Robust H∞ feedback compensator design for an electromechanical actuator with time delay

In this paper, a robust feedback compensator is designed for a real electromechanical actuator (EMA) and harmonic drive by introducing a novel procedure based on H control theory. Three main topics are treated; experimental identification, structured and unstructured uncertainties modeling, and robust control design for a real EMA harmonic drive system with time delay. The new approach verifies good trade-off between the powerful H controller and the unique features of feedback compensation, such as simplicity, effectiveness, low cost, and easy implementation. Simulation and test results prove the effectiveness of the approach and the superiority of the performance of the designed robust EMA with feedback compensation based on H controller over the original EMA with classic controller. This superiority is due to the new approach's low sensitivity to parameter variations and simplicity, in addition to its robustness.