IT201800009210A1 - ACTIVE WEARABLE ROBOT WITH BACK JOINT - Google Patents

Description

ACTIVE WEARABLE ROBOT WITH BACK JOINT

DESCRIPTION

The present invention relates to an under-implemented wearable active robot where one of the outputs is associated with an articulated mechanism adapted to correspond with the vertebral column of a user.

The term active wearable robot in the present description will generally indicate any prosthetic or exoskeletal device implemented mechanically and intended to be worn by a user as an aid to motion or to replace a limb and / or body portion.

As known, the constructive complexity of these robots tends to make them bulky and heavy; therefore, with known robots difficulties arise in practical use, especially for some subjects (for example elderly people or subjects with a frail physique), who may even be unable to wear the robot. In any case, robots of this kind tend to be uncomfortable or burdensome for all other subjects to wear.

The technology is therefore moving with a view to trying to reduce the size and weight of wearable robots. The reduction of weights and dimensions in the exoskeletal robots would not only allow a more comfortable usability by the user but also a greater tolerability of the robot itself. In fact, very heavy or even bulky robots are badly accepted by the user, either because of the difficulty of use, or because of the strong aesthetic and emotional impact they cause in use.

However, no satisfactory technical solutions have been found to date to achieve this goal: in fact, constructive simplicity is not easy to obtain because the functions required by these aid systems are often complex and multiple. Furthermore, it must be taken into account that an obtained constructive simplicity must not represent a deterioration in the reliability and functionality of the system.

The aim of the present invention is therefore to solve the above-mentioned problems of weight and structural complexity with the same functionality and reliability of the current robots.

In particular, the object of the present invention is to provide a wearable active robot which allows a simplification of the mechanical power transmission chain of the robot while at the same time maintaining a high functional reliability.

It is still an object of the present invention that the robot according to the invention allows an overall weight reduction.

These and other objects are achieved by a wearable active robot according to the first of the appended claims. Further features of the invention are the subject of the dependent claims.

Characteristics and advantages of the system according to the present invention will become clearer from the following description of an embodiment thereof, given by way of non-limiting example, with reference to the attached figures in which:

- Figure 1 schematically represents and in conceptual blocks an under-implementation group applied to the robot according to the invention;

Figure 2 is again a schematic block representation of a wearable robot that installs the under-implementation assembly of Figure 1;

- Figure 3 schematically shows a block representation of a specific embodiment of the invention in which the underactivation group comprises torque sensor means;

- Figures 4a and 4b show from two different angles a specific embodiment of a wearable robot with an under-actuation unit connected to three articulating modules which specifically are two hip modules and a back module;

Figure 4c shows in detail an articulated module suitable for interfacing with the back of a user;

figure 5 shows a detail of the under-actuation group of the robot of figures 4a and 4b;

- figure 6 shows an embodiment of a SEA-type architecture;

- Figures 7a and 7b conceptually illustrate two possible embodiments of the under-implementation unit of the preceding figures.

With reference to the aforementioned figures and in particular for the moment to Figures 1 and 2, an underactivation assembly indicated globally with the reference number 1 is described, intended to be installed on an active wearable robot, globally indicated with the reference number 2.

The term active wearable robot generically indicates any mechanically implemented prosthetic or exoskeletal device intended to be worn by a user as an aid or as a replacement for a limb and / or body portion.

Returning to the invention, the under-actuation unit 1 comprises actuation means 10 which generate a torque at a primary motion output 100 to move at least two articulated modules 20, 21 of the robot intended to correspond, in use, with respective single body joints. or polyarticular of the user.

The actuation means comprise one or more actuators controlled by an energy source controlled by an electronic controller (not shown). The term actuator can be understood to mean linear type actuators but also, for example and not limited to electric motors, electroactive polymers, hydraulic power systems such as for example a hydraulic pump.

