Direct drive motor sliding mode control method and device

Abstract

The application discloses a direct drive motor sliding mode control method and device, and particularly relates to the technical field of direct drive motor control. In the process of the sliding mode control system sending an execution instruction of a current action to control the direct drive motor to drive an end effector to operate, operation data of the direct drive motor is acquired to obtain a fault judgment value of the direct drive motor, and the fault judgment value of the direct drive motor is compared with a preset fault judgment value threshold to judge whether the direct drive motor has a fault. If the direct drive motor has no fault, the parameters of a PID controller are optimized when the sliding mode control system sends an execution instruction of a next action, and the delay between the sliding mode control system and the direct drive motor is controlled. In this way, whether the delay between the sliding mode control system and the direct drive motor can be reduced by optimizing the parameters of the PID controller when judging whether the direct drive motor has a fault can be known, blind optimization cost is reduced, and the fault of the direct drive motor is not further deepened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of direct drive motor control, and particularly relates to a direct drive motor sliding mode control method and device. BACKGROUND

[0002] The direct drive motor sliding mode control system is a control system for realizing the control of the motion of the direct drive motor by using the sliding mode control strategy. The direct drive motor is an electric motor that directly converts electric energy into mechanical energy. It has the characteristics of simple structure, fast response speed and high precision, and is therefore widely used in some devices that require fast response and high-precision position control, such as industrial robots. By installing a direct drive motor inside the industrial robot, the joints of the robot are driven, so that the end effector of the robot can perform accurate motion in space. The direct drive motor sliding mode control system drives the direct drive motor to move by designing a sliding mode control strategy, so as to drive the industrial robot to perform fast response and high-precision position control.

[0003] When controlling the motion of the direct drive motor, the sliding mode control system may have a delay when controlling the direct drive motor. The traditional method usually directly uses an optimization algorithm to reduce the delay between the sliding mode control system and the direct drive motor. For example, by adjusting the parameters of the PID controller, the delay between the sliding mode control system and the direct drive motor is reduced. However, in some cases, such as when the direct drive motor fails, no matter how the parameters of the PID controller are optimized, the delay between the sliding mode control system and the direct drive motor will not be reduced. Blind optimization not only increases the calculation cost, but also may further deepen the failure of the direct drive motor. SUMMARY

[0004] The purpose of the present application is to solve the problem of blind optimization which not only increases the calculation cost, but also may further deepen the failure of the direct drive motor. A direct drive motor sliding mode control method and device are proposed.

[0005] In the first aspect of the present application, a direct drive motor sliding mode control method is first proposed, which comprises:

[0006] In the process of the sliding mode control system issuing an execution instruction of the current action to control the direct drive motor to drive the end effector to perform an action operation, the running data of the direct drive motor is obtained, and a failure judgment value of the direct drive motor is obtained according to the running data. The running data includes the resistance increase degree and the variable coupling increase degree of the direct drive motor.

[0007] The failure judgment value of the direct drive motor is compared with a preset failure judgment value threshold to determine whether the direct drive motor has a failure.

[0008] If the direct drive motor fault is not a fault, the parameter of the PID controller is optimized when the sliding mode control system sends the next action execution instruction, and the delay between the sliding mode control system and the direct drive motor is controlled.

[0009] Optionally, the step of calculating the resistance increase degree comprises:

[0010] After the direct drive motor receives the execution instruction of the current action sent by the sliding mode control system, the preset average resistance of the direct drive motor during the execution of the current action is taken as the initial resistance.

[0011] The actual resistance of the direct drive motor during the execution of the current action by the end effector is obtained, and the average value thereof is calculated to obtain a measured resistance, which is filtered to obtain a final resistance.

[0012] The difference between the final resistance and the initial resistance value is calculated, and the difference is divided by the initial resistance value to obtain a resistance increase value.

[0013] Optionally, the variable coupling increase degree comprises:

[0014] For two coupled variables of the direct drive motor during the execution of the current action by the end effector, the two coupled variables of the same timestamp are taken as an independent correlation set;

[0015] The independent correlation set of the direct drive motor at each time during the execution of the current action by the end effector is obtained to obtain a time-ordered independent correlation set sequence.

