Device and method for assisting movement of a body part

Abstract

An assistive device for assisting the movement of an articulating body part. The assistive device may comprise a soft pneumatic actuator configured to assist the movement of the articulating body part. The assistive device is configured such that, in use: a first phase of a movement of the body part is one of: assisted or not assisted by the assistive device; and a second phase of the movement of the body part is the other of: not assisted or assisted by the assistive device.

Description

[0001] Device and Method for Assisting Movement of a Body Part

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to the field of assistive devices, for assisting the movement of a body part, and their methods of use. Preferred embodiments relate to the field of assistive devices for use in rehabilitative therapy.

[0004] BACKGROUND OF THE INVENTION

[0005] Assistive and rehabilitative devices comprising actuators are known. For example, Panagiotis, P. et al (2015) ‘Soft robotic glove for combined assistance and at-home rehabilitation’, Robotics and Autonomous Systems, Vol 73, p135-143 discloses a soft robotic glove designed to augment hand rehabilitation for individuals with functional grasp pathologies. A single hydraulic (water) pump was used to actuate five multi-segment soft hydraulic actuators. Hydraulic power supply and supporting electro-mechanical components, including mechanical switches for manual control and a water reservoir, were integrated into a waist belt pack. An electromagnetic tracking system, external to the soft robotic glove, was employed to track hand position.

[0006] A soft robotic glove for assistance and rehabilitation of hand impaired patients is disclosed by H. K. Yap et al (2017) ‘A Fully Fabric-Based Bidirectional Soft Robotic Glove for Assistance and Rehabilitation of Hand Impaired Patients’, IEEE Robotics and Automation Letters, Vol 2, No 3, p1383-1390. The soft robotic glove is designed to assist hand impaired patients in rehabilitation exercises and in performing activities of daily living. Basic ‘control modes’ are proposed by H. K. Yap et al, wherein an actuator(s) is activated constantly during an assisted hand motion.

[0007] The present inventors have found a solution to shortcomings in the state of the art.

[0008] PROBLEM TO BE SOLVED BY THE INVENTION

[0009] It is an object of the invention to provide an improved assistive device and methods of use thereof. Although not limited to therapeutic applications, one object of the invention is to provide an improved assistive device for use in therapy and improved methods of therapy.For example, it is an object of the invention to provide an assistive device that is adaptive (during use) to the abilities of a given user. In a further example, it is an object of the invention to provide an assistive device that can record performance metrics and / or track improvement (or regression) in the performance of a movement over time.

[0010] SUMMARY OF THE INVENTION

[0011] In a first aspect, there is provided an assistive device for assisting the movement (e.g. a pre-defined movement) of an articulating body part, the assistive device configured such that, in use: a first phase of a movement of the body part is one of: assisted or not assisted by the assistive device; and a second phase of the movement of the body part is the other of: not assisted or assisted by the assistive device, wherein the first phase transitions to the second phase when: the movement of the body part, ora proxy thereof, reaches or passes a motion and / or force threshold; and / or a pre-defined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the body part.

[0012] In a second aspect, there is provided a method of assisting the movement of an articulating body part using an assistive device, the method comprising a first phase and a second phase, wherein: the first phase of a movement of the body part is one of: assisted or not assisted by the assistive device; and the second phase of the movement of the body part is the other of: not assisted or assisted by the assistive device, wherein the first phase transitions to the second phase when: the movement of the body part, ora proxy thereof, reaches or passes a motion and / or force threshold; and / or a pre-defined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the body part. Preferably, the assistive device is the assistive device of the first aspect.

[0013] In a third aspect, there is provided a controller configured (a) for use in the assistive device of the first aspect and / or (b) to perform the method of the second aspect or of the fourth aspect, as a component of an assistive device. Where the context allows, any feature or combination of features disclosed in relation to the first and second aspects may be incorporated into this third aspect.

[0014] In a fourth aspect, there is disclosed a method of determining, inferring or estimating the unassisted range of motion (or strength) and / or the assisted range of motion (or strength) of an articulating body part, using the assistive device of the first aspect. In a preferred embodiment of the fourth aspect, there is disclosed a method of determining, inferring orestimating if there is a potential for improvement in the unassisted range of motion (or strength) of an articulating body part through therapy, using the assistive device of the first aspect.

[0015] Features of said method and preferred method of the fourth aspect are disclosed in further detail below in relation to the first aspect and second aspect.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 illustrates one example of an assistive device;

[0018] Figures 2Ato 2F illustrate gas pressure (as a proxy for movement of fingers of a hand) of a pneumatic actuator over time, in relation to hand position;

[0019] Figure 3 illustrates one example of gas pressure (as a proxy for movement of a body part) over time; and

[0020] Figure 4 illustrate a flow chart for one embodiment of the invention.

[0021] DETAILED DESCRIPTION OF THE INVENTION

[0022] In accordance with the first aspect, there is provided an assistive device for assisting the movement (e.g. a pre-defined movement) of an articulating body part, the assistive device configured such that, in use: a first phase of a movement of the body part is one of: assisted or not assisted by the assistive device; and a second phase of the movement of the body part is the other of: not assisted or assisted by the assistive device, wherein the first phase transitions to the second phase when: (during the first phase) the movement of the body part, or a proxy thereof, reaches or passes a motion and / or force threshold; and / or a pre-defined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the body part.

[0023] In accordance with the second aspect, as set out in full in the summary above, there is provided a method of assisting the movement of an articulating body part using an assistive device, the method comprising a first phase and a second phase. Below, features are disclosed in the context of the configuration of the assistive device of the first aspect; however, to avoid repetition and where the context allows, the disclosed features are also incorporated into the method of the second aspect.

[0024] One advantage of the assistive device (and the corresponding method) is that it interacts with unassisted (also known as ‘active’) motion and facilitates assisted (also known as ‘passive’) motion during the same movement of an articulating body part. As such, the assistivedevice can gather more information in relation to the underlying abilities of a user during a movement and / or there are several options for (e.g. dynamically) tailoring the level of assistance provided to a user during a movement.

[0025] Preferably, the assistive device is for rehabilitative therapy of an articulating body part. For example, the assistive device is for improving any one or any combination of: the unassisted (also known as ‘active’) range of motion of the body part, the assisted (also known as ‘passive’) range of motion of the body part, the strength (or force) of the body part, the speed (or angular velocity) of the body part, the endurance of the body part, and the functionality (e.g. the ability to perform tasks, such as gripping tasks) of the body part. For example, by functionality of the body part, it is meant the ability of the body part to perform activities of daily living, e.g.: grooming (such as oral hygiene, hand washing, face washing, and / or shaving), dressing, eating (including, for example, drinking), bathing, and toileting. In addition or alternatively, the assistive device is configured to determine or infer if any of the aforementioned characteristics may be improved and, optionally, to what degree. For example, the assistive device is for manual rehabilitative therapy (also known as manipulative therapy), e.g. without the need for a medical professional. In one option, the assistive device herein may be referred to as a therapeutic device. It is typical for a medical professional, such as a physiotherapist, to manually manipulate a body part to perform manual therapy on that body part. An advantage of the assistive device is that the assistive device (as opposed to a medical professional) manually manipulates the body part.

[0026] However, the assistive device may be used in other applications (as described in more detail below). As such, optionally, the assistive device is not for rehabilitative therapy.

[0027] In a first option, the assistive device is configured such that, in use: the first phase of the movement of the body part is not assisted by the assistive device; and the second phase of the movement of the body part is assisted by the assistive device. In this first option, preferably, the first phase transitions to the second phase when the unassisted movement of the body part, ora proxy thereof, reaches (or passes) a motion and / or force threshold.

[0028] In a second option, the assistive device is configured such that, in use: the first phase of the movement of the body part is assisted by the assistive device; and the second phase of the movement of the body part is not assisted by the assistive device. In this second option, preferably, the first phase transitions to the second phase when the assisted movement of the body part, ora proxy thereof, reaches (or passes) a motion and / or force threshold.Herein, the phrase ‘reaches or passes a threshold’ is used. For example, a measurable parameter (e.g. pressure, such as gas pressure, or force) may increase and thus reach or exceed an upper threshold. In another example, a measurable parameter may decrease and thus reach or drop below a lower threshold.

