Toward Transparent Virtual Coupling for Haptic Interaction during Contact Tasks

Abstract

Since its introduction (e.g., [4,6]), virtual coupling technique has been de facto way to connect a haptic device with a virtual proxy for haptic rendering and control. However, because of the single dependence on spring-damper feedback action, this virtual coupling suffers from the degraded transparency particularly during contact tasks when large device/proxy-forces are involved. In this paper, we propose a novel virtual coupling technique, which, by utilizing passive decomposition, reduces device-proxy position deviation even during the contact tasks while also scaling down (or up) the apparent inertia of the coordinated device-proxy. By doing so, we can significantly improve transparency between multiple degree of freedom (possibly nonlinear) haptic device and virtual proxy. In other to use passive decomposition, disturbance observer of [3] is adopted to estimate human force with some dead-zone modification to avoid "winding-up" force estimation in the presence of device torque saturation. Some preliminary experimental results are also given to illustrate efficacy of the proposed technique.

Fast and Accurate Data-Driven Simulation Framework for Contact-Intensive Tight-Tolerance Robotic Assembly Tasks

“…We further formulate our simulation framework Fig. 17: Schematic of haptic rendering of virtual bolting task, consisting of our proposed simulation pipelines for the bolting task, with the nut dynamics coupled with a haptic device via the transparent virtual coupling [37], [43] and a visualization display.…”

“…15: Snapshots of experiment and simulations with the K-means/PGS method and our proposed framework with their contact force plots for the narrow generalization performance verification. from its relying on the discrete-time passive PMI [1], it can substantially enhance the interaction stability of the haptic rendering with human operators, while also being compatible to standard technqiues for haptic rendering/control such as four-channel transparent virtual coupling [42], [43] even with some delay [44]. Shown in Fig.…”

Improving transparency of virtual coupling for haptic interaction with human force observer

“…[30], yet, the issue of passivity was completely neglected and experimental result was also limited only to a simple two-DOF planar interaction there. In contrast, the current manuscript features a new experimental passivity analysis to show that our proposed virtual coupling is passive when the inertia scaling η is not so small, and also a theoretical justification on why this is the case by relating the inertia scaling, the system dynamics, and the human force observer bandwidth.…”