Synchronous control method for double-drive motion system based on synchronous error self-adaptive compensation

Abstract

The invention relates to a synchronous control method for a double-drive motion system based on synchronous error self-adaptive compensation, and belongs to the field of intelligent manufacturing. Firstly, a self-adaptive synchronous control system is designed, and a parallel synchronous control architecture is adopted to organize two single-axis speed tracking control loops and a synchronous error compensation control loop which comprise a speed-current cascade closed-loop controller, a tracking performance comparison switch, a synchronous error compensator and the like. Secondly, a real-time synchronous error selective compensation strategy is designed, a weak tracking performance motor is recognized through a tracking performance comparison switch, and a synchronous speed error is converted into a current compensation signal of a current closed-loop controller through a synchronous error compensator; and finally, designing a single-axis tracking-double-axis synchronous composite motion controller, wherein the single-axis tracking-double-axis synchronous composite motion controller comprises a speed closed-loop controller adopting a sliding mode control method and a current closed-loop controller adopting a PID control method. According to the method, mutual promotion of tracking performance of the two motors is facilitated, and single-axis tracking performance and double-axis synchronous movement can be considered.

Description

Technical Field

[0001] The present invention relates to the field of intelligent manufacturing, and in particular to a synchronous control method for a dual-drive motion system based on adaptive compensation of synchronization errors. Background Art

[0002] Synchronous control is one of the key technologies for dual-drive motion systems to achieve high-speed and high-precision positioning control. It is used to improve the dynamic performance of the drive motor and its robustness against nonlinear interference. It is often used in the field of intelligent manufacturing, such as automated production equipment, intelligent transportation, and mechanical positioning. Commonly used synchronous control methods mainly include parallel synchronous control, master-slave synchronous control, and cross-coupling control. Parallel synchronous control maintains synchronization performance by controlling the tracking accuracy of the two motors to the reference input separately, but there is no direct connection between the two motors, so the synchronization performance is poor. Master-slave synchronous control is to input the reference signal into the master motor and the output of the master motor as the input of the slave motor to form a series control mode, but this mode may cause the actual output to deviate from the expected signal due to the accumulation of error transmission. Cross-coupling control compensates the synchronization error to each motor when the two motors are independently controlled, which has the potential effect of averaging the strong and weak tracking performance of the two motors. It may focus on the motion synchronization between the two motors and weaken the original tracking performance of each motor. Summary of the invention

[0003] In order to solve the limitations of the above three dual-drive motion system synchronization control methods, this paper invents a dual-drive motion system synchronization control method based on adaptive compensation of synchronization error. By innovatively designing a selective compensation strategy, the synchronization error is compensated in real time to the controller input of the motor with weak tracking performance at the current moment, and the synchronization error is compensated in combination with the sliding mode controller, and the tracking error is feedback controlled. This can not only improve the synchronization of the two motors, but also ensure the tracking performance of each motor for its own target signal, which is beneficial to the high-speed and high-precision positioning control of the dual-drive motion system.

[0004] The present invention is achieved through the following technical solutions:

[0005] A dual-drive motion system synchronization control method based on synchronization error adaptive compensation includes the following steps:

[0006] Step 1: Adaptive synchronous control system design: First, design a parallel synchronous control architecture, which is used to organize two single-axis speed tracking control loops and a synchronous error compensation control loop; second, design a single-axis speed tracking control loop, using a cascade closed-loop controller that combines speed closed-loop control with current closed-loop control; third, design a synchronous error compensation control loop, including a synchronous error calculation module, a tracking performance comparison switch, and a synchronous error compensator;

[0007] Step 2: Design method of real-time synchronization error selective compensation strategy: First, design a tracking performance comparison switch to distinguish the two motors according to strong tracking performance and weak tracking performance at each sampling cycle; second, design a synchronization error calculation module to obtain the synchronization speed error by calculating the difference between the actual speed signals of the two motors; third, design a synchronization error compensator to convert the synchronization speed error into a current compensation signal of the current closed-loop controller for motors with weak tracking performance;

[0008] Step 3: Design of single-axis tracking-dual-axis synchronous composite motion controller: First, establish the dynamic model of the dual-drive motion system; secondly, design a single-axis tracking motion controller, and use the speed error signal as input to perform speed closed-loop control; thirdly, design a dual-axis synchronous motion controller, and use the current error signal as input to perform current closed-loop control, thereby completing single-axis tracking-dual-axis synchronous composite motion control.

