WO2025221156A1 - Robotic exercise chair - Google Patents

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

ROBOTIC TRAINING CHAIR

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.

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.

The Tolstunov orthopedic seat trainer (see, for example, https://argo-tema.ru/sidene-tolstunova-obschaya4nfonnatsiya Ttrril), which can be installed on any chair, is well-known. Having 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 the trainer is that it provides excessive, chaotic stimulation of muscle contractions, which This leads to further destabilization in cases of muscular dystonia and trunk muscle dysfunction. This exercise machine is not suitable for individuals with musculoskeletal disorders, wheelchair users, individuals with cerebral palsy with severe ataxia and dystonia, individuals with radicular syndrome and vertebral subluxations, joint instability, stroke survivors, and the elderly. Furthermore, when using the seat trainer, the user is at risk of injury due to sudden changes in torso position, falls, or injury due to weakness of the postural muscles. Furthermore, when using the Tolstunov trainer, the user requires additional support during exercises.

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 machine has only two degrees of freedom, which limits the platform's ability to move to influence the user's musculoskeletal system. The exercise machine is 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), which reduces the effectiveness of movement control.

A modular orthopedic exercise chair is known: (see Russian patent No. 2423961, published on July 20, 2011), containing a control computer and consisting of hinged modules - supports for the corresponding segment A human joint connected to this segment using soft orthoses. The module supports are pivotally connected to each other such that one of the paired modules serves as the base of the drive, while the other is connected to the output shaft of this drive via a strain gauge. The base of the exercise machine is the backrest of the chair. The housing of the roller-screw linear electric actuator is rigidly connected to it. The output shaft of this drive is connected via a strain gauge to the knee support at the 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 output shaft of the latter is connected via an angular link and a fork to a mechanical dipole mounted in two hemispherical bearings rigidly connected to the shoulder support. The mechanical dipole is connected to the elbow support via a strain gauged elastic beam. The listed mechanisms in the exercise chair are implemented as left and right mechanisms, controlled separately from the controllers, whose data inputs are connected to a single processor and the secondary inputs and outputs of the force sensors generated when "test movements" are assigned to the cradle. The 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 people 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 can lead to injury to the user. Furthermore, the torso segment is immobilized, meaning the device only works with the limbs, not the torso. Biomechanically, the torso muscles act as a hub for force transmission between the upper and lower limbs; without restoring the function of the torso muscles, limb training has limited practical application. Movements in the limbs do not allow for the ability to perform the complete motor acts that a person needs in everyday life.

A training device (Patent No. CN201930463, published August 17, 2011) is a verticalizer with an assistive function based on pressure sensors in the supporting surfaces. It corresponds to a method for restoring motor functions with partial compensation for gravity. - creates 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 the device for rehabilitation of self-care skills. Furthermore, the device's single-degree-of-freedom kinematics, even with pressure sensors, does not allow for the 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 using primarily the intact side). Therefore, external monitoring by a specialist is necessary to restore motor function and avoid one-sided recovery. The device description remains unclear as to how the device adapts to the anthropometric characteristics of a specific individual: for example, whether the length of the leg or torso sections can be adjusted to establish the correct points of application of assistive aids to restore voluntary movement.

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 the shoulder girdle and head to tilt the seat—a voluntary movement—and then the pelvis will tilt passively. The issue of user centering remains unclear. Since the seat's mounting axis is fixed, it's possible to "miss" the seat when transferring a person from a wheelchair. Then, the tilt axis won't align with the body axis, leading to incorrect biomechanics. Furthermore, the issue of vibration is unclear; the device description doesn't indicate how stiff the springs are or whether there is vibration 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 blood clots in this category of users.

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.

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.

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.

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

Strain gauge sensors can be manufactured with a sampling frequency from 20 to 320 Hz. The backrest segment may contain a linear actuator and a pressure sensor connected via a communication channel to the control unit.

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

The numbers indicate the following:

1 - back segments,

2 - seat cushion,

3 - adjustable backrest,

4 - seat cushion base,

5 - hexapod,

6 - control unit,

7 - folding legs,

8 - power supply.

