A Multirate Energy Bounding Algorithm for High Fidelity Stable Haptic Interaction Control

This paper presents multirate energy bounding algorithm to provide high fidelity stable haptic interaction. Stable haptic interaction control algorithms such as virtual coupling or time-domain passivity algorithm has been studied by many researchers. For slowly-simulated virtual environments, however, the deterioration of realistic haptic feeling is unavoidable because these algorithms require high update rate. For high fidelity haptic interaction, we propose multirate approach that separates haptic thread and low-level control thread. A haptic thread carries out calculating the virtual environments force at slow rate while low-level control thread executes determining the actuator force by the energy bounding algorithm at high update rate. Experiments using commercial haptic device have been performed to show the efficiency of the proposed algorithm. As a result, we confirmed that the response was stable and displayed stiffness was much increased even though the haptic rendering rate was slow