[0009] Furthermore, the adaptive synchronous control system design method comprises the following steps:

[0010] Step 1.1: Parallel synchronous control architecture design: A parallel synchronous control architecture is used to organize two single-axis speed tracking control loops, wherein the two control loops receive the same target speed signal input but operate independently; the output ends of the two single-axis speed tracking control loops are connected to the input end of the synchronous error compensation control loop, and the actual speed signals and actual position signals output by the two motors are processed by the synchronous error compensation control loop and input into the single-axis speed tracking control loop in the form of current compensation instructions;

[0011] Step 1.2: Design of single-axis speed tracking control loop: The single-axis speed tracking control loop adopts a cascade closed-loop controller that combines speed closed-loop control with current closed-loop control. The control loop also includes a vector controller (Field-Oriented Controller, FOC), an inverter drive and a linear motor; the target speed signal is input into the cascade closed-loop controller, and the voltage signal processed by the controller is converted into a pulse signal by the vector controller to control the inverter drive to drive the linear motor to move, and the actual current signal generated by the linear motor movement is fed back to the input end of the current closed-loop controller, and the actual speed signal generated by the linear motor movement is fed back to the input end of the speed closed-loop controller;

[0012] Step 1.3: Design of synchronous error compensation control loop: The synchronous error compensation control loop consists of a synchronous error calculation module, a tracking performance comparison switch and a synchronous error compensator; the actual speed signals generated by the movement of the two motors are processed into synchronous speed errors by the synchronous error calculation module, and the actual position signals generated by the movement of the two motors are processed by the tracking performance comparison switch (TPCS) to obtain a switch control signal, which controls the selective compensation switch of the synchronous speed error, and outputs the synchronous speed error to the synchronous error compensator of the corresponding compensation object. After speed compensation processing, it is input into the current closed-loop controller input end of the single-axis speed tracking control loop of the corresponding compensation object in the form of current compensation instructions.

[0013] Furthermore, the real-time synchronization error selective compensation strategy design method comprises the following steps:

[0014] Step 2.1: Tracking performance comparison switch design: Design a tracking performance comparison switch for evaluating the tracking performance of two motors. The switch uses the absolute position error and mean square position error between the actual position signal of each motor and the target position signal as the judgment basis. As shown in formula (1), the two motors are distinguished as strong tracking performance and weak tracking performance at each sampling cycle: first, the absolute position errors of the two motors are judged, and the motor with a large absolute position error is regarded as weak tracking performance; if the absolute position errors of the two motors are equal, the mean square position error is judged, and the motor with a large mean square position error is regarded as weak tracking performance; if the absolute position errors and mean square position errors of the two motors are equal, one motor is randomly selected as weak tracking performance; and the weak tracking performance motor is taken as the compensation object to determine the switch control signal of the tracking performance comparison switch;

[0015]

[0016] Among them, S ref is the target position signal, S i is the actual position signal of motor number i, e s is the absolute position error, MSE is the mean square position error, τ is the current time, and t is the running time;

[0017] Step 2.2: Synchronous error calculation module design: The synchronous error calculation module obtains the synchronous speed error E by calculating the difference between the actual speed signals of the two motors. v , the error is equal to the actual speed V of the motor with strong tracking performance 强 Subtract the actual speed V of the motor with weak tracking performance 弱 :

[0018] E v =V强 -V 弱 (2)

[0019] Step 2.3: Design of synchronous error compensator: The synchronous error compensator is divided into speed compensator 1 and speed compensator 2 according to the motor number i. The synchronous speed error is input into the speed compensator of the corresponding compensation object through the tracking performance comparison switch, and then processed by the speed compensation method of the sliding mode control method to generate the current compensation signal of the current closed-loop controller in the corresponding compensation object.

