RU25219U1 - ANGULAR MOVEMENT CONVERTER - Google Patents

Abstract

An angular displacement transducer comprising a movable system of a code limb rigidly fixed on the shaft with strokes unevenly applied on its diameter, an information reading system consisting of a sequentially located radiation source, a condenser, a linear photodetector and an electronic unit, characterized in that it is equipped with a unit comparison, the inputs of which are connected with the outputs of the electronic unit, and on the code dial concentrically with the first plotted the second track with strokes, the angular distance between which is constantly located between a fixed raster with four groups of strokes applied on it, shifted relative to each other by a quarter of the angular distance between the strokes and four lenses glued to it, the focus of each of which has a radiation source, and the receiving lens, in the focus of which is installed radiation receiver, the outputs of which are connected to the inputs of the electronic unit.

Description

ANGULAR MOVEMENT CONVERTER

The proposed utility model relates to the field of optoelectronic instrumentation, namely, to devices for measuring the angular position and moving objects.

A device is known - an analogue for measuring angular displacements 1, containing a movable system consisting of a shaft with a code dial rigidly fixed to it. The limb is a glass base coated with concentric code tracks with transparent and opaque segments. The information reading system includes an irradiating unit consisting of a radiation source and a condenser. Sensing unit - photodetector made in conjunction with a slotted diaphragm. Electronic circuits containing amplifiers and discriminators of signal levels are mounted in the converter housing.

The main disadvantage of this device is the complexity of manufacturing code limbs and the associated high complexity. In addition, a disadvantage of the known device is the inability to determine the angular position of the object with high resolution, as well as the inability to restore information with each polling cycle.

Closest to the proposed utility model in technical essence is the angular displacement transducer 2, comprising a movable system consisting of a code limb rigidly fixed to the shaft, an information reading system consisting of a sequentially located radiation source, a condenser, and a photodetector in the form of a multi-element linear-type image receiver the photosensitive surface of which is located in a plane parallel to the surface of the code limb, and the electronic unit, the input otorrhea connected to the output of the photodetector device. In this case, the code limb is made in such a way that the angular distance between adjacent strokes is determined by the dependence: where Ф (п-1) .п Фо. 1 + Y «(n-l), фо, 1 - angular distance between the zero and first strokes; y is a constant angular value that exceeds the error in determining the angle between adjacent strokes; n 1, 2, 3 ... - the serial number of the strokes applied on the limb, with the exception of zero, while:

(R, + 9 (.- mp.

The main disadvantage of the prototype is the inability to have constant information about the magnitude of the movement of the object with sufficiently high accuracy at high angular speeds of rotation of the object (up to tens of revolutions per second). It is difficult to integrate such devices into automatic control systems for the measurement process; they successfully operate in open systems.

In addition, obtaining high accuracy (up to units of arc seconds) is also fraught with great difficulties, because it is necessary to carry out a linear piecewise approximation of the readings taken from a multi-element receiver of a linear type, which has significant non-linearity.

The main objectives of the proposed utility model is to expand the functionality associated with ensuring reliable operation at high angular speeds of rotation of the object, and, as a result, the ability to work in closed systems for automatic control of the measurement process, as well as simplifying the operation of certification of a multi-element receiver of a linear type.

To solve this problem, an angular displacement transducer is proposed, which comprises a movable system consisting of a code limb rigidly fixed on the shaft with strokes unevenly applied on its diameter, an information reading system consisting of a sequentially located radiation source, a condenser, a linear photodetector, and electronic unit.

However, unlike the prototype, the second track with strokes, the angular distance between which is constant, is plotted concentrically from the first on the code limb. This track is located between a stationary raster with four groups of strokes applied on it, shifted relative to each other by a quarter of the angular distance between the strokes, and four lenses glued onto it, at the focus of each of which a radiation source is installed, and a receiving lens, in the focus of which the receiver is mounted radiation. The outputs of the linear-type photodetector and radiation receiver are connected to the inputs of the electronic unit, the outputs of which are connected to the inputs of the comparison unit.

The essence of the utility model lies in the fact that due to the presence of an additional track and an appropriate reading system, information is provided at large angular speed of rotation of the dial (up to tens of revolutions per second), and the comparison unit, simplifying the operation of attesting a receiver of a linear type, makes the right choice of low-order units .

The principle of operation of the proposed angular displacement transducer is illustrated by the drawings and the application.

In FIG. 1 is a circuit diagram of an angular displacement transducer; FIG. 2 - view A (on the limb) in FIG. 1, the appendix shows a table with an example of applying strokes on the limb.

The angular displacement transducer (Fig. 1) contains a radiation source 1, a condenser 2, a code limb 3, a linear photodetector 4, a radiation source 5 (in the amount of four), lenses 6 (in the amount of four), raster 7, a receiving lens 8, a radiation receiver 9 (usually a photodiode), an electronic unit 10 and a comparison unit 11. In FIG. 2 designations are the same as in FIG. 1, in addition, strokes 12 are plotted on track 13 (Di), the pitch between which is uneven, bars 14, plotted on track 15 (D2), the pitch between which is constant, the photosensitive elements 16 of the photodetector 4 of a linear type, as well as the photosensitive element 17, taken as a benchmark.

ccamu-i

The device operates as follows:

The radiation source 1 (Fig. 1) with a capacitor 2 illuminates the dashes 12 (Fig. 2), deposited on the surface of the code limb 3 (track diameter DI). Their shadow image is formed on the photosensitive elements 16 of the multi-element image receiver 4 (Fig. 1), one of the elements of which, for example, 17 was taken as a reference. In the photodetector 4, the spatial arrangement of the images of the bars is converted into a time sequence of amplitude-modulated video pulses, the mutual temporal position of which clearly corresponds to the distance between the 16 strokes projected onto the photosensitive elements. In the electronic unit, the angular distances between the dashes are calculated.

