Dynamic task/posture decoupling for minimally invasive surgery motions: simulation results

This paper deals with the use of an original dynamic task/posture decoupling control algorithm that allows a robot to achieve motions under the constraint of moving through a fixed point. This work takes place in the context of minimally invasive surgery where the tool is telemanipulated by the surgeon through a penetration point: the trocar fixed on the patient. The algorithm is based on the dynamic control in the operational space of a redundant robot: the total control torque is decoupled into a task behavior torque and a posture behavior torque. By minimizing the contact force applied to the trocar (or equivalently, by forcing to zero the distance between the instrument passing through the trocar and the current location of the trocar), we compute the posture behavior torque guaranteeing that the trocar constraint is satisfied. Simulation results highlight the performance of this algorithm for various trajectories such as straight lines and circles.