Cambridge Mechatronics Limited

Robert Langhorne

Andrew Benjamin Simpson Brown

James Robert Howarth

Robin Eddington

Stephen Matthew Bunting

Martin McBrien

Daniel John Burbridge

Adam South

Emily Kwok

Samuel Armstrong

A shape memory alloy (SMA) actuator assembly comprising: a support structure (); a moveable part () moveable relative to the support structure; at least one SMA wire () having a first portion and a second portion respectively attached to the support structure and the moveable part, the said SMA wire is configured to, on contraction, drive movement in the moveable part at least in a primary axis along which the shortest side of the SMA actuator assembly extends; an intermediate component () engaging the SMA wire at a location between the first and second portions, the second portion of the SMA wire being arranged at an oblique angle to both the primary axis and the first portion of the SMA wire.

Actuator assembly

An actuator assembly comprises: first () and second () parts, wherein a primary axis (P) is defined with reference to the second part; a plurality of lengths of shape-memory alloy wire () connected between the first and second parts, wherein the lengths of wire are configured, when selectively powered, to cause three-dimensional movement of the first part relative to the second part; and a mechanism configured, when the lengths of wire are unpowered, to hold the first part in at least one position and/or orientation relative to the second part against the force of gravity for any orientation of the second part.

An actuator assembly () includes a first part (), a second part (), a bearing arrangement () and a drive arrangement (). The bearing arrangement () includes first to fourth flexures () arranged about a primary axis () passing through the actuator assembly (). The bearing arrangement () supports the second part () on the first part (). The second part () is tiltable about first and/or second axes () which are not parallel and which are perpendicular to the primary axis (). The drive arrangement () includes four lengths of shape memory alloy wire (). The four lengths of shape memory alloy wire () are coupled to the second part () and to the first part (). The bearingarrangement () is configured to convert lateral force(s) normal to the primary axis () generated by the drive arrangement () into tilting of the second part () about the first and/or second axes (). Each of the first to fourth flexures () has a first end () connected to the first part () and a second end () connected to the second part (). Each of the first to fourth flexures () includes a feature () configured to increase a first compliance of that flexure () to displacement of the respective second end () towards the respective first end (). The first compliance is less than a second compliance of that flexure () to 25 displacement of the respective second end () parallel to the primary axis ().

An SMA actuator () comprising SMA wires () in which the wire arrangement is asymmetrical, allowing a greater range of motion from a rest position in a first direction than in a second direction, which may be opposite or orthogonal to the first direction. Where the directions are opposite, the angle between a principal axis and the wires providing motion in the first direction may be different from the angle between the principal axis and the wires providing motion in the second direction.

Asymmetric SMA actuator

Broadly speaking, embodiments of the present techniques provide mechanisms for electrically connecting shape memory alloy (SMA) actuator wires of an actuation device to a power or current source via at least one connection element.

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Cambridge, United Kingdom

Robert Langhorne