FR3004105A3 - RECONFIGURABLE EXOSKELET DEVICE FOR ANKLE - Google Patents

Abstract

The present invention relates to a reconfigurable, parallel mechanism-based force reaction exoskeleton device for the human ankle. The main purpose of the device is to be used as a balance / proprioception training device, while the exoskeleton device can also be used to accept joint amplitude (RoM) / reinforcement exercises. This device is also used for the exercises of metatarsophalangeal joints. The portable and reconfigurable ankle measurement and therapy device for ankle can support two different types of exercises, ie RoM / reinforcement exercises and balance / proprioception exercises. independently of each other, and comprises a base platform (3) facing the operator's leg, a movable platform (2) facing the operator's foot, a connecting member (4) which connects the base platform (3) and the mobile platform (2), and a hinge element (5) which connects the connecting element (4) to the base platform (3).

Description

BACKGROUND OF THE INVENTION The present invention relates to a reconfigurable, ungrounded force feedback exoskeleton device based on a parallel mechanism for a human ankle. The main purpose of the device is to be used as a balance / proprioception training device, while the exoskeleton device can also be used to accept joint amplitude (RoM) / reinforcement exercises. This device is also used for exercises of metatarsophalangeal joints. The goal of rehabilitation is to recover physical, sensory and neural abilities that have been impaired due to illness or injury. Rehabilitation of the ankle is commonly required after ankle sprain, one of the most common injuries in sport and in everyday life [1]. Loss of functional capacity, ability to withstand weight and stability of the ankle joint may also be felt after neurological injury following a stroke and contractures and deformities following a stroke. cerebrovascular disease. Physiotherapy exercises are essential to acquire ankle joint amplitude (RoM) again, to help strengthen the muscles to support the weight, to promote a better awareness of the position of the joint (proprioception), to ensure neural integrity and to recover dynamic balance. Rehabilitation of an ankle injury is usually treated by three sequential phases of exercise [2], [3]. The exercises in the first phase focus primarily on the possibility of a complete RoM of the ankle and then on the strengthening of the ankle muscles. Once the required RoM and flexibility are obtained, and the muscles are robust enough to support the partial weight without inducing pain, the intermediate phase of the therapy can be started, focusing on improving the ability to proprioception using static balance exercises. During the final phase of therapy, more advanced dynamic balance exercises are practiced. Conventional rehabilitation devices used to assist physiotherapy are simple passive equipment, such as elastic bands and ankle rehabilitation pumps for strengthening and stretching exercises; balance boards and foam rollers for proprioception and balance exercises. RoM exercises are usually performed manually by a physiotherapist. Although these types of equipment are simple and cost-effective, these conventional devices do not collect quantitative measurements of patient progress, do not monitor patient history for re-evaluation, and do not obtain personalized interactive treatment protocols. Physiotherapists are needed to physically handle movement therapy and to care for the patient when doing exercises with these devices. Currently, rehabilitation exercises are done using robotic devices.

The assistance of repetitive and physically complex rehabilitation exercises using robotic devices not only helps to remove the physical burden of movement therapy for physiotherapists, but also reduces the costs of application. In addition, robot-assisted rehabilitation provides quantitative measures of patient progress and can be used to perform personalized interactive treatment protocols. The beneficial effects of robot-assisted rehabilitation protocols have been demonstrated compared to conventional therapy by clinical trials in the literature [4]. Recognizing the need for robot-assisted rehabilitation devices for ankle physiotherapy, several designs have been proposed to date. Girone and associates have proposed a force feedback interface, called Rutgers Ankle, based on Stewart's platform [5]. In [6], an interactive training protocol based on a virtual reality was implemented using the Rutgers Ankle for orthopedic rehabilitation. The system has also been studied [7] and [8] through several case studies. Remote ankle rehabilitation at home was treated in [9], while in [10], the system was extended to a double Stewart platform for use in gait simulation and rehabilitation. In [11], Dai and Associates propose another robotic device to treat sprained ankles. Unlike the Stewart platform design, this device has just enough degrees of freedom (DoF) to cover the human ankle guidance work space. Kinetic analysis presented in this reference highlights the importance of using a central spacer to obtain greater resistance from the device. In [12], Agrawal and Associates propose an ankle orthosis for robot-assisted rehabilitation and present the kinematic analysis and tuning of the proposed mechanism. Similarly, in [13], the "Anklebot" was proposed by Roy and Associates to help recover the function of the ankle. This device can also be used to measure the rigidity of the ankle, which is a powerful biomechanical factor for locomotion.

