Synchronous control method and system for linear motion of four-wheel independent drive electric vehicle

Abstract

The invention provides a linear motion synchronous control method and system for a four-wheel independent drive electric vehicle, and the method comprises the steps: taking a speed difference value of the left and right wheels of the electric vehicle as a reference variable, adding the speed difference value into the closed-loop control of a motor, calculating a difference value signal through a PI controller, and outputting a control signal; the speed difference value between a front wheel set and a rear wheel set of the electric automobile is used as a controlled variable to be controlled, the differential speed between the front wheel set and the rear wheel set is restrained, and cooperation of the speeds of the four wheels is achieved through independent PI control over all driving wheels; establishing a left and right wheel direct current motor deviation control simulation model, and verifying the feasibility of a left and right wheel synchronous control algorithm based on speed deviation; and establishing a linear control simulation model of the four-wheel independent drive electric vehicle, and verifying the feasibility of a front and rear wheel set synchronous control algorithm based on speed deviation. The system comprises an intra-wheel-set synchronous control module, an inter-wheel-set synchronous control module and a motion simulation verification module. According to the invention, the stability and the high efficiency during linear driving are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric vehicle control, and particularly relates to a four-wheel independent drive electric vehicle linear motion synchronization control method and system. BACKGROUND

[0002] With the rapid development of China's economy, people's car ownership rate is also rising, but more and more fuel cars also bring us a series of problems such as environmental pollution and energy shortage. With the continuous development of automobile technology, four-wheel independent drive electric vehicles gradually become people's more intelligent and environmentally friendly choice. Because it has a more flexible control method for consumers to bring a more comfortable driving experience. With the development of modern control theory and related technology, more lightweight, intelligent and energy-saving pure electric vehicles are increasingly becoming people's choice. Electric vehicles use electric motors as the driving force and batteries as the energy supply source, which can well meet the requirements of safety, energy saving and environmental protection. Four-wheel independent drive intelligent vehicles are vehicles with independent control of driving force and steering ability for each wheel, and their design aims to improve the maneuverability, handling and stability of vehicles, providing important technical support for the development of autonomous driving and intelligent transportation systems. The main features of four-wheel independent drive intelligent vehicles include: each wheel of the intelligent vehicle is equipped with an independent electric drive system, which can independently control the speed and steering angle of each wheel, thereby achieving precise vehicle control and steering. Four-wheel independent drive systems can achieve more flexible vehicle turning and steering, greatly improving the maneuverability and handling of the vehicle, allowing it to travel in narrow roads or complex environments. By adjusting the driving force and steering angle of each wheel in real time, the intelligent vehicle can more accurately control the vehicle's attitude and stability, improving the stability and safety of the vehicle at high speeds and in emergency situations. Four-wheel independent drive intelligent vehicles are intelligent mobile platforms with four independent drive wheels, each driven by an independent motor, with high maneuverability and flexibility; this vehicle structure allows each wheel to be independently controlled in terms of speed and direction, enabling complex movements and operations. Here are some features and advantages of four-wheel independent drive intelligent vehicles: high maneuverability: each wheel can be independently driven, giving the vehicle good maneuverability and flexibility. It can achieve a variety of complex movements such as translation, rotation, turning, etc., suitable for a variety of different application scenarios. Although the four-wheel independent drive intelligent vehicle control system has made some achievements, there are still some challenges and problems to be solved. For example, improving the reliability and stability of the system, reducing costs and improving production efficiency, etc. In addition, with the continuous progress of technology and the changing market, future research also needs to focus on new technological trends and market demands to promote the continuous development and innovation of the four-wheel independent drive intelligent vehicle control system.

[0003] Prior art one, application number: CN202211639317.0 discloses an automatic driving end-to-end longitudinal motion control method based on deep reinforcement learning, a reinforcement learning model based on Markov decision process is established, and model training is realized in a simulation environment. After training in the cloud, real vehicle deployment is carried out, the vehicle-mounted domain controller takes the perception information as input in real time, and outputs the instructions of motor and brake torque, realizing the end-to-end longitudinal motion control of intelligent networked electric vehicles. For reinforcement learning model training initialization, the pre-training results of hierarchical control strategy are used, so that the training is greatly accelerated in the form of imitation learning, and the performance of the trained model is significantly improved by combining multiple target optimization. Although the vehicle itself completes control decision when end-to-end control fails, and the driver takes over after all automatic driving strategies fail, so as to fully guarantee the control stability and driving safety with redundant mechanism; but it only controls longitudinally, without independent control of the four wheels of the vehicle, resulting in poor straight line motion retention of the vehicle during driving.

[0004] Prior art two, application number: CN202410036318.9 discloses a man-machine cooperative motion control method for distributed drive and rear wheel steering electric vehicles, including the following steps: identifying the driver's input steering information as steering intention result; designing a vehicle reference model, designing an expected reference state; designing a drive-steering cooperative controller for distributed drive and rear wheel steering electric vehicles, including an upper controller and a lower controller; solving the upper controller to obtain the optimal additional rear wheel angle and additional yaw moment; distributing the optimal additional yaw moment through the lower controller to obtain four-wheel additional torque; sending the four-wheel additional torque as control instructions to the electric vehicle four-wheel hub motor to realize cooperative control of the vehicle. Although compared with the prior art, it has the advantages of matching the vehicle control target with the driver's operation, improving the man-machine cooperative motion control performance of the driver-vehicle closed loop, etc.; but it lacks technical means for four-wheel control of electric vehicles, and does not greatly assist the straight line driving of electric vehicles, and its straight line motion control performance needs to be further improved.

[0005] The prior art three, application number: CN202410425867.5 discloses a motor control method and device of an electric vehicle, comprising: obtaining vehicle actual motion information of the electric vehicle in the driving process through a vehicle-mounted sensor; performing vehicle upper layer thrust distribution through a vehicle dynamics model and the vehicle actual motion information, determining the expected acceleration corresponding to each motor; determining the control signal of each motor according to the expected acceleration and a PID controller; processing the control signal based on a unified frequency domain characteristic compensator to obtain the target control signal corresponding to each motor; and performing motor control on each motor through the target control signal. Although the two motor frequency domain characteristics can be adjusted to be consistent, the consistency of the two motor performances in the vehicle motion process is ensured, thereby improving the stability of the vehicle motor control, reducing the influence of the imbalance of the vehicle power system on the vehicle motion linearity, and simultaneously, the energy loss required during the vehicle adjustment can be saved, and the use experience is improved; however, the motor is independently controlled, and the control of four-wheel independent driving is not realized, so that the straight line motion performance has certain limitations.

[0006] At present, the prior art one, the prior art two and the prior art three lack the control technology means of four-wheel independent driving of an electric vehicle, so that the straight line running control precision of the electric vehicle needs to be further improved. Therefore, the present application provides a four-wheel independent driving electric vehicle straight line motion synchronous control method and system. SUMMARY

[0007] In order to solve the above technical problems, the present application provides a four-wheel independent driving electric vehicle straight line motion synchronous control method, comprising the following steps:

[0008] The speed difference value of the left and right wheels of the electric vehicle is added as a reference variable to the closed loop control of the motor, the difference value signal is calculated by a PI controller and the control signal is outputted, so that the rotation speed of the left and right drive wheels is maximally approximated;

[0009] The speed difference value between the front and rear wheel groups of the electric vehicle is controlled as a controlled variable to suppress the differential speed between the front and rear wheel groups, and the four-wheel speed cooperation is realized through the independent PI control of each drive wheel;

[0010] A left and right wheel DC motor deviation control simulation model is built to verify the feasibility of the left and right wheel synchronous control algorithm based on the speed deviation; a left and right wheel speed coupling term is added to the DC motor model, and the synchronous control of the left and right wheels is realized through a PI controller; a four-wheel independent driving electric vehicle straight line control simulation model is built in Simulink to verify the feasibility of the front and rear wheel group synchronous control algorithm based on the speed deviation.

[0011] Optionally, the process of calculating the difference value signal by the PI controller and outputting the control signal comprises the following steps:

[0012] The speed difference between the left and right wheels is calculated, and the speed difference is used as an input signal of a PI controller. A proportional gain is multiplied by the speed difference to obtain an output of a proportional part. An integral gain is multiplied by an integral of the speed difference to obtain an output of an integral part.

[0013] The outputs of the proportional part and the integral part are added to obtain a total output signal of the PI controller. The total output signal is used as a control signal and is applied to motor controllers of the left and right wheels. The motor controllers of the left and right wheels adjust the output torque or speed of the motors according to the received control signal to reduce the speed difference. Through continuous adjustment, the speeds of the left and right wheels tend to be consistent, achieving maximum approximation.

[0014] The speed difference is continuously detected and fed back to the PI controller, and the PI controller continuously adjusts the control output according to the feedback signal.

[0015] Optionally, the process of adjusting the output torque or speed of the motor includes the following steps:

[0016] After receiving the control signal transmitted by the PI controller, the motor controller analyzes the strength of the signal. According to the analyzed signal strength, the motor controller sets a reference torque or speed, which is calculated according to the current running state of the motor and the target speed difference.

[0017] If the signal strength indicates that the torque needs to be adjusted, the motor controller adjusts the electromagnetic torque of the motor by changing the current or voltage of the motor. If the signal strength indicates that the speed needs to be adjusted, the motor controller adjusts the speed of the motor by changing the power supply frequency or voltage of the motor.

