the pivot steering process, and the driving comfort of a driver is improved.

Description

Technical Field

[0001] The present application belongs to the field of automobile technology, and specifically relates to a method, system and vehicle for steering in situ with four-wheel side motors. Background Art

[0002] With the gradual improvement of modern living standards, cars have become an indispensable means of transportation for people, and it is inevitable to steer the car during driving. However, in narrow spaces, such as narrow parking lots, alleys, etc., traditional steering methods often make it difficult to achieve convenient steering and U-turns of vehicles. Due to the minimum turning radius limit of the vehicle, the driver may need to make multiple adjustments to complete the steering operation, which not only consumes time and energy, but also increases the risk of collision. In-situ steering technology can achieve car steering in a small space.

[0003] With the development of electric vehicle technology, wheel-side motor drive technology has gradually emerged. The wheel-side motor is directly installed near the wheel and can independently control the speed and torque of each wheel, providing new possibilities for the innovation of vehicle on-the-spot steering technology. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a method for in-situ steering of a vehicle with four-wheel wheel motors, which can solve the problem that the vehicle is difficult to turn in a small space.

[0005] In order to solve the above technical problems, this application is implemented as follows: In a first aspect, an embodiment of the present application provides a method for steering a vehicle in situ with four-wheel side motors, the method comprising: In response to a signal for starting a vehicle's on-the-spot steering function, obtaining steering information of the vehicle, the steering information including a steering angle, a current vehicle speed, and a turning direction; Based on the steering angle and current vehicle speed, determine whether the vehicle meets the in-situ steering start conditions; If yes, determine the target wheel set according to the rotation direction, the target wheel set includes two wheels on the same side of the vehicle; Determine the driving direction of each wheel motor in the vehicle and the wheel speed of the target wheel group according to the target wheel group, and generate a steering instruction; The vehicle is controlled to perform pivot steering based on the steering command.

[0006] In some possible embodiments, the step of determining whether the stationary steering start condition is met based on the steering angle and the current vehicle speed specifically includes: If the current vehicle speed is less than the preset vehicle speed and the steering angle is greater than the preset steering angle, it is determined that the vehicle meets the on-the-spot steering start conditions.

[0007] In some possible embodiments, if yes, the step of determining the target wheel set according to the rotation direction specifically includes: Detect the direction of rotation of the steering wheel in the vehicle; If the rotation direction is counterclockwise, the turning direction of the vehicle is determined to be a left turn, and the left front wheel and the left rear wheel of the vehicle are determined as the first target wheel group, and the right front wheel and the right rear wheel of the vehicle are determined as the second target wheel group; If the rotation direction is clockwise, the turning direction of the vehicle is determined to be a right turn, and the right front wheel and the right rear wheel of the vehicle are determined as the first target wheel group, and the left front wheel and the left rear wheel of the vehicle are determined as the second target wheel group.

[0008] In some possible embodiments, the step of determining the driving direction of each wheel-side motor in the vehicle according to the target wheel group specifically includes: If the target wheel set is the first target wheel set, the wheel-side motor corresponding to the first target wheel set outputs a positive torque; If the target wheel set is the second target wheel set, the wheel-side motor corresponding to the second target wheel set outputs negative torque.

[0009] In some possible embodiments, the step of determining the wheel speed of the target wheel set according to the target wheel set specifically includes: The expression for determining the wheel speed of the first target wheel group is: V1=w1(R+B / 2); Wherein, V1 is the wheel speed of the first target wheel group, w1 is the wheel angular velocity of the first target wheel group, R is the turning radius of the vehicle, and B is the wheelbase of the vehicle; The expression for determining the wheel speed of the second target wheel group is: V2=w2(RB / 2); Wherein, V2 is the wheel speed of the second target wheel group, w2 is the wheel angular velocity of the second target wheel group, R is the turning radius of the vehicle, and B is the wheelbase of the vehicle.

[0010] In some possible embodiments, the process of performing on-site steering based on the steering instruction further includes: Execute the vehicle's surrounding obstacle detection instructions; If an obstacle is detected, the distance between the obstacle and the vehicle is obtained; If the distance is less than the preset distance threshold, the vehicle stops turning on the spot and sounds an alarm.

[0011] In some possible embodiments, the method for turning in situ of a vehicle with four-wheel side motors further includes: The vehicle controller obtains the vehicle's yaw rate and the output torque of each wheel motor in real time; If the yaw angular velocity is greater than a preset yaw angular velocity threshold; or the output torque is greater than the preset maximum output torque; Then the wheel side motor is controlled to reduce the speed.

