Force-driven robotic drag control for freehand 3D ultrasound-guided robot-assisted percutaneous surgery

Freehand 3D US-guided robot-assisted percutaneous surgery system, presently under development in our laboratory, has the potential to overcome some drawbacks of current conventional clinical interventions. The robot is commanded to insert accurately the needle into the target in patient's body according to planned path in the 3D model reconstructed by freehand 3D US by several separate steps, one of which is to move the needle tip to the selected insertion point on the surface of the skin. In this paper, we present a force-driven robotic drag control algorithm, designed to transform axial drag force signal of the force sensor mounted approximate to the needle propeller into motor pulse signal of the corresponding axis, to allow the surgeon to drag the robot and lead the needle tip to the entry point manually and flexibly. Experiment has been conducted to validate the algorithm performance.