Syrseloudis and Emiris have studied RoM in translation and rotation of the human ankle and foot by experiments on human patients, and conclude that a parallel tripod mechanism with an additional axis of rotation in series is the most suitable for conforming to foot kinematics in relation to the human ankle [14]. In [15] Yoon and Ryu proposed a four parallel DoF hybrid parallel-based heel device and presented the kinematic analysis of the new device. In [3] and [16], this work has been extended to allow the device to be reconfigured to support several distinct modes of exercise. An object of the invention is therefore to propose a device which has a reconfigurable design. Its implementation is simple and the device can be manufactured by assembling parts distributed commercially. Because of its reconfiguration feature, the device allows both RoM / reinforcement range exercises and balance / proprioception exercises. SUMMARY OF THE INVENTION According to one embodiment of the present invention, the device can cover the entire complex amplitude of the human ankle for RoM / strengthening exercises. The device can support the human weight during balance / proprioception exercises. The exercises of the metatarsophalangeal joints are also authorized via the reconfigurable design of the baseplate. According to one embodiment of the present invention, the device can be used as a clinical measurement tool. Lever movements, forces, and impedances of the ankle joint can be determined to assist diagnoses. According to one embodiment of the present invention, the device is ergonomic, allows the entire range of motion of the human ankle. The device is lightweight and can be worn; therefore, he is portable. The device is inherently healthy because of the choice of its actuators.

According to one embodiment of the present invention, the device has a higher tuning performance than similar devices due to its parallel kinematic structure and optimized bandwidth. According to one embodiment of the present invention, the device supports complex movements of the foot and is not limited to a single degree of freedom as is the case with many existing designs. According to one embodiment of the present invention, the device is programmed to guide, assist, or resist the patient during physical therapy and is implemented with a computer system. The levels of assistance and resistance are adjustable by software. The device can also be programmed to evaluate the parameters of the ankle joint, such as tonicity and ankle impedance. Aspects of the device according to the present invention are related to reeducation robots, robot assisted rehabilitation, physical therapy devices, force feedback exoskeletons, haptic interfaces for medical treatment, clinical measurement devices, systems ankle rehabilitation, ankle braces, rehabilitation devices for ankle physiotherapy, devices for evaluating ankle function, determination of ankle impedance. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the device; Fig. 2 is a side view of the device in a 3UPS configuration; Figure 3 is a perspective view of the device that behaves like a 3RPS mechanism; Fig. 4 is a perspective view of the device when it behaves like a 3UPS mechanism (the central linkage represents the human foot and ankle); Figure 5 is a perspective device view in an unlocked position; Figure 6 is a perspective view of the hinge member used in the device in the locked position; Fig. 7 is a flowchart of the reaction torque observer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description of the preferred embodiments is purely exemplary in nature and is in no way intended to limit the invention, its application or its uses. An ankle measurement and therapy device for the ankle (1) comprising: a movable platform (2) facing the operator's foot, a base platform (3) facing the leg of the operator operator, a connecting element (4) which connects the base platform (3) and the mobile platform (2). The exoskeleton device (1) further comprises a hinge member (5) which connects the connecting member (4) to the base platform (3). With the aid of said hinge element (5), the exoskeleton device (1) can support two different types of exercises, that is to say the RoM / reinforcement exercises and the balance exercises. / proprioception independently of each other. The hinge element (5) can selectively be in different modes. In the preferred embodiment of the invention, it is switched between a universal joint and a rotoid joint. In the preferred embodiment of the invention, the connecting element (4) is connected to the mobile platform (2) using spherical joints. The ankle joint can be modeled as a kinematic chain in spatial series with two rotoid joints (RR), ie an upper ankle joint and an astragalocalcaneal joint. The upper ankle joint supports movement of dorsiflexion / plantar flexion in rotation, while the astragalocalcaneal joint supports the supination / pronation movement in rotation. The supination / pronation rotation is a complex movement that has both inversion / eversion and abduction / adduction components. The kinematic chain using the preferred embodiment of the invention is the closed kinematic chain (parallel mechanism). Said closed kinematic chain serves as an exoskeleton and allows and supports the natural movements of human joints when the device (1) is carried by the operator. The closed drive train offers compact designs with high rigidity and low effective inertia. Actuators of closed kinematic chains can be grounded or placed on parts of the mechanism that experience low accelerations. The closed drive train used in the present invention can be used as at least two different mechanisms using the hinge member (5). Thanks to this, the device (1) gains a reconfigurable property. In the preferred embodiment of the invention, it can be used as a 3UPS mechanism (universal, prismatic, spherical) and a 3RPS mechanism (rotoid, prismatic, spherical) independently of one another. In the preferred embodiment of the invention, the hinge member (5) is the reconfigurable hinge that can selectively be used in the unlocked or locked positions. In the unlocked position, the reconfigurable articulation (5) can rotate freely about two axes (A, B). The first axis (A) is tangential to the base plate (3) while the second axis (B) is perpendicular to the base plate (3). When the hinge (5) is not locked, sets of rotational joints function as a universal hinge rotating about said desired axes. When the second hinge axis (B) is locked, the reconfigurable hinge (5) is constrained to function as a rotoid hinge, which is free to rotate only about the first axis (A). Therefore, the reconfigurable articulation (5) allows to reconfigure a 3UPS mechanism into a 3RPS mechanism, and vice versa.