[0018] The motor controller continuously monitors the actual output torque or speed of the motor and compares it with the set reference value. If there is a deviation, the motor controller fine-tunes the current, voltage, or frequency according to the size and direction of the deviation. When the output torque or speed of the motor reaches the expected value, the motor controller enters a steady-state maintenance mode, continuously monitoring and fine-tuning the running state of the motor.

[0019] Optionally, the process of adjusting the torque and speed includes the following steps:

[0020] The difference between the target torque and the actual torque is calculated. The difference between the target torque and the actual torque is multiplied by the proportional gain, and the integral of the difference is multiplied by the integral gain to obtain the torque signal strength.

[0021] The difference between the target speed and the actual speed is calculated, and the proportional gain and the integral gain are determined. The difference between the target speed and the actual speed is multiplied by the proportional gain, and the integral of the difference is multiplied by the integral gain to obtain the speed signal strength.

[0022] Comparing the torque signal strength and the speed signal strength; if the torque signal strength is greater than the speed signal strength, and torque control is the current priority, then the torque will be adjusted; otherwise, if the speed signal strength is greater than the torque signal strength, and speed control is the current priority, then the speed will be adjusted.

[0023] Optionally, the process of achieving the cooperation of the four-wheel speed through independent PI control of each drive wheel includes the following steps:

[0024] Through the sensors installed on each wheel, real-time speed data of the front and rear wheel groups are obtained; the speed difference between the front and rear wheel groups is calculated, and the difference is the control variable, reflecting the possible speed inconsistency between the front and rear wheel groups during driving;

[0025] Based on the calculated speed difference, a corresponding control signal is generated through multiple PI controllers; the PI controller adjusts the motor output of each drive wheel according to the size and change trend of the speed difference, and suppresses the speed difference between the front and rear wheel groups;

[0026] The motor of each drive wheel receives the control signal from the PI controller and adjusts its speed according to the control signal, and the speed of the front and rear wheel groups is effectively cooperatively controlled; the speed of the front and rear wheel groups is continuously monitored, and the parameters of the PI controller are dynamically adjusted as needed.

[0027] Optionally, the process of adjusting the motor output of each drive wheel includes the following steps:

[0028] Real-time monitoring of the speed of the front and rear wheel groups is performed, and the speed difference is calculated;

[0029] The calculated speed difference is multiplied by a proportional gain to obtain a proportional control signal, and the proportional gain is adjusted according to the dynamic characteristics of the system and the desired response speed;

[0030] The generated proportional control signal acts on the motor to adjust the output torque of the motor to reduce the speed difference; the proportional control signal will be converted into a corresponding voltage or current signal by the motor controller to drive the motor to adjust its output torque.

[0031] Optionally, the process of obtaining the proportional control signal includes the following steps:

[0032] A reference model is set, which is an ideal linear system; the controller of the motor is composed of a feedforward controller and a feedback controller; the feedforward controller is used to compensate for the dynamic characteristics, and the feedback controller is used to reduce the error;

[0033] An adaptive law is designed using Lyapunov stability theory to obtain the rate of change of the parameters of the feedforward controller and the feedback controller;

[0034] The closed-loop transfer function considers the effects of the feedforward controller and the feedback controller, and shows the relationship between the output and the input; by adjusting the controller parameters, the dynamic response can be optimized.

[0035] Optionally, the process of building a four-wheel independent drive electric vehicle straight line control simulation model in Simulink includes the following steps:

[0036] Open Simulink and create a new model file, find and add 4 DC motor modules in the Simulink library browser, which represent the four drive wheels of the electric vehicle; configure the corresponding parameters for each motor module;

[0037] Add a PI controller to each motor module to control the speed of the motor; the PI controller will adjust the output of the motor according to the speed difference signal; calculate the speed difference between the front and rear wheel groups and input it as a control signal into the corresponding PI controller to suppress the differential speed between the front and rear wheel groups; add a drive and set value module to set the target speed of each motor; according to the straight line motion requirements of the vehicle, provide the corresponding speed set value for each motor;

[0038] Connect the speed output of each motor to the corresponding PI controller, connect the output of the PI controller to the input of the motor, and connect the output of the front and rear signal processing module to the corresponding PI controller; connect the output of the drive and set value module to the speed set end of each motor; set the simulation time and step parameters, run the simulation model, and observe the speed synchronization of the four-wheel independent drive electric vehicle in straight line motion.

[0039] Optionally, the visualization process of running the simulation model includes the following steps:

[0040] Connect the speed output signal of each motor to the corresponding oscilloscope module, and connect the speed output signal of all motors to a multi-input oscilloscope module;

[0041] Configure the parameters of the oscilloscope module, set the time range and display mode, etc.

[0042] Run the simulation and observe the results, display the speed curve of each motor in real time, check whether the speed of each motor is synchronized, and whether there is a significant speed difference.

[0043] The four-wheel independent drive electric vehicle straight line motion synchronization control system provided by the application comprises:

[0044] The intra-wheel group synchronization control module is responsible for adding the speed difference between the left and right wheels as a reference variable to the closed-loop control of the motor, calculating the difference signal through the PI controller and outputting the control signal, so that the rotational speed of the left and right drive wheels is maximally approximated.

[0045] The wheel group synchronization control module is responsible for controlling the speed difference between the front and rear wheel groups as the controlled variable, suppressing the differential speed between the front and rear wheel groups, and realizing the cooperation of the four-wheel speed through the independent PI control of each driving wheel.

[0046] The motion simulation verification module is responsible for building a left and right wheel DC motor deviation control simulation model, verifying the feasibility of the left and right wheel synchronization control algorithm based on speed deviation, adding a left and right wheel speed coupling term to the DC motor model, and realizing the cooperative control of the left and right wheels through the PI controller, and building a four-wheel independent drive electric vehicle straight line control simulation model in Simulink to verify the feasibility of the front and rear wheel group synchronization control algorithm based on speed deviation.

[0047] The left and right wheel speed difference control of the present application can adjust the motor control signal in real time by taking the speed difference of the left and right wheels as the reference variable, so that the rotation speed of the left and right driving wheels is as close as possible, which helps to reduce the side slip and deviation of the vehicle when driving straight, and improves the stability of driving. The PI controller can quickly respond to the change of the speed difference and output adjustment signal in time to ensure that the vehicle can quickly adapt to the road conditions and maintain straight driving. The front and rear wheel group speed difference control can effectively suppress the differential speed between the front and rear wheel groups by controlling the speed difference between the front and rear wheel groups, and ensure the overall coordination of the vehicle when driving straight. The independent PI controller of each driving wheel can realize the cooperation of the four-wheel speed, ensure that each wheel can operate according to the predetermined speed, and improve the overall control precision. The simulation model verification can verify the feasibility of the left and right wheel synchronization control algorithm based on speed deviation by building a left and right wheel DC motor deviation control simulation model, and ensure the effectiveness of the algorithm in practical application. The four-wheel independent drive electric vehicle straight line control simulation model can be built in Simulink to further optimize the front and rear wheel group synchronization control algorithm and improve the precision and reliability of the control strategy.

[0048] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and attained by the structure particularly pointed out in the written description and the accompanying drawings.

[0049] The technical solutions of the present application will be further described in detail below with the help of the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0050] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation on the present application. In the drawings:

[0051] Figure 1Flow chart for the straight line motion synchronous control method of the four-wheel independent drive electric vehicle in embodiment 1 of the present application;

[0052] Figure 2 Process chart for the process of calculating the difference signal and outputting the control signal by the PI controller in embodiment 2 of the present application;

[0053] Figure 3 Process chart for the process of adjusting the output torque or rotating speed of the motor in embodiment 3 of the present application;

[0054] Figure 4 Process chart for the process of adjusting the torque and rotating speed in embodiment 4 of the present application;

[0055] Figure 5 Process chart for the process of realizing the coordination of the four-wheel speed by the PI control of each drive wheel in embodiment 5 of the present application;

[0056] Figure 6 Process chart for the process of adjusting the output of the motor of each drive wheel in embodiment 6 of the present application;

[0057] Figure 7 Process chart for the process of obtaining the proportional control signal in embodiment 7 of the present application;

[0058] Figure 8 Process chart for the process of building the straight line control simulation model of the four-wheel independent drive electric vehicle in Simulink in embodiment 8 of the present application;

[0059] Figure 9 Visual process chart for the process of running the simulation model in embodiment 9 of the present application;

[0060] Figure 10 Block diagram of the straight line motion synchronous control system of the four-wheel independent drive electric vehicle in embodiment 10 of the present application;

[0061] Figure 11 Simulation model schematic diagram of the left-right coordination control PI controller in embodiment 10 of the present application;

[0062] Figure 12 Straight line control model schematic diagram of the four-wheel independent drive electric vehicle in embodiment 10 of the present application. DETAILED DESCRIPTION

[0063] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, and it should be understood that the preferred embodiments described herein are only used to explain and illustrate the present application, and are not used to limit the present application.

[0064] The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments of the present application. As used in the description of the embodiments of the present application, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It also will be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0065] The following description refers to the accompanying drawings. Unless otherwise noted, like elements in different drawings represent the same or similar elements. The following description of the example embodiments is not meant to represent all embodiments in accordance with the present application. Rather, it is an example of devices and methods in accordance with some aspects of the present application. In the description of the present application, it is to be understood that the terms "first", "second", "third", etc. are used herein only to distinguish one element from another, and do not necessarily have to describe a particular sequential or chronological order, nor are they used to indicate or imply relative importance of the elements so qualified. The specific meaning of the above terms in the present application can be understood by the person of ordinary skill in the art according to the specific circumstances.

