A method for synchronous control of dual-motor drive system based on adaptive disturbance observer

Abstract

The present invention discloses a method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer, and the specific steps include: constructing a dynamic equation of a permanent magnet synchronous motor; redefining the state variables of the permanent magnet synchronous motor and rewriting them into a standard state equation according to the dynamic equation; introducing a sliding mode variable according to the standard state equation, designing an adaptive disturbance observer in combination with an adaptive law, and accurately estimating the disturbance; feeding back the observation result to a controller for disturbance compensation, designing a multiple sliding surface controller for a single motor speed control system, and performing synchronous control of the dual motors. The adaptive disturbance observer used in the present invention is combined with a sliding mode control technology to effectively solve the problems of nonlinearity, model uncertainty, and external disturbances in the dual-motor drive system, thereby significantly improving the stability and robustness of the system, maintaining the stable operation of the system under a wider range of operating conditions, and reducing the risk of performance degradation of the system due to disturbances.

Description

Technical Field

[0001] The invention belongs to the technical field of motor drive, and in particular relates to a method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer. Background Art

[0002] At present, the research on multi-motor speed synchronization system mainly focuses on two aspects: control strategy and control structure. In terms of control strategy, the traditional PID (Proportional Integral Derivative) control system has a simple structure, is easy to adjust, and is widely used. However, due to the inherent nonlinearity and strong coupling characteristics of the permanent magnet synchronous motor servo system itself, coupled with the fact that the operation process is often accompanied by strong external disturbances and its own parameter uncertainty, it is difficult to meet high-performance control for application scenarios with high performance and precision requirements by relying solely on PID control. For this reason, many modern control methods have been applied to the field of motor control, such as sliding mode control, adaptive control, optimal control, etc., which have improved the control performance of permanent magnet synchronous motors from different aspects. Among them, sliding mode control has good robustness to disturbances and uncertainties, and is widely used in motor control.

[0003] The basic idea of ​​sliding mode control is to design a sliding surface and a control law so that the system state can quickly reach and remain on the sliding surface, thereby achieving precise control of the system state. However, existing sliding mode control has the following disadvantages: (1) Dependence on model accuracy: Existing control methods are often based on precise mathematical models. However, the actual dual-motor drive system may have complex nonlinear characteristics and uncertainties, which makes it difficult for traditional control strategies to achieve the expected performance in practical applications.

[0004] (2) Insufficient robustness to external disturbances: Although the sliding mode control method can improve the system's robustness to disturbances, when there are unknown matching disturbances, the control effect of the existing technology may be affected, resulting in a decrease in system performance.

[0005] (3) Trade-off between control accuracy and response speed: When improving control accuracy, the response speed of the system is often sacrificed, and vice versa. Existing technologies make it difficult to achieve fast dynamic response while ensuring high accuracy.

[0006] (4) Difficulty in adjusting control parameters: Many existing control strategies require careful adjustment of control parameters to suit specific working conditions. This process is time-consuming and requires expertise, and once the working conditions change, the parameters may need to be readjusted. Summary of the invention

[0007] In order to make up for the deficiencies of the prior art, the present invention aims to provide a method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer, based on a cross-coupling structure and a sliding mode control method, and utilizing speed synchronization to improve the synchronous control capability of the system.

[0008] The technical problem solved by the present invention can be achieved through the following technical solutions: The method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer comprises the following specific steps: Step 1: Construct the dynamic equation of permanent magnet synchronous motor; Step 2: Based on the dynamic equation of step 1, redefine the state variables of the permanent magnet synchronous motor and rewrite it into the standard state equation; Step 3: According to the standard state equation in step 2, the sliding mode variable is introduced, and the adaptive disturbance observer is designed in combination with the adaptive law to accurately estimate the disturbance; Step 4: Feed the observation results of step 3 back to the controller for disturbance compensation, design a multiple sliding surface controller for the single motor speed control system, and perform synchronous control of the dual motors.

[0009] Furthermore, the kinetic equation in step 1 is: (1) Among them, i=1,2 represents two drive motors; are the angular positions of the two drive motors, is the angular acceleration of the two drive motors, are the angular velocities of the two drive motors, is the angular position of the load, is the angular velocity of the load, is the angular acceleration of the load; and is the rotational inertia of the drive motor and the load; are the control inputs for the two motors, is the motor viscous friction coefficient, is the friction torque; It represents the transmission torque between the two torque generators and the load, expressed as: (2) in, , and are the torsion coefficient and damping coefficient respectively; is the angle difference between the motor angle position and the load angle position, is the change in the angle difference between the motor position and the load angle position, is a friction function, Represents the rate of change of the friction function.

