CN106405139A - Rotary table angular rate detecting apparatus and method - Google Patents

Abstract

The invention belongs to the technical field of inertial device testing, and in particular relates to a detection device and method for an angular rate of a turntable. The device of the present invention includes a photoelectric encoder, a standard pulse processing circuit and a portable tester: the photoelectric encoder generates a 1Vpp differential signal when the measured axis of the turntable rotates, and the standard pulse signal processing circuit converts the 1Vpp differential signal into a standard single-ended TTL level signal, the portable tester counts standard single-ended TTL level signals. The method of the invention comprises the following steps: calculating the average time and angular rate; calculating the absolute error of the angular rate and the absolute error of the stability of the angular rate; calculating the relative error of the angular rate and the relative error of the stability of the angular rate. The invention realizes angular rate detection applicable to different types of turntables through traceable counting equipment, high-reliability encoders and processing circuits, can obtain processing results in real time, and has the characteristics of strong applicability and high timing accuracy.

Description

Device and method for detecting angular velocity of a turntable

technical field

The invention belongs to the technical field of inertial device testing, and in particular relates to a detection device and method for an angular rate of a turntable.

Background technique

The turntable is used as an inertial device testing equipment, and the accuracy and stability of its angular rate play a decisive role in the performance of the inertial device. With the continuous improvement of the angular rate index of inertial devices, the requirements for the accuracy index of the angular rate of the turntable system are also increasing.

At present, the detection of the angular rate is carried out from three intervals of 360° average, 10° average and 1° average according to the magnitude of the angular rate. When the angular rate command is greater than 360°, use the positional movement between the magnetic steel pasted on the turntable frame and the fixed Hall device to generate a Hall signal, and output it as a reference pulse signal to the test system to calculate the pulse interval time to perform Angular rate calculation; when the angular rate command is less than 10°, or even less than 1°, the 1ms interrupt inside the turntable control system is used to collect the angular position of the turntable to calculate the accuracy and stability of the angular rate.

Although the above method can complete the angular rate detection of the general turntable, it is only used in the state where the control data of the turntable can be opened to the angular rate detection state, and it is not suitable for the angular rate test of the turntable with the exclusive control system. There is mutual interference between the detection device and the control system, and the detection results Issues associated with the data acquisition of the control system.

Contents of the invention

The technical problem to be solved in the present invention is to provide a detection device and method for the angular rate of the turntable, which is separated from the angular rate detection device of the control system of the turntable itself, and has high test accuracy and strong applicability.

Technical scheme of the present invention is as follows:

A turntable angular rate detection device, including a photoelectric encoder, a standard pulse processing circuit and a portable calibration instrument: the photoelectric encoder generates a 1Vpp differential signal when the measured axis of the turntable rotates, and the standard pulse signal processing circuit converts the 1Vpp differential signal into a standard single The portable tester counts the standard single-ended TTL level signal.

As a preferred solution: the photoelectric encoder adopts a circular grating type photoelectric encoder. The circular grating photoelectric encoder includes a circular grating and a reading head: the circular grating is installed on the measured axis of the turntable, and the radial rotation error is less than or equal to 5 μm; the distance between the reading head and the outer edge of the circular grating is 2mm.

As a preferred solution: the standard pulse signal processing circuit includes a filter circuit and a high-speed conversion chip: the filter circuit performs filtering processing on the 1Vpp differential signal, and the high-speed conversion chip converts the 1Vpp differential signal into a TTL differential level under the premise of ensuring signal bandwidth, Then convert it into a single-ended signal to obtain a standard single-ended TTL level signal. The high-speed conversion chip can be a 74LS123 chip.

As a preferred solution: the portable tester includes a highly stable clock source and a signal acquisition and processing circuit, counts the falling edges of the standard single-ended TTL level signal, calculates the interval time of the standard single-ended TTL level signal, and calculates the turntable The time to turn through a fixed angle gives angular rate accuracy and stability. The high-stable clock source can use NI standard boards.