[0029] Preferably, in both the first option and the second option above, the first phase may also transition to the second phase when a pre-defined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the articulating body part.

[0030] Preferably, the first phase transitions to the second phase when: (a) the movement of the body part, or a proxy thereof, reaches or passes a motion and / or force threshold; or (b) a pre-defined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the body part, whichever option (e.g. of options (a) and (b)) is the first to occur. Therefore, option (b) may be considered a time out. Preferably, the first phase transitions to the second phase when: the movement of the body part, ora proxy thereof, reaches or passes a motion and / or force threshold; or, if the threshold has not yet been reached or passed, when a pre-defined time out is triggered.

[0031] Preferably, the movement of the body part repeats (or loops) at least once. Thus, preferably, the first phase begins (for a second time) after or when the second phase ends.

[0032] Preferably, therefore, the assistive device is configured to assist repetitions of the movement of the articulating body part. Preferably, the assistive device configured such that, in use: sets of the first phase followed by the second phase are repeated.

[0033] In one option, once the second phase of a first repetition ends, the first phase of a second repetition begins after a pre-defined break period of time. In another option, once the second phase of a first repetition ends, the body part resets to a starting position before the first phase of a second repetition begins.

[0034] Optionally, the motion and / or force threshold is a dynamic threshold that may vary between repetitions of the movement of the body part (e.g. repetitions of the same session). For example, the dynamic threshold may increase or decrease with respect to the dynamic threshold of a previous (e.g. immediately previous) repetition based on the performance of the (e.g. unassisted) movement of the body part during the previous repetition. To further this example, if the performance of the (e.g. unassisted) movement of the body part during the previous repetition was good, the dynamic threshold may change in the subsequent repetition to increase difficulty(e.g. during the first phase). Similarly, in the same example, if the performance of the (e.g. unassisted) movement of the body part during the previous repetition was poor, the dynamic threshold may change in the subsequent repetition to decrease difficulty (e.g. during the first phase). For example, if the dynamic threshold is an unassisted range of motion threshold, increasing the threshold will require a greater degree of unassisted movement which increases difficulty. Similarly, the pre-defined period of time may, across repetitions, be a dynamic predefined period oftime that varies between repetitions.

[0035] The assistive device is for assisting the movement of an articulating body part. Preferably, the articulating body part is a human body part. Preferably, the articulating body part comprises one or more joints (or articulations) or is attached to a second body part ata connecting joint (or at a connecting articulation). Preferably, the assistive device is for assisting the articulating body part to (i) move about its joint(s), and / or (ii) move relative to a second body part (e.g. about a connecting joint or articulation).

[0036] Typically, the amount of movement of an articulating body part can be measured by angle (or degree), e.g. with respect to a joint or a group of joints. The measurement may be absolute (or an estimation thereof) or may be relative. For example, the amount of movement of an articulating body part may be measured as a percentage, e.g. a range of motion of from 0% to 100%. In one option, the amount of movement of an articulating body part may be assigned a score (e.g. a score out of five or out of ten). For example, a maximum displacement of the body part preferably means the body part has moved to a position that corresponds with 100% range of motion being attained. Generally, the term displacement means the articulating body part has moved to a given position.

[0037] Preferably, the assistive device assists the movement of an articulating body part in anyone or any combination of the following ways: (a) by increasing the unassisted (also known as ‘active’) range of motion of the movement; (b) by increasing the assisted (also known as ‘passive’) range of motion of the movement; (c) by increasing or decreasing the speed (e.g. or angular velocity) of the movement; (d) by increasing the strength (or force) of the movement; (e) by improving the functionality (e.g. the ability to perform tasks, such as gripping tasks) of the movement; and (f) by increasing the endurance of the movement, e.g. when the movement is repeated a plurality of times.

[0038] For example, with respect to option (f) above, the range of motion, the speed, and / or the strength of the movement may be generally the same as for unassisted movement,however, the assistive device provides a portion of the energy (or work) required to achieve that same level, e.g. the underlying body part does less work to achieve the same outcome. This may have both therapeutic and non-therapeutic applications.

[0039] In a further example, the assistive device is for augmenting the movement of an articulating body part. In this example, the assistive device may be for increasing the strength of a movement or for increasing the endurance of a movement (e.g. when the movement is performed repetitively, such as during manual labour). This is one example of non-therapeutic assistance.

[0040] Preferably, the articulating body part may be an arm or a portion thereof. For example, the articulating body part may be a shoulder, an elbow, a wrist, or a hand (or a portion thereof), or any combination thereof. Optionally, the articulating body part may be a leg or a portion thereof. For example, the articulating body part may be a hip, a knee, an ankle, or a foot (or a portion thereof), or any combination thereof. In still further examples, the articulating body part is the neck or the torso (e.g. movement of the spine). Where the context allows, the articulating body part may be (or the assistive device may be configured to assist) any combination of two or more body parts set out above.

[0041] More preferably, the articulating body part is a hand or a portion(s) thereof.

[0042] Herein, the five digits of a hand will be referred to as fingers.

[0043] Preferably, the articulating body part comprises at least one finger of a hand and, optionally, the wrist corresponding with the hand.

[0044] Preferably, the movement of the articulating body part is: flexion and / or extension; abduction and / or adduction; circumduction; elevation and / or depression; internal / medial rotation and / or external / lateral rotation; dorsiflexion and / or plantar flexion; pronation and / or supination; inversion and / or eversion; protrusion / protraction and / or retrusion / retraction; or opposition and / or reposition, depending on the articulating body part.

[0045] More preferably, the movement of the body part is: extension and / or flexion; or abduction and / or adduction.

[0046] The movement of an articulating body part comprising, or otherwise moving about, a single joint or articulation may be measured using a single angle. For example, a goniometer may be used to measure such an angle. In such cases, the displacement of an articulating body part may be represented by a given angle and the speed of an articulating body part may be represented by angular velocity.The movement of an articulating body part moving about two or more joints or articulations may be measured in several ways. For example, the angles (of each joint or articulation) may be averaged. In another example, the change in angle between one point (e.g. a knuckle) and another (e.g. opposite) point (e.g. the fingertip) of the articulating body part may be measured, despite there being more than one joint / articulation therebetween.

[0047] In a still further example, irrespective of the number of joints / articulations about which an articulating body part moves, it may not be necessary to measure (or estimate) a parameter of the movement of the articulating body part as such, such as angle. For example, a dimensionless quantity may be used to estimate or infer relative change in range of motion, e.g. gas pressure measurements may be used to estimate or infer relative progression or regression of, for example, range of motion over sequential uses of the assistive device.

[0048] Preferably, the movement of the body part is extension and / or flexion of the hand, more preferably of the fingers of a hand. In one option, the movement of the body part is extension and / or flexion of at least one finger of a hand and, optionally, extension and / or flexion of the wrist corresponding with the hand. For example, the movement of the body part is extension and / or flexion of any one or any combination of: the index finger, the middle finger, the ring finger, the little finger, and the thumb. For example, the movement of a body part is extension and / or flexion of the carpometacarpal, metacarpophalangeal and / or interphalangeal joints of the hand. In this example, in one option, the movement of a body part further includes extension and / or flexion of the scaphotrapeziotrapezoidaljoint (e.g. of the wrist).

[0049] Preferably, the movement of the articulating body part in the first phase and in the second phase is in the same direction (and / or is a continuous movement). Preferably, the movement of the articulating body part in the second phase is a continuation of the movement of the articulating body part in the first phase. More preferably, the movement of the articulating body part, the movement comprising the first phase and the second phase, is a single continuous movement. For example, in the first phase, a maximum unassisted range of motion (or maximum unassisted displacement) is attained and, in the second phase, a maximum assisted range of motion (or maximum assisted displacement) is attained, wherein the maximum assisted range of motion is greater than the maximum unassisted range of motion.

[0050] In an alternative option, the movement of the articulating body part in the second phase is in an alternative direction to the movement of the articulating body part in the first phase. More preferably, in this option, the movement of the articulating body part in the second phase isin an opposite (or reverse) direction to the movement of the articulating body part in the first phase. For example, in this option, the movement of the articulating body part in the first phase is extension and the movement of the articulating body part in the second phase is flexion, or vice versa.