[0012] In a second aspect, an embodiment of the present application provides a vehicle in-situ steering system with four-wheel side motors, the system comprising: An acquisition module, for acquiring the vehicle's steering information in response to a vehicle's on-the-spot steering function start signal, wherein the steering information includes a steering angle, a current vehicle speed, and a turning direction; A judgment module, used to judge whether the vehicle meets the in-situ steering start condition based on the turning angle and the current vehicle speed; A first determination module is used to determine a target wheel group according to a rotation direction, where the target wheel group includes two wheels on the same side of the vehicle; The second determination module is used to determine the driving direction of each wheel side motor in the vehicle and the wheel speed of the target wheel group according to the target wheel group, and generate a steering instruction; The control module is used to control the vehicle to perform on-the-spot steering based on a steering instruction.

[0013] In a third aspect, an embodiment of the present application provides a vehicle comprising a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction, when executed by the processor, implements the steps of the method of the first aspect.

[0014] In a fourth aspect, an embodiment of the present application provides a readable storage medium, on which a program or instruction is stored, and when the program or instruction is executed by a processor, the steps of the method of the first aspect are implemented.

[0015] In the embodiment of the present application, by sending a signal to turn on the spot to the vehicle, the vehicle controller system responds quickly and obtains the steering information of the vehicle, the steering information including the steering angle, the current vehicle speed and the turning direction, so as to facilitate the subsequent execution of judging the conditions for turning on the spot of the vehicle; based on the turning direction and the current vehicle speed in the steering information obtained above, it is judged whether the current vehicle speed is less than the preset vehicle speed and whether the steering angle is greater than the preset steering angle. If not, the turning on the spot is not started, so as to prevent the vehicle from starting the turning on the spot due to excessive speed, causing serious damage to the tires, suspension system and transmission system of the vehicle, and also avoiding traffic accidents caused by improper operation, thereby improving the reliability and safety of the vehicle's turning on the spot function and ensuring the safety of the vehicle and personnel; if the conditions for turning on the spot are met, it is determined according to the direction of rotation. The first target wheel group and the second target wheel group are convenient for applying driving forces in different directions to the wheels to realize the on-site steering of the vehicle, so that when the vehicle turns on the spot, the power can be concentrated and reasonably distributed to the target wheel group, thereby improving the efficiency and accuracy of the steering; according to the target wheel group, the driving direction and wheel speed of each wheel-side motor in the vehicle are determined, a steering instruction is generated, and sent to the wheel-side motor controller to realize the on-site steering of the vehicle, thereby reducing the shaking and instability during the steering process and improving the user experience; based on the steering instruction, the vehicle is controlled to perform on-site steering, and after receiving the steering instruction, the wheel-side motor controller quickly adjusts the working state of the wheel-side motor, and drives the wheel to rotate according to the driving direction and speed requirements in the instruction, thereby realizing the precise control of the on-site steering of the vehicle, and enabling the vehicle to flexibly turn in a complex environment. The method realizes the on-site steering of a vehicle with four-wheel wheel-side motors in a narrow space environment, and makes the vehicle more stable during the on-site steering process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of a method for in-situ steering of a vehicle with four-wheel side motors provided in some embodiments of the present application; Figure 2 is a schematic diagram of a method for in-situ steering of a vehicle with four-wheel side motors provided in some embodiments of the present application; Figure 3 It is a structural block diagram of a vehicle in-situ steering system with four-wheel side motors provided in some embodiments of the present application; Figure 4 This is a structural block diagram of a vehicle provided in some embodiments of the present application. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here. In addition, the "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally represents that the objects associated with each other are in an "or" relationship.

[0019] The method for in-situ steering of a vehicle with four-wheel wheel motors provided in the embodiment of the present application will be described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0020] It should be noted that the vehicle on-the-spot steering method with four-wheel wheel-side motors provided in this embodiment can be applied to electric vehicles, hybrid vehicles and traditional fuel vehicles. The vehicle control unit (VCU) of the vehicle can be used to achieve on-the-spot steering. The VCU can coordinate and manage various systems and functions of the vehicle, including the power system, transmission system, braking system, steering system, etc., and control the operating state of the vehicle by receiving sensor signals and driver input to ensure the safe and efficient operation of the vehicle.

[0021] See also Figure 1 , shown is a method for on-the-spot steering of a vehicle with four-wheel wheel motors provided in the first aspect of an embodiment of the present application. The method may include but is not limited to steps S101 to S105.

[0022] S101: In response to a vehicle's on-the-spot steering function start signal, obtaining the vehicle's steering information, the steering information including the steering angle, the current vehicle speed and the turning direction.

