Actuator assembly

Abstract

The actuator assembly includes: a first member and a second member movable relative to each other; and at least one actuating unit, each actuating unit being configured to apply a respective actuating force to the second member upon actuation, capable of moving the second member relative to the first member, where each actuating unit comprises: a body portion; a force adjustment flexure connected between the body portion and the first component; a coupling flexure connected between the body portion and the second component; and an SMA wire connected between the body portion and the first component, where the SMA wire is arranged to apply an input force to the body portion upon actuation, thereby rotating the body portion about an effective pivot point defined by the force adjustment flexure such that an actuation force is applied to the second component via the coupling flexure, wherein an angle between i) an imaginary line between the effective pivot point P and a connection point between the SMA wire and the body portion and ii) an imaginary line between the effective pivot point P and a connection point between the coupling flexure and the body portion is greater than 135 degrees.

Description

field

[0001] This application relates to an actuator assembly having at least one actuation unit comprising a shape memory alloy (SMA) element. background

[0002] SMA actuator assemblies can be used in a variety of applications to move movable parts relative to a supporting structure.

[0003] For example, WO 2013 / 175197 A1 describes a camera in which four SMA lines are arranged to move a lens element relative to an image sensor in a plane perpendicular to the optical axis of the lens element, thereby achieving optical image stabilization (OIS). WO 2010 / 029316 A1 describes SMA actuator lines for providing OIS in a camera by tilting the camera module. WO 2011 / 104518 A1 describes an actuator assembly with eight SMA lines that enables position control of a movable element in multiple degrees of freedom.

[0004] Typically, the range of motion (also known as “stroke”) of such SMA actuator assemblies is limited by the maximum contraction of the SMA wire, and the actuation force is limited by the maximum force that the SMA wire can generate. To increase the range of motion or actuation force, longer or thicker SMA wires can be used, but this may come at the cost of increased cost, size, and / or power, which may be impractical in micro-applications.

[0005] WO 2022 / 084699 A1 discloses an actuator assembly including at least one actuation unit (containing an SMA line) that, upon actuation, moves a movable part relative to a support structure. The actuation unit can be configured to increase the stroke or actuation force and / or redirect the force applied by the SMA line. Overview

[0006] According to a first aspect of the invention, an actuator assembly is provided, comprising: a first part and a second part movable relative to each other; and at least one actuation unit, each actuation unit configured to apply a corresponding actuating force to the second part upon actuation, the actuating force enabling the second part to move relative to the first part, wherein each actuation unit comprises: a main body portion; a force-adjusting flexure connected between the main body portion and the first part; a coupling flexure connected between the main body portion and the second part; and an SMA line connected between the main body portion and the first part, wherein the SMA line is arranged to apply an input force to the main body portion upon actuation, causing the main body portion to rotate about an effective pivot point defined by the force-adjusting flexure, such that the actuating force is applied to the second part via the coupling flexure, wherein i) the angle between the effective pivot point P and the imaginary line connecting the SMA line and the main body portion and ii) the imaginary line between the effective pivot point P and the connection point between the coupling flexure and the main body portion is greater than 135 degrees.

[0007] The angle is preferably greater than 160 degrees, more preferably greater than 170 degrees, and most preferably about 180 degrees.

[0008] By arranging the SMA line and the points where the forces of the connecting flexures act on the main body on or near an imaginary line intersecting the effective pivot point, undesirable out-of-plane deformation of the force-adjusting flexures can be reduced or avoided. This makes the movement of the main body more stable, thereby ensuring more reliable operation of the actuation unit.

[0009] This applies to second-class and third-class levers as well as first-class levers. Therefore, according to a second aspect of the invention, an actuator assembly is provided, comprising: a first part and a second part movable relative to each other; and at least one actuation unit, each actuation unit configured to apply a corresponding actuating force to the second part upon actuation, the actuating force enabling the second part to move relative to the first part, wherein each actuation unit comprises: a body portion; a force-adjusting flexure connected between the body portion and the first part; a connecting flexure connected between the body portion and the second part; and an SMA line connected between the body portion and the first part, wherein the SMA line is arranged to apply an input force to the body portion upon actuation, causing the body portion to rotate about an effective pivot point defined by the force-adjusting flexure, such that the actuating force is applied to the second part via the connecting flexure, wherein (i) the effective pivot point P, (ii) the connection point between the SMA line and the body portion, and (iii) the connection point between the connecting flexure and the body portion are located on or near an imaginary line.

[0010] Further aspects of the invention are set forth in the dependent claims and in the following detailed description.

[0011] It should be understood that reference to a component “connected” between two other components means, for example, that the component is directly or indirectly connected to each of the other components. Such indirect connection can involve a connection via another component (e.g., a connector) having a fixed position relative to one of the other components. Such indirect connection can also involve a connection via one or more other components that are movable relative to the other components. For example, an SMA element can be connected to one of the first and second components via another flexure, as described, for example, in WO 2022 / 144541 (which is incorporated herein by reference). Brief description of the attached diagram

[0012] Some embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figures 1A to 1E These are schematic cross-sectional views of different variations of a camera assembly that includes an actuator assembly; Figure 2 This is a schematic perspective view of the actuator assembly; Figure 3A and Figure 3B These are perspective and plan views of the actuation unit, which forms the components of the actuator assembly, and Figure 3C This is a plan view of another such actuation unit; Figure 4 It is a schematic plan view of the arrangement of the four actuation units; Figure 5 It is a schematic perspective view of the arrangement of eight actuation units; Figure 6 This is a schematic plan view of the actuation unit based on the comparative example; Figure 7 This is a schematic plan view of the actuation unit according to the present invention; Figure 8 a to Figure 8 d indicates the action on Figure 6 and Figure 7 A schematic diagram of the forces on the actuation unit; Figure 9a This is a schematic diagram illustrating the forces acting on a comparative example of an actuating unit, which functions similarly to a third type of lever; and Figure 9b This is a schematic diagram showing the force acting on an example of an actuating unit, which functions similarly to a third type of lever. Detailed description

[0013] Camera components Figures 1A to 1EDifferent variations of the device 1, including the actuator assembly 2, are schematically shown. Device 1 is, for example, a camera assembly 1. Typically, device 1 will be incorporated into portable electronic devices such as smartphones. Therefore, miniaturization can be an important design criterion.

