WO2023227086A1

WO2023227086A1 - Heterogeneous surface electromyography acquisition apparatus

Info

Publication number: WO2023227086A1
Application number: PCT/CN2023/096424
Authority: WO
Inventors: 刘洪海; 常辉; 杨宏宇; 刘一凡
Original assignee: 哈尔滨工业大学（深圳）
Priority date: 2022-05-26
Filing date: 2023-05-26
Publication date: 2023-11-30
Also published as: CN114795254A

Abstract

A heterogeneous surface electromyography acquisition apparatus, comprises a main control module, a power supply management module, a data transmission module, a first electromyography acquisition assembly and a second electromyography acquisition assembly. The main control module is separately in communication connection with the first electromyography acquisition assembly and the second electromyography acquisition assembly. The power supply management module supplies power. The data transmission module communicates with the main control module and communicates with a host computer. The first electromyography acquisition assembly is used for acquiring a high-density electromyographic signal and comprises a plurality of high-density electromyography acquisition modules which are connected to electrodes in a single-ended input mode. The second electromyography acquisition assembly acquires a distributed electromyographic signal and comprises distributed electromyography acquisition modules which are connected to wet electrodes in a differential input mode. The electromyography acquisition apparatus collects at least a 128 channel high-density electromyography and 8-channel distributed electromyography, the sampling frequency is 1 kHz, and the data precision is 24 bits.

Description

A heterogeneous surface electromyography collection device

Technical field

The present application relates to the technical field of human-computer interaction, and in particular to a heterogeneous surface electromyography collection device.

Background technique

Surface electromyogram (sEMG) refers to the bioelectrical signal during neuromuscular system activity recorded from the muscle surface through electrodes. Movement intention signals from the cerebral cortex are transmitted through motor neurons in the spinal cord to the muscle fibers connected by axon terminals. Then the muscle fibers produce potential changes, causing muscle contraction and generating an electric field on the surface of human soft tissue and skin. The potential difference detected in this electric field is called myoelectric signal.

The amplitude of sEMG is about 0-5mV, the main frequency band is 20-500Hz, most of it is 50-150Hz, and it is obviously weakened above 300Hz, and the signal has poor stability and strong randomness. Although the spatial resolution of this signal is not as high as that of traditional needle electromyography, it has better repeatability and a larger detection space. A large number of studies have found that surface electromyographic signals come from the electrophysiological activity of spinal alpha motor neurons, which are controlled by the brain's motor cortex. The frequency and amplitude of the generated electromyographic signal are affected by both physiological factors and measurement factors. The main physiological factors include: different muscle functional states and activity levels, which lead to different muscle fiber recruitment methods and motor unit synchronization activities; measurement Factors mainly include: muscle length, skin temperature, muscle contraction mode, signal stringing and electrode position, etc. Under standardized operations, quantitative analysis of the collected surface electromyographic signals can enable researchers to understand the subject's muscle activation pattern, muscle fatigue, muscle strength, coordination of multiple muscle groups, and the response of motor units to excitement. A series of issues such as transmission speed are widely concerned by modern scientific workers, and therefore have extremely important research significance and application value for rehabilitation medicine, sports science, basic medicine and other disciplines. Since the 1960s, people have gradually matured in the detection and processing methods of surface electromyography signals, and its application scope has become wider and wider, mainly reflected in clinical diagnosis, intelligent prosthetic limb control, functional electrical stimulation and biofeedback research, and sports scientific research. etc.

Currently, existing surface myoelectricity collection equipment is mainly divided into two types: high-density myoelectricity collection equipment and distributed myoelectricity collection equipment. High-density EMG collection equipment collects high-density EMG signals from multiple channels simultaneously through high-density electrode sheets, and distributed EMG collection equipment collects distributed EMG signals from multiple channels through multiple wet electrodes. However, the current myoelectric collection equipment cannot simultaneously collect high-density myoelectricity and distributed myoelectricity, cannot realize the expansion of myoelectricity collection module, and the cost of myoelectricity collection equipment is high.

