CONTROL OF A SURGICAL INSTRUMENT HAVING BACKLASH, FRICTION, AND COMPLIANCE UNDER EXTERNAL LOAD IN A SURGICAL ROBOTIC SYSTEM

For control of a surgical instrument in a surgical robotic system, multiple actuators establish a static pretension by actuating in opposition to each other in torque control. The static pretension reduces or removes the compliance and elasticity, reducing the backlash width. To drive the tool, the actuators are then moved in cooperation with each other in position mode control so that the movement maintains the static pretension while providing precise control.