[0066] Embodiment 1: As shown in the figure, the embodiments of the present application provide a four-wheel independent drive electric vehicle straight line motion synchronous control method, comprising the following steps: Figure 1

[0067] S100: The speed difference of the left and right wheels of the electric vehicle is added as a reference variable to the closed loop control of the motor, the difference signal is calculated by the PI controller and the control signal is output, so that the rotation speed of the left and right drive wheels is maximally approximated;

[0068] S200: The speed difference between the front and rear wheel groups of the electric vehicle is controlled as a controlled variable, the differential speed between the front and rear wheel groups is suppressed, and the cooperation of the four-wheel speed is realized through the independent PI control of each drive wheel;

[0069] S300: Build a left and right wheel DC motor deviation control simulation model to verify the feasibility of the left and right wheel synchronous control algorithm based on speed deviation; by adding a left and right wheel speed coupling term to the DC motor model, and through the PI controller to realize the cooperative control of the left and right wheels; build a four-wheel independent drive electric vehicle straight line control simulation model in Simulink to verify the feasibility of the front and rear wheel group synchronous control algorithm based on speed deviation.

[0070] ​The working principle and beneficial effects of the above technical solution are: first, the speed difference of the left and right wheels of the electric vehicle is added as a reference variable to the closed-loop control of the motor, the PI controller calculates the difference signal and outputs the control signal, so that the rotation speed of the left and right drive wheels is maximally approximated; second, the speed difference between the front and rear wheel groups of the electric vehicle is controlled as a controlled variable to suppress the differential speed between the front and rear wheel groups, and the four-wheel speed is coordinated through independent PI control of each drive wheel; finally, a left and right wheel DC motor deviation control simulation model is built to verify the feasibility of the left and right wheel synchronous control algorithm based on speed deviation; by adding a left and right wheel speed coupling term to the DC motor model, and through the PI controller, the left and right wheel synchronous control is realized; a four-wheel independent drive electric vehicle straight line control simulation model is built in Simulink to verify the feasibility of the front and rear wheel group synchronous control algorithm based on speed deviation. The step S100 of the above scheme is the left and right wheel speed difference control, by taking the speed difference of the left and right wheels as a reference variable, the control signal of the motor can be adjusted in real time, so that the rotation speed of the left and right drive wheels is as close as possible; it helps to reduce the side slip and deviation of the vehicle when driving straight, and improves the stability of driving; the PI controller can quickly respond to the change of the speed difference and output the adjustment signal in time to ensure that the vehicle can quickly adapt to the road conditions and maintain straight driving. The significance achieved is: by reducing the speed difference, the vehicle is more stable when driving straight, and the comfort of passengers is improved; the stable driving state reduces the mechanical wear of the vehicle and prolongs the service life of the vehicle. The step S200 of the front and rear wheel group speed difference control, by controlling the speed difference between the front and rear wheel groups, the differential speed between the front and rear wheel groups can be effectively suppressed to ensure the overall coordination of the vehicle when driving straight; the independent PI controller of each drive wheel can realize the coordination of four-wheel speed to ensure that each wheel can operate according to the predetermined speed and improve the overall control accuracy. The significance achieved is: the synchronous control of the front and rear wheel groups makes the vehicle more easy to control when driving straight, and the driver can control the vehicle more easily; by reducing the speed difference between the front and rear wheel groups, the vehicle responds more quickly in emergency situations, improving the safety of driving. The step S300 of the simulation model verification, by building a left and right wheel DC motor deviation control simulation model, the feasibility of the left and right wheel synchronous control algorithm based on speed deviation can be verified to ensure the effectiveness of the algorithm in actual application; a four-wheel independent drive electric vehicle straight line control simulation model is built in Simulink to further optimize the front and rear wheel group synchronous control algorithm and improve the precision and reliability of the control strategy. The significance achieved is: through simulation model verification, problems can be found and solved before actual application, reducing the trial and error cost in the research and development process; the verification result of the simulation model can be directly applied to actual product development, accelerating the application of new technology and the time to market of products.

[0071] In summary, through fine step design and simulation verification, the stability and efficiency of the four-wheel independent drive electric vehicle during straight driving are ensured, the driving experience and safety are improved, the research and development cost is reduced, and the application of new technology is accelerated.

[0072] Embodiment 2: as Figure 2 shown, on the basis of embodiment 1, the process of calculating the difference value signal and outputting the control signal by the PI controller provided by the embodiment of the application comprises the following steps:

[0073] S101: real-time detection of the rotation speed of the left and right wheels, calculation of the speed difference of the left and right wheels; the speed difference is taken as the input signal of the PI controller; the proportional gain is multiplied by the speed difference to obtain the output of the proportional part; the integral gain is multiplied by the integral of the speed difference to obtain the output of the integral part;

[0074] The proportional part immediately produces a control output according to the current speed difference, reducing the speed difference; the integral part eliminates the steady-state error caused by the accumulation of system errors;

[0075] The high-level control strategy of the PI controller is:

[0076]

[0077] In the formula, u(t) represents the output signal of the controller, which acts on the motor controller to adjust the output torque or speed of the motor, e(t) represents the speed difference at the current moment, that is, the difference between the target speed and the actual speed, K p (t) represents the adaptive proportional gain, which is dynamically adjusted according to the real-time state of the system to optimize the control effect, K i (t) represents the adaptive integral gain, which is dynamically adjusted according to the real-time state of the system to eliminate steady-state error, represents the integral of the speed difference, represents the cumulative amount of the speed difference from the initial moment to the current moment, and alpha represents the differential gain coefficient, which is used to adjust the weight of the differential part to improve the response speed of the system, represents the differential of the speed difference, represents the rate of change of the speed difference, and beta represents the second-order differential gain coefficient, which is used to adjust the weight of the second-order differential part to further improve the stability of the system, represents the second-order differential of the speed difference, represents the acceleration of the rate of change of the speed difference, and gamma represents the third-order differential gain coefficient, which is used to adjust the weight of the third-order differential part to further improve the robustness of the system, The third-order differential of the speed difference value, the rate of change of the acceleration of the speed difference value; by introducing adaptive control and fuzzy control and other advanced control strategies, combined with the differential, second-order differential and third-order differential part, the accuracy, stability and robustness of the PI controller can be significantly improved, so that it can better adapt to the complex and variable system environment;

[0078] S102: Add the outputs of the proportional part and the integral part to obtain the total output signal of the PI controller, and the total output signal acts as a control signal on the motor controllers of the left and right wheels; the motor controllers of the left and right wheels adjust the output torque or speed of the motor according to the received control signal to reduce the speed difference; through continuous adjustment, the speeds of the left and right wheels tend to be consistent to the greatest extent;

[0079] S103: The speed difference value is continuously detected and fed back to the PI controller, and the PI controller continuously adjusts the control output according to the feedback signal.

[0080] The working principle and beneficial effects of the above technical solution are as follows: This embodiment first detects the rotational speed of the left and right wheels in real time and calculates the speed difference between the two wheels; the speed difference is used as the input signal of the PI controller; the proportional gain is multiplied by the speed difference to obtain the proportional part output; the integral gain is multiplied by the integral of the speed difference to obtain the integral part output; the proportional part generates a control output immediately based on the current speed difference to reduce the speed difference; the integral part eliminates the steady-state error caused by the accumulation of system errors; secondly, the outputs of the proportional and integral parts are added to obtain the total output signal of the PI controller, which is used as a control signal and applied to the motor controllers of the left and right wheels respectively; the motor controllers of the left and right wheels adjust the output torque or speed of the motor according to the received control signal to reduce the speed difference; through continuous adjustment, the rotational speeds of the left and right wheels tend to be consistent, achieving the greatest approximation; finally, the speed difference is continuously detected and fed back to the PI controller, and the PI controller continuously adjusts the control output according to the feedback signal. Step S101 of the above scheme involves speed difference detection and PI controller input to ensure that the acquired speed data is up-to-date and can promptly reflect the current driving state; quantifying the speed difference between the left and right wheels provides a clear reference for control; and using the speed difference as the controller input to initiate the closed-loop control process. The significance of this step is: ensuring that the control system can respond promptly to speed changes, improving control sensitivity and response speed; clarifying the speed difference between the left and right wheels through speed difference calculation, providing a basis for precise control; and laying the foundation for proportional and integral control, ensuring the continuity and stability of the control process. Step S102 involves PI controller output and motor control, immediately generating a control output based on the current speed difference to quickly reduce the speed difference; eliminating steady-state errors caused by the accumulation of system errors, ensuring long-term control stability; adding the outputs of the proportional and integral parts to obtain a comprehensive control signal, which is applied to the motor controllers of the left and right wheels; and adjusting the motor output torque or speed based on the received control signal to reduce the speed difference. The significance achieved is as follows: The proportional component ensures the control system can respond quickly to speed changes, reducing transient errors; the integral component eliminates long-term accumulated errors, ensuring high-precision control of the system in steady state; through the combined effect of proportional and integral components, precise control of the speed difference is achieved, ensuring the maximum approximation of the rotational speeds of the left and right wheels; the motor controller adjusts its output according to the control signal, ensuring that the rotational speeds of the left and right wheels gradually become consistent, providing a basis for linear motion. Step S103 involves feedback and closed-loop control: the speed difference is continuously detected and fed back to the PI controller, ensuring the continuity and real-time nature of the control process; the PI controller continuously adjusts its control output according to the feedback signal, ensuring that the rotational speeds of the left and right wheels always remain as close as possible.The significance of this is to ensure the closed-loop nature and stability of the control process through continuous feedback and adjustment, preventing the system from deviating from the target state; to dynamically adjust the control output based on real-time feedback signals, ensuring that the system maintains good control performance under various driving conditions; and to ensure the system remains stable during long-term operation through continuous feedback and adjustment, avoiding control failure due to error accumulation.

