Controlling stiffness is critical in procedures using soft surgical robots. In the final year of the STIFF-FLOP project, the University of Surrey developed a methodology to characterise the tuneable dynamic stiffness matrix and demonstrated its use for rejecting lateral and normal disturbances. This method of disturbance rejection was employed in conjunction with granular jamming to maintain the tip position of a three-segment STIFF-FLOP robot.
It is noted that this algorithm can be extended to multi-module soft robots. The research conducted by UoS verified why the reduction of stiffness at the tip is preferred for safety whilst greater stiffness is essential to undertake efficient tissue manipulation with surgical tools.
Furthermore, information on the forces exerted at the distal end of the robot manipulator and appropriate feedback control improved the robustness of motion of the system and contributed to the improvement of robot-environment interaction safety through precise manipulation.
Read more: Controlling The Stiffness