[0051] Preferably, as discussed in further detail below, the assistive device comprises an actuator(s) configured (and / or positioned) to assist the movement of the articulating body part. Preferably, the actuator is a pneumatic actuator, for example a soft pneumatic actuator. As such, herein, reference to gas pressure is preferably reference to the gas pressure of the pneumatic actuator(s), which is described more fully below.

[0052] The gas pressure of the pneumatic actuator(s) may be a proxy for the movement of the articulating body part. For example, gas pressure may be a proxy for the displacement of the articulating body part and the rate of change of gas pressure may be a proxy for speed (e.g. or angular velocity) of the articulating body part.

[0053] Preferably, the first phase comprises a limit that constrains (or comprises limits that constrain) the movement of the articulating body part during the first phase. Preferably, the movement of the articulating body part during the first phase is limited by a first phase constraint(s).

[0054] Preferably, the second phase comprises a limit that constrains (or comprises limits that constrain) the movement of the articulating body part during the second phase.

[0055] Preferably, the movement of the articulating body part during the second phase is limited by a second phase constraint(s).

[0056] Preferably, the movement of the articulating body part stops (and / or the second phase ends) on reaching the limit / the second phase constraint.

[0057] Preferably, a limit that constrains the movement of the articulating body part (or a phase constraint) is a gas pressure limit (or constraint), e.g. an upper gas pressure limit. For example, on reaching a gas pressure limit / constraint, the pneumatic actuator(s) is not pressurised any further.

[0058] Optionally, both the first phase and the second phase each have a limit that constrains (or comprise limits that constrain) the movement of the articulating body part during the respective phases.

[0059] Preferably, the movement of the articulating body part may be constrained or limited: physically, or by providing an instruction or warning.Preferably, a limit that constrains the movement of the articulating body part during a phase is: a range of motion limit, a force limit, or a speed (e.g. angular velocity) limit. For example, a limit may be an upper limit or a lower limit. Preferably, a limit that constrains the movement of the articulating body part may be a gas pressure limit, including a limit for the rate of change of gas pressure.

[0060] As discussed above, the first phase and / or the second phase may (each) have two or more limits that constrain the movement of the articulating body part. For example, the first phase and / or the second phase may (each) have a lower limit and an upper limit for the same parameter. For example, the first phase and / or the second phase may (each) have two upper limits for different parameters (e.g. displacement and speed).

[0061] Preferably, a phase (e.g. the first phase or the second phase) of a movement of the articulating body part that comprises a limit or limits for constraining the movement is a phase that is assisted by the assistive device. This is because, for example, the displacement and / or speed (among other parameters) of an actuator(s) configured to assist the movement may be controlled / constrained.

[0062] However, optionally, a phase (e.g. the first phase or the second phase) of a movement of the body part that comprises a limit or limits for constraining the movement is a phase that is not assisted by the assistive device. For example, the assistive device may comprise a means (e.g. a second actuator) for counteracting or resisting the movement of the articulating part. Continuing this example, if the movement of the articulating body part is flexion the assistive device may comprise an extension actuator that may resist the flexion movement of the articulating body part.

[0063] In yet another example, the assistive device may be configured to give a warning (e.g. audible, visual, and / or haptic) that the limit(s) is approaching or has been reached. In this example, alternatively or in addition, the assistive device may be configured to give an instruction (e.g. audible, visual, and / or haptic) not to exceed the limit(s) when approaching the limit or once the limit has been reached.

[0064] In one option, if the first phase comprises a limit that constrains (or comprises limits that constrain) the movement of the articulating body part during the first phase, the first phase cannot transition to the second phase unless the / a limit is reached first. In this option, a limit may also be a target. For example, the limit (and / or target) may be a maximum gas pressure limit.In a first preferred embodiment, there is an assistive device, wherein, in use: a first phase of the movement of the body part is not assisted by the assistive device; and a second phase of the movement of the body part is assisted by the assistive device, the second phase comprising a limit that constrains (or limits that constrain) the movement of the articulating body part during the second phase,

[0065] wherein the first phase transitions to the second phase when: the unassisted movement of the body part, or a proxy thereof, reaches (or passes) a motion and / or force threshold; and / or a pre-defined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the body part.

[0066] Preferably, the movement of the articulating body part stops (and / or the second phase ends) on reaching the / a limit. Preferably, the second phase comprises a range of motion limit that constrains the movement (or displacement) of the articulating body part during the second phase. More preferably, the second phase comprises a (e.g. upper) gas pressure limit. Preferably, the assistive device comprises a pneumatic actuator(s) configured to assist the movement of the articulating body part. Preferably, during the second phase, the pneumatic actuator(s) may not exceed a pre-defined gas pressure limit (e.g. which gas pressure limit is a proxy for a given displacement of the articulating body part).

[0067] In a second preferred embodiment, there is an assistive device, wherein, in use: a first phase of the movement of the articulating body part is assisted by the assistive device, the first phase comprising a limit that constrains (or limits that constrain) the movement of the articulating body part during the first phase; and a second phase of the movement of the body part is not assisted by the assistive device,

[0068] wherein the first phase transitions to the second phase when:

[0069] the assisted movement of the body part, or a proxy thereof,

[0070] reaches (or passes) a motion and / or force threshold;

[0071] the assisted movement of the body part reaches the / a limit or

[0072] constraint; and / or

[0073] a pre-defined period of time has elapsed since beginning, or

[0074] since an instruction was provided to begin, the movement of the body part.

[0075] Preferably, the first phase comprises a range of motion limit that constrains the movement of the articulating body part during the first phase. More preferably, the first phase comprises a (e.g. upper) gas pressure limit. Preferably, the assistive device comprises apneumatic actuator(s) configured to assist the movement of the articulating body part.

[0076] Preferably, during the first phase, the pneumatic actuator(s) may not exceed a pre-defined gas pressure limit (e.g. which gas pressure limit is a proxyfor a given displacement of the articulating body part).

[0077] Optionally, the first phase cannot transition to the second phase unless the / a limit is reached first (e.g. an upper gas pressure limit). For example, the first phase cannot transition to the second phase unless the / a limit is reached first, and subsequently the assisted movement of the body part, or a proxy thereof, reaches (or passes) a motion and / or force threshold.

[0078] For example, the movement of the articulating body part in the first assisted phase is extension. The movement of the articulating body part is assisted until an extension range of motion limit is reached. Subsequently, a motion threshold is reached or passed, the motion threshold indicative of the start of a (e.g. reverse) flexion movement of the articulating body part. As such, the first phase transitions to the second phase. As the first phase transitions to the second phase, a pneumatic actuator of the assistive device may vent to atmosphere. Therefore, in the second phase, the unassisted movement of the body part may be flexion.

[0079] Directly above, a first and second preferred embodiment have been described. Where the context allows, any features disclosed herein may be incorporated into said first and second preferred embodiments.

[0080] Preferably, the second phase directly follows (or begins directly after) the first phase. Preferably, the second phase immediately follows (or begins immediately after) the first phase. Preferably, the transition from the first phase to the second phase is an instant transition.

[0081] For example, if the assistive device comprises an actuator(s) configured to assist the movement of the articulating body part, the actuation begins or ends (e.g. the actuator is turned on or off) when the second phase begins.

[0082] Preferably, the movement of the articulating body part, the movement comprising the first phase and the second phase, is a single continuous movement, e.g. a single continuous movement in the same direction.

[0083] Optionally, the transition from the first phase to the second phase comprises a pause or a delay for a pre-defined period of time (e.g. before the second phase begins). For example, the pause or delay may be a rest period or a hold period as part of a therapeutic regime.As discussed above, the first phase may transition to the second phase when: the movement of the body part, ora proxy thereof, reaches (or passes) a motion and / or force threshold, (e.g. before a time out is triggered).

[0084] Preferably, the first phase transitions to the second phase when the movement of the articulating body part, or a proxy thereof, reaches or passes any one or any combination of: (a) a range of motion threshold (e.g. which may also be referred to as a displacement threshold); (b) a speed (or angular velocity) threshold; and / or (c) a force threshold.

