SU1714349A1

SU1714349A1 - Photoelectric sensor

Info

Publication number: SU1714349A1
Application number: SU894680571A
Authority: SU
Inventors: Григорий Яковлевич Кивензор; Соломон Матусович Креймерман; Александр Михайлович Фишман; Александр Иосифович Ярмолинский
Original assignee: Одесское специальное конструкторское бюро полиграфического машиностроения
Priority date: 1989-04-18
Filing date: 1989-04-18
Publication date: 1992-02-23

Abstract

Изобретение относитс к измерительной технике и может быть применено дл контрол взаимного положени деталей иузлов машин . Цель изобретени ~ повышение точности. При перемещении контролируемого объекта вдоль линии, перпендикул рной ребру контрольного элемента, укрепленного неподвижно, фотоприемники не освещены до тех пор^ пока элемент не входит в зону, близкую к оси пирамидального корпуса. При этом свет излучателей 3 отражаетс гран ми сигнального (контрольного) элемента в плоскости падени , параллельной его ребру. В зависимости от рассто ни между оптическими ос ми пары излучатель - фотоприемник в плоскости нижней грани пирамиды производитс выбор высоты корпуса. 2 ил.The invention relates to a measurement technique and can be applied to control the relative position of parts and components of machines. The purpose of the invention ~ improving accuracy. When the controlled object is moving along a line perpendicular to the edge of the control element, fixed forwards, the photodetectors are not illuminated until the element enters the zone close to the axis of the pyramidal body. In this case, the light of the emitters 3 is reflected by the edges of the signal (control) element in the plane of incidence parallel to its edge. Depending on the distance between the optical axes of the emitter-photodetector pair in the plane of the pyramid's lower face, the height of the housing is selected. 2 Il.

Description

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Изобретение относитс к измерительной технике и может быть применено дл контрол взаимного положени деталей и узлов машин в различных отрасл х машиностроени .The invention relates to a measurement technique and can be applied to control the relative position of machine parts and assemblies in various fields of engineering.

Известны фотозлектрические датчики контрол положени , содержащее излучатель , сдвоенный фотоприемних и сигнальный злемент, выполненный в виде щелевой диафрагмы или флажка и жестко св занный с контролируемым объектом,Photoelectric position control sensors are known, comprising a radiator, a dual photodetector, and a signal element, made in the form of a slit diaphragm or flag, and rigidly associated with the object being monitored,

Фотоприемники расположены р дом, а между ними и излучателем проходит сигнальный злемент. При определенном пространственном положении объекта сигнальный злемент обеспечивает динамическое уравнивание сигналов фотоприемников и выработку выходного дифференциального сигнала, фpoнt которого фиксирует информацию о положении объекта.Photodetectors are located near, and between them and the emitter passes the signal element. At a certain spatial position of the object, the signal element provides a dynamic equalization of the signals of the photodetectors and the generation of an output differential signal, the frst of which records information about the position of the object.

Известные датчики характеризуютс ограниченной точностью и помехоустойчивостью , так как при смещении сигнального элемента из произвольного положени в заданное , вначале один из фотоприемников полностью освещаетс , второй полностью затемн етс , а затем происходит уравнивание фотозлектрических сигналов при промежуточных уровн х освещенности. Таким образом, флажок, прикрепленный к контролируемому объекту, перераспредел ет освещенность фотоприемников с малой крутизной,что ограничивает точность определени положени . Применение линзовых систем дл увеличени сигнала усложн ет конструкцию и делает ее нетехналогичной. Невысока также помехоустойчивость известного датчика, так как вследствие различий в чувствительности фотоприемников фотозлектрические сигналъ уравниваютс не только в заданной зоне, но и при слабом затемнении флажком более чувствительного фотоприемника.The known sensors are characterized by limited accuracy and noise immunity, since when the signal element is shifted from an arbitrary position to a predetermined, first one of the photoreceivers is fully illuminated, the second is completely darkened, and then the photoelectric signals are equalized at intermediate light levels. Thus, the flag attached to the monitored object redistributes the illumination of photodetectors with a small steepness, which limits the accuracy of the position determination. The use of lens systems to increase the signal complicates the design and makes it non-similar. The noise immunity of a known sensor is also low, since, due to differences in the sensitivity of photodetectors, photoelectric signals are equalized not only in a given zone, but also when the more sensitive photodetector is slightly dimmed by the flag.