[0016] The coupling correlation value between the two coupled variables of the direct drive motor is calculated according to the independent correlation set sequence, and the formula is: In the formula, is the coupling correlation value, and are the numbers of the two coupled variables in the i th state parameter independent correlation set in the independent correlation set sequence; and are the average values of the two coupled variables in the independent correlation set sequence;

[0017] The coupling correlation value is subtracted from the preset maximum coupling correlation value of the two coupled variables of the direct drive motor to obtain a coupling correlation value excess degree, and the coupling correlation value excess degree is divided by the preset maximum coupling correlation value to obtain the coupling increase degree of the direct drive motor.

[0018] Optionally, the step of obtaining the fault judgment value of the direct drive motor according to the operation data comprises:

[0019] The operation data includes an increase degree of resistance of the direct-drive motor and an increase degree of variable coupling, and the increase degree of resistance and the increase degree of variable coupling are added to obtain a fault judgment value of the direct-drive motor;

[0020] The fault judgment value of the direct-drive motor is compared with a preset fault judgment value threshold, if the fault judgment value is not less than the preset fault judgment value threshold, it indicates that the direct-drive motor is faulty, the sliding mode control system cannot control the direct-drive motor to respond in real time, and a fault warning is issued;

[0021] If the fault judgment value is less than the preset fault judgment value threshold, it indicates that the direct-drive motor is not faulty, the sliding mode control system can control the direct-drive motor to respond in real time, and delay optimization is performed.

[0022] Optionally, the parameters of the PID controller are optimized, and the step of controlling the delay between the sliding mode control system and the direct-drive motor is as follows:

[0023] The actual delay time between the sliding mode control system and the direct-drive motor is subtracted by a preset longest delay time threshold to obtain a delay error value, and the delay error value is minimized as an optimization target function;

[0024] The particle swarm is initialized, and the initial position of each particle is the initial value of the PID controller Kp, Ki and Kd;

[0025] The delay error value of each particle is calculated as an evaluation standard of the target function;

[0026] The speed and position of the particle are updated, and the individual optimal solution and the global optimal solution are updated according to the target function value;

[0027] When the stop condition is met, the optimal PID parameters are output, and the delay between the sliding mode control system and the direct-drive motor is optimized.

[0028] In the second aspect of the embodiment of the present application, a sliding mode control device for a direct-drive motor is provided, and the device comprises:

[0029] A fault judgment value module: in the process that the sliding mode control system issues an execution instruction of a current action to control the direct-drive motor to drive an end effector to perform an action operation, operation data of the direct-drive motor is obtained, and a fault judgment value of the direct-drive motor is obtained according to the operation data; the operation data includes an increase degree of resistance of the direct-drive motor and an increase degree of variable coupling;

[0030] A judgment module: the fault judgment value of the direct-drive motor is compared with a preset fault judgment value threshold, and whether the direct-drive motor is faulty is judged;

[0031] The optimization control module: if the direct drive motor is not in failure, the parameter of the PID controller is optimized while the next action execution instruction is sent by the sliding mode control system, and the delay between the sliding mode control system and the direct drive motor is controlled.

[0032] Optionally, the failure judgment value module comprises:

[0033] The initial resistance module: after the direct drive motor receives the execution instruction of the current action sent by the sliding mode control system, the preset average resistance of the direct drive motor in the execution process of the current action is taken as the initial resistance.

[0034] The final resistance module: the actual resistance of the direct drive motor in the execution process of the current action of the end effector is obtained, and the average value thereof is calculated to obtain a measured resistance, and the measured resistance is filtered to obtain a final resistance.

[0035] The resistance increase degree module: the difference between the final resistance and the initial resistance value is calculated, and the difference is divided by the initial resistance value to obtain the resistance increase degree.

[0036] Optionally, the failure judgment value module further comprises:

[0037] The independent correlation set module: for two coupled variables of the direct drive motor in the execution process of the current action of the end effector, the two coupled variables of the same time stamp are taken as an independent correlation set.

[0038] The sequence module: the independent correlation set of each time of the direct drive motor in the execution process of the current action of the end effector is obtained to obtain a time sequence-based independent correlation set sequence.

[0039] The coupling correlation value module: the coupling correlation value between the two coupled variables of the direct drive motor is calculated according to the independent correlation set sequence, and the formula is: , wherein, is the coupling correlation value, and are the numbers of the two coupled variables in the i th state parameter independent correlation set in the independent correlation set sequence; and are the average values of the two coupled variables in the independent correlation set sequence;

[0040] The coupling increase degree module: the coupling correlation value is subtracted from the preset maximum coupling correlation value of the two coupled variables of the direct drive motor to obtain a coupling correlation value excess degree, and the coupling correlation value excess degree is divided by the preset maximum coupling correlation value to obtain the coupling increase degree of the direct drive motor.

