Actuator assembly

Abstract

The present invention relates in general to an actuator assembly for facilitating or resisting movement of a body in relation to a support structure thereof. More particularly, the actuator assembly comprises one or more smart material actuators that when stimulated mechanically contract, thereby creating a force acting on the body to facilitate or resist movement of the body in relation to the support structure.

Description

[0001] ACTUATOR ASSEMBLY

[0002] TECHNICAL FIELD

[0003] The present invention relates in general to an actuator device for facilitating or resisting movement of an object connected or attached thereto. More particularly, the actuator device comprises one or more smart material actuators that when stimulated mechanically contract, thereby creating a force acting on the actuator to facilitate or resist movement of the object connected or attached thereto.

[0004] BACKGROUND

[0005] An actuator is in general a device responsible for enabling physical movement in a mechanical system. Hence, actuators are widely used whenever a physical movement of a component of a mechanical system is required. The physical movement is achieved by converting energy from an energy source into a mechanical force.

[0006] Various types include, soft actuators, hydraulic actuators, pneumatic actuators, electric actuators, thermal actuators, magnetic actuators, mechanical actuators.

[0007] While various types of actuators are commercially available there is an ongoing need for further developments, e.g. in terms of minimising the overall system weight, improving the response rate of the system, and / or adding new system functionality.

[0008] Hence, an improved actuator device for facilitating or resisting movement would be advantageous.

[0009] SUMMARY

[0010] According to a first aspect an actuator assembly is provided. The actuator assembly comprises a support structure, a body supported by the support structure, at least a first anchor zone attached to the support structure, at least a second anchor zone attached to the body, at least one first smart material actuator (SMA) connected between the first anchor zone and second anchor zone, and forming a first set of a first group of SMAs. Moreover, the assembly comprises a force translation mechanism connecting the first anchor zone to the second anchor zone and comprising the first group of SMAs. Each SMA is arranged to operate in an idle state, and an activated state triggered by a nonmechanical stimulus that causes the associated SMA to mechanically contract. Moreover, an activation unit is arranged to transmit said non-mechanical stimulus to each SMA individually in response to a defined activation sequence.

[0011] The first set of the first group of SMAs may comprise two or more SMAs arranged in sequence between the first anchor zone and the second anchor zone. The force translation mechanism may comprise one or more linkages, where each linkage may comprise at least one of a fibre, yarn, cable, wire, film, or strip. The one or more linkages may be rigid, non-flexible, or inelastic.

[0012] The force translation mechanism may comprise a first end anchored to the first anchor zone or second anchor zone and a second end attached to the at least one of the in-sequence SMAs.

[0013] The force translation mechanism may comprise at least one of: a first linkage connected between and attached to the first anchor zone and an SMA closest in sequence to the first anchor zone, a second linkage connected between and attached to two closest neighbouring SMAs, and a third linkage connected between and attached to the second anchor zone and a SMA closest in sequence to the second anchor zone.

[0014] The at least two SMAs connected in sequence may form part of a laterally detached or laterally attached SMA array and may comprise more than one group of SMAs.

[0015] A subgroup of SMAs of each group of SMAs may be arranged to act as a spring, to allow said subgroup to contract upon activation or extend upon deactivation of the respective subgroup SMAs.

[0016] The associated force translation mechanism of at least one of the groups of SMAs may further comprise a spring, damper or elastic member in sequence between the respective first anchor zone and the respective second anchor zone.

[0017] Each SMA may be selected from the group consisting of: photo-responsive actuators; dielectric or electro restrictive elastomer actuators (DEA); conductive polymer actuators (CP); electroactive polymer actuators (EAP); and magneto strictive actuators (MA).

[0018] The SMA array may be provided as a thin film array configured to conform around a curvature of the body.

[0019] The thin film may comprise a clear coating or plastic film applied over the array of SMAs, where the clear coating or plastic film may be arranged to translate actuation forces through its structure.

[0020] The first set of SMAs may be connected in sequence along a first direction between first anchor zone and the second anchor zone.

[0021] The first group of SMAs may further comprise a second set of SMAs connected in sequence between the first anchor zone and the second anchor zone along a second direction different from the first direction or in parallel with the first direction. The first group of SMAs may further comprise at least a third set of SMAs having two further smart material actuator(s) (SMAs) connected in sequence between the first anchor zone and second anchor zone. The third set of SMAs may be connected in sequence along a third direction between first anchor zone and the second anchor zone. The third direction may be different from the first or second direction or in parallel with the first or second direction.

[0022] The first, second or third set of SMAs of the first group of SMAs may be formed in an array.

[0023] The first set of SMAs of the first group of SMAs may be arranged in a first layer, and the second set of SMAs of the first group of SMAs may be arranged in a second layer. The second layer may at least partly overlap the first layer.

[0024] The activation unit may be releasably or fixedly attached to the support structure.

[0025] At least one of the SMAs may be a photo-responsive actuator. The activation unit may comprise a light source for transmitting light to activate said at least one SMA.

[0026] The activation unit may further comprise a light guide arranged to receive light from the said light source and direct said received light towards said at least one associated SMA.

[0027] The activation unit may comprise a Light Emitting Diode (LED) panel comprising at least one LED per SMA. The one or more LEDs of the LED panel may have a spatial configuration corresponding to that of the associated SMAs.

[0028] The activation unit may comprise a flexible Light Emitting Diode (LED) panel comprising at least one LED per SMA. The one or more LEDs of the flexible LED panel may have a spatial configuration corresponding to that of the associated SMAs.

[0029] The activation unit may comprise one or more LEDs attached to a flexible printed circuit board (PCB).

[0030] The activation unit may comprise one or more groups of LEDs, each group of LEDs may be arranged to activate one or more associated SMAs of the respective groups of SMAs.

[0031] The body may be arranged to move in relation to the support structure upon activation or deactivation of at least one of the SMA(s).

[0032] The actuator assembly may further comprise a connector unit attached to body and arranged to connect to a further component. The further component may be selected from the group comprising: an electronic device, an electromechanical device, mechanical device, a remote-controlled device, an aerospace component, a payload, a tool, a robotic member, and a control surface.

[0033] The body may have a spherical, round or oblong shape.

[0034] The support structure may comprise a number of ball bearings supporting the body, thereby allowing the body to move or roll in relation to the support structure.

[0035] The support structure may comprise a cone shaped portion, hollow pyramid shaped portion, cup shaped portion or socket portion, such as a ball bearing socket, for holding the body. The body may have a shape corresponding to that of the socket portion.

[0036] The actuator assembly may further comprise a second group of smart material actuators (SMA) connected between a further first anchor zone and a further second anchor zone.

[0037] The second group of smart material actuators may be at least partly oppositely arranged to the first group of first smart material actuators, thereby forming a first agonist-antagonist SMA pair.

[0038] The further second anchor zone of the second group of SMAs may be oppositely arranged to the second anchor zone of the first group of SMAs in relation to a first bisecting axis of the body.