The connecting element (4) basically comprises a drive unit (6) and a movable element (7). The drive unit (6) can apply the necessary force to the movable member (7) so that the movable member (7) can move. In the preferred embodiment of the invention, the drive unit (6) is an electric motor while the movable member (7) is at least one extensible link.

In the case in which the closed kinematic chain is used in the form of a 3UPS mechanism, the reconfigurable articulation (5) is in the unlocked position, in other words, it is free to rotate about the desired axes ( A, B), and behaves like a universal articulation. In addition, the operator's leg behaves like a central link of the mechanism, in other words the operator's peg becomes an element of the mechanism. In the preferred embodiment of the invention, the mechanism is a symmetrical 3UPS mechanism where the universal joint (5) and the spherical joints are spaced at 120 ° along the circumference of the base platform (3) and the mobile platform (2). When worn by the user, the 3UPS mechanism attached to the human ankle has two degrees of freedom (DoF) corresponding to a coupled movement of the mobile platform (2) relative to the fixed base platform (3). The lengths of the extensible links (7) are actuated to adjust these DoFs. The movable platform (2) is at a distance z from the base platform (3) and has no translational movement transverse to the vertical axis through the base (2). Even when the operator is completely passive, the 3UPS mechanism with two DoFs has three actuated joints; therefore, it is a redundant mechanism. This redundancy can be exploited to increase the effective working space of the device (1), since the singularity resolution becomes feasible in the case in which the device (1) approaches the singularities in the workspace. In the case where the closed kinematic chain is used as a 3RPS mechanism, the reconfigurable hinge (5) is in the locked position, in other words, the rotational movement of the hinge (5) around the second axis (B) is prevented. The reconfigurable articulation (5) behaves like a rotoid joint and its axes of rotation are oriented along the tangents of the base platform (3). The base platform (3) is attached to the upper half of the calf of the leg through a passive rotoid joint to allow internal / external rotation of the foot. In the preferred embodiment of the invention, the mechanism is a symmetric 3RPS mechanism in which the rotoid joints (5) and the spherical joints are spaced at 120 ° along the circumference of the base platform (3) and the mobile platform (2). The 3RPS mechanism has three DoFs corresponding to the height z. The lengths of the extensible links (7) are actuated to adjust these DoFs. The mobile platform (2) has a limited translational movement transverse to the vertical axis passing through the base (3) and no singularity for limited values of the angles of the rotoid joint. When the closed drive train is in the 3UPS mode, the device (1) can be used as a RoM / reinforcement exercise device, whereas when in the 3RPS mode, it can be used (1) as a balance / proprioception exercise device.

