MECHANISM AND METHOD FOR PERFORMING FORCE IMPULSES IN TENDON SYSTEMS

Abstract

A mechanism and method for the implementation of assistive or resistive forces or force impulses in tendon systems during walking on a treadmill, which enables the implementation of the established method of training the maintenance of dynamic balance during standing or walking. The mechanism includes a source of rotary mechanical energy, which is mechanically connected to the mechanical axis via an axial coupling. The mechanical axis is supported in two places by bearings, and on the mechanical axis, a winding reel is attached in a fixed manner through the central roller, and in which between the sides of the winding reel eccentrically with respect to the axis of rotation of the reel, a tensioning cylinder is installed in a fixed manner. The central roller and the tension roller of the winding reel are concentrically embraced by the cylinders, each of which can rotate freely around its own roller.

Claims

1. A mechanism for applying assistive or resistive forces or force impulses to a body, the mechanism comprising: a tension element connectable with its proximal end to a body and with its distal end to a fixed point; and a deflecting element adjustable between a location or orientation, in which the tension element is free of an impingement and a location or orientation, in which the tension element is deflected to cause a force or a force impulse to the body.

2. The mechanism according to claim 1, wherein the deflecting device is formed as a rotating body and the tension element is crossing an axis of rotation.

3. The mechanism according to claim 2, wherein the rotating body is formed as a winding reel.

4. The mechanism according to claim 3, wherein the tension element is guided radially through an opening of the winding reel.

5. The mechanism according to claim 3, wherein the winding reel comprises a central roller and at least one side plate extending radially over the central roller, wherein, eccentrically with respect to the axis of rotation of the winding reel, a tensioning roller is installed in a fixed manner on a side plate, and wherein through a gap between the central roller and the tensioning roller passes and moves freely in the tangential direction relative to the central roller the tension element, when the winding reel is in the location or orientation, in which the tension element is free of an impingement.

6. The mechanism according to claim 5, wherein the central roller and the tensioning roller of the winding reel are concentrically embraced by cylinders, each of which being adapted to rotate freely around its own roller).

7. The mechanism according to claim 5, wherein further comprising a source of rotary mechanical energy, which is mechanically connected to a mechanical axis, and wherein the mechanical axis is supported by at least one bearing, and on the mechanical axis the winding reel is attached in a fixed manner through the central roller.

8. The mechanism according to claim 1, wherein the tension element is formed by a rigid tendon, which is attached at the proximal end to a cuff, which embraces the selected segment of the human body, and at the distal end is with a connecting joint connected to an elastic element that provides tension to the tendon and which is clamped at the opposite end to the fixed point directly or indirectly via a pulley.

9. The mechanism according to claim 1, wherein a tensioning of the tension element is performed such that the tension element is directly connected either to an elastic element of constant stiffness or a weight is suspended over it via a pulley.

10. The mechanism according to claim 1, wherein the tension element is fixed with its distal end on a storage reel as the fixed point, on which is acting a spring to provide a tensioning force.

11. The mechanism according to claim 10, wherein the storage reel is supported on a storage reel-axis, on which the spring in the embodiment of a worm spring or torque spring acts.

12. The mechanism according to claim 11, wherein on the storage reel-axis, a decoder is arranged to detect a movement and/or orientation of the storage reel.

13. The mechanism according to claim 1, wherein a treadmill is assigned to carry the body.

14. The mechanism according to claim 8, wherein the tendon is fed through the gap between the central roller and the tension roller of the winding reel, wherein, when the winding reel turns, the tendon is clamped against the tension roller or the tendon is fed radially through the axis of rotation of the winding reel, wherein the tendon is clamped against the central roller when the winding reel turns, and wherein, in intervals between, by applying force, the tendon moves freely through the opening in the winding reel.

15. The mechanism according to claim 5, wherein the source of rotational energy is a device capable of generating rotational mechanical energy on the mechanical axis, via an electric motor or a servo motor, and wherein the electric motor or the servo motor is used together with a transmission for power transmission.

16. The mechanism according to claim 15, wherein that the source of rotational energy comprises a flywheel, which is connected to the mechanical axis by an electromagnetic clutch, and to which the electric motor or the servomotor either directly or via a belt/chain supplies rotational mechanical energy, which is transferred to the mechanical axis when the electromagnetic clutch is activated.

17. The mechanism according to claim 1, wherein a sensor is provided to monitor the periodic displacement of the tension element, and wherein a control element is provided to use the changes in the direction of the movement of the tension element for triggering the application of force impulse.

18. The mechanism according to claim 17, wherein the sensor is an optical encoder attached to the pulley.

19. The mechanism according to claim 17, wherein a plurality of sensors are used to improve reliability and robustness of triggering the application of force impulse.

