(A) performance index for bilateral teleoperation : telepresence index

Abstract

This thesis proposes a performance index called Telepresence index for bilateral teleoperation, which can be used both for the performance evaluation of bilateral control architectures and for design purposes. This index is intended to represent a comprehensive performance objective consisting of kinematic correspondence and transparency, two major performance objectives of bilateral teleoperation. In order to quantify the performance objective, telepresence index has employed a novel method using error vector magnitude, which enables a seamless combination of magnitude and phase error and accommodation of time delay. In comparison with existing performance indices, it was observed that telepresence index possesses the comprehensiveness of performance objectives, magnitude/phase integrity, and the capacity to include time delay, which the others lack in one way or another. The index was applied to evaluate the performances of three widely known control architectures: PD-type bilateral control, Ueda’s ideal control, and scattering-based control. In all cases, telepresence index has been compared favorably with the other indices, in terms of clarity, convenience and accuracy, thereby demonstrating its improvement. Based on the telepresence index, the application of the telepresence index was investigated. A gain optimization method was proposed by combining the telepresence index and genetic algorithm, and its convenience and reliability for designing control gains was verified by a numerical example. Moreover, a novel control architecture, modified PD-type bilateral control, has been proposed with the insight of comprehensive performance objective from the telepresence index. The performance improvement of this control architecture was also verified by a numerical example in comparison with existing PD-type bilateral control. As a practical example, the telepresence index and its applications have been applied to teleassessment tasks, a kind of telerehabil...