CN101856284B - Myoelectric prosthetic hand control method with real-time speed regulating function - Google Patents

Abstract

The invention relates to a myoelectric prosthetic hand control method with a real-time speed regulating function; an EMG signal pickup electrode is arranged on human epidermis; the EMG signal of the electrode enters a signal pre-processing circuit after being amplified by a preamplifier circuit; the signal output by the pre-processing circuit enters a self-gain circuit; after gain and automatic regulation, the signal enters an MSP430 microprocessor through an A/D conversion circuit; the microprocessor outputs a duty cycle PWM signal to a prosthetic hand driving circuit after determining the duty cycle of the PWM signal so as to realize the real-time regulation to the speed of a prosthetic hand, achieve stable effect and bring more convenience for a user.

Description

A kind of myoelectric prosthetic hand control method with real-time speed regulating function

Technical field

The present invention relates to a kind of electronic control method, particularly a kind of myoelectric prosthetic hand control method with real-time speed regulating function.

Background technology

Electromyographic signal (Electromyogram, the electro-physiological signals that produces when EMG) being exactly muscular movement.(Surface Electromyogram SEMG) is meant the electromyographic signal that collects at skin surface to surface electromyogram signal, is human body shallow-layer muscle and neuromotor synthesis result.Its main feature has: the one, and signal amplitude is little.Usually at tens microvolts.The 2nd, signal frequency is positioned at low-frequency range (10Hz-500Hz).Though the amplitude of electromyographic signal is very little, the abundant information that it comprises, these information comprise action pattern that staff sends, speed of action size etc.Show that through expert of the art's years of researches electromyographic signal is the current optimal control information source of doing evil through another person.

At present, home-made electromyographic signal is done evil through another person, and has the uncontrollable shortcoming of speed of action.Be embodied in, give when doing evil through another person user, do evil through another person to hold fast according to the user needs and hold together to catch object when others throws an object; On the contrary, the prosthetic wearing person to grab one soft when grabbing bad object (egg, steamed bread) easily, do evil through another person and can not slowly hold and hold together to pick up object according to the wish of user.Above shortcoming has brought very big inconvenience for the user of doing evil through another person.Therefore, realizing that the ratio of the speed of doing evil through another person is regulated, is that current homemade doing evil through another person needs the problem of solution.

Summary of the invention

The present invention be directed to does evil through another person now exists the uncontrollable problem of speed of action, has proposed a kind of myoelectric prosthetic hand control method with real-time speed regulating function, realizes real-time regulated, brings bigger facility to user.

Technical scheme of the present invention is: a kind of myoelectric prosthetic hand control method with real-time speed regulating function specifically comprises the steps:

1) the electromyographic signal pickoff electrode is close to human epidermal, is used for the introducing of human body electromyographic signal;

2) electromyographic signal of being introduced by electrode is amplified through pre-amplification circuit, and signal gets into the next stage signal pre-processing circuit then; Carrying out LPF, high-pass filtering and 50Hz notch by pre-process circuit handles; The signal of handling gets into from gain circuitry, accomplishes Gain Automatic adjusting, then; Signal is changed through A/D, gets into the MSP430 microprocessor;

3) microprocessor carries out confirming of pwm signal dutycycle: the first step is to adopt the electromyographic signal intensity of averaging, and uses x _iThe first sampled point electromyographic signal intensity of representing i group sampled point, I group sampled point myoelectricity intensity after expression is averaged, concrete computing formula:

Last group sampled point to being positioned at the sampling queue afterbody does not carry out mean value computation, directly uses the average of its sampled point of last group, replaces last group electromyographic signal average; Second step was according to the electromyographic signal intensity that calculates, and calculated the pwm signal dutycycle, computing formula: η representes the dutycycle of pwm signal,

Represent i group electromyographic signal average,

One group of sampled point average that electromyographic signal intensity is maximum, The generation threshold value of expression electromyographic signal;

4) back dutycycle pwm signal artificial hand controlled drive circuit is calculated in microprocessor output, realizes doing evil through another person speed regulation.

Beneficial effect of the present invention is: the present invention has the myoelectric prosthetic hand control method of real-time speed regulating function, realizes the speed of doing evil through another person is carried out real-time regulated, effect stability.

Description of drawings

Fig. 1 has the myoelectric prosthetic hand control method work sketch map of real-time speed regulating function for the present invention.

