Neuromuscular stimulation system with myoelectricity feedback function

Abstract

The invention relates to a neuromuscular stimulation system with a myoelectricity feedback function. The neuromuscular stimulation system comprises a power supply module used for supplying power to the whole system; the surface myoelectricity module is used for sensing the neuromuscular state of the stimulated part and serving as a reference of a driving signal of the muscle stimulation module; the muscle stimulation module is used for outputting electric stimulation pulses with appropriate and variable frequency and pulse width; and the integrated controller module is used for acquiring myoelectricity information sensed by the surface myoelectricity module, performing noise reduction processing and feature extraction to obtain a driving control signal of the muscle stimulation module, generating reference voltage with corresponding amplitude according to the magnitude of the driving control signal, acting on the muscle stimulation module, and further controlling and adjusting stimulation parameters output by the muscle stimulation module. According to the neuromuscular stimulation system with the myoelectricity feedback function, output is safe and reliable, operation is easy, muscle force information of a stimulated part can be fed back in real time, the size of stimulation parameters can be adjusted in a self-adaptive mode according to conditions, and the stimulation efficiency is effectively improved.

Description

Technical Field

[0001] The invention relates to the field of rehabilitation equipment, in particular to a neuromuscular stimulation system with myoelectric feedback function. Background Art

[0002] Currently, most neuromuscular stimulation systems on the market use constant voltage stimulation and can usually only generate electrical stimulation pulses in a single direction. During long-term use, this type of neuromuscular stimulation system will cause corresponding changes in the stimulation current acting on the muscle due to changes in skin impedance, and cannot guarantee the consistency of muscle contraction. At the same time, a single stimulation pulse will cause patients to have habitual adaptation problems when receiving stimulation, which greatly reduces the effectiveness of neuromuscular stimulation. Summary of the invention

[0003] In view of the existing problems, the present invention provides a neuromuscular stimulation system with electromyographic feedback function, which can adaptively adjust the electrostimulation parameters according to the situation to meet the needs of neuromuscular stimulation.

[0004] The neuromuscular stimulation system with myoelectric feedback function comprises: a power supply module and a surface electromyography module, a muscle stimulation module and an integrated controller module respectively connected thereto, wherein the integrated controller module is composed of an embedded microcontroller minimum system.

[0005] The power supply module includes a lithium battery with a voltage of 12V and a power of 36W and four groups of DC-DC circuits connected thereto respectively, one group of DC-DC circuits is a boost DC-DC circuit connected to the muscle stimulation module, and the other three groups of DC-DC circuits are buck DC-DC circuits, wherein the first buck DC-DC circuit and the second buck DC-DC circuit are both connected to the surface electromyography module, and the third buck DC-DC circuit is connected to the integrated controller module, the boost DC-DC circuit outputs a +80V voltage, the first buck DC-DC circuit outputs a +5V voltage, the second buck DC-DC circuit outputs a -5V voltage, and the third buck DC-DC circuit outputs a +3.3V voltage.

[0006] The surface electromyography module includes a preamplifier circuit, a filter conditioning circuit, a hierarchical amplifier circuit and a voltage boost circuit which are respectively connected to the power module and connected in sequence, the voltage boost circuit is connected to the integrated controller module, and also includes an electromyography collection electrode connected to the preamplifier circuit, wherein:

[0007] The electromyography acquisition electrode is composed of a disposable silver chloride electrode sheet containing conductive gel and a metal electrode wire connected to the electrode sheet;

[0008] The filtering and conditioning circuit comprises a high-pass filter, a low-pass filter and a double-T type power frequency trap circuit which are connected in sequence.

[0009] The muscle stimulation module includes: a high-voltage power supply interface, a photoelectric isolation circuit and a biphasic stimulation constant current source circuit connected in sequence, and also includes a neuromuscular stimulation electrode arranged between the photoelectric isolation circuit and the biphasic stimulation constant current source circuit. The high-voltage power supply interface is connected to the power supply module, and the photoelectric isolation circuit and the biphasic stimulation constant current source circuit are both connected to the integrated controller module.