[0014] Figure 2 Actuator assembly 2 is schematically shown. Actuator assembly 2 includes a support structure 10 and a movable member 20. The movable member 20 is movable relative to the support structure 10. When actuator assembly 2 is included in, for example, device 1, the support structure 10 may be fixed relative to the body of device 1. However, typically, the support structure 10 does not need to be stationary and may be movable relative to device 1 or within device 1. Actuator assembly 2 includes one or more actuation units 30. Each actuation unit 30 is configured to apply an actuating force to the movable member 20, which enables the movable member 20 to move relative to the support structure 10.

[0015] The movable component 20 may be supported on the support structure 10 solely by the actuation unit 30 (i.e., suspended on the support structure 10). Alternatively, the actuator assembly 2 may include a support device 40 that supports the movable component 20 on the support structure 10. The actuation unit 30 and the support device 40 may together support the movable component 20 on the support structure 10. The support device 40 may have any suitable form that allows the movable component 20 to move relative to the support structure 10 in one or more degrees of freedom (DOF). The actuation unit 30 and / or the support device 40 may constrain (i.e., reduce or prevent) other degrees of freedom of movement of the movable component 20 relative to the support structure 10. For this purpose, the support device 40 may include, for example, one or more of the following support elements: rolling support elements (such as ball bearings), flexural support elements (i.e., arrangements of flexural elements or other elastic elements guiding movement), or sliding (i.e., sliding contact) support elements.

[0016] The main axis P may be defined with reference to actuator assembly 2 and / or support structure 10. The main axis P may extend through actuator assembly 2, for example, through the center of actuator assembly 2. In some examples, actuator assembly 2, support structure 10, and / or movable member 20 extend primarily in a direction perpendicular to the main axis P. In other words, the extent of actuator assembly 2, support structure 10, and / or movable member 20 along the main axis P is less than the extent of actuator assembly 2, support structure 10, and / or movable member 20 along any direction perpendicular to the main axis P. The main axis P may be the longitudinal axis of actuator assembly 2 and / or support structure 10. Alternatively or additionally, support structure 10 and / or movable member 20 may include planar members extending perpendicular to the main axis P. Alternatively or additionally, in examples where device 1 includes an optical element (such as lens assembly 3) having an optical axis or an imaging element (such as imager sensor 4) having an imaging axis, when movable member 20 is in a central position or orientation (e.g., see...), Figure 1A The main axis P can be parallel to such an axis and / or can coincide with such an axis.

[0017] Typically, the movable component 20 can be movable relative to the supporting structure 10 with up to six degrees of freedom (DOF). In the context of describing the degrees of freedom of movement, the principal axis P can also be referred to as the z-axis, and the other two axes perpendicular to the principal axis P and perpendicular to each other can be referred to as the x-axis and y-axis. The movable component 20 can be movable relative to the supporting structure 10 in all or any subset of the following degrees of freedom (including only one degree of freedom): • Tx and Ty: Translational motion in the Xy plane. In other words, the movable part 20 can move independently along the x-axis and y-axis. The movable part 20 can move to any position in the xy plane within its range of motion. Instead of this planar movement, the movable part 20 can be linearly movable, for example, along the x-axis or y-axis.

[0018] • Rx and Ry: Rotational movement (or simply rotation or tilt) about the x-axis and y-axis. In other words, the movable part 20 can rotate about any line perpendicular to the principal axis P. The movable part 20 can rotate to any rotational position (i.e., to any orientation) within its range of motion. Instead of this dual-axis rotation, the movable part 20 can rotate about a single axis (e.g., about the x-axis or y-axis).

[0019] •Tz: Translational movement along the z-axis. The movable part 20 can move to any translational position along the z-axis within its range of motion.

[0020] •Rz: Rotational movement (or simply rotation) about the z-axis. The movable part 20 can rotate to any rotational position (i.e., rotate to any orientation) within its range of motion.

[0021] In some examples, the movable component 20 may be supported, for example, by a support device 40 to allow translational movement (Tx, Ty) in the xy plane and / or rotational movement (Rz) about the z-axis. Translational movement (Tz) along the z-axis and rotational movement (Rx, Ry) about the x and y axes may be constrained. For example, such support may be provided by a support device 40 having a suitable arrangement of ball bearings or sliding bearings that generate a supporting force in the +z direction and a biasing device that generates a biasing force in the -z direction. Examples of actuator assemblies with such support devices are disclosed in WO 2013 / 175197 A1 and WO2017 / 072525 A1, each of which is incorporated herein by reference.

[0022] In some examples, the movable component 20 can be supported to allow tilting (Rx, Ry) about the x-axis and y-axis and optionally rotation (Rz) about the z-axis. Other degrees of freedom of movement (i.e., Tx, Ty, Tz, Rz or Tx, Ty, Tz) can be constrained. This support can be provided by a support device 40 (e.g., in the form of a gimbal). An example of such a support device 40 is disclosed in WO 2021 / 209770 A1, which is incorporated herein by reference. Alternatively, this support can be provided solely by an actuation unit 30, similar to WO 2011 / 104518 A1, which discloses an actuator assembly having eight SMA lines connecting the support structure 10 and the movable component 20. WO 2011 / 104518 A1 is incorporated herein by reference.

[0023] In some examples, the movable component 20 can be supported to allow three-dimensional translational movement (Tx, Ty, Tz), while rotational movement (Rx, Ry, Rz) can be constrained. This support can be provided by a support device 40 (e.g., in the form of nested linear supports). An example of such a support device 40 is disclosed in WO 2021 / 209769 A1, which is incorporated herein by reference. Alternatively, similar to WO 2011 / 104518 A1, this support can be provided solely by the actuation unit 30.

[0024] Alternatively or additionally, the movable component 20 can move on other DOFs. The movable component 20 can move on a DOF as a combination of any two or more of Tx, Ty, Tz, Rx, Ry, and Rz. For example, the movable component 20 can move along a helical path about the z-axis (i.e., helically), and thus simultaneously move along and rotate about the z-axis. In other words, Tz and Rz movements can be combined. An example of such a helical actuator assembly is disclosed in WO 2019 / 243849A1, which is incorporated herein by reference.

[0025] Actuation unit 30 is connected between support structure 10 and movable member 20. Actuation unit 30 is arranged to apply actuating force F between movable member 20 and support structure 10 (see example...). Figure 4 and Figure 5 Selectively changing the actuating force F can move the movable part 20 relative to the support structure 10, for example, within the degrees of freedom allowed by the support device 40. Therefore, the actuating unit 30 is able to drive the movement of the movable part 20 relative to the support structure 10.

