Wave-based time delay compensation in bilateral teleoperation: Two-channel versus fourchannel architectures

Abstract — In this paper, two different approaches have been proposed aiming to improve transparency of a passivity-based delay-compensated teleoperation system: direct force reflection in a two-channel wave-based control architecture, which uses the same number of channels as the traditional position errorbased control scheme with wave variables and, four-channel wave-based control architecture, which is capable of achieving ideal transparency in the presence of time delay. In order to present a comprehensive performance comparison, we quantify the transparency of each approach through subjecting the experimental results of a bilateral master-slave system developed for endoscopic surgery applications to identification of the hybrid parameters of the equivalent two-port network. I

Tool/tissue interaction feedback modalities in robot-assisted lump localization

Abstract — Providing a surgeon with information regarding contacts made between tools and tissue during robot-assisted interventions can improve task efficiency and reliability. It is hypothesized that various modalities of contact feedback have the potential to enhance performance in a robot-assisted minimally invasive environment. In this paper, (kinesthetic) haptic feedback is compared with visual feedback of haptic information in terms of several performance metrics. Using a haptics-capable master-slave test-bed for endoscopic surgery, experiments involving a lump localization task are conducted and the performance of human subjects is compared for these two modalities of contact feedback. It is shown that the two feedback modalities result in comparable localization accuracies – an advantage of visual haptic feedback due to the lower system complexity required – while the task completion times are significantly shorter with haptic feedback. I

Stability of Discrete-Time Bilateral Teleoperation Control

Abstract — Discretization of a stabilizing continuous-time bilateral teleoperation controller for digital implementation may not necessarily lead to stable teleoperation. This paper addresses the stability of master-slave teleoperation under discrete-time bilateral control. Stability regions are determined in the form of conditions involving the sampling period, control gains including the damping introduced by the controller, and environment stiffness. Due to the tradeoff between stability and transparency in bilateral teleoperation, such stability boundaries are of particular importance when the teleoperation system has good transparency. I