Research on control characteristic and compensation of water hydraulic proportional pressure relief valve

Abstract

For the purpose of improving control performance of water hydraulic proportional valve,the PDBV type water hydraulic proportional pressure relief valve of TIEFENBACH was investigated through structure analysis and experiment.The experimental results of static control performance show that the hysteresis and dead band are large under open-loop control due to friction,steady flow force and hysteresis of electromagnetic actuator,etc.As a result,the closed-loop control is unstable.Aiming at decrease of hysteresis and dead band,the sectional linear inverse model of valve hysteresis was built based on least-square linear regression.With the experimental results,the hysteresis and dead band are greatly decreased through feed-forward static compensation.However,large overshoot and great pressure impact are induced.For the reason that linear controllable range among the input signal increase is much less than the decrease,the pulse feedback of the inlet pressure is applied on the increase side.It is shown that the overshoot and pressure impact are eliminated by a large margin.This contributes to improve the valve control performance and further extend the application of water hydraulic pressure proportional control.