[0020] Furthermore, the single-axis tracking-dual-axis synchronization composite motion controller design comprises the following steps:

[0021] Step 3.1: Modeling method of dual-drive motion system: First, establish the dynamic equation of the motor of the dual-drive motion system: as shown:

[0022] F m =F a +F f +F d (3)

[0023] Among them, F m is the driving force, F a is the inertial force, F f is the viscous friction, F d are other disturbance forces, which are ignored in the modeling stage;

[0024] The driving force model is established based on the voltage balance equation and flux linkage model of the permanent magnet synchronous motor:

[0025]

[0026] Where C is the motor driving force constant, P n is the number of motor pole pairs, ψ f is the effective flux generated by the permanent magnet, σ is the pole pitch, and i is the driving current;

[0027] According to formulas (3) and (4), the dynamic model of the dual-drive motion system is established:

[0028]

[0029] Where B is the viscous friction coefficient, k is the motor number, m is the load mass, and m k is the primary mass of the motor, s(t) is the function of the linear motor position signal with respect to time, i(t) is the function of the linear motor current signal with respect to time;

[0030] Step 3.2: Design of single-axis tracking motion controller: The single-axis tracking motion controller is a speed closed-loop controller using a sliding mode control method. The controller input signal is a motor speed error signal, that is, the difference between the target speed signal and the actual speed signal. The current control command corresponding to the speed error signal is calculated by the sliding mode control method to realize single-axis tracking motion control, and the current control command is output to the input end of the current closed-loop controller;

[0031] Step 3.3: Design of dual-axis synchronous motion controller: The dual-axis synchronous motion controller is a current closed-loop controller using the PID control method. It integrates the current control command of the single-axis tracking motion controller and the current compensation information of the synchronous error compensator as the control target of the current loop, calculates the current error signal based on the actual current signal fed back by the inverter drive, and calculates the voltage control command corresponding to the current error signal through the PID control method to realize dual-axis synchronous motion control.

[0032] Further according to the sliding mode control method described in steps 2 and 3, the following steps are included:

[0033] Step 4.1: Sliding surface design: Sliding surface design is performed based on the motor dynamics model. First, the state quantities x1 and x2 are set:

[0034]

[0035] Among them, v ref is the target speed signal, v is the actual speed signal, is the state quantity x1 after derivation;

[0036] Combining formula (6) with formula (5), the system state space equation is established:

[0037]

[0038] Among them, the control input is u=i(t)′, and the mass sum of the load and the motor primary is M=m+m0;

[0039] Design sliding surface function based on system state space equation

[0040] s=cx1+x2 (8)

[0041] Among them, the design parameter c>0;

[0042] By differentiating formula (8), we can get the sliding surface derivative function:

[0043]

[0044] Step 4.2: Exponential approach rate design: According to the sliding surface function and the system state space equation, design the exponential approach rate used in the sliding mode control method:

[0045]

[0046] Among them, the design parameters ε>0, q>0; sgn() is the sign function;

[0047] Step 4.3: Sliding mode controller design: First, substitute the exponential approach rate formula (10) into the sliding surface derivative function formula (9) to establish a preliminary sliding mode controller:

[0048]

[0049] Substitute the control input u=i(t)′ into formula (11) to obtain the final sliding mode controller:

[0050]

[0051] Among them, i is the current control variable.

[0052] Compared with existing synchronous control technologies such as parallel synchronous control, master-slave synchronous control, and cross-coupling control, the present invention has at least the following beneficial effects or advantages:

[0053] (1) Compared with the parallel synchronous control method, the present invention overcomes the problem of poor synchronization when the two motors run independently.