[0010] Furthermore, in step 2, a single motor model is selected, and , , the standard state equation of the nth-order nonlinear uncertain controlled object is: (3) In the formula, , is the load angular velocity, is the acceleration of the load; J is a positive constant and an intermediate variable; d is the uncertainty caused by model reduction and external disturbance. Formula (3) is used to develop a tracking controller for the motor.

[0011] Furthermore, in step 3, the observer estimates the unknown matching disturbance in the system in real time using an adaptive algorithm by measuring the output of the system and the known system input. The design of the observer is based on the sliding mode principle, as follows: (4) In the formula, To estimate the results, an auxiliary function is designed to make the sliding mode variable tends to 0; and are auxiliary variables and auxiliary functions, respectively, and gain parameters and Designed for: (5) In the formula, , All are normal numbers.

[0012] Furthermore, in step 4, a sliding mode variable is introduced into the observer , by designing the controller and adjusting the observer gain , , which can make the sliding mode variable tends to 0, by observing Knowing this , which can be calculated from formula (4) To achieve the actual disturbance The approach.

[0013] Furthermore, in step 4, the synchronous control strategy of the dual motors is as follows: Design a synovial surface: (6) The arrival law is designed as: (7) The second sliding surface is expressed as: (8) From the dual motor system, we get: (9) in, , , are sliding surface parameters to be adjusted; is the first sliding surface, θ 1 and θ 2 All are state variables; is the derivative of the first sliding surface, is the second sliding surface, u i are the control inputs for the two motors, Indicates the transmission torque between the two torques and the load, J m is the rotational inertia of the drive motor.

[0014] Furthermore, the synchronous controller is designed as follows: (10) in, is the tuning parameter, u i are the control inputs for the two motors, Indicates the transmission torque between the two torques and the load, is the angular velocity of the two drive motors, J m is the moment of inertia of the drive motor, b m is the motor viscous friction coefficient.

[0015] Compared with the prior art, the present invention has the following advantages: (1) The adaptive disturbance observer combined with the sliding mode control technology adopted in the present invention effectively solves the problems of nonlinearity, model uncertainty and external disturbance in the dual-motor drive system, thereby significantly improving the stability and robustness of the system, and can maintain stable operation of the system under a wider range of operating conditions, reducing the risk of performance degradation caused by disturbances.

[0016] (2) The finite-time stable adaptive disturbance observer designed by the present invention can accurately estimate and compensate for the unknown matching disturbance in the system, thereby achieving higher trajectory tracking accuracy and synchronization. The tracking error can approach zero after the observer converges, which greatly improves the tracking accuracy of the system and meets the high-precision control requirements.

[0017] (3) The present invention adopts a sliding mode controller designed with multi-sliding surface technology, which not only effectively solves the tracking and synchronization control problems, but also improves the control efficiency, can respond to system changes more quickly, and reduces the delay in the control process, thereby improving the response speed and operation efficiency of the entire system.

[0018] (4) The design of the present invention simplifies the control structure of the system and reduces the additional hardware requirements, thereby reducing the overall cost and complexity of the system; while maintaining high performance, it reduces the maintenance and operating costs of the system, making the technology more economical and feasible. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of the method of the present invention; Figure 2 This is a working diagram of the system of the present invention; Figure 3 This is a working diagram of the sliding mode controller of the present invention; Figure 4 This is a block diagram of the dual-motor drive system of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] like Figure 1 As shown, a method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer comprises the following specific steps: Step 1: Construct the dynamic equations of the permanent magnet synchronous motor.

[0022] The specific dynamic equation of the permanent magnet synchronous motor is: (1) Among them, i=1,2 represents two drive motors; are the angular positions of the two drive motors, is the angular acceleration of the two drive motors, are the angular velocities of the two drive motors, is the angular position of the load, is the angular velocity of the load, is the angular acceleration of the load; and is the rotational inertia of the drive motor and the load; are the control inputs for the two motors, is the motor viscous friction coefficient, is the friction torque; It represents the transmission torque between the two torque generators and the load, expressed as: (2) in, , and are the torsion coefficient and damping coefficient respectively; is the angle difference between the motor angle position and the load angle position, is the change in the angle difference between the motor position and the load angle position, is a friction function, Represents the rate of change of the friction function.

[0023] Step 2: Based on the dynamic equation of step 1, redefine the state variables of the permanent magnet synchronous motor and rewrite it into the standard state equation.

[0024] In order to facilitate calculation, the present invention selects a single motor model and sets , , the standard state equation of the n-order nonlinear uncertain controlled object is: (3) In the formula, , is the load angular velocity, is the acceleration of the load; J is a positive constant and an intermediate variable; d is the uncertainty caused by model reduction and external disturbance. Formula (3) is used to develop a tracking controller for the motor.

[0025] Step 3: According to the standard state equation in step 2, the sliding mode variable is introduced, and the adaptive disturbance observer is designed in combination with the adaptive law to accurately estimate the disturbance.

