Patent Publication Number: US-2022218552-A1

Title: Load compensation device, in particular of gravitational loads, applicable to exoskeletons

Description:
TECHNICAL FIELD 
     The present invention relates to a load compensation device, in particular for compensating gravitational loads. In a preferred and non-limiting application, the present invention also relates to a related exoskeleton. 
     In general, the present invention finds non-limiting applications in the field of handling apparatuses and in the field of physical activity and rehabilitative exercise apparatuses. 
     PRIOR ART 
     In the last years, exoskeletons have found various applications which are mostly related to the biomedical and industrial fields. 
     In the biomedical field, the exoskeletons are designed to enhance the individual&#39;s physical and motor abilities, further compensating the effect of the force of gravity thus reducing the physical effort and the individual exertion. In particular, in the biomedical field, exoskeletons are used in the field of motor function recovery and assistance. The recovery relates to the rehabilitation of a patient, while the “assistance” relates to the simple case of aid, wherein the motor abilities of a user are irreversibly compromised. 
     In the industrial field, exoskeletons are mainly used in the manufacturing and building industries, in which the operators have to maintain uncomfortable postures or have to move or lift heavy loads; furthermore, exoskeletons are also used as aid for the healthcare workers. In general, in this industrial field, the exoskeleton is designed to relieve the effort of one or more body parts. 
     In exoskeletons, the load compensation is carried out via different technologies which can be categorized as “passive” or “active”: the “passive” compensation technology uses a set of one or more elastic elements, which are loaded during the motion and release deformation energy during a motion in opposite direction; instead, the “active” compensation technology uses a motor-driven drive, typically of the electric type; other types of drives can provide piezoelectric actuators, SMA (“Shape-Memory Alloys”), pneumatic drives or electroactive polymers. 
     The passive compensation technology has the advantage of not requiring an external power supply, allowing lighter, more compact exoskeletons, which are also free from electronic power supply, to be obtained. Indeed, the passive compensation systems usually consist of kinematic chains of elastic elements, which support by deformation the user&#39;s weight. 
     However, exoskeletons with passive compensation cannot apply total compensation to the loads, for any position taken by the user, but have only one balance point. Furthermore, during the loading motion, the user has to produce force in order to load the elastic elements. 
     Instead, the active compensation technology requires an external power supply, electronics and control logics. Disadvantageously, the electric drive motors are bulky, causing the exoskeleton to be heavier and less ergonomic than the passive one. Furthermore, in case of high energy consumptions, the exoskeleton cannot be efficiently powered by a light and compact battery system. 
     For these reasons, the most widespread exoskeletons are of the passive compensation type both in the industrial field and in the biomedical field. 
     Examples of exoskeleton systems and gravitational load compensation devices of the active type are provided in documents KR20160071661, EP3278938A1, WO2017161257 and WO2015106278, which describe solutions including actuators. 
     Examples of exoskeleton systems and gravitational load compensation devices of the passive type are provided in documents KR20120082221, WO2015147584, CA2952403, US20120184880, CA2544645, WO2018165399A1, EP2861387, which include elastic elements, also of the adjustable type, proposed in exoskeletons and in devices which are wearable by a user. 
     A further example of gravitational load compensation device is provided in document EP3342390A1, which refers to an apparatus to support a limb comprising passive force elements connected to a wearable element and support active elements actuated by traction actuators with motor-driven cable. However, also the device known from EP3342390A1, although realizing a hybrid structure between active and passive systems, has disadvantages and limitations of application. 
     SUMMARY OF THE INVENTION 
     Object of the present invention is to solve drawbacks of the prior art. 
     Further particular object of the present invention is to present a device which has reduced energy consumptions and can thus efficiently be power supplied also with a portable battery system. 
     Further particular object of the present invention is to allow variable load compensation, in particular of gravitational loads, for any position taken by the user. 
     Further particular object of the present invention is to present a device which is less bulky than those entirely active, so as to obtain lighter and more ergonomic exoskeletons. 
     These and other objects are achieved by a load compensation device and a related exoskeleton according to features of the appended claims, which form an integral part of the present description. 