[0054] (2) Compared with the master-slave synchronous control method, the present invention changes the traditional control mode in which the slave motor only tracks the motion state of the master motor and ignores the direct tracking of the target motion state, thereby overcoming the problem of increasing slave motor target tracking error due to error transmission accumulation.

[0055] (3) Compared with the cross-coupling control method, the present invention changes the potential processing mechanism for averaging the strong and weak tracking performances of the two motors, which is beneficial to the mutual promotion of the tracking performances of the two motors, and improves the target tracking performance of each motor while ensuring the motion synchronization between the two motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The present invention will be further described in detail below with reference to the accompanying drawings:

[0057] Figure 1 It is a step diagram of a synchronous control method of a dual-drive motion system based on adaptive compensation of synchronization error;

[0058] Figure 2 This is a diagram of the adaptive synchronization control architecture;

[0059] Figure 3 Flowchart of switches for tracking performance comparison;

[0060] Figure 4 This is the linear motor dynamics analysis diagram. DETAILED DESCRIPTION

[0061] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] The present invention provides a dual-drive motion system synchronization control method based on synchronization error adaptive compensation, such as Figure 1 The method specifically comprises the following steps:

[0063] Step 1: Adaptive synchronous control system design: Figure 2 As shown in , a parallel synchronous control architecture is adopted to organize two single-axis speed tracking control loops and a synchronous error compensation control loop, and the single-axis speed tracking control loop and the synchronous error compensation control loop are designed separately.

[0064] The parallel synchronous control architecture controls two single-axis speed tracking control loops to run independently and in parallel under the same target speed input signal, but the dual-drive synchronization performance of this architecture is poor. Therefore, the design connects the two single-axis speed tracking control loops through a synchronous error compensation control loop, so that the adaptive synchronous control system can take into account both single-axis accuracy and dual-drive synchronization; the design of the single-axis speed tracking control loop adopts a cascade closed-loop controller that combines speed closed-loop control with current closed-loop control; the design of the synchronous error compensation control loop includes a synchronous error calculation module, a tracking performance comparison switch and a synchronous error compensator.

[0065] Step 1.1: Design of parallel synchronous control architecture: Construct a parallel synchronous control architecture, give the same target input signal, and control the two single-axis speed tracking control loops to run independently; the input target speed signal is converted into the actual speed signal and actual position signal output by the two motors through loop processing, and the signal is processed by the synchronous error compensation control loop to generate a current compensation command input into the single-axis speed tracking control loop.

[0066] Step 1.2: Single-axis speed tracking control loop design: Use a cascade closed-loop controller combining the speed loop and the current loop to Figure 2 Target input speed signal V ref Perform calculations to generate a voltage control signal U q , the pulse signal PWM is obtained through the FOC algorithm, thereby controlling the inverter drive to drive the linear motor to move. The actual three-phase current i output by the inverter abcThe actual speed signals V1 and V2 output by the motor are fed back to the input of the speed loop controller to form a closed-loop control.

[0067] Step 1.3: Design of synchronous error compensation control loop: The loop consists of three parts: synchronous error calculation module, tracking performance comparison switch (TPCS) and synchronous error compensator. The actual speed signals V1 and V2 generated by the two motors in the single-axis speed tracking control loop in step 1.1 are processed by the synchronous error calculation module into synchronous speed error e v1 ,e v2 , the tracking performance comparison switch TPCS controls the conduction state of the synchronous speed error output route; TPCS processes the actual position output signals of the two motors and obtains the switch state parameter d, and opens the corresponding switch port 1 or 2 according to the parameter, that is, Figure 2 The on and off states of switches 1 and 2, ports 1 and 2 can only be turned on at the same time, the synchronous speed error is processed by the corresponding synchronous error compensator and input into the current loop controller input end of the single-axis speed tracking control loop of the corresponding compensation object in the form of current compensation instructions.