Наиболее близким к предлагаемому вл етс фотозлектрический датчик контрол положени , содержащий установленные в корпусе излучатель и два фотоприемника, расположенные под углом друг к другу, и сигнальный злемент, жестко св занный с контролируемым объектом. Корпус выполнен в виде щели, в которую вводитс сигнальный злемент в виде флажка. Оптические оси фотоприемников пересекаютс в центре излучател .Closest to the present invention is a photoelectric position control sensor comprising an emitter installed in the housing and two photodetectors at an angle to each other, and a signal element rigidly connected to the object being monitored. The housing is made in the form of a slit into which a signal element is inserted in the form of a flag. The optical axes of the photodetectors intersect at the center of the emitter.

Известное выполнение оптической схемы и сигнального злемента ограничивают точность измерени , определ емую малой крутизной изменени выходных сигналов в заданном положении контролируемого объекта . Помехоустойчивость известного датчика также невысока вследствие уравнивани сигналов при периферийном затемнении флажком более чувствительного из двух фотоприемникрв. Дл повышени помехоустойчивости необходимо специальное выполнение логической злектронной схемы, обрабатывающей сигналы датчика. Конструкци корпуса со щелью, с одной стороны которой установлен излучатель, а с другой 0 фотоприемники, усложнена и требует дополнительной регулировки положени фотоприемникрв .The known implementation of the optical circuit and the signal element limit the measurement accuracy determined by the small steepness of the change in the output signals in a predetermined position of the object being monitored. The noise immunity of the known sensor is also low due to the equalization of signals during peripheral dimming by the flags of the more sensitive of the two photodetectors. To improve noise immunity, special electronic logic circuit processing of the sensor signals is necessary. The housing design with a slit, on one side of which the emitter is installed, and on the other 0 photodetectors, is complicated and requires additional adjustment of the position of the photodetectors.

Цель изобретени - повышение точности и помехоустойчивости датчика и упро5 щение его конструкции.The purpose of the invention is to improve the accuracy and noise immunity of the sensor and simplify its design.

Поставленна целъ достигаетс тем, что фотозлектрический датчик, содержащий корпус, установленные в нем осветитель, фотоприемники, сигнальный злемент. предназначенный дл скреплени с объектом, и ре гистрирующий блок, снабжен вторым осветителем , корпус выполнен в виде равнобедренной четырехгранной пирамиды с отверсти ми дл размещени осветителей иThe goal is achieved by the fact that a photoelectric sensor, comprising a housing, an illuminator, photodetectors, and a signal element installed in it. intended for bonding with the object, and the registering unit is equipped with a second illuminator, the body is made in the form of an isosceles tetrahedral pyramid with openings for accommodating illuminators and

5 фотоприемников и ориентирован основанием к сигнальному злементу, который выполнен крышеобразным и с отражающим покрытием со стороны основани корпуса. а фотоприемники и осветители установлены5 photodetectors and is oriented with the base to the signal element, which is made roof-shaped and with a reflective coating from the bottom of the housing. and photo detectors and illuminators are installed

0 попарно в соседних гран х корпуса, причем плоскость расположени осей каждой пары перпендикул рна соответствующей грани сигнального злемента при его заданном положении .0 in pairs in adjacent faces of the housing, the plane of location of the axes of each pair is perpendicular to the corresponding face of the signal element at its specified position.

5 Введение второго излучател и форма выполнени корпуса датчика обеспечивают возможность компоновки оптических злементов в виде пар излучатель - фотоприемник , а выполнение сигнального злемента5 The introduction of the second radiator and the form of the sensor case provide the possibility of assembling optical elements in the form of pairs of emitter - photodetector, and the implementation of the signal element

0 крышеобразным и его расположение по отношению к корпусу гарантирует единственность пространственного положени контролируемого объекта (скрепленного с зтим злементом), при котором фотозлектри5 ческие сигналы уравниваютс ,0 is roof-shaped and its location relative to the body ensures the uniqueness of the spatial position of the object being monitored (bonded to this element), at which the photoelectric signals are equalized,

Крутизна зтих сигналов при прочих равных услови х в два раза выше, чем в известном датчике (где они пропорциональны площади освещаемого сегмента), и пропорAll other factors being equal, the steepness of these signals is twice as high as in the known sensor (where they are proportional to the area of the illuminated segment) and proportional to

0 циональна площади двух сегментов благодар наложению изобретени излучател на . приемную апертуру фотоприемника, в св зи с чем точность предлагаемого технического решени может быть вдвое выше, чем в из5 вестных датчиках.0 is the area of two segments due to the imposition of the invention of the radiator. the receiving aperture of the photodetector, in connection with which the accuracy of the proposed technical solution may be twice as high as in the well-known sensors.

