3 Dynamic Proxies and Haptic Constraints

Abstract

Haptic simulations strive to provide users with realistic renditions of virtual environments but often struggle to display convincing rigid constraints or impacts. They generally utilize a proxy representation of the physical haptic device inside the virtual world to detect collisions, enforce constraints, and compute feedback forces. Traditional implementations are quasi-static and do not capture the dynamic energy and momentum transfer of impacts nor the associated characteristic impulse forces. To further the development of haptic interactions, we introduce and explore the concept of dynamic proxies. Associating dynamics with a proxy allows greater control over its motion and behavior and enables a general force-based simulation framework. We suggest first-order, massless dynamics to maintain a light feel and low computational update rate, while easily incorporating collisions and constraints as velocity limits. User feedback is improved and may include acceleration terms to replicate any sudden momentum changes. The resulting system shows greater realism and flexibility, allowing extensions to multi-user/multi-proxy applications with dynamic interactions.