[0081] In summary, this embodiment achieves the greatest possible approximation of the rotational speeds of the left and right drive wheels, laying the foundation for synchronous control of linear motion. Specifically, it ensures real-time detection and quantification of speed differences, achieves precise control of speed differences through proportional and integral control, and ensures the long-term stability and dynamic adjustment capability of the system through feedback and closed-loop control. These three steps work together to enable the four-wheel independent drive electric vehicle to maintain the stability of linear motion under various driving conditions.

[0082] Example 3: As Figure 3 As shown, based on Embodiment 2, the process of adjusting the output torque or speed of the motor provided in this embodiment of the invention includes the following steps:

[0083] S1021: After receiving the control signal from the PI controller, the motor controller analyzes the signal strength; based on the analyzed signal strength, the motor controller sets a reference torque or speed, which is calculated based on the difference between the current motor operating state and the target speed.

[0084] S1022: If the signal strength indication requires torque adjustment, the motor controller adjusts the electromagnetic torque of the motor by changing the motor current or voltage; if the signal strength indication requires speed adjustment, the motor controller adjusts the motor speed by changing the motor power supply frequency or voltage.

[0085] Specifically, increasing the current or voltage increases the electromagnetic torque, thereby increasing the motor's output torque; conversely, decreasing the current or voltage decreases the electromagnetic torque, thereby decreasing the motor's output torque. Increasing the power supply frequency or voltage increases the motor's speed; conversely, decreasing the power supply frequency or voltage decreases the motor's speed.

[0086] S1023: The motor controller continuously monitors the actual output torque or speed of the motor and compares it with the set reference value. If there is a deviation, the motor controller fine-tunes the current, voltage or frequency according to the magnitude and direction of the deviation. When the output torque or speed of the motor reaches the expected value, the motor controller enters the steady-state holding mode and continuously monitors and fine-tunes the operating status of the motor.

[0087] The working principle and beneficial effects of the above technical solution are: firstly, after the motor controller receives the control signal transmitted by the PI controller, the strength of the signal is analyzed; according to the analyzed signal strength, the motor controller sets a reference torque or speed, and the reference torque or speed is calculated according to the current motor operating state and the target speed difference; secondly, if the signal strength indicates that the torque needs to be adjusted, the motor controller adjusts the electromagnetic torque of the motor by changing the current or voltage of the motor; if the signal strength indicates that the speed needs to be adjusted, the motor controller adjusts the speed of the motor by changing the power supply frequency or voltage of the motor; specifically, increasing the current or voltage will increase the electromagnetic torque, thereby increasing the output torque of the motor; on the contrary, reducing the current or voltage will reduce the electromagnetic torque, thereby reducing the output torque of the motor; increasing the power supply frequency or voltage will increase the speed of the motor; on the contrary, reducing the power supply frequency or voltage will reduce the speed of the motor; finally, the motor controller continuously monitors the actual output torque or speed of the motor and compares it with the set reference value; if there is a deviation, the motor controller adjusts the current, voltage or frequency according to the size and direction of the deviation; when the output torque or speed of the motor reaches the expected value, the motor controller enters a steady state maintenance mode, continuously monitors and fine-tunes the operating state of the motor. The step S1021 of the above scheme analyzes the signal strength and sets the reference torque or speed, accurately analyzes the strength of the control signal transmitted by the PI controller, and ensures the accuracy of the control instruction; according to the analyzed signal strength and the current motor operating state, a reasonable reference torque or speed is set to provide a reference for adjustment. Significance: By accurately analyzing the signal strength and setting the reference value, the motor controller can accurately adjust according to the actual demand, avoiding excessive or insufficient adjustment; the set reference value provides a basis for stable operation of the motor, ensuring that the motor can maintain stable output in various operating states. Step S1022 adjusts the electromagnetic torque or speed of the motor, adjusts the electromagnetic torque of the motor by changing the current or voltage of the motor, and realizes accurate control of the output torque of the motor; by changing the power supply frequency or voltage of the motor, the speed of the motor is adjusted to realize accurate control of the output speed of the motor. Significance: According to the signal strength indication, the output torque or speed of the motor is flexibly adjusted to meet the needs of different working conditions; by accurately adjusting the current, voltage or frequency, the motor can reach the expected output in the shortest time, improving the response speed and efficiency of the system. Step S1023 monitors and adjusts, continuously monitors the actual output torque or speed of the motor to ensure that the controller can discover deviations in time; according to the monitored deviation, dynamically adjust the current, voltage or frequency to ensure that the output torque or speed of the motor always remains near the expected value. Significance: Through real-time monitoring and dynamic adjustment, closed-loop control is realized to ensure that the motor can maintain stable output under various external condition changes; it can adaptively adjust according to the actual operating state to improve the robustness and reliability of the system.

[0088] In summary, the motor controller of the embodiment can accurately adjust the output torque or speed of the motor according to the strength of the signal, ensuring that the motor can operate stably and efficiently under various working conditions. Not only does it improve the control accuracy and response speed of the system, but also enhances the adaptability and robustness of the system, thereby playing a greater role in practical applications.

[0089] Embodiment 4: As shown in Embodiment 3, on the basis of Embodiment 3, the process of adjusting torque and speed provided by the embodiment of the application comprises the following steps: Figure 4

[0090] S10221: Calculate the difference between the target torque and the actual torque, multiply the difference between the target torque and the actual torque by the proportional gain, and add the integral of the difference multiplied by the integral gain to obtain the torque signal strength;

[0091] S10222: Calculate the difference between the target speed and the actual speed, and determine the proportional gain and the integral gain; multiply the difference between the target speed and the actual speed by the proportional gain, and add the integral of the difference multiplied by the integral gain to obtain the speed signal strength;

[0092] S10223: Compare the torque signal strength and the speed signal strength; if the torque signal strength is greater than the speed signal strength, and torque control is the current primary task, then adjust the torque; otherwise, if the speed signal strength is greater than the torque signal strength, and speed control is the current primary task, then adjust the speed;

[0093] Wherein, the expression for calculating the torque signal strength is:

[0094] Torque strength signal = K p ·(T target -T actual )+K i ·∫(T target -T actual )dt

[0095] In the formula, T target represents the target torque, T actual represents the actual torque; K p represents the proportional coefficient; K i represents the integral coefficient;

[0096] The expression for calculating the speed signal strength is:

[0097] Speed signal strength = K p ·(ω target -ω actual )+K i ·∫(ω target -ω actual )dt ​

[0098] ω target ω actual ω

[0099] The working principle and beneficial effects of the above technical solution are as follows: first, the difference between the target torque and the actual torque is calculated, the difference between the target torque and the actual torque is multiplied by the proportional gain, and the integral of the difference is multiplied by the integral gain to obtain the torque signal strength; second, the difference between the target speed and the actual speed is calculated, and the proportional gain and the integral gain are determined; the difference between the target speed and the actual speed is multiplied by the proportional gain, and the integral of the difference is multiplied by the integral gain to obtain the speed signal strength; finally, the torque signal strength and the speed signal strength are compared; if the torque signal strength is greater than the speed signal strength, and torque control is the current primary task, then the torque is adjusted; otherwise, if the speed signal strength is greater than the torque signal strength, and speed control is the current primary task, then the speed is adjusted. The step S10221 of calculating the torque signal strength quantifies the torque difference into the torque signal strength by calculating the difference between the target torque and the actual torque, and combining the proportional gain and the integral gain; the introduction of the proportional gain and the integral gain enables the system to dynamically adjust according to the size and duration of the torque difference, ensuring the accuracy and stability of the torque control. Significance: By quantifying the torque difference, the system can more accurately control the torque output, ensuring the stable operation of the mechanical system; the dynamic adjustment mechanism enables the system to quickly respond to torque changes, improving the response speed and efficiency of the control system. The step S10222 of calculating the speed signal strength quantifies the speed difference into the speed signal strength by calculating the difference between the target speed and the actual speed, and combining the proportional gain and the integral gain; the introduction of the proportional gain and the integral gain enables the system to dynamically adjust according to the size and duration of the speed difference, ensuring the accuracy and stability of the speed control. Significance: By quantifying the speed difference, the system can more accurately control the speed output, ensuring the stable operation of the mechanical system; the dynamic adjustment mechanism enables the system to quickly respond to speed changes, improving the response speed and efficiency of the control system. The step S10223 of comparing the torque signal strength and the speed signal strength enables the system to determine whether the primary task of the current control is torque control or speed control by comparing the torque signal strength and the speed signal strength; according to the comparison result of the signal strength, the control strategy can be flexibly adjusted to ensure the best control effect under different working conditions. Significance: By priority judgment, the optimal selection between torque and speed control can be made to ensure the best control effect under different working conditions; flexible adjustment of the control strategy enables the system to maintain stable operation when facing complex working conditions, improving the reliability and stability of the overall system.

