Motion constraint design and implementation for a multi-functional virtual manipulation system

Simulation systems nowadays are applied to various tasks, and thus demand a versatile manipulative system for the user to interact with the corresponding simulated environments. To make a single manipulative device applicable to more different kinds of tasks, the concept of virtual mechanisms has been previously proposed, in which virtual motion constraints are constructed via the software to constrain the manipulative device to move within a limited workspace that corresponds to task requirements. Motivated by the idea, in this paper, we propose a systematic approach to design and implement the virtual motion constraints for a multi-functional virtual manipulation system. The motion constraints are generated from sets of virtual walls to deal with the compliance task. And, a pixel-based method is proposed for smooth force rendering between the walls. In experiments, we apply the proposed virtual manipulation system to emulate an omni-directional wrench and a manual gearshift system, based on using a 2-DOF force-reflection joystick. We also evaluate the responses of the users during the manipulation of these two virtual mechanisms, which implicate the proposed system is able to capture the main features of various kinds of manipulative devices.