     An idea underlying the present invention is to provide a load compensation device comprising:
         an assisted joint configured to be constrained to a support structure;   a main rod comprising a proximal end connected to the assisted joint, and further comprising a distal end configured to be stressed by an applied load;   an auxiliary rod comprising a first end and a second end, the first end being hinged on the main rod for rotating the auxiliary rod with respect to the main rod, and the second end being movable on a plane on which the applied load lies;   an elastic element configured to provide an elastic force which acts between the second end of the auxiliary rod and the distal end of the main rod;   a regulation system configured to modify a distance between the second end of the auxiliary rod and the assisted joint, so as to vary a preloading of the elastic element;       

     wherein the elastic element is configured to provide the elastic force based on a kinematic configuration of the load compensation device, so as to compensate the applied load in a component thereof which is transverse to the main rod. 
     In short, the load compensation device according to the present invention is designed with the purpose to completely identify and compensate, with minimal energy consumptions and bulkiness, the effect of a force, for example of a gravitational force, which acts on a main rod which represents the hooking point of the load compensation device to a structure of a system in which it is inserted, for example of an exoskeleton or of a robotic arm. 
     The load compensation device of the present invention then comprises a mechanical structure provided with suitable sensors and control logics, wherein a preloaded elastic element provides the necessary compensation force. 
     Advantageously, the present invention allows realizing a load compensation device which realizes a hybrid technology, designed to apply a compensation of the loads which adapts to the movements of the user, while guaranteeing a high compactness and low energy consumptions. 
     In particular, the load compensation device according to the present invention allows merging the positive aspects of the passive and active technologies inside a unique device which can be scalable to any type of apparatus or exoskeleton. 
     The load compensation device according to the present invention can also advantageously be used in different fields, such as for example the industrial robotics, the lifting or handling systems, to develop more compact and less energy-consuming apparatuses. 
     Preferably, the load compensation device comprises a movable regulation element, associated with the support structure. In particular, preferably, the movable regulation element provides a regulation rod and linear actuator system, or a cable and motor-driven pulley system. 
     Preferably, the elastic element is at least indirectly connected to the second end of the auxiliary rod. In particular, preferably, the load compensation device comprises a compensating cable which connects the second end of the auxiliary rod to the elastic element, with a pulley in proximity of the distal end of the main rod. 
     The load compensation device, which is the object of the present invention, could be applied to one or more joints of an exoskeleton or a robotic arm, making the solution applied to multiple degrees of freedom. 
     A further idea underlying the present invention is thus to provide an exoskeleton comprising one or more load compensation devices. 
     Further characteristics and advantages will be more evident from the detailed description made hereinafter, of preferred non-limiting embodiments of the present invention and from the dependent claims, which are outlining preferred and particularly advantageous embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is illustrated with reference to the following figures, provided by way of a non-limiting examples, wherein: 
         FIG. 1  illustrates an example of an upper limb which holds an object subjected to a load induced by gravitational force. 
         FIG. 2  illustrates an exoskeleton engaging an upper limb and comprising a load compensation device according to the present invention. 
         FIG. 3  illustrates a first embodiment of a load compensation device according to the present invention. 
         FIG. 4 a    and  FIG. 4 b    illustrates exemplary performances of a load compensation device according to the present invention. 
         FIG. 5  illustrates a second embodiment of a load compensation device according to the present invention. 
         FIG. 6  illustrates a third embodiment of a load compensation device according to the present invention. 
         FIG. 7  illustrates an exoskeleton involving pelvis and lumbar spine and comprising a load compensation device according to the present invention. 
         FIG. 8  illustrates a fourth embodiment of a load compensation device according to the present invention. 
         FIG. 9  illustrates a fifth embodiment of a load compensation device according to the present invention. 
     
    
    
     In different figures, similar elements will be identified by similar reference numbers. 
     DETAILED DESCRIPTION 
     In preferred embodiments, the load compensation device according to the present invention is used for compensating the effect of gravitational loads in exoskeletons or robotic arms. In particular, the present invention is pertaining to exoskeletons applicable to multiple joints of the human body, such as shoulder, hip in favour of the lumbar spine, the knee, and to robotic arms. The present invention will refer to this non-limiting application of the load compensation device according to the present invention. 
     In this exemplary application, most of the effort required to carry out a movement with the upper limbs is used to overcome the gravitational effect which can be identified with a torque which acts on the arm itself. Accordingly, the shoulder is the joint which is mainly stressed. The exoskeletons are devices designed exactly to relieve the effort of the user who is wearing it, multiplying the force capabilities. In particular, the load compensation device according to the present invention is designed to be integrated inside exoskeletons, for upper limbs or also lower limbs, at a joint of a user. Similar applications can be carried out, by extension, to robotic arms. 
