| Pneumatic transmission equipment has become one of the important industrial equipment in modern society because of its features of simple component structure,anti-environmental pollution,strong anti-interference,low cost,high power volume ratio and convenient centralized gas supply.As a typical application of pneumatic transmission equipment,electro-pneumatic proportional position control system has been widely used in packaging,machinery,printing,electronics and other industries.However,due to the influence of gas compressibility,cavity and load variation,the electro-pneumatic proportional position control system is a kind of nonlinear and time-varying system in nature,which makes it difficult to control the electro-pneumatic proportional position control system.Gain PID control is usually prescribed,but it is difficult to meet the positioning control accuracy requirements of modern industrial equipment because the controller parameters are difficult to set and cannot adapt to the system parameter changes.In order to solve the electrical and pneumatic proportional position control system of PID control precision problem,this thesis designs a load compensation electrical and pneumatic proportional position control system of fuzzy neural network（FNN）control structure and algorithm,on the basis of the conventional PID control is a combination of fuzzy control of humanoid thought and the adaptability of neural network,It solves the problem that conventional PID control is difficult to adapt to the dynamic change of nonlinear and time-varying system because of fixed parameters,and the effectiveness of the control algorithm is verified by simulation and experiment.The main research work of this thesis is as follows:（1）The nonlinear and time-varying factors of the system are analyzed,the mathematical model of the electric-gas proportional position control system is established,and the parameterized mathematical model of the experimental platform is established according to the experimental equipment parameters,and its stability is verified.（2）The limitation of the conventional PID control strategy is analyzed,and the FNN control strategy is proposed,which takes setting displacement and cylinder pressure as input and PID controller output as learning signal,and a control structure and algorithm of the electro-pneumatic proportional position control system FNN based on load compensation is designed.（3）The mathematical model of electro-pneumatic proportional directional control valve control cylinder（valve-controlled cylinder）is established by AMESim.The control system is established by Simulink and the control algorithm is written by S function.The simulation verifies that the FNN structure and algorithm can effectively reduce the error of conventional PID control.（4）Build the experimental platform of electro-pneumatic proportional position control system,write the Lab VIEW measurement and control program,and experimentally study the trajectory tracking characteristics of FNN control and conventional PID control under the interference of cylinder velocity,load force and load cavity changes when sinusoidal wave,triangular wave,random waveform and step signal are input.Experimental results show that the FNN structure and algorithm can effectively compensate the error caused by the variation of load cavity and load force. |
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