[0039] The actuator assembly may further comprise: a third group of smart material actuators (SMA) connected between a further first anchor zone and a further second anchor zone, and a fourth group of smart material actuators (SMA) connected between a further first anchor zone and a further second anchor zone. The third group of smart material actuators may be at least partly oppositely arranged to the fourth group of first smart material actuators, thereby forming second agonist-antagonist SMA pair.

[0040] The further second anchor zone of the third group of SMAs may be oppositely arranged to the second anchor zone of the fourth group of SMAs in relation to a first bisecting axis of the body.

[0041] The actuator assembly may further comprise: a fifth group of smart material actuators (SMA) connected between a further first anchor zone and a further second anchor zone, and a sixth group of smart material actuators (SMA) connected between a further first anchor zone and a further second anchor zone. The fifth group of smart material actuators may be at least partly oppositely arranged to the sixth group of smart material actuators, thereby forming third agonist-antagonist SMA pair.

[0042] The further second anchor zone of the fifth group of SMAs may be oppositely arranged to the second anchor zone of the sixth group of SMAs in relation to a second bisecting axis (centre axis) of the body.

[0043] The second anchor zone of the first group of SMAs may be arranged 180 degrees offset from the second anchor zone of the second group of SMAs along the body perimeter.

[0044] The second anchor zone of the third group of SMAs may be arranged 180 degrees offset from the second anchor zone of the fourth group of SMAs along the body perimeter.

[0045] The second anchor zone of the first group of SMAs may be arranged 90 degrees offset from the second anchor zone of the third group of SMAs along the body perimeter. The second anchor zone of the second group of SMAs may be arranged 90 degrees offset from the second anchor zone of the fourth group of SMAs along the body perimeter.

[0046] The third agonist-antagonist SMA pair may be arranged essentially orthogonal to the first agonist-antagonist SMA pair and the second agonist-antagonist SMA pair.

[0047] The respective second anchor zone may be arranged on the exterior surface offset from a second bisecting axis (centre axis) of the body, thereby allowing for tangent pull.

[0048] BRIEF DESCRIPTION OF THE DRAWINGS

[0049] A number of examples will now be shown, by way of example, with reference to the following drawings, in which:

[0050] Figure 1 illustrates a side view of an actuator assembly comprising a first group of SMAs, in its idle state thereof, according to a first example;

[0051] Figure 2 illustrates a side view of the actuator assembly of Figure 1 in its activated state, i.e. where at least one or more SMAs of the first group of SMAs has been activated;

[0052] Figure 3 illustrates a side view of an actuator assembly according to another example, comprising a further group of smart material actuators, in its idle state thereof;

[0053] Figure 4 illustrates a side view of the actuator assembly of Figure 3 in its activated state, i.e. where at least one or more SMAs of the first group of SMAs has been activated; Figure 5 illustrates a side view of an actuator assembly according to yet another example, in its idle state, wherein respective parts of the activation unit 30 are arranged in close proximity to the respective group of SMAs;

[0054] Figure 6 illustrates a side view of the actuator assembly of Figure 5 in its activated state;

[0055] Figure 7 illustrates a side view of the actuator assembly (similar to that of Figure 5), in its idle state, according to another example, comprising at least one spring member arranged to return the body of the actuator assembly to its idle position upon deactivation of the one or more SMAs of the first group of SMAs;

[0056] Figure 8 illustrates a side view of the actuator assembly of Figure 7, in its activate state, wherein the spring member has reached an extended state due to at least one of more of the SMAs of the first group of SMAs being activated;

[0057] Figure 9 illustrates a side view of an actuator assembly according to another example, comprising three groups of smart material actuators, in its idle state thereof;

[0058] Figure 10 illustrates a side view of the actuator assembly of Figure 9, in its activated state, wherein at least some of the first group of SMAs have been activated;

[0059] Figure 11 illustrates a side view of an actuator assembly according to another example, comprising three groups of smart material actuators, in its idle state thereof, where each group of SMAs is connected to an in-line spring member;

[0060] Figure 12 illustrates a side view of the actuator assembly of Figure 11, in its activated state, wherein at least some of the first group of SMAs have been activated, and consequently the in-line spring member of the second group of SMAs being oppositely arranged the first group of SMAs has reached an extended state;

[0061] Figure 13 illustrates a top view of an actuator assembly, in its idle state, according to another example, comprising four groups of SMAs and forming two agonistantagonist SMA pairs.

[0062] Figure 14 illustrates a side view of an actuator assembly, in its idle state, according to yet another example, comprising six groups of SMAs (the two groups of SMAs at the back not shown ion Figure 14) and forming three agonist-antagonist SMA pairs;

[0063] Figure 15 illustrates a top view of the actuator assembly of Figure 14, in its idle state, showing the six groups of SMAs forming the three agonist-antagonist SMA pairs;

[0064] Figure 16 illustrates a side view of an actuator assembly according to yet a further example, having a cup shaped support structure for holding the body thereof;

[0065] Figure 17 illustrates a side view of an actuator assembly according to yet a further example, having a cone shaped support structure for holding the body thereof;

[0066] Figures 18a and 18b illustrates a top view of a group of SMAs connected in sequence in an idle state and activated state, respectively; and Figure 19 illustrates a top view of a photo-responsive smart actuator ID array according to an example.

[0067] DETAILED DESCRIPTION

[0068] A general idea of the present invention is to provide an actuator assembly comprising one or more discrete smart material actuator(s) (SMAs) that mechanically contract upon a non-mechanical stimulation to create a force that is translated to one or more anchor zones of the actuator. The actuator may comprise a support structure. The actuator may further comprise a body supported by the support structure.

[0069] The actuator assembly may be utilized to facilitate or resist movement of the body in relation to the support structure thereof. When the smart material actuators are stimulated / activated they mechanically contract, thereby creating a force acting on the body to facilitate or resist movement of the body in relation to the support structure.

[0070] The anchor zones may be arranged to the body. The force created by the activation of the smart material actuator(s) is translated to the body via the anchor zone(s) using a force translation mechanism (FTM). The force created by the activation of the SMA(s) allows the body to attain a desired orientation and / or location in relation to the support structure. The body may be configured to move in relation to the support structure, which in turn allows the body to attain various relative orientations in relation to the support structure. Depending on the type of application the created force may act to resist a movement of the body or facilitating a desired movement of the body.

[0071] As will be further elucidated below the movement may relate to a movement in three dimensions (3D), two dimensions (2D), and / or one dimension (ID).

[0072] The force created may in some examples be varied in magnitude by varying the magnitude of the non-mechanical stimulation.

[0073] In at least one example, the actuator further comprises a connector unit attachable, such as releasably or rigidly attached, to the body. The connector unit may further be arranged to connect to a further component. Since the connector unit is attached to the body, the connector unit will inherently move in relation to the support structure based on the activation and / or deactivation of the SMAs.

[0074] In at least one example, the actuator assembly is arranged to act as a rotational actuator.

[0075] In at least example, the actuator assembly acts as a gimbal and / or stabiliser unit for the further component. The further component may pertain to an electronic device, an electromechanical device, mechanical device, a remote-controlled device, an aerospace component, a payload, a tool, a robotic member, a control surface.