[0026] The main idea of ​​the adaptive disturbance observer (ADO) is to design a sliding variable that connects the estimated disturbance to the system state, and the adaptive law is designed in the form of a hypertorsion structure. Unlike other sliding mode observers, the proposed observer does not use the information of the upper bound of the disturbance, but only assumes that the disturbance is bounded by an unknown boundary.

[0027] like Figure 2 and Figure 3 As shown in the figure, the observer uses an adaptive algorithm to estimate the unknown matching disturbance in the system in real time by measuring the output of the system and the known system input. The design of the observer is based on the sliding mode principle to ensure accurate estimation of the disturbance within a limited time. The details are as follows: (4) In the formula, To estimate the results, an auxiliary function is designed to make the sliding mode variable tends to 0; is a sliding variable, and are auxiliary variables and auxiliary functions, respectively, and gain parameters and Designed for: (5) In the formula, , All are normal numbers.

[0028] Step 4: Feed the observation results of step 3 back to the controller for disturbance compensation, design a multiple sliding surface controller for the single motor speed control system, and perform synchronous control of the dual motors.

[0029] like Figure 4 As shown, the controller uses multiple sliding surfaces to deal with different dynamic characteristics of the system respectively, and by designing appropriate control laws, it ensures that the system state can reach and stabilize on the sliding surface within a limited time.

[0030] For the dual-motor drive system, the synchronization of the drive motors is essential. Even if the same type of drive motors are selected, there will be position errors due to gear clearance, measurement errors and external interference. In order to avoid potential problems, a synchronization control strategy is embedded in the tracking controller of the dual-motor drive system. The synchronization control strategy of the dual motors is as follows: Design a synovial surface: (6) The arrival law is designed as: (7) in, , ; The second sliding surface is expressed as: (8) From the dual motor system, we get: (9) The synchronous controller is designed as follows: (10) in, , are the sliding surface parameters to be adjusted; To tune the parameters, is the first sliding surface, θ 1 and θ 2 All are state variables; is the derivative of the first sliding surface, is the second sliding surface, ui are the control inputs for the two motors, Indicates the transmission torque between the two torques and the load, is the angular velocity of the two drive motors, J m is the driving motor moment of inertia, b m is the motor viscous friction coefficient.

[0031] The present invention has significant advantages in improving system stability, tracking accuracy and control efficiency through its unique technical solution, while reducing cost and complexity, and provides an effective solution for the precise control of the dual-motor drive system. The specific proof process is as follows: Define a vector, , known , , , The derivative of : , (a) It can be seen that (b) The selected Lyapunov function is (c) , are all normal numbers, is a positive definite matrix.

[0032] Lyapunov's derivative is: (d) in, It is expressed as: (e) Also because (f) so (g) Assuming the wave excitation force is bounded, then the normal Total satisfaction ,therefore, (h) in, It is expressed as: (i) Substituting formula (5) into the equation, we can obtain: (j) Therefore, when , the following formula holds: (k) In the formula, and represents the smallest and largest eigenvalues ​​of the matrix, since Established, if , we can conclude , ;once Established, then , that is, as the Lyapunov function decreases, the error of model estimation also decreases. Using the finite time theorem, the convergence time of the algorithm is: (l) By adjusting the two auxiliary functions, the sliding surface It tends to 0, and the real-time estimation of the system is completed in less than T.

[0033] The above formula (a) is derived in the process of constructing an adaptive disturbance observer (ADO) in order to analyze the finite-time stability of the observer. Through such an expression, the relationship between the system state and the estimated disturbance can be further analyzed, preparing for the subsequent stability analysis using the Lyapunov function; the derivative expression in formula (b) is organized into a matrix form to facilitate the subsequent analysis using the Lyapunov stability theory. The matrix form can clearly represent the dynamic relationship between the system state and the disturbance d, which is a key step in analyzing the stability of the adaptive disturbance observer; the Lyapunov function in formula (c) plays an important role in analyzing the stability of the system. By selecting a suitable Lyapunov function and analyzing the properties of its time derivative, it can be determined whether the system is stable; the Lyapunov function constructed by the P matrix is ​​selected for the subsequent analysis of the stability of the adaptive disturbance observer. The derivation of formula (d) is based on Lyapunov stability theory. The stability of the system is determined by calculating Lyapunov's time derivative. The Q matrix is ​​an intermediate matrix that appears in the derivation process, which reflects the influence of the disturbance d on the Lyapunov time derivative. Formula (e) is obtained in the process of calculating the Lyapunov time derivative. Its elements are related to the previously defined parameters L1 and L2 as well as and The properties of the Q matrix play an important role in judging the positivity of Lyapunov's time derivative, which in turn affects the judgment of the stability of the system; Formula (f) is an intermediate result in the process of simplifying Lyapunov's time derivative. Linking with a new vector G helps to further simplify Lyapunov's time derivative expression, so as to better analyze the system stability. Formula (g) more concisely expresses the relationship between Lyapunov's time derivative and system state, disturbance d, and the correlation matrix Q and vector G. Through this expression, it is more convenient to analyze the stability of the system in the presence of disturbance. Formula (h) takes into account the boundedness of the disturbance. By introducing the J matrix, the Lyapunov time derivative expression is further adjusted so that the stability of the system can be judged according to the properties of the Q+J matrix. The matrix in formula (i) is introduced under the consideration of the boundedness of the disturbance, and its elements are related to the disturbance d and the previously defined λ. The properties of the Q+J matrix obtained by adding the J matrix to the Q matrix play a key role in judging the positivity of the Lyapunov time derivative, thereby affecting the judgment of the system stability; the matrix in formula (j) is obtained by adding the Q matrix to the J matrix under the consideration of the boundedness of the disturbance.

