CZ2021495A3 - A movement subsystem and a robotic system designed to treat movement disorders - Google Patents

Abstract

A passive end-effector robotic system without motor drives, intended for the treatment of arm mobility disorders, comprising one of the movement subsystems (1A, 1B) containing four movably connected parallelograms, each parallelogram containing either parallel connecting rods ending in ball studs, or parallel telescopic gimbal rods ended with gimbal couplings. Each connecting or cardan rod is common to two adjacent parallelograms and ball joints, or cardan couplings are mounted on a pair of plates arranged parallel to the plane. For the anti-gravity relief of the motion subsystem (1A, 1B), there are between the first of the pair of plates and the two lower adjacent connecting ones, respectively. two springs held by gimbal rods. A grip for the treated arm is arranged on the second of the pair of plates, which protrudes outside the four movably connected parallelograms.

Description

Movement subsystem and robotic system designed to treat movement disorders

Field of technology

The present invention relates to movement subsystems and a robotic system containing a movement subsystem implemented using four interconnected parallelograms, while the robotic system further includes a camera located outside the movement subsystem further from the patient's upper limb (arm), and a signal point light source located on the movement subsystem closer to the patient's hand and indicating the position of the distal part of the upper limb.

Current state of the art

Rehabilitation robots are intended for the re-education of the movement of the patient's limbs, which are affected by diseases that lose their momentum. They are based on the use of biological feedback, biofeedback, usually visual, where the patient, whose affected limb is attached to the robot's effector, is supposed to follow the desired movement trajectory or perform a specified movement task. The rehabilitation robot uses sensors to monitor the result of the patient's efforts, by monitoring the immediate position of the distal part of the limb (end-effector type robot) or the position in all decisive joints (exoskeleton type robot), possibly also by measuring the applied muscle force. The control unit, which is connected to the sensors built into the movement mechanism of the robot, evaluates the success of the patient's efforts, and in case of failure, the robot with an active drive gently and carefully takes over the required movement, but only for a partial, usually short section of the required trajectory, after which it again provides chance for the patient. There are also robots with a passive solution, which do not include a drive, so that all movement of the limb is only a result of the free effort of the patient and his residual muscle strength. The process of moving a limb along a desired trajectory or the process of performing a desired movement task is repeated over and over again, so that the patient gets the opportunity to create new memory traces and/or new neural connections after many repetitions of the desired movement. The creation of new memory traces and/or new neural connections is a consequence of the neuroplasticity of the central nervous system. In this way, the patient learns again, i.e. re-educates the lost momentum of his affected limb. In this rehabilitation procedure, it is therefore very important to ensure the movement of the patient's limb by a cooperating rehabilitation robot. Rehabilitation robots also include a processor unit that receives data from sensors. The processor unit includes a memory in which data about the desired movement of the effector is stored. The processor unit compares the data received from the sensors with the data stored in the memory, representing the ideal desired trajectory of the movement of the limb. The result of the comparison provides information about improving the mobility of the limb, which is valuable diagnostically. In the case of an active drive, the result of the data comparison is also information for controlling the drives ensuring the desired movement of the limb, which the patient is not yet capable of.

Patent application EP 0016094 A1 describes a programmable exercise machine. The exercise machine consists of two arms. The arms are arranged in series and are connected to each other by a rotary joint. The swivel joint is equipped with a separate drive that rotates the swivel joint. The user moves the effector located on the farthest arm. The movement of the effector is influenced, on the one hand, by the user's limb and on the other hand by a separate drive, and is controlled by a feedback system. The feedback system ensures that the effector moves along a pre-specified trajectory through the force exerted by the user, while simultaneously providing resistive forces that vary arbitrarily in position, velocity, time, or force exerted by the user.