[0076] In at least one example, the further component pertains to a camera. This allows the actuator assembly to act as a gimbal and / or stabiliser for the camera.

[0077] In some examples, the actuator assembly may be used as a workout device, where the user acts to work against the force created upon activation of the associated smart material actuators.

[0078] In other examples, the actuator assembly may be used as medical rehabilitation device, allowing patients with impaired mobility to achieve a higher degree of mobility, e.g. by connecting a workout, or training equipment to the connector unit of the actuator assembly disclosed herein.

[0079] With reference to Figure 1 a first example of an actuator assembly 100 for is shown. The actuator assembly may be used to act as a gimbal and / or stabiliser unit for a further component. In some examples, the further component may pertain to a camera or the like, which may allow the actuator assembly to act as a gimbal and / or stabiliser therefor.

[0080] The actuator assembly 100 may comprise support structure 101. The actuator assembly may further comprise a body 102 supported by the support structure 101. Moreover, the actuator assembly may comprise at least a first anchor zone 11 (e.g., first anchor zone Ila) attached to the support structure 101 and / or at least a second anchor zone 12 (e.g., second anchor zone 12a) attached to the body 102. The actuator assembly 100 may further comprise at least one first smart material actuator (SMA) 21 connected between the first anchor zone 11 and second anchor zone 12, forming a first set of a first group of SMAs. Further, the actuator assembly 100 may comprise a force translation mechanism 20 connecting the first anchor zone 11 to the second anchor zone 12 and may comprise the first group of SMAs.

[0081] Each SMA 21 may be arranged to operate in an idle state (or non-activated state) and an activated state. The activated state may be triggered by a stimulus (e.g., non-mechanical stimulus) that causes the associated SMA to mechanically contract.

[0082] Further, the actuator assembly 100 may comprise an activation unit 30 may be arranged to transmit said stimulus to each SMA individually in response to a defined activation sequence.

[0083] Rather than utilizing a long SMA, e.g. an SMA fibre or yarn extending completely between two or more anchor zones, utilizing discrete SMAs connected in sequence between two or more anchor zones can attain a desired overall total force may be attained while at the same time utilizing the higher response rate of the discrete SMAs.

[0084] Further, arranging two or more SMAs in sequence allows for activation of a number of the SMAs in the sequence in a local region between the two anchor zones. When combined with activation of additional sets and / or groups of neighbouring in sequence SMAs in a second local region, various types of forces (e.g., torsional) can be created. These forces allow for the actuator assembly 10 to be more versatile and allows for the assembly to resist or facilitate various movements, in use.

[0085] The first set of SMAs of each group may be connected in sequence along a first direction, such as a longitudinal direction, between first anchor zone and the second anchor zone. The first set of the first group of SMAs 21 can comprises two or more SMAs 21 arranged in sequence between the first anchor zone 11 and the second anchor zone 12.

[0086] A technical effect of the force translation mechanism is to translate a force, such a pulling force, that is created by each activated SMA, between the respective activated SMA and the anchor zones 11 and 12. As the at least two SMAs are connected in sequence between the first anchor zone 11 and second anchor zone 12, upon activation of the associated SMAs, the force translation mechanism will act to pull or force the first anchor zone towards the second anchor zone and vice versa. Accordingly, e.g., in the activated state, in response to the activation the created force acts to reduce the longitudinal distance between the first anchor zone 11 and the second anchor zone 12, compared to the idle state.

[0087] In situations where there is no external or opposing force acting in an opposite longitudinal direction to that of the created force and being equal or larger than the created force, the longitudinal distance between the two anchor zones will be reduced.

[0088] When the external or opposing force is equal to the created force, the longitudinal distance will remain constant.

[0089] When the external or opposing force is larger than the created force, the longitudinal distance will be increased.

[0090] In some examples, the opposing force may be applied by the further component.

[0091] In some examples, the associated SMAs are controlled to create a force depending on the magnitude of the external or opposing force, or on a sensed movement of the further component associated with the external or opposing force. In some examples, the body 102 is arranged to move in relation to the support structure 101 upon activation or deactivation of at least one of the SMA(s). The body 102 may comprise a spherical, round, or oblong shape.

[0092] The support structure 101 may be configured to support the body 102. The support provided by the support structure 101 to the body 102 allows for the body 102 to move or roll in relation to the support structure 101. The support member 101 may comprise a cone shaped portion, hollow pyramid shaped portion, cup shaped portion and / or socket portion (e.g., a ball-bearing socket). The body 102 may comprise a shape that is complementary or corresponding to that of the support structure 101 (e.g., a shape that corresponds to a socket portion of the support structure 101).

[0093] In some examples, the support structure 101 comprises one or more ball bearings for supporting the body 102.

[0094] The actuator assembly 100 may further comprise a connector unit 40 attached to body 102 and arranged to connect to the further component.

[0095] The further component may be selected from (but is not limited to) the group comprising: an electronic device, an electromechanical device, mechanical device, a remote-controlled device, an aerospace component, a payload, a tool, a robotic member, and a control surface.

[0096] As will be further elucidated below, in some examples the magnitude of the force created by activation of the associated SMAs is tailored to continuously match that of the body 102 and / or the further component, such that the distance between the first anchor zone 11 and the second anchor zone 12 is maintained constant or substantially constant. This allows for providing force feedback, allowing for a cancellation of a force and / or halt of a motion of the body 102 secured to a first anchor zone and / or second anchor zone, in use. This also allows the actuator assembly to act as a stabiliser and / or gimbal. Hence, the associated SMAs may be controlled to create a force to match that of an opposing force to maintain the distance between the first and second anchor zones constant or substantially constant.

[0097] The opposing force may be associated with a force from the body 22 and / or the further component.

[0098] A controller (not shown), may be operatively coupled to the activation unit 30 and / or may be configured to execute the activation sequence(s) in order to control the activation unit 30.

[0099] The controller may be a microcontroller operatively coupled to a memory and arranged to execute a number of computer executable instructions, optionally stored on a non-transitory computer readable medium. The processor may be operatively coupled to a control circuit for controlling the operation of the activation unit 30. In some examples, the control circuit forms part of the activation unit 30.

[0100] Each SMA may be selected from the group consisting of: Photo-responsive actuators, Dielectric or electro restrictive elastomer actuators (DEA), Conductive polymer actuators (CP), Electroactive polymer actuators (EAP); and Magneto strictive actuators (MA). The control circuit may be arranged to control stimulation intensity of the associated activation unit 30. Depending on the type of activation unit and associated SMA, the stimulation intensity may relate to light for photo responsive SMAs, voltage level for Dielectric or electro restrictive elastomer actuators (DEA), Conductive polymer actuators (CP), or Electroactive polymer actuators (EAP) or magnetic flux for Magneto strictive actuators (MA).