A method for detecting the angular rate of a turntable, comprising the following steps:

Step 1 Calculate the average time and angular rate

The turntable works in the speed state, so that it runs stably at a given speed, and starts to measure after the turntable runs stably; the portable calibration instrument samples n data in total; calculate the average time according to formula (1), and calculate the angular rate according to formula (2):

ω＝Δθ/T (2)

In the formula,

It is the average value of the time taken for the measured axis of the turntable to rotate through the fixed angle interval at a given speed;

n is the number of continuous measurements at a given rate point;

T _i is the time taken for the measured shaft of the turntable to turn through the fixed angle interval for the i time at a given speed, i=1, 2, ..., n;

ω is the theoretical value of the angular rate;

△θ is the fixed angle interval;

T is the time taken for the turntable to rotate through the fixed angle interval;

Step 2 Calculate the absolute error of the angular rate and the absolute error of the stationarity of the angular rate

When the turntable speed is less than 0.1°/s, calculate the absolute error of angular rate according to formula (3), and calculate the absolute error of angular rate stationarity according to formula (4)

in,

In the formula:

E _ω is the absolute error of the angular rate;

is the average angular rate;

is the absolute error of angular rate stationarity;

is the maximum positive deviation value of the measured value of each rate point relative to the average rate;

is the measured value of the rate point with the largest positive deviation from the rate mean;

is the maximum negative deviation value of the measured value of each rate point relative to the average rate;

is the measured value of the rate point with the largest negative deviation from the rate average;

Step 3 Calculate the relative error of the angular rate and the relative error of the stationarity of the angular rate

When the turntable speed is greater than or equal to 0.1°/s, the relative error of the angular rate is calculated according to formula (5), and the relative error of angular rate stability is calculated according to formula (6):

In the formula:

V _ω is the relative error of the angular rate;

T _g is the theoretical value of the time taken for the measured axis of the turntable to rotate through a fixed angle interval at a given rate;

σ _ω is the relative error of angular rate stationarity;

N is the number of measurements selected at a given rate.

As a preferred solution: in step 1, the value of Δθ is 360°, or 10° or 1°.

As a preferred solution: in step 3, in the 360° average section, N=10; in the 10° average section, N=10; in the 1° average section, when the theoretical value of the angular rate ω≥0.005°/s, N=10, when the theoretical value of angular rate ω<0.005°/s, N=3.

The beneficial effects of the present invention are:

(1) A turntable angular rate detection device and method of the present invention has a clear design principle and a clear actuator, and realizes angular rates applicable to different types of turntables through traceable counting equipment, high-reliability encoders and processing circuits detection;

(2) The device and method for detecting the angular rate of a turntable of the present invention can be installed and used immediately, and can obtain processing results in real time, and has the characteristics of strong applicability and high timing accuracy.

Description of drawings

Fig. 1 is a schematic composition diagram of the turntable angular rate detection device of the present invention;

Fig. 2 is a schematic diagram of the installation of the external circular grating photoelectric encoder of the present invention.

In the figure, 1-the measured axis of the turntable, 2-circular grating, 3-reading head clamp rod, 4-reading head, 5-photoelectric encoder mounting plate.

detailed description

A device and method for detecting the angular velocity of a turntable according to the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, a turntable angular rate detection device of the present invention includes a photoelectric encoder, a standard pulse processing circuit and a portable verification instrument: the photoelectric encoder generates a 1Vpp differential signal when the turntable measured axis 1 rotates, and the standard pulse signal The processing circuit converts the 1Vpp differential signal into a standard single-ended TTL level signal, and the portable tester counts the standard single-ended TTL level signal.

The photoelectric encoder adopts a circular grating photoelectric encoder. When the turntable moves at a certain speed at a constant speed, the circular grating photoelectric encoder generates a 1Vpp differential signal corresponding to its line number. As shown in Figure 2, the circular grating photoelectric encoder in this embodiment includes a circular grating 2 and a reading head 4: the circular grating 2 is installed on the measured axis 1 of the turntable, and the radial rotation error is not greater than 5 μm; the reading head 4 and The outer edge distance of the circular grating 2 is 2mm, which is used to generate a 1Vpp differential signal when the measured axis 1 of the turntable rotates. When the number of lines is 18000, and the rotation speed of the turntable is 360°/s, the circular grating photoelectric encoder can output 18000 cycle signals per turn of the turntable.

The standard pulse signal processing circuit includes a filter circuit and a high-speed conversion chip: the filter circuit filters the 1Vpp differential signal, and the high-speed conversion chip converts the 1Vpp differential signal into a TTL differential level on the premise of ensuring the signal bandwidth, and then converts it to For a single-ended signal, a standard single-ended TTL level signal is obtained. In this embodiment, the filter circuit is realized by using high-reliability resistors and capacitors; the high-speed conversion chip uses a 74LS123 chip.