20. A method of training the maintenance of dynamic balance during standing or walking using assistive or resistive forces or force impulses, the method comprising: performing the training on the mechanism according to claim 1 for performing assistive or resistive forces or force impulses in tendon systems during walking on a treadmill according; and creating, during an application of force, a pull of the body segment by winding the tendon on the winding reel, and in the intervals when the force is not applied, the tendon follows the movement of the human segment according to the principle of transparent interaction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0015] FIG. 1 is a schematic representation of the structural design of the tendon length modulation mechanism in concrete use,

[0016] FIGS. 2a to 2e show schematic representations of the principle of operation by application of assistive or resistive forces or force impulses by the tendon winding,

[0017] FIGS. 3a to 3d show schematic representations of the principle of operation by the mechanical separation of the tendon from the source of force in the intervals between application of assistive or resistive forces or force impulses,

[0018] FIGS. 4a to 4d show schematic representations of the possible implementations of the device,

[0019] FIGS. 5a to 5b show examples of the winding reel,

[0020] FIG. 6 is a schematic representation in which a tension element is fixed with its distal end on a storage reel, and

[0021] FIG. 7 shows a pelvis translation during walking shown as a trajectory in space and shown as projections in all three planes of movement.

DETAILED DESCRIPTION

[0022] FIG. 1 shows a schematic representation of the construction of the proposed mechanism for the implementation of assistive or resistive forces or force impulses on a selected body segment while standing or walking on a treadmill for tendon systems with a demonstration of concrete use.

[0023] The mechanism for applying assistive or resistive forces or force impulses to a body is characterized in that a tension element is connectable with its proximal end to the body and with its distal end to a fixed point 12. A deflecting element is provided and adjustable between a location or orientation, in which the tension element is free of an impingement, and a location or orientation, in which the tension element is deflected to cause a force or a force impulse to the body.

[0024] In the example shown in the figures, the deflecting device is formed as a rotating body, namely, as a winding reel 5, whereby the tension element is crossing the axis 3 of rotation.

[0025] FIG. 5b shows an example, where the tension element is guided radially through a hole of the winding reel 5, whereas FIG. 5a and also FIG. 1 refers to an example, where the winding reel 5 is formed of a central roller 5 and at least one side plate 20 extending radially over the central roller 5. The embodiment shown in the FIG. 5a has two side plates 20. Eccentrically with respect to the axis 3 of rotation of the winding reel 5 a tensioning roller 5 is installed in a fixed manner on the side plates 20, whereby through the gap between the central roller 5 and the tension roller 5 passes and moves freely in the tangential direction relative to the central roller 5 the tension element, when the winding reel 5 is in the location or orientation, in which the tension element is free of an impingement. The examples in the FIGS. 1 to 4 show embodiments, where the central roller 5 and the tension roller 5 of the winding reel 5 are concentrically embraced by cylinders 6, 7, each of which can rotate freely around its own roller 5, 5.

[0026] Source 1 of rotational mechanical energy, e.g. electric rotary actuator, is mechanically connected to the mechanical axis 3 through the axis coupling 2, to which the rotary energy source 1 transfers the rotary mechanical energy to rotate it, when necessary. The source 1 of rotational mechanical energy is any device capable of generating rotational mechanical energy on the mechanical axis 3, e.g. an electric motor or a servo motor 15 (e.g. FIG. 4a) with or without a transmission 16 (e.g. FIG. 4b), which transfers the mechanical rotational energy to the mechanical axis 3 directly by means of a mechanical coupling or indirectly via a belt 19 (e.g. FIG. 4d) or an electromagnetic coupling. The mechanical axis 3 is supported by bearings 4, preferably in two places, and the winding reel 5 is fixed to it in such a way that the mechanical axis 3 passes through the central roller 5 of the winding reel 5. Between the sides of the winding reel 5, eccentrically with respect to the axis of rotation of the reel, there is the tension roller 5, which is displaced from the common axis of rotation of the winding reel 5 and the mechanical axis 3 so that the tendon 8 passes between the central roller 5 and the tension roller 5 and that it moves freely in the tangential direction with respect to the central roller 5, when the application of assistive or resistive forces or force impulses does not take place. The central roller 5 and the tension roller 5 of the winding reel 5 concentrically surround the cylinders 6 and 7 respectively, each of which can rotate freely around its own roller.