[0101] In some examples, the activation sequence may be derived by the controller based on sensor information accessed by the controller. For example, the sensor information may comprise strain sensor information from one or more strain sensors sensing movement and / or rotation of the body 102 and / or the further component connected thereto. Alternatively, or additionally the sensor information may comprise accelerometer or gyroscopic information from one or more accelerometers or gyroscopes attached to the body 102 and / or the further component. Optionally, the sensor information may comprise Electroencephalogram (EEG) or Electromyography (EMG) information.

[0102] Based on the sensor information, the controller may be configured to control (e.g. adjust or regulate), either intensity of stimulus, percentage of SMA material stimulated, or a ratio of stimulated SMA material and varied directions to create a desired created force or longitudinal distance displacement between the first anchor zone and second anchor zone.

[0103] In some examples, the first anchor zone may be made integral with the support structure 101, and / or the second anchor zone may be integral with the body 102. Alternatively, the body 102 may comprise a material to which the second anchor zone is fixedly attached.

[0104] The material may be fixedly or releasably attached to the body 102 and / or the one or more of the SMAs.

[0105] Figure 2 illustrates the actuator assembly 100 (of Figure 1) in its activated state, i.e. where at least one or more SMAs of the first group of SMAs has been activated. In this configuration, due to the activation of the at least one or more SMAs of the first group of SMAs, the position and / or or orientation of the body 102 is configured to change, in respect to the support structure 101. Since the connector unit 40 is attached to the body 102, it may also experience the same or similar changed in its relative position.

[0106] Figure 3 shows the actuator assembly 100 according to another example, where the assembly 100 comprises a further (second) group of SMAs, in its idle state thereof. Figure 4 illustrates, the actuator assembly 100 (of Figure 3) in its activated state, i.e. where at least one or more SMAs of the first group of SMAs has been activated. In this configuration, due to the activation of the at least one or more SMAs of the first group of SMAs, the position and / or or orientation of the body 102 is configured to change, in respect to the support structure 101. Since the connector unit 40 is attached to the body 102, it may also experience the same or similar changed in its relative position. Similarly, since the second group of SMAs is attached to the body 102, its configuration and / or position is also altered as a result.

[0107] Each SMA in the sequence is directly attached to one or more SMAs. Alternatively, or additionally each SMA in the sequence could be directly attached to one or more anchor zone(s), as shown with reference to Figures 3 and 4. Each SMA may be directly attached to one of the further SMA(s) or anchor zone(s) at either a first longitudinal end 21a', 21b' or second longitudinal end 21a", 21b" thereof. In some examples, each SMA is directly attached to next SMA in sequence and / or to an associated anchor zone 11 and 12 using an adhesive or seam.

[0108] However, in alternative examples, at least one of the SMAs may be attached to a neighbouring SMA or anchor zone via a linkage, schematically shown as solid lines linking the SMAs to the respective anchor zones in Figures 18a and 18b, that in turn is directly attached to said SMA and the neighbouring SMA or anchor zone. The linkage member(s) form part of the force translation mechanism 20.

[0109] The number of linkages used may e.g. depend on the physical distance between the two connected anchor zones in the idle state, and the number of and associated size of the SMAs connected in sequence therebetween. The number of SMAs in turn may be selected based on the desired magnitude of the force to be created between the anchor zones when each SMA is activated. For example, six linkages 20a, 20b, 20c are shown with reference to Figures 18a and 18b, and multiple linkages are shown with reference to Figures 1 to 15.

[0110] The linkages of the force translation mechanism may extend along or parallel to a longitudinal direction or axis (L) between the first and second anchor zone, along which longitudinal direction the respective SMAs are connected in sequence. To this end, the linkages of the force translation mechanism may be referred to as longitudinal linkages. For example, considering an assembly having two connected anchor zones displaced 100mm apart in an idle state along a longitudinal direction or axis, and with four SMAs, each 20mm in size, a resulting space of 20mm, i.e. 100mm-4*20mm=20mm out of the 100mm may be provided with one or more longitudinal linkages.

[0111] The force translation mechanism is formed by the associated SMAs, and their associated attachments to other SMAs or anchor zones, and any optional linkages.

[0112] An underlying idea of the force translation mechanism is to provide minimal slack for each group of in sequence SMAs connected between the associated anchor zones. In this way, a majority of the force created when activating the SMA, e.g. up to 95%, may be translated from the associated SMAs to the anchor zones. In some examples, the force translation mechanism has a force translation efficiency of about 85% to about 95%. While a 100% force translation efficiency would be ideal, in practice there will always be efficiency losses caused by undesired deformation of the force translation mechanism, or adjacent materials connected thereto, resulting in reducing the overall force translation efficiency from the ideal value.

[0113] In some examples, the one or more linkages may comprise comprises at least one of a fibre, yarn, cable, wire, film, or strip, with an elastic modulus 6 = stress / strain, e.g. a Youngs modulus, being higher than a predetermined threshold.

[0114] The predetermined threshold may be set higher than the force created by the associated SMAs, thereby limiting the tendency of the linkage to deform along the longitudinal axis along which the SMAs are connected in sequence between first anchor zone 11 and second anchor zones 12, when the SMAs are activated.

[0115] In an example, one or more linkages are rigid, non-flexible, or inelastic. This allows the linkages to translate the force created along or parallel to said longitudinal direction when the associated SMAs are activated.

[0116] The linkages may be strong enough to withstand failure at a maximum compounded force generation. On the other hand, the linkages may have a degree of flexibility along any non-longitudinal direction. For example, a cable like linkage may be preferred over a push rod type linkage for this reason.

[0117] The linkages may have a first end and second end opposite the first end. The respective ends of the linkage may be arranged to be anchored to either an anchor zone 11, 12 or to a longitudinal end an SMA of the sequence of SMAs forming a group of the SMAs. In some examples, the linkages are anchored using an adhesive or mechanical attachment, such as a seam. In some examples, a shown with reference to Figures 18a to 18b, the force translation mechanism 20 comprises at least one of: a first linkage 20a connected between and attached to the first anchor zone and an SMA closest in sequence to the first anchor zone 11, a second linkage 20b connected between and attached to two closest neighbouring SMAs, and a third linkage 20c connected between and attached to the second anchor zone and a SMA closest in sequence to the second anchor zone.

[0118] In some examples, the force translation mechanism may comprise no linkages, whereby each SMA 21a to 21g (in each set of SMAs) of the sequence is directly attached to either another SMA and anchor zone or two neighbouring SMAs.

[0119] In an alternative example, the force translation mechanism may further be connected to a damper or spring member arranged to dampen out the reduction in longitudinal distance between the associated anchor zones 11, 12 upon activation of the associated SMAs 21a-21g. The damper may comprise a tension spring (not shown) that smoothens out any abrupt relative movements between the first 11 and second 12 anchor zones, as show with reference to Figures 11 to 12. In some examples the spring may be arranged separate from the force translation mechanism. Such a configuration is shown with reference to Figures 7 and 8. A spring member allows for the associated further component secured to the body via the respective anchor zones to move smoothly upon activation of the associated SMAs. For example, a damper may be attached between the first anchor zone and the first SMA in sequence, as shown in Figures 11 and 12. Hence, each group of SMAs may be connected to damper arranged to dampen out the force created upon activation of the associated SMAs, thereby smoothing out any abrupt reduction of the longitudinal distance.