[0023] In this embodiment, an on-board IVI screen is provided in the vehicle. When the driver clicks the soft switch on the on-board IVI screen to start the on-site steering, the start signal is transmitted to the vehicle's VCU in the form of an electrical signal through the CAN bus (Controller Area Network, hereinafter referred to as CAN) inside the vehicle. The acquisition of steering angle information can be achieved through a high-precision angle sensor installed on the steering column. The sensor adopts the magnetoresistive principle and can accurately sense the rotation angle of the steering column and convert it into a corresponding analog voltage signal. After the analog signal is processed by the signal conditioning circuit, it is converted into a digital signal by the analog-to-digital converter and transmitted to the VCU. When the driver turns the steering wheel, the angle sensor receives the signal and transmits it to the VCU, which can accurately obtain the current steering angle, which is the angle formed by the center line when the front wheels of the car are turned and the front wheels are not deflected. The current speed information of the vehicle is obtained through the VCU of the vehicle. The VCU obtains the current speed of the vehicle by receiving the accelerator pedal opening signal and the wheel radius signal. The direction of rotation information is obtained through the direction recognition sensor installed in the vehicle steering system. It can detect whether the steering wheel is turning clockwise or counterclockwise. The sensor uses the Hall effect principle to determine the direction of rotation by detecting the change in the direction of the magnetic field. When the driver turns the steering wheel, the direction recognition sensor generates a corresponding electrical signal, which is transmitted to the VCU via the CAN bus, so that the VCU can determine the direction of rotation of the vehicle. The steering information includes the steering angle, current vehicle speed and direction of rotation, which can provide a data basis for the subsequent judgment of the in-situ turning conditions.

[0024] S102: Based on the steering angle and the current vehicle speed, determine whether the vehicle meets the on-site steering start condition.

[0025] In this embodiment, after the VCU obtains the steering angle and the current vehicle speed, the VCU of the vehicle performs the on-site steering judgment step to determine whether the vehicle meets the on-site steering start conditions. Inside the VCU of the vehicle, the vehicle speed threshold and the steering angle threshold can be pre-set. These thresholds are obtained through a large number of experimental tests and simulation analyses, and fully consider factors such as the vehicle's power performance and safety factors. When the VCU receives the steering angle signal and the current vehicle speed signal from the angle sensor, it begins to make a judgment. For example, the vehicle speed threshold for on-site steering start is set to 10km / h, and the steering angle threshold is set to 90%. If the current vehicle speed is lower than 10km / h and the steering angle is higher than 90%, the VCU will determine that the vehicle meets the basic conditions for on-site steering start. In order to ensure safety and vehicle performance, the VCU can perform a series of additional condition judgments, such as detecting the vehicle's power system status, including the vehicle's battery power or fuel level, to ensure that the vehicle has sufficient power or fuel for on-site steering.

[0026] S103: If yes, determine a target wheel set according to the rotation direction, where the target wheel set includes two wheels on the same side of the vehicle.

[0027] See also Figure 2 , T is the direction of vehicle rotation, and F is the driving direction. In this embodiment, if the vehicle meets the start-up conditions for turning in place, the target wheel group is determined according to the direction of rotation. The direction recognition sensor monitors the direction of rotation of the steering wheel in real time and transmits the rotation direction information to the VCU in the form of an electrical signal. If the steering wheel turns clockwise, it is determined that the vehicle needs to turn in place to the right. At this time, the VCU will determine the two wheels on the left side of the vehicle as the first target wheel group, and the two wheels on the right side of the vehicle as the second target wheel group; conversely, if the steering wheel turns counterclockwise, that is, it is determined that the vehicle needs to turn in place to the left, then the two wheels on the right side become the first target wheel group, and the two wheels on the left side of the vehicle are determined as the second target wheel group. After meeting the start-up conditions for turning in place, the vehicle can quickly and accurately determine the target wheel group according to the direction of rotation. Different target wheel groups can provide clear execution objects and precise control basis for subsequent turning in place.

[0028] S104: determining the driving direction of each wheel motor in the vehicle and the wheel speed of the target wheel group according to the target wheel group, and generating a steering instruction; In this embodiment, the driving direction of each wheel side motor in the vehicle and the wheel speed of the target wheel group are determined according to the target wheel group, and a steering instruction is generated. Take the vehicle turning to the left in situ as an example, at this time, the two wheels on the left are the first target wheel group. The VCU calculates the wheel speed of each target wheel group through an algorithm. To achieve the in situ turning, the two wheels on the left need a backward driving force, and the rotation speed of the two wheels on the left is consistent, while the two wheels on the right need a forward driving force, and the rotation speed of the two wheels on the right is consistent. In the process of turning in situ, the outer wheel needs to travel a larger circumferential distance, and the inner wheel travels a smaller circumferential distance, and the rotation of the vehicle around the center is achieved by rotating in opposite directions. For the calculation of the wheel speed, the ECU will accurately calculate the wheel speed of each target wheel group in the target wheel group according to the preset in situ turning radius and turning speed requirements of the vehicle, combined with the radius parameters of the wheel, and generate a steering instruction to send to the wheel side motor of each wheel. The vehicle can accurately determine the driving direction of each wheel side motor and the wheel speed of the target wheel group according to the target wheel group, and generate an effective steering instruction to achieve efficient and stable in situ turning of the vehicle.

