Patent Description:
In particular, the invention relates to an exoskeletal system comprising interchangeable modules to be applied to the hand of a user.

Haptic devices allow the user to interact with virtual environments by means of sensory feedback. In particular, we distinguish tactile haptic devices (capable of returning tactile sensations proper, such as texture, roughness, vibrations, temperature, etc.) and kinesthetic haptic devices (capable of returning sensations of strength and torque, or information relating to shape, size, weight, compliance of the material, etc.).

Kinesthetic haptic exoskeletal devices are frequently used in the field of augmented reality or teleoperation, or as real "assistants" to clinicians and physiotherapists in applications that pursue the evaluation and/or functional recovery as a result of orthopedic and neurological trauma. These provide for a simultaneous control of the position and force/torque, so as to exercise different reactions towards the user depending on the forces that the user exerts and depending on the position in which he is. This process is virtually identical to that practiced by the physiotherapist and is based on the same ability to perceive the patient's ability and strength, supporting him, guiding him, exerting appropriate forces and opposing appropriate resistances where necessary with continuous adaptations. Furthermore, the device has a variable virtual weight until it is transparent, that is until it moves under the action of the patient without the patient perceiving the weight to be moved. Finally, it can act as a force multiplier, where necessary, or initiate, and possibly complete, the movement if the patient is not able.

This haptic operating principle is known in rehabilitation robotics with the name of "assistance as needed".

Some examples of such devices are reported in <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>.

However, all the cited documents provide for a fixed connection of the actuation unit with the exoskeleton acting on the fingers: this makes it more complicated to put on (and remove) the exoskeleton, making it particularly difficult to use for users with spasticity or high flaccidity such as neurological ones, or for users with limited range of motion such as orthopedic ones.

In addition, this fixed connection prevents you from rapidly changing the size of the exoskeleton, depending on the user's anthropometric measurements, without having to replace the actuation unit as well or perform complicated steps to reconnect the actuation to the final mechanism.

<CIT> discloses an augmented reality tactile simulation system comprising a haptic glove actuation mechanism that uses cables for force transmission. In particular, an electromagnetic clutch is interposed between the system to be implemented and the actuation unit which allows the disconnection of the cable from the actuation unit, in the event that the voltage on the cable exceeds a predetermined threshold. However, <CIT> does not provide a quick coupling mechanism between actuation and glove, but only a safety system.

Document <CIT> describes a hand rehabilitation device comprising a quick coupling and release system of the flexible rods that guide the fingers of the hand with respect to the actuation unit that controls them, so as to be able to change the exoskeletal glove by adapting the system to various anthropometric measures. However, this system, comprising a soft type exoskeleton, is limited to the transmission of linear forces and does not allow the transmission of a torque.

It is therefore an object of the present invention to provide a modular exoskeletal system for handling at least one hand finger of a user which allows the quick coupling and release of the actuation unit to the exoskeleton acting on the fingers, in order to facilitate the wearing the exoskeleton and being able to quickly replace it according to the anthropometric measurements of the user's hand.

It is also an object of the present invention to provide such a device which provides abduction and adduction movements of the fingers.

These and other objects are achieved by a modular exoskeletal system for handling at least one hand finger of a user according to claims <NUM> to <NUM>.

Further characteristic and/or advantages of the present invention are more bright with the following description of an embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:.

With reference to <FIG>, a modular hand exoskeletal system <NUM> for handling at least one hand finger of a user, according to the present invention, comprises an actuation unit <NUM> and at least one finger exoskeleton <NUM>. The system <NUM> may also comprise a support plate <NUM> arranged to fasten one or more finger exoskeletons <NUM> to the user's hand.

In particular, with reference even at <FIG>, the finger exoskeleton comprises a number m ≥ <NUM> of link <NUM> arranged to rotate about a number n ≥ <NUM> of respective rotational joints <NUM> for transmitting at least one actuation torque M from a fastening link <NUM>' to the hand finger <NUM>.

Furthermore, the actuation unit <NUM> comprises an actuator <NUM> adapted to generate the actuation torque M to be transmitted to the fastening link <NUM>' through one or two Bowden cables <NUM>. In particular, each Bowden cable <NUM> comprises, as well known, an inner cable 112a and an outer coating 112b. With reference even at <FIG>, the actuation unit also comprises a locking device <NUM> that, by means of the two apertures <NUM>' obtained by the union of two portions 113a and 113b, allows to lock the end of the outer coatings 112b and to instead make the inner cable 112a to slide.

