IT202100009095A1 - WEARABLE DEVICE FOR PHYSICAL REHABILITATION AND METHOD FOR ITS CONTROL - Google Patents

Description

Description of the Industrial Invention entitled:

?WEARABLE DEVICE FOR PHYSICAL REHABILITATION AND METHOD FOR ITS CONTROL?

DESCRIPTION

The present invention refers to a wearable device for physical rehabilitation and to a method for controlling said device; in particular, for the physical rehabilitation of a person who has suffered bone or neurological trauma.

As ? Known, the rehabilitation process of a person who has suffered a shoulder joint injury begins with a passive mobilization of the upper limb, during which the patient? totally passive and driven by one or more? therapists along specific trajectories (?Three upper limb robot devices after stroke rehabilitation: a review and clinical perspective,? in Neuro Rehabilitation, vol 33, pp. 3-11, 2013). After this phase, we proceed with assisted active mobilization, in which the patient is able to actively move his joint and is invited to carry out activities? simulations of daily life (the so-called ?occupational therapy?).

In conventional rehabilitation, both passive and assistive mobilizations of the patient are required of the therapist and, therefore, the therapist must perform intensive and repetitive tasks using their own physical strength.

Robotic exoskeletons for upper limb rehabilitation can relieve therapists from manual intervention, offering intense, repetitive and long-lasting mobilization, with significant benefits and effects from a rehabilitation point of view, such as improvement of joint excursion, circulation blood flow, nourishment and tissue remodeling, and more.

Researchers developed robotic exoskeletons with different types of kinematics, actuation and control, capable of performing passive and assisted mobilizations (

?Transfer of scientific concept on clinical practice: recent robot assisted training studies,? in Functional Neurology, vol. 25, pp. 173-177, 2009). However, there are still some limitations from the point of view of clinical efficacy, as active mobilization is ? limited to simple exercises since? existing devices require the patient to remain in a fixed position, typically sitting (

?Feasibility and safety of shared EEG/EOG and vision-guided autonomous whole-arm exoskeleton control to perform activities of daily living,? in Scientific Report, Vol. 8, no. 10823, 2018). The latter ? a considerable constraint on occupational therapy; in fact, the simulation of the activities? of daily life? dramatically limited and ? still far from representing a real-life scenario, as commercial exoskeletons are not intended to be mobile. Furthermore, it should be noted that, due to the complexity of the shoulder complex, right? available today a unique kinematic model for the upper limb at the state of the art of biomechanics. Pi? in detail, the shoulder complex (see fig. 1) ? made up of the glenohumeral joint GH and the shoulder girdle, where the latter includes the sternoclavicular, acromioclavicular and scapulothoracic joints ST. These joints are similar to joints which form a closed kinematic chain and which, therefore, cannot move independently, for example the displacement of the humerus leads to the movement of the shoulder girdle. The so-called scapulohumeral rhythm? the kinematic interaction between the humerus and the scapula, the coupling of which changes with the tasks to be performed, planes of elevation and angles; moreover, it also changes according to the observed subject (

?Preliminary results of online classification of upper limb motions from around-shoulder muscle activities,? in IEEE International Conference on Rehabilitation Robotics (ICORR), pp. 1-6, 2011). For example, as shown in FIG. 2, in the first phase of abduction (from 0? to 30?), the movement takes place mainly at the level of the GH joint, while an abduction of 180? can? be obtained through a rotation of about 120? of the joint GH and 60? of rotation of the ST joint, therefore with a ratio of 2:1.

In the American patent application publication US 2016/0206497 A1 in the name an exoskeleton is described which does not restrict the mobility? of a person in an environment, but what for? does it not allow an effective recovery of the functionality? motor skills in people who have suffered a trauma to the shoulder joint; in fact, the configuration of the kinematic chain of this exoskeleton prevents you from reproducing the natural movements of the shoulder, thus reducing? its usefulness? therapy for this type of trauma.

The present invention proposes to solve these and other problems by providing a wearable device for physical rehabilitation.

Furthermore, the present invention proposes to solve these and other problems by also making available a method for controlling said wearable device for physical rehabilitation.

