Abstract: An actuator assembly (2) comprising: first (50) and second (60) parts that are movable relative to each other; and one or more actuating units, each actuating unit comprising: a force-modifying mechanism (72) connected to the first part (50); a coupling link (78) connected between the force-modifying mechanism (72) and the second part (60); and an SMA wire (80) connected between the first part (50) and the force-modifying mechanism (72) for applying an input force on the force-modifying mechanism (72) thereby causing the force-modifying mechanism (72) to apply an output force on the coupling link (78) and causing the coupling link (78) to apply an actuating force on the second part (60); wherein the coupling link (78) is compliant in a direction perpendicular to the direction of the actuating force.

Abstract: An actuator assembly (140) comprises first and second parts. A first axis (Z) is defined with reference to the second part. The actuator assembly (140) comprises shape-memory alloy wire (80) connected between the first and second parts for moving the first part relative to the second part in any of a set of directions that are at least partly perpendicular to the first axis (Z). The set of directions includes first and second directions. The actuator assembly (140) comprises a set of arms (170), each of which is connected between the first and second parts and extends partly around the first axis (Z). The set of arms (170) is configured to provide a biasing force that biases the first part towards a first position relative to the second part. The set of arms (170) has a first stiffness when the first part is moved away from the first position in the first direction and a second, lower stiffness when the first part is moved away from the first position in the second direction.