Therefore, those skilled in the art are committed to developing a heterogeneous surface electromyography collection device. It can simultaneously collect high-density EMG and distributed EMG signals, realize the expansion of EMG acquisition modules, and reduce the cost of EMG acquisition equipment.

Application content

In view of the above-mentioned defects of the existing technology, the technical problem to be solved by this application is to simultaneously collect high-density EMG signals and distributed EMG signals, realize the expansion of the EMG acquisition module, and reduce the cost of EMG acquisition equipment.

In order to achieve the above purpose, this application provides a heterogeneous surface electromyography collection device, including a main control module, a power management module, a data transmission module, a first myoelectricity collection component and a second myoelectricity collection component.

The main control module is communicatively connected to the first myoelectric collection component and the second myoelectric collection component respectively;

The power management module is configured to provide power to the main control module, the first myoelectric collection component, and the second myoelectric collection component;

The data transmission module communicates with the main control module, and the data transmission module is configured to communicate with a host computer;

The first myoelectric acquisition component is configured to collect high-density myoelectric signals. The first myoelectric acquisition component includes multiple high-density myoelectric acquisition modules. The multiple high-density myoelectric acquisition modules adopt single-ended input. way to connect with the electrode pad;

The second myoelectric collection component is configured to collect distributed myoelectric signals. The second myoelectric collection component includes a distributed myoelectric collection module and is connected to the wet electrode in a differential input manner;

The electromyography acquisition device is configured to collect at least 128 channels of high-density electromyography and 8 channels of distributed electromyography, with a sampling frequency of 1 kHz and a data accuracy of 24 bits.

Further, the multiple high-density EMG collection modules are connected in a daisy chain manner and communicate with the main control module through SPI; the distributed EMG collection modules are connected in a daisy chain manner and communicate with the main control module through SPI. control module communication.

Further, the main control module adopts a chip with a floating-point arithmetic unit.

Further, the chip of the main control module communicates with the data transmission module through RMII.

Further, the data transmission module selects an Ethernet chip that supports 100M communication rate.

Further, the negative electrodes of the multiple high-density myoelectric collection modules are drawn out and collected at the interface to be connected to the electrode sheet. The common positive electrodes of the multiple high-density myoelectric collection modules are connected to the right leg drive circuit and lead out the electrodes. Connected to skin.

Further, the reference voltage circuits of the plurality of high-density myoelectric collection modules include voltage followers, and the voltage followers are configured to generate 0V for connection to the skin.

Further, the positive and negative electrodes of the distributed myoelectric collection module are drawn out and connected to the wet electrode through the earphone interface.

Further, the distributed myoelectric collection module and the multiple high-density myoelectric collection modules share the right leg drive circuit.

Further, each of the plurality of high-density electromyography acquisition modules has eight channels.

Further, the distributed electromyography acquisition module has eight channels.

Further, each of the high-density myoelectric collection modules is pluggable.

Further, the distributed myoelectricity collection module is pluggable.

Further, the connection between the multiple high-density electromyography acquisition modules and the main control module is a gold finger.

Further, the connection between the distributed myoelectric collection module and the main control module is a gold finger.

Further, the myoelectric collection device is configured to expand the number of channels by adding a high-density myoelectric collection module and/or the distributed myoelectric collection module.

Further, each of the plurality of high-density myoelectric collection modules and the distributed myoelectric collection module are configured to be replaceable.

Further, the electromyography collection device uses uC/OS-II operating system.

Further, the power management module generates five voltage values: 5V, 3.3V, +2.5V, -2.5V, and GND.

Further, the analog circuit and the digital circuit in the power management module are isolated.

