WO2021066670A1

WO2021066670A1 - Method for recognizing phases of a complex movement using emg signal processing

Info

Publication number: WO2021066670A1
Application number: PCT/RU2019/000698
Authority: WO
Inventors: Анатолий Сергеевич БОБЕ
Original assignee: Общество С Ограниченной Ответственностью "Нейроассистивные Технологии"
Priority date: 2019-10-02
Filing date: 2019-10-02
Publication date: 2021-04-08

Abstract

The invention relates to methods for controlling an upper or lower limb exoskeleton based on the processing of EMG signals during muscle contraction. The present control method includes the following steps: a) the calibration of an upper or lower limb exoskeleton in order to obtain a set of core movements for each type of movement stipulated in a training program, wherein each type of core movement is characterized by at least one movement phase which is identified during the recording and processing of an EMG signal, and each movement phase is characterized by the values of specific amplitude-time characteristics; b) the selection, by the user, of the desired type of movement from the set of movements; c) the recording of an EMG signal during contraction of the active muscles of the user's upper or lower limbs; d) the processing of the EMG signal to identify the current movement phase and its correspondence to a core movement phase; g) the execution, by the user, of the next movement phase in accordance with the selected movement type; h) the repetition of steps c)-f) until completion of the final movement phase of the selected movement type being performed by the user; the repetition of steps b)-h) until completion of the training program. The technical result of the invention is more efficient recognition of a complex movement.

Description

PHASE RECOGNITION METHOD OF COMPLEX MOTION BASED ON EMG SIGNAL PROCESSING

FIELD OF TECHNOLOGY

The invention relates to medicine, namely to methods for controlling the exoskeleton of the upper or lower extremities based on processing EMG signals during muscle contraction, during rehabilitation and restoration of motor functions of a user with impaired musculoskeletal functions.

LEVEL OF TECHNOLOGY

The known method of bionic control of a technical exoskeleton, disclosed in RU 2627818 C1, publ. 11.08.2017. The method includes generating a control action by registering an electrophysiological signal from a contracting muscle, processing it, sending a signal to a control unit and then to an actuator. In this case, as an electrophysiological signal, the electrical impedance from the antagonist muscles is recorded during the natural movement of these muscles; to register the impedance, an alternating electric current is passed through the muscles, the current value of the degree of limb flexion is calculated, and the obtained value is used as a control signal.

The disadvantage of the known technical solution is the impossibility of recognizing complex movements consisting of several simple movements.

In addition, a method for controlling an exoskeleton is known from the prior art, which includes preliminary calibration of the claimed device when registering EMG signals to determine and save a set of basic movements, supplying the control mechanisms of the device for the user to perform the necessary movement after registering the current movement based on the processing of the current EMG signal and identifying the current motion with the stored base motion.

The disadvantage of the above-disclosed technical solution is the impossibility of recognizing complex movements consisting of several simple movements.

DISCLOSURE OF THE INVENTION

The object of the claimed invention is to develop a method for controlling the exoskeleton of the upper or lower extremities, which makes it possible to recognize a complex movement (human step), consisting of several phases (simple movement - pushing off the leg).

The technical result of the invention is to improve the efficiency of recognition of complex motion.

The specified technical result is achieved due to the fact that the method for controlling the exoskeleton of the upper or lower extremities to perform a training program, including a set of movements necessary for the user to perform, the method includes the following steps: a) Calibration of the exoskeleton of the upper or lower extremities to obtain a set of basic movements performed by the user for each type of movement according to the training program, while each type of basic movement performed by the user is characterized by at least one phase of movement, and each phase of movement is determined upon registration and processing the EMG signal based on the following values of the amplitude-temporal characteristics: the average duration of the phase, the set of active and inactive muscles, the average level of tension of active muscles during the movement phase;