[0041] Optionally, the fault judgment value module further comprises a fault judgment value module, and the judgment module comprises a first judgment module and a second judgment module, wherein:

[0042] The fault judgment value module is used for adding the resistance increase degree and the variable coupling increase degree to obtain a fault judgment value of the direct drive motor according to the operation data including the resistance increase degree and the variable coupling increase degree of the direct drive motor;

[0043] The first judgment module is used for comparing the fault judgment value of the direct drive motor with a preset fault judgment value threshold value, and if the fault judgment value is not less than the preset fault judgment value threshold value, it indicates that the direct drive motor is faulty, the sliding mode control system cannot control the direct drive motor to respond in real time, and a fault warning is issued;

[0044] The second judgment module is used for comparing the fault judgment value with the preset fault judgment value threshold value, and if the fault judgment value is less than the preset fault judgment value threshold value, it indicates that the direct drive motor is not faulty, the sliding mode control system can control the direct drive motor to respond in real time, and delay optimization is performed.

[0045] Optionally, the optimization control module comprises:

[0046] The target function module is used for subtracting a preset longest delay time threshold value from an actual delay time between the sliding mode control system and the direct drive motor to obtain a delay error value, and the delay error value is used as a target function for minimization;

[0047] The initialization module is used for initializing a particle swarm, and an initial position of each particle is an initial value of a PID controller Kp, Ki and Kd;

[0048] The calculation module is used for calculating the delay error value of each particle as an evaluation standard of the target function;

[0049] The update module is used for updating the speed and position of the particle, and updating an individual optimal solution and a global optimal solution according to the target function value;

[0050] The optimization control module is used for outputting an optimal PID parameter when a stop condition is met, and optimizing the delay between the sliding mode control system and the direct drive motor.

[0051] The present application has the following beneficial effects:

[0052] The application provides a direct-drive motor sliding mode control method and device, in the process that the current action execution instruction of the sliding mode control system controls the direct-drive motor to drive the end effector to perform action operation, the running data of the direct-drive motor is acquired to obtain the fault judgment value of the direct-drive motor, and the fault judgment value of the direct-drive motor is compared with a preset fault judgment value threshold to judge whether the direct-drive motor has a fault; if the direct-drive motor has no fault, the parameters of the PID controller are optimized when the next action execution instruction of the sliding mode control system is issued, and the delay between the sliding mode control system and the direct-drive motor is controlled; in this way, whether the direct-drive motor has a fault can be judged, whether the delay between the sliding mode control system and the direct-drive motor can be reduced by optimizing the parameters of the PID controller, blind optimization cost is reduced, and the fault of the direct-drive motor is not further deepened. BRIEF DESCRIPTION OF DRAWINGS

[0053] The application will be further described below in combination with the drawings.

[0054] Figure 1 A flowchart of a direct-drive motor sliding mode control method provided for the embodiment of the application;

[0055] Figure 2 A framework diagram of a direct-drive motor sliding mode control device provided for the embodiment of the application. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the application will be clearly and completely described below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0057] Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0058] The embodiment of the application provides a direct-drive motor sliding mode control method. Referring to Figure 1 , Figure 1 A flowchart of a direct-drive motor sliding mode control method provided for the embodiment of the application. The method comprises the following steps:

[0059] In the process that the current action execution instruction of the sliding mode control system controls the direct-drive motor to drive the end effector to perform action operation, the running data of the direct-drive motor is acquired to obtain the fault judgment value of the direct-drive motor; the running data comprises the resistance increase degree and the variable coupling increase degree of the direct-drive motor;

[0060] The fault judgment value of the direct drive motor is compared with a preset fault judgment value threshold to determine whether the direct drive motor has a fault.

[0061] If the direct drive motor has no fault, the parameters of the PID controller are optimized when the sliding mode control system issues an execution instruction of a next action, and the delay between the sliding mode control system and the direct drive motor is controlled.

[0062] Based on the direct drive motor sliding mode control method provided in the embodiment, when it is determined whether the direct drive motor has a fault, it can be determined whether the delay between the sliding mode control system and the direct drive motor can be reduced by optimizing the parameters of the PID controller, the blind optimization cost is reduced, and the fault of the direct drive motor is not further deepened.

[0063] In one embodiment, the calculation step of the resistance increase degree is:

[0064] After the direct drive motor receives an execution instruction of a current action issued by the sliding mode control system, a preset average resistance of the direct drive motor in the execution of the current action is used as an initial resistance.