This application designs two different collection modules: a high-density myoelectric collection module and a distributed myoelectric collection module. Each module has eight channels. Different types of acquisition modules are connected in different daisy chains and use different SPIs to communicate with the main control to achieve different configurations and relatively independent communication. The high-density EMG acquisition module uses a single-ended input method to connect to high-density electrodes to collect high-density EMG signals. The distributed EMG acquisition module uses a differential input method to connect to wet electrodes to collect distributed EMG signals to achieve high density. For the synchronous collection of myoelectric signals and distributed myoelectric signals, different combinations of myoelectric signals can be selected according to specific needs and experimental requirements. Each acquisition module can collect up to eight channels of myoelectric signals and connect to the power management module and main control module through golden fingers. The acquisition modules are all pluggable, and scalability is achieved through multiple interfaces and the modular design of the acquisition module. At the same time, it can solve the problem of high replacement costs when problems occur, and only need to replace the smallest acquisition module.

Compared with the prior art, this application has the following obvious substantive features and significant advantages:

1. Two types of collection modules are designed, the high-density myoelectric collection module and the distributed myoelectric collection module, to achieve simultaneous collection of high-density myoelectricity and distributed myoelectricity. It can simultaneously collect at least 128 channels of high-density EMG signals and 8 channels of distributed EMG signals at a frequency of 1KHz.

2. Extensible. The number of myoelectric collection channels can be expanded. The acquisition module is composed of eight channels, and the number of channels can be expanded by increasing the number of acquisition modules.

3. Low cost. Only the faulty acquisition module needs to be replaced.

The concept, specific structure and technical effects of the present application will be further described below in conjunction with the accompanying drawings to fully understand the purpose, features and effects of the present application.

Description of the drawings

Figure 1 is a functional block diagram of a heterogeneous electromyography acquisition system according to a preferred embodiment of the present application;

Figure 2 is a reference voltage circuit of a preferred embodiment of the present application;

Figure 3 is a right leg drive circuit of a preferred embodiment of the present application;

Figure 4 is a schematic diagram of the positive and negative electrode connections of the high-density electromyography acquisition module of the preferred implementation of this application.

Figure 5 is the positive and negative electrode connection method of the distributed myoelectric collection of the preferred implementation of this application.

Detailed ways

The following describes multiple preferred embodiments of the present application with reference to the accompanying drawings to make the technical content clearer and easier to understand. The present application can be embodied in many different forms of embodiments, and the protection scope of the present application is not limited to the embodiments mentioned in the text.

In the drawings, components with the same structure are denoted by the same numerals, and components with similar structures or functions are denoted by similar numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the size and thickness of each component are not limited by this application. In order to make the illustrations clearer, the thickness of components is exaggerated in some places in the drawings.

In the preferred embodiment of the present application, the main function of the heterogeneous surface electromyography acquisition device is to synchronously collect high-density surface electromyography and distributed surface electromyography from the human body, preprocess it, and transmit it to the host computer software.

As shown in Figure 1, the acquisition system can be divided into power management module, main control module, data transmission module, high-density EMG acquisition module, and distributed EMG acquisition module.

The power management module needs to supply power to the main control module, data transmission module, high-density myoelectric collection module, and distributed myoelectric collection module. It needs to generate five voltage values: 5V, 3.3V, +2.5V, -2.5V, and GND. Since analog circuits and digital circuits are involved, digital circuits involve high-speed communications (SPI, RMII), which will introduce high-frequency noise, so the analog circuits need to be isolated from the digital circuits to prevent the analog signals from being contaminated.

