Abstract: Broadly speaking, embodiments of the present techniques provide methods for driving shape memory alloy (SMA) actuator wires in a more power-efficient manner.

Abstract: Broadly speaking, embodiments of the present techniques provide methods for driving shape memory alloy (SMA) actuator wires in a more power-efficient manner.

Abstract: Broadly speaking, embodiments of the present techniques provide methods for driving shape memory alloy (SMA) actuator wires in a more power-efficient manner.

Abstract: An actuator assembly comprises a static part and a movable part. A helical bearing arrangement supporting the movable part on the static part guides helical movement of the movable part with respect to the static part around a helical axis. One or more actuators, that are not shape memory alloy actuators, are arranged to drive movement of the movable part around the helical axis, which thereby includes a component of translational movement along the helical axis. The helical movement increases the force within the actuator assembly allowing actuation of heavier movable parts, and may improve posture.

Abstract: Broadly speaking, embodiments of the present techniques provide methods for driving shape memory alloy (SMA) actuator wires in a more power-efficient manner.

Abstract: A shape memory alloy actuation apparatus comprises a support structure (2) and a movable element (10). A helical bearing arrangement (20) supporting the movable element on the support structure guides helical movement of the movable element with respect to the support structure around a helical axis (H). At least one shape memory alloy actuator wire (60) is connected between the support structure and the movable element in, or at an acute angle to, a plane normal to the helical axis, so as to drive rotation of the movable element around the helical axis which the helical bearing arrangement converts into said helical movement.