[0026] The support device 40 can move the movable part 20 in a direction different from the direction of the actuating force F. In a simple example in this respect, one component of each actuating force F causes the movement of the movable part 20, and another component of each actuating force F counteracts the supporting force generated by the support device 40.

[0027] Camera assembly 1 also includes lens assembly 3 and image sensor 4. Lens assembly 3 includes one or more lenses configured to focus an image onto image sensor 4. Lens assembly 3 defines an optical axis O. Lens assembly 3 may include a lens holder (e.g., in the form of a cylindrical body) supporting one or more lenses. Image sensor 4 captures images and can be of any suitable type, such as a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) device. Camera assembly 1 can be a compact camera assembly in which each lens has a diameter of 20 mm or less, such as 12 mm or less.

[0028] exist Figure 1A In the "sensor-shift" variant of the camera assembly 1 shown, the movable component 20 includes the image sensor 4. The lens assembly 3 may be fixed relative to the support structure 10, or may be movable relative to the support structure 10 along the optical axis O (as described below).

[0029] exist Figure 1BIn the illustrated (“lens-shift”) variant, the image sensor 4 is fixed relative to the support structure 10, and the movable part 20 includes a lens assembly 3. As described below, the lens assembly 3 can be movable relative to the movable part 20 along the optical axis O.

[0030] In both variations, the actuator assembly 2 is configured to move the lens assembly 3 relative to the image sensor 4 in any direction within a plane perpendicular to the main axis P and therefore perpendicular to the optical axis O. This movement has the effect of moving the image onto the image sensor 4 and enables optical image stabilization (OIS) in the camera assembly 1. In the sensor-shifting variation, the movable part 20 can also be rotatable about the main axis P so as to compensate for roll as well.

[0031] exist Figure 1C In the illustrated (“module-tilt”) variant, the movable part 20 includes both the lens assembly 3 and the image sensor 4. Furthermore, as described below, the lens assembly 3 can move relative to the movable part 20 along the optical axis O. The actuator assembly 2 is configured to tilt the movable part 20 about two axes perpendicular to the main axis P and perpendicular to each other, and optionally to rotate the movable part 20 about the main axis P, enabling OIS to be implemented in the camera assembly 1.

[0032] exist Figure 1D In the illustrated ("autofocus" or "zoom") variant, the movable part 20 includes a lens assembly 3, and the actuator assembly 2 moves the movable part 20 relative to the support structure 10 along the optical axis O. This movement has the effect of adjusting the focus of the image on the image sensor 4 or providing a zoom function. Therefore, autofocus (AF) or zoom function can be implemented in the camera assembly 1.

[0033] In some examples (not shown), camera component 1 may include features for providing, for example, Figures 1A to 1C The first actuator assembly of the OIS shown, and the one for providing such Figure 1D The second actuator assembly for AF or zoom is shown. One or both of the first and second actuator assemblies may correspond to actuator assembly 2 as described herein. One of the first and second actuator assemblies may be another type of SMA actuator assembly or may be a non-SMA actuator assembly, such as a voice-coil motor (VCM) actuator assembly. As will be understood, in lens shift and module tilt variants, the support structure 10 of the second actuator assembly 2 is fixed to (or corresponds to) the movable part 20 of the first actuator assembly 2.

[0034] exist Figure 1EIn the illustrated ("AF+OIS") variant, the movable part 20 includes a lens assembly 3, and the actuator assembly 2 generates a three-dimensional translational movement of the movable part 20 relative to the support structure 10, making it possible to achieve both AF and OIS using a single actuator assembly 2.

[0035] Other variations are also possible. For example, in an autofocus or AF+OIS variation, the movable part 20 may include the image sensor 4 but not the lens assembly 3. The camera assembly 1 may include a combination of the features described above, such as (a) lens shift and sensor shift, (b) module tilt and lens shift or sensor shift and autofocus, or (c) module tilt and AF+OIS.

[0036] Camera assembly 1 also includes a controller 8. The controller 8 may be implemented as an integrated circuit (IC) chip. The controller 8 generates a drive signal for the actuation unit 30 (particularly for the SMA line 34 forming the components of the actuation unit 30). The SMA material has the property of undergoing a solid-state phase transition upon heating, causing the SMA material to contract. Therefore, applying a drive signal to the SMA line 34, thereby heating the SMA line 34 by allowing current to flow, will cause the SMA line 34 to contract and thus actuate the actuation unit 30 to drive relative movement of the movable component 20. The drive signal is selected to drive the relative movement of the movable component 20 in a desired manner, for example, to achieve OIS by stabilizing the image sensed by the image sensor 4, or to achieve AF by adjusting the focus of the image sensed by the image sensor 4. The controller 8 provides the generated drive signal to the SMA line 34.

[0037] Optionally, camera assembly 1 also includes a motion sensor (not shown), which may include a 3-axis gyroscope and a 3-axis accelerometer. The motion sensor can generate signals representing the motion of camera assembly 1 (specifically, vibration or "shake"), which can be processed to generate signals representing the desired movement of movable part 20, thereby compensating for such shake. Controller 8 receives such signals and can generate drive signals for SMA line 34 to achieve OIS.

[0038] Although the actuator assembly 2 is described in conjunction with the camera assembly 1, it should be understood that the actuator assembly 2 can be used in any device in which the movable part 20 is expected to move relative to the support structure 10, for example, to provide haptic feedback in a haptic feedback device or to move a projector or display in an augmented reality (AR) or virtual reality (VR) device.

[0039] Actuation unit Figure 3A A perspective view of an example of the actuation unit 30 is shown. Figure 3B A portion of the actuation unit 30 is shown in a plan view.

[0040] exist Figure 3A and Figure 3B A single actuation unit 30 is shown, but it should be understood that the actuator assembly 2 typically has multiple actuation units 30, each of which may include a reference. Figure 3A and Figure 3B The same components described.

[0041] The actuation unit 30 includes a main body portion 31 to which several other components of the actuation unit 30 are connected, as described below. Typically, the main body portion 31 is relatively rigid compared to the other components of the actuation unit and does not deform significantly when the actuation unit 30 is actuated. In some examples, the main body portion 31 is not a separate component of the actuation unit 30. For example, the main body portion 31 may be defined as part of one of the other components of the actuation unit 30, or simply as a connection point between the other components of the actuation unit 30.