[0034] It is very important to judge the positivity of Lyapunov's time derivative, and thus the stability of the adaptive disturbance observer. All parameters in the proof process are randomly listed and arbitrarily obtained, and have no practical significance. The main purpose is to prove the conclusion of convergence within a finite time T.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer, characterized in that: The specific steps include: Step 1: Construct the dynamic equation of permanent magnet synchronous motor; Step 2: Based on the dynamic equation of step 1, redefine the state variables of the permanent magnet synchronous motor and rewrite it into the standard state equation; Step 3: According to the standard state equation in step 2, the sliding mode variable is introduced, and the adaptive disturbance observer is designed in combination with the adaptive law to accurately estimate the disturbance; Step 4: Feed the observation results of step 3 back to the controller for disturbance compensation, design a multiple sliding surface controller for the single motor speed control system, and perform synchronous control of the dual motors.

2. The method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer according to claim 1, characterized in that: The kinetic equation in step 1 is: （1） Among them, i=1,2 represents two drive motors; are the angular positions of the two drive motors, is the angular acceleration of the two drive motors, are the angular velocities of the two drive motors, is the angular position of the load, is the angular velocity of the load, is the angular acceleration of the load; and is the rotational inertia of the drive motor and the load; are the control inputs for the two motors, is the motor viscous friction coefficient, is the friction torque; It represents the transmission torque between the two torque generators and the load, expressed as: （2） in, , and are the torsion coefficient and damping coefficient respectively; is the angle difference between the motor angle position and the load angle position, is the change in the angle difference between the motor position and the load angle position, is a friction function, Represents the rate of change of the friction function.

3. The method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer according to claim 2, characterized in that: In step 2, a single motor model is selected. , , the standard state equation of the n-order nonlinear uncertain controlled object is: （3） In the formula, , is the load angular velocity, is the acceleration of the load; J is a normal number and an intermediate variable; d is the uncertainty caused by model reduction and external disturbance. Formula (3) is used to develop a tracking controller for the motor.

4. The method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer according to claim 3 is characterized in that: In step 3, the observer estimates the unknown matching disturbance in the system in real time using an adaptive algorithm by measuring the output of the system and the known system input. The design of the observer is based on the sliding mode principle, as follows: （4） In the formula, To estimate the results, an auxiliary function is designed to make the sliding mode variable tends to 0; and are auxiliary variables and auxiliary functions, respectively, and gain parameters and Designed for: （5） In the formula, , All are normal numbers.

5. The method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer according to claim 4, characterized in that: In step 4, a sliding mode variable is introduced into the observer , by designing the controller and adjusting the observer gain , , which can make the sliding mode variable tends to 0, by observing Knowing this , which can be calculated from formula (4) To achieve the actual disturbance The approach.

6. The method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer according to claim 5, characterized in that: In step 4, the synchronous control strategy of the dual motors is as follows: Design a synovial surface: (6) The arrival law is designed as: (7) The second sliding surface is expressed as: (8) From the dual motor system, we get: (9) in, , , are sliding surface parameters to be adjusted; is the first sliding surface, θ 1 and θ 2 All are state variables; is the derivative of the first sliding surface, is the second sliding surface, u i are the control inputs for the two motors, Indicates the transmission torque between the two torques and the load, J m is the rotational inertia of the drive motor.

7. The method for synchronous control of a dual-motor drive system based on an adaptive disturbance observer according to claim 6, characterized in that: The synchronous controller is designed as follows: (10) in, is the tuning parameter, u i are the control inputs for the two motors, Indicates the transmission torque between the two torques and the load, is the angular velocity of the two drive motors, J m is the moment of inertia of the drive motor, b m is the motor viscous friction coefficient.

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