[0100] In summary, the embodiment can accurately, dynamically and flexibly adjust between torque and speed control, ensuring that the mechanical system can achieve the best control effect under various working conditions. Not only improves the response speed and control accuracy of the system, but also enhances the stability and reliability of the system, thereby improving the performance and efficiency of the overall mechanical system.

[0101] Embodiment 5: as shown in the embodiment 1, on the basis of the embodiment, the process of realizing the cooperation of four-wheel speed through the independent PI control of each drive wheel provided by the embodiment of the application comprises the following steps: Figure 5

[0102] S201: through the sensor installed on each wheel, the real-time speed data of the front and rear wheels is obtained; the speed difference between the front and rear wheel groups is calculated, and the difference is a control variable, reflecting the speed inconsistency that may occur in the driving process of the front and rear wheel groups;

[0103] S202: based on the calculated speed difference, a corresponding control signal is generated through multiple PI controllers; the PI controller adjusts the motor output of each drive wheel according to the size and change trend of the speed difference, and suppresses the speed difference between the front and rear wheel groups;

[0104] S203: the motor of each drive wheel receives the control signal from the PI controller and adjusts its speed according to the control signal, and the speed of the front and rear wheel groups is effectively cooperatively controlled; the speed of the front and rear wheel groups is continuously monitored, and the parameters of the PI controller are dynamically adjusted as needed.

[0105] ​The working principle and beneficial effects of the above technical solution are: firstly, the real-time speed data of the front and rear wheels is obtained through the sensors installed on each wheel; the speed difference between the front and rear wheel groups is calculated, and the difference is the control variable, reflecting the possible speed inconsistency of the front and rear wheel groups during driving; secondly, based on the calculated speed difference, a corresponding control signal is generated through multiple PI controllers; the PI controller adjusts the motor output of each drive wheel according to the size and change trend of the speed difference, and suppresses the speed difference between the front and rear wheel groups; finally, the motor of each drive wheel receives the control signal from the PI controller and adjusts its speed according to the control signal, and the speed of the front and rear wheel groups is effectively coordinated; the speed of the front and rear wheel groups is continuously monitored and the parameters of the PI controller are dynamically adjusted as needed. The step S201 of the above scheme is real-time data acquisition and difference calculation, the speed data of the front and rear wheels is obtained in real time through the sensor, and the speed difference is calculated; it ensures that the control system can timely perceive the speed difference of the front and rear wheel groups, and provides accurate data basis for the later control; the real-time and accuracy are high, which can quickly respond to the speed change in the driving process and avoid control failure caused by data lag. The application of PI controller in step S202 generates a control signal through multiple PI controllers, and adjusts the motor output of each drive wheel according to the size and change trend of the speed difference; it can accurately control the speed of each wheel and suppress the speed difference between the front and rear wheel groups; the PI controller has good dynamic response and stability, which can effectively eliminate the speed difference and ensure the coordinated consistency of the four-wheel speed. In step S203, the motor speed is adjusted and continuously monitored, and the motor of each drive wheel adjusts the speed according to the signal of the PI controller to realize the coordinated control of the speed of the front and rear wheel groups; the speed of the front and rear wheel groups is continuously monitored and the parameters of the PI controller are dynamically adjusted to ensure the continuous optimization of the control effect; dynamically adjusting the parameters can adapt to different road conditions and driving conditions, ensuring that the control system can maintain high efficiency and stability in various situations.

[0106] In summary, this embodiment, through an independent PI controller, can precisely control the speed of each drive wheel, ensuring the consistency of speed across all four wheels and avoiding energy waste and performance degradation caused by inconsistent speeds. It can dynamically adjust control parameters based on real-time data to adapt to different road conditions and driving conditions, improving the system's robustness and adaptability. This embodiment, through coordinated control, reduces the impact of motor braking on the battery, improves energy utilization, and extends the electric vehicle's driving range. It ensures the electric vehicle maintains maximum driving capability during straight-line driving, enhancing the overall vehicle performance and driving experience. Traditional four-wheel drive systems typically rely on mechanical differentials to adjust wheel speeds, which can easily lead to inefficiency and mechanical wear under complex road conditions. This embodiment, through electronic control and a PI controller, achieves independent and precise control of each wheel, avoiding the inherent defects of mechanical differentials and improving the system's flexibility and reliability. The significance achieved includes: ensuring smooth vehicle operation under various road conditions through precise speed control, improving driving safety and comfort; reducing energy waste and extending the electric vehicle's driving range through optimized energy utilization, aligning with the trend of energy conservation and environmental protection; and representing the forefront of electric vehicle control technology, promoting the progress and innovation of electric vehicle technology.

[0107] In summary, this embodiment significantly improves the performance and energy efficiency of electric vehicles through precise control and dynamic adaptability, and has important practical application value and far-reaching technical significance.

[0108] Example 6: As Figure 6 As shown, based on Embodiment 5, the process of adjusting the motor output of each drive wheel provided in this embodiment of the invention includes the following steps:

[0109] S2021: Real-time monitoring of the speed of the front and rear wheel sets, and calculation of the speed difference;

[0110] S2022: Multiply the calculated speed difference by the proportional gain to obtain the proportional control signal. The proportional gain is adjusted according to the dynamic characteristics of the system and the desired response speed.

[0111] S2023: The generated proportional control signal acts on the motor to adjust the motor's output torque in order to reduce the speed difference; the proportional control signal will be converted into a corresponding voltage or current signal by the motor controller to drive the motor to adjust its output torque.

[0112] The working principle and beneficial effects of the above technical solution are: firstly, the speed difference is calculated by real-time monitoring the speed of the front and rear wheel groups; secondly, the calculated speed difference is multiplied by the proportional gain to obtain the proportional control signal, and the proportional gain is adjusted according to the dynamic characteristics of the system and the expected response speed; finally, the generated proportional control signal acts on the motor to adjust the output torque of the motor to reduce the speed difference; the proportional control signal is converted into a corresponding voltage or current signal by the motor controller to drive the motor to adjust its output torque. The step S2021 of the above scheme monitors the speed of the front and rear wheel groups in real time, calculates the speed difference, and can quickly capture the change of the speed difference by monitoring the speed of the front and rear wheel groups in real time, providing timely data support for control decision; the calculation of the speed difference provides accurate input for subsequent proportional control, ensuring the accuracy of the control signal. The significance achieved is: real-time monitoring and calculation of the speed difference enables the system to respond at the first time when the speed difference appears, improving the response speed of the system; the proportional gain application provides a reliable data basis, ensuring that the generation and action of the control signal are targeted. The proportional gain is adjusted according to the dynamic characteristics of the system and the expected response speed in step S2022; the adjustment of the proportional gain enables the system to adaptively generate appropriate control signals according to different dynamic characteristics and response requirements; the selection of the proportional gain can be dynamically adjusted according to the actual operation of the system, ensuring that the system can maintain good performance under different working conditions. The significance achieved is: through the adjustment of the proportional gain, the system can optimize the generation of the control signal to make it more consistent with the dynamic characteristics and response requirements of the system, improving the precision and efficiency of the control; reasonable selection of the proportional gain can avoid oscillation or overshoot of the system, ensuring the stability of the system. The proportional control signal generated in step S2023 acts on the motor to adjust the output torque of the motor to reduce the speed difference; the proportional control signal is converted into a corresponding voltage or current signal by the motor controller to drive the motor to adjust its output torque; the proportional control signal directly acts on the motor to quickly reduce the speed difference by adjusting the output torque of the motor, realizing direct control of the system; the motor controller converts the proportional control signal into a corresponding voltage or current signal to drive the motor to respond quickly and adjust its output torque. The significance achieved is: through the direct action of the proportional control signal, the output torque of the motor can be quickly adjusted to quickly reduce the speed difference and improve the response speed of the system; the motor controller converts the proportional control signal into a corresponding voltage or current signal to ensure the accuracy of the torque adjustment of the motor output and improve the precision and stability of the control.

[0113] In summary, the embodiment can realize accurate adjustment of the output of each drive wheel motor, and the specific technical effects include real-time, accuracy, adaptability, flexibility, direct control and fast response. The achieved significance includes improving the response speed of the system, optimizing the generation of control signals, ensuring the stability of the system and accurately controlling the output torque of the motor. Through these steps, the system can maintain good performance under different working conditions and meet various dynamic characteristics and response requirements.

[0114] Embodiment 7: As shown in Embodiment 6, on the basis of Embodiment 6, the process for obtaining the proportional control signal provided by the embodiment of the application comprises the following steps: Figure 7

[0115] S20221: Set a reference model, which is an ideal linear system. The controller of the motor is composed of a feedforward controller and a feedback controller; the feedforward controller is used to compensate for dynamic characteristics, and the feedback controller is used to reduce errors;

[0116] S20222: Use Lyapunov stability theory to design an adaptive law to obtain the rate of change of the parameters of the feedforward controller and the feedback controller;

[0117] S20223: The closed-loop transfer function considers the effects of the feedforward controller and the feedback controller, and shows the relationship between the output and the input; by adjusting the controller parameters, the dynamic response is optimized.