[0042] The actuation unit 30 also includes a force-adjusting flexure 32. The force-adjusting flexure 32 is connected between the main body portion 31 and the support structure 10. One end of the force-adjusting flexure 32 is connected to the main body portion 31. The other end of the force-adjusting flexure 32 is connected to the support structure 10, for example, via a foot portion 36. The foot portion 36 is fixed relative to the support structure 10. The force-adjusting flexure 32 allows the main body portion 31 to pivot relative to the support structure 10 about an effective pivot point P. Although the effective pivot point P is at... Figure 3B The pivot point P is shown as being positioned in the middle of the force-adjusting flexure 32, but the effective pivot point P can have a different location and does not need to be located on the force-adjusting flexure 32. This pivoting movement of the main body 31 relative to the support structure 10 initially occurs in a direction substantially perpendicular to the force-adjusting flexure 32.

[0043] The actuation unit 30 also includes an SMA element 34. In this example, the SMA element 34 is an SMA wire 34. The SMA wire 34 connects the main body portion 31 and the support structure 10. One end of the SMA wire 34 is connected to the support structure 10, for example, via a crimp 15. The other end of the SMA wire 34 is connected to the main body portion 31, for example, via a crimp 35.

[0044] The actuation unit 30 also includes a connecting link 33. In this example, the connecting link 33 is a connecting flexure 33. The connecting flexure 33 connects between the main body portion 31 and the movable member 20. One end of the connecting flexure 33 is connected to the main body portion 31. The other end of the connecting flexure 33 is connected to the movable member 20. The connecting link 33 transmits or transfers the actuating force F from the main body portion 31 to the movable member 20. The connecting link 33 is flexible (i.e., deformable) in a direction perpendicular to the actuating force F (or multiple directions). This allows the movable member 20 to move in directions other than those of the connecting flexure 33 and the actuating force F. This may be necessary, for example, in situations where different actuation units 30 cause the movable member 20 to move in different directions.

[0045] In this example, the main body 31, the force-adjusting flexure 32, the connecting flexure 33, and the foot portion 36 are integrally formed, for example, from a single sheet of material (such as metal). In other examples, one or more of these features (if present) may be formed from different parts or materials.

[0046] SMA line 34 is arranged to apply an input force Fi to the main body portion 31 during contraction. The input force Fi acts parallel to the length of SMA line 34. Force-adjusting flexure 32 and the main body portion 31 are arranged to adjust the input force Fi to generate an actuating force F, which is transmitted from the main body portion 31 to the movable member 20 via connecting flexure 33. Specifically, the input force Fi deforms the force-adjusting flexure 32, thereby pivoting the main body portion 31 about an effective pivot point P. In short, the force-adjusting flexure 32 and the main body portion 31 act like levers. The force-adjusting flexure 32 and the main body portion 31 can adjust the direction and / or magnitude of the input force Fi to generate the actuating force F.

[0047] exist Figure 3A and Figure 3B In the example shown, the connecting flexure 33 is at an angle of approximately 90° relative to the SMA line 34. Furthermore, in this example, the force-adjusting flexure 32 is arranged at an angle α of approximately 30° relative to the SMA line 34, and the force-adjusting flexure 32 is in a tensile state when the SMA line 34 contracts. Therefore, as the SMA line 34 contracts and the resulting force-adjusting flexure 32 deforms, the main body portion 31 initially moves at an angle of approximately 60° (90°-α) relative to the length of the SMA line 34. Thus, it should be understood that in this example, the force is reduced and the stroke is amplified, while the direction of force / movement is changed by approximately 90°.

[0048] More generally, the change in the direction of the force depends on the angle between the SMA line 34 and the connecting flexure 33. Also more generally, the change in the magnitude of the force depends on the ratio of i) the distance Ds from the effective pivot point P to the line containing the SMA line 34 and ii) the distance Dc from the effective pivot point P to the line containing the connecting flexure 33. Specifically, F / Fi is proportional to Ds / Dc. If the line containing the SMA line 34 is closer to the effective pivot point P than the line containing the connecting flexure 33, the input force Fi is reduced. Simultaneously, the movement of the movable member 20 is amplified, i.e., increased relative to the change in the length of the SMA line 34. Alternatively, if the line containing the SMA line 34 is farther from the effective pivot point P than the line containing the connecting flexure 33, the input force Fi is amplified. Simultaneously, the movement of the movable member 20 is reduced, i.e., decreased relative to the change in the length of the SMA line 34. Therefore, the actuation unit 30 can be configured to amplify the movement or force caused by the contraction of the SMA line 34. The actuation unit 30 can also be configured to change the direction of the input force Fi. In some examples, the actuation unit 30 is configured to change the direction of the input force Fi without changing the magnitude of the force or movement.

[0049] The ratio Ds / Dc depends on the position of the SMA line 34 connected to the end of the main body 31 and the position of the connecting flexure 33 connected to the end of the main body 31. As an example, this can be achieved by further connecting the connecting flexure 33 to... Figure 3B The distance Dc is increased by moving the left side of the main body 31 shown, thereby decreasing Ds / Dc and thus increasing the stroke amplification. The ratio Ds / Dc also depends on the orientation of the SMA line 34 and the orientation of the connecting flexure 33. Such orientation can be defined with reference to the force-adjusting flexure 32 (as above) or any suitable reference line. As an example, it can be achieved by making... Figure 3B The SMA line 34 shown is angled so that Figure 3B The SMA line 34 shown extends closer to the effective pivot point P to reduce the distance Ds, thereby reducing Ds / Dc and thus increasing the stroke amplification. In summary, the amount by which the force-adjusting flexure 32 amplifies or reduces the force / stroke of the SMA line 34 can be customized in the following ways: • Adjust the orientation of SMA line 34 (and thus adjust the input force Fi). • Adjust the position of the connection point between the SMA line 34 and the main body 31 (and thus adjust the position of the input force Fi acting on the main body 31). • Adjust the orientation of the connecting flexure 33 (and thus adjust the actuating force F); and / or • Adjust the position of the connection point between the connecting flexure 33 and the main body 31 (and thus adjust the position where the actuating force F is applied to the main body 31).

[0050] In some examples, at least one actuation unit 30 (preferably each actuation unit 30) is configured such that the force-adjusting flexure 32 and the main body portion 31 amplify the amount of contraction of the SMA line 34. For example, such amplification factor can be greater than 1.5, preferably greater than 2, and more preferably greater than 3. Therefore, in Figure 3A and Figure 3B In the example shown, the angle α between the SMA line 34 and the force-adjusting flexure 32 can be in the range of 0 to 45 degrees, preferably in the range of 13 to 40 degrees. However, typically, the angle α can have other values, and the connection point between the SMA line 34 and / or the connecting flexure 33 and the body portion 31 can be adjusted to achieve the desired amplification.