Let, for example, on limb 3 (Fig. 2), the angular distances between adjacent strokes are determined by the dependence S (ni), „- So, -i + у (n - 1), while the angular distance between the zero and first strokes SQ, i 12, a constant value of 0.75 (45), and n 225 (zero and 225th strokes coincide). The radius on which the strokes are applied is Di / 2. Then, in accordance with the above dependence, you can compile table 1 (see. Appendix).

Let the photosensitive element 17, taken as a benchmark, be between strokes No. 6 and No. 7. The entire table is located in the storage device of the electronic unit 10 (Fig. 1). Since the time sequence of the amplitude-modulated video pulses generated in the linear type photodetector 4 unambiguously corresponds to the linear distance between the strokes of the limb, the distance bb, p between the center of the stroke 6 (Fig. 2) and the center of the reference photosensitive element 17 (p) and the distance are easily calculated Bb, between the centers of strokes 6 and 7.

From the linear distance bb.y, the angular distance Sg.y between the strokes is determined:

i (i € dma

According to the angular distance 8b, 7, the angular distance So.6 between the zero and sixth strokes (Table 1) is taken from the memory and the angular position C of the object is determined (see Fig. 2):

With So, 6 + arctg (2. L6, p / Di)

Let, for example, D 110m, and Lb, p 0.135mm.

Then C 83.25 + arctan (2 0.135 / 110) 83.25 + 8.45 91.7 1 ° 31 42.

Simultaneously with the above-described channel for obtaining information about the angular position of the object, another channel also works, namely: -5 radiation sources, each of which is in the focus of its lens 6, irradiate them with light modulated at a certain frequency. Moreover, each irradiation is shifted relative to each other by a quarter of the period. From the lenses 6 come out parallel beams of light irradiating the raster 7, on which groups of strokes are applied against each lens, having the same step as the strokes applied on track 15. These groups are shifted relative to each other by a quarter of the angular step. The receiving lens 8 collects all parallel beams that have passed the raster 7 and limb 3 and focuses them on the photosensitive surface of the radiation receiver 9. As a result, the signal recorded from the radiation receiver 9 will look like:

. J Jo cos (cot - 9),

Where Jo is the amplitude of the variable signal, the value of which depends on a number of parameters of specific optical and electrical circuits of the converter.

9 - signal phase, depending on the relative position of the movable dial 3

relative to raster 7.

When limb 3 is rotated by one angular step, phase 9 changes by 2 tf. For example, if 21,600 strokes are applied to track 15, then one step is equal to 1 minute of arc (60). Thus, the phase of the signal will change by 2 ts when the dial 3 is rotated by an angle equal to 60. When the dial is rotated by one arc second (1), the phase of the signal will change by six electrical degrees (6 °). In

As a result, information on the rotation of the limb 3 with a resolution of 1 can easily be taken on this channel. When the power is removed and then turned on again, information on the position of the limb within one step will be saved.

So, suppose we took information about the position of the limb from two channels. For example, in the first of the described channels, we obtained 1 ° ЗГ 42, and in the second, 48. The comparison unit compares these data and gives the final result: the angle of rotation of limb 3 is 1 ° 3 Г 48.

The fact is that the second of the described channels works on a large number of strokes and is more accurate. If, for example, on the first channel we get the result 37 ° 15 3, and on the second 52, then finally the comparison unit will give the result 37 ° 14 52. That is, the comparison unit, taking into account the error of operation of the coarser and more accurate channels, will either add G, or decrease G, or save the value of minutes issued on the first channel to the readings. The value of seconds will always be taken over the exact channel.

Thus, the proposed angular displacement transducer, designed to measure the rotation angles and the angular position of the object, unlike the prototype, allows you to work with high resolution at high speeds (tens of revolutions per second). In addition, the need for very accurate certification of a linear-type photodetector, which is also a sushi, a significant advantage of the proposed device, disappears.

SOURCES OF INFORMATION

1.l.i. Presnukhin et al.: “Photoelectric information converters. M. Engineering. 1974, p. 298-299 (equivalent)

2. Patent No. 2120105, priority dated 11.06.96, published on 10.10.98 (prototype).

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Claims (1)

An angular displacement transducer comprising a movable system of a code limb rigidly fixed on the shaft with strokes unevenly applied on its diameter, an information reading system consisting of a sequentially located radiation source, a condenser, a linear photodetector and an electronic unit, characterized in that it is equipped with a unit comparison, the inputs of which are connected with the outputs of the electronic unit, and on the code dial concentrically with the first plotted the second track with strokes, the angular distance between which is constantly located between a fixed raster with four groups of strokes applied on it, shifted relative to each other by a quarter of the angular distance between the strokes and four lenses glued to it, the focus of each of which has a radiation source, and the receiving lens, in the focus of which is installed radiation receiver, the outputs of which are connected to the inputs of the electronic unit.