SU1067352A1 - Method and device for measuring object position - Google Patents

Abstract

1. A method of measuring the position of an object, which consists in obtaining an image of a diaphragm projected onto a photoconverter, spatially related to the position of an object, converting an image projected onto a photoconverter into a video signal, measuring the number of pulses with a frequency equal to or a multiple of the frequency of the video pulses. 2 fill the first time interval, the beginning of which coincides with the beginning of the formation of the video signal, characterized in that, in order to improve the measurement accuracy, a second time interval is formed, the duration of which is proportional to the width of the image of the diaphragm, and the beginning of the second time interval coincides with the end of the time interval, measure the number of pulses with a frequency equal to or a multiple of the frequency of video pulses that fill the second time interval, the frequency of the pulses that fill the first time interval, twice the frequency of the pulses filling the second time interval, and the width of the diaphragm image is not equal to the period of application of the photosensitive cells of the photovoltaic converter, the number of pulses filling the first time interval is summed up with the number of pulses filling the second time interval, and by the sum found, judging the position of the object.

Description

2. A device for measuring the position of an object containing an optically coupled light source, a diaphragm, an aperture imaging unit, a photodetector made on the basis of a charge-coupled device, a sampling unit, an input connected to the photodetector output, a control unit whose first output is connected with the control input of the photodetector, the counter and the recorder, the input of which is connected to the estimator, characterized in that, in order to improve the measurement accuracy, it is equipped with an amplitude discriminator whose input is connected to the output of the sampling unit, the frequency driver, whose input is connected to the second output of the control unit, the switching unit, the first and second information inputs of which are connected respectively to the output of the amplitude discriminator and the output of the frequency driver, the control input of the switching unit is connected to the third output of the control unit, and the output of the switching unit is connected to the counting input of the counter.

one

The invention relates to a measurement technique and can be used to measure linear and angular movements of various objects, for example, in autocollimation angle sensors.

There is a known method for measuring the position of an object, such as an image, in that a diaphragm image projected onto a phototransducer is obtained, spatially associated with. the position of the object, convert the image of the diaphragm projected onto the photoconverter into an electric signal.

The electrical signal is converted into a control signal, shifting the image of the diaphragm to a position in which the control signal is close to zero, and judging by the magnitude of the movement of the diaphragm images, it is judged polo. object.

A device is known for measuring the position of an object, comprising an optically coupled light source, a diaphragm, an aperture isofragment block, a photodetector, an information signal processing unit, the input of which is connected to a photoconductor.

The device also contains compensators associated with the outputs of the information signal processing unit, and the photodetector is made coordinate-sensitive.

The disadvantage of the method and device is low speed.

The closest technical solution to the invention is a method for measuring the position of an object, in that it obtains an image of a diaphragm projected onto a phototransducer spatially associated with the position of an object, transform an image projected onto a phototransducer into

video signal, measure the number of pulses with a frequency equal to or a multiple of the frequency of video pulses, filling the first time interval, the beginning of which coincides with the beginning of the formation of video signal 2.

The method is implemented by a device for measuring the position of an object containing an optically coupled light source, a diaphragm, a diaphragm imaging unit, a photodetector made on a charge-coupled device, a sampling unit, an input connected to the photodetector output, a control unit whose first output is connected with the control input of the photodetector, the counter and the recorder, the input of which is connected to the counter 2.

The method and device is characterized by insufficient measurement accuracy caused by the discreteness of the spatial arrangement of the photosensitive elements of the photodetector and the influence of the magnitude of the illumination in the image of the diaphragm.

The purpose of the invention is to improve the measurement accuracy.

