Fractional Order Control Study Of Cold Rolling APC System

Hydraulic automatic position control system is the key control and execution part of the cold rolling plate thickness control system,which directly affects the forming quality of cold rolled strip,so it is very important to study how to improve the performance of APC system.The traditional PID controller has a few adjustable parameters,and the parameter setting depends on the artificial experience.As a result of the combination of fractional calculus and PID controller,the differential order?and integral order ? make the fractional order PID controller has more freedom.In order to solve the problem of parameter tuning of fractional order PID,we uses intelligent algorithm to tune the fractional order PID parameters,which can avoid the tedious process of manual adjustment.Moreover,this paper conduct in-depth simulation research in this field and the main contents include the following aspects:The working principle of servo amplifier,servo valve,hydraulic cylinder and sensor in APC system is analyzed,and then the nonlinear and linear mathematical model of APC system is established by means of mechanism modeling.PID controller is replaced by fractional order PID and the indirect and direct realization of fractional calculus are discussed respectively,which is prepared for the subsequent chapters based on the intelligent algorithm of fractional order PID parameter customization.For improving the rapidity and stability of APC system,the objective function is set for the APC system in time domain and frequency domain.And the multi-objective particle swarm optimization algorithm is improved to promote the convergence speed and accuracy of the algorithm.The improved multi-objective particle swarm optimization algorithm is used to optimize the fractional order PID parameters and improve the time domain response and robustness of the APC system.In order to solve the parameter optimization problem of fractional order PID online,the RBF neural network is used to adjust the controller parameters according to the input and output.At the same time,through a special coding method,the particle swarm optimization algorithm with 2 mutation mechanism is used to optimize the initial parameters and topology of the network,which can improve on line control precision and anti-interference ability of APC control system...