The 6-DoF Implementation of the Energy-Reflection Based Time Domain Passivity Approach with Preservation of Physical Coupling Behavior

Abstract

Instability due to delayed communication is one of the main challenges in the coupling of autonomous robots but also in teleoperation with applications reaching from space to tele-healthcare scenarios. The Time Domain Passivity Approach assures stability despite delay and has already been validated in teleoperation scenarios from the International Space Station. It has been improved by a method considering energy reflection of the coupling controller recently. This extension has been shown to provide better performance in terms of position tracking and transmitted impedances which promises increased transparency for a human operator. This paper presents the 6-DoF implementation of the energy-reflection based approach and of an extended gradient method which promises to maintain the physical coupling behavior despite delay. An intense experimental validation confirms the performance increase due to both methods at delays up to 600ms in the 6-DoF case.