[0065] The actual resistance of the direct drive motor in the execution of the current action of the end effector is obtained, and an average value thereof is calculated to obtain a measured resistance, which is filtered to obtain a final resistance.

[0066] The difference between the final resistance and the initial resistance value is calculated, and the difference is divided by the initial resistance value to obtain a resistance increase value.

[0067] It should be noted that the actual resistance of the direct drive motor in the execution of the current action of the end effector can be obtained by calculating the corresponding resistance through the voltage sensor and the current sensor in the direct drive motor, and the specific process will not be described here.

[0068] It should be noted that the measured resistance can be filtered by Kalman filtering, moving average filtering, etc., and the specific process will not be described here. By filtering the measured resistance, noise and measurement error can be effectively reduced, more reliable and accurate resistance measurement results can be provided, and the state of the electrode can be more accurately determined.

[0069] It should be noted that the increase in resistance increase generally means that there is a large loss inside the direct drive motor, such as winding insulation aging or mechanical wear and tear, which will cause the efficiency of the motor to decrease and the heat to increase. With the increase of resistance, the dynamic performance and response speed of the motor are affected, resulting in the increase of the lag and delay of the control signal transmission. Although the optimization of the parameters of the PID controller can reduce the delay between the control system and the motor to some extent, the fundamental reason for this delay is the change of the physical loss and electrical characteristics inside the motor, and the PID optimization mainly adjusts the control strategy and cannot change the physical performance of the motor itself. Therefore, no matter how the PID control is optimized, the delay problem caused by the internal failure of the motor still exists and cannot be effectively solved.

[0070] In one embodiment, the variable coupling increase degree comprises:

[0071] For two coupled variables of the direct drive motor in the process of the end effector performing the current action, two coupled variables of the same timestamp are taken as an independent correlation set;

[0072] Obtain the independent correlation set of the direct drive motor at each time in the process of the end effector performing the current action, and obtain the time-sequential independent correlation set sequence;

[0073] According to the independent correlation set sequence, the coupling correlation value between the two coupled variables of the direct drive motor is calculated, and the formula is: , wherein, is the coupling correlation value, and are the numbers of the two coupled variables in the i th state parameter independent correlation set in the independent correlation set sequence; and are the average values of the two coupled variables in the independent correlation set sequence;

[0074] Subtract the preset maximum coupling correlation value of the two coupled variables of the direct drive motor from the coupling correlation value to obtain the coupling correlation value excess degree, and divide the coupling correlation value excess degree by the preset maximum coupling correlation value to obtain the coupling increase degree of the direct drive motor;

[0075] It should be noted that the two coupled variables can be any two related state parameters in the direct drive motor; for example, the speed and torque, current and voltage of the direct drive motor, which are set by professionals and are not limited in detail; and the values of the two coupled variables can be obtained by the corresponding sensors inside the direct drive motor, which is not described in detail.

[0076] For example, in terms of speed and torque, under normal circumstances, the coupling between speed and torque is weak, and they are relatively independent of each other. Speed is mainly controlled by the input signal of the motor, while torque is more dependent on load changes and the physical characteristics of the motor. When the direct drive motor is in good condition, the changes in speed and torque will not interfere with each other. However, once the coupling increase degree increases, the relationship between speed and torque becomes more close, in which case the changes in speed and torque will become more synchronized, causing the motor to be unable to adjust its output in time, increasing the risk of failure, making it difficult for the sliding mode control system to control the direct drive motor to respond in real time, and thus affecting the accuracy of the action of the end effector and the stability of the motion control.

[0077] It should be noted that the greater the coupling increase degree, the greater the degree of coupling between variables in the system, and the greater the likelihood of direct drive motor failure. Therefore, no matter how the parameters of the optimized PID controller are optimized, the delay between the sliding mode control system and the direct drive motor will not be reduced, because the greater the coupling increase degree, the greater the degree of coupling between the two related variables inside the direct drive motor, which is usually caused by the wear or failure of some components inside the motor. For example, the coupling between speed and torque, current and voltage, may reflect mechanical or electrical problems inside the motor, such as bearing wear, unstable electrical connections, or winding damage. As the coupling increases, the dynamic response of the motor becomes more complex, and the control system must be more precise to maintain stability. Although optimizing the parameters of the PID controller helps improve control accuracy, these optimizations are mainly aimed at the control strategy of the system and cannot directly change the internal failure or performance degradation of the motor. Therefore, the internal failure and performance degradation of the motor caused by the coupling increase will still cause the existence of control delay, and the PID optimization cannot eliminate these fundamental problems.