[0068] Step 2: Design method of real-time synchronization error selective compensation strategy: Design the algorithm of tracking performance comparison switch TPCS, stipulate that the strength of motor tracking performance is judged in each independent sampling cycle, and the judgment indicators are absolute position tracking error and mean square position error, so as to determine the compensation object; design a synchronization error calculation module to calculate the synchronous speed error value of the two motors; design a synchronization error compensator, and for motors with weak tracking performance, process the synchronous speed error value through compensator operation into a current compensation feedforward signal of the current loop controller.

[0069] Step 2.1: Tracking Performance Comparison Switch Design: Figure 3 As shown in the figure, a tracking performance comparison switch TPCS is designed to evaluate the tracking performance of two motors. The judgment index of the switch is set as the absolute position error and mean square position error between the actual position signal and the target position signal of each motor. As shown in formula (1), a real-time judgment is performed in each sampling cycle. If the judgment index is large, the tracking performance is weak, and the corresponding motor is used as the compensation object of the current cycle. If the index is small, the tracking performance is strong.

[0070]

[0071] Among them, S ref is the target position signal, S i is the actual position signal of motor number i, e s is the absolute position error, MSE is the mean square position error, τ is the current time, and t is the running time.

[0072] First, determine indicator 1: the absolute position error size e s , a motor with a small error means that the error between the target position and the actual position of the motor is small at the current moment, and the motor is regarded as having strong tracking performance, while the motor with weak tracking performance is regarded as the compensation object of the current cycle; if the absolute position error cannot be judged, that is, they are equal, then continue to compare the size of the mean square position error MSE to judge, the motor with a small mean square error is regarded as having strong tracking performance, while the motor with weak tracking performance is regarded as the compensation object of the current cycle; if the mean square error still cannot be judged, then motor 1 is assumed to be a motor with weak tracking performance and the compensation object; the above method can determine the switch opening state, that is, the value of d. When the d value is 1, the compensation object is motor 1, and port 1 of the switch is turned on. When the d value is 2, the compensation object is motor 2, and port 2 of the switch is turned on.

[0073] Step 2.2: Design of synchronous error calculation module: Design a synchronous error calculation module to calculate the difference between the actual speed signals of the two motors and obtain the synchronous speed error e v1 ,e v2 , the error value is equal to the actual speed V of the motor with strong tracking performance 强 Subtract the actual speed V of the motor with weak tracking performance 弱 , as shown in Formula 2.

[0074] E v =V 强 -V 弱 (2)

[0075] When motor 2 is a strong tracking motor and motor 1 is a weak tracking motor, V 强 is the speed of motor 2, i.e. V2, V 弱 is the speed of motor 1, i.e. V1, and the synchronous speed error is E v =e v1 =V2-V1. When motor 1 is a motor with strong tracking performance and motor 2 is a motor with weak tracking performance, then V 强 is the speed of motor 1, i.e. V1, V 弱 is the speed of motor 2, that is, V2. At this time, the synchronous speed error is E v =e v2 =V1-V2.

[0076] Step 2.3: Design of synchronous error compensator: The synchronous error compensator is divided into speed compensator 1 and speed compensator 2 according to the motor number i. The synchronous speed error is input into the speed compensator of the corresponding compensation object through the tracking performance comparison switch, and then processed by the speed compensation of the sliding mode control method to generate the current compensation signal of the current closed-loop controller in the corresponding compensation object.

[0077] When motor 2 is a motor with strong tracking performance and motor 1 is a motor with weak tracking performance, the value of d is 1, and switch port 1 is turned on. At this time, the synchronous speed error e v1 =V2-V1 enters speed compensator 1 for calculation, and outputs the calculated current compensation command to the current loop controller input of the single-axis speed tracking control loop where motor 1 is located; port 2 is disconnected, so the current loop compensation value of motor 2 is 0. When motor 1 is a strong tracking performance motor and motor 2 is a weak tracking performance motor, the d value is 2, and switch port 2 is turned on. At this time, the synchronous speed error e v2 =V1-V2 enters the speed compensator 2 for calculation, and outputs the calculated current compensation command to the current loop controller input end of the single-axis speed tracking control loop where the motor 2 is located, while port 1 is disconnected, so the current loop compensation value of the motor 1 is 0.