[0027] Rigid tendon 8, e.g. a rigid cord or braided wire is attached at one end to the attachment point on the cuff 14, which embraces the selected body segment of the user while walking on the treadmill 13. The attachment of the tendon 8 to the cuff 14 can also be realized with an intermediate elastic coupling of suitable stiffness. The opposite end of the rigid tendon 8 is routed through the gap between the central roller 5 and the tension roller 5 and is connected with a connecting joint 9, e.g. a mechanical or chemical joint by an elastic element 10 of weak stiffness, e.g. an elastic cord that stretches the tendon. The elastic element 10 is attached at the opposite end to the fixed point 12 directly or indirectly via the pulley 11. The tensioning of the rigid tendon 8 can also be carried out in such a way that instead of the elastic element 10, the rigid tendon 8 is directly connected either to an elastic element of constant stiffness or is a weight suspended on it via a pulley.

[0028] FIGS. 2 and 3 shows the principle of operation of the proposed mechanism. Depending on whether the proposed mechanism works in the phase of application of an assistive or a resistive force or force impulse, or in the intermediate intervals when it does not apply any forces, the proposed mechanism can demonstrate two principles of operation. FIG. 2 shows the principle of operation of the proposed mechanism in the phase of application of an assistive or resistive force or force impulse. At the beginning of the application of an assistive or resistive force or force impulse (FIG. 2a), the assembly of the tendon 8 and the elastic element 10 of weak stiffness is tensioned and passes through the gap between the central roller 5 and the tension roller 5, and the source 1 of rotary mechanical energy to the mechanical axis 3 begins to transmit rotational energy, due to which the winding reel 5 begins to rotate. When the winding reel 5 is turned, the tendon 8 is clamped against the tension roller 5 and begins wind on the winding reel 5 (FIG. 2b and FIG. 2c). As a result of winding, both ends of the tendon 8 (the proximal end which is attached to the user and the distal end which is connected to the elastic element) move towards the winding reel 5, which reflects in the pulling of the user in the direction of the tendon 8 towards the winding reel 5 with a force F1 and the pull of the elastic element 10 of weak stiffness towards the winding reel 5 with the force F2, due to which it stretches. The further transfer of rotational energy to the mechanical axis 3 increases the rotation of the winding reel 5 and the length of the tendon 8, which is wound on it from both sides, as a result of which the traction force of the user F1 and the stretching force of the elastic element F2 increase (FIG. 2d and FIG. 2e). During the winding of the tendon on the winding reel 5, the tendon 8 is clamped against the tension roller 5 at the same place all the time.

[0029] FIG. 3 shows the principle of operation of the proposed mechanism in the intermediate intervals when the application is not running. When the transfer of rotational energy to the mechanical axis 3 is discontinued, the tendon 8 is maximally wound on the winding reel 5 (FIG. 3a). Two forces act on it: i) when the user returns to stationary walking, he pulls the tendon 8 on the proximal side away from the winding reel 5 with the force F1, ii) since the tendon 8 is wound on the winding reel 5 also on the distal side, the elongation of the elastic element 10 is then maximal; as a result the elastic element 10 at the distal end of the tendon 8 creates a pull with a force F2 (FIG. 3a). Due to the torque of the two forces, the winding reel 5 automatically rotates in the opposite direction, so that the tendon 8 is completely unwound and mechanically separated from the winding reel 5, and the tendon 8 moves freely through the gap between the central roller 5 and the tension roller 5 of the winding reel 5 (FIG. 3b). The tension of the assembly of the tendon 8 and the elastic element 10 of weak stiffness is reduced to the level as was before the application of the assistive or resistive force or force impulse and, due to the weak stiffness, is small but sufficient so that the tendon 8 is tensioned all the time.

[0030] If the user moves in the direction of the tendon 8 away from the winding reel 5 (FIG. 3c), the tendon 8 moves freely through the gap between the central roller 5 and the tension roller 5 of the winding reel 5 in the direction of the user away from the reel 5. The length of the elastic element 10 of weak stiffness increases slightly, which slightly increases the force with which the tendon 8 and the elastic element 10 are tensioned, F1 and F2 respectively (F1=F2). But due to the weak stiffness of the elastic element 10, the tension remains small.

[0031] If the user moves in the direction of the tendon 8 towards the winding reel 5 (FIG. 3d), the tendon 8 moves freely through the gap between the central roller 5 and the tension roller 5 of the winding reel 5 in the direction towards the reel 5. The length of the elastic element 10 of weak stiffness is slightly reduced, as a result of which the force with which the tendon 8 and the elastic element 10 are tensioned is slightly reduced, but not so much that the tendon 8 would become loose.

[0032] FIG. 4 shows possible implementations of source 1 of rotational energy. The source 1 of rotational mechanical energy is any device capable of generating rotational mechanical energy on the mechanical axis 3, e.g. an electric motor or a servo motor with or without a transmission, which transfers the mechanical rotational energy to the mechanical axis 3 directly by means of a mechanical coupling or indirectly via a belt or an electromagnetic clutch.

