Abstract: A method of force estimation for a minimally invasive medical system comprising a robot manipulator (10). The manipulator has an effector unit (12) equipped with a 6-degrees-of-freedom (DOF) force/torque sensor and is configured to hold a minimally invasive instrument (14) having a first end (16) mounted to the effector unit and a second end (20) located beyond an external fulcrum (23) that limits the instrument in motion, usually to 4 DOF. The method comprising the steps: —determining a position of the instrument relative to the fulcrum; —measuring by means of the 6-DOF force/torque sensor a force and a torque exerted onto the effector unit by the first end of the instrument; and —calculating by means of the principle of superposition an estimate of a force exerted onto the second end of the instrument based on the determined position, the measured force and the measured torque.

Abstract: A robotic surgical system for performing minimally invasive medical procedures includes a robot manipulator for robotically assisted handling of a laparoscopic instrument having a manipulator arm, a manipulator wrist supported by the arm and an effector unit supported by the wrist, wherein the manipulator arm provides three degrees-of-freedom by means of a first joint, a second joint and a third joint, each having an associated actuator, for robotically positioning the wrist, the wrist providing two degrees-of-freedom by means of a fourth joint and a fifth revolute joint having an associated actuator, for robotically setting the yaw angle and the pitch angle of the effector unit respectively; the effector unit includes a laparoscopic instrument actuator and provides one degree-of-freedom by means of a revolute sixth joint having an associated actuator for robotically setting the roll angle of the LIAs which includes a seat with an associated coupling mechanism for mounting an instrument stem adaptor to the ef