# US 12,216,328 B2 · Actuator assembly > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,216,328 B2 - Document ID: US12216328B2 - Status: Granted - Kind: B2 - Application number: 17/762,007 - Filed: 2020-07-06 - Published: 2022-11-10 - Granted: 2025-02-04 - Earliest claimed: 2019-07-05 - Assignees: Cambridge Mechatronics Limited - Applicants: Cambridge Mechatronics Limited - Inventors: Andrew Benjamin Simpson Brown; Robert Langhorne; James Howarth; Robin Eddington - Web page: https://patentgrep.com/patent/US12216328B2 ## CPC - F03G 7/06143: {Wires} - F03G 7/0636: {with several elements connected in parallel} - F03G 7/064: {characterised by its use} - F03G 7/0665: {controlled displacement, e.g. by using a lens positioning actuator} - G02B 7/08: adapted to co-operate with a remote control mechanism - G02B 7/09: adapted for automatic focusing or varying magnification - G02B 27/646: {compensating for small deviations, e.g. due to vibration or shake (movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68)} - G03B 3/10: Power-operated focusing - G03B 5/02: Lateral adjustment of lens - G03B 2205/0007: Movement of one or more optical elements for control of motion blur - G03B 2205/0076: using shape memory alloys - F03G: SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR (arrangements in connection with power supply in vehicles from force of nature B60K16/00; electric propulsion with power supply in vehicles from force of nature B60L8/00) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) ## Abstract An actuator assembly comprises: first (20) and second (10) parts, wherein a primary axis (P) is defined with reference to the second part; a plurality of lengths of shape-memory alloy wire (30) 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. ## Claims ### Claim 1 An actuator assembly comprising: first and second parts, wherein a primary axis 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, the three-dimensional movement including translational movement in three translational degrees of freedom; 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. ### Claim 2 (depends on 1) The actuator assembly according to claim 1, wherein the at least one position corresponds to a range of positions corresponding to at least a portion of the first part having moved by a distance of <100 μm from a central position relative to the second part. ### Claim 3 (depends on 2) The actuator assembly according to claim 2, wherein the distance is a lateral distance relative to the primary axis. ### Claim 4 (depends on 1) The actuator assembly according to claim 1, wherein the mechanism comprises: a set of one or more end stops formed on the second part; and a set of one or more resilient elements connected between the first and second parts to bias the first part such that, when the lengths of wire are unpowered, the first part moves into contact with the set of end stops. ### Claim 5 (depends on 4) The actuator assembly according to claim 4, wherein the set of end stops comprises a first set of surface regions configured to contact a first set of surface regions of the first part to control the orientation of the first part relative to the primary axis. ### Claim 6 (depends on 4) The actuator assembly according to claim 4, wherein the set of end stops comprises a second set of surface regions configured to contact a second set of surface regions of the first part to control the lateral position of at least a portion of the first part relative to the primary axis. ### Claim 7 (depends on 1) The actuator assembly according to claim 1, wherein the mechanism comprises a set of one or more resilient elements connected between the first and second parts to bias the first part towards the at least one position and/or orientation. ### Claim 8 (depends on 7) The actuator assembly according to claim 7, wherein at least one of the set of resilient elements extends in one or more directions that are at least partly perpendicular to the primary axis. ### Claim 9 (depends on 8) The actuator assembly according to claim 8, wherein the set of resilient elements comprises two or more resilient elements that are spaced from each other along the primary axis. ### Claim 10 (depends on 7) The actuator assembly according to claim 7, wherein the set of resilient elements produce a biasing force on the first part such that, for any orientation of the second part in which the primary axis is horizontal, at least a portion of the first part is a distance between 80 μm and 100 μm below a central position relative to the second part. ### Claim 11 (depends on 7) The actuator assembly according to claim 7, wherein one or more of the set of resilient elements form part of an electrical connection to a moving end of each of the lengths of shape-memory alloy wire. ### Claim 12 (depends on 1) The actuator assembly according to claim 1, wherein: the mechanism is configured to provide a non-linear biasing force that biases the first part towards the at least one position and/or orientation; the non-linear biasing force is relatively large when the first part is in the at least one position and/or orientation; and the non-linear biasing force