       FIG. 1  illustrates an example of an upper limb  1  which holds an object  11  subjected to a load induced by the gravitational acceleration “g”. 
     The load “g” which acts on the object  11  becomes particularly relevant for the flexo-extension movement of the shoulder of the limb  1 : this is the case of the “pick &amp; place” movement which is carried out in many industrial fields, such as in the one of large retailer logistic and of manufacturing. 
     The limb  1  can be schematized as being composed of rigid bodies  6  and  8 , of load  11  and of masses  7 ,  9 ,  10  and  11 , respectively. The rods  6  and  8  are connected with each other by a hinge  5  and constrained to the ground via a hinge  3 . This system represents the scheme of the user in the vertical plane. Therefore, the compensation torque applied to the body  6 , which is necessary to compensate the gravitational effect which acts on the system and which is caused by the gravitational acceleration “g”, will be in function of the position thereof taken in the plane, identified by the angles  2  and  4 , by the geometric values of the rods  6  and  8  and by the corresponding masses  7 ,  9 ,  10  and  11 . The gravitational effect can thus be understood as a resulting torque on the rod  6  caused by the weight forces acting on the barycentres of the bodies  7 ,  9 ,  10  and  11 . 
       FIG. 2  illustrates an exoskeleton  100  engaging the upper limb  1  and comprising a load compensation device  201  according to the present invention. 
     As already described, a non-limiting example of application of the present invention is the compensation of gravitational loads acting on upper limbs during the flexo-extension motion of the shoulder, that is the rotation motion of the shoulder in the vertical plane, as already illustrated in  FIG. 1 , where the arrow  2  represents the rotation of the shoulder and “g” the gravity vector. In this case, the exoskeleton  100  is configured to compensate the gravitational loads which the shoulder of the user is subjected to. 
     The application of the load compensation device  201  to the exoskeleton  100  is exemplified to provide a hybrid technology in the case of exoskeletons for upper limbs and for “pick &amp; place” activities. 
     The load compensation device  201  is connected to a support structure  102  onto which the forces are released. The compensation force is transferred from the device  201  to the limb via an armrest  103  during the flexo-extension motion of the shoulder which is imposed by the user around the hinge  3 . The belt  104  preferably contains the electronic components and the power-supply batteries of all active parts, while the strip  105  contains a sensor for detecting the relative rotation between arm and forearm. 
     In general, the load compensation device is associated, in the exoskeleton  100 , with a battery to supply power to the regulation system, which will be further described, with a plurality of sensors and with at least a processor. 
     In other embodiments, the load compensation device could be applied to a robot or to a lifting apparatus or to a load handling apparatus, with an assisted joint configured to be constrained to a support structure, where there is a main rod, with the purpose of compensating a transverse component of a load applied to the main rod. 
       FIG. 3  illustrate a first embodiment of a load compensation device  301  according to the present invention. 
     The load compensation device  301 , which is in particular configured to compensate gravitational loads, comprises an assisted joint  302 , which is configured to be constrained to a support structure  303 . 
     The load compensation device  301  further comprises a main rod  304  comprising a proximal end  305  connected to the assisted joint  302 , and further comprising a distal end  306  configured to be stressed by the applied load, for example the already-described load  11 . 
     The load compensation device  301  further comprises an auxiliary rod  307  comprising a first end  308  and a second end  309 . The first end  308  is hinged on the main rod  304  for rotating of the auxiliary rod  307  with respect to the main rod  304 . The second end  309  is instead movable on a plane on which the applied load  11  lies, which the load compensation device  301  is configured to compensate. 
     In particular, the auxiliary rod  307  is projecting outside of the main rod  304  in a direction opposite to a prevalent direction of the applied load  11 . In particular, in the exemplary configuration of  FIG. 3 , the main rod  304  is horizontal and the auxiliary rod  307  is projecting outside of the main rod  304  in an essentially vertical and “upwards” direction, therefore on the opposite side of the prevalent direction of the applied load  11  which is “downwards”. 
     Preferably, the first end  308  of the auxiliary rod  307  is hinged on the main rod  304  in an intermediate position between the proximal end  305  and the distal end  306  of the main rod  304 . 
