Addressing the large applications gap between macroscopic motors and micro-electromechanical systems, Nanomuscle actuators from Steadlands International (Northumberland, UK) use the properties of shape-memory alloys to create tiny actuators that can be produced at a fraction of the size and cost of traditional electric motors. In contrast to the coils, magnets and gears used in a motor-powered actuator, the Nanomuscle has a single working part – a long, hair-thin wire of nickel-titanium alloy. When a current passes through the wire, the resistive heating of the current causes the wire to contract, providing the basic actuation function. The actuator moves through a distance of 4mm and develops a force of 70g, yet the entire device is only the size of a paper clip and operates from a 4V supply using only 470mA. The Nanomuscle is ideally suited to applications such as toys, medical devices, read/write head mechanisms in disk drives, disk ejection mechanisms in computers, and automotive applications such as mirror-adjusting mechanisms.