[0118] The reference model of the embodiment is an ideal linear system, and the transfer function can be expressed as:

[0119]

[0120] Where: G m (s) is the transfer function of the reference model, Y m (s) is the output of the reference model, and U m (s) is the input of the reference model.

[0121] The output of the controller is expressed as:

[0122] u(t)=θ1(t)·r(t)+θ2(t)·y(t)

[0123] Where: u(t) is the output of the controller, θ1 is the parameter of the feedforward controller, r(t) is the reference input, θ2(t) is the parameter of the feedback controller, and y(t) is the output of the system.

[0124] The adaptive law is expressed as:

[0125]

[0126] Where: ​It is the rate of change of the feedforward controller parameters. γ is the rate of change of the feedback controller parameters, γ1 and γ2 are adaptive gains used to adjust the update rate of the parameters, and e(t) is the system error, defined as e(t) = y m (t)-y(t), where y m (t) is the output of the reference model;

[0127] The closed-loop transfer function is expressed as:

[0128]

[0129] Among them: G c (s) is the closed-loop transfer function of the system, G p Y(s) is the open-loop transfer function of the system, Y(s) is the output of the system, and R(s) is the input of the system. By introducing model reference adaptive control, not only are the dynamic characteristics of the system considered, but the parameters of the controller are also adjusted online through the adaptive law, so that the output of the system is as close as possible to the output of the reference model. It is very effective in practical applications and can cope with changes in system parameters and external disturbances.

[0130] The working principle and beneficial effects of the above technical solution are: firstly, the reference model is set, the reference model is an ideal linear system, the controller of the motor is composed of a feedforward controller and a feedback controller; the feedforward controller is used to compensate the dynamic characteristics, and the feedback controller is used to reduce the error; secondly, the Lyapunov stability theory is used to design the adaptive law, and the variation rate of the parameters of the feedforward controller and the feedback controller is obtained; finally, the closed-loop transfer function considers the effects of the feedforward controller and the feedback controller, and the relationship between the output and the input is displayed; by adjusting the controller parameters, the dynamic response is optimized. The step S20221 of the above scheme sets the reference model, sets an ideal linear system as the reference model, which can provide a clear target and standard for the actual system; the feedforward controller is used to compensate the dynamic characteristics of the system, and by pre-setting the control signal, the response time of the system can be reduced, and the rapidity and stability of the system can be improved; the feedback controller is used to reduce the error of the system, and by adjusting the control signal in real time, the output of the system can be as close as possible to the reference input, and the accuracy and stability of the system can be improved. The significance achieved is: by setting the reference model, a clear target is provided for control, making the control process more targeted and effective; the combination of the feedforward controller and the feedback controller can significantly improve the dynamic response and stability of the system, making the system more reliable and efficient in actual application. The step S20222 uses the Lyapunov stability theory to design the adaptive law, and through the Lyapunov stability theory, the stability of the system can be ensured, and the system can be prevented from being unstable or oscillating during the control process; the adaptive law can adjust the controller parameters according to the real-time state of the system, so that the system can adapt to different working environments and conditions, and the robustness and adaptability of the system can be improved. The significance achieved is: through the Lyapunov stability theory, the system is always stable during the control process, avoiding system failure or performance degradation due to instability; the design of the adaptive law enables the system to maintain good performance under different working conditions, enhancing the robustness and adaptability of the system. The step S20223 considers the effects of the feedforward controller and the feedback controller in the closed-loop transfer function, which comprehensively considers the effects of the feedforward controller and the feedback controller, and fully describes the dynamic characteristics of the system, providing a theoretical basis for optimization; by adjusting the controller parameters, the dynamic response of the system can be optimized, making it more stable, fast and accurate. The significance achieved is: the design of the closed-loop transfer function enables the system to comprehensively optimize its dynamic response, making it more efficient and reliable in actual application; by adjusting the controller parameters, the performance of the system can be significantly improved, enabling it to maintain good performance under various working conditions.

[0131] In summary, the embodiment can not only set clear goals and standards, but also ensure stability and robustness in the control process. The design of the closed-loop transfer function enables the system to optimize its dynamic response comprehensively, making it more efficient and reliable in practical applications. It enables the system to maintain good performance in complex working environments and meet various application requirements.

[0132] Embodiment 8: As shown in the embodiment 1, on the basis of the embodiment 1, the process of building a four-wheel independent drive electric vehicle straight line control simulation model in Simulink provided by the embodiment of the application comprises the following steps: Figure 8

[0133] S301: Open Simulink and create a new model file, find and add 4 DC motor modules in the Simulink library browser, which represent the four drive wheels of the electric vehicle; configure the corresponding parameters for each motor module;

[0134] S302: Add a PI controller for each motor module to control the speed of the motor; the PI controller will adjust the output of the motor according to the speed difference signal; calculate the speed difference between the front and rear wheel groups and input it into the corresponding PI controller as a control signal to suppress the differential speed between the front and rear wheel groups; add a drive and set value module to set the target speed of each motor; provide the corresponding speed set value for each motor according to the straight line motion requirements of the vehicle;

[0135] S303: Connect the speed output of each motor to the corresponding PI controller, connect the output of the PI controller to the input of the motor, and connect the output of the front and rear signal processing modules to the corresponding PI controller; connect the output of the drive and set value module to the speed setting end of each motor; set the simulation time, step size and other parameters, run the simulation model, and observe the speed synchronization of the four-wheel independent drive electric vehicle in straight line motion.

[0136] ​The working principle and beneficial effects of the technical solution are: the embodiment first opens Simulink and creates a new model file, finds and adds four DC motor modules in the Simulink library browser, which represent the four drive wheels of the electric vehicle; configure the corresponding parameters for each motor module; secondly, add a PI controller to each motor module for controlling the speed of the motor; the PI controller will adjust the output of the motor according to the speed difference signal; calculate the speed difference between the front and rear wheel groups and input it as a control signal into the corresponding PI controller to suppress the differential speed between the front and rear wheel groups; add a drive and set value module to set the target speed of each motor; provide the corresponding speed set value for each motor according to the straight line motion requirement of the vehicle; finally, connect the speed output of each motor to the corresponding PI controller, connect the output of the PI controller to the input end of the motor, and connect the output of the front and rear signal processing modules to the corresponding PI controller; connect the output of the drive and set value module to the speed setting end of each motor; set the simulation time, step size and other parameters, run the simulation model, and observe the speed synchronization of the four-wheel independent drive electric vehicle in straight line motion. The step S301 model initialization and motor configuration of the above scheme creates a new Simulink model file to provide a basic environment for module addition and connection; adds four DC motor modules, which represent the four drive wheels of the electric vehicle, to provide a physical basis for simulation; configures the corresponding parameters (such as resistance, inductance, torque constant, etc.) for each motor module to ensure that the simulation results are consistent with the actual motor characteristics, improve accuracy and reliability. The significance achieved is: providing a basis for building a simulation model to ensure that the steps can be smoothly performed; by configuring motor parameters, the physical characteristics of the actual motor are simulated to make the simulation results closer to the real situation. The step S302 controller and signal processing module addition adds a PI controller to each motor module to control the speed of the motor, ensures that the motor can adjust the output according to the speed difference signal, and realizes the cooperation of the four-wheel speed; calculates the speed difference between the front and rear wheel groups and inputs it as a control signal into the corresponding PI controller to suppress the differential speed between the front and rear wheel groups, ensuring the stability of the vehicle's straight line motion; adds a drive and set value module to set the target speed of each motor, provides the corresponding speed set value for each motor according to the straight line motion requirement of the vehicle, and ensures that the simulation model can simulate the actual driving demand. The significance achieved is: through the PI controller, the control accuracy of the motor is improved to ensure that the four-wheel speed can cooperate to the greatest extent; by calculating and suppressing the speed difference between the front and rear wheel groups, the straight line motion stability of the vehicle is enhanced, and the deviation caused by the speed difference is reduced; by setting the target speed, the actual driving demand is simulated to make the simulation results more practical and valuable.Step S303 module connection and simulation running, connecting the speed output of each motor to the corresponding PI controller, connecting the output of the PI controller to the input end of the motor, ensuring that the control signal can be correctly transmitted; connecting the output of the front and rear signal processing modules to the corresponding PI controller, ensuring that the speed difference between the front and rear wheel groups can be correctly processed and suppressed; connecting the output of the drive and setting value module to the speed setting end of each motor, ensuring that each motor can receive the correct target speed; setting the simulation time, step size and other parameters, ensuring that the simulation can be completed within a reasonable time and the results have sufficient accuracy; running the simulation model, observing the speed synchronization of the four-wheel independent drive electric vehicle in straight line motion, and verifying the effectiveness of the control algorithm. The significance achieved: through module connection, each part is integrated into a complete simulation system, ensuring that each module can work cooperatively; through simulation running, the effectiveness of the control algorithm is verified, ensuring that the four-wheel speed can be coordinated to the greatest extent to achieve the expected control effect; through observation of the simulation results, the synchronization of the four-wheel speed is analyzed, providing a basis for further optimization of the control parameters, ensuring that the simulation results can meet the actual application requirements.

[0137] In summary, the embodiment successfully builds a four-wheel independent drive electric vehicle straight line control simulation model in Simulink and verifies the feasibility of the speed deviation-based synchronization control algorithm. Each step provides necessary technical support and guarantee for the final simulation results, ensuring that the simulation model can accurately simulate the straight line motion control process of the actual vehicle.

