Force Feedback Augmentation Modes in the Laparoscopic Minimal Invasive Telesurgical System

The proportional-integral (PI) gain scheduling full force feedback control (3 translational + 1 gripping degrees of freedom) on the dual-arm master/slave tele-surgical manipulator system has been implemented. Gain scheduling algorithm provides to the operator the maximum allowable force perception, while retaining the stability of the system manipulation with different environment. It is a way to cope with the instability caused by the motor saturation as well. Local force feedback configuration naturally compensates for the inherent inertia of the master manipulator in addition to precise display of the interaction force. It has been observed that, during the operation, the surgeon often needs to concentrate on force in some directions than others. Also, the organs involved in the abdominal laparoscopic surgery tend to yield very small initial reaction force, which might be difficult to perceive. With the consideration of the performed task and tissue mechanical properties, reaction force in those directions will be amplified while the others will be sent normally. Eight force feedback augmentation modes have been prepared. A switching algorithm has been developed to automatically change the augmentation mode appropriately according to the position and force signals. Surgeon thus can focus more on the operation task