[0078] In one embodiment, the step of obtaining a fault judgment value of the direct drive motor according to the operating data is:

[0079] The operating data includes the resistance increase degree and the variable coupling increase degree of the direct drive motor, and the resistance increase degree and the variable coupling increase degree are added to obtain the fault judgment value of the direct drive motor;

[0080] The fault judgment value of the direct drive motor is compared with a preset fault judgment value threshold, and if the fault judgment value is not less than the preset fault judgment value threshold, it indicates that the direct drive motor is faulty, the sliding mode control system cannot control the direct drive motor to respond in real time, and a failure warning is issued;

[0081] If the fault judgment value is less than the preset fault judgment value threshold, it indicates that the direct drive motor is not faulty, the sliding mode control system can control the direct drive motor to respond in real time, and delay optimization is performed.

[0082] It should be noted that the preset fault judgment value threshold is set by a professional according to the actual situation, and the specific implementation is not limited and described.

[0083] In one implementation, by the above method, when it is determined that the direct drive motor has a fault, it can be determined whether the delay between the sliding mode control system and the direct drive motor can be reduced by optimizing the parameters of the PID controller, the cost of blind optimization is reduced, and the fault of the direct drive motor is not further deepened.

[0084] In one embodiment, if the direct drive motor fault has no fault, when the sliding mode control system issues an execution instruction for the next action, the parameters of the PID controller are optimized, and the step of controlling the delay between the sliding mode control system and the direct drive motor is:

[0085] The actual delay time between the sliding mode control system and the direct drive motor is subtracted from the preset longest delay time threshold to obtain a delay error value; and the delay error value is minimized as an optimization target function;

[0086] Initialize the particle swarm, and the initial position of each particle is the initial value of the PID controller Kp, Ki and Kd;

[0087] Calculate the delay error value of each particle as the evaluation standard of the target function;

[0088] Update the speed and position of the particle, and update the individual optimal solution and the global optimal solution according to the target function value.

[0089] When the stop condition is met, the optimal PID parameters are output, and the delay between the sliding mode control system and the direct drive motor is optimized.

[0090] It is necessary to point out that in the absence of direct drive motor failure, the parameters of the PID controller are optimized by particle swarm optimization (PSO), the purpose is to reduce the delay between the sliding mode control system and the direct drive motor. First of all, we need to measure the actual delay time between the sliding mode control system and the direct drive motor in the system, and compare it with the preset maximum delay time threshold, and calculate the delay error value. This error value is used as the optimization objective function, and the task of PSO is to optimize the parameters of the PID controller by minimizing the delay error value to ensure that the system response time is minimized, thereby reducing the delay. Then, initialize the particle swarm, each particle represents a combination of PID controller parameters (Kp, Ki, Kd). For example, assume that the initial position of particle 1 is (Kp=20, Ki=0.5, Kd=1), and the initial position of particle 2 is (Kp=30, Ki=0.7, Kd=1.5), the goal of each particle is to optimize the delay error. Next, we calculate the delay error value of each particle as the evaluation criterion of the objective function to measure the goodness of each parameter combination. The particle swarm updates the speed and position of each particle to find the optimal PID parameters. Each particle updates its individual optimal solution (pbest) and global optimal solution (gbest) according to its objective function value (delay error). The particles continuously iterate, update their positions and approach the optimal solution. When the predetermined stopping condition (such as the target error is less than the threshold or the maximum number of iterations is reached) is reached, the particle swarm optimization algorithm stops, and the optimal PID parameters output will be used to control the system. In this way, PSO can effectively optimize the parameters of the PID controller without motor failure, thereby reducing the delay between the sliding mode control system and the direct drive motor, improving the response speed and control accuracy of the system. For example, if the optimal PID parameters found by the particle swarm are Kp=25, Ki=0.6, Kd=1.2, the control system will apply these parameters to reduce the delay of the system and ensure fast and accurate motion control.

[0091] In an implementation, by adjusting the parameters of the PID controller in the above manner, the delay between the sliding mode control system and the direct drive motor is reduced, avoiding blind increase in computational cost and further deepening the failure of the direct drive motor.