The limb rehabilitation device described in Chinese patent application CN 105581891 A includes a rotating mechanism, a telescopic mechanism and a movable arm. The rotary mechanism includes a rotary drive device and a rotary arm connected to the rotary drive device. The swing arm rotates around a fixed shaft using a rotary drive. One end of the swing arm that is near the fixed shaft is called the fixed end. The other end is called

- 1 CZ 2021 - 495 A3 swivel end. Two swivel joints are arranged on the swivel arm. The pivot joint located near the fixed end is referred to as the first pivot joint and the pivot joint located at the opposite end of the pivot arm is referred to as the second pivot joint. One end of the pivot arm is rigidly connected to the effector, while the other end is connected to the pivot arm in a second pivot joint. The telescoping mechanism includes a telescoping drive and a telescoping arm coupled to the telescoping drive.

Patent US 9403056 B2 describes a rehabilitation system that allows patients to improve coordination of forearm and hand movements. The rehabilitation system includes a multi-degree-of-freedom effector equipped with means for providing precisely modulated resistive forces and precisely modulated driving forces. The rehabilitation system also includes a display device for simulating virtual reality, through which the desired trajectory of the effector movement is displayed. The sensing device of the rehabilitation system enables the sensing of force, load, torque, angular displacement, angular velocity, displacement and/or position of the effector. The control unit of the rehabilitation system includes a memory for storing data on the movement of the effector and a processor for calculating resistance forces and movement forces of the effector. The means for providing precisely modulated resistance forces comprises a hydraulic circuit with a pump which is connected to the control unit.

European patent application EP 2926724 A1 deals with a method for assessing the movement of a point related to the distal part of a limb in a predetermined 3D space. This application includes a complex network of sensors adapted to detect the position of the limb in 3D space in relation to the joints.

Chinese patent application CN 105662783 A presents a solution for an exoskeleton-type rehabilitation therapy robot of the upper limb, where movement in each of the arm joints is monitored by sensors and controlled by motors.

US patent application US 2014172166 A1 presents a solution based on mirror therapy intended for the treatment of hemiparesis, where signals from a healthy arm are transmitted to a robot moving an arm with impaired mobility, while the patient follows the movements of both limbs.

The Swiss company Hocoma launched a series of sophisticated rehabilitation therapy robots on the market and for use in the healthcare sector, of which the Armeo Spring type (without active drives) and the Armeo Power type (with drives) are intended for the purpose of rehabilitation of the mobility of the upper limb. Both types of these rehabilitation therapy robots are exoskeleton solutions. The Armeo Spring robot uses a simple parallelogram for the construction of the movement subsystem, which ensures the guidance of the elbow part of the arm.

Similar motion subsystems and robotic systems for the treatment of movement disorders are known from US 5466213 A, CN 109568082 A and WO 2015041618 A2, and from HOWARD, Ian S., et al. (A modular planar robotic manipulandum with end-point torque control. Journal of Neuroscience Methods, 2009, Vol. 181, No. 2, p. 199-211, ISSN 0165-0270), and RAHMAN, Mohammad H., et al. (Tele-operation of a robotic exoskeleton for rehabilitation and passive arm movement assistance. In: Proceedings of the 2011 IEEE International Conference of Robotics and Biomimetics, 7.12.2011 - 11.12.2011, Phuket, Thailand).

Disadvantages of devices that are known from the prior art can be seen in the fact that the positioning devices of rehabilitation robots and their arms usually represent complex kinematic arrangements and the robots are characterized by complex constructions of the movement subsystem. Moving parts are heavily loaded and strained and usually have considerable weight. A sensor system requires multiple sensors, is complex, and converting signals from sensors to position data is also challenging.

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The essence of the invention

The invention aims to design a robotic rehabilitation system of a passive type (without active drives), which provides a simple solution to the movement subsystem and minimizes the difficulty of sensing the position of the distal part of the upper limb for this subsystem.

A simple solution of the movement subsystem is ensured by means of a kinematic arrangement created by a movable connection of four parallelograms at their vertices by means of connecting rods according to the first embodiment or telescopic gimbal rods according to the second embodiment. Movable connections in the vertices of the parallelograms are formed either by ball pins according to the first embodiment, or by cardan couplings (cardan joints) according to the second embodiment. When using ball pins, it is necessary to introduce a central stabilizing telescopically extendable element, which is not necessary when using cardan couplings. Both alternative designs ensure the low weight of the moving parts of the motion subsystem, its simple production and assembly, as well as the smooth and flexible movement of the arms of the positioning device, while at the same time being able to reach a sufficiently large working space. Since the solution is passive - without active drives, it is necessary to provide anti-gravity dynamic support of the limb using a pair of springs.

