MRI-compatible micromanipulator: Positioning repeatability tests & kinematic calibration.

In this paper, we report results from positioning repeatability tests and kinematic calibration of our magnetic resonance imaging (MRI)-compatible micromanipulator. This manipulator provides medical and biological scientists with the ability to concurrently manipulate and observe micrometer size objects inside an MRI-gantry. We have already reported on its design, implementation, and the results of preliminary testing of MRI compatibility. Here we test positioning repeatability, which is essential for micromanipulation. The results show that the manipulator has high repeatability (0.7 microm in longitude and 3.0 microm in latitude). In addition, we performed a calibration of kinematics and discussed the experimental result in comparison with the theoretical model. The results show that its workspace is 50-70% smaller than theoretically expected. The results also show that the absolute positioning errors are 16, 9, 5 microm in x, y, and z directions, respectively.