[0029] S105: Controlling the vehicle to perform on-the-spot steering based on the steering instruction.

[0030] In this embodiment, in the step of controlling the vehicle to perform on-the-spot turning based on the steering command, after receiving the on-the-spot turning command sent by the VCU, the wheel-side motor determines the driving direction and target wheel speed of each wheel-side motor, and applies corresponding driving force to the wheel to enable the vehicle to complete the on-the-spot turning. During the entire on-the-spot turning process, the vehicle's instrument panel and information display screen can provide the driver with real-time feedback on the vehicle's steering status, such as steering angle, wheel speed and other information, so that the driver can intuitively understand the vehicle's steering status. It is possible to efficiently, smoothly and safely perform on-the-spot turning operations based on steering commands, meeting the driver's on-the-spot turning needs in a narrow environment.

[0031] In some embodiments, based on the steering angle and the current vehicle speed, the step of determining whether the on-the-spot steering start conditions are met specifically includes: if the current vehicle speed is less than a preset vehicle speed and the steering angle is greater than a preset steering angle, then determining that the vehicle meets the on-the-spot steering start conditions.

[0032] In this embodiment, the vehicle has a vehicle speed sensor and a steering angle sensor. The vehicle speed sensor is installed near the wheel axle of the wheel. Through the principle of electromagnetic induction, it senses the rotation frequency of the wheel and converts it into an electrical signal. Every time the wheel rotates, the sensor will generate a pulse signal, which is transmitted to the vehicle controller VCU of the vehicle. The parameters such as the wheel radius are pre-set inside the VCU, and the current vehicle speed is calculated by calculating the number of pulses received per unit time. The steering angle sensor is installed on the steering column and can sense the rotation angle of the steering column. When the driver turns the steering wheel, the steering column drives the sensing element inside the steering angle sensor to change its angle, thereby changing the resistance value of the steering angle sensor. The steering angle sensor converts the resistance change into a corresponding voltage signal output. After filtering, amplification and other processing, the voltage signal is converted into a digital signal and transmitted to the VCU. Inside the VCU, the preset vehicle speed and preset steering angle are pre-stored. When the vehicle receives the start signal of the in-situ steering function, the VCU quickly reads the data from the vehicle speed sensor and the steering angle sensor. The preset vehicle speed is set to 10km / h, and the preset steering angle is set to 90%. If the current vehicle speed detected by the vehicle speed sensor is less than 10km / h and the steering angle feedback by the steering angle sensor is greater than 90%, the VCU determines that the vehicle meets the conditions for starting in-place steering.

[0033] It is understandable that when the vehicle is on a slippery road, the friction between the wheels and the ground is reduced. Even if the vehicle's current speed and steering angle meet the conditions for turning in place, the wheels may slip during turning in place due to insufficient friction, affecting the steering effect and even causing danger. Therefore, the VCU will also obtain the vehicle's tire pressure sensor data and the acceleration sensor data installed on the bottom of the vehicle body in real time. When it is detected that the road is slippery or the vehicle's posture is unstable, the VCU will appropriately adjust the thresholds of the preset speed and preset steering angle, and improve the standards for the conditions for starting turning in place to ensure that the vehicle can turn in place under the premise of safety.

[0034] In some embodiments, if so, the step of determining the target wheel group according to the rotation direction specifically includes: detecting the rotation direction of the steering wheel in the vehicle; if the rotation direction is counterclockwise, it is determined that the steering direction of the vehicle is a left turn, and the left front wheel and left rear wheel of the vehicle are determined as the first target wheel group, and the right front wheel and right rear wheel of the vehicle are determined as the second target wheel group; if the rotation direction is clockwise, it is determined that the steering direction of the vehicle is a right turn, and the right front wheel and right rear wheel of the vehicle are determined as the first target wheel group, and the left front wheel and left rear wheel of the vehicle are the second target wheel group.

