High Fidelity Haptic Rendering of Frictional Contact with Deformable Objects in Virtual Environments using Multi-rate Simulation

Haptics is an increasingly common modality in human-computer interfacing. The focus of this paper is the problem arising from the difference between the high sampling rate requirements of haptic interfaces and the significantly lower update rates for physical models simulated in virtual environments. This is a critical problem, especially for applications involving haptic manipulation of deformable objects simulated in virtual environments, such as in surgical simulation. In this paper, a multi-rate simulation approach was developed to address this problem. The proposed method employs linear low-order approximations to model the inter-sample behavior of the high-order non-linear deformable object models. The basic method is also extended to achieve high-fidelity rendering of haptic manipulations involving sliding-type frictional contact. The proposed approach uses a local geometric model in addition to the local dynamic model, and performs collision detection and response as part of the high update rate haptic loop. Experimental results that validate the proposed methods are also presented.