Patent Application
20210145687
The present invention relates to the field of motor assistance and rehabilitation of anatomical parts.
In particular, the invention relates to a kinematic chain for assisting a spherical motion of an anatomic joint of a finger of the hand.
The exoskeletons proposed in the literature are generally designed according to two main approaches, sometimes in part interconnected.
A first category, widely used for example in the case of exoskeletons for the hand, is that of the so-called “soft” exoskeletons, devices consisting of flexible elements (eg gloves) that can be easily worn, in which some elements also “soft” are used as anchorage of the glove to the various segments of the hand (or other organ) and connected to the actuation system (usually with cables or based on pneumatic actuators). These devices are particularly suitable when the forces involved are not high and when you do not want to accurately measure the patient's performance in the execution of the motion (for example in terms of applied force or articular kinematics).
The second category consists of “rigid” exoskeleton, i.e. robotic devices consisting of a series of active and/or passive joints and links that are engaged to the person by means of specially designed shells (rigid or semi-rigid). This type of architecture allows to apply high forces or torques (in the order of magnitude appropriate for the treatment of spasticity, for example) and to quantify the performance of the patient in a precise and repeatable manner without generating unwanted forces on the anatomical joint. In this case, the robot must at the same time allow the patient to perform the motion autonomously when possible (resulting yielding and not rigid at the interface with the patient's hand), or apply the necessary forces/couples to complete the motion when the person fails to do so (in this case then resulting in a rigid interface).
As regards, in particular, the anatomical joints that perform spherical motions, such as the articulation of the thumb or shoulder, the technological challenge is to develop structures able to simultaneously reproduce the joint motion without generating parasitic reactions, adapt to different anthropometric sizes, have a small footprint and also achieve a rigid or yielding man-robot interaction depending on the need for rehabilitation treatment.
In U.S. Pat. No. 7,862,524 an exoskeletal rehabilitative apparatus is presented that is able to assist the rotation motion of the shoulder, using three rotational joints having orthogonal axes to each other and accidents at the scapulohumeral joint. Some passive joints are then provided to adapt the exoskeleton to different anthropometric measurements of the arm and shoulder. The interaction of forces between the exoskeleton and the user occurs at the elbow and at the hand grip.
The intersection of the axes of the rotational joints at the shoulder joint allows, theoretically, to reproduce the spherical motion, without producing parasitic reactions.
However, in practice, the alignment between the point of intersection between the rotation axes of the joints and the center of rotation of the anatomic articulation is not absolutely trivial to be obtained without the presence of adequate regulation systems. This problem is further amplified if one wishes to use the same kinematic principle to assist the spherical motion of the articulation of the thumb of a hand. The document U.S. Pat. No. 7,862,524 provides the possibility of adapting passively to different lengths of the arm and the forearm, but does not in any way deal with the problem of alignment between the two centers of rotation mentioned above, being in fact not very effective in the practical application of the theoretical principle.
It is therefore a feature of the present invention to provide a kinematical chain for assisting a spherical motion of an anatomical joint of a finger of the hand of a user for which allows to reproduce this spherical motion without generating parasitic forces.
It is also a feature of the present invention to provide such a kinematical chain that is adaptable to different anthropometric measurements of a user.
It is also a feature of the present invention to provide such a kinematical chain which allows to easily and effectively align the center of rotation of the kinematic chain with that of the anatomic joint.
It is still a feature of the present invention to provide an hand exoskeleton which implements this kinematic chain to assist the spherical motion of a carpo-metacarpal joint of the thumb.
These and other objects are achieved by a kinematical chain for assisting a spherical motion of an anatomical joint of a finger of the hand of a user, said anatomical joint having centre of rotation P and being arranged for allowing a relative motion of a finger of the hand with respect to a portion of hand of the user, said finger of the hand defining a longitudinal direction δ, said kinematical chain comprising:
Advantageously, an adjustment means is provided arranged to adjust the direction of the rotation axes x, y and z for bringing the centre of rotation O substantially at the centre of rotation P, in such a way that the kinematical chain carries out the spherical relative motion between the longitudinal direction δ and the portion of hand (220) about the anatomical joint without generating parasitic forces on the user.
In particular, the adjustment means comprises at least two threaded fasteners arranged to adjust its own height for adjusting the relative position between the centre of rotation O and the centre of rotation P of the anatomical joint.
Alternatively, the adjustment means comprises a plate comprising a first flat portion and a second flat portion orthogonal to each other, said first flat portion comprising a first couple of circular slots arranged to allow a rotation of the third rotational joint with respect to the portion of hand about an axis orthogonal to the first flat portion, said second flat portion comprising a second couple of circular slots arranged to allow a rotation of the third rotational joint with respect to the portion of hand about an axis orthogonal to the second flat portion.