[0138] Embodiment 9: as shown in Figure 9 On the basis of embodiment 8, the visualization process of running the simulation model provided by the embodiment of the application comprises the following steps:

[0139] S3031: connecting the speed output signal of each motor to the corresponding oscilloscope module, and connecting the speed output signals of all motors to a multi-input oscilloscope module;

[0140] S3032: configuring the parameters of the oscilloscope module, setting the time range and display mode, etc.

[0141] S3033: running the simulation and observing the results, displaying the speed curve of each motor in real time, checking whether the speeds of the motors are synchronized and whether there is a significant speed difference.

[0142] The working principle and beneficial effects of the above technical solution are: first, the speed output signal of each motor is connected to the corresponding oscilloscope module, and the speed output signals of all motors are connected to a multi-input oscilloscope module; second, the parameters of the oscilloscope module are configured, and the time range and display mode are set; finally, the simulation is run and the results are observed, and the speed curve of each motor is displayed in real time, and the speed of each motor is checked for synchronization and whether there is a significant speed difference. Step S3031 of the above scheme connects the speed output signal of each motor to the corresponding oscilloscope module, and connects the speed output signals of all motors to a multi-input oscilloscope module; by connecting the speed output signal of each motor to a separate oscilloscope module, the speed change of each motor can be clearly seen. At the same time, connecting the speed signals of all motors to a multi-input oscilloscope module facilitates comparison and analysis of the speed relationship between multiple motors; the connection method embodies the idea of modular design, making the input and output of signals clearer and easier to manage. The significance achieved: through the oscilloscope module, users can intuitively observe the speed change of each motor, which helps to quickly find problems; the use of a multi-input oscilloscope module allows users to easily compare the speed curves of different motors to determine whether they are synchronized or have differences. Step S3032 configures the parameters of the oscilloscope module, sets the time range and display mode, etc., by configuring the parameters of the oscilloscope module, users can set the time range, display mode, etc. according to their needs, making the display results more in line with actual needs; reasonable parameter setting can optimize the display effect, making the waveform clearer and easier to observe and analyze. The significance achieved: through reasonable parameter configuration, users can more accurately analyze the speed change of the motor, improving the accuracy of analysis; personalized display settings improve user experience, allowing users to more comfortably observe and analyze. Step S3033 runs the simulation and observes the results, displaying the speed curve of each motor in real time, checking whether the speed of each motor is synchronized and whether there is a significant speed difference; by running the simulation and displaying the speed curve in real time, users can monitor the running state of the motor in real time and detect abnormalities in a timely manner; by observing the speed curve, users can intuitively determine whether the speed of each motor is synchronized and whether there is a significant speed difference. The significance achieved: real-time monitoring and synchronization detection help to quickly diagnose problems in motor operation, such as inconsistent speed or abnormal fluctuations; by observing the simulation results, users can further optimize the design of the motor control system, improving the stability and efficiency of the system.

[0143] In summary, the present embodiment helps users to intuitively and accurately analyze the speed change of the motor through modular design, personalized configuration and real-time monitoring, thereby improving the stability and efficiency of the system.

[0144] Embodiment 10: as Figure 10As shown, on the basis of examples 1-9, the four-wheel independent drive electric vehicle linear motion synchronous control system provided by the embodiment of the application comprises:

[0145] The wheel group internal synchronous control module is responsible for adding the speed difference of the left and right wheels as a reference variable to the closed-loop control of the motor, calculating the difference signal through a PI controller and outputting a control signal, so that the rotation speed of the left and right drive wheels is maximally approximated;

[0146] The wheel group internal synchronous control module is responsible for adding the speed difference of the left and right wheels as a reference variable to the closed-loop control of the motor, calculating the difference signal through a PI controller and outputting a control signal, so that the rotation speed of the left and right drive wheels is maximally approximated;

[0147] The motion simulation verification module is responsible for building a left and right wheel DC motor deviation control simulation model, verifying the feasibility of the left and right wheel synchronous control algorithm based on the speed deviation, adding a left and right wheel speed coupling term to the DC motor model, and realizing the cooperative control of the left and right wheels through a PI controller; a four-wheel independent drive electric vehicle linear control simulation model is built in Simulink, and the feasibility of the front and rear wheel group synchronous control algorithm based on the speed deviation is verified.

[0148] The working principle and beneficial effects of the above technical solution are: the wheel group internal synchronization control module of the embodiment takes the speed difference of the left and right wheels as a reference variable and adds it to the closed-loop control of the motor, calculates the difference signal through the PI controller and outputs the control signal, so that the rotation speed of the left and right drive wheels is maximally approximated; the wheel group inter-synchronization control module controls the speed difference between the front and rear wheel groups as a controlled variable, suppresses the differential speed between the front and rear wheel groups, and realizes the cooperation of the four-wheel speed through the independent PI control of each drive wheel; the motion simulation verification module builds a left and right wheel DC motor deviation control simulation model to verify the feasibility of the left and right wheel synchronization control algorithm based on speed deviation; the left and right wheel speed coupling term is added to the DC motor model, and the cooperation control of the left and right wheels is realized through the PI controller; a four-wheel independent drive electric vehicle straight line control simulation model is built in Simulink to verify the feasibility of the front and rear wheel group synchronization control algorithm based on speed deviation. The wheel group internal synchronization control module takes the speed difference of the left and right wheels as a reference variable, adjusts the control signal of the motor in real time, and makes the rotation speed of the left and right drive wheels as close as possible; it helps to reduce the side slip and deviation of the vehicle when driving straight, and improves the stability of driving; the PI controller can quickly respond to the change of the speed difference and timely output the adjustment signal to ensure that the vehicle can quickly adapt to the road conditions and maintain straight driving. The significance achieved is: by reducing the speed difference, the vehicle is more stable when driving straight, and the comfort of passengers is improved; the stable driving state reduces the mechanical wear of the vehicle and prolongs the service life of the vehicle. The wheel group inter-synchronization control module can effectively suppress the differential speed between the front and rear wheel groups by controlling the speed difference between the front and rear wheel groups, ensuring the overall coordination of the vehicle when driving straight; the independent PI controller of each drive wheel can realize the cooperation of the four-wheel speed, ensuring that each wheel can operate at the predetermined speed and improving the overall control accuracy. The significance achieved is: the synchronization control of the front and rear wheel groups makes the vehicle easier to control when driving straight, and the driver can control the vehicle more easily; by reducing the speed difference between the front and rear wheel groups, the vehicle responds more quickly in emergency situations, improving the safety of driving. The motion simulation verification module can verify the feasibility of the left and right wheel synchronization control algorithm based on speed deviation by building a left and right wheel DC motor deviation control simulation model, ensuring the effectiveness of the algorithm in actual application; a four-wheel independent drive electric vehicle straight line control simulation model is built in Simulink to further optimize the front and rear wheel group synchronization control algorithm and improve the precision and reliability of the control strategy. The significance achieved is: through simulation model verification, problems can be found and solved before actual application, reducing the trial and error cost in the research and development process; the verification result of the simulation model can be directly applied to actual product development, accelerating the application of new technologies and the time to market of products.

[0149] This embodiment aims at the speed of two motor cooperative control algorithm simulation, in the DC motor model on the left and right wheel speed coupling term; the speed of left and right drive wheel motor as a variable into the PI control, such as Figure 11 The left and right cooperative control PI controller simulation model, based on the speed deviation of left and right wheel synchronous control algorithm to build the PI controller; wherein KB1, KB2 is the error weight coefficient, by the two kinds of error signal weighting, realize the speed closed loop control and left and right collaborative control of comprehensive control scheme.

[0150] This embodiment will be built in Simulink control four-wheel independent drive straight line control simulation model, to verify the feasibility of the control system; as Figure 12 The four-wheel independent drive electric vehicle straight line control model; it includes four speed control DC motor module, front and rear signal processing module, drive and set value module. Among them, the drive motor 1 is the left front wheel motor, the drive motor 2 is the right front wheel motor, the drive motor 3 is the left rear wheel motor, and the drive motor 4 is the right rear wheel motor.

[0151] The four-wheel cooperative control left and right wheel output torque simulation results, the most important thing for four-wheel straight line motion control is to control the speed of left and right motor to keep consistent. In the simulation process, the drive motor 2 increases the driving torque at 2s; the speed of motor 1 decreases rapidly with the motor 2, and the speed deviation of the two motors changes within the error allowable range and remains equal in a short time.

[0152] In the simulation process, the left rear wheel motor in the rear wheel group drive motor applies a load at 2s; the speed of the left rear wheel decreases immediately after the load is added, and the speed of the left front motor in the front wheel group changes, and the speed of the front and rear wheel groups returns to the same level in a short time. It proves the effectiveness and feasibility of the control algorithm between the front and rear wheel groups.

[0153] The speed changes of the four drive motors are compared. The four drive wheels add the initial load torque at t=0, and the speed remains the same to reach the set value within a certain time. The left front wheel motor runs without adding extra load torque, and the speed V1 is used as the control group. The right front wheel drive motor adds a 0.05N*M torque at 2s, and the left rear wheel drive motor adds a 0.03N*M torque at 2s. Through the speed change of the four wheels, it is proved that the speed of the front and rear drive groups has a strong following degree in the running process, which verifies the feasibility of the four-wheel straight line control. The speed between the front and rear drive groups also has strong following property in the running process, which verifies the effectiveness of the four-wheel control algorithm for the speed between the cooperative groups; by comparing the speed changes of the four drive wheels, when the load torque of one drive wheel increases, the speed of the other drive wheels will also change accordingly, which verifies the effectiveness of the four-wheel coupling control.