[0035] In this embodiment, after VCU receives the signal of steering angle sensor, the signal is analyzed and processed. If the direction of rotation of the steering wheel is detected to be counterclockwise, VCU determines that the steering direction of the vehicle is left turn according to the preset logic. At this time, VCU sends instructions to the vehicle chassis control system and the wheel side motor control system through the internal communication bus, and the left front wheel and the left rear wheel of the vehicle are determined as the first target wheel group, and the right front wheel and the right rear wheel of the vehicle are marked as the second target wheel group. On the contrary, if VCU detects that the direction of rotation of the steering wheel is clockwise, it is determined that the steering direction of the vehicle is right turn. At this time, VCU can determine the right front wheel and the right rear wheel of the vehicle as the first target wheel group, and the left front wheel and the left rear wheel are determined as the second target wheel group. Similarly, this information is conveyed to each relevant control system of the vehicle through the communication bus to ensure that the subsequent steering instruction can accurately act on the corresponding wheel group.

[0036] In this embodiment, when the driver suddenly changes the direction of the steering wheel while the vehicle is turning in place, the VCU will quickly capture the signal change of the steering angle sensor, immediately stop the current in-place steering command execution, and re-determine the target wheel group according to the new rotation direction of the steering wheel. At the same time, the VCU will adjust the driving state of the wheel-side motor to avoid vehicle loss of control or wheel damage due to sudden changes in the vehicle's rotation direction.

[0037] In some embodiments, the step of determining the driving direction of each wheel-side motor in the vehicle according to the target wheel group specifically includes: if the target wheel group is the first target wheel group, the wheel-side motor corresponding to the first target wheel group outputs a positive torque; if the target wheel group is the second target wheel group, the wheel-side motor corresponding to the second target wheel group outputs a negative torque.

[0038] In this embodiment, after the target wheel group is determined, the VCU starts to perform the operation of determining the driving direction of each wheel motor according to the target wheel group. Each wheel of the vehicle is equipped with an independent wheel motor, which adopts advanced permanent magnet synchronous motor technology and has the characteristics of high efficiency and rapid response. The wheel motor can accurately transmit the torque output by the motor to the wheel to realize the driving and steering control of the vehicle. When the VCU determines that the vehicle turns left in situ, the first target wheel group is the left front wheel and the left rear wheel, and the second target wheel group is the right front wheel and the right rear wheel. The VCU calculates the positive torque required to be output by each wheel motor of the first target wheel group and the negative torque required to be output by each wheel motor of the second target wheel group through the internal motor control algorithm. Positive torque means that the motor drives the wheel to rotate forward to realize that the wheel has a forward driving force; negative torque means that the motor drives the wheel to rotate backward to realize that the wheel has a forward driving force. The VCU converts these calculation results into detailed control instructions, which are transmitted to the wheel motors corresponding to the first target wheel group and the second target wheel group through the high-speed CAN bus to realize the vehicle turning left in situ. On the contrary, if the VCU determines that the vehicle is turning left in situ, the first target wheel group is the right front wheel and the right rear wheel, and the second target wheel group is the left front wheel and the left rear wheel. The VCU also calculates the positive torque required to be output by each wheel-side motor of the first target wheel group and the negative torque required to be output by each wheel-side motor of the second target wheel group through the motor control algorithm to achieve the vehicle turning right in situ.

[0039] In some embodiments, the step of determining the wheel speed of the target wheel group based on the target wheel group specifically includes: determining the expression of the wheel speed of the first target wheel group as: V1=w1(R+B / 2); wherein V1 is the wheel speed of the first target wheel group, w is the wheel angular velocity of the first target wheel group, R is the turning radius of the vehicle, and B is the wheelbase of the vehicle; determining the expression of the wheel speed of the second target wheel group as: V2=w2(RB / 2); wherein V2 is the wheel speed of the second target wheel group, w is the wheel angular velocity of the second target wheel group, R is the turning radius of the vehicle, and B is the wheelbase of the vehicle.

[0040] In this embodiment, the parameters of the turning radius R and wheelbase B of the vehicle are stored in the database of the VCU, and can be adjusted accordingly according to different models and configurations. For example, the wheelbase of a small vehicle is relatively narrow, while the wheelbase of a large vehicle is wider, and the turning radius will also vary depending on the size and purpose of the vehicle. When the vehicle is ready to turn in place, the VCU first needs to obtain the angular velocity w1 of the wheel, which is obtained by the angular velocity sensor installed on the wheel axle. The sensor uses the principle of a gyroscope to measure the rotational angular velocity of the wheel in real time, and converts it into an electrical signal and sends it to the VCU. When the VCU determines that the first target wheel group is turning in place to the left, the first target wheel group is the left front wheel and the left rear wheel. According to the pre-set wheel speed expression, the VCU starts to calculate the wheel speed of the first target wheel group. R represents the circumferential radius traveled by the first target wheel group when turning in place to the left. Because the inner wheel travels a smaller circumferential distance during the turning process, its wheel speed is relatively low. Similarly, the second target wheel speed V2 can be calculated. After calculating the wheel speeds V1 and V2, the VCU converts this data into specific control instructions and sends them to the wheel motors corresponding to the first target wheel group and the second target wheel group through the high-speed CAN bus. After receiving the instructions, the wheel motors adjust the motor speed according to the motor's characteristic curve and current working status. The motor controller adjusts the motor speed by changing the frequency and amplitude of the three-phase current input to the motor so that its output speed matches the calculated wheel speed V1 of the first target wheel group and the wheel speed V2 of the second target wheel group.