B) The user selects the required type of movement from the set of movements according to the training program and starts the movement by the user according to the selected type of movement; c) Registration of an EMG signal for the contraction of active muscles of the corresponding (upper or lower) limbs of the user; d) Processing of the EMG signal to determine the current phase of movement performed by the user, while the current phase is characterized by the following values of the amplitude-temporal characteristics: the average duration of the phase, the set of active and inactive muscles, the average level of tension of active muscles during the movement phase; e) Comparison of the determined current phase of movement performed by the user with at least one basic phase of movement to determine the type of movement performed by the user; f) Signaling the control mechanisms of the exoskeleton of the upper or lower extremities to support the user by the exoskeleton during a certain current phase of movement that coincides with the basic phase of movement; e) Execution by the user of the next phase of movement, according to the selected type of movement; h) Repetition of steps c) -f) until the end of the final phase of the movement of the selected type of movement performed by the user. i) Repetition of steps b) -h) until completion of the workout.

At least one basic phase of movement performed by the user for each type of movement, when calibrating the exoskeleton of the upper or lower extremities, is determined by processing the EMG signal on the basis of 5-7 repetitions of each type of movement of the exoskeleton of the upper or lower extremities performed by the user.

At least two different types of movements performed by the user, having at least one identical phase of movement, additionally the current phase and each basic phase of movements performed by the user, are additionally determined during registration and processing of the EMG signal based on the value of the amplitude time characteristic - change in the level of tension of active muscles during the movement phase.

When calibrating the exoskeleton of the upper or lower extremities to preserve at least two different types of movements having at least one identical phase of movement, each basic phase of these types of movements performed by the user is determined during registration and processing of an EMG signal on the basis of 5-7 repetitions performed by the user at least two different types of movement, having at least one identical phase of movement.

If a certain phase of movement performed by the user does not coincide with the basic phase of movement, the exoskeleton performs the corresponding current basic phase of movement for the user.

The calculated and current amplitude-time characteristics are displayed on the screen for the user.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be better understood from the description, which is not limiting and given with reference to the accompanying drawings, which depict:

FIG. 1 - Scheme of exoskeleton operation control.

FIG. 1 - Amplitude-time characteristic of the performed complex movement (walking), divided into phases of movement, based on the processing of the EMG signal according to the claimed invention for the lower extremities

FIG. 2 - Amplitude-time characteristic of the performed complex movement (rearrangement of an object to a new place), divided into phases of movement, based on the processing of the EMG signal for the upper limbs

CARRYING OUT THE INVENTION

The method of controlling the exoskeleton of the upper or lower extremities to perform a training program that includes a set of movements required to perform the movements performed by the user (for the lower extremities, the set of movements performed by the user is selected, for example, from the following complex movements: walking and placing the leg on a support located on height; for the upper limbs, a set of movements performed by the user is selected, for example, from the following complex movements: lifting the cup and shaking hands), is carried out as follows.

The exoskeleton is fixed on the corresponding (upper or lower) limbs of the user, the corresponding limbs of the user are fixed with electrodes that allow recording EMG signals during muscle contraction. For the lower extremities, EMG signals are recorded, for example, by the contraction of the anterior tibial and soleus muscles, and for the upper extremities, EMG signals are recorded, for example, by the contraction of the radial muscle and biceps. Then the exoskeleton is calibrated to obtain a set of basic movements performed by the user for each type of movement according to the training program, which are stored in the exoskeleton memory. To do this, a user with an exoskeleton of the corresponding (upper or lower extremities) attached to it makes 5-7 repetitions of each movement, which will be performed from a set of movements according to the training program. In the course of movement during the calibration of the lower limb exoskeleton, the registered EMG signals are amplified in the biomplifier, and then enters the processing unit, in which the EMG signal is converted into an amplitude-time characteristic, which has corresponding values for each type of movement, while in the processing unit each the type of movement is divided into several successive phases of movement (movements from one phase refer to simple (one-phase) movements), while each phase of movement is an amplitude-time characteristic, on the basis of which the corresponding set (number) of active and inactive muscles for each phase is determined ... Additionally, for each phase of movement, the following values of the amplitude-time characteristic are determined: the average duration of the phase and the average level of tension of active muscles during the phase of movement (which makes it possible to more accurately determine the various phases of movement). The division into phases of movement is carried out on the basis of a constant set of active and inactive muscles over time, the sequence of changes in the set of active and inactive muscles determines the sequence of phases of movement for each type of movement performed by the user. In this case, for example, the walking movement in the processing block is divided into the following phases: pushing off the leading leg, moving the leading leg, setting the leading leg, lifting the second leg, pulling the second leg, setting the second leg, and, for example, lifting the cup, in the block processing is divided into the following phases: gripping the cup and lifting the cup. However, some complex movements consist of one phase, for example, flexion of a toe or leg. In this case, the processing unit determines that the current movement consists of one phase. In the process of calibrating the exoskeleton, the exoskeleton's spatial movements are stored in the memory of the exoskeleton.