The idea behind the present invention ? to use a wearable device for rehabilitation (such as an exoskeleton) having a kinematic chain comprising at least five connecting elements (also known by the term ?arms? or ?link?) and at least four rotational joints (also known by the term of ?rotational joint?) which connect the connection elements together in a sequential manner, where the first and the fifth connection element are respectively shaped to couple to a portion of the back and to an arm of a person, and where the revolving joints are positioned as follows:

? the first rotational joint has an axis of rotation substantially parallel to a longitudinal axis of the first connection element and to a longitudinal axis of the second connection element;

? the second rotational joint has a rotation axis substantially orthogonal to the rotation axis of said first rotational joint;

? the third rotational joint has a rotation axis substantially orthogonal to the rotation axis of the second rotational joint and substantially parallel to a longitudinal axis of the fourth connection element;

? the fourth rotational joint has a rotation axis substantially orthogonal to the rotation axis of the third rotational joint and to a longitudinal axis of the fifth connection element.

This configuration of the connection elements and joints allows said device to assume a rest configuration in which the longitudinal axes of the first and fifth element are parallel to each other and, therefore, the device according to the invention assumes a ? inverted U?, allowing advantageously to facilitate coupling of the device according to the invention to the body of a person when he is in an upright position with the upper limb (which must undergo rehabilitation treatment) stretched along his side. It is highlighted, in fact, that said device can? be adapted to the size of a person's body simply by varying the length of the third connection element only (for example by replacing said third connection element or varying its length in the ways that will be better described hereinafter), before coupling the first connection element to said person's back and the fifth element to said person's arm.

The possibility? to use the device in an upright position, together with suitable control methods of the same which will be described in the continuation of this description, can? allow the patient to perform various exercises derived from occupational therapy in an at least partially automated manner. Furthermore, the configuration of the connection elements and of the joints of the device according to the invention allows, when the device is coupled to a person's body, to keep most of the device's components out of the subject's normal field of vision, thus allowing them to to concentrate better in carrying out occupational therapy.

Further advantageous characteristics of the present invention are the subject of the attached claims.

These characteristics and further advantages of the present invention will become clearer from the description of an embodiment thereof shown in the attached drawings, provided purely by way of non-limiting example, in which: ? fig. 1 illustrates in detail a human skeleton representing a shoulder;

? fig. 2 illustrates a scapulohumeral rhythm of a human shoulder;

? fig. 3 illustrates a wearable device for physical rehabilitation according to the invention in an operative condition; ? fig. 4 shows a representation of movements allowed by the device of fig. 3;

? fig. 5 schematically shows a kinematic chain included in the device of fig. 3.

Reference to "an embodiment" within this specification means that a particular configuration, structure, or feature is comprised in at least one embodiment of the invention. Thus, the terms "in one embodiment" and the like, found in different parts of this specification, do not necessarily all refer to the same embodiment. Furthermore, the particular configurations, structures or characteristics may be combined in any suitable way in one or more? forms of implementation. References used below are for convenience only. and they do not limit the scope or scope of the implementations.

With reference to fig. 3, will come now described a wearable device 1 for rehabilitation (such as an exoskeleton) according to the invention which comprises a first connection element E1, a second connection element E2, a third connection element E3, a fourth connection element E4 and a fifth connection element E5, where each of said connection elements E1-E5 has an elongated shape (for example cylindrical, prismatic or of another type), ie it has a longitudinal axis which crosses it along its entire length.

The first connection element E1 ? shaped so as to be bound to a portion of the back of a person P (to whom reference will also be made with the term ?patient?), for example by means of a strip of fabric comprising two Velcro portions which allow it, one once wrapped around the waist of the patient P, to be firmly bound to the back of said patient P, so? to advantageously unload a large part of the weight of the device 1 in the lower part of the spine, i.e. near the body's center of gravity, so as not to alter the patient's posture when wearing the device 1.

The fifth connection element E5 ? instead shaped so as to be constrained to a portion of an arm of the patient P, for example by means of a band of elastic fabric or Velcro, so? that the device 1 can exert force on the upper limb of the person so as to set it in motion.

