Design Parametrization for Dynamically Similar Delayed Teleoperation Systems

摘要

Bilateral teleoperation system are prone to instability coming out from the time-delay introduced by the indeterministic communication channel. This problem has been subject of intensive research under the assumption of non-equal master-slave teleoperators, however, dynamical similarity of master-slave robots can always be induced by proper tuning of feedback gains in the controllers, based on the physical ratio of both robots When we consider a linear Dynamically Similar Teleoperation System (DSTS), there arises advantages, observed heuristically in several experiments [1] or analytically in [10]. In this paper, a simple yet important parametrization trade-off of feedback control gains and performance teleoperation parameters is presented that allows an easy way to achieve stability or even also passivity. The analysis is based on an an impedance control scheme reported in [2] when the time-delay in the communication channel is considered constant but unknown. Stability and passivity limits are obtained based on Llewellyn's and Raisbeck's criteria.rnThis result explicitly suggests clearly guidelines among key factors, such as time delay, desired velocities and feedback gains in terms of the scaling parameters, arises a clear advantage when dealing with dynamically similar systems. This explains why the transparency of the teleoperation system, also studied under the same control law in [10] is improved by augmenting/reducing the dynamic/kinematic scaling factor, for given desired frequency, time delay and feedback gains.