Multi degree of freedom spherical ultrasonic motor

This paper presents a multi-degree of freedom spherical ultrasonic motor. As a prototype spherical ultrasonic motor, the authors have successfully developed two kinds of spherical ultrasonic motor with two degree of freedom. Each type has good controllability; the motor can drive a spherical rotor about an arbitrary axis; the maximum speed is 30 rpm; the maximum output torque is 0.7 kg cm; the maximum positioning error is 0.3 mm. It is expected to be applied to not only a robotic manipulator´s actuator but also an assembling machine, laser cutting and many other fields