The main control module needs to complete the following functions: 1) control the entire device; 2) communicate with the host computer. The entire device collects at least 128 channels of high-density EMG and 8 channels of distributed EMG, with a sampling frequency of 1KHz and 24-bit data accuracy. According to calculations in (1), it is known that to complete such data communication, the transmission speed is at least 3.264Mbps.
136×1000×24＝3264000bps＝3.264Mbps (1)

All data are preprocessed and packaged. According to (2), 136,000 int data needs to be processed per second. If you need to make a digital filter on an MCU, it will involve a large number of floating-point operations, and the CPU requires at least 16 clock cycles to calculate a floating-point number, which greatly reduces its operation efficiency. You must choose a floating-point operation unit ( Floating Point Unit (FPU) chip is used as MCU.
1000×136＝136000 (2)

Finally, STM32H743 was selected as the main control chip, which communicates with the data transmission module through RMII and controls the data acquisition module through multiple sets of SPI to complete the collection, processing and transmission of myoelectric signals.

The data transmission module needs to transmit at least 400 bytes of data within 1ms. Excluding the time occupied by data collection, preprocessing, and packaging, it needs to complete the transmission work within 300us. According to (3), the calculation requires a transmission speed of at least 10.88Mbps. Taking into account the check digit and retransmission when an error occurs, a faster transmission speed is required. This task cannot be completed using Bluetooth, WIFI, etc., and the Fast Ethernet chip LAN8720A, which supports 100M communication rate, was finally selected. The protocol built when using this chip will poll every once in a while to check The current network connection status causes the STM32 computing resources to be completely occupied, making other communication and computing impossible. In order to avoid this situation, the uC/OS-II operating system is used to ensure the real-time and security of the system.
136×3333×24＝3264000bps＝10.88Mbps (3)

Generally, the EMG collection method with more than 16 channels is called high-density EMG. In this application, high-density EMG collection refers to the collection method using array-type EMG electrodes. As shown in Figure 4, the high-density electromyography acquisition module uses the ADS1299 chip to connect in a daisy chain, communicates with the main control module through SPI, and adopts a single-ended input method to lead out the negative electrodes of multiple high-density electromyography acquisition modules. , summarized to the high-density electrode interface and connected to the high-density electrode, the common positive electrode is connected to the right leg drive circuit and the lead electrode is connected to the skin, so as to avoid the collected bioelectrical signals from causing saturation of the instrumentation amplifier that amplifies the electrical signals, and Common mode interference is suppressed by adding the electromyographic data of all channels on the skin and then connecting it to the skin. But this way of using it will also bring some problems. A more serious problem is that if the design of the peripheral circuit does not better match the user's skin impedance, this part of the circuit will not only fail to suppress common mode interference, but will introduce excess noise, thus affecting the signal quality. Another is that using the built-in BIAS circuit of ADS1299 will cause the circuit power consumption to increase. Therefore, two circuits are designed to meet the needs of different users. The other circuit (reference voltage circuit, as shown in Figure 2) uses a voltage follower to generate 0V that is not subject to external interference and is connected to the skin to avoid the collected biological The electrical signal causes the instrumentation amplifier used to amplify the electrical signal to saturate.

The distributed myoelectric collection module uses the ADS1299 chip to connect in a daisy chain, communicates with the main control module through SPI, and adopts a differential input method to lead out the positive and negative electrodes of the distributed myoelectric collection module, and connects to the wet electrode through the headphone interface. Make the connection and share the right leg drive circuit with the high-density myoelectric acquisition module, as shown in Figure 3 and Figure 5. Differential input means that the electromyographic signal of a channel is obtained by the difference between the positive input and the negative input. A single-ended input is the difference between the positive or negative input and a common reference electrode. Differential input allows the EMG signals of all channels to use the same reference signal, which can save the number of electrodes.

The preferred specific embodiments of the present application are described in detail above. It should be understood that those skilled in the art can make many modifications and changes based on the concept of the present application without creative efforts. Therefore, any technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the prior art based on the concepts of this application should be within the scope of protection determined by the claims.

