Enhancement of Stability and Transparency in Teleoperated Robots Through Isotropy-Based Design

摘要

The primary challenge in implementing teleoperated master-slave robots is that both of its objectives - stability and transparency, are conflicting to each other. This trade-off is usually attributed to the time-delay in the communication channel, and state-of-the-art controllers are proposed primarily to counteract the effects of this time delay. Despite such controllers, it is observed that the system suffers from instability and inaccurate force feedback (loss of transparency), at least under certain conditions. This is because issues other than time delay which cause oscillations and inaccurate force feedback are rarely addressed in the literature. In this paper, such issues are clearly identified and it is shown here that controller design cannot counteract these issues. It is proposed in this paper that an isotropy based design of robots is necessary for recovering the additional stable and transparent behavior of the system, apart from what a controller can achieve. Another significant contribution of this paper is that because of the proposed design, the need for two signals from the traditional four-channel teleoperation architecture is eliminated, thus reducing the complexity of the system. Experimental validation is carried out by implementing a two-channel architecture on the designed robots.