The couplings between the exoskeleton device (1) and the operator are designed to be resilient to ensure safety and to allow for small articulation misalignments and modeling imperfections. The elasticity allows the relative movement of the human limb relative to the device (1) when the kinematics of the device (1) is in conflict in natural movement of the ankle. In one embodiment of the invention, the weight of the device (1) is distributed over the upper leg and the upper half of the calf using tight straps around the knee. In another embodiment of the invention, the weight of the device (1) can be distributed over the body by suspending the device (1) at the operator's shoulder. The exoskeleton device (1) further comprises a control unit (not shown in the figures), and at least two sensors (not shown in the figures). One of the sensors measures the length of the connecting element (4) while the second sensor measures the amount of axial rotation of the articulation element (5). The measured data of the elements are processed by the control unit to calculate the configuration of the device (1) and to estimate the forces acting on the latter (1). In particular, the forward kinematics of the device (1) is used to calculate the configuration of the mobile platform (2), while the dynamics of the device (1) is used with a reaction torque observer implemented by software to to estimate the forces acting on it (1). To estimate the parameters of the ankle, the lengths of the link (7) of the kinematic chain must be known jointly to the axes of rotation of the rotoid joints. The determination of the lengths of the operator's bones is relatively simple since radiographic images of the ankle can be studied to obtain fairly accurate estimates. However, the determination of the rotation axes is a challenge since the movement of the ankle depends on the size and orientation of the bones of the foot, and the shape of the articulated surfaces. Only current estimates of axes of articulation can be obtained by studying radiological images. More accurate estimates of the axes of articulation are desired to study ankle movement and such estimates are made possible by the data collected with the exoskeleton. With good estimates of bone lengths, rotational axes of the roto joints of the human ankle can be determined by instructing the operator to perform free RoM motions and collecting positional data of extensible links. (7) and preferably three rotation sensors placed on the hinge element (5). When data is available, the forward kinematics of the 3UPS configuration level is resolved for the configurations of the mobile platform (2) at each instant. Once the foot configurations are recorded, the inverse kinematics of the configuration level of the two-link RR manipulator with unknown rotoid axes (representing the human ankle) is resolved for the axes of the rotoid joints and the amount of rotation. around these axes. Given the forward and reverse kinematics of the configuration and motion level of the coupled 3UPS-RR system (the exoskeleton coupled to the human ankle) and the dynamic properties of the exoskeleton device (1) only, a robust position controller with a reaction torque observer can be implemented to characterize the dynamic properties of the ankle. In particular, by using a robust position controller, the exoskeleton device (1) can control the dowel on a desired trajectory, while the disturbance forces due to the unknown dynamics of the dowel can be estimated during this movement. When implementing the controller, the forces due to the known dynamics of the exoskeleton device (1) are added to the system in a direct manner to ensure that the disturbance acting on the system is solely due to the unknown dynamics of the system. ankle. Under such control, the forces controlled by the controller must oppose the unmodelled dynamics of the ankle. Therefore, the actuator forces can be mapped to the hinge pairs at the ankle and assuming that all other disturbances are relatively small, these couples provide an estimate close to the actual hinge moments due to the dynamic range. ankle. The exoskeleton device (1) can deliver passive, active, assisted, and resistive modes of exercise. Virtual tunnels and force fields inside these tunnels can be implemented to allow healthy practice with assistance or resistance. Since the device (1) in the 3UPS configuration allows all possible movements of the ankle throughout its amplitude, it is possible to use the device (1) for clinical measurements. First, the device can be used to determine the range of motion of the patient. When the patient moves his ankle, the device can measure and log the time history of this movement (the trajectory). Given the measured time history of the movements, it is possible to determine the speed with which the patient completes a motion, the amount of error involved with respect to a reference trajectory and the manner in which these movements are regular / intermittent. . Since the kinematics of the device (1) is known, it is also possible to map the measured configuration changes with respect to rotations of the ankle joint. This ability makes it possible to measure the orientation, the speed and the regularity of the movements of the ankle joint. The coordination and the synergies of the movements of the joint can also be detected from these measurements. As explained above, by using a robust position controller and controlling an exoskeleton device (1) to draw a desired path, the disturbance forces due to the unknown dynamics of the ankle can be estimated during this motion. These forces can also be mapped to ankle joint torques using ankle kinematics. This measurement technique can be used to determine the maximum hinge moments that the patient can exert depending on the impedance and tone of the patient's ankle, in any ankle configuration. In particular, if the gains of the robust position controller are determined to remain at a reference configuration, and the patient is called upon to apply maximum torque on his ankle joints, then the disturbance forces acting on the controller can be mapped. relative to the articulation torques to estimate the couples of the human ankle joint around the appropriate axes. Finally, according to a pre-specified reference path for the robust position controller, articulation torques can be estimated at each instant and the relationship between articulation rotation and articulation torques can be used to estimate impedance and / or tonicity of the ankle.

