2008 年 74 巻 4 号 p. 400-404
We present theoretical and experimental analyses of an optical attitude sensing system for an MRI-compatible surgical assist manipulator using a spherical ultrasonic motor. In the system, a laser light passes through an optical fiber to a flat mirror of a spherical rotor; the reflection from the mirror is caught by optical fibers. The observed light intensity is converted to attitude information by a neural network, and the rotation of the spherical rotor is detected. The system uses optical fibers and allows the spherical rotor to be miniaturized and inexpensive. In this report, we developed the optical attitude sensing system and tested the drive of spherical ultrasonic motor with the sensing system. As the result, the attitude sensing resolution was less than 0.5°. The sensing system has indicated the feasibility for the control of the manipulator.