[0041] In some embodiments, the process of executing on-the-spot turning based on the steering instruction also includes: executing the vehicle's surrounding obstacle detection instruction; if an obstacle is detected, obtaining the distance between the obstacle and the vehicle; if the distance is less than a preset distance threshold, the vehicle stops turning on the spot and issues an alarm.

[0042] In this embodiment, the vehicle can use various types of sensors for obstacle detection, including millimeter wave radar, ultrasonic sensor and camera. The millimeter wave radar is installed on the front and rear bumpers and sides of the vehicle, and uses electromagnetic waves in the millimeter wave frequency band to scan the surrounding environment. It can emit millimeter wave signals and receive reflected signals. By analyzing the time delay and frequency change of the signal, it can accurately calculate the distance, speed and angle information of the obstacle. Ultrasonic sensors are mainly distributed in the front and rear bumpers of the vehicle. They detect close obstacles by emitting and receiving ultrasonic waves. Their working principle is to use the time difference of ultrasonic waves propagating in the air to calculate the distance between the obstacle and the vehicle. The camera is installed on the front, back and both sides of the vehicle. It monitors the surrounding environment in real time through image recognition technology and can identify various types of obstacles, such as other vehicles, pedestrians, walls, etc.

[0043] In this embodiment, during the vehicle's in-situ steering process, these sensors continue to work and transmit the collected data to the VCU in real time. The VCU analyzes these data to determine whether there is an obstacle. Once an obstacle is detected, the VCU calculates the distance between the obstacle and the vehicle based on the sensor data. For millimeter-wave radar and ultrasonic sensors, the distance data measured can be directly obtained; inside the VCU, the distance threshold determined by safety assessment and testing is pre-stored. When the calculated distance between the obstacle and the vehicle is less than the preset distance threshold, the VCU immediately takes emergency measures. First, the VCU sends an instruction to stop the in-situ steering to the wheel-side motor, and stops the wheel-side motor from running by adjusting the current and voltage of the motor, so that the vehicle stops steering in-situ. At the same time, the VCU triggers the vehicle's alarm system, and a striking alarm icon will be displayed on the dashboard inside the vehicle, prompting the driver that there are obstacles around the vehicle and stopping the in-situ steering operation. At the same time, the vehicle will emit a loud alarm sound to attract the driver's attention.

[0044] In some embodiments, the method for steering in place for a vehicle with four-wheel wheel motors also includes: obtaining the vehicle's yaw rate and the output torque of each wheel motor in real time through a vehicle controller; if the yaw rate is greater than a preset yaw rate threshold; or the output torque is greater than a preset maximum output torque; then controlling the wheel motor to reduce the rotation speed.

[0045] In this embodiment, during the vehicle's on-the-spot steering process, the VCU receives data from the yaw rate sensor and the wheel-side motor torque sensor. When the yaw rate sensor detects that the yaw rate is greater than the preset yaw rate threshold, or the output torque detected by the wheel-side motor torque sensor is greater than the preset maximum output torque, the VCU starts the control mechanism. During the entire speed adjustment process, the VCU continuously monitors the yaw rate and the output torque of the wheel-side motor. When these parameters return to the normal range, the VCU stops speed adjustment and maintains the current motor speed to ensure that the vehicle can continue to complete the on-the-spot steering operation in a safe and stable state.