After calibrating the exoskeleton, the user on the screen selects the required type of movement from a set of movements according to the training program and starts the movement of the selected type of movement, while during the movement performed by the user, the EMG signal is recorded to contract the active muscles of the corresponding (upper or lower) extremities;

The registered EMG signal is sent for processing to the processing unit, where, based on the processing of the EMG signal, the current phase of the movement performed by the user is determined. In the processing unit, the EMG signal is converted into an amplitude-time a characteristic, on the basis of which a set of active and inactive muscles is determined, corresponding to the current phase of movement of the exoskeleton. Additionally, on the basis of the amplitude-time characteristic, the following values are determined: the average duration of the phase and the average level of tension of active muscles during the movement phase.

Then, the processing unit compares the determined current phase of movement performed by the user with at least one basic phase of movement to determine the type of movement performed by the user. Based on the coincidence of the current phase and the basic phase, the type of movement performed by the user is determined based on the current phase of movement, which corresponds to the basic phase of movement from the saved set of basic movements of the exoskeleton. Comparison of the current phase and the basic phase of movements also makes it possible to distinguish between different types of movement performed by the user with the exoskeleton attached to it.

After that, when the current phase and the basic phase of movements coincide, the microcontroller sends a signal to the control mechanisms of the exoskeleton of the corresponding (upper or lower) limbs for the exoskeleton to support the user when performing a certain current phase of movement from the selected type of complex movement according to the training program (the exoskeleton is in passive mode) ... If a certain current phase of movement does not coincide with the basic phase of movement, the exoskeleton performs the corresponding current basic phase of movement for the user, while the exoskeleton switches to the assistive mode. After the end of the execution of the exoskeleton for the user corresponding to a certain current phase of movement, the exoskeleton goes into passive mode.

When the user finishes executing the current phase of movement, the user proceeds to the beginning of the execution by the user of the next phase of movement of the selected type of movement.

Then, the above-described sequence of operations of the control method, namely: registration of the EMG signal, processing the EMG signal, comparing a certain current phase of movement, sending a signal to the control mechanisms of the exoskeleton and performing the next phase of movement by the user is repeated until the end of the final phase of movement of the selected type of movement performed user. If the selected movement type according to the training program consists of one phase, then the current movement phase is the final phase of the movement for the selected movement type according to the training program.

At the end of the final phase of the movement of the selected type of movement performed by the user, the sequence of operations of the control method described above, namely: the user selects the next required type of movement from a set of movements according to the training program and the implementation of the beginning of the movement of the selected type, the movement, registration of the EMG signal, processing the EMG signal, comparing a certain current phase of movement, sending a signal to the control mechanisms before completing the training program.

If the user needs to perform, for example, two different types of movement that have at least one identical phase of movement (raising the cup and raising the sugar bowl), then the current phases and basic phases of the movements of the specified types of movement performed by the user are additionally determined during registration and signal processing EMG based on the value of the amplitude-time characteristic - the change in the tension level of active muscles during the movement phase. In this case, when calibrating the exoskeleton of the corresponding (upper or lower extremities), each basic phase performed by the user is determined during the registration and processing of the EMG signal on the basis of 5-7 repetitions performed by the user of at least two different types of movement, having at least one the same phase of movement. Based on a certain set of active and inactive muscles, the above types of movements in the processing unit are divided into identical phases (grasping an object and lifting it), according to the different value of the amplitude-time characteristic - the change in the tension level of active muscles during the movement phase is determined by the type of movement (lifting sugar bowls or raising a cup), because lifting these objects requires a different effort, therefore, a different level of tension of active muscles during the phase of movement, while this level increases with increasing weight of the object, i.e. the above additional amplitude-time characteristic allows us to distinguish between different types of movement from each other, including from the phase of movement where differences are observed (raising a sugar bowl or raising a cup). Amplitude-temporal characteristic - the change in the level of tension of active muscles during the phase of movement, is not limited to the ability to recognize movements with the same phase of movement, because allows you to recognize any movements of the upper or lower extremities in addition to or instead of amplitude-temporal characteristics: a set of active and inactive muscles for each phase, the average duration of the phase and the average level of tension of active muscles during the movement phase.