[0085] Preferably, the range of motion threshold is an upper range of motion threshold. For example, the first phase transitions to the second phase when the movement of the articulating body part, or a proxy thereof, reaches or exceeds an upper range of motion threshold. For example, the upper range of motion threshold may be a maximum unassisted displacement of the body part, e.g. a user using the assistive device may have moved their body part as far as possible without assistance during the first phase. In an alternative example, the upper range of motion threshold may be a maximum assisted displacement of the body part. A maximum displacement may correspond to the articulating body part position at 100% range of motion.

[0086] As discussed herein, the proxy for the movement of the articulating body part may be gas pressure (of a pneumatic actuator). Preferably, the range of motion threshold is a gas pressure threshold. The gas pressure threshold may be an upper gas pressure threshold or a lower gas pressure threshold. For example, depending on the circumstance, a movement of an articulating body part in a given direction may increase or decrease an inner volume of a pneumatic actuator, decreasing or increasing the gas pressure (when the amount of gas is fixed) respectively.

[0087] Preferably, the speed (or angular velocity) threshold is a lower speed (or angular velocity) threshold. For example, the first phase transitions to the second phase when the movement of the body part, or a proxy thereof, reaches or drops below a lower speed (or angular velocity) threshold. For example, the lower speed (or angular velocity) threshold may be zero (or approaching zero), e.g. a user using the assistive device may no longer be moving their articulating body part because they have moved their body part as far as possible without assistance during the first phase. Optionally, however, the speed (or angular velocity) threshold is an upper speed (or angular velocity) threshold.

[0088] Preferably, the speed (or angular velocity) threshold is a threshold for the rate of change of gas pressure. For example, an upper or a lower rate of change of gas pressurethreshold. For example, as the speed (or angular velocity) of a movement of an articulating body part reaches or approaches zero, the rate of change of gas pressure may correspondingly reach or approach zero.

[0089] In another option, the range of motion threshold and / or the speed (or angular velocity) threshold may be indicative of the start or the beginning of a movement of the articulating body part.

[0090] As illustrated in Figure 3 below, in one option the transition from the first phase to second phase may not occur until the movement of the body part (or a proxy thereof) has continuously reached (or passed) the motion and / or force threshold for a pre-defined period of time (which maybe referred to as the threshold period of time). Therefore, optionally, if the motion and / or force threshold is reached or passed momentarily, but that degree of movement of the articulating body part has not been maintained for the pre-defined threshold period of time, the transition to the second phase will not yet occur.

[0091] Preferably, the first phase transitions to the second phase when the movement of the articulating body part reaches a maximum unassisted displacement (e.g. if the movement is unassisted in the first phase) or a maximum assisted displacement (e.g. if the movement is assisted in the first phase). For example, a maximum displacement means the articulating body part has reached a position corresponding to 100 % range of motion (ROM) (or a user has moved their body part as far as possible).

[0092] For example, particularly for unassisted movement, when the articulating body part stops moving or slows down significantly (e.g. the speed or angular velocity of the movement of the articulating body part reaches zero or approaches zero), this may indicate that a maximum displacement has been reached. In a still further example, if there is an inflection in the direction of movement of the articulating body part, this may indicate that a maximum displacement has been reached; this is because on reaching the maximum displacement it may not be possible to hold the body part in the maximum displacement position and as such the body part begins to move in a direction opposite to the intended direction. It is discussed above how the rate of change of gas pressure may be used to infer if the movement of the articulating body has stopped (or is close to stopping).

[0093] Preferably, the assistive device is configured to estimate or infer the unassisted range of motion (or strength) of the articulating body part based on the movement of the body part, or on a proxy thereof (e.g. change in gas pressure), during the unassisted phase.Preferably, the assistive device is configured to estimate or infer progression and / or regression of the unassisted range of motion (or strength) of the articulating body part based on the movement of the body part, or on a proxy thereof (e.g. change in gas pressure), during the unassisted phase of sequential uses of the assistive device over time. In one example, the assistive device is configured to measure relative progression and / or regression of the unassisted range of motion (or strength) of the body part based on the movement of the body part, or on a proxy thereof (e.g. change in gas pressure), during the unassisted phase of sequential uses of the assistive device overtime.

[0094] Preferably, the assistive device is configured to estimate or infer the assisted range of motion (or strength) of the body part based on the movement of the body part, or on a proxy thereof (e.g. change in gas pressure), during the assisted phase.

[0095] Preferably, the assistive device is configured to estimate or infer progression and / or regression of the assisted range of motion (or strength) of the body part based on the movement of the body part, or on a proxy thereof (e.g. change in gas pressure), during the assisted phase of sequential uses (e.g. sequential sessions) of the assistive device over time. In one example, the assistive device is configured to measure relative progression and / or regression of the assisted full range of motion (or strength) of the body part based on the movement of the body part, or on a proxy thereof (e.g. change in gas pressure), during the assisted phase of sequential uses of the assistive device overtime.

[0096] More generally, it is preferred that the assistive device is configured to estimate or infer progression or regression of a user’s (or the articulating body part’s): unassisted range of motion (or strength) of the body part; and / or assisted range of motion (or strength) of the body part, based on sequential uses of the assistive device over time.

[0097] For example, the sequential uses (e.g. sequential sessions) may be separated by at least 6 hours, preferably at least 12 hours, still more preferably at least 24 hours. For example, the sequential uses may be three or more sequential uses, more preferably four or more sequential uses, still more preferably five or more sequential uses.

[0098] For example, the assistive device may be calibrated (either generally or to a specific user) to generate a dataset that correlates gas pressure (or any other suitable parameter, dependent on the assistive device) to the displacement (e.g. bending angle) of the articulating body part. Similarly, in one option, the assistive device may be calibrated (either generally or to a specific user) to generate a dataset that correlates rate of change of gas pressure (or any othersuitable parameter, dependent on the assistive device) to the speed (e.g. angular velocity) of the articulating body part.

[0099] Preferably, the assistive device is configured to determine or infer if there is a potential for improvement in the unassisted range of motion (or strength) of the body part through therapy, e.g. by completing a future session(s) of therapy. For example, by continuing to use the assistive device in a future session(s) of therapy.

[0100] For example, if the maximum assisted range of motion is larger than the maximum unassisted range of motion, this may indicate that the unassisted range of motion may be improved further, e.g. there is room for improvement in the range of motion of the body part.

[0101] Preferably, the assistive device is configured to determine or infer a user’s ability to perform activities of daily living that correspond with the movement of the body part.

[0102] Preferably, the assistive device is configured to determine or infer progression or regression of a user’s ability to perform activities of daily living that correspond with the movement of the body part, based on sequential uses of the assistive device over time. Preferably, the assistive device is configured to determine or infer if there is a potential for improvement in a user’s ability to perform activities of daily living, that correspond with the movement of the body part, through therapy, e.g. by completing a future session(s) of therapy. Activities of daily living are described more fully above.

[0103] Preferably, the assistive device is configured to provide an instruction or an alert (or a notification): (a) to begin moving the body part; (b) that the first phase is transitioning or has transitioned to the second phase; (c) that the second phase is complete (or has ended); and / or (d) to stop moving the body part.

[0104] For example, the assistive device may be configured to provide an instruction to begin moving the body part, e.g. at the beginning of an unassisted phase (or the first phase).

[0105] In one option, the assistive device is configured to first provide an instruction to move the articulating body part to a pre-defined position, such as a closed-grip (or fist or clenched) position, e.g. if the articulating body part is a hand.

[0106] For example, the assistive device may be configured to provide an alert that the assistive device will begin (or has begun) or will stop (or has stopped) providing assistance. For example, the assistive device may be configured to provide an instruction to continue moving the body part, e.g. even if assistance provided by the assistive device has begun or stopped.In one option, the assistive device is configured to provide an instruction to temporarily stop (or pause) moving the body part, e.g. during a transition between the first phase and second phase. In a further option, the assistive device may be configured to provide an instruction to move the body part in an alternative (e.g. opposite or reverse) direction, e.g. at the beginning of the second phase.

[0107] For example, the assistive device may be configured to provide an instruction to stop moving the body part, e.g. at the end of the second phase or when a phase limit or constraint is reached.

[0108] Preferably, the instruction or alert (or notification) is any one or any combination of: verbal / audible, visual, and haptic.