The portable calibration instrument includes a highly stable clock source and a signal acquisition and processing circuit, which can count the falling edges of the standard single-ended TTL level signal and calculate the interval time of the standard single-ended TTL level signal. Time to obtain angular rate accuracy and stability. In this embodiment, the high stability clock source adopts NI standard board; the signal acquisition and processing circuit adopts the signal acquisition circuit in the prior art, which is common knowledge of those skilled in the art.

A method for detecting the angular velocity of a turntable of the present invention is realized by using a fixed angle timing method, and it specifically includes the following steps:

Step 1 Calculate the average time and angular rate

The turntable works in the speed state, so that it runs stably at a given speed, and the measurement starts after the turntable runs stably. The portable calibration instrument samples n data in total. The average time is calculated according to formula (1), and the angular rate is calculated according to formula (2):

ω＝△θ/T (2)

In the formula,

It is the average value of the time taken for the measured axis of the turntable to rotate through the fixed angle interval at a given speed;

n is the number of continuous measurements at a given rate point, in this embodiment, n=10;

T _i is the time taken for the measured shaft of the turntable to turn through the fixed angle interval for the i time at a given speed, i=1, 2, ..., n;

ω is the theoretical value of the angular rate;

Δθ is a fixed angle interval. In this embodiment, Δθ can take a value of 360°, 10° or 1°;

T is the time taken for the turntable to rotate through the fixed angle interval.

Step 2 Calculate the absolute error of the angular rate and the absolute error of the stationarity of the angular rate

When the turntable speed is less than 0.1°/s, calculate the absolute error of angular rate according to formula (3), and calculate the absolute error of angular rate stationarity according to formula (4)

in,

In the formula:

E _ω is the absolute error of the angular rate;

is the average angular rate;

is the absolute error of angular rate stationarity;

is the maximum positive deviation value of the measured value of each rate point relative to the average rate;

is the measured value of the rate point with the largest positive deviation from the rate mean;

is the maximum negative deviation value of the measured value of each rate point relative to the average rate;

is the rate point measurement with the largest negative deviation from the rate mean.

Step 3 Calculate the relative error of the angular rate and the relative error of the stationarity of the angular rate

When the turntable speed is greater than or equal to 0.1°/s, the relative error of the angular rate is calculated according to formula (5), and the relative error of angular rate stability is calculated according to formula (6):

In the formula:

V _ω is the relative error of the angular rate;

T _g is the theoretical value of the time taken for the measured axis of the turntable to rotate through a fixed angle interval at a given rate;

σ _ω is the relative error of angular rate stationarity;

N is the number of measurements selected at a given rate.

In this embodiment, in the 360° average section, N=10; in the 10° average section, N=10; in the 1° average section, when the theoretical value of the angular rate ω≥0.005°/s, N=10 , when the theoretical value of angular rate ω<0.005°/s, N=3.

Claims (10)