     In particular, exactly the distal end  306  of the main rod  304  corresponds to a brace of a movable structural element subjected to variable loads, such as the already-described element  103 . 
     In general, the length of the rods  304  and  307 , the distances between the constraints and the general kinematic configuration of the load compensation device are determined in function of the desired compensation performances and of the energy and bulk constraints of the overall system. 
     The load compensation device  301  further comprises an elastic element  310 , which is configured to provide an elastic force which acts between the second end  309  of the auxiliary rod  307  and the distal end  306  of the main rod  304 . 
     In a preferred embodiment, the elastic element  310  comprises a traction or compression helical spring. In a variant, the elastic element could be a band made of rubber or of an elastic material which is suitable for the purpose. 
     Preferably, the elastic element  310  is at least indirectly connected to the second end  309  of the auxiliary rod  307 . 
     In a preferred embodiment, such as the one represented in  FIG. 3 , the elastic element  310  is indirectly connected to the second end  309  of the auxiliary rod  307 , in particular, providing a compensating cable  311  which directly connects the second end  309  of the auxiliary rod  307  to the elastic element  310 . 
     Preferably, the elastic element  310  develops axially and is essentially parallel to the main rod  304 ; thereby, the load compensation device may be more compact and it is possible to insert an elastic element with higher stiffness. The load compensation device  301  further comprises a pulley  312  in proximity of the distal end  306  of the main rod  304 , wherein the compensating cable  311  engages the pulley  312 . 
     In a variant, the elastic element  310  could be directly connected to the second end  309  of the auxiliary rod  307 , by directly connecting the distal end  306  to the second end  309  being interposed between them, without the need of a compensating cable, as it will be described with reference to  FIG. 9 . 
     The load compensation device  301  further comprises a regulation system  313  configured to modify a distance between the second end  309  of the auxiliary rod  307  and the assisted joint  302 , so as to vary a preloading of the elastic element  310 . 
     The elastic element  310  is configured to provide an elastic force based on a kinematic configuration taken by the load compensation device  301 , so as to compensate the applied load  11  in a component thereof which is transverse to the main rod. 
     In this sense, the regulation system  313  is preferably configured to minimize a difference between the transverse component of the load  11  to be compensated, and an opposed transverse component provided by the elastic force of the elastic element  310 . 
     The operating principle carried out by the load compensation device  301  is as follows: at any position taken by the user (exoskeleton or robotic arm), suitable control logics, via sensors and processors, process the gravitational torque/force which acts on the assisted joint  302 . They thus process the control action to be sent to the regulation system  313  such that the latter will modify the preloading of the elastic element  310  through the articulated system of the arms  304  and  307 , such that the compensation force is equal to the one of the gravitational effect. 
     In particular, the load compensation device  301  further comprises a plurality of sensors (not shown) configured to measure an absolute position of the main rod  304  and further to measure or obtain a torque which stresses the assisted joint  302  as a result of the applied load  11 . Furthermore, the load compensation device  301  further comprises at least a processor (not shown) operatively connected to the plurality of sensors and to the regulation system  313 , such processor being configured to calculate the preloading of the elastic element  310  so as to counterbalance the torque which stresses the assisted joint. 
     Preferably, the abovementioned processor is further configured to modulate the elastic force provided by the elastic element  310  in function of a dynamic trajectory which is measured by the plurality of sensors, in order to second a movement which is desired by the user of the exoskeleton or required by the programming of the robot. 
     It is provided an example of a regulation process which can be carried out at any position taken by the user in the vertical plane, such as the one implemented by the control logics and by the sensors to manage the working cycles of the load compensation device  301 . 
     A single exemplary working cycle can be summarized by the following operation flow:
         Sensors provide position measurements and send them to the control logics.   The control logics calculate the position taken by the user and the corresponding gravitational action which acts thereon, expressed as a torque with respect of the reference assisted joint  302 . In addition, preferably, the control system processes the movement dynamics and the type of carried-out trajectory.   A processor calculates a deformation which has to be applied to the elastic element  310  in order to obtain a torque which counterbalances the gravitational action.   A processor processes the control action to be sent to the regulation system  313  which allows the desired deformation of the elastic element  310  to be obtained by resolving the kinematics of the articulated system consisting of the rods  304  and  307 .       

     Preferably, such control is designed to modulate the actuation force in function of the trajectory and dynamics imposed by the user while carrying out an activity, so as to second the user intention in an application to an exoskeleton  100 . 