[0109] Preferably, the assistive device comprises a progress and / or performance indicator during the first phase and / or the second phase. For example, the progress and / or performance indicator may be benchmarked against a target for a movement parameter (e.g. a target displacement, speed, or force). Preferably, the progress and / or performance indicator is any one or any combination of: verbal / audible, visual, and haptic.

[0110] Preferably, the assistive device comprises at least one (one or more) sensors configured to measure or track the movement of the body part or a proxy thereof. For example, the at least one sensors may be any one or any combination of: flex sensors; strain sensors; force sensors; camera-based (or visual) sensors; pressure sensors, including gas pressure sensors; and gas flow rate sensors.

[0111] Preferably, the assistive device is configured to provide an assistive force to the articulating body part.

[0112] Preferably, the assistive device comprises an actuator(s) configured (and / or positioned) to assist the movement of the articulating body part. The actuator(s) may be any suitable type of actuator. Optionally, the actuator(s) may be any one or any combination of two or more (where the context allows) of pneumatic, hydraulic, electric, magnetic, thermal, and mechanical.

[0113] Preferably, the actuator(s) is configured to actuate, assist and / or resist the movement of the articulating body part. Preferably, the actuator(s) is a bending actuator (e.g. the actuator is configured to move in a bending trajectory) or is a straightening actuator.Preferably, the assistive device is configured such that the actuator(s) conforms with (or generally moves with or maintains generally the same position of) the articulating body part as it moves. On example is illustrated in Figure 1.

[0114] Preferably, the actuator(s) is a fluid power actuator, more preferably a pneumatic actuator(s), still more preferably a soft pneumatic actuator(s).

[0115] The assistive device may comprise a single actuator or plural actuators. Herein, where the context allows, reference to a single actuator is also reference to a plurality of actuators, and vice versa.

[0116] Preferably, a soft pneumatic actuator comprises an actuator body. Preferably, a soft pneumatic actuator (or the actuator body of a soft pneumatic actuator) comprises an internal chamber (or chambers). Preferably, a soft pneumatic actuator (or the actuator body of a soft pneumatic actuator) comprises an actuator wall. Preferably, the actuator wall encloses the internal chamber (or chambers).

[0117] Preferably, the soft pneumatic actuator is an inextensible and / or inelastic soft pneumatic actuator. An inextensible and / or inelastic soft pneumatic actuator generally does not stretch as it (e.g. as its internal chamber) is pressurised with a gas. As an inextensible and / or inelastic soft pneumatic actuator is inflated / pressurised it may move or displace as described below, for example due to the geometry of the actuator.

[0118] An inextensible and / or inelastic soft pneumatic actuator preferably has an actuator body that comprises an inextensible material, such as an inextensible sheet material. Examples of inextensible materials include plastic fabrics, e.g. nylon-based or polyester-based fabrics, such as knitted fabrics. Inextensible materials may optionally be coated with thermoplastic, such that the material is generally gas impermeable.

[0119] Preferably, an inextensible and / or inelastic soft pneumatic actuator comprises two strips or sheets of inextensible sheet material attached to each other and forming a cavity therebetween. In one option, an airtight bladder may be inserted into the cavity. In a second option, the inextensible sheet material is inherently airtight and the cavity itself acts as an airtight bladder (or inner chamber).

[0120] Example inextensible soft pneumatic actuators, comprising flexible thermoplastic polyurethane-coated fabrics, are disclosed by H. K. Yap et al (2017) ‘A Fully Fabric-Based Bidirectional Soft Robotic Glove for Assistance and Rehabilitation of Hand Impaired Patients’, IEEE Robotics and Automation Letters, Vol 2, No 3, p1383-1390.Optionally, the soft pneumatic actuator is an extensible and / or elastic soft pneumatic actuator. In this option, the soft pneumatic actuator (or the actuator body, or an actuator wall of the actuator body) comprises a resilient (e.g. elastic) and / or ‘soft’ material.

[0121] Preferably, at least a portion or portions of the actuator body is / are configured to expand and / or contract when an inner chamber(s) of the soft pneumatic actuator is pressurised / depressurised. Expansion and / or contraction of the actuator body causes the soft pneumatic actuator to move, preferably in a predefined trajectory, such as described below.

[0122] Preferably, a soft pneumatic actuator may move by lengthening, shortening, straightening, bending, twisting, widening, narrowing or any combination of two or more thereof. For example, a soft pneumatic actuator may move in a predefined bending, twisting, extending, shortening, extend-twisting or bend-twisting trajectory.

[0123] Herein, reference to pressurising or depressurising a pneumatic actuator (e.g. a soft pneumatic actuator) preferably means increasing the pressure or decreasing the gas pressure, respectively, of an internal chamber of the pneumatic actuator (e.g. by operating a gas pump or venting to atmosphere). Herein, reference to measuring gas pressure of a pneumatic actuator preferably means measuring gas pressure of an internal chamber thereof. Herein, reference to a pneumatic actuator being in fluid communication with a gas pump preferably means an internal chamber of the pneumatic actuator is in fluid communication with the gas pump.

[0124] Preferably, a soft pneumatic bending actuator bends when it is pressurised and straightens (and optionally bends in an opposite direction) when it is depressurised, or vice versa. Preferably, a soft pneumatic actuator is configured to bend to correspond to flexion movement of an articulating body part, such as of a digit or digits of a hand.

[0125] Preferably, a soft pneumatic straightening actuator straightens when it is pressurised and becomes flexible (or non-rigid) when it is depressurised. Preferably, the soft pneumatic actuator is configured to straighten to correspond to extension movement of an articulating body part, such as a digit or digits of a hand.

[0126] Preferably, the soft pneumatic actuator is configured to have a range of motion corresponding to the range of motion of a digit or digits of a hand. Preferably, the hand is a human hand.Preferably, the actuator body is elongate (i.e. has a generally elongate shape). Preferably, the actuator body is sized for positioning on top (i.e. on the dorsal side) of a digit or digits of a hand.

[0127] Preferably, the actuator body has a length of at least 5 cm, more preferably at least 7 cm, for example at least 9 cm. Preferably, the actuator body has a length of at most 20 cm, more preferably at most 18 cm, still more preferably at most 16 cm, for example at most 14 cm. Preferably, the actuator body has a length of from 5 cm to 20 cm, more preferably from 7 cm to 18 cm, still more preferably from 9 cm to 16 cm, for example around 12 cm.

[0128] Preferably, the actuator body has a width of at least 0.5 cm, more preferably at least 1 cm, still more preferably at least 1.5 cm, for example at least 2 cm. Preferably, the actuator body has a width of at most 6 cm, more preferably at most 5 cm, still more preferably at most 4 cm, for example at most 3 cm. Preferably, the actuator body has a width of from 0.5 cm to 6 cm, more preferably from 1 cm to 5 cm, still more preferably from 1.5 cm to 4 cm, most preferably from 2 to 3 cm, for example around 2.5 cm.

[0129] Preferably, the actuator body has a height of at least 0.5 cm, more preferably at least 1 cm, e.g. at least 1.5 cm. Preferably, the actuator body has a height of at most 5 cm, more preferably at most 4 cm, still more preferably at most 3 cm, for example at most 2 cm.

[0130] Preferably, the actuator body has a height of from 0.5 cm to 4 cm, more preferably from 1 cm to 3 cm, for example from 1.5 cm to 2 cm, e.g. of 1.7 mm.

[0131] Preferably, the actuator body is configured to be straight and / or flexible (e.g. may flex with any degree of freedom) when the internal chamber is at atmospheric pressure.

[0132] The soft pneumatic actuator (preferably, the internal chamber of the actuator body) is preferably in fluid communication with a gas pump. In one option, the soft pneumatic actuator is in fluid communication with a gas pump manifold which is in turn in fluid communication with a gas pump.

[0133] Preferably, a conduit, such as a hose or tube, fluidly connects the soft pneumatic actuator and a gas pump. Preferably, the conduit is flexible. An example conduit is an air hose.

[0134] Preferably, the device further comprises a pressure sensing means for measuring gas pressure of (e.g. inside) a pneumatic actuator. More preferably, the pressure sensing means is for measuring gas pressure of an internal chamber of a pneumatic actuator. Preferably, the pressure sensing means is in fluid communication with the pneumatic actuator. More preferably, the pressure sensing means is in fluid communication with the internal chamber of a pneumaticactuator body. For example, the pressure sensing means may be in fluid communication with a conduit fluidly connecting the pneumatic actuator and a gas pump (e.g. the conduit is a branched conduit). In one option, a conduit fluidly connectingthe pneumatic actuator and a gas pump comprises a junction, such as a T-junction, in fluid communication with the pressure sensing means.

