Robust PID Controller Design for a Real Electromechanical Actuator

Electromechanical actuators (EMA's) are of interest for applications that require easy control and high dynamics. In this paper, we design a robust PID controller for position control of a real electromechanical actuator. An EMA is modeled as a linear system with parametric uncertainty by using its experimental input-output data. PID controllers are 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 EMA control system is passed to the Bialas' test, and validated on the basis of meeting a desired set of specifications. The effects of parameter variations on the system's stability and performance are analyzed and the simulation and test results show that the EMA with the new controller, in addition to robustness to parametric uncertainties, has better performance compared to the original EMA control system. The simulation and test results prove the superiority of the performance of the new EMA over the original EMA control system pertaining to its robustness to parametric uncertainties.