H∞ design using normalized coprime factors: an application to an electromechanical actuator

Applies an H_∞ control law to a testing bench composed of an electromechanical actuator. The authors present the plant model which takes into account external disturbances and uncertainties such as non-linearities and unknown parameters. The H_∞ design is based on normalized coprime factor plant. To define the frequency weighting functions, a loop shaping procedure is used to allow the specification of performance and robust stability characteristics. The loop shape is used as a measure of the trade-off between closed loop performances and robust stability. The obtained results are compared with those given by LQG and LQG/LTR designs