     As already described, the regulation system  313  is configured to modify a distance between the second end  309  of the auxiliary rod  307  and the assisted joint  302 , so as to vary a preloading of the elastic element  310 . In general, the regulation system  313  is further configured to vary a relative angle between the main rod  304  and the auxiliary rod  307 . 
     For this purpose, the regulation system  313  comprises a movable regulation element  314  associated with the support structure  303 . 
     Preferably, the regulation system  313  further comprises a regulation rod  320  which connects the movable regulation element  314  to the second end  309  of the auxiliary rod  307 . Preferably, the movable regulation element  314  comprises a linear actuator  321  onto which the regulation rod  320  is hinged. 
     Preferably, the linear actuator  321  is movable along a ramp element  322  which is constrained to the support structure  303 . 
       FIG. 4 a    and  FIG. 4 b    illustrate exemplary performances of a load compensation device according to the present invention. 
     In particular,  FIG. 4 a    illustrates a comparison between torques at the joint which are required from the user in function of the rotation angle of the main rod  304  around the assisted joint, without the device of the present invention (line  400 ) and with the load compensation device  301  (line  401 ). 
     It can be noted that the effort required from the user is almost completely null in case of using the device (line  401 , for any value of the angle). 
     In particular,  FIG. 4 b    illustrates a different situation, wherein it is assumed that the exoskeleton  100  is equipped with a motor which controls the rotation of the assisted joint  302  instead of the user, by supplying a torque, without the device of the present invention (line  402 ) and with the load compensation device  301  (line  403 ). 
     It can be noted how the total power (calculated by assuming that the angular velocity is constant) in case of exoskeleton  100 , which is provided with the load compensation device of the present invention (line  403 ), is almost null along the entire working field, as compared to the power in case of active exoskeleton with motor but without the device of the present invention (line  402 ). 
     The exemplified performances demonstrate that the load compensation device of the present invention is able to almost completely compensate the gravitational effect, in the entire working field, with minimum energy consumptions. 
     For this reason, the load compensation device of the present invention allows a lighter and less energy-consuming motor to be used, in favour of an overall lighter and more efficient system. 
       FIG. 5  illustrates a second embodiment of a load compensation device  501  according to the present invention. 
     The load compensation device  501  essentially comprises the elements already described in relation to the embodiment  301  presented with reference to the  FIG. 3 . 
     Compared to the already-described embodiment  301 , the load compensation device  501  provides different overall geometries implying slightly different kinematic characteristics which allow load compensation suitable for a specific use. 
     Furthermore, compared to the already-described embodiment  301 , the load compensation device  501  provides a linear actuator  321  which is moving on a different ramp element  522 , which is differently sloped and is not directly connected to the assisted joint  302 , but it is anyway connected to the support structure  303 . 
     In other words, the load compensation device  501  provides a regulation system  313  which always comprises a movable regulation element  314  associated with the support structure  303 , and wherein the linear actuator  321  is movable along a different ramp element  522  constrained to the support structure, wherein the ramp element  522  has a determined slope based on different desired kinematic characteristics for the load compensation device  501 . 
     The  FIG. 6  illustrates a third embodiment of a load compensation device  601  according to the present invention. 
     The load compensation device  601  essentially comprises the elements already described in relation to the embodiment  301  presented with reference to the  FIG. 3 . 
     Therefore, the load compensation device  601  employs the same operating principle described in relation to the previous embodiments  301  and  501 , but it uses a different regulation system  613  inside the hybrid mechanical structure. 
     In particular, the regulation system  613  further comprises a cable  620  which connects the movable regulation element  614  to the second end  309  of the auxiliary rod  307 . 
     In this embodiment of the regulation system  613 , the movable regulation element  614  comprises a motor-driven pulley  621  on which the cable  620  is adapted to wind or unwind. Thereby, the regulation system  613  is configured to modify a distance between the second end  309  of the auxiliary rod  307  and the assisted joint  302 , so as to vary a preloading of the elastic element  310 . In general, the regulation system  613  is further configured to vary a relative angle between the main rod  304  and the auxiliary rod  307 . 
     Preferably, the motor-driven pulley  621  is in a fixed position with respect to the assisted joint  302 , and a second distance between the motor-driven pulley  621  and the assisted joint  302  is determined based on desired kinematic characteristics of the load compensation device  601 . 