Claims

The location of the radiators in the openings of the adjacent faces of the pyramid and their orientation in planes perpendicular to the faces of the signal element. eliminates the possibility of parasitic illumination of photodetectors outside a given position. This factor, together with the uniqueness of the position at which photoelectric signals are equalized (regardless of differences in the sensitivity of photodetectors), provides an increase in the sensor immunity. The right angle of the roof-shaped signal element in combination with the perpendicular installation of optical elements in the housing simplifies the design of the sensor and significantly improves its manufacturability. Figure 1 and 2 shows the variants of the sensor with the implementation of the signal element in the form of a groove or tooth, respectively, a general view. In case 1 (Fig. 1), two photoreceivers 2 and two emitters 3 are mounted in the holes, the optical axes of each pair of emitter photoreceivers are mutually perpendicular due to the fact that the planes of adjacent side faces of case 1 are perpendicular to each other. This condition is met when all edges of the pyramid are equal (without taking into account the truncation of the vertex). . The housing 1 is fixed motionless over the signal element 4 on the height-adjustable support 5. The height is determined by the size and shape of the signal element 4. The specific choice of the shape of element 4 is determined by structural amenities, for example, a groove can be made right in the body of the guide along which it moves controlled object, and the tooth - as a separate part. The sensor works as follows. When the controlled object is moving along a line perpendicular to the edge of the signal element 4, fixedly fixed, the photodetectors 2 are not illuminated until the signal element enters the zone close to the axis of the pyramidal body 1. At the same time, the light of the emitters 3 is reflected by the edges of the signal element 4 in the plane of incidence parallel to its edge. Depending on the distance a between the optical axes of the pair of emitter photodetector in the plane of the lower face of the pyramid and the distance b between the optical axes of the emitter 3 and photodetector 4 of the adjacent pairs, the height of the body above the signal element H is selected. 2If the diameters of the diaphragms of the emitters 3 and photodetectors 4 are the same, the signal at the output of each photodetector 4 changes in proportion to the doubled area of the illuminated segment of height I о I I Y1 2 S 2г2 (arcsin -4 1 1 - -), G where r is the radius aperture. High accuracy and noise immunity of monitoring the position of the object is achieved by increasing the height. In this case, the maxima of the signals Ui and U2 of the photoreceivers 4 mutually shift and equalize at a level of 0.75 Um - in the zone of greatest steepness. Then, in parallel, the signal Ua is subtracted from the signal Ui and added together. The resulting difference signal Uz is characterized in the zone of zero-crossing steepness, twice as large as the original Ui and Uz, with a rather steep increase along the edges. Due to this, a narrow pulse U4 can be formed when moving both in the right and in the opposite directions. The logical summation of the signals U and Us ensures the uniqueness of the position of the output signal. Thus, the combination of the proposed features provides, in comparison with the known sensor, an increase in the accuracy of control due to an increase in sensitivity by 4 times (using a difference signal) and noise immunity (due to self-synchronization by the total signal and the uniqueness of the signals for a given object position). In addition to the tag, the proposed sensor is distinguished by its simplicity of design due to the extremely simple form of the body and signal element and the ratio of their sizes. A photoelectric sensor, comprising a housing, an illuminator and photodetectors installed therein, a sensitive element for bonding with an object, and a recording unit, which is equipped with a second one in order to improve accuracy. the illuminator, the body is made in the form of an isosceles tetrahedral pyramid with openings for accommodating the illuminators and photodetectors and is oriented by the base to the sensing element, which is made roof-top and with a reflective coating on the side Novels of the case, and photodetectors and illuminators are installed in the adjacent faces of the case, the plane of location of the axes of each pair is perpendicular to the corresponding face of the sensitive element at its predetermined position.