[0135] Preferably, the pressure sensing means is configured to measure pressures above and / or below ambient atmospheric pressure (e.g. above and / or below 1 atm). Preferably, the pressure sensing means is configured to measure gauge pressure. In one option, the pressure sensing means comprises an absolute pressure sensor. In a further option, the pressure sensing means comprises a differential pressure sensor. In a still further option, the pressure sensing means comprises two absolute pressure sensors or an absolute pressure sensor and a barometric pressure sensor. Where the pressure sensing means comprises two absolute pressure sensors, it is preferred that a first absolute pressure sensor is configured to measure positive gauge pressure and a second absolute pressure sensor is configured to measure negative gauge pressure.

[0136] Preferably, the assistive device is a wearable device. Preferably, the assistive device may be donned and doffed. Preferably, the assistive device is a glove or glove-like wearable device. For example, the wearable device may be worn as an exoskeleton, e.g. worn in relation to the articulating body part.

[0137] As discussed above, it is preferred that the assistive device comprises a fluid power actuator(s) (preferably, a soft pneumatic actuator(s)) configured (and / or positioned) to assist the movement of the articulating body part.

[0138] In one preferred embodiment, there is provided an assistive device, the assistive device comprising a fluid power actuator(s) configured (and / or positioned) to assist the movement of the articulating body part, wherein, in use: a first phase of the movement of the body part is not assisted by the assistive device; and a second phase of the movement of the body part is assisted by the assistive device, wherein the first phase transitions to the second phase when: the gas pressure of the fluid power actuator(s) reaches (or passes) a gas pressure threshold; and / or a pre-defined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the body part. For example, where a fluid power actuator(s) is configured in relation to an articulating body part, the gas pressure of the fluid power actuator(s) may be a proxy for a characteristic of the movement of the articulatingbody part (as discussed more fully herein). For example, the gas pressure of the fluid power actuator(s) may be a proxy for the displacement or position of the articulating body part.

[0139] Where the context allows, any feature or combination of features disclosed herein may be incorporated into the preferred embodiment set out directly above. Further, the following features are disclosed in relation to the preferred embodiment directly above as well as in relation to the first and second aspects generally.

[0140] Preferably, the proxy for the movement of the articulating body part is the gas pressure of the pneumatic actuator(s).

[0141] Preferably, the first phase transitions to the second phase when the gas pressure of the actuator(s) reaches or passes any one or any combination of: (a) a gas pressure threshold, e.g. a lower gas pressure threshold or an upper gas pressure threshold; and (b) a threshold for the rate of change of gas pressure, e.g. a lower rate of change of gas pressure threshold or an upper rate of change of gas pressure threshold.

[0142] Preferably, the assistive device is configured to partially pressurise (e.g. ‘prime’) the pneumatic actuator(s), more preferably the soft pneumatic actuator(s). For example, an amount of gas is put into an inner chamber of the pneumatic actuator. Preferably, partially pressurising the pneumatic actuator (generally) does not affect the articulating body part, e.g. (generally) does not affect the displacement of the articulating body part.

[0143] Preferably, partial pressurisation (or ‘priming’) occurs before an instruction is provided to begin moving the body part and / or before the first phase begins. Partial pressurisation is discussed in further detail below.

[0144] As discussed above, in a second aspect of the invention there is provided a method of assisting the movement of an articulating body part using an assistive device. To avoid repetition, features disclosed above in the context of the configuration of the assistive device of the first aspect may be formulated as method features of the second aspect. Further features of the second aspect are disclosed below.

[0145] Preferably, the method comprises the step of providing an assistive device of the first aspect. Preferably, the method comprises the step of donning (and, optionally, of doffing) the assistive device.

[0146] The invention will now be described in more detail, without limitation, with reference to the accompanying figures. Features common throughout the figures share reference numbers.In Figure 1 , there is shown (in part) an assistive device 1 worn on a hand 3. As illustrated, the assistive device 1 is worn in a glove-like manner. The assistive device 1 comprises a plurality of inextensible soft pneumatic actuators 7 and 17. Soft pneumatic actuator 7 corresponds with a thumb (not shown) of the hand 3. Each of four soft pneumatic actuators 17 correspond with the remaining fingers 5 of the hand 3. Each soft pneumatic actuator 7 and 17 is independently in fluid communication with a pressurised air source 19, typically a gas pump (not shown). A pressure sensor(s) (not shown) may also be in fluid communication with the soft pneumatic actuators 7 and 17, e.g. the pressure sensor(s) in communication with a controller (not shown) for controlling the pressurised air source 19.

[0147] A flexible (e.g. fabric) liner 15 is located on the dorsal side of the hand 3. The tip of each of fingers 5 are inserted into thimbles 21 of the flexible liner 15. The actuators 7 and 17 are attached to the flexible liner 15 using pop studs 9 proximalto the thimbles 21. Straps 11 and 13 of the flexible liner 15 wrap around the hand 3 and the actuators 17 to keep the actuators 17 secured in place on the dorsal side of the hand 3.

[0148] It is understood that the actuators 7 and 17 will straighten and bend in correlation with their corresponding underlying fingers.

[0149] The soft pneumatic actuators 7 and 17 each have an inner chamber (not shown). When the inner chambers are at ambient pressure (or are not inflated) they are flexible; thus, the soft pneumatic actuators 7 and 17 may conform to the shape of the fingers 5 and thumb (not shown), even if the fingers 5 and thumb are bent (or clenched), as is typical for a hand with spasticity.

[0150] The inner chambers of the soft pneumatic actuators 7 and 17 may be inflated partially and still conform to any bending of the fingers 5 and thumb (not shown). However, when the inner chambers (not shown) reach a given air pressure, the soft pneumatic actuators 7 and 17 begin to straighten; as such, the soft pneumatic actuators 7 and 17 may be used to extend (or assist the extension of) the underlying fingers 5 and thumb (not shown).

[0151] The assistive device 1 illustrated in Figure 1 is an example of how an actuator(s) may be configured to assist the movement of an articulating body part. However, as set out above, any suitable actuator may be used and the articulating body part is not limited to the fingers of the hand.

[0152] Figures 2Ato 2F illustrate how, in the case an inextensible soft pneumatic actuator(s) (e.g. as illustrated in Figure 1 ) is used to assist the movement of an articulating bodypart, the gas pressure of the soft pneumatic actuator(s) maybe used as a proxy for the movement of the body part. In each of Figures 2A to 2F a hand is shown to demonstrate hand position, however, an assistive device is not shown on the hand.

[0153] In this example, the four actuators 17 of Figure 1 may be considered to be in fluid communication with each other and thus to have a common gas pressure. Whereas actuator 7, which corresponds with the thumb, is not in fluid communication with the four actuators 17 and the thumb is moved separately; thus, the gas pressure of actuator 7 is not illustrated in Figures 2A to2F.

[0154] In Figure 2A, at time A, the hand is in a clenched position, which is typical for a person with spasticity of the hand.

[0155] Optionally, the device may be configured to provide an instruction to fully clench the hand as a preliminary step, e.g. in case the hand is not naturally in a fully clenched position. Therefore, the position of the hand will be in a (generally) consistent starting position between uses of the assistive device. In an alternative option, a preliminary calibration step maybe performed to determine, estimate, or infer the starting position of the hand.

[0156] The soft pneumatic actuator is then partially inflated between time A and time A’. At time A’, pressurisation of the inner chamber of the soft pneumatic actuator ceases and the amount of gas in the inner chamber is maintained. This is necessary to provide the inner chamber of the inextensible soft pneumatic actuator with a starting volume. However, the pressure of the soft pneumatic actuator does not increase to such an extent as to affect the position of the fingers of the hand. This step maybe called priming or pre-inflating the soft pneumatic actuator.

[0157] Some pneumatic actuators (including some soft pneumatic actuators) have an inner chamber volume at ambient pressure. For example, soft pneumatic actuators comprising an elastic body typically have an inner chamber having a volume at ambient pressure. In these cases, the step of priming the soft pneumatic actuator may be optional.