Furthermore, said device 1 also comprises the following elements:

? a first rotational joint q1 which joins together the first E1 and the second connection element E2, and which has a rotation axis substantially parallel to a longitudinal axis of said first connection element E1 and to a longitudinal axis of said second connection element E2;

? a second rotational joint q2 which joins together the second E2 and the third connection element E3, and which has a rotation axis orthogonal to the rotation axis of said first rotational joint q1;

? a third rotational joint q3 which joins together the third E3 and the fourth connection element E4, and which has a rotation axis orthogonal to the rotation axis of the second rotational joint q2 and substantially parallel to a longitudinal axis of the fourth connection element E4 connection;

? a fourth rotational joint q4 which joins together the fourth E4 and the fifth connection element E5, and which has a rotation axis orthogonal to the rotation axis of the third rotational joint q3 and also to a longitudinal axis of the fifth connection element E5.

Each of said rotational joints q1-q4 preferably comprises an electric actuator comprising a permanent magnet or induction electric motor, an encoder (of the absolute or relative type) which generates a positioning signal, and a microcontroller configured to operate the motor on the basis of a reference angular position and of the positioning signal generated by said encoder, so that said joint reaches an angular position equal to the reference angular position.

It is highlighted that the reference angular position ? preferably encoded in a pulse-width modulation PWM signal or other protocol, where said signal ? transmitted to said microcontroller from a?unit? of control that will come? better described below.

When said device 1 ? in an operating condition, the first connection element E1 ? constrained to a portion of the patient's back and, therefore, the first joint q1 has the axis of rotation substantially parallel to the longitudinal axis of the body of said patient P, while the fifth connection element E5 ? bound to the arm (of said patient P) which must be moved by device 1.

This allows the device 1 to make the patient perform movements, without the need for continuous intervention by a therapist, who can therefore limit himself to helping the patient to wear the device 1 and subsequently supervise the rehabilitation session, intervening only in case of need?.

In this way, ? is it possible to automate at least part of the activity? rehabilitation and occupational therapy, giving the possibility? the patient to be in an upright position and to move freely in the space during the therapy.

How already? previously mentioned, the configuration of the joints q1-q4 and of the connection elements E1-E5 allows said device 1 to assume a rest configuration in which the longitudinal axes of the first and of the fifth element are substantially parallel to each other and, therefore , the device according to the invention assumes an ?upturned U? shape, allowing to advantageously facilitate coupling of the device 1 to the patient?s body who is in an upright position, with the upper limb (to be treated) extended along the side. In this position, device 1 can? be advantageously adapted to the size of the patient's body by replacing the third connection element with one of a different length.

As an alternative to what has just been described above, the third connection element E3 can be of type variable length, cos? to allow the therapist to advantageously adapt (manually or automatically) the length of the third connecting element to the size of the patient; in fact, the length of the connection element E3 ? function of the distance between the longitudinal axis of the patient's body and the longitudinal axis of an arm lying along the side. Pi? in detail, the third connection element E3 can? include a translational joint, such as a prismatic joint. This translational joint can be actuated manually, for example by unscrewing and screwing in a set screw and making said joint slide, or automatically, for example by means of an actuator, preferably of an electric, hydraulic or other type, controlled by the unit? control.

This allows the device 1 to adapt perfectly to the body of a patient regardless of his build, so that said device 1 is able to move the upper limb of a patient in a pre-established way and above all without causing pain or injury to the ligaments and muscles which could be greatly weakened by an extended period of inactivity, as occurs for example following a bone or neurological trauma of a certain importance.

In this way, ? is it possible to automate at least part of the activity? rehabilitation and occupational therapy, giving the possibility? the patient to be in an upright position and to move freely in the space during the therapy.

In combination or as an alternative to what is described above, the wearable device 1 preferably also comprises the following elements:

? a sixth connection element E6 shaped so as to be coupled to a forearm of the patient P, and preferably having an elongated shape;

? a fifth rotational joint q5 which connects the fifth E5 and the sixth connection element E6 to each other, and which preferably has a rotation axis substantially parallel to the longitudinal axis of the fifth connection element E5 and to a longitudinal axis of the sixth connection element E6.

This allows the device 1 to also make the patient's forearm perform movements, without the need for continuous intervention by a therapist, thus making more complete the rehabilitation therapy to which ? subjected the patient's upper limb.

In this way, ? Is it possible to automate an even greater part of the activity? rehabilitation and occupational therapy, giving the possibility? the patient to be in an upright position and to move freely in the space during the therapy.

