DESCRIPTION

Field of the invention

The present invention relates to the field of wearable robotics for movement enhancement and/or assistance.

In particular, the invention relates to a system for managing the actuation and the simultaneous under-actuation of prosthetic and/or orthotic joints.

Description of the prior art

In the field of wearable robotics the need to have robots that have the lowest possible weight/power ratio is increasingly sought after.

In general, the power of the device is decided a priori when defining the functional specifications. For example, the overall power that an active knee and ankle prosthesis must have is different if the device is to assist the user in walking, running or climbing up and down stairs.

Therefore, given the power required on the various joints, the challenge is to reduce the weight of the robotic device capable of expressing this power. To accomplish this optimization, in addition to reducing the weight of the materials, the only possibility is to reduce the components that are conceptually necessary to have the required functionality, such as actuators, for example.

There are, in the prior art, numerous systems which seek to have a number of actuators lower than the number of joints to be moved in order to reduce the weight of the overall system. However, these systems are often very complex and not very versatile, above all because they are not able to manage different powers on the joints operated by the same actuator, failing to comply with the required specifications.

US2016310344 describes a system for assisting the walk of a user comprising a pair of femoral supports and a unit for the motion transmission. In particular, the transmission unit comprises a differential adapted to move in phase the two femoral supports, appropriately distributing the power supplied.

However, US2016310344 does not provide the possibility of switching between various actuation modes, allowing to decide whether to actuate a single joint or a plurality of joints or if to change the transmission ratio on the same joint.

Therefore, in the case, for example, of assistance to the knee and ankle joints during a walk, in which the knee joint and the ankle joint must be operated in sequence, using the device described in US2016310344 it would be necessary using a plurality of actuators dedicated to the individual joints, with obvious disadvantages in terms of weight, reliability and cost-effectiveness of the exoskeleton.

Summary of the invention

It is therefore a feature of the present invention to provide a system for handling robotic joints arranged to assist the movement of a user which allows having a number of actuators lower than the number of joints to be moved.

It is also a feature of the present invention to provide such a system which allows the power dedicated to each joint to be managed independently, even though it does not have a joint dedicated thereto.

It is another feature of the present invention to provide such a system that allows to vary the work configuration quickly and dynamically, depending on the need imposed by the motion of the user instant by instant.

It is still a feature of the present invention to provide such a system which allows to manage an indefinite number of joints to which different powers must be applied.

These and other objects are achieved by a system for handling robotic joints arranged to assist the movement of a user according to claims from 1 to 17.

The main advantage of the present invention lies in the possibility of selecting the various connection configurations between actuators and robotic joints in real time during the movement of the user. In particular, it is possible to use the same actuator to move different joints, depending on the phase of motion of a user. Furthermore, the same actuator can be used to implement several joints simultaneously, thanks to the under-actuation mechanism. It is therefore possible to have a much lower number of actuators than the joints to be moved, with a clear saving in terms of weight and bulk compared to the prior art.

Moreover, a plurality of output paths can be used to actuate the same joint, substantially allowing to change the transmission ratio, i.e. the joint movement.

A further advantage can be provided by using a control unit that allows the system to be fully automated, by means of sensors that provide the control unit with information on a user's position, motion and intentions, so that they can be selected in intelligent way the optimal configurations of transmission of the motion.

Brief description of the drawings

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:

— Fig. 1 shows a graphical representation of the principle of operation of the system according to the present invention;

Fig. 2 shows, in a schematic manner and by way of example, a possible exemplary embodiment of the system for handling robotic joints, according to the present invention, wherein two actuation units are provided for handling five robotic joints arranged throughout the body of the user;

— Fig. 3 shows, in a schematic manner and by way of example, another possible exemplary embodiment of the system, wherein two actuation units are provided for handling three robotic joints arranged at the hip, knee and ankle of a user;

— Fig. 4 shows an example of implementing the system on a knee exoskeleton;

— Figs. 5A and 5B show, in front and rear view, an example of implementing the system on an exoskeleton for knee and ankle;

— Figs. 6A and 6B show some possible exemplary embodiments of the connection means that allow to pass between the various transmission configurations .

Description of a preferred exemplary embodiment

In Fig. 1 shows an exemplary diagram of the operating principle of the system 1 for handling robotic joints, according to the present invention.

The system comprises a number p of robotic joints (with k = l,2,...,p) and a number n of actuation units G _j (with i = 1,2, ...,h) . Each actuation unit G _j comprises in turn an inlet / _j , arranged to provide an inlet power Qi, and a number of outlets Oi _j (with j = 1,2, ...,hi _t) .

In particular, in the example of Fig. 1 there is p = 8 and n = 8. In the following table are numerically given the purely exemplifying data shown in Fig. 1.

Taking, for example, the actuation unit G _lr we see that it comprises the inlet way / _c and m ₁ = 8 outlets 0 _1j , i.e. the outlets 0 _llf 0 ₁₂ , 0i ₃ , 0i ₄ , 0i ₅ , 0 _16/ 0 _17/ 0 ₁₈ · Furthermore, the actuation unit G ₁ is arranged in the configuration C ₁₅ (highlighted by the number of filled boxes), where the inlet way / _j is simultaneously connected to to h = 5 outlets 0 _1j , selected among the 8 above cited. And the like for actuation units G _{2 ~} G ₈ .

Each of the outlets Og connected to the respective inlet Ii can transfer an outlet power 7y to at least one or more the 8 robotic joints .

