Actuator, and robot, brace, and haptic device including the same

An actuator comprising:

• a plurality of wires, one end of each wire of the plurality of wires being engaged with a load;
• a support member, another end of each wire of the plurality of wires being fixed to the support member;
• and
• a drive source configured to rotate the support member to thereby twist the plurality of wires together, wherein:
• the actuator is configured to change, in accordance with the rotation of the support member, a spacing between the support member and the load between at least (i) a first distance, (ii) a second distance at which the spacing between the support member and the load is less than the first distance, (iii) a third distance at which the spacing between the support member and the load is greater than the first distance, and (iv) an operation starting distance at which the spacing between the support member and the load is greatest;
• when the spacing is at the first distance, the plurality of wires are twisted together in a first twist rotation direction;
• when the spacing is at the second distance, the plurality of wires are further twisted together in the first twist rotation direction;
• when the spacing is at the third distance, the plurality of wires are not twisted together but each wire of the plurality of wires is itself individually twisted in the first twist rotation direction;
• and
• when the spacing is at the operation starting distance, the plurality of wires are twisted together in a second twist rotation direction opposite to the first twist rotation direction.