Double Closed Loop Control Modeling And Simulation Analysis For Flutter Signal Adaptive Of Proportional Directional Valve

Compared with the servo valve,the proportional valve has the advantages of low cost,high anti-pollution ability and the like.At present,the proportional valve is developing towards large flow,high frequency response,and intelligence.However,due to the effect of frictional nonlinearity,the proportional valve is operated at low speeds,and the phenomenon of poor fretting characteristics,hysteresis,and dead zone often occurs,which affects the dynamic performance of the proportional valve under normal operation.For this reason,this paper deduces the dynamics equation of the proportional directional valve spool,sets up the mathematical model of the force of the valve core,and uses AMESim software to simulate.The result shows that: As the valve opening increases,the amplitude value of displacement tremor appears attenuation,and presents a nonlinear change.In order to further investigate the main factors affecting the attenuation of the amplitude of the flutter,the force condition of the spool is analyzed.The results show that the friction is the main factor that causes the attenuation of the amplitude of the flutter.In order to improve the attenuation of the flutter amplitude of the proportional directional valve,a double closed-loop control system is proposed.This system is based on the original displacement control closed-loop,and superimposes a flutter amplitude control closed-loop.The specific realization is that the displacement amount and the flutter amount separated from the valve core displacement signal are respectively different from the respective set values to perform PID control,and then the two control amounts are superimposed and returned to the system.In order to keep the amplitude of vibration of the proportional directional valve spool consistent during the full stroke motion,two self-adaptive PID control of the amplitude of the quiver are proposed and applied to the co-simulation of the force model of the valve core.The results show that: Displacement PID control on the closedloop,superimposed trembling amplitude adaptive PID control closed-loop,can well solve the valve spool full-stoke tremble amplitude attenuation phenomenon.