Magnetically compatible robots are required as haptic interfaces for neuroscience studies. The purpose of this paper is to develop an MR compatible robot using ultrasonic motor, which is able to work within an MRI/fMRI scanner and to acquire MRI images continuously during finger motions. In addition, the force field control method of ultrasonic motor is discussed. The characteristic of voltage phase and motor torque is investigated experimentally, and these results are used for the force field control of ultrasonic motors. The position dependent force fields and velocity dependent force fields are evaluated with a force sensor. Also, MR compatibility is verified experimentally. Finally, some brain activities are investigated with fMRI during finger movements.