In another embodiment of the invention, the non-grounded, portable and reconfigurable measurement and therapy exoskeleton device for ankle therapy can be combined with virtual reality games. The description of the invention is purely exemplary and thus, variants which do not depart from the essence of the invention should be provided as being within the scope of the invention. Such variations should not be considered as a departure from the spirit and scope of the invention.

REFERENCES: [1] H. Tropp and H. Alaranta, Sport Injuries: Basic Principles of Prevention and Care, Proprioception and Coordination Training in Injury Prevention. Oxford, 1993. [2] D. Hung, M. Kennedy, A. Rowland, J. D. Purdy, and M. Yampolsky, "Ankle Rehabilitation: Evidence-Based Approach," Vanderbilt Rehabilitation Services. [3] J. Yoon, J. Ryu, and K. Lim, "A novel reconfigurable ankle robotic rehabilitation for 10 various exercise modes," Journal of Robotic Systems (Currently Journal of Field Robotics), vol. 22, no. 1, pp. 15-33, 2006. [4] R. Ekkelenkamp, P. Veltink, S. Stramigioli, and H van der Kooij, "Evaluation of a virtual model control for the selective support of functions using an exoskeleton," Rehabilitation Robotics, 2007. ICORR2007. IEEE 10th International Conference on, pp 693699, June 2007 [5] M. Girone, G. Burdea, and M. Bouzit, "The Rutgers Ankle Orthopedic Rehabilitation Interface," in Proceedings of the ASME Haptics Symposium, vol. 67, 1999, pp. 305-312. [6] M. Girone, G. Burdea, and M. Bouzit, V. Popescu, and J. Deutsch, "Orthopedic Rehabilitation Using the Rutgers Ankle Interface," in Proceedings of Virtual Reality Meets Medicine 2000, pp. 89-95. [7] JE Deutsch, J. Latonio, G. Burdea, and R. Boian, "Rehabilitation of Musculoskeletal Injuries Using the Rutgers ankle haptic interface: Three cases reports," in Proceedings of Eurohaptics 2001, July 1-4 2001, pp . 93-98 [8] J. E. Deutsch, J. Latonio, G.C. Burdea, and R. Boian, "Post-stroke rehabilitation with the 30 Rutgers ankle system: A case study," Presence: Teleoper. Virtual Environ., Vol. 10, no. 4, pp. 4161,130, 2001. [9] M. Girone, G. Burdea, M. Bouzit, V. Popescu, and J. E. Deutsch, "A Stewart platformbased system for ankle telerehabilitation," Autonomous Robots, vol. 10, no. 2, pp. 203-212, 2001. [10] RF Boian, M. Bouzit, GC BURDEA, J. Lewis, and JE Deutsch, "Dual Stewart platform mobility simulator," in Proceedings of the ICORR 2005, 9th International Conference on Rehabilitation Robotics, 2005 , pp. 550-555. [11] J. S. Dai, T. Zhao, and C. Nester, "Sprained ankle physiotherapy based mechanism synthesis and stiffness analysis of a robotic rehabilitation device." Auton. Robots, vol. 16, no. 2, pp. 207-218, 2004. [12] A. Agrawal, S. Banala, S. Agrawal, and S. Binder-Macleod, "Design of a two degree-offer of ankle-foot orthosis for robotic rehabilitation," Rehabilitation Robotics, 2005. ICORR 2005. 9th International Conference on, pp. 41-44, June-1 July 2005 [13] A. Roy, Krebs H., Patterson S., Judkins T., Khanna I., Forrester L., Macko R., Hogan N., "Measurement of human ankle. stiffness using the Anklebot, "Rehabilitation Robotics, 2007. ICORR 2007. IEEE 10th International Conference on, pp. 356-363, June 20, 2007. [14] CE Syrseloudis, IZ Emiris, CN Maganaris, and TE Lilas, "Design framework for a simple robotic ankle evaluation and rehabilitation device," Engineering in Medicine and Biology Society, 2008. EMBS 2008. 30th Annual International Conference of the IEEE, pp. 4310-4313, AUG. 2008. [15] J. Yoon and J. Ryu, "A new family of hybrid 4-DoF parallel mechanisms with two platforms and its application to a footpad device," Journal of Robotic Systems, vol. 22, no. 5, pp. 287-298, 2005. 30 [16] ---, "A novel reconfigurable ankle / foot robotic rehabilitation," Robotics and Automation, 2005. ICRA 2005. Proceedings of the 2005 IEEE International Conference on, pp. 22902295, April 2005.

