SU1424123A1 - Shaft angle digitizing method - Google Patents

Abstract

The invention relates to automation and computing technology and can be used in software systems for controlling machine tools, optical control systems and radio telescopes. The aim of the invention is to improve the accuracy of the method of converting the angle of rotation of the shaft into a code. To do this, in the method of converting the shaft rotation angle, based on converting the shaft rotation angle into two analog signals, generating the signal of the first bit of the output code, generating a logical signal, generating the signal of the second bit of the output code, converting the magnitude of the first analog signal into the signals of the remaining bits output code, the first analog signal is inverted and its value is converted into signals of the remaining bits of the output code in the interval of shaft rotation angles from 90 to 180 ° and from 270 to 360 °, and the value of the analog signal is converted into signals of the remaining bits of the output code in the interval of angles of rotation of the shaft from 0 to 90 ° and from 180 to 270 °. 2 Il. cl

Description

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The invention relates to automaton and computer technology and can be used in software systems for controlling machine tools, optical control systems and radio telescopes.

The aim of the invention is to improve the accuracy of the method of converting the angle of rotation of the shaft into a code.

FIG. 1 shows a block diagram of a converter that implements a method for converting an angle of rotation of a shaft into a code; in fig. 2 - diagrams, according to the principle of its operation.

The converter contains measuring disk 1, indicator disk 2, radiation source 3, sensitive elements 4-7, differential amplifiers 8, 9, inverting amplifier 10, switch 11, comparator 12, analog-1 converter (ADC) .13, adjustable sources 14, 15 voltages, the switch 16, the comparator 17 and the adder 18 modulo two.

The measuring disk 1 contains a J3 measuring track, which is a uniform transparent and opaque areas with a step W. On the indicator disk 2, in front of the sensitive elements, the slits are shifted relative to each other by an angular value W (n + 1/4), where - integer.

The converter realizing the preposition1.11 method works as follows.

When the measuring disk 1 moves relative to the indicator suit 2, the radiation, 1 above the source 3, modulated by the measuring track and the slits, falls on the sensitive elements 4-7, the outputs of which are shaped by triangular electric signals shifted from each other by 90 °, on b1; :: odeh sensitive, Ex elements 4, Hi, 6 form antiphase signals of triangular forms.

The signals from the outputs of the sensing elements 4-7 are fed to the inputs of differential amplifiers 8, 9i at the outputs of which are formed symmetrical about zero analog signals C, Uj, shifted relative to each other by an angle close to 90 (Fig. 2a), the signal U with help

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With the inverter amplifier 10 is converted into antiphase.

The direct and inverting signals from the outputs of the differential 8 and inverting 10 amplifiers arrive at the inputs of the switch 11, to the control input of which the first bit of the output code generated by comparator 12 is received by comparing the signal C with a zero level (Fig. 2b) . The switch 11 is controlled in such a way that its output passes a signal of only positive polarity (Fig. 2c), which is fed to the input of the A / D converter 13, at the output of which a code proportional to the input voltage is generated.

Due to technological errors in the manufacture of the indicator disk 2 and the inaccuracy of its adjustment, the phase shift between the signals U, and. is different from 90 ° and has an error ((Fig. 2a), which accordingly leads to a conversion error. Therefore, at angles equal to 90 °, the values of the signal and (Ulj and Uj) and the adjustment of sources 14, 15 are determined on their outputs set voltage equal to

and and (Fig. 2 a), respectively, which are fed to the inputs of the switch 16, to the control wrap of which the first discharge of the trick goes: g, code. The switch 16 is controlled in such a way that when the control input of an O code (i.e. for U value, 70) is applied, the KoivfMyTaTopa 16 output passes voltage, and if there is 1 code (i.e. for U value , 0) the output of the switch 16 passes the voltage U (Fig. 2 g ;,

The signals from the outputs of the differential amplifier 9 and switch 16 receive PS-. the inputs of the comparator 17, the output of which is a formrus-tc; togic signal (fig. 2d) by comparing the signal and with the voltage U at the code value of the first digit O and by cpaBHeifflH Jo with the voltage: -beacom U at the code value of the first discharge Yes .

As can be seen from the diagram (Fig. 2 d), the operation of the comparator 17 occurs strictly at 90 and 270.

Logic signals from BODYCASTERs of the parators 12, 17 are fed to an adder 18 modulo two, the output of which forms the second discharge output

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code (Fig. 2 e), arriving at the control of the input of the ADC 13.

Since in the range of angles 90–180, 270–360 °, the triangular signal at the input of the ADC 13 (Fig. 2c) decreases, so that the output code of the converter increases linearly when the measuring disk 1 moves by one step, in this range of angles The code for the ADC 13 must be inverted. Therefore, the ADC 13 is controlled in such a way that when the O code is present at the control input, then the direct code passes the output of the ADC 13, when code 1 is present at the control input, then the inverted code passes the output of the ADC 13

Claims (1)

Invention Formula The method of converting the angle of rotation of the shaft into a code based on the conversion of the angle of rotation of the shaft p two analog signals, the period of which is equal to the quantization step of the angles of rotation of the shaft and which are out of phase relative to each other by an angle close to iF / l, simultaneously inverting the first analog 234 the first signal of the output code by comparing the magnitude of the first analog signal with a zero level, the formation of a logical signal, the formation of a signal of the second discharge of the output code by summing modulo two signals of the first bit of the output code with a logical signal, characterized in that In order to improve the accuracy of the method, in it a logical signal is formed by comparing the magnitude of the second analog signal with the value of the second analog signal at the moments when the phase ne analog signal equal to and 3/2, convert the first analog signal in the phase intervals from O to gG / 2 and from F to C / in the signals of the remaining bits of the output code, and in the remaining intervals of the phase of the first analog signal in the remaining bits the output code converts the inverted first analog signal by inverting the direct code corresponding to the value of the inverted first analog signal. .f tpujt. one a.2