A suppression of cut-off frequency fluctuation based on workspace observer with estimated equivalent mass for MDOF bilateral system

In the motion control method based on workspace observer with the constant nominal equivalent mass, the posture change of the system may cause the fluctuation of cut-off frequency of workspace observer due to the variation of the equivalent mass in workspace. This paper investigates the effect of the cut-off frequency fluctuation in workspace observer to the motion control performance. The utility of a suppression method of cut-off frequency fluctuation based on workspace observer with the estimated equivalent mass is discussed. Then, a multi-degrees-of-freedom (MDOF) bilateral motion control method based on workspace observer with the estimated equivalent mass is proposed. The validity of the proposed control method is verified from the experimental results on a two-degrees-of-freedom master-slave system with different configurations.