A New Approach to Haptic Rendering by Position Control

Conventional force rendering methods in haptic applications often suffer stability issues when simulating stiff objects such as a virtual wall. This paper argues that the emphasis in such scenarios is to minimize the penetration into the virtual wall instead of emulating the force to the operator. Therefore, position controllers are developed to achieve better haptic rendering of the virtual wall. The new rendering method is implemented on a complex 6-DOF parallel structure haptic device. The position controllers are developed by both LQR and 6-joint independent PID methods. The control method exploits model-based development tools to obtain the linear control system model without deriving the mathematical model of the complex haptic device. The performance of the two controllers is compared on a simulated prototype of the haptic device.