[0120] In some examples, the force translation mechanism (20) of at least one group of groups of SMAs can further comprise a spring, damper or elastic member. These may be positioned in sequence between the respective first anchor zone (11) and the respective second anchor zone (12), e.g., as shown in Figures 7 and 8.

[0121] In some examples, there may be provided a subgroup of SMAs of each group of SMAs, which may be arranged to act as a spring. This may allow the subgroup of SMAs to contract upon activation or extend upon deactivation of the respective group of SMAs. A possible example is shown in Figures 9 and 10. In such examples, when in the idle state, a subgroup of SMAs in each group of SMAs are pre-activated. This is clearly demonstrated by Figure 9, where the subgroup of SMAs of each group of SMAs are observed to be shorter than the remainder of the respective group of SMAs. The subgroup of SMAs may be positioned at the bottom of the respective group of SMAs. Moreover, in such examples, when in the activated state, other parts or the entirety of the first group of SMAs (i.e., SMA(s) other than those belonging to the subgroup of SMAs) are activated and the pre-activated subgroup of the SMAs of the opposing group of SMAs are deactivated. This is clearly demonstrated by Figure 10, where all or substantially all of the SMAs of the group of SMAs on the left (i.e., the first group) are activated (i.e., they are shorter) and the pre-activated subgroup of SMAs of the opposing groups of SMAs are deactivated (i.e., they are longer).

[0122] With reference to Figures 1 and 15, and 19 the first group of in-sequence SMAs 21a-21g may be formed as a strip or ID array of discrete SMAs. In some examples, the strip or array may comprise a film 51, e.g. a thin film, encapsulating the SMAs. In this way, the film forms one or more linkages of the force translation mechanism. The film may be selected from a material configured to allow for conforming with the curvature of the body of the actuator assembly.

[0123] For example, the thin film may comprise a clear coating or plastic film applied over the array of SMAs, wherein the clear coating or plastic film is arranged to translate actuation forces through its structure.

[0124] Figure 18a shows an example where a first group of SMAs 21a-21e connected in sequence are present in their idle state, i.e. non-activated state. In the idle state the longitudinal distance between the first anchor zone 11 and the second anchor zone 12 is represented by Di. Upon activation by the activation unit (not shown) the respective SMA 21a-21e mechanically contracts and this situation is shown in Figure 18b. Upon no external force, or an external force being less than that created by the activation of the associated SMAs, as the SMAs 21a-21e are physically linked to the anchor zones, by the force translation mechanism 20 and in this example via a number of linkages 20a-20c of the force translation mechanism, the created forced resulting from the mechanical contraction, is translated to the respective anchor zones. This is turn acts to pull the first anchor zone 11 and the second anchor zone 12 towards each other, whereby the longitudinal distance between the anchor zones in the activated state is reduced in comparison to that of the idle state. The resulting reduced longitudinal distance between the first anchor zone 11 and the second anchor zone 12 in the activated state is represented by DA in Figure 18b. It may be observed from Figures 18a and 18b that the longitudinal distance DA clearly is smaller than the longitudinal distance Di. However, upon the presence of an external force, such as an external force acting in an opposite direction to that of the created force, and having a magnitude equal to that of the created force, the longitudinal distance may be kept constant or substantially constant, as discussed above. The distance Di and DA are also shown with reference to Figures 1 to 12, and 14. Upon activation the SMAs mechanically contract, which results in a shortening the length of the force translation mechanism and the distance between the first and second anchor point by AD= DI-DA (compare with Figures 18a and 18b). Hence, while the individual lengths of the linkages remain the same upon activation, the reduction in length of the force translation mechanism is fully due to the mechanical contraction of the SMAs. The mechanical contraction results in a force pulling the first anchor zone 11 towards the second anchor zone 12 or vice versa.

[0125] To create an increased force between the first anchor zone 11 and second anchor zone 12 of each group of SMAs, a second set of in-sequence SMAs 21a', 21b', optionally formed as a second strip or second ID array, may be connected to the first anchor zone 11 and second anchor zone 12 and spaced laterally to the first set of SMAs of the first group of SMAs.

[0126] In some examples, the second set of in-sequence SMAs, may be arranged in parallel to the first group of SMAs.

[0127] The second set of SMAs may be also connected in sequence between the first anchor zone and the second anchor zone along a second direction different from the first direction or in parallel with the first direction.

[0128] The second set of in-sequence SMAs may be laterally detached from the first set of SMAs. This implies that no part of the second set is attached to the first set other than indirectly via the first and second anchor zones. Laterally detaching the first set from the second set of each group of SMAs allows for the created force from each group of SMAs to substantially only act along the longitudinal direction along which the in-sequence SMAs are connected.

[0129] The at least two laterally detached sets of in-sequence SMAs may be said to form a laterally detached 2D array of in sequence SMAs.

[0130] In an alternative example, two or more sets of SMAs of a group of SMAs may be laterally attached to one another via lateral linkages to form a 2D array. The lateral linkages may allow the sets of SMAs to maintain a desired lateral spacing when activated in parallel. In this way, the lateral attachments provide for lateral stabilisation of the two groups when activated. This is particularly advantageous when the two or more set of SMAs are designed to be activated in parallel, as this allows for minimized skewing or splaying of neighbouring SMAs as compared to when each group is activated while neighbouring groups of SMAs are operating in their idle states. The at least two laterally attached groups of in-sequence SMAs may be said to form a laterally attached 2D array of in sequence SMAs.

[0131] Hence, depending on the application, the first set of SMAs 21a-21g and the one or more second set of SMAs 21a'-21g' may be arranged in an array with other sets of SMAs that are either laterally detached or laterally attached to another set of SMAs of the array.

[0132] In some examples, each set of SMA of each group are arranged in parallel with the other SMA sets of the same group, whereby the respective SMAs of each group is connected in-sequence along the same direction, such as a longitudinal direction (L) extending between the first anchor zone 11 and the second anchor zone 12.

[0133] In some examples, the second set of SMAs 21a'-21g' of each group, that are connected in sequence between the first anchor zone 11 and second anchor zone 12 may be connected in sequence along a second direction (!_') between first anchor zone and the second anchor zone. The second direction of the second group of SMAs may be different to the first direction of the first set of SMAs.

[0134] In some examples, with reference to Figure 11, the second set of SMAs 21a'- 21g' are formed in a laterally detached or laterally attached array comprising at least one further set of in-sequence connected SMAs 21a"-21g" arranged in parallel to the second direction (!_'), and the first set of SMAs 21a-21g is arranged along a first direction (L), wherein the first direction (L) differs from the second direction (!_').

[0135] In some examples, a combination of laterally detached and laterally attached SMA arrays may be used.

[0136] In at least one example, the first group of SMAs further comprises at least a third set of SMAs having two further smart material actuator(s) (SMAs) connected in sequence between the first anchor zone and second anchor zone, wherein the third set of SMAs are connected in sequence along a third direction between first anchor zone and the second anchor zone, wherein the third direction is different from the first or second direction or in parallel with the first or second direction.

