H∞ control design for joint torque control of two-inertia systems

In this paper, a joint torque control problem for two-inertia systems is considered. To attain robust performance and good tracking, a two degrees of freedom control system is designed by using the H
_∞
loop shaping method which is based on the normalized coprime factorization. The joint torque is estimated using the motor angle with Kalman filter, and the estimated value is used as the output of an augmented plant.