The modular hand exoskeletal system <NUM> then comprises quick coupling means arranged to cause the modular exoskeletal system <NUM> to pass between an actuated configuration, wherein the actuation unit <NUM> is connected to the finger exoskeleton <NUM> for transmitting the actuation torque M to the fastening link <NUM>', and a not actuated configuration, wherein the actuation unit <NUM> is disconnected by the finger exoskeleton <NUM>.

In particular, the quick coupling means comprises a transmission element <NUM>, steadily connected to at least one inner cable 112a, and arranged to reversibly connect to the fastening link <NUM>' generating an interlocking constraint.

This way, when the modular hand exoskeletal system <NUM> is in the actuated configuration, the transmission element <NUM> is connected to the fastening link <NUM>' and the interlocking constraint allows the transmission of the actuation torque M rotating the fastening link <NUM>' about its rotation axis x.

In particular, in the embodiment of <FIG>, the transmission element <NUM> is a pulley that is adapted, in the actuated configuration, to be rotated by the inner cables 112a to rotate the fastening link <NUM>' about a rotation axis x.

The present invention therefore allows both to facilitate the wearing of the exoskeleton <NUM>, and to be able to quickly replace it according to the anthropometric measurements of the user's hand.

Furthermore, owing to the locking device <NUM>, the invention makes it possible to maintain the pre-set tension on the cable unchanged and to avoid the need for a new adjustment of the tension of the cable at each disconnection and reconnection of the exoskeleton <NUM>.

With reference even at <FIG> and <FIG>, in a first embodiment of the quick coupling means, the pulley <NUM>, to which the Bowden cables <NUM> are connected, comprises a plurality of elongated elements <NUM>, in particular pins. Such pulley <NUM> is connected by means of magnetic force to the fastening rotational joint <NUM>', allowing the transmission of the actuation torque M to the fastening link <NUM>' thanks to the pins <NUM> which are inserted into the holes <NUM>' generating the interlocking constraint.

<FIG>, <FIG>, <FIG> show three embodiments of the quick coupling means, alternative with respect to that of <FIG>, both in the actuated configuration and in the not actuated configuration.

In particular, in <FIG>, <FIG>, two embodiments are shown in which the transmission element <NUM> is a pulley comprising two portions 130a and 130b arranged to connect to lock the ends 112a of the inner cables 112a to the pulley <NUM>. In both the embodiments, as in the solution of <FIG>, elongated elements <NUM> are provided, such as pins or screws, arranged, in the actuated configuration, to be inserted into the holes <NUM>', generating the interlocking constraint, for transmitting the actuation torque M to the fastening link <NUM>'.

In the embodiment of <FIG>, the transmission element <NUM> is a shaped element comprising two portions 130a and 130b, arranged to connect to lock the ends 112a of the inner cables 112a. In this embodiment, the fastening link <NUM>' comprises a receiving element 130c having complementary geometry with respect to the transmission element <NUM>. In particular, the portion 130a comprises a tooth 131a that is adapted, in the actuated configuration, to be inserted into the hole 126a', generating the interlocking constraint, for transmitting the actuation torque M to the fastening link <NUM>'.

In general, in all the embodiments described, the transmission element <NUM>, in the actuated configuration, can be constrained to the fastening link <NUM>'by means of magnets <NUM> arranged to produce a magnetic force acting in a direction parallel to the rotation axis x.

In the <FIG>, <FIG>, two possible embodiments of the quick coupling means are shown that allow the easy connection of the locking device <NUM> to an engagement portion <NUM> of the finger exoskeleton <NUM>. In particular, in an embodiment of <FIG> a "snap fit" system is provided, while in <FIG> pins <NUM> are provided connected to the locking device <NUM> and arranged to fit into the grooves <NUM>'.

In both embodiments, the engagement portion <NUM> defines an engagement axis y at which the locking device <NUM> is adapted to engage. Such engagement axis y is arranged at a determined distance D by the rotation axis x, in order to allow, at the moment of quick coupling, to provide a tension to the inner cables 112a such as to allow a prompt transmission of the actuation torque M to the pulley <NUM>.

This way, it is sufficient to adjust only once the tension required to the cables Bowden <NUM>, by adjustment means located near the actuator <NUM>. Then, the distance D will guarantee, at each passage between not actuated configuration and actuated configuration, that the Bowden cables <NUM> are subjected to the correct tension for transmitting the motion. Furthermore, in an embodiment not shown in the figure, adjustment means can also be provided arranged to translate the engagement axis y for adjusting the distance D.

Such aspect allows the present invention to pass between the not actuated configuration and the actuated configuration much faster than the prior art, since, in addition to having an easy connection system between actuation unit <NUM> and exoskeleton <NUM>, it also allows to avoid the adjustment of the tension of the cable at each coupling.

