A Universal and Inexpensive Servomotor for Vestibular Research

Rotations of any type over 300°in the horizontal plane are produced by this motor controller for vestibular research. This dc motor produces 1.28 N ·m(0.94 ft ·Ib) of torque and is powered by a pulse-width-modulated (PWM) amplifier. Turntable angle is fed back via a potentiometer. For large movements, the motor produces maximum torque for acceleration and maximum reverse torque for deceleration (bang-bang control). When the error is small, linear control is used. For a monkey and turntable of 0.31 kg ·m2 inertial load, the motor produces 240°/s2 acceleration. The system costs $ 450.