Closed-loop force control for haptic simulation of virtual environments

Abstract

Force feedback control is investigated for improving the quality of the haptic feedback in virtual reality applications. Advanced control design can increase the transparency of the haptic device at the haptic interface thereby increasing the realism of the simulation. Force feedback also enables the implementation of admittance control approaches heretofore considered the domain of large robotic platforms. The quality of the haptic interface is "rst quanti"ed, and the standard open-loop impedance approach to haptic control is reviewed. Dual-input control schemes with sensory force feedback are then introduced, and the resulting quality of the haptic interface is derived. A four-bar linkage example is used to illustrate the im- provement in "delity realized with the various approaches. The tradeoffs encountered in moving to force feedback controllers for haptic applications are also discussed.