[0078] Step 3: Design of single-axis tracking-dual-axis synchronous composite motion controller: First, establish the dynamic model of the dual-drive motion system; secondly, design a single-axis tracking motion controller, and use the speed error signal as input to perform speed closed-loop sliding mode control; thirdly, design a dual-axis synchronous motion controller, and use the current error signal as input to perform current closed-loop PID control, thereby completing single-axis tracking-dual-axis synchronous composite motion control.

[0079] Step 3.1: Modeling method of dual-drive motion system: First, establish the dynamic equation of the dual-drive motion system motor, such as Figure 4 As shown: The formula is:

[0080] F m =F a +F f +F d (3)

[0081] Among them, F m is the driving force, F a is the inertial force, F f is the viscous friction, F d are other disturbance forces, which are ignored in the modeling stage.

[0082] The driving force model is established based on the voltage balance equation and flux linkage model of the permanent magnet synchronous motor:

[0083]

[0084] Where C is the motor driving force constant, P n is the number of motor pole pairs, ψ f is the effective flux generated by the permanent magnet, σ is the pole pitch, and i is the driving current.

[0085] According to formulas (3) and (4), the dynamic model of the dual-drive motion system is established:

[0086]

[0087] Where B is the viscous friction coefficient, k is the motor number, m is the load mass, and m k is the primary mass of the motor, s(t) is the position signal of the linear motor as a function of time, and i(t) is the current signal of the linear motor as a function of time.

[0088] Step 3.2: Design of single-axis tracking motion controller: Use the sliding mode control method as the speed closed-loop controller in the single-axis tracking motion controller. The difference between the target speed signal and the actual speed signal is converted into a corresponding current control command through the sliding mode control method, and the current control command is output to the input end of the current closed-loop controller to realize single-axis speed tracking control.

[0089] Step 3.3: Design of dual-axis synchronous motion controller: Use PID control method as the current closed-loop control method of the dual-axis synchronous motion controller. The input of the current controller combines the current control command of the single-axis tracking motion controller and the current compensation information of the synchronous error compensator. The current error signal is calculated based on the actual current signal fed back by the inverter drive. The voltage control command corresponding to the current error signal is calculated through the PID control method to realize dual-drive synchronous motion control between the two motors.

[0090] The sliding mode control method described in steps 2 and 3 comprises the following steps:

[0091] Step 4.1: Design the sliding surface: Design the sliding surface based on the motor dynamics model. First, set the state quantities x1 and x2:

[0092]

[0093] Among them, v ref is the target speed signal, and v is the actual speed signal.

[0094] Combining formula (6) with formula (5), the system state space equation is established:

[0095]

[0096] Among them, the control input is u=i(t)′, and the mass sum of the load and the motor primary is M=m+m0;

[0097] Design sliding surface function based on system state space equation

[0098] s=cx1+x2 (8)

[0099] Among them, the design parameter c>0.

[0100] By differentiating formula (8), we can get the sliding surface derivative function:

[0101]

[0102] Step 4.2: Design exponential approach rate: According to the sliding surface function and the system state space equation, design the exponential approach rate used by the sliding mode control method:

[0103]

[0104] Among them, parameters ε>0, q>0;

[0105] Step 4.3: Sliding mode controller design: First, substitute the exponential approach rate formula (10) into the sliding surface derivative function formula (9) to establish a preliminary sliding mode controller:

[0106]

[0107] Substituting the control input u=i(t)′ into formula (11), we get the sliding mode controller equation:

[0108]

[0109] Among them, i is the current control variable.