[0158] In Figure 2B, at time B, the pressure of the soft pneumatic actuator has stabilised. The pressure of the soft pneumatic actuator at time B may be referred to as a bias pressure.

[0159] At time B, the soft pneumatic actuator is bent because it conforms with the shape of the corresponding finger(s). However, if the soft pneumatic actuator is straightened its inner chamber volume will increase and thus the pressure of the soft pneumatic actuator will drop.At time B, a target pressure (Target P) is calculated, e.g. by a controller in communication with appropriate pressure sensors. For example, the target pressure may be the bias pressure minus a pre-defined difference in pressure (AP).

[0160] Finally, also at time B, an instruction is provided to begin extending the fingers of the hand.

[0161] Figure 2C illustrates a dorsal view of a hand (with no corresponding graph). In Figure 2C, the thumb has been moved away (e.g. by actuator 7 in Figure 1 ) from the remaining fingers by pressurising actuator 7. Therefore, the thumb will not interfere with the movement of the remaining fingers. This step may happen prior to time A (see Figure 2A) or at any point before time B (see Figure 2B).

[0162] When the instruction to begin extending the fingers of the hand (e.g. not including the thumb) has been given, the soft pneumatic actuators that correspond with the fingers also begin to straighten. As discussed above, as the soft pneumatic actuators straighten their inner chamber volumes increase and thus their pressure drops.

[0163] As such, it can be seen that the target pressure corresponds with a given displacement (or degree of extension) of the fingers of the hand. The lower the target pressure (i.e. the larger the AP) the greater the degree of extension that is required to reach or exceed the target pressure. It follows, therefore, that the target pressure is a motion threshold (corresponding to displacement) for the movement of the fingers of a hand.

[0164] In Figure 2D, at time D (see the solid curved line), the target pressure is reached and therefore the transition to phase two of the movement is triggered. In Figure 2D, in the picture of the hand, the hand has opened around halfway; this may represent a maximum unassisted range of motion.

[0165] In another example of Figure 2D (see the dashed curved line), the target pressure is not reached; rather, a time out is reached first which triggers the transition to phase two of the movement. This time out example will not be continued in the Figures below because phase 2 is the same in either case.

[0166] In Figure 2D, two examples are illustrated that trigger the transition to the second phase, reaching a gas pressure threshold and a time out, respectively. However, a still further trigger may be reaching or passing a rate of change of gas pressure threshold. For example, around time D, it can be seen that the rate of change of gas pressure falls to zero. This may indicate that the maximum unassisted range of motion has been reached because the movementof the fingers has stopped. Thus, a given rate of change of gas pressure is a motion threshold (corresponding to the speed of displacement) for the movement of the fingers of a hand.

[0167] Phase 1 of the movement may therefore be from time B (see Figure 2B) to either time D or D’ (see Figure 2D). Phase 1 transitions to phase 2 are either time D or D’, dependent on the unassisted movement of the underlying fingers of the hand.

[0168] In the second phase of the movement, the gas pressure of the soft pneumatic actuator(s) is increased upto a maximum pressure (MaxP), as illustrated in Figure 2E. The maximum pressure is a limit that constrains the movement of the articulating body part during the second phase. The maximum pressure maybe selected to avoid over-extension of the fingers beyond a safe assisted range of motion for a user. As the pressure of the soft pneumatic actuator(s) increases the actuator(s) straighten and thus the finger(s) of the hand also straighten.

[0169] Finally, as shown in Figure 2F, the fingers of the hand are held fora pre-defined period of time in the assisted extended position before the gas in the soft pneumatic actuator(s) is vented, allowing the fingers of the hand to relax back to the clenched position.

[0170] In Figure 3, it is illustrated that the transition to the second phase (in one option) may not occur until a motion threshold has been reached or passed for a continuous period of time 23.

[0171] An implementation of the invention has been demonstrated with reference to the fingers of a hand (as an articulating body part) and soft pneumatic actuators (configured to assist the movement of the body part). However, the invention may also be applied to other body parts as described above. Furthermore, a wide array of pneumatic and non-pneumatic actuators may be configured to assist the movement of articulating body parts.

[0172] Figure 4 is a flowchart illustrating one implementation of the invention. Steps marked with an Asterix are optional steps. As illustrated by arrow 25, when the second phase ends, the method optionally repeats or loops, e.g. for a pre-defined number of repetitions. In the flowchart of Figure 4, for simplicity, the time out (pre-defined period of time) is not illustrated.

[0173] Further aspects and / or embodiments of the invention are described in the following clauses. Where the context allows, features of any one or any combination of the clauses below may be incorporated into any one of the aspects set out above.

[0174] Clause 1. An assistive device for assisting the movement of an articulating body part, the assistive device configured such that, in use: a first phase of a movement of the bodypart is one of: assisted or not assisted by the assistive device; and a second phase of the movement of the body part is the other of: not assisted or assisted by the assistive device, wherein the first phase transitions to the second phase when: the movement of the body part, or a proxy thereof, reaches (or passes) a motion or force threshold; and / or a pre-defined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the body part.

[0175] Clause 2. The assistive device according to clause 1 , wherein, in use: the first phase of the movement of the body part is not assisted by the assistive device; and the second phase of the movement of the body part is assisted by the assistive device,

[0176] wherein the first phase transitions to the second phase when: the unassisted movement of the body part, or a proxy thereof, reaches (or passes) a motion or force threshold; and / or a predefined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the body part.

[0177] Clause 3. The assistive device according to clause 1 or clause 2 for use in rehabilitative therapy.

[0178] Clause 4. An assistive device according to any one of the preceding clauses, the assistive device comprising an actuator(s) configured to assist the movement of the articulating body part.

[0179] Clause 5. An assistive device according to any one of the preceding clauses, wherein the movement of the articulating body part is: extension and / or flexion; or abduction and / or adduction.

[0180] Clause 6. An assistive device according to any one of the preceding clauses, wherein the articulating body part is a hand or a portion thereof.

[0181] Clause 7. An assistive device according to any one of the preceding clauses, wherein the movement of the articulating body part in the first phase and in the second phase is in the same direction.

[0182] Clause 8. An assistive device according to any one of clauses 1 to 6, wherein the movement of the articulating body part in the second phase is in an alternative direction to the movement of the articulating body part in the first phase.

[0183] Clause 9. An assistive device according to any one of the preceding clauses, wherein the first phase comprises a limit (or a stop) that constrains (or comprises limits that constrain) the movement of the articulating body part during the first phase.

[0184] - 1 -Clause 10. An assistive device according to any one of the preceding clauses, wherein the second phase comprises a limit (or a stop) that constrains (or comprises limits that constrain) the movement of the articulating body part during the second phase.

[0185] Clause 11. An assistive device according to any one of the preceding clauses, wherein the second phase immediately follows (or begins immediately after) the first phase.

[0186] Clause 12. An assistive device according to any one of the preceding clauses, wherein the transition from the first phase to the second phase is an instant transition.

[0187] Clause 13. An assistive device according to any one of the preceding clauses, wherein the movement of the body part, the movement comprising the first phase and the second phase, is a single continuous movement.

[0188] Clause 14. An assistive device according to any one of clauses 1 to 11 , wherein the transition from the first phase to the second phase comprises a pause or a delay (e.g. in movement) fora pre-defined period of time.

[0189] Clause 15. An assistive device according to any one of the preceding clauses, wherein the first phase transitions to the second phase when the movement of the body part, or a proxy thereof, reaches or passes any one or any combination of: (a) a range of motion threshold, preferably reaches or exceeds an upper range of motion threshold; (b) a speed (or angular velocity) threshold, preferably reaches or falls below a lower speed (or angular velocity) threshold; and / or (c) a force threshold.

[0190] Clause 16. An assistive device according to any one of the preceding clauses, wherein the first phase transitions to the second phase when the movement of the body part reaches a maximum unassisted displacement or a maximum assisted displacement.

[0191] Clause 17. An assistive device according to any one of the preceding clauses, wherein the device is configured to estimate or infer the unassisted full range of motion of the body part based on the movement of the body part, or on a proxy thereof, during the unassisted phase.