The specific embodiment

Myoelectric prosthetic hand control method work sketch map with proportionality velocity modulation function as shown in Figure 1, electromyographic signal pickoff electrode 1 is close to human epidermal, is used for the introducing of human body electromyographic signal, by the electromyographic signal of electrode 1 introducing; Amplify through pre-amplification circuit 2, signal gets into next stage signal pre-processing circuit 3 then, carries out LPF, high-pass filtering and 50Hz notch by pre-process circuit 3 and handles; The signal of handling gets into from gain circuitry 4, accomplishes Gain Automatic adjusting, then; Signal is changed through A/D, gets into MSP430 microprocessor 6, after 6 integrated treatments of electromyographic signal microprocessor; Export corresponding signal, artificial hand controlled drive circuit 7 is realized speed regulation.

The pre-amplification circuit main amplifier is selected the AD620 instrumentation amplifier for use; From the amplifier of gain amplifying circuit 4, select the programmable amplifier PGA112 of Texas Instrument for use; Control system core---microprocessor is selected the MSP430F149 chip for use.

The proportionality velocity modulation method of this novel practical system: different according to the electromyographic signal intensity that collects; Pwm signal dutycycle to the artificial hand controlled drive circuit is regulated; And then change the ON time of drive circuit in unit period of doing evil through another person; Promptly change the drive circuit voltage effective value, finally realize doing evil through another person speed regulation.

Confirming of pwm signal dutycycle.The definite of pwm signal dutycycle realizes in two steps.The first step is the calculating of electromyographic signal intensity; Second step was according to the electromyographic signal intensity that calculates, and calculated the pwm signal dutycycle.

Electromyographic signal intensity is calculated.So-called electromyographic signal intensity is calculated the calculating that refers to the myoelectricity intensity that will be used for definite pwm signal dutycycle.To the calculating of electromyographic signal intensity, adopt the method for averaging.To the electromyographic signal that collects, be one group with 10 sampled points, divide into groups, with the meansigma methods of trying to achieve, replace the value of these ten sampled points, so, just accomplished finding the solution of electromyographic signal intensity.As use x _iThe first sampled point electromyographic signal intensity of representing i group sampled point,

I group sampled point myoelectricity intensity after expression is averaged.Concrete calculating is shown in formula (1):

${\stackrel{\‾}{x}}_i=\frac{1}{10}\underset{j=i}{\overset{i+9}{\mathrm{\Σ}}}{x}_j,(i=\mathrm{1,2,3,4}\·\·\·)---\left(1\right)$

To being positioned at last group sampled point of sampling queue afterbody, perhaps sampling number is discontented 10.Therefore, last group sampled point is not carried out mean value computation, directly use the average of its 10 sampled points of last group, replace last group electromyographic signal average.

Calculate the pwm signal dutycycle.If the corresponding pwm signal dutycycle of the maximum one group of sampled point of myoelectricity intensity is 1, then the calculating of the pwm signal dutycycle under other varying strength is shown in formula (2):

$\mathrm{\η}=\frac{{\stackrel{\‾}{x}}_i-{\stackrel{\‾}{x}}_0}{{\stackrel{\‾}{x}}_{\max }-{\stackrel{\‾}{x}}_0}\×100\%,(i=\mathrm{1,2,3,4}\·\·\·)---\left(2\right)$

η representes the dutycycle of pwm signal;

expression i group electromyographic signal average; One group of sampled point average that

electromyographic signal intensity is maximum, the generation threshold value of

expression electromyographic signal.

Claims (1)

1. the myoelectric prosthetic hand control method with real-time speed regulating function is characterized in that, specifically comprises the steps:

1) the electromyographic signal pickoff electrode is close to human epidermal, is used for the introducing of human body electromyographic signal;

2) electromyographic signal of being introduced by electrode is amplified through pre-amplification circuit, and signal gets into the next stage signal pre-processing circuit then; Carrying out LPF, high-pass filtering and 50Hz notch by pre-process circuit handles; The signal of handling gets into from gain circuitry, accomplishes Gain Automatic adjusting, then; Signal is changed through A/D, gets into the MSP430 microprocessor;

3) microprocessor carries out confirming of pwm signal dutycycle: the first step is to adopt the electromyographic signal intensity of averaging, and uses x _iThe first sampled point electromyographic signal intensity of representing i group sampled point,

I group sampled point myoelectricity intensity after expression is averaged, concrete computing formula: Last group sampled point to being positioned at the sampling queue afterbody does not carry out mean value computation, directly uses the average of its sampled point of last group, replaces last group electromyographic signal average; Second step was according to the electromyographic signal intensity that calculates, and calculated the pwm signal dutycycle, computing formula:

η representes the dutycycle of pwm signal,

Represent i group electromyographic signal average, One group of sampled point average that electromyographic signal intensity is maximum,

The generation threshold value of expression electromyographic signal;

4) back dutycycle pwm signal artificial hand controlled drive circuit is calculated in microprocessor output, realizes doing evil through another person speed regulation.

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