阅读说明：本技术 一种肌肉动态收缩的运动单元提取方法 (Muscle dynamic contraction movement unit extraction method ) 是由 何金保 安鹏 胡庆波 骆再飞 于 2019-09-11 设计创作，主要内容包括：本发明提供一种肌肉动态收缩的运动单元提取方法,首先同时采集多通道表面肌电信号和肌肉力信号,然后根据肌肉动态收缩时肌肉力的增加和减小,将多通道表面肌电信号进行分段,最后设计肌肉动态收缩函数,提取肌肉运动单元。由于肌肉运动单元发放受到肌肉力影响较大,所以肌肉动态收缩函数中引入肌肉力变化斜率,有效提高了运动单元提取的精确性。本发明实现简单,满足实际应用的需要。(The invention provides a method for extracting a muscle dynamic contraction movement unit, which comprises the steps of simultaneously acquiring a multi-channel surface electromyographic signal and a muscle force signal, segmenting the multi-channel surface electromyographic signal according to the increase and decrease of the muscle force during the dynamic contraction of the muscle, designing a muscle dynamic contraction function, and extracting the muscle movement unit. Because the muscle movement unit is greatly influenced by muscle force, the muscle force change slope is introduced into the muscle dynamic contraction function, and the accuracy of the movement unit extraction is effectively improved. The invention is simple to realize and meets the requirement of practical application.)

1. a method for extracting a motion unit of dynamic contraction of muscles is characterized by comprising the following steps:

Collecting multichannel surface electromyographic signals under dynamic muscle contraction, filtering the signals, weakening interference and simultaneously recording the change of muscle force;

Segmenting the surface electromyographic signals according to monotone increase and monotone decrease changes of the muscle force, and fitting to obtain corresponding change slopes of each segment of muscle force;

Step three, calculating an inverse matrix of a signal cross-correlation matrix aiming at each section of surface myoelectric signals;

Step four, calculating a muscle dynamic contraction function of each section of surface muscle electric signal, obtaining a distribution sequence according to the signal correlation, wherein a calculation formula of a distribution sequence xi (n) is as follows:

ξ(n)＝D^T(n)C^-1y

Where D (n) is the muscle dynamic contraction function, T denotes transposition, C^-1Is the inverse matrix of the signal cross-correlation matrix, y is the segmented signal, n is the signal corresponding time;

and fifthly, repeating each section of surface myoelectric signals, calculating issuing sequences, classifying and sorting all issuing sequences, eliminating repeated and unreasonable issuing moments and optimizing results.

2. the method for extracting motor unit of dynamic muscle contraction according to claim 1, wherein the dynamic muscle contraction function D (n) in step four is designed according to the increase or decrease of the force signal, and considering the influence of the muscle force, the specific form of D (n) is as follows:

Where k is a constant, f is the slope of the muscle force change, y is the segment signal, and n is the signal's corresponding time.

Technical Field

The invention relates to a method for extracting a motion unit of dynamic muscle contraction.

Background

surface electromyogram (surface EMG) signals are detected from the body surface of a human body by using surface electrodes, and clinically, the functional state of neuromuscular can be known more comprehensively through multi-channel sEMG. At present, the sEMG signal analysis and processing mainly aims at the surface electromyogram signals of static muscle contraction, the research on dynamic muscle contraction is very few, and the invention provides a Motor Unit (MU) extraction method of dynamic muscle contraction aiming at the dynamic muscle contraction.

A multichannel sEMG signal decomposition method researched by scholars at home and abroad mainly comprises the following steps: a K-means clustering algorithm, a template matching method, an Artificial Neural Network (ANN) algorithm, a real-time linear aliasing blind signal separation algorithm, an independent component analysis and reduction (ICA), a convolution kernel compensation algorithm and the like. However, these methods have a good effect on static muscle contraction, and are difficult to process dynamic muscle contraction, so that the multi-channel surface electromyographic signal processing is still in an exploration stage, which is one of the difficulties in the field of electromyographic research.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a method for extracting a motor unit in which a muscle contracts dynamically, comprising the steps of:

collecting multichannel surface electromyographic signals under dynamic muscle contraction, filtering the signals, weakening interference and simultaneously recording the change of muscle force;

Segmenting the surface electromyographic signals according to monotone increase and monotone decrease changes of the muscle force, and fitting to obtain corresponding change slopes of each segment of muscle force;

Step three, calculating an inverse matrix of a signal cross-correlation matrix aiming at each section of surface myoelectric signals;

step four, calculating a muscle dynamic contraction function of each section of surface muscle electric signal, obtaining a distribution sequence according to the signal correlation, wherein a calculation formula of a distribution sequence xi (n) is as follows:

ξ(n)＝D^T(n)C^-1y

where D (n) is the muscle dynamic contraction function, T denotes transposition, C^-1Is the inverse matrix of the signal cross-correlation matrix, y is the segmented signal, n is the signal corresponding time;

And fifthly, repeating each section of surface myoelectric signals, calculating issuing sequences, classifying and sorting all issuing sequences, eliminating repeated and unreasonable issuing moments and optimizing results.

the optimization measures comprise:

the muscle dynamic contraction function D (n) in the fourth step is designed according to the increase or decrease of the force signal, and the influence of the muscle force is considered, and the specific form of D (n) is as follows:

Where k is a constant, f is the slope of the muscle force change, y is the segment signal, and n is the signal's corresponding time.

compared with the prior art, the invention provides the motion unit extraction method for the dynamic muscle contraction, which segments the multichannel surface electromyographic signals according to the increase and decrease of the muscle force during the dynamic muscle contraction, designs the dynamic muscle contraction function and effectively solves the influence of the dynamic muscle contraction. Because the muscle movement unit is greatly influenced by muscle force, the muscle force change slope is introduced into the muscle dynamic contraction function, and the accuracy of the movement unit extraction is effectively improved. Meanwhile, the muscle force change slope is obtained by adopting a fitting method, so that the non-linear change condition of the muscle force can be processed.

drawings

FIG. 1 is a flow chart of the present invention.

FIG. 2 is a schematic diagram of a slope fit of a change in muscle force according to an embodiment of the invention.

Detailed Description

the present invention is further described in detail below with reference to the accompanying drawings, and can be easily implemented by those skilled in the art from the disclosure of the present specification.

Fig. 1 shows a flow chart of the present invention. A method for extracting a motion unit of dynamic contraction of muscles is characterized by comprising the following steps:

collecting multichannel surface electromyographic signals under dynamic muscle contraction, filtering the signals, weakening interference and recording the change of muscle force. Because the sEMG signal contains various interference signals, the preprocessing firstly needs to adopt a band-pass filter, reserves signals of a frequency range of 10 Hz-500 Hz, and then adopts a notch filter to filter 50Hz power frequency interference.

and step two, segmenting the surface electromyographic signals according to the monotone increase and monotone decrease changes of the muscle force, and fitting to obtain the corresponding change slope of each segment of the muscle force. The fitting of the slope of the change of the muscle force is shown in fig. 2, wherein the dotted line is the muscle force signal, and the solid line is the straight line of the fitted force slope, which is required to reflect the trend of the change of the force.

And step three, calculating an inverse matrix of the signal cross-correlation matrix aiming at each section of the surface myoelectric signals. Firstly, a cross-correlation matrix and a cross-correlation matrix inverse matrix of the multi-channel signal are calculated, wherein the cross-correlation matrix is expressed as:

C＝E(S(n)S^T(n))

where n is the sampling instant, S (n) is the multichannel signal at the nth sampling instant, S^T(n) is the multichannel signal transposition for the nth sampling instant, E (-) is the number order expectation, the inverse C of the cross-correlation matrix is calculated^-1I.e. by

C-¹＝[E(S(n)S^T(n))]^-1

Step four, calculating a muscle dynamic contraction function of each section of surface muscle electric signal, obtaining a distribution sequence according to the signal correlation, wherein a calculation formula of a distribution sequence xi (n) is as follows:

ξ(n)＝D^T(n)C^-1y

where D (n) is the muscle dynamic contraction function, T denotes transposition, C^-1Is the inverse of the signal cross-correlation matrix, y is the segmented signal, and n is the signal corresponding time. The muscle dynamic contraction function D (n) is designed according to the increase or decrease of the force signal, and the influence of the muscle force is considered, and the specific form of D (n) is as follows:

Where k is a constant, f is the slope of the muscle force change, y is the segment signal, and n is the signal's corresponding time.

And fifthly, repeating each section of surface myoelectric signals, calculating issuing sequences, classifying and sorting all issuing sequences, eliminating repeated and unreasonable issuing moments and optimizing results. Unreasonable issuing refers to that the issuing time is less than the time of 15 millisecond interval, and the rejecting is needed.

In summary, the invention provides a method for extracting a motion unit of dynamic muscle contraction, which segments a multichannel surface electromyographic signal according to increase and decrease of muscle force during dynamic muscle contraction, designs a dynamic muscle contraction function, and effectively solves the influence of dynamic muscle contraction. Because the muscle movement unit is greatly influenced by muscle force, the muscle force change slope is introduced into the muscle dynamic contraction function, and the accuracy of the movement unit extraction is effectively improved. Meanwhile, the muscle force change slope is obtained by adopting a fitting method, so that the non-linear change condition of the muscle force can be processed. The invention is simple to realize and meets the requirement of practical application.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.