A Force Display Algorithm for Virtual Environments

Graphic simulators are currently used in application such as off-line teaching tasks on industrial robots and CAD systems. While recent advances in computer graphics have led to the development of high powered computers with high quality static and dynamic graphics, the display of kinesthetic information is still lacking. This display of kinesthetic information is critical for the development of simulators that can more accurately and realistically present simulated objects to the user. With this problem in mind, this paper proposes a method of calculating interaction forces produced in the simulation world. These forces are effectively used in a simulator where contact forces are felt by the user through its forcereflecting handle. In this method, two fundamental contacts, Face-Vertex and Edge-Edge, will be introduced, and the interaction force calculations will be defined. It will be demonstrated that every contact between two convex polyhedral objects can be described using this set of the fundamental contacts. The interaction forces will be determined from the sum of forces calculated at each fundamental contact. Using a simulator system which displays forces, certain preliminary experiments are carried out and the effectiveness of the method confirmed.