[0051] As mentioned above, in Figure 3A and Figure 3B In the example shown, the connecting flexure 33 is at an angle of approximately 90 degrees relative to the SMA line 34. This allows the actuating unit 30 to fold compactly around the corner of the movable member 20. The angle between the connecting flexure 33 and the SMA line 34 can be in the range of 70 to 110 degrees, preferably in the range of 80 to 100 degrees. However, typically, the angle between the connecting flexure 33 and the SMA line 34 can be outside these ranges.

[0052] For example, in Figure 3C In the actuation unit 30 shown, the force-adjusting flexure 32, the connecting flexure 33, and the SMA line 34 are substantially parallel to each other.

[0053] In the example above, the actuation unit 30 is arranged in a plane. Specifically, at least when the actuator assembly 2 is in its initial configuration, the SMA line 34, the connecting flexure 33, and the force-adjusting flexure 32 are arranged to extend substantially in a common plane. This allows for a compact configuration of the actuation unit 30. When implemented as a plate, the main body portion 31 can also be arranged to extend in this plane. However, typically, the components of the actuation unit 30 are not necessarily arranged in a common plane. For example, the SMA line 34 and / or the connecting flexure 33 may be angled relative to this plane.

[0054] In the example above, the force-adjusting deflector 32 is placed in a tensile state when the SMA line 34 contracts. This reduces the risk of buckling of the force-adjusting deflector 32, thereby reducing the risk of damage to the actuator assembly 2 and making the actuator assembly 2 more reliable. However, the force-adjusting deflector 32 can alternatively be arranged to be placed in a compressive state when the SMA line 34 contracts. (See reference...) Figure 3BFor example, the force-adjusting flexure 32 can extend downward and to the right from the connection point between the main body 31 and the force-adjusting flexure 32, and is thus placed in a compressed state when the SMA line 34 contracts. An arrangement in which the force-adjusting flexure 32 is placed in a compressed state is disclosed in WO 2022 / 084699 A1, which is incorporated herein by reference.

[0055] In the example above, the force-adjusting flexure 32 and the SMA line 34 are connected to the support structure 10 at one end, and the connecting flexure 33 is connected to the movable member 20 at one end. Typically, this arrangement can also be reversed, where the force-adjusting flexure 32 and the SMA line 34 are connected to the movable member 20 at one end, and the connecting flexure 33 is connected to the support structure 10 at one end.

[0056] In the above example, the actuation unit 30 includes a connecting link 33 in the form of a connecting flexure 33. The purpose of the connecting link 33 is to allow the movable part 20 to move in a direction perpendicular to the actuating force F. However, typically, the actuation unit 30 does not need to include a connecting link 33 (e.g., in examples where the movable part 20 does not move in a direction perpendicular to the actuating force F). Furthermore, the connecting link 33 can be implemented as a component other than the connecting flexure 33, for example, as a ball bearing or sliding support configured to transmit the actuating force F to the movable part 20 while allowing the movable part 20 to move in a direction perpendicular to the actuating force F. Such an alternative example of the connecting link 33 is disclosed in WO 2022 / 084699 A1. The connecting link 33 may (or may not) be formed of an SMA line, which may (or may not) be integral with the SMA line 34 and may (or may not) be driven together with the SMA line 34.

[0057] In addition, instead of the force-adjusting flexure 32, the actuator assembly may include different types of force-adjusting elements configured to allow the main body portion 31 to move relative to the support structure 10 as described above. Such force-adjusting elements may include, for example, a rigid member, one end of which is connected to the support structure 10 via a suitable pivoting connection (e.g., a pin joint), and the other end of which is connected to the main body portion 31.

[0058] Arrangement of the four actuation units Figure 4 A schematic plan view of an example actuator assembly 2 is shown, illustrating the arrangement of the actuation units 30. In this example, actuator assembly 2 includes a total of four actuation units 30. The four actuation units 30 can apply an actuating force F between the movable part 20 and the support structure 10. The actuating force F is applied to the movable part 20 relative to the support structure 10.

[0059] Figure 4 The arrangement of the actuation unit 30 can be used, for example, in an example where the movable part 20 can move relative to the support structure 10 in a plane of movement. Therefore, Tx, Ty, and optionally Rz movements of the movable part 20 are permitted.

[0060] Figure 4 The four actuation units 30 are arranged such that an actuating force F can be applied to move the movable part 20 relative to the support structure 10 to any position within its range of motion. The range of motion can be within a plane of motion perpendicular to the main axis P.

[0061] Specifically, the two actuation units 30 (e.g., Figure 4 The top and bottom actuation units are arranged to apply an actuating force F in two opposite directions parallel to the first axis (e.g., the x-axis). The other two actuation units (e.g., Figure 4 The left and right actuating units 30 are arranged to apply an actuating force F in opposite directions to a second axis (e.g., the y-axis) that is parallel to and perpendicular to the first axis. By appropriately changing the difference in actuation amount between the opposing actuating units 30, the movable part 20 can thus move independently along the first and second axes. The opposing actuating forces F are not collinear, but offset from each other in a direction perpendicular to the actuating forces F. Setting the opposing actuating units 30 allows control of the tension in the SMA lines 30 of the respective actuating units 30, thereby allowing for more accurate and reliable positioning of the movable part 20 compared to the case where the actuating units 30 are not opposite each other.

[0062] In some examples, the actuating forces F are not collinear. This allows the arrangement of the actuating units 30 to translate the movable component 20 without applying any net torque to it. Therefore, the movable component 20 can translate within the plane of motion without rotating within it. Typically, the arrangement of the actuating units 30 allows for precise control of the torque or moment of the movable component 20 about the main axis P. Therefore, the actuating units 30 can cause the movable component 20 to rotate (or not rotate) relative to the supporting structure about the main axis P.

[0063] Specifically, the two actuation units 30 (e.g., Figure 4 The top and bottom actuation units are arranged to apply an actuating force F to generate torque or moment in a first direction (e.g., clockwise) between the movable part 20 and the support structure 2 about the main axis P. Two other actuation units 30 (e.g., Figure 4The left and right actuating units 30 are arranged to apply an actuating force F to generate torque or moment between the movable part 20 and the support structure 2 in a second opposite direction (e.g., counterclockwise) about the main axis P. This allows the movable part 20 to be rotated by simultaneously increasing or decreasing the tension of the SMA wire in either of the two actuating units 30.

