A rehabilitation robot for restoring fine motor skills of the hand

Abstract

Use: medical equipment, namely rehabilitation robots and exoskeletons for passive development of the joints of the hand and fingers using the continuous passive mobilization method (CPM therapy). The objective of the utility model is to expand the functional capabilities of the robot. The essence of the utility model: a rehabilitation robot comprises a body 1 configured to be attached to a patient's forearm using a system of adjustable belts 2. Inside the body 1, there is a control unit (not shown in the figures) and a battery (not shown in the figures). A first electromechanical drive 3 intended for developing the hand is fixed in the body 1. The output shaft of the first drive 3 is kinematically connected to a palm support 5. The palm support 5 is configured to fix the patient's palm and ensure rotation of the hand in the wrist joint. A second independent electromechanical drive 4 intended for developing the fingers is mounted on the palm support 5.The output shaft of the second drive 4 is kinematically connected to the system of rigid rods 6. Each rigid rod 6 has a fingertip 7 at its free end for fixation on the patient's finger. Rigid rods 6 ensure the transmission of both pushing and pulling forces from the drive 4 to the fingers. The first absolute encoder 8 is mounted on the shaft of the first drive 3. The second absolute encoder 9 is mounted on the shaft of the second drive 4. The outputs of encoders 8 and 9 are connected to the inputs of the control unit. Positive effect: the proposed device ensures safe passive restoration of fine motor skills in patients with neurological and traumatic injuries of the upper limbs with high accuracy at home. 2 n.p. cl., 3 fig.

Description

[0001] The utility model relates to medical equipment, namely to rehabilitation robots and exoskeletons for passive development of the joints of the hand and fingers using the continuous passive mobilization method (CPM therapy).

[0002] A glove-exoskeleton with linear actuators is known from the prior art, containing linear actuators according to the number of fingers on the hand, a control module, which is a source of power for the motors and control of the direction of their rotation, belts, rings and finger cots for fastening the glove to the limbs and connecting elements for mechanical connection of the motors with the rings and finger cots, characterized in that the said connecting elements are flexible rods made in the form of twisted threads, which are fixed at one end to the shafts of the motors placed on a large bracelet, passed through through holes made in a small bracelet, and through eyes made in the lower part of the rings, ensuring the longitudinal arrangement of the threads along the forearm and their rigid attachment at their other ends to the finger cots, wherein the large and small bracelets are made with the possibility of their fastening to the forearm using belts and are connected by a rigid coupling,the length of which corresponds to the individual size of the forearm (RU Patent No. 2717046, published on 17.06.2020, Bulletin No. 17).

[0003] A disadvantage of this device is the use of flexible threads as connecting elements, which effectively transmit force only to flexion but cannot provide active, controlled finger extension, reducing the effectiveness and safety of passive therapy. Furthermore, the location of the motors on the forearm and the transmission of force through a system of threads passing through rings leads to friction losses and reduced finger positioning accuracy. The lack of a separate drive for wrist joint movement precludes comprehensive therapy of the entire hand.

[0004] An exoskeleton is known for the rehabilitation of the motor activity of the hand, comprising a housing, a fixed metacarpal element with a palm retainer mounted on the housing, and a drive connected to a mechanism for moving a movable distal phalangeal element with a retainer of the distal phalanges of the fingers, characterized in that the mechanism for moving the movable distal phalangeal element is a set of movable levers that form a spatial structure in the form of two successively located proximal and distal pairs of successively connected first and second parallelograms, wherein at the junction of the output ends of the levers of the second parallelogram of the proximal pair of parallelograms and the input ends of the first parallelogram of the distal pair of parallelograms, a movable proximal phalangeal element is placed, in the body of which an arcuate slot is made for angular movement along it, with subsequent fixation of the position,a lever for adjusting the distance between the axes of rotation of said spatial structure, which is part of the first parallelogram of the distal pair, and the flexion and extension of the exoskeleton in the axes of rotation, from the fixed metacarpal element to the proximal phalangeal element and further to the distal phalangeal element is ensured by four movable levers located at the level of the proximal phalangeal element between the levers of the proximal and distal pairs of parallelograms, wherein the position of the axes of rotation of said spatial structure is shifted in the plane of the structure beyond its limits and is selected from the condition of coinciding with the axes of rotation of the metacarpophalangeal and proximal interphalangeal joints of the hand; wherein the palm retainer and the retainer of the distal phalanges of the fingers are made replaceable (Russian Federation Patent for Utility Model No. 219183, published 04.07.2023, Bulletin No. 19).,

[0005] The disadvantage of this device is its significant complexity and, consequently, high manufacturing cost due to the large number of hinges and levers. Furthermore, the device is designed only for finger exercises and does not include a separate drive for the wrist joint, preventing comprehensive therapy of the entire hand.