The above-mentioned objective is achieved in that, in the movement subsystem according to the first embodiment, the ball pins are fixedly mounted to the corners of one and the other square or rectangular plate by means of an exemplary screw connection through their hole, in such a way that the corner of the plate is beveled at an angle of 45° and the axis of the screw connection runs parallel to the surface of the plate, which - to allow this assembly - must have a sufficient thickness. A gimbal coupling is fixed to the center of each of the two plates between the ball pins, between which a connecting telescopic cardan rod is attached, which creates a parallel arrangement of the plates, reduces the number of degrees of freedom of the ball pins and, thanks to the telescopic design, all minor deviations in the movement of the connecting pins can be balanced rods in ball joints. All four ball studs on both parallel plates are connected by connecting rods, e.g. threaded rods. One of the plates (the first plate) is intended for fixing to the stand of the robotic system, while the other plate is freely movable.

In the movement subsystem according to the second embodiment with gimbal rods, the gimbal couplings are, for example, mounted on both plates directly in their surface perpendicular to it, preferably in a square or rectangle. These gimbal couplings are directly connected to each other by telescopic gimbal rods and thus form a gimbal connection, without the need for any additional stabilizing element reducing an excessively high degree of freedom. One of the plates (the third plate) is designed to be fixed to the stand of the robotic system, while the fourth plate is freely movable.

For the reasons of anti-gravity dynamic balancing of the self-weight of the movement subsystem according to the solution with ball joints or the solution with gimbal joints, as well as for the reasons of balancing the weight of the limb, two springs of suitable parameters are immovably fixed between the first/third plate and the two adjacent connecting/gimbal rods, ensuring the necessary antigravity dynamic support of the treated limb, which is connected to the robot effector (grip) located on a plate further from the robot stand. The non-sliding attachment of the springs to two adjacent connecting/gimbal rods can be replaced with a sliding attachment for the possibility of individualizing the anti-gravity dynamic balance for different patients.

Sensing the position of the end part of the moving limb is ensured by a camera sensing the position of a point light source, which is located near the end (distal) part of the limb, or near the effector (grip) directly on the movement subsystem. The camera is placed on the stand at a suitable distance allowing it to capture the entire workspace of the robot. The signal from the camera informing about the position of the point light source (corresponding to the position of the distal part of the limb) in the projection onto the plane perpendicular to the axis of the scanning camera (xy plane) is led to the microprocessor control unit, where it is compared with the immediate required position. A file of all instant

- 3 CZ 2021 - 495 A3 of the desired positions is entered into the sparse unit and represents the desired trajectory along which the limb should move. The required (pre-programmed, therapeutically suitable) and the actually realized trajectory are displayed on the monitor, and at the same time the difference between these trajectories is evaluated, which is an indicator of the success of the ongoing therapy with the rehabilitation robot, while the change in the impairment of arm mobility is calculated and quantified after repeated realization of the desired trajectory.

Clarification of drawings

The invention will be further explained with the help of the drawings, where:

• Fig. 1 shows the construction of the motion subsystem according to the first embodiment with ball pins;

• Fig. 2 shows the construction of the motion subsystem according to the second embodiment with cardan couplings;

• Fig. 3 shows separately the connection of cardan couplings from the second embodiment;

• Fig. 4a shows the overall sheathed arrangement of the rehabilitation robotic system;

• a 3D view of the robotic system is shown in Fig. 4b;

• Fig. 4c shows a side view of the robotic system;

• in Fig. 5 is a block diagram of the connection between the control microprocessor unit, the camera, the point light source and the monitor; and • Fig. 6 approximates the projection of the position of the light point source onto the xy plane perpendicular to the camera axis.

