Direct Impulse-based Rendering in Force Feedback Haptics

In certain haptic applications, producing a sharp feeling of impact is important for high-fidelity force feedback rendering of virtual objects. This paper studies the direct impulse-based rendering paradigm to achieve this goal. Three main challenges are identified and some solutions are proposed. The first one is the energy deviation due to the sampled-data settings. Since the deviation tends to have a dissipative nature, it is called unsolicited dissipation and is suggested to be countered by applying a larger adaptive coefficient of restitution based on energy monitoring. The second challenge is the actuation limits which can be met by distributing the impulse into a sequence of force commands over successive intervals. The third is rendering resting contacts which is proposed to be done using a hybrid penalty-impulse-based technique. This paper develops a systematic way for collecting all the required mathematical formulations, analysis of the aforementioned issues and implementation of the solutions within a unified controloriented framework entitled the generalized contact controller (GCC). Our initial simulation and experimental results show the promising aspects of the direct impulse-based rendering and the GCC framework for generating a sharper unfiltered feeling of impact at relatively low sampling rates compared to virtual coupling-based indirect methods.