The unit control can? for example be made up of a microcontroller of the type ESP32, ESP8266, or other, and include the following elements:

? means of control and / or processing (for brevity? also called CPU), such as one or more? CPU and/or a microcontroller and/or an FPGA and/or a CPLD and/or other, which are able to allow control of the wearable device 1, preferably in a programmable manner, by executing suitable instructions;

? memory means, such as for example a RAM random access memory and/or a memory of the Flash type and/or of other types, which are in signal communication with the control and/or processing means, and where in said means of at least the instructions which implement a control method of the device 1 according to the invention and which can be read by the control and/or processing means 11 when the wearable device 1 is preferably stored, are stored in the memory. in a working condition;

? input and/or output means (I/O) which are in communication with the rotational joints q1-q4 and possibly also with the fifth rotational joint q5 and/or with the translational joint included in the third connection element E3; moreover, said input/output means can for example be used to connect said wearable device 1 to a programming terminal configured to write instructions (which the CPU 11 will have to execute later) in the memory means and/or allow the diagnosis of any failures of said wearable device 1; such input/output means can for example comprise a USB, IEEE 1394, RS232, IEEE 1284, Ethernet, WiFi?, Bluetooth?, or other adapter;

? means of communication, preferably an interface that operates according to one of the standards of the family IEEE 802.3 (known as Ethernet), IEEE 802.11 (known as WiFi?) or 802.16 (known as WiMax?), LTE? or other, that allow the unit? for controlling the wearable device 1 to communicate with a mobile terminal (such as a smartphone), a tablet, a PC or the like;

? a communication bus which allows the exchange of information between the control and/or processing means, the memory means, the input/output means and the communication means.

As an alternative to the communication bus, ? It is possible to connect the control and/or processing means, the memory means, the input/output means and the communication means with a star architecture.

The control method of the device 1 according to the invention comprises the following steps:

? a reading step, in which, by means of the input means, first position data are acquired which define for each rotational joint q1-q4, an angular position in which said joint is located;

? a generation step, in which, by means of the control and/or processing means, second position data are determined on the basis of said first position data and therapy data which define a trajectory that the patient's upper limb must follow and /o a level of assistance that the device 1 must provide to the patient, where said second position data define for each rotational joint q1-q4, an angular position subsequent to the position in which said joint is found;

? a transmission step, in which the second position data is transmitted to the rotational joints q1-q4 by means of the output means.

It should be noted that the control method described above ? performed by the processing and/or control means in a cyclical manner, and ? useful for passively operating a patient's arm, i.e. a patient who, being at the beginning of his rehabilitation therapy, does not have the strength to move his arm.

In this way, ? is it possible to carry out the activity? of rehabilitation in an automatic way, giving possibility? the patient to be in an upright position and to move freely in the space during the therapy.

In addition to what has just been described above, it should be noted that the control method according to the invention can also support patients in a pi? advanced stage of recovery, i.e. when the wearable device 1 must assist a patient in a no longer? completely passive.

For this purpose, during the reading phase, movement data can be acquired by means of the input means which define, for each rotational joint q1-q4, its state of movement, i.e. its speed? and/or acceleration of rotation, the torque applied to it or other, and where during the generation phase, in which, by means of the control and/or processing means, the second position data on the base are generated, as well as the first position data, also of said movement data.

In this way, ? Is it possible to automate an even greater part of the activity? rehabilitation and occupational therapy, giving the possibility? the patient to move freely in space during therapy.

With reference also to fig. 4, the movements that the wearable device 1 will now be described, when ? in an operating condition, ? able to make the patient perform. Pi? in detail, the device 1 ? able to make the patient's arm perform abduction/adduction movements in the coronal (or frontal) plane of said patient's body P (see fig. 4(a)), and horizontal flexion/extension movements in the transversal plane, for example when the patient's arm is in the 90 abduction position? (see fig. 4(b)). These movements can be performed individually or in combination with each other, so to obtain the best possible combination for the patient.

To do this, the therapist can, using a supervisory device (such as a mobile terminal, a tablet, a PC, or other), set or vary the therapy data that define the movements (and their speed) that the device 1 must make the patient perform it; for this purpose, the wearable device 1 can? be configured to receive therapy data via communication media.

