Pressure loop control of pump and valve combined EHA based on FFIM

Based on the specificity of pump and valve combined EHA that valve control loop response higher than pressure loop and the characters of time-varying, nonlinearity of pressure loop, the feed-forward fuzzy immune (FFIM)control algorithm was proposed to adjust PID control parameters real time and increase response and control capability of pressure loop, through add error signal to position loop as feed-forward signal, and using immune algorithm adjusting pressure loop control parameters real time which has optimizing performance and using fuzzy algorithm as operator function. The simulation result shown the response of pressure loop was increased by add feed-forward signal, but the pressure value rising, and immune algorithm reduces the pressure fluctuation around the pressure setting value. The joint of feed-forward and immune not only increase the response but also decrease pressure fluctuation and increase the control capacity to complex characters of pressure loop.