CN102853862A - Error detection method during debugging of space encoder - Google Patents

Abstract

The invention discloses an error detection method during debugging of a space encoder and relates to an encoder error detection technology. The problems that introduced errors are inaccurate and operation processes are complex in the encoder debugging process of manual operation and detection are solved. The method comprises that photoelectric conversion and amplitude adjustment of photoelectric encoder signals can be achieved, photoelectric encoder signals are subjected to differential amplification through an amplifier and two channels of signals are output to an analog to digital (A/D) converter; two channels of signals which are subjected to the differential amplification are converted by the A/D converter and are sent to a single chip microcomputer, and the single chip microcomputer transmits collected signals to a personal computer (PC) through a universal serial bus (USB) port; software programs on the PC are used for conducting discrete Fourier transform for received signals based on non-uniform sampled signals; waveform parameters of the photoelectric encoder signals are obtained; and the detection of introduced errors during debugging of the space encoder is achieved. By the aid of the method, the accuracy of the space encoder is improved, and the effect of introduced errors on encoder accuracy is small during debugging.

Description

Space flight encoder debugging process error detection method

Technical field

The present invention relates to a kind of encoder errors detection technique, be specifically related to the method for a kind of space flight encoder debugging Process Precision analysis and error-detecting.

Background technology

In the design of camera space, the focusing system part that is absolutely necessary, its precision directly affects image planes control accuracy and the image quality of camera, and photoelectric encoder important detecting element wherein especially.Therefore, tackle it and strictly accurately debug, to realize accurately location and measurement, guarantee the precision of focusing control system.

At present, in space flight encoder debugging process, Circuits System on the impact of scrambler precision mainly from smart decoding circuit.The error that the essence decoding circuit is introduced mainly contains: signal amplitude does not wait, remains DC level, AD conversion etc.

Use adjustable potentiometer to realize opto-electronic conversion and the range-adjusting of signal in the encoder debugging circuit, and space product does not allow to use potentiometer, at the resistance of two standard fixed resistance value of this apolegamy, adopts parallel form to connect and substitutes potentiometer.Because the resistance of measuring resistance is discontinuous, therefore the resistance of apolegamy can not be fully and potentiometer resistance mate.Remain DC level thereby cause signal amplitude not wait and produce, code device signal has been introduced error.Whether the detection hardware circuit was by manually-operated to the method that code device signal is introduced error in the past, selected regulating rod slowly to regulate the scrambler rotating shaft, measured on four direction the monocycle essence with multimeter simultaneously and piled up the maximal value V of large-signal _MaxWith minimum value V _MinThereby, calculate the residue DC level of variation and the generation of signal amplitude.Existing method can only use manually-operated to process, and complicated operation detects out of true, and the error of can't accurate analysis introducing is on the impact of scrambler precision.

Summary of the invention

The present invention is existing by introducing the inaccuracy of error and the complicacy of operating process in the manually-operated detection encoder debugging process for solving, and a kind of space flight encoder debugging process error detection method is provided.

Space flight encoder debugging process error detection method, the method is:

Step 1, photoelectric encoder signal are realized opto-electronic conversion and range-adjusting by apolegamy resistance, export two paths of signals to A/D converter through the amplifier differential amplification again;

A/D converter described in step 2, the step 1 is sent into single-chip microcomputer after with the conversion of the two paths of signals of differential amplification, single-chip microcomputer with the signal that collects through the USB port transmission to PC;

Step 3, adopt the software program on the PC that the signal that receives is carried out discrete Fourier transformation based on non-uniformly sampled signals; Obtain the waveform parameter of photoelectric encoder signal; The final realization introducing the detection of error in the space flight encoder debugging process.

