Motion Canceling Bilateral Control analysis for target with two layer impedance model

Motion Canceling Bilateral Control (MCBC) is one of the tele-operation method which reduces the workload of an operator by synchronizing the robot with a target to treat with. The performance was evaluated by a previous work, but unfortunately in the analysis, target was modeled as one layer impedance. This assumption is valid when target motion and robot motion are independent. Hence in this research, performance and stability of MCBC are analyzed with two layer impedance model consists of target impedance and trajectory impedance. The model expands the applicability of analysis for the case when the target motion is affected by the robot. Frequency characteristics is observed to evaluate the performance and the root locus method is adopted to evaluate the stability. The analyses clarifies that a bandwidth of the impedance transmission is determined by the controller gains, regardless of the target or trajectory impedance. Moreover, operational force is suppressed in wide bandwidth if the target impedance is lower than the trajectory impedance. The root locus method clarifies the relationship between target impedance, trajectory impedance, and stability. The total system become unstable if the target impedance exceeds the trajectory impedance.