| With the increasingly application of electric actuator,the industrial control demands on the control performance,control accuracy and anti-interference performance of electric actuator.In order to deal with the slow response and poor robustness of traditional PID control systems,model predictive control is applied to the control system of electric actuators with multiobjective,rolling optimization,multi-constraint,and nonlinearity.The main research work is as follows:According to the working principle and characteristic index requirements of electric actuators,model predictive current control is applied to the control system of electric actuators.Three closed-loop control system is designed as the overall scheme,and the current loop of the inner loop is replaced by MPC controller.The model of electric actuator is built,including asynchronous motors,sensors,valves,transmission systems etc.And analyze the valve links from three aspects of flow characteristics,the relationship between opening and flow pressure difference,and mechanical analysis.According to the principle of finite set model predictive control,the predictive model,controller and objective function of the inverter model predictive control are designed.Then conduct simulation analysis,correct the delay of a sampling period of the current command,and use the advantages of multi-step prediction optimize control delay.Provide a theoretical basis for the research on model predictive current control of electric actuator system.The discrete-time state-space model predictive controller of electric actuator has been established and cost function is built.Besides,model,analyze and design the velocity loop and the position loop respectively.The simulation results show that compared with traditional PID control,the system adopting model predictive control has better dynamic response characteristics and stronger anti-interference ability.The control system is still in the case of motor stator and rotor resistance mismatch of ±20% and mutual inductance mismatch of-20%.It can work normally,and can cope with the normal operation of large and small torque valves,and the overall control effect is better.Based on the SAF-XE167-72F80 L master MCU of Infineon,the program of control panel,upper computer and display screen is designed to realize human-computer interaction of the actuator.The overall experimental platform of the electric actuator is built,and the experimental results are consistent with the simulation analysis results,which verifies the effectiveness and feasibility of the proposed scheme. |