[0110] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A synchronous control method for a dual-drive motion system based on adaptive compensation of synchronization error, characterized in that The following steps are involved: Step 1: Adaptive synchronous control system design: First, design a parallel synchronous control architecture, which is used to organize two single-axis speed tracking control loops and a synchronous error compensation control loop; second, design a single-axis speed tracking control loop, using a cascade closed-loop controller that combines speed closed-loop control with current closed-loop control; third, design a synchronous error compensation control loop, including a synchronous error calculation module, a tracking performance comparison switch, and a synchronous error compensator; Step 2: Design method of real-time synchronization error selective compensation strategy: First, design a tracking performance comparison switch to distinguish the two motors according to strong tracking performance and weak tracking performance at each sampling cycle; Secondly, a synchronous error calculation module is designed to obtain the synchronous speed error by calculating the difference between the actual speed signals of the two motors; thirdly, a synchronous error compensator is designed to convert the synchronous speed error into a current compensation signal of the current closed-loop controller for motors with weak tracking performance; Step 3: Design of single-axis tracking-dual-axis synchronous composite motion controller: First, establish the dynamic model of the dual-drive motion system; secondly, design a single-axis tracking motion controller, and use the speed error signal as input to perform speed closed-loop control; thirdly, design a dual-axis synchronous motion controller, and use the current error signal as input to perform current closed-loop control, thereby completing single-axis tracking-dual-axis synchronous composite motion control.

2. The synchronous control method of a dual-drive motion system based on adaptive compensation of synchronization error according to claim 1, characterized in that: The adaptive synchronous control system design method comprises the following steps: Step 1.1: Parallel synchronous control architecture design: A parallel synchronous control architecture is used to organize two single-axis speed tracking control loops, wherein the two control loops receive the same target speed signal input but operate independently; the output ends of the two single-axis speed tracking control loops are connected to the input end of the synchronous error compensation control loop, and the actual speed signals and actual position signals output by the two motors are processed by the synchronous error compensation control loop and input into the single-axis speed tracking control loop in the form of current compensation instructions; Step 1.2: Design of single-axis speed tracking control loop: The single-axis speed tracking control loop adopts a cascade closed-loop controller combining speed closed-loop control and current closed-loop control. The control loop also includes a vector controller FOC, an inverter drive and a linear motor. The target speed signal is input into the cascade closed-loop controller. The voltage signal processed by the controller is converted into a pulse signal by the vector controller to control the inverter drive to drive the linear motor to move, and the actual current signal generated by the linear motor movement is fed back to the input end of the current closed-loop controller, and the actual speed signal generated by the linear motor movement is fed back to the input end of the speed closed-loop controller. Step 1.3: Design of synchronous error compensation control loop: The synchronous error compensation control loop consists of a synchronous error calculation module, a tracking performance comparison switch and a synchronous error compensator; the actual speed signals generated by the movement of the two motors are processed into synchronous speed errors by the synchronous error calculation module, and the actual position signals generated by the movement of the two motors are processed by the tracking performance comparison switch TPCS to obtain a switch control signal, which controls the selective compensation switch of the synchronous speed error, and outputs the synchronous speed error to the synchronous error compensator of the corresponding compensation object. After speed compensation processing, it is input into the current closed-loop controller input end of the single-axis speed tracking control loop of the corresponding compensation object in the form of a current compensation instruction.

3. The synchronous control method of a dual-drive motion system based on adaptive compensation of synchronization error according to claim 1, characterized in that: The real-time synchronization error selective compensation strategy design method comprises the following steps: Step 2.1: Tracking performance comparison switch design: Design a tracking performance comparison switch for evaluating the tracking performance of two motors. The switch uses the absolute position error and mean square position error between the actual position signal of each motor and the target position signal as the judgment basis. As shown in formula (1), the two motors are distinguished as strong tracking performance and weak tracking performance at each sampling cycle: first, the absolute position errors of the two motors are judged, and the motor with a large absolute position error is regarded as weak tracking performance; if the absolute position errors of the two motors are equal, the mean square position error is judged, and the motor with a large mean square position error is regarded as weak tracking performance; if the absolute position errors and mean square position errors of the two motors are equal, one motor is randomly selected as weak tracking performance; and the weak tracking performance motor is taken as the compensation object to determine the switch control signal of the tracking performance comparison switch; Among them, S ref is the target position signal, S i is the actual position signal of motor number i, e s is the absolute position error, MSE is the mean square position error, τ is the current time, and t is the running time; Step 2.2: Synchronous error calculation module design: The synchronous error calculation module obtains the synchronous speed error E by calculating the difference between the actual speed signals of the two motors. v , the error is equal to the actual speed V of the motor with strong tracking performance 强 Subtract the actual speed V of the motor with weak tracking performance 弱 : E v =V 强 -V 弱 (2) Step 2.3: Design of synchronous error compensator: The synchronous error compensator is divided into speed compensator 1 and speed compensator 2 according to the motor number i. The synchronous speed error is input into the speed compensator of the corresponding compensation object through the tracking performance comparison switch, and then processed by the speed compensation method of the sliding mode control method to generate the current compensation signal of the current closed-loop controller in the corresponding compensation object.