[0064] As shown in the figure, two actuation units 30 can be arranged to apply an actuating force F at the corner of the actuator assembly 2. Two other actuation units 30 can be arranged to apply an actuating force F at another opposite corner of the actuator assembly 2. The actuator assembly 2, particularly the movable member 20 and / or the support structure 10, can have a square or rectangular footprint. Each actuation unit 30 can be disposed on one of the four sides of the actuator assembly 2. In particular, each actuation unit 30 can be bent around the corner of the movable member 20 such that the SMA line 34 and the connecting flexure 33 of each actuation unit 30 extend along the adjacent edges of the movable member 20. Therefore, the actuation unit 30 can, for example, be as shown in... Figure 3A and Figure 3B The four SMA lines 32 of the four actuation units 32 can extend along the four different edges of the movable part 20.

[0065] The arrangement of the actuating force F applied between the movable part 20 and the support structure 10 corresponds to the arrangement of the SMA line 30 described in WO2013 / 175197A1, which is incorporated herein by reference.

[0066] In this example, the actuating force F is perpendicular to the main axis P and may be parallel to the plane of movement. However, typically, the actuating force F may be angular relative to the plane of movement. Therefore, the actuating force F may have a component along the main axis P. This component along the main axis P can be resisted by the support device 40, for example, to provide the movable member 20 with movement within the degrees of freedom allowed by the support device 40. In some examples, it may even be desirable for the actuating force F to have a component parallel to the main axis P, for example, to apply a load to a sliding or rolling support arranged between the movable member 20 and the support structure 10.

[0067] Although, for illustrative purposes, the arrangement of the actuating unit 30 is described as moving the movable component 20 in a plane of motion (e.g., translating along the x-axis and y-axis, or rotating about the main axis P), in other examples, the movable component 20 may move in different ways. For example, the same arrangement of the actuating force F can be used to tilt the movable component 20 relative to the support structure 10 about an axis perpendicular to the main axis P due to appropriate movement constraints provided by the support device 40. For example, the support device 40 may include a plurality of flexures for guiding the tilting of the movable component 20 about an axis perpendicular to the main axis P. An example of such a support device 40 is described in WO2022 / 029441 A1, which is incorporated herein by reference.

[0068] Although actuator assembly 2 is described herein in the context of four actuation units 30, actuator assembly 2 may typically include fewer actuation units 30. For example, actuator assembly 2 may include two actuation units 30, such as... Figure 4 The two actuation units 30 are depicted in the upper left corner. The force applied to the movable part 20 by the two actuation units 30 can be counteracted by the biasing force of one or more elastic elements (such as springs). (See reference) Figure 4 The two actuation units 30 in the lower right corner can be replaced, for example, by springs that apply a biasing force along the corresponding depicted arrows.

[0069] Arrangement of eight actuation units Figure 5 a to Figure 5 c schematically shows a perspective view of different versions of the actuator assembly 2 having a total of eight actuation units 30. The eight actuation units 30 can apply an actuating force F between the movable part 20 and the support structure 10. The actuating force F is applied to the movable part 20 relative to the support structure 10.

[0070] Figure 5 The arrangement of the actuation unit 30 can, for example, be used in which the movable part 20 can be relative to the support structure 10 with three translational degrees of freedom (Tx, Ty, Tz) (see...). Figure 1E ) or with two or three rotational degrees of freedom (Rx, Ry or Rx, Ry, Rz) (see Figure 1C (Example of movement)

[0071] The eight actuation units 30 can be arranged such that their actuation force F is oriented or arranged in a manner equivalent to the orientation or arrangement of the force applied by the eight SMA lines in the actuator assembly disclosed in WO 2011 / 104518 A1.

[0072] More specifically, the actuating forces F (e.g., when visualized as a vector at a specific location in space) are arranged around the principal axis P on each of the four sides (i.e., the first side, the second side, the third side, and the fourth side). When viewed perpendicularly from the principal axis P, the two actuating forces F on each side are tilted in opposite directions relative to the plane perpendicular to the principal axis P. The four sides on which the actuating forces F are arranged extend in a loop around the principal axis P. In this example, adjacent sides are perpendicular to each other, and when viewed along the principal axis P, the sides form a square; however, alternatively, the sides can take different shapes, such as quadrilateral shapes. In this example, the actuating forces F are parallel to the outer surface of the square envelope of the movable part 20, but this is not required.

[0073] Four actuating forces F, including one actuating force F on each side, form a "first" group with a component in one direction ("upward" or +z), and another four actuating forces F form a "second" group with a component in the opposite direction ("downward" or -z). In this document, "upward" and "downward" refer to opposite directions along the principal axis P.

[0074] These actuating forces F are arranged symmetrically, with the same size and tilt angle, such that the first group of actuating forces F and the second group of actuating forces F are each arranged with two-fold rotational symmetry about the principal axis P.

[0075] As a result of this symmetrical arrangement, different combinations of actuation forces F can drive the movement of the movable part 20 with multiple degrees of freedom, as shown below.

[0076] When the first set of actuating forces F are generated together, they drive the movement upward (+z), while when the second set of actuating forces F are generated together, they drive the movement downward (-z).

[0077] Within each group, when adjacent pairs of actuation forces F are generated differently, they drive tilting (Rx or Ry) about a transverse axis perpendicular to the principal axis P. Tilting in any arbitrary direction can be achieved as a linear combination of tilts about the two transverse axes.

[0078] A set of four actuating forces F, including two actuating forces F from each group, when generated together, drive movement (Tx or Ty) along a transverse axis perpendicular to the principal axis P. Movement in any direction perpendicular to the principal axis z can be realized as a linear combination of movements along the two transverse axes.

[0079] Actuator assembly 2 may have other specific arrangements of actuation unit 30, such as Figure 5The arrangement shown in the figure. For example, strict symmetry is not required. Furthermore, instead of having an up-pulling actuating unit 30 and a down-pulling actuating unit 30 on each of two opposite sides (e.g., the first side and the third side), two up-pulling actuating units 30 can be present on each of two opposite sides (e.g., the first side and the third side), and two down-pulling actuating units 30 can be present on the other two sides (e.g., the second side and the fourth side).

[0080] Other variations It will be understood that many other variations of the above example may exist.

