Rotational actuator

摘要

A rotational actuator includes an actuator case, a first rotor supported on the actuator case for rotation about an axis of rotation, a second rotor supported on the actuator case coaxially with the first rotor and for rotation independent of the first rotor, an expandable member having one end secured to the second rotor and the other end secured to the first rotor for relatively rotating the first and second rotors by expansion or contraction thereof, and an expandable member controller for controlling the extent of expansion and contraction of the expandable member. The momentum of the first rotor in the rotational direction thereof when the expandable member is expanded or contracted is set to be higher than the momentum of the second rotor in the rotational direction thereof at this time.