Development of a Parallel Actuation Approach for MR-Compatible Robotics

In recent years, the use of robotics to augment MRI diagnostic and interventional procedures has increased significantly. However, the demanding MRI environment precludes the use of most common actuation approaches. Alternative actuation concepts have been proposed but these solutions do not lend themselves to linear control structures. We present a new actuation method, using the motion of parallel ultrasonic motors combined through a differential mechanism, to address these limitations. Specifically, the approach eliminates the nonlinear velocity dead band and velocity reversal time delay characteristic of MR-compatible ultrasonic actuators. A prototype of this device is constructed and evaluated. Results demonstrate the viability of the proposed approach for linear position control and telerobotic applications.