[0092] Based on the same inventive concept, the embodiments of the present application also provide a direct drive motor sliding mode control device. Referring to Figure 2 , Figure 2 A structural schematic diagram of a direct drive motor sliding mode control device provided by the embodiments of the present application, the system comprises:

[0093] The fault judgment value module obtains running data of the direct-drive motor during the process that the sliding mode control system sends an execution instruction of a current action to control the direct-drive motor to drive the end effector to operate, and obtains a fault judgment value of the direct-drive motor according to the running data, wherein the running data includes an increase degree of resistance and an increase degree of variable coupling of the direct-drive motor.

[0094] The judgment module compares the fault judgment value of the direct-drive motor with a preset fault judgment value threshold, and judges whether the direct-drive motor has a fault.

[0095] The optimization control module controls the delay between the sliding mode control system and the direct-drive motor by optimizing parameters of the PID controller when the sliding mode control system sends an execution instruction of a next action, if the direct-drive motor has no fault.

[0096] The direct-drive motor sliding mode control device provided by the embodiment of the application can judge whether the direct-drive motor has a fault, whether the delay between the sliding mode control system and the direct-drive motor can be reduced by optimizing parameters of the PID controller, reduce blind optimization cost, and further reduce the fault of the direct-drive motor.

[0097] In one embodiment, the fault judgment value module comprises:

[0098] The initial resistance module regards a preset average resistance of the direct-drive motor during the process of executing the current action as an initial resistance after the direct-drive motor receives the execution instruction of the current action sent by the sliding mode control system.

[0099] The final resistance module obtains an actual resistance of the direct-drive motor during the process of executing the current action by the end effector, calculates an average value of the actual resistance to obtain a measured resistance, filters the measured resistance to obtain a final resistance.

[0100] The resistance increase degree module calculates a difference between the final resistance and the initial resistance, and divides the difference by the initial resistance to obtain the resistance increase degree.

[0101] In one embodiment, the fault judgment value module further comprises:

[0102] The independent correlation set module regards two coupled variables of the direct-drive motor during the process of executing the current action by the end effector as an independent correlation set with the same time stamp.

[0103] The sequence module obtains an independent correlation set sequence based on time sequence by obtaining the independent correlation set of the direct-drive motor at each time during the process of executing the current action by the end effector.

[0104] The coupling correlation value module calculates a coupling correlation value between the two coupled variables of the direct-drive motor according to the independent correlation set sequence, and the formula is:

[0105] wherein, is a coupling correlation value, and are the numbers of two coupled variables in the independent correlation set of the i-th state parameter in the independent correlation set sequence, respectively; i and are the average values of the two coupled variables in the independent correlation set sequence, respectively;

[0106] The coupling increase degree module: subtracts the preset maximum coupling correlation value of the two coupled variables of the direct drive motor from the coupling correlation value to obtain a coupling correlation value excess degree, and divides the coupling correlation value excess degree by the preset maximum coupling correlation value to obtain the coupling increase degree of the direct drive motor.

[0107] In one embodiment, the fault judgment value module further comprises a fault judgment value module, and the judgment module comprises a first judgment module and a second judgment module, wherein:

[0108] The fault judgment value module: is used for adding the resistance increase degree and the variable coupling increase degree of the direct drive motor according to the operation data to obtain a fault judgment value of the direct drive motor;

[0109] The first judgment module: is used for comparing the fault judgment value of the direct drive motor with a preset fault judgment value threshold value, and if the fault judgment value is not less than the preset fault judgment value threshold value, it indicates that the direct drive motor is faulty, the sliding mode control system cannot control the real-time response of the direct drive motor, and a fault warning is issued;

[0110] The second judgment module: if the fault judgment value is less than the preset fault judgment value threshold value, it indicates that the direct drive motor is not faulty, the sliding mode control system can control the real-time response of the direct drive motor, and delay optimization is performed.

[0111] In one embodiment, the optimization control module comprises:

[0112] The target function module: subtracts a preset maximum delay time threshold value from the actual delay time between the sliding mode control system and the direct drive motor to obtain a delay error value; and the delay error value is used as an optimization target function to be minimized;

[0113] The initialization module: initializes the particle swarm, and the initial position of each particle is the initial value of the PID controller Kp, Ki and Kd;

[0114] The calculation module: calculates the delay error value of each particle as an evaluation standard of the target function;

[0115] The update module: updates the speed and position of the particles, and updates the individual optimal solution and the global optimal solution according to the target function value;​

[0116] Optimization control module: output optimal PID parameters when the stop condition is met, optimize the delay between the sliding mode control system and the direct drive motor.

