Robustness in dynamic impedance matching of actuator

If actuators can work stably and their output characteristics are robust with varying load and frequency, it is very easy to design and control general-purpose machines that have such load-varying free actuators. We have proposed the control idea to make actuators robust under varying load, called Dynamic Impedance Matching of Actuators, so that the output of an actuator is not influenced by load over a certain range of frequency. In this paper, we look into the stability condition of this control and find the relationship of the phase constraint between Dynamic Impedance Matching of Actuators and the H_∞ controller that represents robust control, and also try to construct the H_∞ controller by using the idea of Dynamic Impedance Matching of Actuators.