is relatively small when the first part is in a range of positions and/or orientations associated with the three-dimensional movement of the first part. ### Claim 13 (depends on 12) The actuator assembly according to claim 12, wherein: the mechanism comprises a latch that connects the first and second parts when the first part is in the at least one position and/or orientation; and the actuator assembly further comprises control circuitry configured, before unpowering the lengths of wire, to move the first part to a position and/or orientation relative to the second part in which the non-linear biasing force is relatively large and/or in which the latch engages. ### Claim 14 (depends on 12) The actuator assembly according to claim 12, wherein the mechanism is configured to provide a non-linear biasing force that is larger than the force of gravity on the first part for any operational position and orientation of the first part relative to the second part. ### Claim 15 (depends on 12) The actuator assembly according to claim 12, wherein; the mechanism comprises a magnetic element on each of the first and second parts; at least one of the magnetic elements comprises a permanent magnet; and the magnetic elements are in proximity to each other when the first part is in the at least one position and/or orientation. ### Claim 16 (depends on 15) The actuator assembly according to claim 15, wherein the permanent magnet is a quadrupole magnet. ### Claim 17 (depends on 12) The actuator assembly according to claim 12, wherein the at least one position and/or orientation can be arrived at by a substantially translational movement of the first part along the primary axis from a central operational position and orientation of the first part relative to the second part. ### Claim 18 (depends on 17) A method of assembling an actuator assembly according to claim 17, the method comprising: selectively powering the plurality of lengths of shape-memory alloy wire to move the first part to the at least one position and/or orientation; and while holding the first part in the at least one position and/or orientation, fixing a position and/or orientation of at least a portion of the mechanism relative to first part. ### Claim 19 (depends on 12) The actuator assembly according to claim 12, wherein the first and second parts each comprise a first set of end stop surface regions configured to contact each other to guide the first part to the at least one position and/or orientation. ### Claim 20 (depends on 19) The actuator assembly according to claim 19, wherein: the first and second parts each comprise a second set of end stop surface regions configured to contact each other to define at least part of a wire protection envelope; and the first set of end stop surface regions truncate the wire protection envelope such that the at least one position and/or orientation is within the wire protection envelope. ### Claim 21 (depends on 12) The actuator assembly according to claim 12, wherein the first and second parts each comprise a set of end stop surface regions configured to contact each other to at least partly define the position of the first part along the primary axis when the first part is in the at least one position and/or orientation. ### Claim 22 (depends on 21) The actuator assembly according to claim 21, wherein the mechanism is configured to provide a non-linear biasing force that guides the first part to the at least one position and/or orientation. ### Claim 23 (depends on 1) The actuator assembly according to claim 1, wherein the mechanism comprises a latch that connects the first and second parts when the first part is in the at least one position and/or orientation. ### Claim 24 (depends on 1) The actuator assembly according to claim 1, wherein the first part has first and second portions spaced from each other along the primary axis, and the at least one position and/or orientation corresponds to a range of positions and orientations in which the first portion generally has a smaller range of positions than the second portion. ### Claim 25 (depends on 1) A camera assembly comprising an actuator assembly according to claim 1, wherein the first part comprises a camera lens and the second part comprises an image sensor and wherein the primary axis corresponds to an optical axis of an optical system. ### Claim 26 (depends on 1) A method of operating an actuator assembly according to claim 1, the method comprising: calibrating one or more offsets based on measurements of the resistance of one or more of the lengths of shape-memory alloy wire while the first part is in the at least one position and/or orientation, wherein the offsets are for adjusting one or more aspects of a control scheme such that actual positions and/or orientations of the first part relative to the second part substantially match target positions and/or orientations in respect of at least one degree of freedom. ### Claim 27 (depends on 26) The method according to claim 26, further comprising carrying out the measurements of the resistance at least partly as part of a power up procedure and before moving the first part to an operational position.