Real-Time High Bandwidth Feedforward Position Control of Electro-Hydraulic Actuator Using Non-Minimum Phase Inverse Model

In this paper, real-time feedfoward position control algorithm of electro-hydraulic actuator (EHA) is proposed. To reduce nonlinearity of EHA, model uncertainty and disturbance, feedback system with proportional-integral-derivative (PID) controller is used. The feedback system is estimated as linear dirsrete time transfer function by recursive least squares algorithm. Feed-forward controller using inverse model generates filtered signals that compensate magnitude and phase of feedback system. For high bandwidth control, fast sample rate is necessary and it causes NMP zeros of estimated transfer function. The NMP transfer function is inversed by zero phase error tracking control (ZPETC) method and the inverse model is used to feedforward controller. The real-time experiment is conducted by NI-CompactRio and Labview, and the simulation is programmed in MATLAB/Simulink. The results of simulation verify the validity of proposed control strategy.