[0010] The biphasic stimulation constant current source circuit is composed of a group of voltage-controlled constant current source circuits with the same circuit structure and opposite output current directions. The voltage-controlled constant current source circuit includes an operational amplifier U1A, a field effect transistor Q1 and two resistors R1 and R2, wherein:

[0011] The operational amplifier U1A has a non-inverting input terminal connected to the integrated controller module, an inverting input terminal connected to ground via a resistor R2, an output terminal connected to the gate of the field effect transistor Q1 via a resistor R1, a source of the field effect transistor Q1 connected to ground via a resistor R2, and a drain connected to a neuromuscular stimulation electrode.

[0012] The neuromuscular stimulation method with electromyographic feedback function comprises the following steps:

[0013] The power module supplies power to the surface electromyography module, the muscle stimulation module and the integrated controller module;

[0014] The surface electromyography module obtains the neuromuscular state signal of the stimulation site through the electromyography acquisition electrode, and processes it to generate electromyography information;

[0015] The muscle stimulation module outputs electrical stimulation pulses with varying frequencies through the neuromuscular stimulation electrodes and acts on the affected area;

[0016] The integrated controller module performs digital noise reduction processing on the electromyographic information, obtains a drive control signal and sends it to the muscle stimulation module, and generates a reference voltage according to the drive control signal and sends it to the muscle stimulation module to adjust the stimulation parameters output by the muscle stimulation module.

[0017] The surface electromyography module performs the following steps:

[0018] The electromyography acquisition electrode obtains the neuromuscular status signal of the stimulation site;

[0019] The preamplifier circuit increases the input impedance through the operational amplifier and performs the first voltage amplification processing on the neuromuscular state signal;

[0020] The filter conditioning circuit filters out the noise in the signal after the first amplification;

[0021] The hierarchical amplifier circuit performs secondary voltage amplification processing on the filtered signal by adjusting the variable resistor;

[0022] The voltage boosting circuit superimposes a constant voltage on the signal after secondary amplification, adjusts the output voltage of the surface electromyography module, and obtains electromyography information.

[0023] The muscle stimulation module performs the following steps:

[0024] The neuromuscular stimulation electrodes output electrical stimulation pulses;

[0025] The high-voltage power supply interface receives the voltage from the connected power module;

[0026] The photoelectric isolation circuit controls the on and off of the photoelectric coupler according to the PWM signal sent by the integrated controller module, thereby controlling whether the muscle stimulation module works;

[0027] The biphasic stimulation constant current source circuit processes the reference voltage output by the integrated controller module to generate a biphasic electrical stimulation pulse.

[0028] The sampling resistor R 2 The resistance value is fixed, so that the current of the biphasic electrical stimulation pulse does not change with the change of the load impedance at the contact point between the electromyography acquisition electrode and the skin. By adjusting the reference voltage output by the integrated controller module, the current of the biphasic electrical stimulation pulse output by the biphasic stimulation constant current source circuit can be adjusted.

[0029] The integrated controller module performs the following steps:

[0030] The electromyographic information of the surface electromyographic module is obtained through the internal integrated A / D converter, and the digital filtering method is used to perform noise reduction processing to determine its amplitude, start time and duration. The electromyographic information is used as a reference to control the muscle stimulation module through the D / A converter and the output PWM signal so that the electrical stimulation pulse has the same waveform polarity and amplitude envelope as the electromyographic information.

[0031] The present invention has the following beneficial effects and advantages:

[0032] The present invention provides a neuromuscular stimulation system with electromyographic feedback function. The system adopts a constant current method for electrical stimulation. Compared with a constant voltage method, the system can keep the muscles consistent during repeated contractions and can greatly reduce the impact of changes in skin resistance. At the same time, the system can provide real-time feedback on the muscle strength information of the stimulated part and adaptively adjust the stimulation parameters according to the situation, which effectively improves the efficiency of the stimulation and reduces the discomfort of the neuromuscular stimulation system during long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural block diagram of a neuromuscular stimulation system with myoelectric feedback function of the present invention;

[0034] Figure 2 It is a system composition block diagram of the surface electromyography module of the present invention;

[0035] Figure 3 It is a working mode diagram of the biphasic stimulation constant current source circuit of the present invention;

[0036] Figure 4 It is a schematic diagram of a biphasic stimulation constant current source closed-loop feedback circuit of the present invention. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the invention, so the present invention is not limited by the specific implementation disclosed below.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0040] like Figure 1 Shown is a structural block diagram of a neuromuscular stimulation system with myoelectric feedback function according to the present invention.