[0192] Clause 18. An assistive device according to any one of the preceding clauses, wherein the device is configured to estimate or infer the assisted full range of motion of the body part based on the movement of the body part, or on a proxy thereof, during the assisted phase.

[0193] Clause 19. An assistive device according to any one of the preceding clauses, wherein the device is configured to estimate or infer progression or regression of the user’s: unassisted range of motion of the body part; and / or assisted range of motion of the body part, based on sequential uses of the assistive device overtime.Clause 20. An assistive device according to any one of clauses 3 to 19, wherein the assistive device is configured to determine or infer if there is a potential for improvement in the unassisted range of motion of the body part through therapy, e.g. by using the assistive device in a future session(s) of therapy.

[0194] Clause 21. An assistive device according to any one of the preceding clauses, wherein the assistive device is configured to provide an instruction or an alert: (a) to begin moving the body part; (b) that the first phase is transitioning or has transitioned to the second phase; (c) that the second phase is complete (or has ended); (d) to stop moving the body part.

[0195] Clause 22. An assistive device according to any one of the preceding clauses, the assistive device comprising a soft pneumatic actuator(s) configured to assist the movement of the articulating body part.

[0196] Clause 23. An assistive device according to clause 22, wherein the proxy for the movement of the articulating body part is the gas pressure of the soft pneumatic actuator(s).

[0197] Clause 24. An assistive device according to clause 22 or clause 23, wherein the first phase transitions to the second phase when the gas pressure of the actuator(s) reaches or passes any one or any combination of: (a) a gas pressure threshold, e.g. a lower gas pressure threshold or an upper gas pressure threshold; and (b) a threshold for the rate of change of gas pressure, e.g. a lower rate of change of gas pressure threshold or an upper rate of change of gas pressure threshold.

[0198] Clause 25. An assistive device according to any one of clauses 22 to 24, wherein the assistive device is configured to partially pressurise (e.g. prime) the soft pneumatic actuator(s), preferably before an instruction is provided to begin moving the body part.

[0199] Clause 26. An assistive device according to any one of the preceding clauses, wherein the assistive device is a wearable device.

[0200] Clause 27. An assistive device according to any one of the preceding clauses, wherein the movement of the body part repeats at least once.

[0201] Clause 28. An assistive device according to clause 27, wherein the motion or force threshold is a dynamic threshold that varies dependent on the performance of the movement of the body part in a previous repetition; and / or wherein the pre-defined period of time is a dynamic pre-defined period of time that varies dependent on the performance of the movement of the body part in a previous repetition.The invention has been described with reference to preferred embodiments. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention.

Claims

CLAIMS:

1. An assistive device for assisting the movement of an articulating body part, wherein the assistive device comprises a soft pneumatic actuator(s) configured to assist the movement of the articulating body part, and wherein the assistive device is configured such that, in use:a first phase of a movement of the body part is one of: assisted or not assisted by the assistive device; anda second phase of the movement of the body part is the other of: not assisted or assisted by the assistive device,wherein the first phase transitions to the second phase when:the movement of the body part, or a proxy thereof,reaches (or passes) a motion or force threshold; and / ora pre-defined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the body part.

2. The assistive device as claimed in claim 1 , wherein, in use:the first phase of the movement of the body part is not assisted by the assistive device; andthe second phase of the movement of the body part is assisted by the assistive device,wherein the first phase transitions to the second phase when:the unassisted movement of the body part, or a proxy thereof, reaches (or passes) a motion or force threshold; and / ora pre-defined period of time has elapsed since beginning, or since an instruction was provided to begin, the movement of the body part.

3. The assistive device as claimed in claim 1 or claim 2 for use in rehabilitative therapy.

4. An assistive device as claimed in any one of the preceding claims, the assistive device comprising an actuator(s) configured to assist the movement of the articulating body part.

5. An assistive device as claimed in any one of the preceding claims, wherein the movement of the articulating body part is: extension and / or flexion; or abduction and / or adduction.

6. An assistive device as claimed in any one of the preceding claims, wherein the articulating body part is a hand or a portion thereof.

7. An assistive device as claimed in any one of the preceding claims, wherein the movement of the articulating body part in the first phase and in the second phase is in the same direction.

8. An assistive device as claimed in any one of claims 1 to 6, wherein the movement of the articulating body part in the second phase is in an alternative direction to the movement of the articulating body part in the first phase.

9. An assistive device as claimed in any one of the preceding claims, wherein the first phase comprises a limit (or a stop) that constrains (or comprises limits that constrain) the movement of the articulating body part during the first phase.

10. An assistive device as claimed in any one of the preceding claims, wherein the second phase comprises a limit (or a stop) that constrains (or comprises limits that constrain) the movement of the articulating body part during the second phase.

11. An assistive device as claimed in any one of the preceding claims, wherein the second phase immediately follows (or begins immediately after) the first phase.

12. An assistive device as claimed in any one of the preceding claims, wherein the transition from the first phase to the second phase is an instant transition.

13. An assistive device as claimed in any one of the preceding claims, wherein the movement of the body part, the movement comprising the first phase and the second phase, is a single continuous movement.

14. An assistive device as claimed in any one of claims 1 to 11 , wherein the transition from the first phase to the second phase comprises a pause or a delay (e.g. in movement) fora pre-defined period of time.

15. An assistive device as claimed in any one of the preceding claims, wherein the first phase transitions to the second phase when the movement of the body part, or a proxy thereof, reaches or passes any one or any combination of:(a) a range of motion threshold, preferably reaches or exceeds an upper range of motion threshold;(b) a speed (or angular velocity) threshold, preferably reaches or falls below a lower speed (or angular velocity) threshold; and / or(c) a force threshold.

16. An assistive device as claimed in anyone of the preceding claims, wherein the first phase transitions to the second phase when the movement of the body part reaches a maximum unassisted displacement or a maximum assisted displacement.

17. An assistive device as claimed in any one of the preceding claims, wherein the device is configured to estimate or infer the unassisted full range of motion of the body part based on the movement of the body part, or on a proxy thereof, during the unassisted phase.

18. An assistive device as claimed in any one of the preceding claims, wherein the device is configured to estimate or infer the assisted full range of motion of the body part based on the movement of the body part, or on a proxy thereof, during the assisted phase.

19. An assistive device as claimed in any one of the preceding claims, wherein the device is configured to estimate or infer progression or regression of the user’s: unassisted range of motion of the body part; and / or assisted range of motion of the body part, based on sequential uses of the assistive device overtime.

20. An assistive device as claimed in any one of claims 3 to 19, wherein the assistive device is configured to determine or infer if there is a potential for improvement in the unassisted range of motion of the body part through therapy, e.g. by using the assistive device in a future session(s) of therapy.

21. An assistive device as claimed in any one of the preceding claims, wherein the assistive device is configured to provide an instruction or an alert:(a) to begin moving the body part;(b) that the first phase is transitioning or has transitioned to the second phase; (c) that the second phase is complete (or has ended);(d) to stop moving the body part.

22. An assistive device as claimed in any one of the preceding claims, wherein the proxy for the movement of the articulating body part is the gas pressure of the soft pneumatic actuator(s).

23. An assistive device as claimed in any one of the preceding claims, wherein the first phase transitions to the second phase when the gas pressure of the actuator(s) reaches or passes any one or any combination of:(a) a gas pressure threshold, e.g. a lower gas pressure threshold or an upper gas pressure threshold; and(b) a threshold for the rate of change of gas pressure, e.g. a lower rate of change of gas pressure threshold or an upper rate of change of gas pressure threshold.

24. An assistive device as claimed in any one of the preceding claims, wherein the assistive device is configured to partially pressurise (e.g. prime) the soft pneumatic actuator(s), preferably before an instruction is provided to begin moving the body part.

25. An assistive device as claimed in any one of the preceding claims, wherein the assistive device is a wearable device.

26. An assistive device as claimed in any one of the preceding claims, wherein the movement of the body part repeats at least once.

27. An assistive device as claimed in claim 26, wherein the motion or force threshold is a dynamic threshold that varies dependent on the performance of the movement of the body part in a previous repetition; and / or wherein the pre-defined period of time is a dynamic pre-defined period of time that varies dependent on the performance of the movement of the body part in a previous repetition.

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