Development of an Intra-Operative Active Navigation System for Robot-Assisted Surgery.

Optical tracking system (OTS), an essential component of robot-assisted surgery, measures the position and orientation of the surgical tools during surgery operations. OTS has proven to be a reliable intra-operative navigation method in clinical applications. However, OTS suffers from the vision occlusion where obstacles block the vision of the position sensors of the OTS. To tackle with this problem, we propose an active navigation system which can automatically moves the OTS so as to avoid the occlusion and meanwhile maintain the tracking accuracy. The active navigation system is composed of a multi-DOF robot, an optical tracker and an RGB-D camera. The accuracy of OTS is influenced by several factors, such as working distance and relative orientation of the tracked tool. Since in the active navigation system, the OTS moves during navigation, the impact of the movement of OTS on its accuracy is investigated. The corresponding experiments are conducted, and the results are analyzed. Subsequently, an occlusion avoidance strategy is developed to control the OTS to not only avoid the obstacles but also keep the accuracy degradation acceptable. Ultimately, the occlusion avoidance experiment is conducted to verify the proposed strategy. The experimental results demonstrate the effectiveness of the proposed active navigation system.