[0041] A neuromuscular stimulation system with electromyographic feedback function, comprising the following parts:

[0042] Power module 1, surface electromyography module 2, muscle stimulation module 3, integrated controller module 4. The power module 1 is respectively connected to the surface electromyography module 2, the muscle stimulation module 3, and the integrated controller module 4, and supplies power to them; the surface electromyography module 2 is used to sense the neuromuscular state of the stimulation site, and serves as a driving excitation signal for the muscle stimulation module 3; the muscle stimulation module 3 is used to output electrical stimulation pulses with a suitable and variable frequency pulse width, and act on the affected site; the integrated controller module 4 is connected to the surface electromyography module 2 and the muscle stimulation module 3, and is used to collect the electromyography information sensed by the surface electromyography module 2 and perform digital noise reduction processing on it, so as to obtain a stable and effective driving control signal to act on the muscle stimulation module 3, and can generate a reference voltage of corresponding amplitude according to the size of the driving control signal to act on the muscle stimulation module 3, so as to adjust the stimulation parameters output by the muscle stimulation module 3.

[0043] The power module 1 is powered by a 12V 36W lithium battery and includes four groups of DC-DC circuits. One group is a boost circuit acting on the muscle stimulation module 3, which is composed of a DC-DC power module HRB1280 and is used to provide a +80V high voltage for generating electrical stimulation pulses; the other three groups are step-down circuits, which stably output +5V, +3.3V and -5V DC voltages respectively, wherein the +5V voltage and -5V voltage act on the surface electromyography module 2 to provide voltage for the bipolar power supply chip in the system, and the -5V voltage is generated by the +5V voltage through a reverse charge pump converter; the +3.3V voltage acts on the integrated controller module 4 to power the module.

[0044] like Figure 2 Shown is a system composition block diagram of the surface electromyography module of the present invention.

[0045] The surface electromyography module 2 is composed of five parts: electromyography acquisition electrode 2-1, preamplifier circuit 2-2, filter conditioning circuit 2-3, graded amplifier circuit 2-4, and potential raising circuit 2-5. Among them, the electromyography acquisition electrode 2-1 is composed of a disposable silver chloride electrode sheet containing conductive gel and a metal electrode wire connected to the electrode sheet; the preamplifier circuit 2-2 is composed of an instrument operational amplifier with low noise and high common mode rejection ratio, which is used to improve the input impedance of the system; the filter conditioning circuit 2-3 is composed of three parts, namely: a second-order active Butterworth high-pass filter with a cut-off frequency of 16Hz, a second-order active Butterworth low-pass filter with a cut-off frequency of 482Hz, and a double-T type power frequency trap circuit with a cut-off frequency of 50Hz, which is used to reduce the introduction of external environment Noise interference; the graded amplification circuit 2-4 is used to offset the signal fluctuations caused by skin conditions, changes in electrode position, etc., and the gain of the voltage amplification is changed by adjusting the variable resistor, thereby amplifying the collected surface electromyography signal to a suitable size to avoid voltage saturation at the signal output end; the potential raising circuit 2-5 is used to adjust the electromyography signal output voltage to between 0-3.3V so that the integrated controller module 4 can perform A / D conversion, and the method is to superimpose a constant voltage on the signal output end to offset the influence of the negative voltage generated by the alternating characteristics of the surface electromyography signal.

[0046] The muscle stimulation module 3 is composed of a neuromuscular stimulation electrode 3-1, a high-voltage power supply interface 3-2, a photoelectric isolation circuit 3-3, and a biphasic stimulation constant current source circuit 3-4. Among them, the neuromuscular stimulation electrode 3-1 directly acts on the surface of human muscles and is responsible for outputting electrical stimulation pulses; the high-voltage power supply interface 3-2 adopts the XT30 standard package and an external insulating protective shell, which is used to connect the +80V high voltage generated by the power module 1; the photoelectric isolation circuit 3-3 is realized by a photoelectric coupler, and the coupling and transmission of electrical signals are realized through optical signals as a medium, completing the isolation of the high-voltage circuit and ensuring the safety of the system; at the same time, the input end of the photoelectric coupler is connected to the integrated controller module 4, which facilitates the program control of the system, and the on-off status of the module can be controlled by the PWM signal; the biphasic stimulation constant current source circuit 3-4 is composed of a group of voltage-controlled constant current source circuits with the same circuit structure and opposite output current directions, and its working mode is as follows Figure 3 When the constant current source 2 is working, it can generate a positive current I+; when the constant current source 1 is working, it can generate a negative current I-, thereby forming a biphasic stimulation pulse.

