ACTUATOR ASSEMBLY

A shape memory alloy actuator assembly is disclosed. The actuator assembly comprises a first part (2002), a first bearing arrangement (2003) and a platform (2004). The first bearing arrangement supports the platform on the first part. The platform is tiltable about first and/or second axes (2011, 2012) which are not parallel and which are perpendicular to a primary axis (2009) passing through the actuator assembly. The actuator assembly further comprises a second bearing arrangement (2005) and a second part (2006). The second bearing arrangement supports the second part on the platform such that the second part tilts with the platform. The actuator assembly further comprises a drive arrangement (2007; Fig. 22) comprising four lengths (20101, 20102, 20103, 20104) of shape memory alloy wire. The four lengths of shape memory alloy wire are connected between the second part and the first part of the actuator assembly. The first bearing arrangement is configured to guide tilting of the platform about the first and/or second axes and to constrain rotation of the platform about the primary axis. The platform defines a first plane (2500; Fig. 25) which is tiltable and which has a normal (2501; Fig. 25) such that tilting the platform tilts the normal away from the primary axis. The second bearing arrangement is configured to constrain tilting of the second part with respect to the platform, to constrain lateral movement of the second part perpendicular to the normal, and to guide axial movement of the second part along the normal relative to the platform. Un ensemble actionneur d'alliage à mémoire de forme est divulgué. L'ensemble actionneur comprend une première partie (2002), un premier agencement de palier (2003) et une plateforme (2004). Le premier agencement de palier supporte la plateforme sur la première partie La plateforme peut être inclinée autour de premier et/ou second axes (2011, 2012) qui ne sont pas parallèles et qui sont perpendiculaires à un axe principal (2009) passant à travers l'ensemble actionneur. L'ensemble actionneur comprend en outre un second agencement de palier (2005) et une seconde partie (2006). Le second agencement de palier supporte la seconde partie sur la plateforme de telle sorte que la seconde partie s'incline avec la plateforme. L'ensemble actionneur comprend en outre un agencement d'entraînement (2007 ; Fig. 22) comprenant quatre longueurs (20101, 20102, 20103, 20104) de fil d'alliage à mémoire de forme. Les quatre longueurs de