The term exoskeletal articulated module then means any feasible joint of the robot which has at least one degree of freedom, such as for example joints of the knee, ankle, elbow, wrist. In any case, polyarticulated structures that include kinematic chains are also included in this definition; structures of this kind are suitable to be associated in particular with the back and in particular with the spinal joint of the user and in this case they follow and reproduce the movements of the vertebral column or the pelvis of the user and in this case reproduce the movement of the pelvis joint -hip. An example of a polyarticulate structure suitable for application in association with the pelvis-hip joint is described in patent application WO2017216663 of the same applicant incorporated herein by reference.

An example of a polyarticulate structure specifically suitable for association with the user's spine will instead be made later in the description.

As mentioned above, the actuation means 10 define the primary motion output 100 to which a first motion distribution element 11 is connected. The first motion distribution element 11 therefore receives at its input 100 'the torque generated at the output of the means of actuation 10.

The first motion distribution element 11 further defines two differential derivative motion outputs 110 and 111 each of which is adapted to connect with a respective articulated module 20, 21 of the robot or with a second motion distribution element 12, 12 'in its once operationally interfaced with at least two further articulated exoskeletal modules 20 ', 21', 20 '', 21 ''.

Therefore, the actuation means 10, while defining a primary motion output 100, obtain the movement of at least two articulated modules 20, 21, thanks to the interposition of the first motion distribution element 11 which receives the input motion from the actuation means and distributes it in differential mode (ie in the form of a differential) to the two derived outputs 110, 111 and therefore, consequently, to the articulated exoskeletal modules operatively connected to them.

The exoskeletal articulated modules which can be implemented with the actuation means 10 are therefore potentially infinite. For example, reference should be made to the schematic diagram of the robot of Figure 2 where to each derived motion output 110, 111 of the first motion distribution element 11 is connected respectively a further motion distribution element and specifically a second 121 and third 12 ' motion distribution element. To the differential motion outputs 120 ', 121', 120 '', 121 '' of each of these second and third distribution elements are in turn connected second and third groups of actuable modules of the robot, 20 ', 21', 20 '', 21 ''. Therefore, in this case, four articulated exoskeletal modules are implemented with the actuation means 10. If, on the other hand, fourth and fifth motion distribution elements were in turn connected to the second 12 'and third 12' 'motion distribution elements, the articulated modules that could potentially be implemented starting from only the primary motion output 100 defined by the actuation means 10 would be in even more. The under-actuation unit thus achieves the movement of complex robotic structures with a constructive simplicity never achieved by currently known robots.

According to a further aspect of the invention, the under-actuation group also comprises torque sensor means 13 interposed between the first motion distribution element 11 and the actuation means 10, therefore corresponding to the primary motion output 100.

Said sensor means can comprise, for example but not limited to, a transmissive element with elastic response for the transmission of a torsional stress associated with at least one position encoder to determine its torsional deflection and therefore the torque knowing the elastic constant of the elastic transmission element .

The architecture that includes sensor means of this type in series with actuation means is known as SEA (series elastic actuator).

Figure 6 shows an embodiment of SEA architecture. The torsional elastic transmissive element is indicated in the figure with the number 130. The actuation means in turn comprise a motor 10a and a drive shaft 10b which defines a first reduced motion output 10c. This motion output of the drive shaft 10b is interfaced with a first connection flange of the transmissive element 130a; a second flange 130b longitudinally opposite to the first is connected to a socket connection element 131 which supports on its outer periphery the primary motion output 100 of the actuation means 10. Furthermore, the sensor means comprise, in this specific embodiment, two encoder, of which a first encoder 132 mounted in such a way as to read the movement on the first flange 130a and a second encoder 133 mounted in such a way as to read the movement on the second flange 130b. The measurement difference read between the two encoders makes it possible to evaluate the torsional deflection of the elastic transmission element and therefore, knowing its elastic constant, the torque transmitted to the socket connection element and therefore on the first primary motion output 100. Possibly only one encoder can be provided, for a direct reading of the torsional deflection.