1. A turntable angular rate detection device, comprising a photoelectric encoder, a standard pulse processing circuit and a portable calibration instrument, is characterized in that: the photoelectric encoder produces a 1Vpp differential signal when the turntable measured axis (1) rotates, and the standard pulse signal processing The circuit converts the 1Vpp differential signal into a standard single-ended TTL level signal, and the portable tester counts the standard single-ended TTL level signal. 2. The angular velocity detection device of the turntable according to claim 1, wherein the photoelectric encoder is a circular grating photoelectric encoder. 3. The rotary table angular rate detection device according to claim 2, characterized in that: the circular grating photoelectric encoder comprises a circular grating (2) and a reading head (4): the circular grating (2) is installed on the rotary table to be measured On the axis (1), the radial rotation error is less than or equal to 5 μm; the distance between the reading head (4) and the outer edge of the circular grating (2) is 2 mm. 4. The turntable angular velocity detection device according to claim 1, characterized in that: said standard pulse signal processing circuit comprises a filter circuit and a high-speed conversion chip: the filter circuit carries out filter processing to the 1Vpp differential signal, and the high-speed conversion chip ensures that the signal Under the premise of bandwidth, the 1Vpp differential signal is converted into a TTL differential level, and then converted into a single-ended signal to obtain a standard single-ended TTL level signal. 5. The turntable angular velocity detection device according to claim 4, characterized in that: the high-speed conversion chip is a 74LS123 chip. 6. turntable angular rate detection device according to claim 1, is characterized in that: described portable calibration instrument comprises highly stable clock source and signal acquisition and processing circuit, counts the falling edge of standard single-ended TTL level signal, counts The standard single-ended TTL level signal interval time is calculated, and the angular rate accuracy and stability are obtained by calculating the time for the turntable to rotate through a fixed angle. 7. The angular rate detection device of the turntable according to claim 6, characterized in that: the high stability clock source adopts NI standard board. 8. A method for detecting the angular rate of a turntable, characterized in that: comprising the following steps: Step 1 Calculate the average time and angular rate The turntable works in the speed state, so that it runs stably at a given speed, and starts to measure after the turntable runs stably; the portable calibration instrument samples n data in total; calculate the average time according to formula (1), and calculate the angular rate according to formula (2): $\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$ ω＝△θ/T (2) In the formula, It is the average value of the time taken for the measured axis of the turntable to rotate through the fixed angle interval at a given speed; n is the number of continuous measurements at a given rate point; T _i is the time taken for the measured shaft of the turntable to turn through the fixed angle interval for the i time at a given speed, i=1, 2, ..., n; ω is the theoretical value of the angular rate; △θ is the fixed angle interval; T is the time taken for the turntable to rotate through the fixed angle interval; Step 2 Calculate the absolute error of the angular rate and the absolute error of the stationarity of the angular rate When the turntable speed is less than 0.1°/s, calculate the absolute error of angular rate according to formula (3), and calculate the absolute error of angular rate stationarity according to formula (4) ${\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&omega;</span>}<span\; class="notranslate">\; -</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}\mathrm{<span\; class="notranslate">\; ...</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$ ${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; \{</span><span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; x</span>}}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; x</span>}}^{<span\; class="notranslate">\; -</span>}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; \}</span>\mathrm{<span\; class="notranslate">\; ...</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$ in, $\left\{\begin{array}{c}\stackrel{\&OverBar;}{\mathrm{\&omega;}}=\frac{\mathrm{\&Delta;}\mathrm{\&theta;}}{\stackrel{\&OverBar;}{T}}\\ {\mathrm{\&Delta;\&omega;}}_{\max }^{+}={\mathrm{\&omega;}}_{\max }^{+}-\stackrel{\&OverBar;}{\mathrm{\&omega;}}\\ {\mathrm{\&Delta;\&omega;}}_{\max }^{-}={\mathrm{\&omega;}}_{\max }^{-}-\stackrel{\&OverBar;}{\mathrm{\&omega;}}\end{array}\right.$ In the formula: E _ω is the absolute error of the angular rate; is the average angular rate; σ′ _ω is the absolute error of angular rate stationarity; is the maximum positive deviation value of the measured value of each rate point relative to the average rate; is the measured value of the rate point with the largest positive deviation from the rate mean; is the maximum negative deviation value of the measured value of each rate point relative to the average rate; is the measured value of the rate point with the largest negative deviation from the rate average; Step 3 Calculate the relative error of the angular rate and the relative error of the stationarity of the angular rate When the turntable speed is greater than or equal to 0.1°/s, the relative error of the angular rate is calculated according to formula (5), and the relative error of angular rate stability is calculated according to formula (6): ${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; |</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}}\mathrm{<span\; class="notranslate">\; ...</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$ ${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; ...</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$ In the formula: V _ω is the relative error of the angular rate; T _g is the theoretical value of the time taken for the measured axis of the turntable to rotate through a fixed angle interval at a given rate; σ _ω is the relative error of angular rate stationarity; N is the number of measurements selected at a given rate. 9. A method for detecting the angular velocity of a turntable according to claim 8, characterized in that: in step 1, the value of Δθ is 360°, or 10° or 1°. 10. A method for detecting the angular velocity of a turntable according to claim 8, characterized in that: in step 3, in the 360° average section, N=10; in the 10° average section, N=10; 1° average In the section, when the theoretical value of the angular rate ω≥0.005°/s, N=10, and when the theoretical value of the angular rate ω<0.005°/s, N=3.