[0117] The above describes one embodiment of the present application in detail, but the content is only the preferred embodiment of the present application, and cannot be artificially used to limit the implementation range of the present application. Any equivalent changes and improvements made within the scope of the present application should still belong to the patent coverage range of the present application.

Claims

1. A direct drive motor sliding mode control method, characterized in that, The method comprises the following steps: In the process of driving the end effector by the direct drive motor under the execution instruction of the current action issued by the sliding mode control system, operation data of the direct drive motor is acquired, and a fault judgment value of the direct drive motor is obtained according to the operation data; the operation data comprises an increase degree of resistance of the direct drive motor and an increase degree of variable coupling of the direct drive motor; The fault judgment value of the direct drive motor is compared with a preset fault judgment value threshold, and whether the direct drive motor has a fault is judged; If the direct drive motor has no fault, parameters of a PID controller are optimized when the execution instruction of the next action is issued by the sliding mode control system, and a delay between the sliding mode control system and the direct drive motor is controlled; The step of optimizing the parameters of the PID controller is that an actual delay time between the sliding mode control system and the direct drive motor is subtracted by a preset longest delay time threshold to obtain a delay error value; the delay error value is taken as an optimization target function to be minimized; and the parameters of the PID controller are optimized through a particle swarm algorithm.

2. The direct drive motor sliding mode control method of claim 1, wherein, The calculation step of the increase degree of resistance is that: After the direct drive motor receives the execution instruction of the current action issued by the sliding mode control system, a preset average resistance of the direct drive motor in the process of executing the current action is taken as an initial resistance; An actual resistance of the direct drive motor in the process of executing the current action by the end effector is acquired, an average value of the actual resistance is calculated to obtain a measured resistance, the measured resistance is filtered to obtain a final resistance, and a difference between the final resistance and the initial resistance value is calculated, and the difference is divided by the initial resistance value to obtain an increase value of the resistance. The increase degree of variable coupling comprises:

3. The direct drive motor sliding mode control method of claim 1, wherein For two coupled variables of the direct drive motor in the process of executing the current action by the end effector, the two coupled variables of the same time stamp are taken as an independent correlation set; An independent correlation set sequence based on time sequence is obtained by acquiring the independent correlation set of the direct drive motor at each time point in the process of executing the current action by the end effector; A coupling correlation value is subtracted by a preset maximum coupling correlation value of the two coupled variables of the direct drive motor to obtain a coupling correlation value excess degree, and the coupling correlation value excess degree is divided by the preset maximum coupling correlation value to obtain the increase degree of coupling of the direct drive motor. The coupling correlation value between two coupled variables of the direct-drive motor is calculated according to the independent correlation set sequence, and the formula is: , wherein, is the coupling correlation value, and are the numbers of two coupled variables in the i-th state parameter independent correlation set in the independent correlation set sequence, respectively; and are the average values of the two coupled variables in the independent correlation set sequence, respectively. The step of obtaining the fault judgment value of the direct drive motor according to the operation data is that:

4. The direct drive motor sliding mode control method of claim 1, wherein, The operation data comprises the increase degree of resistance of the direct drive motor and the increase degree of variable coupling of the direct drive motor, and the increase degree of resistance and the increase degree of variable coupling are added to obtain the fault judgment value of the direct drive motor; The fault judgment value of the direct drive motor is compared with a preset fault judgment value threshold, if the fault judgment value is not less than the preset fault judgment value threshold, it indicates that the direct drive motor has a fault, the sliding mode control system cannot control the direct drive motor to respond in real time, and a fault warning is issued; If the fault judgment value is less than the preset fault judgment value threshold, it indicates that the direct drive motor has no fault, and the sliding mode control system can control the direct drive motor to respond in real time and perform delay optimization. The step of optimizing the parameters of the PID controller and controlling the delay between the sliding mode control system and the direct drive motor is that:

5. The direct drive motor sliding mode control method of claim 1, wherein An actual delay time between the sliding mode control system and the direct drive motor is subtracted by a preset longest delay time threshold to obtain a delay error value; the delay error value is taken as an optimization target function to be minimized. ​ Initialize the particle swarm, and initial positions of each particle are initial values of PID controller Kp, Ki and Kd; Calculate delay error value of each particle as evaluation standard of target function; Update velocity and position of each particle, and update individual optimal solution and global optimal solution according to target function value; When stop condition is met, output optimal PID parameters, and optimize delay between sliding mode control system and direct drive motor.