[0006] A biofeedback trainer for rehabilitation of joints and muscles of the hands and fingers is known, consisting of: a control module made in the form of a hollow plastic case fixed on the patient's forearm, which contains a control microcontroller, a stepper motor controller for flexion / extension of the hand, a Bluetooth module for communication with a computer included in the trainer kit; a step-up voltage converter module for powering the stepper motors, autonomous power sources independent of the power grid for powering all electronic components and modules of the trainer; a hand flexion / extension motor module equipped with a stepper motor; a finger flexion / extension motor module; galvanic skin response monitoring sensors; a glove for fixing the hand on the finger flexion / extension module, equipped with finger pressure force sensors located inside the fingers;a computer connected to the Internet with the developed software installed thereon, characterized in that the control module additionally comprises a module for controlling the current of the hand flexion / extension stepper motor, a controller for the finger flexion / extension stepper motor, a power supply for the microcontroller and for externally connected sensors - myosensors, sensors for monitoring the galvanic skin response of the body; the hand flexion / extension motor module is located at the top center of the longitudinal axis of the hand and additionally comprises a cylindrical gearbox and an absolute encoder; the finger flexion / extension motor module additionally comprises a second stepper motor and a module for additional fastening of the finger fixation pad;a glove for fixing a hand comprises a plastic finger retainer with a T-shaped pin and a locking bar for fixing the glove fingers on the backing, as well as a bending resistor sewn into the index finger of the glove with the possibility of using it as an absolute encoder for measuring the angle of flexion of the fingers of the hand; wherein the simulator additionally comprises a bracelet made of soft fabric with two myosensors sewn into it, fixed on the forearm with a Velcro tape, and a support of the simulator on a table / bed when the patient is sitting / lying down (see Russian Patent No. 2735986, published 11.11.2020, Bulletin No. 31).;

[0007] A disadvantage of this device is the complex and material-intensive kinematic connection between the second actuator (the finger flexion / extension motor module) and the patient's fingers. This is due to the second actuator's location on the forearm and the need to transmit motion through a system of bars, racks, pinions, and pads running along the entire hand. This increases the size and weight of the wearable portion of the device, reduces transmission rigidity, and reduces the accuracy of finger positioning. Furthermore, both actuators (for the hand and fingers) are located on the forearm, placing significant strain on this area and requiring additional effort from the patient to maintain hand positioning. The prototype also does not provide for sequential activation of the actuators, which complicates the control algorithm. All of this limits the device's functionality.

[0008] The objective of the utility model is to expand the functional capabilities of the robot.

[0009] The stated task is achieved in that a rehabilitation robot for restoring fine motor skills of the hand, comprising a housing with a control unit and finger fixation elements, configured to be fixed on the forearm, is provided with two independent electromechanical drives, wherein the first drive is located in the housing and is kinematically connected to a palm support with the ability to provide flexion and extension of the hand, and the second drive is mounted on the palm support with the ability to provide flexion and extension of the fingers and is kinematically connected to the said finger fixation elements by means of rigid rods, wherein absolute encoders are installed on the shafts of the first and second drives, the outputs of which are connected to the corresponding inputs of the control unit, which is configured to sequentially activate the said drives.The range of rotation angles of the first drive is from -10° to 70°, and the range of rotation angles of the second drive is from -45° to 0°, wherein the rotation angle of -45° corresponds to the extended position of the fingers, and the rotation angle of 0° corresponds to the bent position of the fingers.

[0010] The claimed technical solution differs from the prototype in that the robot is provided with two independent electromechanical drives, wherein the first drive is located in the housing and is kinematically connected to the palm support with the ability to provide flexion and extension of the hand, and the second drive is mounted on the palm support with the ability to provide flexion and extension of the fingers and is kinematically connected to the said finger fixation elements by means of rigid rods, wherein absolute encoders are installed on the shafts of the first and second drives, the outputs of which are connected to the corresponding inputs of the control unit, which is configured to sequentially activate the said drives, and the range of rotation angles of the first drive is from -10 ° to 70 °, and the range of rotation angles of the second drive is from -45 ° to 0 °, wherein the rotation angle of -45 ° corresponds to the extended position of the fingers, and the rotation angle of 0 ° corresponds to the bent position of the fingers.

[0011] The set of claimed features ensures the achievement of the objective of the utility model - expansion of the functional capabilities of the robot.

[0012] The essence of the utility model is explained by drawings. Fig. 1 shows a general view of the rehabilitation robot. Fig. 2 shows a kinematic diagram of the robot. Fig. 3 shows a functional diagram of the device.

[0013] The rehabilitation robot comprises a body 1, which can be secured to the patient's forearm using a system of adjustable straps 2. Housing 1 houses a control unit (not shown in the figures) and a battery (not shown in the figures). Mounted within the body 1 is a first electromechanical drive 3, designed to exercise the hand.

[0014] The output shaft of the first drive 3 is kinematically connected to the palm support 5. The palm support 5 is designed to fix the patient's palm and ensure rotation of the hand in the wrist joint.

[0015] A second independent electromechanical drive 4 is mounted on the palm support 5, designed for finger flexion. The output shaft of the second drive 4 is kinematically connected to a system of rigid rods 6. Each rigid rod 6 has a fingertip 7 at its free end for attachment to the patient's finger. Rigid rods 6 ensure the transmission of both pushing and pulling forces from the drive 4 to the fingers.