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

The backrest 3 consists of a rod that 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. As a tool for adjusting the inclination of the backrest 3, a fastening perforated gusset with holes corresponding to different angles of inclination of the backrest 3, into which a lock can be inserted, is installed at the junction of the rod with the base of the hexapod 5. 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 the location. The backrest 3 includes three pairs of segments 1 - lumbar, thoracic, scapular. Each segment of the backrest 1 is made with the ability to adjust the depth of reach in the sagittal plane, for example, mechanically by extending the desired segments and fixing them. Providing the ability to adjust the segments of the backrest 1 in height and reach in the sagittal plane expands the possibilities of targeted action on the deep muscles The user's torso. 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 segments of backrest 1, connected via a communication channel to control unit 6. Thus, the exercise chair would 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 would decrease (to just the lumbar region instead of the lumbar-thoracic-scapular region).

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. For the best possible communication between the seat platform and the control unit 6, the exercise chair must contain at least 36 sensors of each type. The hexapod 5 ensures precise positioning of the pelvis of a seated person by changing the position of the seat cushion 2 in space. The classic hexapod design (Gugh-Stewart platform) has six degrees of freedom, which ensures high precision and smoothness of movement of the entire seat platform, which is unattainable by the most similar competing solutions in terms of the operating principle, built using a different kinematic scheme. The design of hexapod 5 is known and includes six precision linear actuators, driven by the hexapod control unit 5, which is used as control unit 6. The control unit 6 of the exercise chair is located on the base of hexapod 5, which is a computer with pre-installed software, designed with the ability to analyze the readings of all the specified sensors and set The movement of the chair's automated elements. 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 located separately or integrated into the seat platform.

The chair-style exerciser is designed because 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 excess degrees of freedom. The sitting position is relatively stable, making the exercise more accessible for individuals with severe motor limitations. Furthermore, individuals with disabilities spend most of their day sitting (as do most otherwise healthy individuals), so corrective interventions can easily be integrated into this scenario without interfering with other daily activities. Pelvic position determines the position of the spine, head, and overall spatial orientation, which is especially important for those with impaired coordination and spatial orientation in individuals with nervous system impairments and the elderly. The intersection points of the largest number of kinematic chains in the human body are located in the pelvic region, so impacting the pelvic position causes the greatest shifts in the overall biomechanics of the entire body.

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, and the height of the folding legs 7, the height of the backrest segments 1, and their reach in the sagittal plane are adjusted according to the curvature of the user's spine. A testing program (lasting approximately 1 minute) is then launched on control unit 6, which sends signals to the linear actuators of hexapod 5, tilting the seat platform in different directions relative to the vertical axis of the user's torso. This induces equilibrium reactions in the user (they try to maintain an upright torso position). Simultaneously, strain gauge sensors The sensors 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. The data obtained from the strain gauges thus allows us to understand the user's control of their torso. Control unit 6's 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 with which the user can return to the original position and the directions in which they perform this "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 rehabilitation program.

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. Dynamic changes in the user's pelvic position also alter the position of the ribcage and activate the suction effect of the diaphragm, facilitating overall venous return of blood to the heart, thereby reducing the risk of cardiovascular disease. This happens much more effectively than when using ergonomic furniture, which gives the body a correct, but static position.

At the same time, temperature sensors (if present) continuously record the level of 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. Using data from temperature sensors, the software in control unit 6 creates 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 one to assess the quality of biological fluid circulation at a given moment and promptly adjust the movement algorithms of the entire robotic chair. Pressure sensors (if present) continuously record the pressure distribution across the surface of the seat platform, allowing one to determine the user's posture on the exercise chair. The pressure sensors send the corresponding signals to control unit 6. Based on the data received from the temperature and pressure sensors (if present), the software compares the readings with normal values and identifies a method for maintaining the user's balance, which helps normalize blood circulation in the pelvic area and lower extremities.

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.

The claimed invention has the following advantages:

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

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

- the active mobility of the exercise chair compensates for negative changes in blood flow in the pelvic area and lower extremities due to 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 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 control by the central nervous system;

- 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;

- 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;

- 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;

- 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.