Open-loop bilateral teleoperation for stable force tracking

Traditional bilateral teleoperation communicates both motion and force information explicitly between master and slave devices. Any such closed loop architecture trades off performance with potential instability, especially when using force measurements of high inertia slaves contacting stiff environments. More conservatively, open-loop architectures avoid stability issues, transmitting motion commands while allowing any force feedback only via sensory substitution. We propose open-loop bilateral teleoperation as an alternative communicating force information explicitly and restricting motion information to visual feedback. This naturally matches a user´s needs, seeing motion and feeling forces. A user study was conducted to compare the novel user interface to three common open loop and bilateral control methods: position control, position control with force feedback, and rate control. The results of this study show that users are able to achieve superior force tracking with little tremor. Position tracking and trial completion time suffered from the lack of direct position connection, but training provides a promising method to restore this performance.