Claims

A heterogeneous surface electromyography collection device, including a main control module, a power management module, a data transmission module, a first myoelectricity collection component and a second myoelectricity collection component,

The main control module is communicatively connected to the first myoelectric collection component and the second myoelectric collection component respectively;

The power management module is configured to provide power to the main control module, the first myoelectric collection component, and the second myoelectric collection component;

The data transmission module communicates with the main control module, and the data transmission module is configured to communicate with a host computer;

The first myoelectric acquisition component is configured to collect high-density myoelectric signals. The first myoelectric acquisition component includes multiple high-density myoelectric acquisition modules. The multiple high-density myoelectric acquisition modules adopt single-ended input. way to connect with the electrode pad;

The second myoelectric collection component is configured to collect distributed myoelectric signals. The second myoelectric collection component includes a distributed myoelectric collection module and is connected to the wet electrode in a differential input manner;

The electromyography acquisition device is configured to collect at least 128 channels of high-density electromyography and 8 channels of distributed electromyography, with a sampling frequency of 1 kHz and a data accuracy of 24 bits.
The heterogeneous surface electromyography acquisition device according to claim 1, wherein the multiple high-density electromyography acquisition modules are connected in a daisy chain manner and communicate with the main control module through SPI; the distributed electromyography acquisition module The modules are connected in a daisy chain and communicate with the main control module through SPI.
The heterogeneous surface electromyography acquisition device according to claim 1, wherein the main control module adopts a chip with a floating point number operation unit.
The heterogeneous surface electromyography collection device according to claim 3, wherein the chip of the main control module communicates with the data transmission module through RMII.
The heterogeneous surface electromyography collection device according to claim 1, wherein the data transmission module selects an Ethernet chip that supports 100M communication rate.
The heterogeneous surface electromyography collection device according to claim 2, wherein the negative electrodes of the plurality of high-density electromyography collection modules are collected at the interface and connected to the electrode sheet, and the plurality of high-density electromyography collection modules are connected to the electrode sheet. The common positive electrode of the acquisition module is connected to the right leg drive circuit and the lead electrode is connected to the skin.
The heterogeneous surface electromyography collection device according to claim 6, wherein the reference voltage circuit of the plurality of high-density electromyography collection modules includes a voltage follower, the voltage follower is configured to generate 0V connected to the skin .
The heterogeneous surface electromyography collection device according to claim 2, wherein the positive and negative electrodes of the distributed myoelectricity collection module are drawn out and connected to the wet electrode through an earphone interface.
The heterogeneous surface electromyography collection device according to claim 6, wherein the distributed electromyography collection module The right leg driving circuit is shared with the multiple high-density electromyography acquisition modules.
The heterogeneous surface electromyography collection device according to claim 1, wherein each of the plurality of high-density electromyography collection modules has eight channels.
The heterogeneous surface electromyography collection device according to claim 1, wherein the distributed electromyography collection module has eight channels.
The heterogeneous surface electromyography collection device according to claim 1, wherein each of the high-density electromyography collection modules is pluggable.
The heterogeneous surface electromyography collection device according to claim 1, wherein the distributed electromyography collection module is pluggable.
The heterogeneous surface electromyography collection device according to claim 12, wherein the connection between the plurality of high-density electromyography collection modules and the main control module is a gold finger.
The heterogeneous surface electromyography collection device according to claim 13, wherein the connection between the distributed electromyography collection module and the main control module is a gold finger.
The heterogeneous surface myoelectric collection device according to claim 1, wherein the myoelectric collection device is configured to increase the number of channels by adding high-density myoelectric collection modules and/or the distributed myoelectric collection modules. Extension.
The heterogeneous surface electromyography collection device according to claim 1, wherein each of the plurality of high-density electromyography collection modules and the distributed electromyography collection module are configured to be replaceable.
The heterogeneous surface electromyography collection device according to claim 1, wherein the electromyography collection device uses a uC/OS-II operating system.
The heterogeneous surface electromyography collection device according to claim 1, wherein the power management module generates five voltage values: 5V, 3.3V, +2.5V, -2.5V, and GND.
The heterogeneous surface electromyography collection device according to claim 19, wherein the analog circuit and the digital circuit in the power management module are isolated.