Multiple Resonant Load Characteristics and Control Strategy of Electro-Hydraulic Actuator for Launch Vehicles

The China's new generation of launch vehicles adopt high thrust liquid oxygen-kerosene engines, aiming at its load characteristics of heavy inertia, low structural natural frequency and multiple resonance frequency, a high-order spring-mass physical model and a normalized control model of an electro-hydraulic actuator were developed. A combined control strategy based on the whole interested frequency range was proposed, including the piecewise feed-forward, the nonlinear PID and the multiple notch filter. The parameters of the normalized control model were identified by the frequency scanning tests of electro-hydraulic actuators frequency and optimized based on Particle Swarm Optimization algorithm. The approach has been demonstrated by simulation analysis and trial experiment, the dynamic performances met all the amplitude and phase requirements at the selected frequencies of the electro-hydraulic actuators for launch vehicle. The result shows that appropriate high-order normalized control model and combined control strategy are enabling contributors to obtain satisfactory high dynamic performance.