[0046] In the embodiment of the present application, by sending a signal to turn on the spot to the vehicle, the vehicle controller system responds quickly and obtains the steering information of the vehicle, and the steering information includes the steering angle, the current vehicle speed and the turning direction, so as to facilitate the subsequent execution of judging the conditions for turning on the spot of the vehicle; based on the turning direction and the current vehicle speed in the steering information obtained above, it is judged whether the current vehicle speed is less than the preset vehicle speed and whether the steering angle is greater than the preset steering angle. If not, the turning on the spot is not started, so as to prevent the vehicle from starting the turning on the spot due to excessive speed, causing serious damage to the tires, suspension system and transmission system of the vehicle, and also avoiding traffic accidents caused by improper operation, thereby improving the reliability and safety of the vehicle's turning on the spot function and ensuring the safety of the vehicle and personnel; if the conditions for turning on the spot are met, the vehicle is turned on according to the The direction of rotation determines the first target wheel group and the second target wheel group, which is convenient for applying driving forces in different directions to the wheels to realize the on-site steering of the vehicle, so that when the vehicle turns on the spot, the power can be concentrated and reasonably distributed to the target wheel group, thereby improving the efficiency and accuracy of steering; the driving direction and wheel speed of each wheel-side motor in the vehicle are determined according to the target wheel group, and a steering instruction is generated and sent to the wheel-side motor controller to realize the on-site steering of the vehicle, thereby reducing the shaking and instability during the steering process and improving the user experience; the vehicle is controlled to perform on-site steering based on the steering instruction. After receiving the steering instruction, the wheel-side motor controller drives the wheel to rotate according to the driving direction and speed requirements in the instruction, thereby realizing the precise control of the on-site steering of the vehicle and enabling the vehicle to flexibly turn in a complex environment. The method realizes the on-site steering of a vehicle with four-wheel wheel-side motors in a narrow space environment, and makes the vehicle more stable during the on-site steering process.

[0047] It should be noted that the method for on-the-spot steering of a vehicle with four-wheel wheel-side motors provided in the embodiment of the present application can be executed by a vehicle on-the-spot steering system with four-wheel wheel-side motors, or a control module in the system for executing the method for on-the-spot steering of a vehicle with four-wheel wheel-side motors. In the embodiment of the present application, the method for controlling on-the-spot steering of a vehicle with four-wheel wheel-side motors provided in the embodiment of the present application is explained by taking the execution of the method for on-the-spot steering of a vehicle with four-wheel wheel-side motors by an on-the-spot steering system with four-wheel wheel-side motors as an example.

[0048] See also Figure 3 In some embodiments of the present application, the vehicle in-situ steering system 300 with four-wheel side motors provided in the embodiment of the present application includes: The acquisition module 310 is used to obtain the vehicle's steering information in response to the vehicle's on-the-spot steering function start signal, where the steering information includes a steering angle, a current vehicle speed, and a turning direction; A determination module 320, for determining whether the vehicle meets the in-situ steering start condition based on the turning angle and the current vehicle speed; A first determination module 330 is used to determine a target wheel group according to the rotation direction, where the target wheel group includes two wheels on the same side of the vehicle; The second determination module 340 is used to determine the driving direction of each wheel side motor in the vehicle and the wheel speed of the target wheel group according to the target wheel group, and generate a steering instruction; The control module 350 is used to control the vehicle to perform on-the-spot steering based on the steering instruction.

[0049] The vehicle in-situ steering system with four-wheel wheel-side motors in the embodiment of the present application can be a device, or a component, integrated circuit, or chip in a terminal. The device can be a mobile electronic device or a non-mobile electronic device. Exemplarily, the mobile electronic device can be a mobile phone, a tablet computer, a laptop computer, a PDA, an in-vehicle electronic device, a wearable device, an ultra-mobile personal computer (UMPC), a netbook, or a personal digital assistant (PDA), etc. The non-mobile electronic device can be a server, a network attached storage (NAS), a personal computer (PC), a television (TV), a teller machine or a self-service machine, etc., which is not specifically limited in the embodiment of the present application.

[0050] The vehicle in-situ steering system with four-wheel side motors provided in the embodiment of the present application can achieve Figure 1 The various processes implemented by the vehicle in-situ steering system with four-wheel side motors in the method embodiment will not be repeated here to avoid repetition.

[0051] Optionally, see Figure 4 The embodiment of the present application also provides a vehicle, including a processor 401, a memory 402, and a computer program or instruction 403 stored in the memory 402 and executable on the processor 401. When the computer program or instruction 403 is executed by the processor 401, each process of the above-mentioned embodiment of the vehicle in-situ steering method with four-wheel wheel-side motors is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0052] An embodiment of the present application also provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, each process of the above-mentioned vehicle in-situ steering method embodiment with four-wheel side motors is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0053] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0054] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0055] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0056] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A method for turning in situ of a vehicle with four-wheel side motors, characterized in that: The method comprises: In response to a signal for starting a local steering function of the vehicle, obtaining steering information of the vehicle, the steering information including a steering angle, a current vehicle speed and a turning direction; Based on the steering angle and the current vehicle speed, determining whether the vehicle meets the on-site steering start condition; If yes, determining a target wheel set according to the rotation direction, the target wheel set comprising two wheels on the same side of the vehicle; Determine the driving direction of each wheel-side motor in the vehicle and the wheel speed of the target wheel group according to the target wheel group, and generate a steering instruction; The vehicle is controlled to perform pivot steering based on the steering command.