Examples of implementation of the invention

The invention will be explained in the following description with reference to the relevant drawings. The solution according to this invention represents the arrangement of a rehabilitation worker system in a passive design of the end-effector type.

The motion system 1A or 1B is shown in Fig. 4 together with the camera 17 and the light point source 20 placed on the neck 15, on which the monitor 16 is also fixed, on which the desired pre-programmed trajectory is displayed by means of the control microprocessor unit 23 the patient's hand is supposed to move, as well as the actual trajectory along which the distal part of the patient's arm actually moves.

An example of the movement subsystem 1A according to the first embodiment with ball pins 3 is shown in Fig. 1. This embodiment includes a first plate 4 and a second plate 5, in the chamfered corners of which ball pins 3 are arranged, attached by means of screw connections 13 through the eyes of the ball pins 3 to the first and the other plates 4 and 5 so that the axis of the screw connection 13 is parallel to the surfaces of these plates 4 and 5 and is directed to their center. The first and second plates 4 and 5 are connected to each other by four connecting rods 9 and by a connecting telescopic gimbal rod 12, which is terminated by gimbal joints 12a fixed between ball pins 3 on the first plate 4 and the second plate 5. The first plate 4 is made of from the patient's point of view is located further away and is intended for fixing 18 on the stand 14, while the second plate 5 is located closer to the patient and therefore the grip 8 itself (effector) for the patient's rehabilitated arm is fixed on it. On two lower, adjacent ones

- 4 CZ 2021 - 495 A3 of the connecting rods 9, in a place closer to the grip 8 (effector), sleeves 9a are arranged and in them the first ends of a pair of springs 11 are immovably fixed, while their second ends are immovably fixed on the first plate 4. Fixing of the first ends the pair of springs 11 in the sleeves 9a can also be movable relative to the connecting rods 9 (not shown in Fig. 1) for the possibility of individual anti-gravity dynamic balancing of different weights of the upper limbs of the patients.

Another example of the movement subsystem 1B according to the second embodiment with cardan connection 10c is shown in Fig. 2. The arrangement here is similar to the solution shown in Fig. 1, but instead of ball pins 3, cardan couplings 2 are used here. These are fixed directly by screw connections 13 to the corners of the third and fourth plates 6 and 7, and are oriented perpendicular to the surfaces of the third and fourth plates 6 and 7. Furthermore, the corresponding gimbal couplings 2 are connected to each other by telescopic gimbal rods 10 and thus form a gimbal connection 10c without the need for additional elements connecting the third and fourth plates 6 and 7 arranged in such a plan-parallel manner. The third plate 6 is located farther from the patient's point of view and is intended for fastening 18 to the stand 14, while the fourth plate 7 is located closer to the patient and therefore the grip itself 8 (effector ) for the patient's rehabilitated arm. Sleeves 10a are arranged on two lower, adjacent gimbal rods 10 in a place closer to the grip 8 (effector) and in them the first ends of a pair of springs 11 are immovably fixed, while their second ends are immovably fixed on the third plate 6. Fixing of the first ends of the pair the springs 11 in the sleeves 10a can also be movable with respect to the cardan rods 10 (not shown in Fig. 2) for the possibility of individual anti-gravity dynamic balancing of different weights of the upper limbs of patients.

An illustration of the gimbal joint 10c itself, which is formed by a gimbal rod 10 equipped on both sides with gimbal joints 2, is shown in Fig. 3. This gimbal joint is structurally identical to the gimbal joint of gimbal joints 12a and the connecting telescopic gimbal rod 12 in the first embodiment.

Figure 4a shows the complete assembly of the robotic system, which includes a stand 14 covered by a casing 21, where the fixing 18 of the first/third plate 4, 6 of the movement subsystem 1A, 1B on the stand 14 is decisive. Furthermore, Figure 4a shows the location of the camera 17 on neck 15 of the stand 14, which ensures that the field of view of the camera 17 covers the entire workspace of the robot. A monitor 16 is arranged at the top of the neck 15, on which the desired trajectory of the movement of the limb as well as the gradually achieved actual trajectory are displayed. The monitor 16 also displays the evaluated and quantified difference between the desired and actual trajectory, which has a motivational effect for the patient and a diagnostic value for the doctor. The movement subsystem 1B itself is covered by a flexible cover 22. At the end of the movement subsystem 1A, 1B, closer to the patient, a holder 19 with a point light source 20 is located in close proximity to the effector 8.