Beneficial effect of the present invention: one, of the present invention being applicable to debugged and accuracy detection and analysis multiple space flight scrambler, and simple to operate, real-time is good, is easy to carry about with one; Two, the present invention finishes detection and the analysis of code device signal by the software program on the application PC, has substituted manually-operated, and convenient and swift, accuracy is high; Three, method of the present invention is that signal resistance is chosen in the formal PCB welding of scrambler in the camera space, assessed simultaneously the error of introducing when the resistance of potentiometer and rear distribution is exchanged, finish the scrambler accuracy detection, and can more early find the problem that code device signal exists, in time deal with; Four, in the method for the present invention single-chip microcomputer and PC are combined, the chip major part in the debug system hardware circuit is the employed chip of on-board equipment, and the experience of Heaven flight was arranged, and satisfies the requirement of space product high reliability and stability.

Description of drawings

Fig. 1 is the structured flowchart of space flight encoder debugging process error detection method of the present invention.

Embodiment

Embodiment one, in conjunction with Fig. 1 present embodiment is described, space flight encoder debugging process error detection method, the method is mainly for the error-detecting of the smart coded signal of photoelectric encoder, described photoelectric encoder essence coded signal is realized opto-electronic conversion and range-adjusting by adjustable potentiometer, and the resistance with the standard fixed resistance value of matching substitutes adjustable potentiometer again.The smart coded signal that four tunnel phase place mutual deviations are 90 ° is through amplifier differential amplification output Asin θ and Acos θ two paths of signals, again by sending into single-chip microcomputer after the A/D converter conversion.Observe two paths of signals with oscillograph simultaneously.The thick coded signal data of essence that single-chip microcomputer will collect by the USB port transmission to PC.On PC, the program of using among the MATLAB is carried out discrete Fourier transformation based on non-uniformly sampled signals to the Asin θ of essence code and Acos θ two paths of signals, thereby obtains the waveform parameter of code device signal and according to signal quality the impact of subdivision error is calculated the scrambler subdivision error.The discrete Fourier series transfer pair that is defined as follows:

$X_{\mathrm{NU}}\left(k\right)=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}x\left(t_n\right)e^{-j\left(\frac{2\mathrm{\π}}{N}\right)\mathrm{nk}},k=\mathrm{0,1,2},...,N-1---\left(1\right)$

$x\left(t_n\right)=\frac{1}{N}\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{X}_{\mathrm{NU}}\left(k\right)e^{-j\left(\frac{2\mathrm{\π}}{N}\right)\mathrm{nk}},---\left(2\right)$

In the formula Periodic sequence x (t _n) fundamental component,

Be the k order harmonic components, j is empty unit, and the coefficient of each harmonic is X _NU(k), N is x (t _n) finite length.

Nonuniform sampling is defined as constantly:

t _n=nT+τ，n=0，1，…，N-1

T is the time interval of uniform sampling in the formula, and τ is that average is 0, obeys the random quantity of same probability distribution.The amplitude computing formula of deriving signal according to discrete Fourier transformation is:

$A=\frac{2}{N}\left|X_{\mathrm{NU}}\left(m\right)\right|---\left(3\right)$

X in the formula _NU(m) be m subharmonic coefficient, occur the maximum value of discrete Fourier transformation frequency spectrum at m root spectral line place.

Obtain the change of DC level by the amplitude that calculates, thereby the error according to formula (4) during to encoder debugging detects analysis.

The error that residue DC level component is introduced scrambler is:

$\mathrm{\Δ\ψ}\≈\frac{P}{2\mathrm{\π}}\left|\frac{\mathrm{\ΔUo}}{U}\right|---\left(4\right)$

P is the pitch of segmentation code channel, P=360 ^o/ 256=5062.5 ", Δ Uo is the residue DC level, and U is operating voltage.