The sensor means 13 are therefore suitable for detecting the torque actually absorbed by it and the possible action that the individual joints exert in feedback on the actuation means, in case the joints are moved by the user himself. The sensor means is typically interfaced with a control unit configured to control the actuation means in feedback as a function of an external perturbation received by at least one of the two or more articulated modules. This feedback control makes it possible to make the robot "transparent" towards a possible force exerted by the user directly on the articulated module, a force which, in the absence of such a control, would be unwanted and in a substantially uncontrolled way redistributed by the distribution element motion, on the basis of the differential distribution criterion, on one or more articulated modules connected to it.

Specifically, the SEA architecture is able, by reading the deformation of the torsional elastic transmission element located downstream of the actuation means and upstream of the motion distribution element, to give the control unit the information of which is the torque that passes in that transmission section and therefore allows to close the control loop in a timely manner as regards the active delivery for the necessary motor task. This architecture also allows you to control the robot in feedback if the user wants to be able to impose motion from the outside. If there was an irreversible transmission, all the movement imposed by an output of the motion distribution element would have an equal and opposite impact on the second which obviously could not move freely. Sensor means upstream of the motion distribution element therefore allow the engine to cancel the resistant torque by canceling the algebraic difference of the motion generated by the two outputs subjected to an input force supplied from the outside, or rather by the user himself.

In a preferred embodiment of the invention the motion distribution element is a differential. The differential is of the mechanical type, that is materialized by a planetary gear.

Optionally, the differential can also be of the pneumatic / hydraulic type as shown in figures 7a and 7b. In greater detail, in this case the actuation means 10 comprise a hydraulic pump and the motion distribution element is materialized by a pipe whose fluid inlet 100 'materializes the motion input, while the derived outputs 110 and 111 represent motorcycle rides. Each motion output is connected at the input to a hydraulic motor which implements a relative joint.

Reference is now made to the embodiment illustrated in Figures 4a, 4b and 5. In this example, the actuation means 10 comprise an electric motor 10a in series with a sensorized spring at the ends 10b, to define an architecture of the SEA type such as the one previously described. The primary motion output 100 is materialized by a first meshing element. This primary motion output 100 is connected to a first differential 11 which has a second meshing element 110 'adapted to mesh with the first meshing element 100 to receive the torque delivered by said actuation means 10. Specifically, the first and second meshing element are materialized by toothed wheels, even if other equivalent solutions from the functional point of view may be provided.

The first differential 11 provides two differential motion outputs, of which a first derived output 110 and a second derived output 111. The first derived output 110 is connected to a first articulated module 20. The second output 111 is connected to a second differential 12 .

The first derivative output 110 is materialized by an meshing element such as a pulley adapted to operatively interface with a respective motion input pulley 20a to the first articulated module 20, as shown specifically in Figures 4a to 4c. In the specific case, the pulley 20a provides the input motion to an articulated kinematic mechanism adapted to be associated with the back joint, or with the vertebral column of a user.

In this specific example, the articulated kinematic system comprises an exoskeletal kinematic chain adapted to assist the movement of a polyarticular bone chain. The exoskeletal kinematic chain, thus defining a back exoskeleton, comprises a frame integrally connected to a portion of the user's pelvis and a number of exoskeletal links 20b, one of which is integral with the frame.

The chain also comprises a number of exoskeletal rotary joints 20d, each of which is such as to allow relative rotation between two exoskeletal links adjacent to it about its own axis of rotation X.

Each exoskeletal rotary joint is arranged at a certain distance from the previous 20d exoskeletal rotary joint along the back exoskeleton, each distance being constant for each value of relative rotations.

Each exoskeletal link 20b is also connected to a corresponding vertebra of the vertebral column by means of a kinematic constraint such as to allow the transmission of at least one orthogonal force component to the exoskeletal link and / or to the corresponding vertebra.

