Abstract
To overcome the difficulties associated with minimally invasive surgery, we have developed a magnetic resonance (MR)-compatible compact surgical robotic system. This system uses MR-guided navigation and can augment the surgeon’s eye-hand skills that are limited by endoscopic surgery. To achieve MR-compatibility of the manipulators, we had to provide remote actuation of joints from the ultrasonic motors located and driven at least 750[mm] away from the center of the MRI. We then developed a new surgical instrument and a novel tube-rod transmission mechanism comprised of a flexible PEEK® rod encased in a Teflon® tube, as well as a technique for controlling the transmission mechanism. It was found that stiction force had a significant impact on the stiffness of transmission using a parameter estimation method. We derived an algorithm to compensate for the expansion of the rods that occurred so we could negate the stiction force. The result of the compensation showed that the time delay between the reference to the ultrasonic motor and the movement of the joint was reduced from 600 to 80[ms]. Using the master-slave manipulator system with the tool and the transmission mechanism, we were able to perform each primitive motion of a suturing task for training material.
