Development of a Small Actuator with Three Degrees of Rotational Freedom (3rd Report)

A miniature friction drive 3-D. O. F. actuator has been developed for downsizing of mechanical systems. This actuator consists of a spherical rotor and several drive units. Each drive unit has a truss structure composed of three piezoelectric actuators. The rotor is driven by frictional force generated between the rotor and the drive units. In this paper, the spherical actuator design is referred. And then, its performance is verified by some experimental results: the maximum torque is 2.5 N·cm, the maximum rotational speed is 560°/s. Moreover, the rotational angles are controlled using a position sensing detector experimentally and these experimental results almost coincide with computational simulation results.