SU903932A1 - Displacement-to-code converter - Google Patents

Description

The invention relates to automation and information-measuring equipment, in particular to photoelectric devices for measuring angular and linear movements.

A known angle converter is converted into a code comprising a code disc with a code track printed on it and a disk with reading slots attached to the shaft, light sources and photo detectors connected to the inputs of the processing device 1.

The disadvantage of this converter is a large number of code points up to rrzk at a high predetermined accuracy, which leads to an increase in size, a large number of photodetectors, also associated with an increase in accuracy, makes the converter expensive and causes additional difficulties in selecting photoreceivers with the same sensitivity. The disadvantages include the complexity of building a code disk with an information retrieval system, as well as the complexity of making code disks with acceptable points.

The closest technical solution to the proposed one is to move the code into the code.

containing an illuminator, an optical system,; a rotating I rectangular plate, the axis of rotation of which is fixed on the object under study and which is located between the illuminator and the photoreceiver, the output of which is connected through an amplifier to one input of the coincidence device, the second input of which is connected to the output of the generator,

10 and the output - with the input of the pulse counter. The position of the object with the axis of rotation of a rectangular plate fixed on it is a vessel t according to the duration of the darkening of the photodetector, and the specified duration depends on the distance between the axis of rotation of the plate and the axis of the light beam 2.

The disadvantage of the transducer is the nonlinearity of the change in the output signal, which reduces the measurement accuracy, and the impossibility of measuring the angular displacements.

The purpose of the invention is to improve the accuracy and expansion of the Functional

25 converter capabilities.

This goal is achieved by the fact that the transducer is moved, or to the code containing the illuminator, optical system, rectangular

30 plate, photodetector, the first output of which is connected via an amplifier to one input of a coincidence device, the other input of which is connected to the output of a pulse generator, and the output to a counter input, two inverters, three amplifiers, three coincidence devices and three counters, the axis of rotation of the rectangular plate is perpendicular to the optical axis of the converter, coincides with the axis of symmetry of the plate and is located between the illuminator and the optical system, and the photodetector is made four-phased, the second, third and fourth photon outputs the receiver is connected to the inputs of the second, third and fourth amplifiers, respectively, the outputs of the second and fourth amplifiers are connected to the inputs of inverters, the outputs of which are connected to the first inputs of the second and fourth, matching devices, the output of the third amplifier is connected to the first input of the third matching device, - the second inputs of the second , the third and fourth devices coincide with the generator output; the outputs of the second, third and fourth coincidence devices are connected to the inputs of the second, third and fourth th counters respectively.

FIG. 1 is a schematic of a movement converter in a code; Fig. 2 is a diagram of the change in pulse duration (there are no inverters); in fig. 3 - the same (inverters introduced).

The converter contains illuminator 1, rectangular plate 2, optical system 3, four-position photodetector 4; photocurrent amplifiers 5, two inverters 6, four coincidence units 7, an impulse generator 8 and four impulse counters 9.

FIG. Figure 1 (view A) shows the trajectory of the light spot from illuminator 1 in a plane perpendicular to the optical axis of the transducer, where the axis of rotation of plate 2 is located, as well as a photodetector with a light spot (view B).

The converter works as follows.

The illuminator 1 fixed on the object under study, when moving around the circumference, forms a light spot of large dimensions (size is due to the aberration of the optical system of the illuminator in a plane perpendicular to the optical axis of the converter where the axis of the plate 2 is located). When the object under study with the illuminator 1 is rotated at a certain angle T (Fig. 1, view A), the distance h between the center of the light spot and the axis of rotation of plate 2 changes in the expression h R –sin H

where R is the radius of the circle described by the optical axis of the illuminator 1. In turn, the duration of the pulse G is proportional to 2;

(arcsin-),

where w is the angular velocity of rotation of plate 2. Consequently, the pulse duration T is proportional to: 2 f 57. When the object is rotated at some angle f, the pulse duration

 vary linearly across the range. The light flux modulated by the plate 2 passes through the optical system 3, which fixes it in the plane of location

Photodetector 4, perpendicular

optical axis converter. Moreover, at the moment when the axis of the luminous flux intersects the axis of rotation of the plate 2, the light spot falls on one of the section of the photodetector 4

(the center of the photodetector 4 is aligned with the optical axis of the transducer), which makes it possible to combine the definition of the transition of the light spot every 90P with the reference point. Signal,

removed from the outputs of the photodetector 4, is amplified by amplifiers 5 of the photocurrent and is fed to the inputs of matching devices 7 connected to the generator of 8 pulses. Then from the output devices

7, the coincidence signal arrives at the pulse counters 9. Depending on the position of the light spot in the plane of the photodetector 4, the pulse is counted in one of the channels from O

up to 90 °. In the given case, the duration of the pulse T, depending on 4, will change in an inconvenient form to remove the reference. In one case, the origin coincides with the maximum value of t, in the other, with the minimum value (Fig. 2). In order for the origin in each channel to coincide in the pulse duration T (Fig. 3), in two channels between the output of the photocurrent amplifier 5 and the input of the device

7 matches the inverters are entered 6. The converter can also measure linear displacements of the object under study. In this case, two channels are used, and the light spot should

move in the plane of those photodetector pads 4 whose channels are used.

Such an embodiment of the converter allows to increase the accuracy, expand the functionality, avoid the use of complex in the manufacture of code disks and a large number of expensive photodetectors, which determines the economic efficiency of the proposed

devices.

Claims (2)

1. Authors certificate of the USSR 641484, cl. G 08, C 9/06, 1977. 2. Authors certificate of the USSR 255413, cl. G 08 C 9/06, 1968 (prototype). 90 a 180 270 f.a.