Robotic exercise chair

Abstract

The invention relates to exercise apparatus for the rehabilitation of persons with neurological disorders, and more particularly to exercise apparatus for restoring the motor function of the muscles of a person's trunk. A robotic exercise chair comprises a backrest, a seat platform, a control unit, and a power unit. The backrest consists of an inclined rod, and backrest segments arranged in pairs along said rod. The backrest segments are adjustable in terms of height and in terms of degree of extension in the sagittal plane. The seat platform consists of a seat cushion, a hexapod connected to the control unit, and legs. Mounted beneath the seat cushion are at least three strain gauges that are connected to the control unit, and the control unit contains software capable of calculating the speed and amplitude of movement of the hexapod from the readings of the strain gauges. The technical result consists in increasing the effectiveness of the rehabilitation process for persons with neurological disorders by restoring voluntary movements of the trunk.

Description

[0001] ROBOTIC TRAINING CHAIR

[0002] The invention relates to exercise machines for the rehabilitation of people with neurological disorders, namely to exercise machines for restoring the motor function of the muscles of the human torso.

[0003] For people with cerebral palsy, spinal cord injuries, strokes, or other conditions to achieve verticalization and gait, coordinated activation of all links in the body's kinematic chains, including bones, joints, muscles, tendons, nerves, fascia, and other connective tissues, is required. Standard rehabilitation protocols include stages for restoring the function of the phasic muscles, responsible for conscious, controlled movements. However, the stage for restoring the locomotor muscles, responsible for maintaining body position, is practically omitted, as it is extremely labor-intensive to implement. Rehabilitation specialists focus on early verticalization and gait stimulation, ignoring the principles of N.A. Bernstein's level theory of movement organization, according to which several levels (classes) of movement are typically involved in the organization of complex movements.If regulation of the postural muscles and the ability to independently maintain or change a person's body position are not restored, the entire torso segment containing the body's overall center of mass is excluded from the kinematic chain, effectively disrupting normal gait biomechanics. In most cases, balance reflexes in people with disabilities are partially preserved; however, their strength capabilities are functionally insufficient to independently maintain an upright torso position or voluntarily change it.

[0004] The Tolstunov orthopedic seat trainer (see, for example, https: / / argo-tema.ru / sidene-tolstunova-obschaya4nfonnatsiya Ttrril) is well-known and can be installed on any chair. With a single point of support, the trainer induces a state of unstable equilibrium, thereby engaging the vestibular system, which reflexively activates the deep spinal muscles. A disadvantage of this trainer is that it provides excessive, chaotic stimulation of muscle contractions, which leads to further destabilization in cases of muscular dystonia and trunk muscle dysfunction. This trainer is not suitable for individuals with musculoskeletal disorders who use a wheelchair, individuals with cerebral palsy with severe ataxia and dystonia, individuals with radicular syndrome and vertebral subluxations, joint instability, post-stroke complications, and the elderly.When using a seat trainer, the user also runs the risk of injury due to sudden changes in body position, falling from the trainer, or injury due to weak postural muscles. Furthermore, when using the Tolstunov trainer, the user requires additional support during exercises.

[0005] The Huber 360 exercise machine from LPG (see https: / / www.lpqmedical.com / en / professional-area / huber / ) is a motorized platform for coordination training, equipped with sensors that allow training on both a moving and stationary platform, while receiving full biofeedback data. The machine's software analyzes and displays the user's center of mass during training, allowing them to adjust their actions and position on the platform. The machine is designed for use in a standing position, but a seat can be added for seated exercises. A drawback of this machine is that its seat does not ensure precise positioning of the user—the user may "slide," which shifts the focus of the exercise from one muscle group to another.The exercise machine has only two degrees of freedom, which limits the platform's range of motion to impact the user's musculoskeletal system. It's also not particularly suitable for those who have difficulty sitting independently, as it requires a high level of voluntary pelvic and torso movement. Furthermore, the strain gauge sensor sampling rate is low (40 Hz), reducing the effectiveness of movement control.

