Identification, uncertainty modelling, and robust controller design for an electromechanical actuator

There are more trends to use electromechanical actuator (EMA) in aerospace and robotics applications which require easy control, high efficiency, and high dynamics. This paper deals with experimental identification, uncertainty modeling, and robust PID controller design for position control of a real EMA. It is identified and modeled as linear system with parametric uncertainty and time delay by using its experimental input-output data. The captured data, related to several experiments at different conditions, were used for model estimation and validation purposes. Robust PID controller is designed by graphical findings of the regions of stability with pre-specified margins and bandwidth requirements and by applying the complex Kharitonov´s theorem. This novel method enables designers to make the convenient trade-off between stability and performance by choosing the proper margins and bandwidth specifications. The simulation and test results prove the superiority of the performance of this new EMA over the original EMA control system; this preference is pertaining to its robustness to parametric uncertainties.