With reference also to fig. 5, when the device 1 has to perform (passively or in an assisted manner) the abduction/adduction movements of the patient's arm starting from a position lying along the side of said patient, the second rotational joint q2 and the fourth rotational joint q4 have advantageously their axes of rotation are substantially parallel to each other.

In addition to what has been described above, the processing and/or control means are preferably configured to generate (during the generation phase) the second position data relating to the second rotational joint q2 on the basis of the second position data relating to the fourth rotational joint q4.

Pi? in detail, the processing and/or control means can be configured to execute a set of instructions which implements the following relationship:

(1)

where represent the angular positions of the second q2 and the fourth rotational joint q4, respectively, while

? the parameter that defines the level of coupling between rotational joints q2 and q4.

The function can for example be defined as below:

(2)

Where ? a threshold angular value below which the ST scapulothoracic joint is not solicited, ie all the abduction or adduction movement ? performed by the glenohumeral joint GH

It should be noted that the parameter and possibly also the threshold parameter can be changed by the therapist via the supervision device during a physiotherapy session, so to stress the glenohumeral joint GH and the scapulothoracic joint ST in a different way. This turns out to be particularly important when you have to recover a fracture to one of these two joints, because? can you? make the joint that has undergone the trauma work advantageously in a differentiated manner according to the patient's state of recovery.

In this way it is possible to imitate in a more specifies the kinematics of the shoulder complex during abduction and adduction movements, exploiting the parallelism between the rotation axes of the q2,q4 joints.

Furthermore, when the device 1 has to make (passively or assisted) the horizontal flexion/extension movements of the patient's arm P, the first rotational joint q1 and the third rotational joint q3 have their rotation axes not perpendicular to each other or parallel to each other.

For this purpose, the processing and/or control means are preferably configured to generate (during the generation step) the second position data relating to the first rotational joint q1 on the basis of the second position data relating to the third rotational joint q3.

Pi? in detail, the processing and/or control means can be configured to execute a set of instructions which implements the following relationship:

(3)

where they represent the angular positions of the first q1 and the third rotational joint q3, respectively, while

? the parameter that defines the level of coupling between rotational joints q1 and q3.

The function can for example be defined as <below:>

(4) In this way, it is possible to imitate more effectively. specifies the kinematics of the shoulder complex during horizontal flexion/extension movements, exploiting the parallelism between the rotation axes of the q1 and q3 joints.

It is highlighted that the parameter pu? be varied by the therapist through the supervision device during a physiotherapy session, allowing the GH glenohumeral joint and the ST scapulothoracic joint of the patient to be stimulated differently during horizontal flexion/extension movements. This makes it possible to recover a fracture in one of these two joints, why? can you? make the joint that has undergone the trauma work advantageously in a differentiated manner according to the patient's state of recovery.

In this way, it is possible to imitate more effectively. specifies the kinematics of the shoulder complex during horizontal flexion/extension movements, exploiting the additional degree of freedom? That ? present in the situation of non-orthogonality? between the axes of rotation of the joints q1 and q3. This allows you to automate an even greater part of the activity? of rehabilitation and occupational therapy in the different stages of recovery of the patient, giving possibility? the patient to be in an upright position and to move freely in the space during the therapy.

Furthermore, this makes the inverse kinematic problem of the kinematic chain associated with the wearable device 1 easily solvable, i.e. calculating the angular positions of the joints q1-q4 knowing the lengths d1,d2,d3,d4,d5 of the connection elements E1-E5, and possibly also the length d6 of the sixth connection element E6 if present. Some of the possible variations have been described above, but ? it is clear to the person skilled in the art that, in the practical implementation, there are also other embodiments, with different elements which can be replaced by other technically equivalent ones. The present invention is not therefore limited to the illustrative examples described, but ? susceptible to various modifications, improvements, replacement of parts and equivalent elements without involving deviations from the basic inventive idea, as specified in the following claims.