At each exoskeletal rotoidal joint 20d there is a pulley 20a 'able to rotate around a corresponding axis of rotation, and at least one inextensible cable 20c in contact by friction with each pulley 20a' and constrained to an exoskeletal link at the end of the 'exoskeleton, opposite to the frame. The relative derived motion output is adapted to pull the at least one cable 20c so as to bring the exoskeletal links to rotate around the respective exoskeletal rotoidal joints. Optionally, two or more cables may be provided alternately pulled so as to cause the exoskeletal links to rotate around their respective exoskeletal rotoidal joints in a clockwise and / or counterclockwise direction.

The second derived output 111 is materialized by an meshing element (specifically a toothed wheel, although also in this case the implementation of other functionally equivalent solutions cannot be excluded).

This second derivative output 111 is connected with the motion input 12a of the second differential 12, materialized by a complementary meshing element. The second differential provides a first 121 and a second 122 motion output. The two derived motion outputs 121 and 122 are meshed with respective motion inputs 21a and 22a of two articulated modules according to 21 and third 22 to provide rotational motion. In particular, the two motion inputs 21a, 22a are materialized by pulleys that have a degree of freedom in rotation according to their own axis perpendicular to the motion output axis of the second differential. These pulleys provide motion to an articulated kinematics that defines the two second and third articulated exoskeletal modules 21 and 22 which in the specific case are suitable for being associated with the pelvis-hip joint of the user. Such articulated modules 21 and 22 are for example of the type described in the previous patent application of the same aforementioned owner, ie WO2017216663. In greater detail, the exoskeletal articulated modules 21 and 22 are each materialized by a kinematic chain which allows the transmission of rotary motion between an active rotating element materialized by each of the motion input pulleys 21a and 22a and a distal rotating element. The two rotating elements have axes that can assume any relative orientation. The distal rotating element is also materialized by a respective pulley, shown in the figures and indicated with references 210a and 222a. The first rotating element is therefore able to rotate around its own rotation axis X. The second rotating element is in turn able to rotate around its own Y axis of rotation.

The kinematic chain further comprises a plurality of connecting elements 21b, 22b each of which comprises at least one passage having at least one rotating element; each connection element also includes at least one interface designed to connect the connection element to an adjacent one and to one of the rotating elements, generating a rotational constraint around its own axis of rotation Z.

The chain then comprises a transmission element (not visible), such as a cable or a belt, capable of developing along a determined path to transmit a rotary motion between the two rotating elements.

Therefore, the kinematic chain is able to pass between an adjustment configuration in which each connection element is able to rotate around its own axis of rotation Z to adjust its angular position with respect to an adjacent connection element or to one of the elements. rotation, and a transmission configuration in which when the first rotation element rotates around its axis of rotation X, the distal rotation element performs a proportional rotation around its axis Y; in the transmission configuration, each connection element is designed not to rotate around its Z axis of rotation.

The robot object of the invention obtains various advantages in terms of overall weight reduction and structural complexity. In particular, thanks to the under-implementation of the two or more robot joints, the latter not only obtains a structural simplicity that currently known robots do not have, but is also lighter and less bulky, while maintaining the same functionality and reliability.

Furthermore, the cost, weight and size ratio with the same number of moved and / or movable joints is significantly lower than that of the robots object of the state of the art.

It is also possible to provide braking means in association with the under-actuation group and in particular with each of its outputs. The braking means, such as for example but not limited to disc brakes, have the purpose of modulating the flow of power between one or the other output of the group itself according to the movement that the user must perform. Said braking means therefore obtain a further level of control since by acting on one or both brakes associated with the two outputs, they can further distribute and / or distribute the motion given out by the motion distribution means.

The association of a SEA-type architecture to a motion distribution element then determines further advantages in particular as regards the control of the wearable robot even in the face of external perturbations caused by movements exercised by the user himself. As described above, thanks to the implementation of the SEA it is possible to make the robot "transparent" to this type of stress, thus leaving the user great freedom and ability to move even when the robot is worn.

