Cambridge Mechatronics Limited

Daniel John Burbridge

Stephen Matthew Bunting

Andrew Benjamin Simpson Brown

Andrew Benjamin David Brown

Joshua Carr

Robert Langhorne

James Robert Howarth

Robin Eddington

Thomas M Gregory

Oliver Hart

Peter Van Wyk

Konstantinos Pantelidis

Jason Tun

Igor Gotlibovych

Thomas Matthew Gregory

John Grayley

Stephen Kindness

Samuel Armstrong

An actuator assembly () comprises: a support structure (); a movable part () that is movable relative to the support structure; and a set of one or more actuating units (). Each actuating unit () is configured, on actuation, to apply a force on the movable part () that is substantially directed along a line in a plane perpendicular to a primary axis (z). Each actuating unit () comprises: a force-modifying mechanism () connected to one of the support structure () and the movable part (); a coupling link () connected between the force-modifying mechanism () and the other of the support structure () and the movable part (); and an SMA element () connected between the force-modifying mechanism () and the one of the support structure () and the movable part (). The SMA element () is configured to exert an input force on the force-modifying mechanism (), thereby causing the force-modifying mechanism () to apply an output force on the coupling link () and causing the coupling link () to apply an actuating force on the other of the support structure () and the movable part (). The component of the input force along the primary axis (z) has a greater magnitude than the component of the input force in any direction perpendicular to the primary axis (z).

Actuator assembly

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.

A shape memory alloy (SMA) actuator () for a camera assembly, comprising:—a support structure supporting an electronic component, wherein the electronic component is susceptible to interference caused by magnetic flux; —a moveable part moveable relative to the support structure; one or more SMA components () connected between the moveable part and the support structure, wherein the one or more SMA components are configured to, on contraction, drive movement of the movable part; —a first electrical path and a second electrical path defined between, and/or including, each of the one or more SMA components () and respective electrical terminals (a); and wherein the first and second electrical paths of each of the one or more SMA components are configured to, at least in part, extend adjacently to and in parallel with each other, and enabling the electrical current in the respective paths to flow in opposite directions, so as to minimise combined magnetic flux from the first and second electrical paths into the electronic component.

Shape memory alloy actuator

An actuation assembly comprising: a support structure; a movable element movable relative to the support structure, the movable element having a principal axis; and an actuator arrangement for driving movement of the movable element with respect to the support structure, wherein said movement includes rotational movement of the movable element about an axis which is perpendicular to said principal axis and does not pass through the centre of the movable element, and wherein said movement also includes translational movement of the movable element in a direction perpendicular to the principal axis. The actuation assembly may be used to perform optical image stabilisation or to improve the performance of a 3D sensing system.

Actuator assemblies and methods of controlling the same

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 methods for driving shape memory alloy (SMA) actuator wires in a more power-efficient manner.

Methods for controlling SMA actuators

An SMA actuation assembly comprising SMA actuator wires connected in tension between a support structure and a movable element is controlled to drive movement of the movable element with respect to the support structure by supplying drive signals to the SMA actuator wire. Target signals representing desired positions of the movable element are set, varying within a predetermined spatial envelope. Measures of resistance of the SMA actuator wires are derived and the power of the drive signals is controlled under closed loop control on the basis of the target signals and feedback signals obtained from the measures of resistance. Electrical characteristics of the SMA actuator wires are monitored and used to detect when a motion limit of the movement is reached. In response thereto, the spatial envelope is adjusted to restrict the movement to be within the detected motion limit.

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Cambridge, United Kingdom

Daniel John Burbridge