Fuzzy PID Control Of Feed Axis Of Linear Motor And Analysis Of Following Error

Ultra-precision machine tools require high-precision motion control to achieve ultraprecision machining,and linear motors are gradually applied to ultra-precision machine tools because they can directly output linear motion and facilitate the improvement of motion accuracy.In this paper,the linear motor feed axis is taken as the object,with the goal of improving its following performance,and its adaptive control algorithm is studied.The main research work includes:(1)The model parameters of the linear motor were obtained by identification of the least square method,and the mathematical model of the linear motor was established.The PID+feedforward controller is designed,the PID parameters are adjusted by the particle swarm optimization,and the feedforward parameters are determined based on the error compensation.The Sobol sensitivity analysis method is used to study the sensitivity of each control parameter of the PID+feedforward controller to the following error.(2)In order to improve the following performance of the linear motor,the fuzzy controller is combined with the PID controller,and the feedforward + fuzzy PID controller is designed to dynamically adjust the proportional,integral,and derivative parameters during the control process;The Sobol sensitivity analysis method is used to study the sensitivity of each control parameter of the feedforward + fuzzy PID controller to the following error.(3)A sub-fuzzy controller is designed to adjust the quantization factor of fuzzy PID online.In order to reduce the adverse effects of subjective factors on the control performance during the design of fuzzy rules and membership functions,the neural network is used to optimize the fuzzy rules and membership functions,and a feedforward + self-adjusting quantization factor fuzzy neural PID controller is established.(4)The simulation model of the above three control algorithms is established,the step signal is used as the input of the system,the load interference is added,and the simulation experiment is carried out.The results show that the feedforward + self-adjusting quantization factor fuzzy neural PID controller has better following performance and Immunity performance.