Design And Implementation For The Test Platform Of PLC Based Linear Active Disturbance Rejection Control Approach

The traditional PID control approach,which plays a predominant role in the industry control field,is limited in the improvement of its performance,and becomes gradually unable to meet the high control requirements.Therefore,based on active disturbance rejection control(ADRC)approach,the linear active disturbance rejection controller(LADRC)appeared and it was invented to simplify the parameters.Since PLC is the most prevalent controller applied in the auxiliary control system of power plant,to explore the fundamental principles and the implementations of LADRC approach in control devices such as PLC is significant and meaningful for the advance of the application of it in real control process.Thus,considering some factors,such as the unreliability of application in the control system for power plant with the advanced control apporach,as well as the economic problem,a set of test platform of PLC based LADRC approach is designed and constructed in the laboratory.Then on the strength of applying the intelligent optimization algorithm to accomplish the identification of the model of the controlled object,the parameters of PI controller and LADRC controller are optimized through the computer simulation.Furthermore,with the optimized parameters of controller,the performance of LADRC apporach implemented in PLC is compared with PI control in the real control porcess,and the theoretical guidance for the further practical application can be provided with the test platform that was bulit in this thesis.This thesis conducted an experiment aimed at the DELTA servo driver system and based on the PLC of Siemens —— S7-1200.Firstly,the form of hardware of the test platform was introduced and the circuit design is completed.Then in TIA V13,the program including the control logic,strategy and the monitor screen can be implemented with the help of STEP7 and Win CC respectively,and finally the open-loop control of the servo motor and the PID closed-loop control of speed were successfully accomplished.Then in MATLAB/Simulink,based on the particle swarm algorithm(PSO)and algebraic parameter identification approach,the offline identification of the controlled object —— servo driver system,can be conducted with the analysis of the historical data of actual speed that was gathered before.Afterwards,PSO and bacterial foraging algorithm(BFO)approaches were used respectively to achieve the parameters optimization of the PI controller for the speed control of servo motor,and the controller parameters obtained through simulating optimization was verified in the practical experiment platform.At the same time,the discrete time LADRC approach was implemented in simulation based on the identified controlled model with the parameters optimized by the above two approaches.Furthermore,the discrete time LADRC approach can be designed and implemented through the form of ladder diagram language(LAD)in PLC,and the parameters of the simulating setting was experimentally verified in the actual platform.The effectiveness and robustness of the discrete time LADRC approach in PLC can be successfully proved by the experimental results.Finally,the arbitrary bumpless switching is designed and implemented in the PLC,including three modes: manual,PID control,and LADRC approach modes,and then the feasibility and the effectiveness of the referred algorithm is validated via the extensive experimental results.