[0047] like Figure 4 Shown is a schematic diagram of a biphasic stimulation constant current source closed-loop feedback circuit of the present invention.

[0048] U1A is an operational amplifier, R 2 is the sampling resistor, RL is the load resistor, and V is generated by the junction between the neuromuscular stimulation electrode 3-1 and the skin. ref is the reference voltage output by the integrated controller module 4 through the D / A converter, V cc The +80V high voltage is output by the power module 1 through the optoelectronic isolation circuit; the field effect transistor Q1 should be an N-channel enhancement type; the operational amplifier U1A can be based on the input V ref The size of the field effect tube is used to control the conduction and generate the corresponding output current. According to the virtual short and virtual open principle of the operational amplifier, the voltage acting on the sampling resistor R 2 The voltage of the sampling resistor is equal to the reference voltage, so the current I flowing through the sampling resistor is d =V ref / R 2 According to the characteristics of the field effect tube, the source current and drain current of the field effect tube are equal, so the current through the load resistor RL will always be equal to the ratio of the reference voltage to the sampling resistor, so the system output current does not change with the resistance of the load resistor. When working, you can first fix the resistance of the sampling resistor, and then adjust the voltage value V output by the D / A converter. ref To adjust the output current of the neuromuscular stimulator.

[0049] The integrated controller module 4 is composed of an embedded microcontroller minimum system. It collects the electromyographic information sensed by the surface electromyographic module 2 through an internally integrated high-precision A / D converter, and then reduces the noise of the collected electromyographic signal through a digital filtering method, and uses the level information of the obtained high-quality electromyographic data as the driving timing of the muscle stimulation module 3. The D / A converter controls the output of electric stimulation pulses with appropriate intensity, so that the electric stimulation pulses and the electromyographic signals at the stimulation site have the same waveform polarity and amplitude envelope. It should be noted that the timing of the electric stimulation pulses must maintain a non-overlapping relationship with the timing of the electromyographic signal; at the same time, the integrated controller module 4 can also control the photoelectric isolation circuit in the muscle stimulation module 3 by adjusting the output PWM signal, so as to adjust the on and off of the stimulation pulses and the output frequency.

Claims

1. A neuromuscular stimulation system with electromyographic feedback function, characterized in that: include: A power supply module and a surface electromyography module, a muscle stimulation module and an integrated controller module respectively connected thereto, wherein the integrated controller module is composed of an embedded microcontroller minimum system.

2. The neuromuscular stimulation system with myoelectric feedback function according to claim 1, characterized in that: The power supply module includes a lithium battery with a voltage of 12V and a power of 36W and four groups of DC-DC circuits connected thereto respectively, one group of DC-DC circuits is a boost DC-DC circuit connected to the muscle stimulation module, and the other three groups of DC-DC circuits are buck DC-DC circuits, wherein the first buck DC-DC circuit and the second buck DC-DC circuit are both connected to the surface electromyography module, and the third buck DC-DC circuit is connected to the integrated controller module, the boost DC-DC circuit outputs a +80V voltage, the first buck DC-DC circuit outputs a +5V voltage, the second buck DC-DC circuit outputs a -5V voltage, and the third buck DC-DC circuit outputs a +3.3V voltage.

3. The neuromuscular stimulation system with myoelectric feedback function according to claim 1, characterized in that: The surface electromyography module includes a preamplifier circuit, a filter conditioning circuit, a hierarchical amplifier circuit and a voltage boost circuit which are respectively connected to the power module and connected in sequence, the voltage boost circuit is connected to the integrated controller module, and also includes an electromyography collection electrode connected to the preamplifier circuit, wherein: The electromyography acquisition electrode is composed of a disposable silver chloride electrode sheet containing conductive gel and a metal electrode wire connected to the electrode sheet; The filtering and conditioning circuit comprises a high-pass filter, a low-pass filter and a double-T type power frequency trap circuit which are connected in sequence.