Claims (10)

REVENDICATIONS1. Measuring and therapy exoskeleton device (1), portable and reconfigurable. for ankle, which can support two different types of exercises, that is, RoM / reinforcement exercises and balance / proprioception exercises independently of each other, including: a basic platform (3 ) which faces the operator's leg, a mobile platform (2) facing the operator's foot, a connecting element (4) which connects the base platform (3) and the mobile platform (2) ), a hinge member (5) which connects the connecting member (4) to the base platform (3). 2. Device according to claim 1, characterized in that the hinge element is a reconfigurable hinge which, in an unlocked position, can rotate freely about a first axis (A) and a second axis (B ), wherein the first axis (A) is tangential to the base platform (3) and the second axis (B) is perpendicular to the base platform (3). 3. Device according to claim 2, characterized in that, in an unlocked position of the reconfigurable joint, two rotoid joints in series, namely an upper articulation of the ankle and an astragalocalcanean articulation, function as a universal joint rotating around said first and second axes. Anchor measurement and therapy exoskeleton device according to claim 2, characterized in that, when the second axis (B) is locked, the reconfigurable joint is constrained to function as a rotoid joint, which is free of turn only around the first axis (A). - 30 5. Device according to any one of the preceding claims, characterized in that the connecting element (4) comprises a drive unit (6) and a movable element (7) .SR 54396 TM 14 An exoskeleton device according to any one of the preceding claims, further comprising a control unit and at least two sensors. 7. Device according to any one of the preceding claims, further comprising two sensors, one of the sensors measuring the length of the connecting element (4), the other sensor measuring the amount of axial rotation of the element. hinge (5), and a control unit which processes the measured data. Apparatus according to any one of the preceding claims, further comprising a robust position controller with torque monitors. 9. Use of a device according to any one of the preceding claims for carrying out clinical measurements. 15 10. Use according to the preceding claim, characterized in that the device measures the configuration of the joint, the speed of movement, the trajectory, the error of trajectory, the regularity of movement, the range of motion, the coordination and the synergies, maximum articulation torque, articulation torque while tracing any trajectory, tonicity and impedance of the ankle. 20