     In other words, in this embodiment of the regulation system  613 , the linear actuator  321  is replaced by a rotary actuator or motor  621 , while the regulation rod  320  is replaced by a cable  620  which winds the motor-controlled pulley  621  up. 
       FIG. 7  illustrates an exoskeleton  700  engaging pelvis and lumbar spine and comprising a load compensation device  701  according to the present invention. 
     In this embodiment of the load compensation device  701 , it is applied to exoskeletons for lumbar spine. 
     The load compensation device  701  is connected to a support structure  702  onto which the forces are released. The compensation force is transferred from the device  701  to the limb via an element  704 , during the motion of the leg imposed by the user around the hinge  3 . The element  704  itself preferably contains the electronic components and the power supply batteries of all the active parts, while there are sensors for detecting the relative rotation between  703  and  704 . 
     In general, the load compensation device is associated, in the exoskeleton, to a battery to supply power to the regulation system, a plurality of sensors and at least a processor. 
       FIG. 8  illustrates a fourth embodiment of a load compensation device according to the present invention. 
     The load compensation device  701  is applied to the exoskeleton  700  in order to relieve the effort in the area of the lumbar spine. In this case, the assisted joint  302  is the one of the pelvis. The support structure, on which the load compensation device  701  clasps, is composed of two parts, one which clasps on the upper part of the leg and one which clasps to the pelvis. 
     The load compensation device  701  follows the same implementation of the already-described load compensation device  501 . 
       FIG. 9  illustrates a fifth embodiment of a load compensation device  901  according to the present invention. 
     The load compensation device  901  comprises some of the elements already described in relation to the embodiments  301  and  501  presented with reference to the  FIG. 3  and  FIG. 5 . 
     In particular, the load compensation device  901  comprises an assisted joint  302  configured to be constrained to a support structure  303 . 
     The load compensation device  901  further comprises a main rod  304 , comprising a proximal end  305 , connected to the assisted joint  302 , and a distal end  306  configured to be stressed by the applied load  11 . 
     The load compensation device  901  further comprises an auxiliary rod  307  comprising a first end  308  and a second end  309 . The first end  308  is hinged on the main rod  304  for rotating the auxiliary rod  307  with respect to the main rod  304 . The second end  309  is movable on a plane on which the applied load  11  lies. 
     The load compensation device  901  further comprises an elastic element  910  configured to provide an elastic force which acts between the second end  309  of the auxiliary rod  307  and the distal end  306  of the main rod  304 . 
     In particular, the elastic element  910  is a tension spring which directly connects the second end  309  with the distal end  306 . In a preferred embodiment, the elastic element  910  comprises a helical spring, but it could also be a band made of rubber or of an elastic material which is suitable for the purpose. 
     In a variant, the tension spring could connect outer portions of rods  304  and  309 , without directly connecting their ends. 
     The load compensation device  901  further comprises a regulation system  313  configured to modify a distance between the second end  309  of the auxiliary rod  307  and the assisted joint  302 , so as to vary a preloading of the elastic element  910 . 
     The regulation system  313  preferably corresponds to the embodiment already described with reference to  FIG. 5 , with a linear actuator  321  which is moving on a ramp element  522 . 
     In general, the elastic element  910  is configured to provide the elastic force based on a kinematic configuration of the load compensation device  901 , which is determined by the position of the main rod  304  and the auxiliary rod  307 , and by the preloading of the elastic element  910 . 
     In that, the load compensation device  901  is capable of compensating the applied load  11  in a component thereof which is transverse to the main rod  304 . 
     INDUSTRIAL APPLICABILITY 
     The present invention allows loads to be efficiently compensated, in particular gravitational loads. 
     The load compensation device according to the present invention can be integrated inside exoskeletons which are particularly designed for industrial applications in which a user has to carry out strenuous manual or generally body-wearing operations, and for both rehabilitation and assistive biomedical applications. 
     In this sense, the load compensation device according to the present invention, which is integrated in an exoskeleton, allows a load reduction in different joints, such as shoulder, lumbar spine, knee, hip, etc. 
     Furthermore, the load compensation device according to the present invention can also be integrated into robotic arms. 
     Considering the description herein reported, the skilled person will be able to conceive further modifications and variations, in order to meet contingent and specific needs. 
     The embodiments herein described are therefore to be considered as illustrative and non-limiting examples of the invention.