6. A direct drive motor sliding mode control method apparatus, characterized by, The device comprises: A fault judgment value module: obtains running data of the direct drive motor in the process that the sliding mode control system sends an execution instruction of a current action to control the direct drive motor to drive the end effector to perform an action operation, and obtains a fault judgment value of the direct drive motor according to the running data; the running data comprises resistance increase degree and variable coupling increase degree of the direct drive motor; A judgment module: compares the fault judgment value of the direct drive motor with a preset fault judgment value threshold, and judges whether the direct drive motor has a fault; An optimization control module: if the direct drive motor has no fault, simultaneously optimizes parameters of a PID controller when the sliding mode control system sends an execution instruction of a next action, and controls delay between the sliding mode control system and the direct drive motor; The step of optimizing the parameters of the PID controller is: subtracting a preset longest delay time threshold from actual delay time between the sliding mode control system and the direct drive motor to obtain a delay error value; minimizing the delay error value as an optimization target function; and optimizing the parameters of the PID controller through a particle swarm algorithm.

7. The direct drive motor sliding mode control method device according to claim 6, wherein, The fault judgment value module comprises: An initial resistance module: taking a preset average resistance of the direct drive motor in the process of performing the current action as an initial resistance after the direct drive motor receives an execution instruction of the current action sent by the sliding mode control system; A final resistance module: obtaining an actual resistance of the direct drive motor in the process of performing the current action by the end effector, calculating an average value of the actual resistance to obtain a measured resistance, and filtering the measured resistance to obtain a final resistance; A resistance increase degree module: calculating a difference value between the final resistance and the initial resistance value, and dividing the difference value by the initial resistance value to obtain a resistance increase degree.

8. The direct drive motor sliding mode control method device of claim 6, wherein, The fault judgment value module further comprises: An independent correlation set module: taking two coupled variables of the direct drive motor at the same time stamp as an independent correlation set during the process that the end effector performs the current action; A sequence module: obtaining an independent correlation set sequence based on time sequence by obtaining the independent correlation set of the direct drive motor at each time point during the process that the end effector performs the current action; A coupling correlation value module: calculating a coupling correlation value between the two coupled variables of the direct drive motor according to the independent correlation set sequence, and the formula is: wherein is a coupling correlation value, and are the indices of the two coupled variables in the i-th state parameter independent correlation set, respectively; and are the average values of the two coupled variables, respectively. A coupling increase degree module: subtracting a preset maximum coupling correlation value of the two coupled variables of the direct drive motor from the coupling correlation value to obtain a coupling correlation value excess degree, and dividing the coupling correlation value excess degree by the preset maximum coupling correlation value to obtain a coupling increase degree of the direct drive motor.

9. The direct drive motor sliding mode control method device of claim 6, wherein, The fault judgment value module further comprises a fault judgment value module, and the judgment module comprises a first judgment module and a second judgment module, wherein: The fault judgment value module is configured to obtain a fault judgment value of the direct-drive motor by adding the resistance increase degree and the variable coupling increase degree according to the operation data including the resistance increase degree and the variable coupling increase degree of the direct-drive motor; The first judgment module is configured to compare the fault judgment value of the direct-drive motor with a preset fault judgment value threshold, and if the fault judgment value is not less than the preset fault judgment value threshold, it indicates that the direct-drive motor is faulty, the sliding mode control system cannot control the direct-drive motor to respond in real time, and a fault warning is issued; The second judgment module is configured to compare the fault judgment value with the preset fault judgment value threshold, and if the fault judgment value is less than the preset fault judgment value threshold, it indicates that the direct-drive motor is not faulty, the sliding mode control system can control the direct-drive motor to respond in real time, and delay optimization is performed.

10. The direct drive motor sliding mode control method device of claim 6, wherein, The optimization control module includes: The target function module is configured to subtract a preset longest delay time threshold from an actual delay time between the sliding mode control system and the direct-drive motor to obtain a delay error value, and to minimize the delay error value as an optimization target function; The initialization module is configured to initialize a particle swarm, and an initial position of each particle is an initial value of a PID controller Kp, Ki and Kd; The calculation module is configured to calculate a delay error value of each particle as an evaluation standard of the target function; The update module is configured to update a speed and a position of the particle, and to update an individual optimal solution and a global optimal solution according to the target function value; The optimization control module is configured to output an optimal PID parameter when a stop condition is met, and to optimize a delay between the sliding mode control system and the direct-drive motor.

Images