According to another aspect of the invention, an hand exoskeleton is claimed for assistance to a spherical motion of a carpo-metacarpal joint of the thumb of a user, said hand exoskeleton comprising:
Advantageously, the hand exoskeleton comprises furthermore:
In particular, an exoskeleton for fingers is also comprised arranged to assist a flexion/extension motion of a middle finger, a ring finger and a little finger of the user.
Advantageously, an orthotic shell is also comprised arranged to engage the hand exoskeleton to the hand of the user, said orthotic shell comprising:
In particular, the thumb exoskeleton and the index exoskeleton are integral to the phalanxes, respectively, of the thumb and of the index by means of rings wearable on the fingers and having at least one pin and a magnet arranged to engage with the exoskeletons. The magnet ensures the contact between the ring and the exoskeleton, whereas the pin allows to fasten the position of contact. In order to avoid the relative rotation between the ring and the exoskeleton also can be provided a second pin or a slide.
According to a further aspect of the invention, an orthotic shell is claimed arranged to engage with the hand exoskeleton to the hand of a user, said orthotic shell comprising:
Further characteristic and/or advantages of the present invention are more bright with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:
In the
The anatomical joint 200 allows a spherical rotation of the finger of the hand 210 with respect to a portion of hand 220 about its own centre of rotation P.
The kinematical chain 100 comprises a first rotational joint 110 engaged to the finger of the hand 210 and to a first connection link 115. The first rotational joint 110 is arranged to provide a relative rotation α between the first connection link 115 and the finger of the hand 210 about a rotation axis x coincident with the longitudinal direction δ defined by the finger of the hand 210 itself. In particular, the rotational joint 110 comprises an inner ring, integral to the finger of the hand 210, and an outer ring, integral to the connection link 115, and arranged to rotate with respect to the inner ring.
The kinematical chain 100 comprises then a second rotational joint 120, engaged to the first connection link 115 and to a second connection link 125, and arranged to provide a relative rotation β between the two links about a rotation axis y.
The kinematical chain 100 comprises then a third rotational joint 130, engaged to the portion of hand 220 and to the second connection link 125, and arranged to provide among them a relative rotation γ about a rotation axis z integral to the portion of hand 220.
In particular, the rotation axes x, y and z intersect in a centre of rotation O coincident with the centre of rotation P of the anatomical joint 200.
This way, the kinematical chain provides a spherical rotation of the rotation axis x with respect to the portion of hand 220, allowing to follow the spherical rotation of the finger of the hand 210 and to assist it, if the joints are active, without generating unwanted forces neither on the finger of the hand 210 itself, nor on the portion of hand 220, nor on the articulation.
In
With reference to
In particular, the adjustment means 150 comprises four threaded fasteners 155 arranged to adjust its own height for adjusting the relative position between the intersection of the axes rotation x, y and z, i.e. the centre of rotation O, and the centre of rotating the anatomical joint P.
In
In particular, the first rotational joint 110 engages with the thumb by the orthotic shell 110′.
In particular, the adjustment means 150 comprises a plate 156 located between the third rotational joint 130 and a frame 320 arranged to be integral to the portion of hand 220, i.e. With the carpal portion of the hand of the user. Such plate 156 comprises two flat portions located at 90° to each other, on which are provided, respectively, a first couple of circular slots 156′ and a second couple of circular slots 156″. The elongated holes 156′ and 156″ allow the third rotational joint 130 of the kinematical chain 100 of having a degree of freedom, respectively, in the angle of “yaw” and of “pitch” with respect to the orthotic shell fastening to the palm of the hand.
Furthermore, the kinematical chain may comprise a variation means for adjusting the length of the connection link 115 and 125 and conform the kinematical chain to different measuring the hand (not shown in figure for the sake of clearness of drawing). For example, the link 115 and 125 can be telescopic or connected to the adjacent rotational joints by means of elongated holes that allow a relative translation.
In the
In particular, the exoskeleton 300 comprises, in addition to the kinematical chain 100, a frame 320 integral to the back of the hand of the user, in order to allow an engagement the third rotational joint 130 to the back of the hand.
The exoskeleton 300 also comprises a thumb exoskeleton 310, which is adapted to assist the motion of flexion/extension of the thumb of the user, and an index exoskeleton 330 integral to the frame 320 and arranged to assist the motion of flexion/extension of the index of the user. In particular, the first rotational joint 110 engages with the thumb exoskeleton 310.
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The foregoing description some exemplary specific embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, accordingly, it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. it is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102017000079086 | Jul 2017 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2018/055085 | 7/10/2018 | WO | 00 |