Figure 5 shows the connection of signals between the electronic, digitally working components of the control system with which the worker system is equipped. In this case, the control microprocessor unit 23 is connected to the camera 17, which detects the point light source 20, and further, the control microprocessor unit 23 is signal connected to the monitor 16. Fig. 6 then approximates the projection of the position of the light point source 20 to the xy plane perpendicular to the axis of the camera 17.

The control microprocessor unit 23 is connected to the signal from the camera 17 sensing the projection of the position of the light point source 20 in a plane perpendicular to the axis of the camera 17.

The control microprocessor unit 23 then provides information about the immediate required (pre-programmed) and actual position of the light point source 20, and at the same time the control microprocessor unit 23 processes information about the differences in these positions, thus providing information about the patient's ability to move the limb along the desired trajectory. The mentioned solution predetermines a robotic system for feedback-controlled re-education of the movement of the upper limb affected by its mobility disorder.

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Industrial applicability

The robotic system according to the present invention, using a movable connection of four parallelograms 5 of the movement subsystem according to the present invention and a camera sensing a light point located near the robot effector, is intended for use in medicine as a rehabilitation therapy robot for the re-education of arm mobility disorders.

Claims (6)

1. A robotic system of the passive end-effector type without motor drives, intended for the treatment of arm mobility disorders, characterized in that it contains a first movement subsystem (1A) or a second movement subsystem (1B), wherein the first movement subsystem (1A) contains four movably connected parallelograms, of which each parallelogram contains parallel connecting rods (9) terminated by ball pins (3), while each connecting rod (9) is common to two adjacent parallelograms and the ball pins (3) are fixed to the first and second plates arranged parallel to each other (4, 5), while in the space between the four parallel connecting rods (9) and parallel to them, a connecting telescopic gimbal rod (12) terminated with gimbal joints (12a) is attached to both plates (4, 5), while on the second plate ( 5) a grip (8) for the treated arm is arranged, which protrudes outside the four parallelograms movably connected to each other, and for the anti-gravity relief of the first motion subsystem (1A), two springs are clamped between the first plate (4) and the two lower adjacent connecting rods (9) (11), while the first plate (4) is fixed in the robotic system and the second plate (5) is freely movable, while the second motion subsystem (1B) contains four movably connected parallelograms, each of which contains parallel telescopic gimbal rods ( 10) ended with gimbal joints (2), while each telescopic gimbal rod (10) is common to two adjacent parallelograms and the gimbal joints (2) are fixed on the planparallel arranged third and fourth plates (6, 7), while on the fourth plate (7 ) a grip (8) for the treated arm is arranged, which protrudes outside the four movably connected parallelograms, and for the anti-gravity relief of the second motion subsystem (1B) two springs are clamped between the third plate (6) and the two lower adjacent telescopic gimbal rods (10) (11), while the third plate (6) is fixed in the robotic system and the fourth plate (7) is freely movable. 2. A robotic system according to claim 1, characterized in that the ball pins (3) of the first movement subsystem (1A) are arranged in a square on the plates (4, 5). 3. A robotic system according to claim 1 or 2, characterized in that a light point source (20) is arranged on the second plate (5) of the first movement subsystem (1A) near the grip (8). 4. Robotic system according to claim 1, characterized in that the gimbal couplings (2) of the second movement subsystem (1B) are arranged in a square on the plates (6, 7). 5. A robotic system according to claim 1 or 4, characterized in that a light point source (20) is arranged on the fourth plate (7) of the second motion subsystem (1B) near the grip (8). 6. A robotic system according to any one of the preceding claims, characterized in that it further includes a control microprocessor unit (23) which is connected to a camera (17) for sensing the position of the light point source (20) and to a monitor (16) for displaying the movement trajectory light point source (20).