In the <FIG> an embodiment is shown of the quick coupling means wherein the locking device <NUM> is integral to the pulley <NUM> by means of a bridge <NUM>, so as to maintain the distance D constant also in the not actuated configuration and to further facilitate the connection of the exoskeleton <NUM>, maintaining the adjustment of the cable.

In the <FIG> an embodiment of the quick coupling means is shown wherein a cam mechanism <NUM> is provided to facilitate the assembly and the disassembly of the exoskeleton <NUM>. In particular, the cam mechanism <NUM> passes between a release configuration (<FIG>), in which the cables 112a are loosened, and an operating configuration (<FIG>), in which the cables have the optimal tension to actuate the exoskeleton <NUM>.

This way, when the exoskeleton <NUM> must be released, it is possible to set the cam mechanism <NUM> in the release configuration, allowing the exoskeleton <NUM> to be disconnected with less force, as the friction due to the interlocking constraint between the pulley <NUM> and the fastening link <NUM>' is less. Still in the release configuration, the exoskeleton <NUM> can be re-engaged without effort. Once the exoskeleton <NUM> has been brought into position, the cam mechanism <NUM> can be returned to the operating configuration, restoring the adjusted tension in the cable and allowing an optimal actuation.

In <FIG>, an embodiment of the invention is shown wherein a support plate <NUM> is also provided arranged to be integrally constrained to the hand of the user and to allow a removable connection with the finger exoskeleton <NUM>. In particular, the finger exoskeleton <NUM> is rotoidally connected by inserting the pin <NUM> in one of the holes <NUM> by means of magnets <NUM>. This way, the exoskeleton <NUM> can rotate about its axis z following the adduction and abduction movements of the finger. Furthermore, to ensure grip between exoskeleton <NUM> and support plate <NUM>, without preventing the rotation about its axis z, the plate comprises an iron-magnetic plate <NUM> arranged to attract the magnets <NUM> integral with the exoskeleton <NUM>.

<FIG> shows an embodiment of the modular exoskeletal system <NUM> (the actuation unit is not shown for simplicity) wherein the support plate <NUM> is connected to the palm of the user's hand and two finger exoskeletons <NUM> are connected to it. A third finger exoskeleton <NUM> for thumb is also provided having its own support plate <NUM>' independent from the other fingers. This allows adjusting the plane of opposition of the thumb with respect to the other fingers.

Claim 1:
A modular exoskeletal system (<NUM>) for handling at least one hand finger (<NUM>) of a user, said modular exoskeletal system (<NUM>) comprising:
- at least one finger exoskeleton (<NUM>) comprising n ≥ <NUM> rotational joints (<NUM>) and m ≥ <NUM> link (<NUM>) arranged to rotate by means of respective rotational joints (<NUM>), said n ≥ <NUM> rotational joints (<NUM>) comprising a fastening rotational joint (<NUM>') arranged to allow the rotation of a fastening link (<NUM>') about a rotation axis x, said or each finger exoskeleton (<NUM>) arranged to transmit an actuation torque M from said fastening link (<NUM>') to said hand finger (<NUM>);
- an actuation unit (<NUM>) comprising:
- an actuator (<NUM>) adapted to generate said actuation torque M;
- at least one Bowden cable (<NUM>) comprising an inner cable (112a) and an outer coating (112b), said or each Bowden cable (<NUM>) arranged to transmit said actuation torque M to said or each finger exoskeleton (<NUM>);
- a locking device (<NUM>) having at least one opening (<NUM>') arranged to constrain said outer coating (112b) of said Bowden cable (<NUM>) and to allow said inner cable (112a) to slide;
- quick coupling means arranged for causing said modular exoskeletal system (<NUM>) to reversibly pass between an actuated configuration, wherein said actuation unit (<NUM>) is connected to said or each finger exoskeleton (<NUM>), and a not actuated configuration, wherein said actuation unit (<NUM>) is disconnected by said or each finger exoskeleton (<NUM>);
wherein said quick coupling means comprises a transmission element (<NUM>) steadily connected to said or each inner cable (112a), said transmission element (<NUM>) arranged to connect to said fastening link (<NUM>') in a reversible manner by means of an interlocking constraint;
and wherein, in said actuated configuration, said transmission element (<NUM>) is connected to said fastening link (<NUM>') and said interlocking constraint is arranged to transmit said actuation torque M from said actuation unit (<NUM>) to said fastening link (<NUM>') rotating said fastening link (<NUM>') about said rotation axis x.