Claims (13)

A wearable device (1) for physical rehabilitation of a person (P), comprising ? a first connection element (E1), a second connection element (E2), a third connection element (E3), a fourth connection element (E4) and a fifth connection element (E5), where each of said elements connection (E1-E5) has an elongated shape, where said first connection element (E1) ? shaped so as to be constrained to at least a portion of the back of said person, and where said fifth connection element (E5) ? shaped so that it can be attached to at least a portion of an arm of that person, characterized by the fact that it also includes ? a first rotational joint (q1) which joins together the first (E1) and the second connection element (E2), and which has a rotation axis parallel to a longitudinal axis of said first connection element (E1) and to a longitudinal axis of said second connection element (E2), ? a second rotational joint (q2) which joins together the second (E2) and the third connection element (E3), and which has a rotation axis orthogonal to the rotation axis of said first rotational joint (q1), ? a third rotational joint (q3) which joins together the third (E3) and the fourth connection element (E4), and which has a rotation axis orthogonal to the rotation axis of the second rotational joint (q2) and parallel to a ?longitudinal axis of the fourth connection element (E4), ? a fourth rotational joint (q4) which joins together the fourth (E4) and the fifth connection element (E5), and which has a rotation axis orthogonal to the rotation axis of the third rotational joint (q3) and to a? longitudinal axis of the fifth connection element (E5). 2. Device (1) according to claim 1, wherein the third connection element (E3) is variable length type. The device (1) according to claim 2, wherein the third connecting element (E3) comprises a translational joint. Device (1) according to any one of claims 1 to 3, also comprising ? a sixth connection element (E6) shaped so as to be able to be coupled to a forearm of said person (P), and ? a fifth rotational joint (q5) which connects the fifth (E5) and the sixth connection element (E6) to each other. 5. Device (1) according to any one of claims 1 to 4, also comprising a unit? control comprising input and/or output (I/O) means which are in communication with the rotational joints (q1-q4), and control and/or processing means configured to ? acquire, by means of the input means, first position data which define for each rotational joint (q1-q4), an angular position in which said joint is located, ? determining second position data on the basis of said first position data and therapy data which define a trajectory that an upper limb of the person (P) must perform and/or a level of assistance that the device 1 must provide to said person (P ), where said second position data define for each rotational joint (q1-q4), an angular position subsequent to the position in which said joint is located, and ? transmitting, by means of the output means, the second position data to the rotational joints (q1-q4). 6. Device (1) according to claim 5, wherein the control and/or processing means are configured for ? acquire, by means of the input means, movement data which define for each rotational joint (q1-q4), a state of movement of said joint (q1-q4), ? generating the second position data also on the basis of said movement data. 7. Device (1) according to claims 5 or 6, wherein the processing and/or control means are also configured to generate the second position data relating to the second rotational joint (q2) on the basis of the second position data relating to the fourth rotational joint (q4). 8. Device (1) according to any one of claims 5 to 7, wherein the processing and/or control means are configured to generate the second position data relating to the first rotational joint (q1) on the basis of the second position data related to the third rotational joint (q3). 9. Method for controlling a device according to any one of claims 1 to 8 which comprises a plurality of of rotational joints (q1-q4), comprising ? a reading phase, in which, by means of input means, first position data are acquired which define for each rotational joint (q1-q4), an angular position in which said joint (q1-q4) is located, ? a generation step, in which second position data are determined, by means of control and/or processing means, on the basis of said first position data and therapy data which define a trajectory that an upper limb of a person (P) must perform and/or a level of assistance that the device 1 must provide to said person, where said second position data define for each rotational joint (q1-q4), an angular position subsequent to the position in which said joint (q1-q4) is found; ? a transmission step, in which the second position data is transmitted to the rotational joints q1-q4 by means of output means. The method according to claim 9, wherein ? during the reading phase, by means of the input means, also movement data are acquired which define for each rotational joint (q1-q4), a state of movement of said joint (q1-q4), and where ? during the generation step, the second position data are generated, by means of the control and/or processing means, also on the basis of said movement data. The method according to claims 9 or 10, wherein in the course of the generation step, the second position data relating to the second rotational joint (q2) are generated on the basis of the second position data relating to the fourth rotational joint (q4). The method according to any one of claims 9 to 11, wherein during the generation step, the second position data relating to the first rotational joint (q1) are generated on the basis of the second position data relating to the third rotational joint ( q3). 13. Computer product (computer program product) which can be loaded into the memory of an electronic processor and comprising a portion of software code for implementing the steps of the method according to any one of claims 9 to 12.