Research On Characteristic Modeling And Control Algorithm Of Multi-motor Servo System With Nonlinear Links

In the modern military field,the tracking target of weapon servo system has the characteristics of fast moving speed and strong maneuverability.In order to hit the target in time and accurately,the weapon servo system must have the ability of fast response and high precision tracking.Aiming at the requirements of high power,high precision,fast response and strong robustness of weapon servo system,this paper studies a kind of multi-motor servo system with non-linear links.Based on the theory of characteristic modeling,the characteristic model of the multi-motor servo system is established,and the adaptive position control algorithm and compensation algorithm of non-linear link are designed.The specific contents are as follows:For multi-motor servo system with non-linear links,the dynamic model of four-motor servo system under ideal conditions is established.Then,based on the analysis of backlash and friction nonlinearity,the dynamic model of four-motor servo system with backlash and friction nonlinearity is established.Based on the environment of MATLAB/Simulink,a fourmotor servo system model with non-linear links is built,and the validity of the model is verified by simulation.Based on the theory of characteristic modeling,the characteristic model of the system is established.In order to study the effect of different identification algorithms on the identification of characteristic parameters,the recursive least squares method with forgetting factor and gradient descent method are used to identify the parameters of the characteristic model.The simulation results show that the recursive least squares method with forgetting factor has better identification effect.Aiming at the problem of measurement noise in the process of characteristic parameter identification,Kalman filtering algorithm based on characteristic model is designed,and the effectiveness of the algorithm is verified by simulation.Aiming at the high precision tracking problem of multi-motor servo system with nonlinear links,an adaptive discrete sliding mode controller based on characteristic model is designed.The stability of the system is proved.The simulation results show that the proposed control algorithm can effectively track three typical signals,step,slope and sine.In order to improve the tracking accuracy of the system for sine signals,based on characteristic model,a composite controller of feedforward control and discrete second-order sliding mode is designed.The stability of the system is proved.The simulation results show that the tracking accuracy of the system for sine signals can be further improved by the proposed control algorithm.To solve the problem of friction nonlinearity in multi-motor servo system,particle swarm optimization(PSO)is used to identify the parameters of the stribeck friction model of the system,and a compensation strategy based on stribeck friction model is designed.The simulation results show that the proposed algorithm can effectively compensate the friction nonlinearity.In order to verify the validity of position control strategy of multi-motor servo system,the control algorithm designed in this paper is tested on the experimental platform.The experimental results show that the control algorithm designed in this paper has fast response speed and high tracking accuracy.