In Fig. 2 there is an example of application of the system 1, wherein two actuation units G ₁ and G ₂ are provided arranged to actuate 5 robotic joints: ?i at the shoulder, R ₂ at the elbow, R ₃ at the wrist, R ₄ at the knee, R ₅ at the ankle . In particular, the first actuation unit G ₁ comprises one inlet / _x and two outlets O _l and 0 ₁₂ , whereas the second actuation unit G ₂ comprises one inlet / ₂ and two outlets 0 ₂₁ and 0 ₂₂ .

The outlet O _l allows the first actuation unit G ₁ to actuate the joints R _lr R ₂ and R ₃ by means of a first motion transmission chain M _ll whereas the outlet 0 ₁₂ allows the first actuation unit G ₁ to actuate the joints R ₄ and R ₅ by means of a second motion transmission chain M ₁₂ . The second actuation unit G ₂ instead can actuate the joints R ₄ and R ₅ by means of a third motion transmission chain M ₂₁ and the joint R ₅ by means of a fourth motion transmission chain M ₂₂ .

This allows the joints R ₄ and R ₅ to have multiple actuation channels, coming from different outlets with different powers, ensuring to dynamically adapt to different handling needs, for example during the various phases of a walk or even in the passage between a walk and a race. In fact, the system can simply switch between the various configurations, which connect and disconnect the inlets and outlets of the various actuation units, to modify the power supplied on the single joint. For example, it is possible to provide a very high torque to the ankle during the foot support phase, and subsequently to reduce the torque and increase the speed of execution, when the ankle is in the phase of detaching the foot from the ground. Similarly, and at the same time, a transition between different configurations of motion can be made for the knee and the hip .

Fig. 3 shows an exemplary embodiment, which is also exemplary, of the system 1, wherein there are two actuation units both applied to 3 robotic joints of the leg.

Fig. 4 shows an example of implementing the system 1 on a knee exoskeleton. In this case the two outlets O _l and 0 _\2 both actuate the same robotic joint R _lr precisely the knee one, providing the possibility of having an actuation with two different transmission ratios, similarly to a car gear.

Figs . 5A and 5B show, in front and rear view, an example of implementing the system on a prosthesis for knee and ankle. In this case, there are two robotic joints and R ₂ and a single actuation unit G ₁ arranged to pass between various configurations .

In particular, there is a first configuration where the inlet / _x is connected to the first outlet 0 _l and wherein Qi ⁼ Ti _l · In this configuration, depending on the setting of the motion transmission chains, the following power distributions can be obtained:

— T _lt applied to the first joint R^;

— T _l applied to the first joint R and to the second joint R ₂ ; Alternatively, there is a second configuration C ₁₂ where the inlet / _x is connected both to the first outlet O _l and to the second outlet 0 ₁₂ and — T _lt + T ₁₂ . In this configuration, depending on the setting of the motion transmission chains, the following power distributions can be obtained:

T _lt applied to the first joint R _lr T ₁₂ applied to the first joint R _1;

— T _lt applied to the first joint R _lr T ₁₂ applied to the second joint R _2;

— T _l applied both to the first joint R and to the second joint R _2r T ₁₂ applied to the second joint

Rz ;

T _l applied both to the first joint R and to the second joint R ₂ , T ₁₂ applied both to the first joint R ₁ and to the second joint R _2;

Figs. 6A and 6B show some possible exemplary embodiments of the connection means 120 that allow to pass between the various transmission configurations.

In particular, in Fig. 6A the inlet / _j comprises a transmission element 105 and the outlets O _l and 0 ₁₂ comprise the receiving elements 110 and 110' . Connection means 120 is also provided arranged to pass between a disengagement configuration and an engagement configuration of. In particular, two rotating elements 125 and 125' are provided, both of "C" type, arranged to rotate about respective axes x' and x". The rotating elements 125 and 125' have two ends with a profile having the shape of a logarithmic spiral.

Thanks to this particular geometry in the form of a logarithmic spiral, in the engagement configuration the rotating element 125 binds by friction on the wall of the receiving elements 110 and 110', allowing to transfer both the power inlet Q both the angular speed w from the inlet to the outlet. With respect to other geometries, the logarithmic spiral geometry allows a transmission most effective of the angular moment, since the force of friction given by the binding increases with the rotation: this causes the generation of a totally stable connection between the transmission element 105 and the many receiving elements until the rotating element 125 is not rotated about its rotation axis x' to pass to the disengagement configuration.

In particular, each rotating element "C" type can be arranged in the three positions shown in the figure with a continuous line and a dotted line:

- in contact with a receiving element with the logarithmic spiral profile in a first direction;

- in contact with a receiving element with the logarithmic spiral profile in the opposite direction;

not in contact with a receiving element. Therefore, suitably positioning the rotating elements 125 and 125' , it is possible to connect the inlet alternatively to the first outlet, to the second outlet, to both the outlets or to none, both in a direction of rotation and in the another one.

In Fig. 6A a similar exemplary embodiment is shown having 4 outlets 0 _llr 0 ₁₂ , 0 ₁₃ and 0 ₁₄ with relative receiving elements 110a, 110b, llOa' , 110b' . There are also 4 rotating elements 125a, 125b, 125a' , 125b' , which, in addition to rotate about the respective axes x' and x", can also translate along of them, allowing pass more quickly between the engagement configuration and the disengagement configuration.

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 .