Rendering of virtual fixtures for MIS using generalized sigmoid functions.

To avoid undesired collisions and improve the level of safety and precision, artificial potential field (APF) can be employed to generate virtual forces around protected tissue and to provide surgeons with real-time force refection through haptic feedback. In this paper, we propose a potential field-based force model using the generalized sigmoid function, and show that it can represent a large class of shapes. The proposed approach has several advantages such as computational efficiency, easily adjustable level of force reflection, and force continuity.