The described photoelectric encoder of present embodiment is selected camera space focusing system intermediate-resolution be 80 14 absolute photoelectric shaft encoders of ", precision＜± 100 "; The resistance of described standard fixed resistance value is the Chip-R of precision 1%, and adjustable potentiometer is BOUNS 3296; The amplifier model is LM124; A/D converter is 12, multi-channel high-speed CMOS serial a/d conversion chip, and model is TLV2548; Described single-chip microcomputer is 80C32E; Use the detection that MATLAB software is realized signal amplitude, phase place, frequency on the PC.

Adopt in the present embodiment chip microcontroller code device signal data by hardware circuit amplification, comparison, shaping, conversion afterwards to the transmission of PC.Application program on the employing PC is to carrying out the detection of frequency, amplitude, phase place based on the signal of nonuniform sampling, computational analysis goes out the error that hardware circuit is introduced, and real-time display error analysis result.In space flight encoder debugging process, the method is that signal resistance is chosen in the formal PCB welding of scrambler in the camera space, has assessed simultaneously the error of introducing when the resistance of potentiometer and rear distribution is exchanged, and finishes the scrambler accuracy detection.

Embodiment two,

Present embodiment is the embodiment of embodiment one described space flight encoder debugging process error detection method:

Take a certain model high-resolution camera as example, introduce camera focusing encoder debugging process.System selects the potentiometer group to adjust the output signal amplitude, measures the resistance of potentiometer with multimeter, calculates and match again the resistance of fixed resistance value according to potentiometer resistance.Table 1 is the resistance table of comparisons.

The table 1 resistance table of comparisons (Ω)

At first select potentiometer to adjust the output signal amplitude in the present embodiment, single-chip microcomputer with the encoder data communication to PC, recording signal maximum at PC by MATLAB is 5.01V, minimum value is 0.01V, when the encoderless input signal, recording the residue DC level is 0.01V, obtains the error △ Ψ that circuit is introduced according to formula (4) ₁≈ ± 3.22 ".Then select rear distribution resistance to replace potentiometer, recording signal maximum is 4.97V, and minimum is 0.03V, and the residue DC level during the encoderless input signal is 0.03V, introduces error △ Ψ ₂" in addition, when changing essence code amplifier, the discreteness that different amplifier output DCs are flat produces the residue DC level and is about ± 0.01V, introduces error △ Ψ in ≈ ± 9.45 ₃≈ ± 3.22 ".Can find out because the resistance of apolegamy can not be fully mated with potentiometer resistance, remain DC level thereby cause signal amplitude not wait and produce, code device signal has been introduced larger error.

The precision of the described institute of present embodiment debugging scrambler＜± 100 ", 1/10th of the not enough precision of the error that Circuits System is introduced is to scrambler Accuracy less.Therefore the photoelectric encoder of using method debugging of the present invention can work in the camera space focusing system.

Claims (3)

1. space flight encoder debugging process error detection method is characterized in that, the method is realized by following steps:

Step 1, photoelectric encoder signal are realized opto-electronic conversion and range-adjusting by apolegamy resistance, export two paths of signals to A/D converter through the amplifier differential amplification again;

A/D converter described in step 2, the step 1 is sent into single-chip microcomputer after with the conversion of the two paths of signals of differential amplification, single-chip microcomputer with the signal that collects through the USB port transmission to PC;

Step 3, adopt the software program on the PC that the signal that receives is carried out discrete Fourier transformation based on non-uniformly sampled signals; Obtain the waveform parameter of photoelectric encoder signal; The final realization introducing the detection of error in the space flight encoder debugging process.

2. space flight encoder debugging process error detection method according to claim 1, it is characterized in that, before step 1, also comprise the signal of photoelectric encoder output is realized opto-electronic conversion and range-adjusting by adjustable potentiometer, then adopt the resistance of standard fixed resistance value after parallel connection, to replace the step of adjustable potentiometer.

3. space flight encoder debugging process error detection method according to claim 1, it is characterized in that, step 1 is described when the amplifier differential amplification is exported two paths of signals to A/D converter, adopts the oscillograph observation through the two paths of signals of amplifier differential amplification.

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