[0033] In FIG. 4a, an electric motor or a servo motor 15 is used as a source 1 of rotational energy, which transfers rotational energy to the mechanical axis 3 via the axial coupling 2 when it is switched on. Such a direct transfer of energy from the engine to the mechanical axis 3 requires the use of high-torque motor drives if sufficient efficiency is to be achieved.

[0034] In order to increase the torque on the mechanical axis, a motor drive with a transmission 16 can be used as a source 1 of rotary mechanical energy (FIG. 4b).

[0035] In FIG. 4c and FIG. 4d, the flywheel 17the body that stores the rotational energyis used as the source 1 of rotational mechanical energy, which is connected to the mechanical axis by the electromagnetic clutch 18. When the clutch is activated, the rotational energy from the flywheel 17 is transferred to the mechanical axis 3. Here, an electric motor or servo motor 15 can be used to provide the rotational energy to the flywheel 17, which increases the rotational energy of the flywheel 17 either directly (FIG. 3c) or indirectly via the belt/chain 19 (FIG. 4d).

[0036] FIG. 5 shows the possible implementations of the winding reel 5. FIG. 5a shows the solution when the cylinders 6 and 7 are removed from the winding reel 5, which otherwise concentrically embrace the central cylinder 5 and the tension cylinder 5 of the winding reel 5. Omitting cylinders 6 and 7 improves the adhesion of the tendon 8 when it is clamped against the tension roller 5 during the application of an assistive or resistive force or force impulse, and at the same time slightly increases the friction between the tendon 8 and the winding reel 5 when the force is not applied and the tendon 8 only slides through the gap between the central 5 and the tension 5 roller.

[0037] In the second embodiment (FIG. 5b), the tendon 8 is guided radially through the axis of rotation of the winding reel 5. The tension roller 5 is unnecessary in this case, since upon application of an assistive or resistive force or force impulse, the winding reel 5 rotates and the tendon 8 is clamped against the central cylinder 5 of the winding reel 5. In the intervals between the applications of an assistive or resistive force or force impulse, the tendon 8 moves freely through the hole in the winding reel 5.

[0038] FIG. 6 refers to an example, where the tension element is fixed with its distal end on a storage reel 22 as the fixed point 12, on which is acting a spring 23 to provide a tensioning force, which is suited to ensure, that the tension element is taut. The storage reel 22 is supported on a storage reel-axis 24, on which the spring 23 in the embodiment of a worm spring or torque spring acts. Furthermore, on the storage reel-axis 24 a decoder 21 is arranged to detect the orientation of the storage reel 22. The storage reel-axis 24 is supported by at least one bearing 4.

[0039] It is to mention that in the drawing examples are shown with only one mechanism for performing force impulses on the walking human body, however, more than one mechanism can be used, especially also four mechanisms acting on the coupling for the connecting to the body like the cuff in four directions, e.g. right and left and forward and rearward. These directions can be tilted around the body axis of the human.

[0040] Furthermore, the use of the decoder 21 can also improve the application of the force to the body, since the decoder 21 monitors the turning of the storage reel 22, which is directly related to the phase of each step of the walking person. This gait detection analyses for example the movement of the hip.

[0041] A sensor is provided to monitor the periodic displacement of the tension element whereby a control element is provided to use the changes in the direction of the movement of the tension element for triggering the application of force impulse. The sensor can be optical encoder attached to the pulley 11. A plurality of sensors can be used to improve reliability and robustness of triggering the application of force impulse.

[0042] During walking on a treadmill or overground all body segments undergo cyclical movement. The pelvis for example is displaced and rotates in all directions. By monitoring the length of the tensional element attached to the side (or any other point) of the pelvis a characteristic and periodic signal is obtained a shown in FIG. 7. By detecting the change of direction of the movement of the pelvis one can extract distinct gait events during the gait cycle. For example, the peak lateral displacement of the pelvis occurs in the middle of the gait cycle. It is straight forward to estimate other events such as heel strike or toe-off from the duration of gait cycle as determined from consecutive peak displacement.

[0043] Similar is the situation if the tensional element is attached to the knee or the ankle of a leg. Also, in this case a periodic signal, similar to those shown in FIG. 7 is obtained and by detecting the change of direction of tensional element (identifications of peaks of movement) heel strike event (direction of tensional element movement changes from forward to backward) is detected or toe-off event (direction of tensional element movement changes from backward to forward) is detected.

[0044] When the tensional element or tendon is attached to the left side of the body (left side of the pelvis or the knee or the ankle of the left leg) left heel strike, left toe-off are determined. The opposite holds for the right side.

[0045] These distinct gait events can then be used to trigger and generate a perturbing force impulse.

[0046] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.