On robust position control of DC motors by ǫ-PID controller and its application to humanoid robot arms ⋆

In this paper, we propose a new ǫ-PID controller for DC motors. We provide a systematic design steps of selecting the gains of the proposed ǫ-PID controller. We also analytically show that the proposed controller provides robustness against system parameter uncertainty and reduces the effect of unknown load torque to the order of ǫ. The benefit of our control approach is that the PID gains are tuned conveniently by adjusting a single ǫ gain-factor. An experiment of DC motor control with its application to humanoid robot arms demonstrates the practical aspect of the proposed control method.