[0081] For example, the actuator assembly may include actuation units of a different type than those described above. Examples of such actuation units include folded SMA wire devices as disclosed in WO 2021 / 111131 A1, V-shaped SMA wires with deformable connectors as disclosed in WO 2013 / 121225 A1, scissor-type push devices as disclosed in WO 2021 / 156458 A1, two-stage devices as disclosed in WO 2021 / 111181A1, or simply SMA wires connected between the support structure 10 and the movable part 20. To the maximum extent permitted by law, each of the documents mentioned in the foregoing sentences is incorporated herein by reference. The actuator assembly may have any number of actuation units of different types, and may have any suitable number of actuation units of each type.

[0082] Improved stability of the main body Figure 6 An actuation unit 30 according to a comparative example of the invention is schematically shown. As shown, the SMA line 34 and the connecting flexure 33 are both connected to the main body portion 31 at a point following the effective pivot point P defined by the force-adjusting flexure 32. An angle of less than 135 degrees is formed between line 34a between the effective pivot point P and the point where the SMA line 34 connects to the main body portion 31, and between line 33a between the effective pivot point P and the point where the connecting flexure connects to the main body portion 31. As a result, the input force Fi and the actuating force F can apply torque about the effective pivot point P about an axis in the plane of the actuation unit 30. Reference Figure 6 As a result, the force-adjusting flexure 34 may undesirably bend out of plane. This undesirable out-of-plane deformation may lead to high stress in the force-adjusting flexure 34, posing a risk of fatigue and failure, as well as reducing the performance of the actuation unit 30.

[0083] The inventors have identified the problem of potential undesirable out-of-plane deformation of the actuation unit 30. One solution to this problem is to provide supports or other constraints to limit the movement of the main body portion 31 out of the plane. However, this approach may result in additional components and costs for the actuation unit 30, and additional friction, thus reducing the performance of the actuation unit 30. The present invention aims to solve the problem of undesirable out-of-plane deformation without introducing additional components to constrain out-of-plane movement. According to the invention, the main body portion 31 is designed such that any torque on the main body portion 31 caused by the input force Fi and the actuation force F results in reduced or avoided out-of-plane deformation.

[0084] Figure 7 An embodiment of the actuation unit 30 according to the invention is schematically depicted. The effective pivot point P, the point where the SMA line 34 connects to the main body portion 31, and the point where the connecting flexure 33 connects to the main body portion 31 are located on a straight line. Thus, the forces in the SMA line 34 and the connecting flexure 33 do not exert out-of-plane torque on the main body portion 31 around the effective pivot point P. Therefore, undesirable out-of-plane deformation of the force-adjusting flexure can be avoided.

[0085] exist Figure 7 In the embodiments, the angle α between i) line 34a between the effective pivot point P and the point where the SMA line 34 connects to the main body portion 31, and ii) line 33a between the effective pivot point P and the point where the connecting flexure connects to the main body portion 31, is 180 degrees. This is particularly preferred because it allows for minimizing undesirable out-of-plane torque. The benefits of the invention are also realized when the angle α is close to 180 degrees. In particular, the angle α is preferably greater than 135 degrees, more preferably greater than 160 degrees, and more preferably greater than 170 degrees. Therefore, with Figure 6 Compared to the comparative example, undesirable out-of-plane deformation of the force-adjustable flexure 32 can be reduced. An angle α closer to 180 degrees results in less undesirable out-of-plane deformation.

[0086] Figure 7 The main body 31 of the actuation unit 30 is shaped to position the SMA line 34 connected to the main body 31 along a line intersecting the effective pivot point, and the connecting flexure 33 connected to the main body 31 at the same point. Figure 7 In the middle, the main body 31 includes two arms extending from the connection point to the force-adjusting flexure. The first arm is arranged between the force-adjusting flexure 31 and the SMA line 34. The second arm is arranged between the force-adjusting flexure 31 and the connecting flexure 33. The first and second arms extend from the connection with the force-adjusting flexure towards the effective pivot point P, that is, towards the connection point between the force-adjusting flexure and the support structure 10.

[0087] Figure 8 a to Figure 8 d further illustrates the technical benefits of the invention. The accompanying drawings show lines passing through the force-adjusting deflector 34 and the connecting deflector 33 relative to the effective pivot point P defined by the force-adjusting deflector 32. Figure 8 a shows the state when it is in the center position (i.e., when it is not deformed by SMA line 34). Figure 7 The actuation unit 30 has this kind of line. Figure 8 b shows the use of deformation through SMA line 34. Figure 7 The actuation unit 30 has this kind of line. Figure 8 c shows according to Figure 6 The comparative example is the actuation unit 30 when it is in the center position (i.e., when it is not deformed by the SMA line 34). Figure 8 d shows according to Figure 6 The comparative example is the actuation unit 30 when it is deformed by the SMA line 34.

[0088] like Figure 8 c and Figure 8 As shown in d, in the comparative example, the angle between the SMA line 34 and the connecting flexure 33 is relatively large. This may result in greater transmission, i.e., a larger stroke amplification. However, as mentioned above, the stability of the actuation unit 30 may be subject to undesirable effects. The distances Ds and Dt can vary relatively greatly, resulting in a relatively large difference in the amplification coefficient between the center position and the edge position of the main body 31.

[0089] In comparison, Figure 8 a and Figure 8 b shows the relatively small changes in distances Ds and Dt of the actuation unit 30 according to the invention. This ensures that the amplification amounts between the center and edge positions of the main body 31 remain relatively similar. Therefore, the control of the actuation unit 30 becomes easier.

[0090] The examples above involve actuation units that function like a first-class lever. Similar principles apply to actuation units that function like a second-class lever and (often more useful, stroke-amplified) actuation units.

[0091] Figure 9a A comparative example of an actuation unit 30 that functions like a third type of lever is shown. Specifically, Figure 9a The positions of the effective pivot point P, the connection point Q between the SMA element 34 and the main body (not shown), and the connection point R between the connecting flexure 33 and the main body are shown. It can be seen that the line L passing through connection points R and Q passes behind the effective pivot point P, allowing the force-adjustable flexure (not shown) to undergo undesirable out-of-plane deformation, as shown in the reference above. Figure 6 As stated above. In contrast, in Figure 9bIn the actuation unit 30 shown, the equivalent line L passes through the effective pivot point P, and in such an example, undesirable out-of-plane deformation of the force-adjustable flexure can be avoided.