[0006] A modular orthopedic exercise chair is known: (see Russian Patent No. 2423961, published July 20, 2011), containing a control computer and consisting of hingedly connected modules - supports for the corresponding segment of a human joint, connected to this segment using soft orthoses. The support modules are interconnected by pivots such that one of the pair of connected modules serves as the base of the drive, and the second is connected to the output shaft of this drive via a strain gauge. The base of the exercise chair is the backrest of the chair. The housing of a roller-screw linear electric drive is rigidly connected to it. The output shaft of this drive is connected via a strain gauge to the knee support at the area of ​​its articulation with the ankle support. The shoulder segment support, which serves as the base of the rotary electric drive, is also connected to the backrest of the chair.The latter's output shaft is connected via an angular link and a fork to a mechanical dipole mounted in two hemispherical supports rigidly connected to the shoulder support. The mechanical dipole is connected to the elbow support via a strain-gauge-measured elastic beam. These mechanisms in the exercise chair are configured as left and right mechanisms, controlled separately by controllers whose data inputs are connected to a single processor and secondary inputs and outputs from force sensors that detect the forces generated when "test movements" are assigned to the supports. Signals from the sensors convey information about the muscle response to the "test movement." A drawback of the exercise chair is that it remains unclear how it will adapt to contractures and spasticity in individuals with spinal cord injury and cerebral palsy, as they cannot be passively taught correct movements. Attempting to overcome spasticity and contractures by force or insufficiently fine-tuning the force on the exercise chair may result in injury to the user.Furthermore, the torso segment is immobilized, meaning the device only works on the limbs, not the torso. Biomechanically, the torso muscles act as a hub for force transmission between the upper and lower limbs. Without restoring trunk muscle function, limb training has limited practical application. Limb movements prevent the ability to perform the integrated motor actions needed in everyday life.

[0007] A training device (Patent No. CN201930463, published August 17, 2011) is a verticalizer with an assistive function based on pressure sensors in the support surfaces. It corresponds to a method for restoring motor functions with partial compensation for gravity, creating easier conditions for movement. However, assistive support is provided only in one sagittal plane (forward-backward movements). Movement in the frontal plane (right-left) is not supported. This significantly limits the applicability of training with the device for restoring self-care skills. Furthermore, the device's single-degree-of-freedom kinematics, even with pressure sensors, does not allow for consideration and correction of individual biomechanical compensations (for example, a patient with spastic hemiplegia (paralysis of an arm and leg on one side) will rise from a prone to a sitting position primarily using the intact side).This means external monitoring by a specialist is necessary to restore motor function and avoid a one-sided recovery. The device description remains unclear about how the device adapts to a specific person's anthropometric characteristics: for example, whether the length of the leg or torso section can be adjusted to target the correct points of application of assistive technology to restore voluntary movement.

[0008] The closest technical solution to the claimed solution is a training device (patent CN208927520, published June 4, 2019), comprising a pedestal, a column, a seat, an L-shaped support, a backrest, armrests, and a tilt angle sensor. The lower end of the column is rigidly connected to the pedestal. The side of the column is rigidly connected to the L-shaped support. The backrest and armrests are installed in the L-shaped support. The upper part of the column is connected to the seat via a cam mechanism, which includes a seat flange, a flange plug, a limit plate, a column flange, and a bearing for a swivel joint with a straight rod. The device's pedestal is thus spring-loaded, and the user tilts it independently, shifting their body weight according to the system's settings.A drawback of the device is that it is not suitable for people with severe mobility limitations, as they will use shoulder and head movements—a voluntary movement—to tilt the seat, followed by passive pelvic tilt. The user's positional alignment remains unclear. Since the seat's mounting axis is fixed, it's possible to "miss" the correct position when transferring from a wheelchair, causing the tilt axis to misalign with the body's axis, leading to improper biomechanics. Furthermore, the issue of vibration is unclear; the device description doesn't indicate the spring stiffness or whether vibration occurs during movement. Given the secondary renal and hepatic pathology common in people with spinal cord injuries, vibration may be undesirable. This also concerns the high risk of thrombosis in this category of users.

[0009] The objective of the claimed technical solution is to develop a training device for the rehabilitation of people with neurological disorders with the ability to precisely dose changes in the position of the user's pelvis in a sitting position.

[0010] The technical result of the invention consists in increasing the effectiveness of the rehabilitation process for people with neurological disorders by restoring voluntary movements of the torso.

[0011] The technical result is achieved in that the robotic exercise chair consists of a backrest and seat platform, a control unit, and a power supply. The backrest consists of a tiltable rod and backrest segments arranged in pairs along the rod. Each backrest segment is adjustable for height and depth in the sagittal plane. The backrest rod is fixed perpendicular to the seat platform, and the seat platform consists of a seat cushion, a hexapod connected via a communication channel to the control unit, and legs. At least three strain gauges are mounted under the seat cushion and connected via a communication channel to the control unit, and the control unit contains preinstalled software capable of calculating the speed and amplitude of the hexapod's motion based on strain gauge data.

[0012] The seat cushion can be equipped with pressure sensors and temperature sensors connected via a communication channel to the control unit.

[0013] Strain gauge sensors can be implemented with a sampling rate from 20 to 320 Hz. The backrest segment can contain a linear actuator and a pressure sensor connected via a communication channel to the control unit.

[0014] The claimed invention is explained by a figure which depicts a schematic structure of a training chair.

[0015] The numbers indicate the following:

[0016] 1 - back segments,

[0017] 2 - seat cushion,

[0018] 3 - adjustable backrest,

[0019] 4 - seat cushion base,

[0020] 5 - hexapod,

[0021] 6 - control unit,

[0022] 7 - folding legs,

[0023] 8 - power supply.