2. The method for turning in situ of a vehicle with four-wheel side motors according to claim 1, characterized in that: The step of judging whether the stationary steering start condition is met based on the steering angle and the current vehicle speed specifically includes: If the current vehicle speed is less than a preset vehicle speed and the steering angle is greater than a preset steering angle, it is determined that the vehicle meets the on-site steering start condition.

3. The method for turning in situ of a vehicle with four-wheel side motors according to claim 1, characterized in that: If so, the step of determining the target wheel set according to the rotation direction specifically includes: detecting a rotation direction of a steering wheel in the vehicle; If the rotation direction is counterclockwise, the turning direction of the vehicle is determined to be a left turn, and the left front wheel and the left rear wheel of the vehicle are determined as the first target wheel group, and the right front wheel and the right rear wheel of the vehicle are determined as the second target wheel group; If the rotation direction is clockwise, the turning direction of the vehicle is determined to be a right turn, and the right front wheel and the right rear wheel of the vehicle are determined as the first target wheel group, and the left front wheel and the left rear wheel of the vehicle are determined as the second target wheel group.

4. The method for turning in situ of a vehicle with four-wheel side motors according to claim 3, characterized in that: The step of determining the driving direction of each wheel-side motor in the vehicle according to the target wheel group specifically includes: If the target wheel set is the first target wheel set, the wheel side motor corresponding to the first target wheel set outputs a positive torque; If the target wheel set is the second target wheel set, the wheel-side motor corresponding to the second target wheel set outputs negative torque.

5. The method for turning in situ of a vehicle with four-wheel side motors according to claim 4, characterized in that: The step of determining the wheel speed of the target wheel group according to the target wheel group specifically includes: The expression for determining the wheel speed of the first target wheel group is: V1=w1(R+B / 2); Wherein, V1 is the wheel speed of the first target wheel group, w1 is the wheel angular velocity of the first target wheel group, R is the turning radius of the vehicle, and B is the wheelbase of the vehicle; The expression for determining the wheel speed of the second target wheel set is: V2=w2(RB / 2); Among them, V2 is the wheel speed of the second target wheel group, w2 is the wheel angular velocity of the second target wheel group, R is the turning radius of the vehicle, and B is the wheelbase of the vehicle.

6. The method for turning in situ of a vehicle with four-wheel side motors according to claim 1, characterized in that: The process of performing in-situ steering based on the steering instruction also includes: Executing a surrounding obstacle detection instruction of the vehicle; If the obstacle is detected, obtaining the distance between the obstacle and the vehicle; If the distance is less than a preset distance threshold, the vehicle stops turning on the spot and issues an alarm.

7. The method for in-situ steering of a vehicle with four-wheel side motors according to claim 1, characterized in that: Also includes the steps: Acquiring the yaw rate of the vehicle and the output torque of each wheel motor in real time through a vehicle controller; If the yaw angular velocity is greater than a preset yaw angular velocity threshold; or the output torque is greater than a preset maximum output torque; Then the wheel side motor is controlled to reduce the rotation speed.

8. A vehicle in-situ steering system with four-wheel side motors, characterized in that: The system comprises: an acquisition module, configured to acquire the steering information of the vehicle in response to a signal for starting the on-the-spot steering function of the vehicle, wherein the steering information includes a steering angle, a current vehicle speed and a turning direction; A judgment module, used for judging whether the vehicle meets the in-situ steering start condition based on the rotation angle and the current vehicle speed; A first determination module is used to determine a target wheel group according to the rotation direction, wherein the target wheel group includes two wheels on the same side of the vehicle; A second determination module is used to determine the driving direction of each wheel-side motor in the vehicle and the wheel speed of the target wheel group according to the target wheel group, and generate a steering instruction; A control module is used to control the vehicle to perform on-the-spot steering based on the steering instruction.

9. A vehicle, characterized in that: It includes a processor, a memory, and a program or instruction stored in the memory and executable on the processor. When the program or instruction is executed by the processor, the steps of the method for in-situ steering of a vehicle with four-wheel wheel-side motors as described in claims 1-7 are implemented.

10. A readable storage medium, characterized in that: The readable storage medium stores programs or instructions, and when the programs or instructions are executed by the processor, the steps of the method for in-situ steering of a vehicle with four-wheel side motors as described in claims 1-7 are implemented.

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