[0137] The first, second or third set of SMAs of the first group of SMAs are formed in an array.

[0138] In at least one example, the first set of SMAs of the first group of SMAs are arranged in a first layer, and the second set of SMAs of the first group of SMAs are arranged in a second layer, wherein the second layer at least partly overlaps the first layer. The various layers could e.g. be enclosed in a housing. The SMAs of each layer may be arranged in sequence along a set direction, which may differ from the direction along which in sequence SMAs of a neighbouring layer are arranged. Arranging the SMAs in layers may increase the density of SMAs, thereby enabling creation of a larger force when more SMAs are activated together. Further, when arranging the SMAs in layers, where each layer comprises SMAs connected in sequence along a direction that differs from the direction along which the in sequence SMAs of a neighbouring layer are arranged, it is possible to create various types of forces in various directions. Hence, upon activation of the SMAs of each layer with SMAs connected in sequence along different directions, the body of the actuator assembly will be pulled in the different directions simultaneously, thereby creating a both a force having a longitudinal component and a force having a lateral component, resulting in an overall torsional force.

[0139] In some examples, the respective anchor zone 11, 12 may be pivotably arranged to the respective support structure 101 or body 102.

[0140] The anchor zones may be secured to the body 102 e.g. using elastic garters, belt-ratchet type mechanisms (similar to those used of bag strap adjustment), Velcro in conjunction with elastic strips, buttons, and / or zips.

[0141] In an example, at least one SMA is a photo-responsive actuator. The activation unit 30 may comprise a light source for transmitting light to activate the at least one SMA.

[0142] The photo-responsive actuator may be a photoactive polymer monomer, such as 2,4-dihydroxy-4-nitroazobenzene, or 2,4-dihydroxy-4-azo-(4-nitroazobenzeno)benzene. The present inventors have through various experiments realised that these photoactive polymer monomers provide for a suitable specific strength sufficient for scaling to a macroscale actuation, allowing for fast response rates, and / or enabling for any electronics to be safely isolated.

[0143] However, in alternative examples, the SMA may also be selected from the group consisting of Dielectric or electro restrictive elastomer actuators (DEA), Conductive polymer actuators (CP), Electroactive polymer actuators (EAP), and Magneto strictive actuators (MA).

[0144] In some examples, the activation unit 30 may be releasably or fixedly attached to the support structure. Arranging the activation unit 30 in a fixed relation to the respective SMAs may be advantageous for some types of SMAs, e.g. photo responsive SMAs, where the overall efficiency is improved when light is directed towards each SMA from at a certain angle and intensity. For example, Figure 5 to 12, and 14 show parts of the activation unit 30 arranged adjacent or in the immediate vicinity of the respective group of SMAs. In at least one example, these activation unit parts may be arranged to direct light towards each group of SMAs.

[0145] For example, the activator unit may be provided in a location that minimizes bulk and disruption to movement.

[0146] In some examples, the activation unit 30 is arranged distinct from the support structure. For example, the activation unit or at least parts thereof may be remotely arranged.

[0147] For the examples, wherein the smart material actuators are of a photo- responsive type, the activation unit comprises a light source for transmitting light to activate each SMA.

[0148] In some examples, the activation unit comprises a number of light sources provided in a configuration, e.g. an array corresponding to that of the groups of SMAs. For example, the activation unit 30 of each of Figures 1 to 12, and 14 may comprise a number of LED strips, conforming with the shape of each group of SMAs. It should be appreciated that any number of LED strips is possible. In some examples, the number of LED strips is less than the number of SMA groups, whereby each LED strip may be used to activate more than one SMA group.

[0149] The activation unit 30 may further comprise a light guide (as indicated by the arrows extending from the activation unit 30) arranged to receive light from the said light source and direct said received light towards one or more SMAs.

[0150] Using light guides which are inherently flexible, it is possible to arrange the respective light guide at a predetermined distance, and at a predetermined orientation in relation to one or more SMAs when in the idle state.

[0151] In some examples, the light guides are physically detached from the respective group of in sequence SMAs.

[0152] The activation unit 30 may comprise a Light Emitting Diode (LED) panel, such as a flexible LED panel.

[0153] In some configurations the LED panel or flexible LED panel may comprise at least one LED per SMA, wherein the one or more LEDs of the LED panel has a spatial configuration corresponding to that of the associated SMAs. However, in alternative examples the spatial configuration of the LEDs of the LED panel may differ from that of the SMAs. Hence, a one-to-one spatial configuration match between each SMA and a respective LED of the LED panel may not be required. Instead, one or more LEDs of the LED panel roughly covering any associated SMA may be activated for activation of the respective SMA, or vice versa.

[0154] Alternatively, the activation unit may comprise one or more LEDs attached to a flexible printed circuit board (PCB), that is arranged in close proximity to the associated photo responsive SMAs.

[0155] The one or more LEDs or the LED panel may be attached to the locations of associated SMAs.

[0156] In some examples, the LEDs of the LED panel may be arranged to transmit blue, ultraviolet and / or green light. In some examples, the blue, ultraviolet and / or green LEDs are alternating over the LED panel.

[0157] For the photo-responsive actuators identified above, some wavelengths are particularly effective at causing chiral change, i.e. compound shape change. For example, depending on the type of photo-responsive actuator selected shorter wavelengths such as ultraviolet (UV) wavelengths (<400nm) or blue wavelengths in the end of the visual spectrum may cause a mechanical contraction, while longer wavelengths, such as green wavelengths (~550nm) may cause a mechanical expansion of the photo-responsive actuator. Wavelengths in between the UV and green, such as a range of blue wavelengths (400-550nm) may cause mechanical contraction or expansion depending on the selected type of SMA. Emitting light in these wavelengths may allow for fine tuning the mechanical contraction and / or expansion in terms of percentage contraction. The selection of wavelengths also affects the response rate as some types of photo responsive SMAs are more responsive to particular wavelengths. Further, some wavelengths may be advantageous for causing a long-term shape change of the associated SMA while other wavelengths allow for only a short-term shape change of the associated SMA after the activation unit emitting electromagnetic radiation using said wavelengths has been deactivated.

[0158] In at least one example, the activation unit 30 may be a luminescent film or panel.

[0159] Alternatively, an electroluminescent paint forming part of the activator unit may be used to form a thin film light source, wherein light is emitted when the paint is electrically stimulated by electrodes.

[0160] Alternatively or additionally, bioluminescence where light is emitted by living organisms or chemiluminescence where light is produced as a result of chemical change / reaction could also be used as a light source. The electrical components of the actuator assembly 100, e.g. the controller and the activation unit may be powered by a power pack. In some examples, the power pack is configured to be attached to the actuator assembly 100. The power pack may comprise one or more batteries, e.g. rechargeable batteries. Any conventional battery could be used, e.g. lithium-ion batteries, etc.