[0154] In summary, the embodiment ensures the stability and efficiency of the vehicle in straight-line driving through the modular design of the four-wheel independent drive electric vehicle linear motion synchronous control system. Each module plays a key role, improving the driving experience and safety, while reducing the research and development cost and accelerating the application of new technology. Not only improves the performance of the vehicle, but also lays a solid foundation for future technology development.

[0155] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the equivalent technology of the present application, the present application also intends to include these modifications and variations.

Claims

1. A linear motion synchronization control method for a four-wheel independent drive electric vehicle, characterized by, The method comprises the following steps: The speed difference between the left and right wheels of the electric vehicle is added as a reference variable to the closed-loop control of the motor, and a PI controller is used to calculate the difference signal and output a control signal, so that the rotational speeds of the left and right drive wheels are maximally approximated; The speed difference between the front and rear wheel groups of the electric vehicle is controlled as a controlled variable to suppress the differential speed between the front and rear wheel groups, and the four-wheel speed is coordinated through independent PI control of each drive wheel; A left-right wheel DC motor deviation control simulation model is built to verify the feasibility of the left-right wheel synchronous control algorithm based on speed deviation; a left-right wheel speed coupling term is added to the DC motor model, and a PI controller is used to realize the coordinated control of the left and right wheels; a four-wheel independent drive electric vehicle straight-line control simulation model is built in Simulink to verify the feasibility of the front-rear wheel group synchronous control algorithm based on speed deviation.

2. The linear motion synchronization control method of a four-wheel independent drive electric vehicle according to claim 1, characterized by, The process of calculating the difference signal and outputting the control signal by the PI controller comprises the following steps: The rotational speeds of the left and right wheels are detected in real time, and the speed difference between the left and right wheels is calculated; the speed difference is used as the input signal of the PI controller; The proportional gain is multiplied by the speed difference to obtain the output of the proportional part; The integral gain is multiplied by the integral of the speed difference to obtain the output of the integral part; The outputs of the proportional part and the integral part are added to obtain the total output signal of the PI controller, and the total output signal is used as the control signal and acts on the motor controllers of the left and right wheels; the motor controllers of the left and right wheels adjust the output torque or speed of the motor according to the received control signal to reduce the speed difference; through continuous adjustment, the rotational speeds of the left and right wheels tend to be consistent, achieving maximum approximation; The speed difference is continuously detected and fed back to the PI controller, and the PI controller continuously adjusts the control output according to the feedback signal.

3. The linear motion synchronization control method of a four-wheel independent drive electric vehicle according to claim 2, characterized by, The process of adjusting the output torque or speed of the motor comprises the following steps: After receiving the control signal from the PI controller, the motor controller analyzes the strength of the signal; according to the analyzed signal strength, the motor controller sets a reference torque or speed, which is calculated based on the current operating state of the motor and the target speed difference; If the signal strength indicates that the torque needs to be adjusted, the motor controller adjusts the electromagnetic torque of the motor by changing the current or voltage of the motor; If the signal strength indicates that the speed needs to be adjusted, the motor controller adjusts the speed of the motor by changing the supply frequency or voltage of the motor; The motor controller continuously monitors the actual output torque or speed of the motor and compares it with the set reference value; If there is a deviation, the motor controller fine-tunes the current, voltage, or frequency according to the size and direction of the deviation; when the output torque or speed of the motor reaches the expected value, the motor controller enters a steady-state maintenance mode, continuously monitors and fine-tunes the operating state of the motor.

4. The linear motion synchronization control method of a four-wheel independent drive electric vehicle according to claim 3, characterized by, The process of adjusting the torque and speed comprises the following steps: The difference between the target torque and the actual torque is calculated, the difference between the target torque and the actual torque is multiplied by the proportional gain, and the integral of the difference is multiplied by the integral gain to obtain the torque signal strength; The difference between the target speed and the actual speed is calculated, and the speed signal strength is determined by multiplying the difference by the proportional gain and adding the integral of the difference multiplied by the integral gain; The torque signal strength and the speed signal strength are compared; if the torque signal strength is greater than the speed signal strength, and torque control is the current priority, then the torque will be adjusted; otherwise, if the speed signal strength is greater than the torque signal strength, and speed control is the current priority, then the speed will be adjusted.

5. The linear motion synchronization control method of a four-wheel independent drive electric vehicle according to claim 1, characterized by, The process of achieving coordinated four-wheel speed through independent PI control of each drive wheel includes the following steps: Real-time speed data of the front and rear wheel groups is obtained through sensors installed on each wheel; the speed difference between the front and rear wheel groups is calculated, and the difference is the control variable, reflecting the possible speed inconsistency between the front and rear wheel groups during driving; Based on the calculated speed difference, a corresponding control signal is generated through multiple PI controllers; The PI controller adjusts the motor output of each drive wheel according to the size and trend of the speed difference, suppressing the speed difference between the front and rear wheel groups; The motor of each drive wheel receives the control signal from the PI controller and adjusts its speed according to the control signal, effectively coordinating the speed control of the front and rear wheel groups; the speed of the front and rear wheel groups is continuously monitored, and the parameters of the PI controller are dynamically adjusted as needed.

6. The linear motion synchronization control method of a four-wheel independent drive electric vehicle according to claim 5, wherein The process of adjusting the motor output of each drive wheel includes the following steps: Real-time monitoring of the speed of the front and rear wheel groups is performed, and the speed difference is calculated; The calculated speed difference is multiplied by the proportional gain to obtain the proportional control signal, and the proportional gain is adjusted according to the dynamic characteristics of the system and the desired response speed; The generated proportional control signal acts on the motor to adjust the output torque of the motor, reducing the speed difference; The proportional control signal is converted into a corresponding voltage or current signal by the motor controller to drive the motor to adjust its output torque.

7. The linear motion synchronization control method of a four-wheel independent drive electric vehicle according to claim 6, characterized by, The process of obtaining the proportional control signal includes the following steps: A reference model is set, which is an ideal linear system; the motor controller consists of a feedforward controller and a feedback controller; the feedforward controller is used to compensate for dynamic characteristics, and the feedback controller is used to reduce errors; An adaptive law is designed using Lyapunov stability theory to obtain the rate of change of the feedforward controller and feedback controller parameters; The closed-loop transfer function considers the effects of the feedforward controller and feedback controller, showing the relationship between the output and input; by adjusting the controller parameters, the dynamic response is optimized.

8. The linear motion synchronization control method of a four-wheel independent drive electric vehicle according to claim 1, characterized by, The process of building a four-wheel independent drive electric vehicle straight-line control simulation model in Simulink includes the following steps: Open Simulink and create a new model file; in the Simulink Library Browser, find and add 4 DC Motor blocks, representing the four drive wheels of the electric vehicle; configure the parameters for each motor block; Add a PI controller for each motor module to control the speed of the motor; the PI controller will adjust the output of the motor according to the speed difference signal; calculate the speed difference between the front and rear wheel groups and input it as a control signal into the corresponding PI controller to suppress the differential speed between the front and rear wheel groups; add a drive and set value module to set the target speed of each motor; provide the corresponding speed set value for each motor according to the linear motion requirements of the vehicle; Connect the speed output of each motor to the corresponding PI controller, connect the output of the PI controller to the input of the motor, and connect the output of the front and rear signal processing modules to the corresponding PI controller; connect the output of the drive and set value module to the speed set end of each motor; set the simulation time and step parameters, run the simulation model, and observe the speed synchronization of the four-wheel independent drive electric vehicle in linear motion.

9. The linear motion synchronization control method of a four-wheel independent drive electric vehicle according to claim 8, characterized by, The visualization process of running the simulation model includes the following steps: Connect the speed output signal of each motor to the corresponding oscilloscope module, and connect the speed output signal of all motors to a multi-input oscilloscope module; Configure the parameters of the oscilloscope module, set the time range and display mode; Run the simulation and observe the results, display the speed curve of each motor in real time, check whether the speed of each motor is synchronized, and whether there is a significant speed difference.

10. A linear motion synchronous control system for a four-wheel independent drive electric vehicle, characterized in that, Contains: In-wheel synchronization control module, responsible for adding the speed difference between the left and right wheels as a reference variable to the closed-loop control of the motor, calculating the difference signal through the PI controller and outputting the control signal to make the speed of the left and right drive wheels approximate to the maximum extent; Inter-wheel synchronization control module, responsible for controlling the speed difference between the front and rear wheel groups by taking the speed difference between the front and rear wheel groups as the controlled variable, suppressing the differential speed between the front and rear wheel groups, and achieving four-wheel speed coordination through independent PI control of each drive wheel; Motion simulation verification module, responsible for building a left and right wheel DC motor deviation control simulation model to verify the feasibility of the left and right wheel synchronization control algorithm based on speed deviation; by adding a left and right wheel speed coupling term to the DC motor model and implementing left and right wheel cooperative control through the PI controller; build a four-wheel independent drive electric vehicle linear control simulation model in Simulink to verify the feasibility of the front and rear wheel group synchronization control algorithm based on speed deviation.

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