4. The neuromuscular stimulation system with myoelectric feedback function according to claim 1, characterized in that: The muscle stimulation module includes: a high-voltage power supply interface, a photoelectric isolation circuit and a biphasic stimulation constant current source circuit connected in sequence, and also includes a neuromuscular stimulation electrode arranged between the photoelectric isolation circuit and the biphasic stimulation constant current source circuit. The high-voltage power supply interface is connected to the power supply module, and the photoelectric isolation circuit and the biphasic stimulation constant current source circuit are both connected to the integrated controller module.

5. The neuromuscular stimulation system with myoelectric feedback function according to claim 4, characterized in that: The biphasic stimulation constant current source circuit is composed of a group of voltage-controlled constant current source circuits with the same circuit structure and opposite output current directions. The voltage-controlled constant current source circuit includes an operational amplifier U1A, a field effect transistor Q1 and two resistors R1 and R2, wherein: The operational amplifier U1A has a non-inverting input terminal connected to the integrated controller module, an inverting input terminal connected to ground via a resistor R2, an output terminal connected to the gate of the field effect transistor Q1 via a resistor R1, a source of the field effect transistor Q1 connected to ground via a resistor R2, and a drain connected to a neuromuscular stimulation electrode.

6. A neuromuscular stimulation method with electromyographic feedback function, characterized in that: The following steps are involved: The power module supplies power to the surface electromyography module, the muscle stimulation module and the integrated controller module; The surface electromyography module obtains the neuromuscular state signal of the stimulation site through the electromyography acquisition electrode, and processes it to generate electromyography information; The muscle stimulation module outputs electrical stimulation pulses with varying frequencies through the neuromuscular stimulation electrodes and acts on the affected area; The integrated controller module performs digital noise reduction processing on the electromyographic information, obtains a drive control signal and sends it to the muscle stimulation module, and generates a reference voltage according to the drive control signal and sends it to the muscle stimulation module to adjust the stimulation parameters output by the muscle stimulation module.

7. The neuromuscular stimulation method with myoelectric feedback function according to claim 6, characterized in that: The surface electromyography module performs the following steps: The electromyography acquisition electrode obtains the neuromuscular status signal of the stimulation site; The preamplifier circuit increases the input impedance through the operational amplifier and performs the first voltage amplification processing on the neuromuscular state signal; The filter conditioning circuit filters out the noise in the signal after the first amplification; The hierarchical amplifier circuit performs secondary voltage amplification processing on the filtered signal by adjusting the variable resistor; The voltage boosting circuit superimposes a constant voltage on the signal after secondary amplification, adjusts the output voltage of the surface electromyography module, and obtains electromyography information.

8. The neuromuscular stimulation method with myoelectric feedback function according to claim 6, characterized in that: The muscle stimulation module performs the following steps: The neuromuscular stimulation electrodes output electrical stimulation pulses; The high-voltage power supply interface receives the voltage from the connected power module; The photoelectric isolation circuit controls the on and off of the photoelectric coupler according to the PWM signal sent by the integrated controller module, thereby controlling whether the muscle stimulation module works; The biphasic stimulation constant current source circuit processes the reference voltage output by the integrated controller module to generate a biphasic electrical stimulation pulse.

9. The neuromuscular stimulation method with myoelectric feedback function according to claim 8, characterized in that: The resistance value of the sampling resistor R2 in the muscle stimulation module is fixed so that the current of the biphasic electrical stimulation pulse does not change with the change of the load impedance at the contact point between the electromyography acquisition electrode and the skin. By adjusting the reference voltage output by the integrated controller module, the current of the biphasic electrical stimulation pulse output by the biphasic stimulation constant current source circuit can be adjusted.

10. The neuromuscular stimulation method with myoelectric feedback function according to claim 6, characterized in that: The integrated controller module performs the following steps: The electromyographic information of the surface electromyographic module is obtained through the internal integrated A / D converter, and the digital filtering method is used to perform noise reduction processing to determine its amplitude, start time and duration. The electromyographic information is used as a reference to control the muscle stimulation module through the D / A converter and the output PWM signal so that the electrical stimulation pulse has the same waveform polarity and amplitude envelope as the electromyographic information.

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