[0161] In some examples, the actuator assembly 100 further comprises a Human Machine Interface (HMI) connected to the controller that allows the user or person to interface with the controller. The HMI may comprise a power ON / OFF function. Alternatively, or additionally the HMI interface may comprise a wireless communications interface, e.g. Bluetooth, WIFI or NFC allowing control of the operation of the controller. For example, parameters such as range of motion and resistance may be adjusted using a smartphone app or PC operatively coupled to the wireless communications interface.

[0162] The HMI may comprise physical buttons, or touch buttons to control various operation modes or functionalities of the controller. The HMI could further comprise a display unit such as a touch screen allowing for displaying of information related to power state, battery life, or optionally biometric data (e.g. heartrate, step count) collected from various biometric sensors. LED indicators may also be integrated into the HMI to power state (ON / OFF) etc.

[0163] The activation sequence may be programmed to follow certain exercise movements for rehabilitation purposes. Alternatively, the activation sequence may be programmed by a_clinician or patient to fine-tune biomechanical parameters to tailor to each patient need for active mobility purposes. The activation sequence may also be programmed to assist the persons own movements to assist in lifting exercises etc. For example, the controller may be programmed to allow for adjustment of the amount of assistance required, according to a scale such as between 0% and 100%, such as via a smartphone application connected to the wireless communications interface.

[0164] While the examples above are described with reference to an actuator assembly that may be used for a gimbal and / or stabiliser unit for a further component, it should be appreciated that the actuator assembly alternatively could be adapted and designed for other similar and / or suitable applications.

[0165] In at least one example, such as shown with reference to Figures 3 and 8, the actuator assembly further comprises a second group of smart material actuators (SMA) 22 / 23 connected between a further first anchor zone llb / llc and a further second anchor zone 12b / 12c. The second group of smart material actuators 22 may be at least partly oppositely arranged the first group of first smart material actuators 21, thereby forming a first agonist-antagonist SMA pair 21, 22.

[0166] The further second anchor zone 12b of the second group of SMAs 22 may be oppositely arranged the second anchor zone 12a of the first group of SMAs 21 in relation to a first bisecting axis of the body.

[0167] In at least one example, the actuator assembly further comprises a third group of smart material actuators (SMA) 23 connected between a further first anchor zone lies and a further second anchor zone 12c. The actuator assembly may further comprise a fourth group of smart material actuators (SMA) 24 connected between a further first anchor zone lid and a further second anchor zone 12d, wherein the third group of smart material actuators 23 is at least partly oppositely arranged the fourth group of first smart material actuators 24, thereby forming second agonist-antagonist SMA pair 23, 24. This configuration is perhaps best shown with reference to Figure 13.

[0168] The further second anchor zone 12c of the third group of SMAs 23 may be oppositely arranged the second anchor zone 12d of the fourth group of SMAs 24 in relation to a first bisecting axis of the body.

[0169] In a further example, the actuator assembly comprises a fifth group of smart material actuators (SMA) 25 connected between a further first anchor zone (lie) and a further second anchor zone 12e. The actuator assembly may further comprise a sixth group of smart material actuators (SMA) 26 connected between a further first anchor zone Ilf and a further second anchor zone 12f, wherein the fifth group of smart material actuators 25 is at least partly oppositely arranged the sixth group of smart material actuators 26, thereby forming third agonist-antagonist SMA pair 25, 26. This configuration is best shown with reference to Figured 14 and 15.

[0170] The further second anchor zone 12e of the fifth group of SMAs 25 may be is oppositely arranged the second anchor zone 12f of the sixth group of SMAs 26 in relation to a second bisecting axis (centre axis) of the body.

[0171] In at least one example, the second anchor zone 12a of the first group of SMAs is arranged 180 degrees offset the second anchor zone 12b of the second group of SMAs along the body perimeter. Such a configuration is shown in Figures 9 to 15.

[0172] The second anchor zone 12c of the third group of SMAs is arranged 180 degrees offset the second anchor zone 12d of the fourth group of SMAs along the body perimeter. Such a configuration is perhaps best shown with reference to Figures 13 and 15. According to one example, the second anchor zone 12a of the first group of SMAs is arranged 90 degrees offset the second anchor zone 12c of the third group of SMAs along the body perimeter, and the second anchor zone 12b of the second group of SMAs is arranged 90 degrees offset the second anchor zone 12d of the fourth group of SMAs along the body perimeter. Such a configuration is perhaps best shown in Figures 13 and 15.

[0173] In some examples, the third agonist-antagonist SMA pair 25,26 is arranged essentially orthogonal to the first agonist-antagonist SMA pair 21,22 and the second agonist-antagonist SMA pair 23,24. Such a configuration is perhaps best shown with reference to Figures 14 and 15.

[0174] The respective second anchor zone may be arranged on the exterior surface offset a second bisecting axis (centre axis) of the body, thereby allowing for tangent pull. Such a configuration is shown in each of the Figures 1 to 15.

Claims

CLAIMS:

1. An actuator assembly, comprising a support structure, a body supported by the support structure, at least a first anchor zone attached to the support structure, at least a second anchor zone attached to the body, at least one first smart material actuator (SMA) connected between the first anchor zone and second anchor zone, and forming a first set of a first group of SMAs, a force translation mechanism connecting the first anchor zone to the second anchor zone and comprising the first group of SMAs, wherein each SMA is arranged to operate in an idle state, and an activated state triggered by a non-mechanical stimulus that causes the associated SMA to mechanically contract, and an activation unit arranged to transmit said non-mechanical stimulus to each SMA individually in response to a defined activation sequence.

2. The actuator assembly, according to claim 1, wherein the first set of the first group of SMAs comprises two or more SMAs arranged in sequence between the first anchor zone and the second anchor zone.

3. The actuator assembly according to any one of the preceding claims, wherein the force translation mechanism comprises one or more linkages, wherein each linkage comprises at least one of a fibre, yarn, cable, wire, film, or strip.

4. The actuator assembly according to claim 3, wherein the one or more linkages is rigid, non-flexible, or inelastic.

5. The actuator assembly according to any one of the preceding claims, wherein the force translation mechanism comprises a first end anchored to the first anchor zone or second anchor zone and a second end attached to the at least one of the in-sequence SMAs.

6. The actuator assembly according to any one of claims 3 to 5, wherein the force translation mechanism comprises at least one of: a first linkage connected between and attached to the first anchor zone and an SMA closest in sequence to the first anchor zone, a second linkage connected between and attached to two closest neighbouring SMAs, and a third linkage connected between and attached to the second anchor zone and a SMA closest in sequence to the second anchor zone.

7. The actuator assembly according to any one of the preceding claims, wherein the at least two SMAs connected in sequence form part of a laterally detached or laterally attached SMA array comprising more than one group of SMAs.

8. The actuator assembly according to any of the preceding claims, wherein a subgroup of SMAs of each group of SMAs, are arranged to act as a spring, to allow said subgroup contract upon activation or extend upon deactivation of the respective subgroup SMAs.

9. The actuator assembly according to any of the preceding claims, wherein the associated force translation mechanism of at least one of the groups of SMAs further comprises a spring, damper or elastic member in sequence between the respective first anchor zone and the respective second anchor zone.