[0092] SMA The aforementioned SMA actuator assembly includes at least one SMA element. The term "shape memory alloy (SMA) element" can refer to any element that includes an SMA. An SMA element can be described as an SMA line. An SMA element can have any shape suitable for the purposes described herein. An SMA element can be elongated and can have a circular cross-section or any other cross-section shape. The cross-section can vary along the length of the SMA element. An SMA element can have relatively complex shapes, such as a helical spring shape. It is also possible that the length of the SMA element (as defined in any way) can be similar to one or more of the other dimensions of the SMA element. An SMA element can be sheet-like, and such sheet can be planar or non-planar. An SMA element can be flexible, or in other words, a flexible SMA element. In some examples, when connected in a straight line between two members, the SMA element can only apply tension that forces the two members together. In other examples, the SMA element can bend around a member, and the SMA element can apply a force to the member when the SMA element tends to straighten under tension. SMA elements can be beam-shaped or rigid and may be capable of applying different forces (e.g., non-tensional) to the element. SMA elements may or may not include non-SMA materials and / or components. For example, an SMA element may include an SMA core and a coating of non-SMA materials. Unless the context requires otherwise, the term "SMA element" may refer to any configuration of SMA material that acts as a single actuating element, such that the single actuating element can be individually controlled to generate forces acting on the element. For example, an SMA element may include two or more portions of SMA material arranged mechanically in parallel and / or in series. In some arrangements, an SMA element may be part of a larger SMA element. Such a larger SMA element may include two or more components that can be individually controlled, thereby forming two or more SMA elements. SMA elements may include SMA wires, SMA foils, SMA films, or any other configuration of SMA material. SMA elements can be manufactured using any suitable method, such as by methods involving drawing, rolling, deposition, sintering, or powder melting. SMA elements can exhibit any shape memory effect, such as thermal shape memory or magnetic shape memory, and can be controlled in any suitable manner (e.g., by Joule heating, another heating technique, or by applying a magnetic field).

Claims

1. An actuator assembly, comprising: A first component and a second component, the first component and the second component being movable relative to each other; as well as At least one actuation unit, each actuation unit being configured to apply a corresponding actuating force to the second component upon actuation, the actuating force enabling the second component to move relative to the first component, wherein each actuation unit includes: - Main body; - A force adjustment element connected between the main body portion and the first component; - A connecting link, which connects the main body portion and the second component; and - An SMA element, connected between the body portion and the first component, wherein the SMA element is arranged to apply an input force to the body portion upon actuation, causing the body portion to rotate about an effective pivot point defined by the force adjusting element, such that the actuating force is applied to the second component via the coupling element. Wherein, i) the angle between the imaginary line between the effective pivot point P and the connection point between the SMA element and the main body and ii) the imaginary line between the effective pivot point P and the connection point between the connecting rod and the main body is greater than 135 degrees.

2. The actuator assembly according to claim 1, wherein, i) The angle between the imaginary line between the effective pivot point P and the connection point between the SMA element and the main body and ii) the imaginary line between the effective pivot point P and the connection point between the connecting rod and the main body is greater than 160 degrees, preferably greater than 170 degrees, and most preferably about 180 degrees.

3. The actuator assembly according to any one of the preceding claims, wherein, The force adjustment element includes a force adjustment flexure.

4. The actuator assembly according to any one of the preceding claims, wherein, The force adjustment element is arranged to be in a tensile state when the SMA element is actuated.

5. The actuator assembly according to any one of the preceding claims, wherein, The force adjustment element is arranged at a certain angle relative to the SMA element, preferably at an angle in the range of 13 degrees to 77 degrees, and optionally at an angle in the range of 13 degrees to 40 degrees or 77 degrees to 50 degrees.

6. The actuator assembly according to any one of the preceding claims, wherein, Each actuation unit is configured to amplify the actuation amount of the SMA element into a relatively larger amount of movement of the second component relative to the first component, optionally with an amplification factor greater than 1.5, preferably greater than 2, and more preferably greater than 3.

7. The actuator assembly according to any one of claims 1 to 5, wherein, Each actuation unit is configured to amplify the input force such that the actuating force is greater than the input force, optionally by a factor greater than 1.5, preferably greater than 2, and even more preferably greater than 3.

8. The actuator assembly according to any one of the preceding claims, wherein, The connecting rod includes a connecting flexure.

9. The actuator assembly of claim 8, wherein, The connecting rod is arranged to be in tension when the SMA element is actuated.

10. The actuator assembly according to claim 8 or 9, wherein, The angle between the connecting flexure and the SMA line is in the range of 70 degrees to 110 degrees.

11. The actuator assembly according to any one of the preceding claims, wherein, Each actuation unit extends essentially in the actuation plane.

12. The actuator assembly according to any one of the preceding claims, wherein, The main body and the force adjustment element are integrally formed from the same material, and optionally, the connecting rod is also formed from the same material.

13. The actuator assembly according to any one of the preceding claims, comprising a total of four actuation units, the actuation units being arranged to apply an actuating force such that none of the actuating forces are non-collinear.

14. The actuator assembly of claim 13, wherein, The four actuation units are arranged such that the first pair of actuation units apply actuating force in two opposite directions parallel to a first axis in the plane, and the second pair of actuation units apply actuating force in two opposite directions parallel to a second axis in the plane, wherein the first axis and the second axis are not parallel.

15. The actuator assembly of claim 14, wherein, The first pair of actuation units are arranged to apply torque to the second component relative to the first component in a first direction, and the second pair of actuation units are arranged to apply torque to the second component relative to the first component in a second direction, wherein the second direction is opposite to the first direction.

16. An actuator assembly comprising: A first component and a second component, the first component and the second component being movable relative to each other; as well as At least one actuation unit, each actuation unit being configured to apply a corresponding actuating force to the second component upon actuation, the actuating force enabling the second component to move relative to the first component, wherein each actuation unit includes: - Main body; - A force adjustment element connected between the main body portion and the first component; - A connecting link, which connects the main body portion and the second component; and - An SMA element, connected between the body portion and the first component, wherein the SMA element is arranged to apply an input force to the body portion upon actuation, causing the body portion to rotate about an effective pivot point defined by the force adjusting element, such that the actuating force is applied to the second component via the coupling element. Wherein, (i) the effective pivot point P, (ii) the connection point between the SMA element and the main body, and (iii) the connection point between the connecting rod and the main body are located on or near the imaginary line.

17. The actuator assembly according to any one of the preceding claims, comprising an image sensor and / or a lens assembly, wherein, The image sensor or the lens assembly is fixed relative to the second component and / or the lens assembly or the image sensor is fixed relative to the first component.

Images