Thanks to the back exoskeleton as described, it is also possible to assist the movement of the entire spinal column of the user starting from a single motion drive; in fact, thanks to the transmission of motion along the back kinematic chain due to the interaction between the at least one cable and the pulleys, it is possible to operate the plurality of exoskeletal links starting from a single motion input.

Furthermore, the association of this back exoskeleton with the articulated exoskeletal modules of the pelvis-hip as described and with the underactivation group (therefore comprising in turn means of actuation and an element for distributing motion in differential mode) allows to have a complex robotic architecture starting from a single actuator, with an evident reduced structural complexity and overall weight.

The present invention has been described with reference to a preferred embodiment thereof. It is to be understood that there may be other embodiments that refer to the same inventive core, all falling within the scope of the claims set out below.

Claims (12)

CLAIMS 1. An active robot adapted to be worn by a user, the robot comprising at least two articulated exoskeletal modules (20, 21, 22) adapted to correspond to respective mono- or poly-articular body joints of said user when the robot itself is worn , said robot further comprising actuation means (10) adapted to actuate at least two of said articulated modules; in which one of said articulated modules is a poly-articular kinematic chain (20), comprising a single motion input powered by said actuation means and adapted to correspond with the user's spine. 2. Active wearable robot according to claim 1 further comprising an underactivation unit (1) interfaced with said two or more articulated modules (20, 21, 22) said underactuation unit comprising: - actuation means (10) which define an output of primary motion (100); - at least a first motion distribution element (11) connected to said primary motion output (100) to receive the motion generated by them at the input and distribute it in differential mode through at least two derived motion outputs (110, 111); wherein at least one of said two or more articulated modules (20, 21, 22) is associated with each of said two derived motion outputs (110, 111). Active wearable robot according to claim 2, wherein said motion distribution element is a differential gear (11). 4. Wearable active robot according to claim 2, wherein said motion distribution element is a hydraulic differential materialized by a tubular bifurcation which defines a fluid inlet and at least two fluid outlets. 5. An active wearable robot according to claim 3, in which sensor means (13) are arranged downstream of said actuation means, suitable for detecting the torque delivered by said primary motion output. 6. Wearable active robot according to claim 5, wherein said sensor means comprise a transmissive element (130) with torsional elastic response and at least one position sensor for determining the torsional bending of said transmissive element. A wearable active robot according to any one of claims 2 to 6, wherein one of said derivative motion outputs (110, 111) is connected to a second differential mode motion distribution element (12), said second driving element motion distribution in differential mode by defining two further derived motion outputs. 8. Wearable active robot according to claim 7, in which said two or more articulated modules (21, 22) also comprise two articulated kinematics adapted to correspond with a pelvis-hip joint of the user. 9. Active wearable robot according to any one of the preceding claims, wherein said chain comprises a number of exoskeletal rotational joints (20d) each of which is such as to allow relative rotation between two exoskeletal links (20b) adjacent to it around its own axis of rotation. 10. Wearable active robot according to claim 9, wherein at each exoskeletal rotoidal joint of said kinematic chain a pulley (20a ') adapted to rotate around a corresponding axis of rotation is arranged, the kinematic chain further comprising and at least one inextensible cable (20c) in contact by friction with each pulley (20a ') and constrained to an exoskeletal link at the end of said kinematic chain opposite to a connection end integral with the user 11. Wearable active robot according to claim 10, wherein said actuation means are adapted to pull said at least one cable (20c) so as to cause said exoskeletal links (20b) to rotate around the respective exoskeletal rotoidal joints (20d). 12. Active wearable robot according to claim 11, wherein said kinematic chain comprises two or more cables (20c) can be provided being adapted to be alternately tractionated so as to bring said exoskeletal links to rotate around the respective exoskeletal rotoidal joints (20d) clockwise and / or counterclockwise.