10. The actuator assembly according to any of the preceding claims, wherein each SMA is selected from the group consisting of:Photo-responsive actuators;Dielectric or electro restrictive elastomer actuators (DEA);Conductive polymer actuators (CP);Electroactive polymer actuators (EAP); and Magneto strictive actuators (MA).

11. The actuator assembly according to claim 7 or any claim dependent thereon, wherein the SMA array is provided as a thin film array configured to conform around a curvature of the body.

12. The actuator assembly according to claim 11, wherein the thin film comprises a clear coating or plastic film applied over the array of SMAs, wherein the clear coating or plastic film is arranged to translate actuation forces through its structure.

13. The actuator assembly according to any one of the preceding claims, wherein the first set of SMAs are connected in sequence along a first direction between first anchor zone and the second anchor zone.

14. The actuator assembly according to claim 13, wherein the first group of SMAs are formed in an array.

15. The actuator assembly according to claim 13 or 14, wherein the first group of SMAs further comprises at least a third set of SMAs having two further smart material actuator(s) (SMAs) connected in sequence between the first anchor zone and second anchor zone, wherein the third set of SMAs are connected in sequence along a third direction between first anchor zone and the second anchor zone, wherein the thirddirection is different from the first or second direction or in parallel with the first or second direction.

16. The actuator assembly according to claim 14 or 15, wherein the first, second or third set of SMAs of the first group of SMAs are formed in an array.

17. The actuator assembly according to claim 15 or 16, wherein the first set of SMAs of the first group of SMAs are arranged in a first layer, and the second set of SMAs of the first group of SMAs are arranged in a second layer, wherein the second layer at least partly overlaps the first layer.

18. The actuator assembly according to any one of the preceding claims, wherein the activation unit is releasably or fixedly attached to the support structure.

19. The actuator assembly according to any one of the preceding claims, wherein at least one of the SMAs is a photo-responsive actuator, and wherein the activation unit comprises a light source for transmitting light to activate said at least one SMA.

20. The actuator assembly according to claim 19, wherein the activation unit further comprises a light guide arranged to receive light from the said light source and direct said received light towards said at least one associated SMA.

21. The actuator assembly according to claim 19 or 20, wherein the activation unit comprises a Light Emitting Diode (LED) panel comprising at least one LED per SMA, wherein the one or more LEDs of the LED panel has a spatial configuration corresponding to that of the associated SMAs.

22. The actuator assembly according to any one of claims 19 to 21, wherein the activation unit comprises a flexible Light Emitting Diode (LED) panel comprising at least one LED per SMA, wherein the one or more LEDs of the flexible LED panel has a spatial configuration corresponding to that of the associated SMAs.

23. The actuator assembly according to any one of claims 19 to 22, wherein the activation unit comprises one or more LEDs attached to a flexible printed circuit board (PCB).

24. The actuator assembly according to any one of claims 19 to 23, wherein the activation unit comprises one or more groups of LEDs, each group of LEDs being arranged to activate one or more associated SMA(s) of the respective groups of SMAs.

25. The actuator assembly according to any one of the preceding claims, wherein the body is arranged to move in relation to the support structure upon activation or deactivation of at least one of the SMA(s).

26. The actuator assembly according to any of the preceding claims, further comprising a connector unit (40) attached to body (102), and arranged to connect to a further component.

27. The actuator assembly according to claim 26, wherein the further component is selected from the group comprising: an electronic device, an electromechanical device, mechanical device, a remote-controlled device, an aerospace component, a payload, a tool, a robotic member, and a control surface.

28. The actuator assembly according to any one of the preceding claims, wherein the body has a spherical, round, or oblong shape.

29. The actuator assembly according to any one of the preceding claims, wherein the support structure comprises a number of ball bearings supporting the body, thereby allowing the body to move or roll in relation to the support structure.

30. The actuator assembly according to any one of claims 1 to 28, wherein the support structure comprises a cone shaped portion, hollow pyramid shaped portion, cup shaped portion or socket portion, such as a ball bearing socket, for holding the body wherein the body has a shape corresponding to that of the socket portion.

31. The actuator assembly according to any one of the preceding claims, further comprising a second group of smart material actuators (SMA) connected between a further first anchor zone and a further second anchor zone.

32. The actuator assembly according to claim 31, wherein the second group of smart material actuators is at least partly oppositely arranged the first group of first smart material actuators, thereby forming a first agonist-antagonist SMA pair.

33. The actuator assembly according to claim 32, wherein the further second anchor zone of the second group of SMAs is oppositely arranged the second anchor zone of the first group of SMAs in relation to a first bisecting axis of the body.

34. The actuator assembly according to any one of claims 31 to 33, further comprising a third group of smart material actuators (SMA) connected between a further first anchor zone and a further second anchor zone, and a fourth group of smart material actuators (SMA) connected between a further first anchor zone and a further second anchor zone, wherein the third group of smart material actuators is at least partly oppositely arranged the fourth group of first smart material actuators, thereby forming second agonist-antagonist SMA pair.

35. The actuator assembly according to claim 34, wherein the further second anchor zone of the third group of SMAs is oppositely arranged the second anchor zone of the fourth group of SMAs in relation to a first bisecting axis of the body.

36. The actuator assembly according to any of the claims 31 to 35, further comprising a fifth group of smart material actuators (SMA) connected between a further first anchor zone and a further second anchor zone, and a sixth group of smart material actuators (SMA) connected between a further first anchor zone and a further second anchor zone, wherein the fifth group of smart material actuators is at least partly oppositely arranged the sixth group of smart material actuators, thereby forming third agonist-antagonist SMA pair.

37. The actuator assembly according to claim 36, wherein the further second anchor zone of the fifth group of SMAs is oppositely arranged the second anchor zone of the sixth group of SMAs in relation to a second bisecting axis (centre axis) of the body.

38. The actuator assembly according to claim 32 or 33, wherein the second anchor zone of the first group of SMAs is arranged 180 degrees offset the second anchor zone of the second group of SMAs along the body perimeter.

39. The actuator assembly according to claim 34 or 35, wherein the second anchor zone of the third group of SMAs is arranged 180 degrees offset the second anchor zone of the fourth group of SMAs along the body perimeter.

40. The actuator assembly according to claim 39, wherein the second anchor zone of the first group of SMAs is arranged 90 degrees offset the second anchor zone of the third group of SMAs along the body perimeter, and the second anchor zone of the second group of SMAs is arranged 90 degrees offset the second anchor zone of the fourth group of SMAs along the body perimeter.

41. The actuator assembly according to claim 34 or any claim dependent thereon, wherein the third agonist-antagonist SMA pair is arranged essentially orthogonal to the first agonist-antagonist SMA pair and the second agonist-antagonist SMA pair.

42. The actuator assembly according to any one of the preceding claims, wherein the respective second anchor zone is arranged on the exterior surface offset a second bisecting axis (centre axis) of the body, thereby allowing for tangent pull.

Images