[0016] The first absolute encoder 8 is installed on the shaft of the first drive 3. The second absolute encoder 9 is installed on the shaft of the second drive 4. The outputs of encoders 8 and 9 are connected to the inputs of the control unit.

[0017] The control unit is based on a microcontroller with the ability to implement PID control laws and contains drivers for controlling drives 3 and 4. The control unit memory contains a program that implements the sequential CRM therapy algorithm.

[0018] The functional diagram of the device illustrates the relationship between the main system components. The operator sets therapy parameters via the user interface, which are sent to the control unit. The control unit generates control signals for the motor drivers of the first and second drives. The drives, through gearboxes, act on the actuators (palm support and rigid rods with finger cots), ensuring flexion and extension of the patient's hand and fingers. Encoders mounted on the drive shafts continuously measure rotation angles and transmit feedback to the control unit, which compares them with the set values ​​and adjusts the control signals to minimize positioning errors.

[0019] The device operates as follows. Before the session, the device is secured to the patient's forearm and hand using straps 2 and palm support 5. Finger cots 7 are placed on the patient's fingers. Through the user interface (not shown in the figures), the operator sets the number of cycles for the hand (N1) and for the fingers (N2). After starting the program, the control unit activates the first drive 3. The signal from the first encoder 8 is used to control the rotation angle φ1 of the first drive, which determines the position of the hand. The control unit, implementing the PID law, ensures smooth flexion of the hand from the starting position to the target angle of 70°. After holding the hand in a flexed position for a specified pause (e.g., 3 seconds), the control unit initiates extension to an angle of -10° and also pauses. The "flexion-pause-extension-pause" cycle is repeated N1 times. Upon completion of the brush cycles, the control unit switches off the first drive 3 and activates the second drive 4.The signal from the second encoder 9 is used to control the φ2 rotation angle of the second drive, which determines the position of the fingers: an angle of φ2 = -45° corresponds to the extended position of the fingers, while an angle of φ2 = 0° corresponds to the flexed position of the fingers. The control unit provides N2 finger movement cycles, during which the fingers flex (change in angle φ2 from -45° to 0°) and then extend (change in angle φ2 from 0° to -45°). Upon completion of the entire procedure, the control unit returns both links to the neutral position (φ1 = 0°, φ2 = -45°) and disengages the drives.

[0020] The kinematic diagram of the device is a two-link flat manipulator, where link AB is of length corresponds to the brush, and the link BC is long corresponds to the fingers. Point A corresponds to the axis of rotation of the first actuator (the wrist joint), point B to the axis of rotation of the second actuator (the metacarpophalangeal joints), and point C to the working point (the fingertip). Angle φ1 determines the position of the hand, and angle φ2 determines the position of the fingers in accordance with the described ranges.

[0021] Placing the second actuator directly on the palm (on the palm support) shortens the kinematic chain from the actuator to the fingers, reduces the device's size, and improves the precision of movement transmission. The use of rigid rods to transmit movement from the actuator to the fingers allows for not only flexion but also active, controlled finger extension. Separate actuators with encoder feedback ensure highly accurate positioning of each component. Sequential actuator activation simplifies the control system and makes the therapy process more structured and safe.

[0022] In the specific embodiment of the utility model, the rotation angle range of the first actuator, providing flexion and extension of the hand at the wrist joint, is from -10° to 70°. The rotation angle range of the second actuator, providing flexion and extension of the fingers, is from -45° to 0°, with a rotation angle of -45° corresponding to the extended position of the fingers, and a rotation angle of 0° corresponding to the flexed position of the fingers. These ranges correspond to the anatomical limits of motion and ensure the safe use of the device.

[0023] The proposed device provides safe passive restoration of fine motor skills in patients with neurological and traumatic injuries of the upper limbs with high accuracy at home due to its compact design, dual-channel control system with position feedback and sequential activation of actuators.

Claims

1. A rehabilitation robot for restoring fine motor skills of the hand, comprising a housing with a control unit and finger fixation elements, configured to be fixed on the forearm, characterized in that it is equipped with two independent electromechanical drives, wherein the first drive is located in the housing and is kinematically connected to a palm support with the ability to provide flexion and extension of the hand, and the second drive is mounted on the palm support with the ability to provide flexion and extension of the fingers and is kinematically connected to the said finger fixation elements by means of rigid rods, wherein absolute encoders are mounted on the shafts of the first and second drives, the outputs of which are connected to the corresponding inputs of the control unit, which is configured to sequentially activate the said drives.

2. A rehabilitation robot according to paragraph 1, characterized in that the range of rotation angles of the first drive is from -10° to +70°, and the range of rotation angles of the second drive is from -45° to 0°, wherein the rotation angle of -45° corresponds to the extended position of the fingers, and the rotation angle of 0° corresponds to the bent position of the fingers.

Images