[0024] The robotic exercise chair consists of two movable and independent parts: the seat platform and the backrest.

[0025] The backrest 3 consists of a rod, which is attached to the seat platform, namely, to the base of the hexapod 5, and has an adjustable angle of inclination, and segments of the seat back 1. A perforated fastening gusset with holes corresponding to different angles of inclination of the backrest 3, into which a locking device can be inserted, is installed at the junction of the rod with the base of the hexapod 5 as a tool for adjusting the inclination of the backrest 3. The segments of the backrest 1 are arranged in pairs along the rod and in each pair are connected by a bar and secured to the rod with the ability to adjust the height of their position. The backrest 3 includes three pairs of segments 1 - lumbar, thoracic, and scapular. Each segment of the backrest 1 is designed with the ability to adjust the depth of extension in the sagittal plane, for example, mechanically by extending the desired segments and fixing them.Adjusting the backrest segments 1 in height and reach in the sagittal plane expands the possibilities for targeted stimulation of the user's deep torso muscles. In the future, backrest 3 could also be robotized and synchronized with the seat platform. For example, linear actuators and pressure sensors could be added to the backrest segments 1, connected via a communication channel to control unit 6. Thus, the exercise chair will have not one (seat), but two automated support surfaces (seat and backrest) to better manage changes in the user's posture. For example, as back muscle function recovers, the support height will decrease (to the lumbar region only, instead of the lumbar-thoracic-scapular region).

[0026] The seat platform consists of an upper part - a seat cushion 2, which is in direct contact with the user's body, a seat cushion base 4, a hexapod 5, a control unit 6 of the exercise chair, folding legs 7 and a power supply unit 8. The seat cushion 2 is profiled and has an overhang in the middle to give it the anatomical shape of the human pelvis for the purpose of better centering the position of the user's body on it. The base of the seat cushion 4 is equipped with at least three strain gauge sensors with a sampling frequency of 20 to 320 Hz, connected via a communication channel to the control unit 6. The seat cushion 2 can be additionally equipped with uniformly distributed pressure sensors (of the pressure map type) and temperature, connected via a communication channel to the control unit 6. To best ensure communication between the seat platform and the control unit 6, the exercise chair must contain at least 36 sensors of each type.Hexapod 5 provides precise pelvic positioning for a seated person by varying the spatial position of seat cushion 2. The classic hexapod design (Gugh-Stewart platform) has six degrees of freedom, ensuring high precision and smooth movement of the entire seat platform, unattainable by competing solutions with similar operating principles, which utilize different kinematic designs. Hexapod 5 is a well-known design and includes six precision linear actuators driven by hexapod control unit 5, which is represented by control unit 6. Located on the base of hexapod 5 is the exercise chair control unit 6, a computer with pre-installed software capable of analyzing data from all the sensors and activating the automated components of the chair.Folding legs 7 can be rotated to increase support area and improve stability. Power supply 8 is connected via a communication channel to control unit 6 of the exercise chair and can be either installed separately or integrated into the seat platform.

[0027] The chair-style design of the exercise machine is based on the fact that the human body's overall center of mass is located in the torso. Thus, by directly targeting the heaviest segment of the body and reducing the number of links in the kinematic chain, overall motor control is facilitated by reducing the number of excess degrees of freedom. The sitting position is relatively stable, making the exercise more accessible for people with severe motor limitations. Furthermore, people with disabilities spend most of the day in a sitting position (as do most otherwise healthy people), so corrective interventions are easily integrated into this scenario without interfering with other daily activities.The position of the pelvis determines the position of the spine, head, and overall spatial orientation, which is especially important for people with nervous system disorders and the elderly who experience impaired coordination and spatial orientation. The intersection points of the largest number of kinematic chains in the human body are located in the pelvic region, so any impact on the pelvic position causes the greatest shifts in the overall biomechanics of the entire human body.

[0028] The robotic exercise chair operates as follows. A user with neurological impairments is seated on seat cushion 2. The exercise chair is turned on using power supply 8. The height of the folding legs 7, the height of the backrest segments 1, and their reach in the sagittal plane are adjusted to accommodate the user's spinal curvature. A test program (lasting approximately 1 minute) is then launched on control unit 6. This program sends signals to the linear actuators of hexapod 5, tilting the seat platform in various directions relative to the vertical axis of the user's torso. This triggers equilibrium reactions in the user (they attempt to maintain an upright torso). Simultaneously, strain gauges record the movement of the body's overall center of mass in response to changes in seat position and transmit the corresponding signals to control unit 6.Thus, the data obtained from the strain gauge sensors allows us to understand the user's control of their torso. Control unit 6 software interprets these signals as information about how well the user can return their overall center of mass to its original neutral position when the inclination of the support surface changes. It also calculates the speed at which the user can return to the starting position and the directions in which they perform better / worse. Based on this data, it then creates a user profile (or refines it if the user is reusing the exercise machine) and creates a personalized motor function recovery program.