4. The synchronous control method of a dual-drive motion system based on adaptive compensation of synchronization error according to claim 1, characterized in that: The single-axis tracking-dual-axis synchronous composite motion controller design includes the following steps: Step 3.1: Modeling method of dual-drive motion system: First, establish the dynamic equation of the motor of the dual-drive motion system: as shown: F m =F a +F f +F d (3) Among them, F m is the driving force, F a is the inertial force, F f is the viscous friction, F d are other disturbance forces, which are ignored in the modeling stage; The driving force model is established based on the voltage balance equation and flux linkage model of the permanent magnet synchronous motor: Where C is the motor driving force constant, P n is the number of motor pole pairs, ψ f is the effective flux generated by the permanent magnet, σ is the pole pitch, and i is the driving current; According to formulas (3) and (4), the dynamic model of the dual-drive motion system is established: Where B is the viscous friction coefficient, k is the motor number, m is the load mass, and m k is the primary mass of the motor, s(t) is the function of the linear motor position signal with respect to time, i(t) is the function of the linear motor current signal with respect to time; Step 3.2: Design of single-axis tracking motion controller: The single-axis tracking motion controller is a speed closed-loop controller using a sliding mode control method. The controller input signal is a motor speed error signal, that is, the difference between the target speed signal and the actual speed signal. The current control command corresponding to the speed error signal is calculated by the sliding mode control method to realize single-axis tracking motion control, and the current control command is output to the input end of the current closed-loop controller; Step 3.3: Design of dual-axis synchronous motion controller: The dual-axis synchronous motion controller is a current closed-loop controller using the PID control method. It integrates the current control command of the single-axis tracking motion controller and the current compensation information of the synchronous error compensator as the control target of the current loop, calculates the current error signal based on the actual current signal fed back by the inverter drive, and calculates the voltage control command corresponding to the current error signal through the PID control method to realize dual-axis synchronous motion control.

5. The synchronous control method of a dual-drive motion system based on adaptive compensation of synchronization error according to claims 3 and 4 is characterized in that: The sliding mode control method comprises the following steps: Step 4.1: Sliding surface design: Sliding surface design is performed based on the motor dynamics model. First, the state quantities x1 and x2 are set: Among them, v ref is the target speed signal, v is the actual speed signal, is the state quantity x1 after derivation; Combining formula (6) with formula (5), the system state space equation is established: Among them, the control input is u=i(t)′, and the mass sum of the load and the motor primary is M=m+m0; Design the sliding surface function according to the system state space equation: s=cx1+x2 (8) Among them, the design parameter c>0; By differentiating formula (8), we can get the sliding surface derivative function: Step 4.2: Exponential approach rate design: According to the sliding surface function and the system state space equation, design the exponential approach rate used in the sliding mode control method: Among them, the design parameters ε>0, q>0; sgn() is the sign function; Step 4.3: Sliding mode controller design: First, substitute the exponential approach rate formula (10) into the sliding surface derivative function formula (9) to establish a preliminary sliding mode controller: Substitute the control input u=i(t)′ into formula (11) to obtain the final sliding mode controller: Among them, i is the current control variable.

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