This goal is achieved by the fact that, according to the method of measuring the position of an object, which consists in obtaining an image of a diaphragm projected onto a photovoltaic unit, spatially related to the position of an object, the number of pulses with a frequency equal to or a multiple of the frequency of a video equal to or a frequency of a video equal to or equal to or equal to filling the first time interval, the head of which coincides with the beginning of the formation of the video signal form the second time interval, the duration which is proportional to the width of the diaphragm image, with the beginning of the second time interval coinciding with the end of the first time interval, the number of pulses with a frequency equal to or a multiple of the frequency of video pulses filling the second time interval is measured, the frequency of the pulses filling the first time interval is twice the frequency pulses, filler the second time interval, and the width of the image of the diaphragm is not equal to the period of application of the photosensitive cells of the photoconverter, summarize the number and pulses, stuffing the first time interval with the number of pulse stuffing second time interval, and based on the detected amount of bud t object position. The goal is achieved by the fact that in a device for measuring the position of an object containing an optically coupled light source, an aperture imaging unit, a photodetector made on the basis of a device with a charge coupling, a sampling unit input connected to the output of the photodetector, the control unit, the first the output of which is connected to the control input of the photodetector, the counter and the recorder, the input of which is connected to the counter, is provided with an amplitude discriminator whose input is connected to the output of the sampling unit, frequency The input of which is connected to the second output of the control unit, the switching unit, the first and second information inputs of which are connected respectively to the amplitude discrimination discriminator output and the frequency driver output, the control input of the control unit, and the output of the switching unit are connected to the counter input of the counter . The drawing shows a functional diagram of a device implementing a method for measuring the position of an object. The device contains a source 1 of light, aperture 2, a diaphragm imaging unit 3 consisting of a beam-splitting element 4 of objective 5, a photodetector b made on the basis of a charge-coupled device, a control unit 7, a sampling unit 8, an amplitude discriminator consisting of peak detector 10, divider 11, comparator 12, switching unit 1 consisting of trigger 1 of element 15 AND, element 16 OR, counter 17, frequency driver 18, consisting of drivers 19, 20, element 21 OR, element 22 of delay the recorder 23. The device works as follows .. The light source 1 illuminates the aperture 2, the image of which, reflected from the object 24, is transferred by the aperture imaging unit 3 with the help of a beam-splitting element 4 and the lens 5 to the surface of the photodetector 6. diaphragm and 2 along the surface of the photodetector 6. The control unit 7 periodically interrogates the photodetector 6, at the output of which video pulses are formed, the envelope of which is proportional to the distribution of illumination in the image diaphragm 2. The signals taken from the photodetector .6, are input to the sampling unit 8, the guide carried synchronous sampled video pulses taken from the photodetector. The sampling rate is synchronized with the sampling frequency of the photodetector 6. The signals from the output of the sampling unit 8 are fed to the input of the peak detector 10 entering the amplitude discriminator 9. The peak detector 10 stores the maximum amplitude of the video pulses. The signal taken from the output of the peak detector 10 is divided by the divider 11 and fed to one of the inputs of the comparator 12, to another input of which a signal is output from the block 8 of the sample. When polling the photodetector 6 at the output of the comparator 12, a burst of pulses is formed when the signal taken from the output of sample block 8 is exceeded, which exceeds half the amplitude value of the video pulses. The comparing level can be controlled by the divider 11. At the beginning of the photodetector 6 polling cycle, the control unit 7 generates a reset signal, flip-flop trigger 14, entering the switching unit 13 in the unit state and resetting counter 17. After the reset pulse is generated, the control unit-7 generates polling pulses photodetector 6.,. I The control unit 7 generates pulses with a photo-receiver interrogation frequency, which arrive at the inputs of the formers 19, 20 of the frequency driver 18. The pulses from the outputs of the formers 19 and 20, formed on the leading and trailing edges, arrive at the inputs of the element 21 OR, from the output of which the delay element 22 arrives at the first input of the element 15 and. The frequency of the signals taken from the output of the delay element 22 is equal to the double sampling frequency of the photodetector 6. The delay element 22 serves to compensate for the time shifts in the nodes of the device.

At the second input element 15 And the resolving potential arrives from the trigger output 14,

The signals taken from the output of the element 15 AND / pass through the element 16 OR and are counted by the counter 17

When forming a signal at the output of the comparator 12, the trigger 14 is thrown and locks the element 15 I. The pulses from the output of the comparator 12 pass through the element 16 OR and are counted by the counter 17,

The result accumulated in counter 17 is recorded by the registrar 23,

Thus, in one polling cycle, in the counter 17 a result is accumulated equal to

N 2N1 + N2, where Nj-ij is the number of pulses,

accumulated, in the counter; 2N1 is the number of pulses corresponding to the unlighted part of the photodetector;

N2 is the number of pulses corresponding to the exposed part of the photodetector.

The result accumulated in the counter 17 corresponds with a certain scale factor to the position of the energy maximum illumination in the image of the diaphragm 2, whose position is related to the position of the object 24,

The use of the method and device (its implementation allows to determine the geometrical coordinate of the position of the Energy maximum of illumination in the image of the diaphragm T, e, the position of the object when the magnitude of the luminous flux is changed, with an error less than the error caused by the discontinuity of applying the photosensitive areas of the photoconverter.

Claims (2)

1. The method of measuring the position of an object, which consists in obtaining a diaphragm projected onto a photoconverter, spatially related to the position of the object, converting an image projected on a photoconverter into a video signal, measuring the number of pulses with a frequency equal to or a multiple of the frequency of the video pulses filling the first time interval, the beginning of which coincides with the beginning of the formation of the video signal, characterized in that, in order to improve the measurement accuracy, form a second time inter al, the duration of which is proportional to the width of the aperture image, and the beginning of the second time interval coincides with the end of the first time interval, measure the number of pulses with a frequency equal to or a multiple of the frequency of video pulses filling the second time interval, the frequency of pulses filling the first time interval, twice the high frequencies of the pulses filling the second time interval, and the width of the image of the diaphragm is not equal to the period of application of the photosensitive cells of the photoconverter, summarize the number of pulses filling the first time interval, with the number of pulses filling the second time interval, and the position of the object is judged by the sum found. SU. ,,, 1067352 2. A device for measuring the position of an object, containing optically coupled light source, aperture, an aperture imaging unit, a photodetector based on a charge-coupled device, a sampling unit connected to the output of the photodetector, a control unit, the first output of which is connected to a control input a photodetector, a counter and a recorder, the input of which is connected to a meter, characterized in that, in order to increase the accuracy of the measurement, it is equipped with an amplitude discriminator, the input of which is connected to the output of the sampling unit, by a frequency driver, the input of which is connected to the second output of the control unit, a switching unit, the first and second information inputs of which are connected respectively to the output of the amplitude discriminator and the output of the frequency driver>, the control input of the switching unit is connected to the third output of the control unit, and the output of the switching unit is connected to the counter input of the counter.