[0029] Following the initial testing, a motor function restoration program is launched based on its results. Strain gauge sensors record changes in the position of the overall center of mass and send corresponding signals to control unit 6, reflecting the movement of the projection of the body's overall center of mass onto the seat surface as its position changes during hexapod operation. The software then plots the trajectories of the user's overall center of mass and compares them with those of otherwise healthy individuals. Based on the data received from the strain gauge sensors, control unit 6 sends a signal to hexapod 5, adjusting the trajectory of hexapod 5's movement (speed and amplitude) in accordance with the user's individual motor characteristics to improve the trajectory of the user's overall center of mass.The dynamic change in the user's pelvic position in the exercise chair also changes the position of the ribcage and activates the suction effect of the diaphragm, facilitating overall venous return of blood to the heart, thereby reducing the risk of cardiovascular disease. This is significantly more effective than using ergonomic furniture, which maintains the correct but static body position.

[0030] Simultaneously, temperature sensors (if present) continuously record blood circulation in the user's lower extremities and transmit a corresponding signal to the software in control unit 6. People with neurological disorders often experience cold extremities. During a training session, the torso and pelvic girdle are activated, thereby stimulating blood circulation in the lower extremities. Based on data from the temperature sensors, the software in control unit 6 generates a temperature map of the user's posterior thighs and buttocks and analyzes the nature of vascular tone in the body segments in contact with the seat surface. This allows for an assessment of the current quality of biological fluid circulation and prompt adjustments to the motion algorithms of the entire robotic chair.Pressure sensors (if present) continuously record the pressure distribution across the seat platform surface, allowing the user's posture to be determined. The pressure sensors send corresponding signals to control unit 6. Based on the data received from the temperature and pressure sensors (if present), the software compares these readings with normal values ​​and identifies a method for maintaining the user's balance, thereby normalizing blood circulation in the pelvic region and lower extremities.

[0031] Thus, the proposed invention allows for the restoration of the normal functioning of the user's postural-tonic muscles from session to session and significantly improves the process of his rehabilitation.

[0032] The claimed invention has the following advantages:

[0033] - no contraindications for use, since the exercise chair does not provide massage or physiotherapy effects and is suitable for all categories of users;

[0034] - the ability to quickly adjust the movement algorithms of the entire robotic exercise chair;

[0035] - The active mobility of the exercise chair compensates for the negative changes in blood flow in the pelvic area and lower extremities caused by prolonged sitting, normalizes microcirculation in body tissues, and creates the conditions for improving the user's reproductive function; - Regular use of the exercise chair facilitates the overall venous return of blood to the user's heart, thereby reducing the risk of cardiovascular disease; the ability to conduct early detection of signs of neurodegenerative diseases based on the changing nature of motor function control by the central nervous system;

[0036] - the ability to recreate the kinematics of a classic pendulum with different axis lengths, which allows for localization of the impact on specific areas of the deep muscles of the body and precise dosing to increase the effectiveness of rehabilitation procedures;

[0037] - the ability to improve the quality of nutrition of brain tissue by automatically changing the position of the seat platform in the vertical plane, which allows changing the position of the user's head and, in particular, the cervical spine and the tone of its muscles, affecting the blood flow in the carotid arteries;

[0038] - the ability to engage most of the muscle fibers that are subject to atrophy from inactivity during prolonged sitting in classic ergonomic chairs or in a wheelchair;

[0039] - improving the overall biomechanics of the user's body.

Claims

CLAUSES OF THE INVENTION 1. A robotic exercise chair consisting of a backrest and a seat platform, a control unit and a power supply unit, characterized in that the backrest consists of a rod configured to tilt and backrest segments arranged in pairs along the rod, wherein each backrest segment is configured to be adjustable in height and in the depth of reach in the sagittal plane, the backrest rod is fixed perpendicular to the seat platform, wherein the seat platform consists of a seat cushion, a hexapod connected via a communication channel to the control unit, and legs, wherein at least three strain gauge sensors are installed under the seat cushion, connected via a communication channel to the control unit, and the control unit contains pre-installed software with the ability to calculate the speed and amplitude of movement of the hexapod based on the data from the strain gauge sensors.

2. A robotic exercise chair according to paragraph 1, characterized in that the seat cushion is equipped with pressure sensors and temperature sensors connected via a communication channel to the control unit.

3. A robotic exercise chair according to paragraph 1, characterized in that the strain gauge sensors are made with a polling frequency of 20 to 320 Hz.

4. A robotic exercise chair according to claim 1, characterized in that the backrest segment contains a linear actuator and a pressure sensor connected via a communication channel to the control unit.

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