Compliance control for stabilization of bilateral teleoperation system in the presence of time delay

Bilateral teleoperation is one of the promising technologies and enables us to work in the distance. However, the time delay in network seriously deteriorates the performance and possibly makes the system unstable. The authors previously proposed architectures with high transparency for delayed bilateral teleoperation system, which are the P-F architecture and the F-P architecture. However, these architectures are quite unstable. The P-F architecture can contact soft and hard environment by introducing the damping. On the other hand, the F-P architecture cannot contact hard environment even if the damping is introduced. Therefore, this paper proposes the stabilization method especially for the F-P architecture. The proposed method introduces the compliance control in differential mode in the F-P architecture. The compliance control in differential mode provides stability, but position error occurs instead. Therefore, this paper also proposes the switching procedure so the F-P architecture can have compliance only against hard environment. The effectiveness of the proposed method is validated experimentally.