The calculated (baseline) and current amplitude-time characteristics are displayed on the screen for the user, which allows the subject to analyze the correctness of the current phase of movement.

Experiments have shown that the claimed method improves the efficiency of recognition of a complex movement by decomposing a complex movement into a sequential series of simple movements, each of which is characterized by significantly higher accuracy and ease of recognition by compared to the recognition accuracy of complex motion. At the same time, a long-term complex movement can be recognized in real time, and not based on the results of its completion. At the same time, the recognized complex movement corresponds as much as possible to the natural movement of a healthy person. The invention has been disclosed above with reference to a specific embodiment. Other embodiments of the invention may be obvious to specialists without changing its essence, as it is disclosed in the present description. Accordingly, the invention should be considered limited in scope only by the following claims.

Claims

CLAIM

1. A method of controlling an exoskeleton of the upper or lower extremities to perform a training program that includes a set of movements necessary for the user to perform, the method includes the following steps: a) Calibration of the exoskeleton of the upper or lower extremities to obtain a set of basic movements performed by the user for each type of movement according to the training program, while each type of basic movement performed by the user is characterized by at least one phase of movement, which is determined during registration and processing of the EMG signal, and each phase of movement is characterized by the following values of amplitude-time characteristics: average duration of a phase, a set of active and inactive muscles, the average level of tension of active muscles during the movement phase;

B) The user selects the required type of movement from the set of movements according to the training program and starts the movement by the user according to the selected type of movement; c) Registration of an EMG signal for the contraction of active muscles of the user's upper or lower extremities; d) Processing of the EMG signal to determine the current phase of movement performed by the user, while the current phase is characterized by the following values of the amplitude-time characteristics: the average duration of the phase, the set of active and inactive muscles, the average level of tension of active muscles during the movement phase; e) Comparison of the determined current phase of movement performed by the user with at least one basic phase of movement to determine the selected type of movement performed by the user; f) Signaling the control mechanisms of the exoskeleton of the upper or lower extremities to support the user by the exoskeleton during a certain current phase of movement that coincides with the basic phase of movement; e) Execution by the user of the next phase of movement, according to the selected type of movement; h) Repetition of steps c) -f) until the end of the final phase of the movement of the selected type of movement performed by the user. i) Repetition of steps b) -h) until completion of the workout.

2. The method according to claim 1, characterized in that at least one basic phase of movement performed by the user for each type of movement, when calibrating the exoskeleton of the upper or lower extremities, is determined by processing the EMG signal on based on 5-7 repetitions of each type of movement of the exoskeleton of the upper or lower extremities, performed by the user.

3. The method according to claim 1, characterized in that at least two different types of movements performed by the user, having at least one identical phase of movement, the current phase and each basic phase of movements performed by the user, are additionally determined during registration and processing of EMG- signal based on the value of the amplitude-time characteristic - the change in the tension level of active muscles during the movement phase.

4. The method according to claim 3, characterized in that the set of base phases for each type of movement performed by the user, when calibrating the exoskeleton of the upper or lower extremities, is determined during registration and processing of the EMG signal on the basis of 5-7 repetitions performed by the user at least two different types of movement having at least one identical movement phase.

5. The method according to claim 1, characterized in that when a certain phase of movement performed by the user does not coincide with the basic phase of movement, the exoskeleton performs the corresponding current basic phase of movement for the user.

6. The method of claim. 1, characterized in that the calculated and current amplitude-time characteristics are displayed on the screen for the user.