SU1695502A1 - Shaft angle encoder - Google Patents

Abstract

The invention relates to automation and computing and can be used to automatically measure angular movements. The aim of the invention is to increase the speed of the converter by introducing a parallel change in the state of analog switches by impulse at one of the inputs of the counter. The goal is achieved in that a known angle-code converter containing a sine-cosine sensor 1 angle, inverters 3 and 4, analog switch 5, voltage divider 7, two comparators 10 and 11, element 12, elements 13 and 15 , delay element 19, D-trigger 18-1, generator of 14 rectangular pulses, three analog switches 6.8 and 9, the second D-trigger 18-2, two reversible counters 16 and 17 are introduced. The introduction of additional elements makes it possible to eliminate redundancy switching and thereby increase the speed of the converter. 2 Il. J

Description

The invention relates to automation and computing and can be used to automatically measure angular movements.

The aim of the invention is to increase the speed of the converter by changing the state of the switches in parallel to the pulse at one of the inputs of the counter.

Figure 1 shows a block diagram of a converter; figure 2 - diagram of the Converter.

The converter contains a sine-cosine angle sensor 1 with a sine 21 and a cosine 22 outputs, inverters 3,4, first analog switch 5, second analog switch 6, voltage divider 7, third and fourth analog switches 8 and 9, first and second comparators 10 and 11, element 12, element 13, rectangular impulse generator 14, element 15, first and second reversible counters 16 and 17, first and second D-flip-flops 18, delay element 19.

The Converter operates as follows.

When the object (shaft) is rotated at an angle of fna with the outputs 2.1 and 2.2 of sensor 1, signals are generated that are proportional to (or close to) sin ip and cos p. Figure 2 above shows the signals from sensor 1, as well as the signals at the outputs of inverters 3 and 4, depending on the angle of rotation p.

Suppose that at first the shaft is stationary, and the codes at the address inputs of the switches 6,5,8 and 9 are such that when their information inputs switch, the threshold levels at the first and second inputs are respectively

ABOUT

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the comparators 11 and 10 with respect to the reference signal from the output of the switch 6 provide the signals of the log. O at the outputs of the comparators 10 and 11, i.e. the reference level is between the lower and upper thresholds of the comparators 11 and 10. At the same time, with the help of D-flip-flops 18, the elements 13 and 15 are locked and the counter 16 does not change its contents. Such a state of the transducer at a given constant shaft position is stable.

Suppose also that in this initial state of the transducer the shaft turn corresponds to a certain angle (Fig. 2a), and the output of the counter 16 contains a zero code. The reference signal for comparators 10.11, generated by switch 6 with a zero code at its address input, is proportional to sin p0, since the first information input of switch 6 is connected to the output. The output signal of switch 5 used to form threshold levels for comparators 10 and 11, proportional - cos po (the first information input of the switch 5 is activated). The signal from the output of the switch 5 is fed to the input of the voltage divider 7, the division ratio Kp of the n-th channel of which for the considered case of harmonic signals is calculated by the formula

 - (5-n), where n 1-4,

which is obtained from the condition of uniformity of the discretization step on the angle p, In the considered case of harmonic signals, the lower threshold (the signal applied to the first input of the Comparator 11) is -Ki-cosЈ o - cos po, and the upper threshold (the signal at the first input of the comparator 10) is -K2 cos ro - 0.67 cos p0. The required Kp coefficients are provided in order to connect the information inputs of the switches 8 and 9 to the outputs of the divider 7 (see FIG. 1), and the choice of the required functional dependencies for ro to connect the information inputs of the switches 5 and 6.

In Figure 2a, the lower and upper thresholds corresponding to this one are depicted by lines A and B, respectively, while the reference level (sin po) is between these thresholds. In this case, as noted, the comparators 10.11 form signals log.0, the elements 13 and 15 are locked, and the pulses of the generator 14 do not pass to the counting inputs of the counter 16. Thus, as long as the shaft is stationary ((p o) The state of the counter 16 does not change.

As the shaft moves, the reference and threshold signals change according to the corresponding functional dependencies. As long as the reference signal is in between. horns, the contents of the counter 16 is not changed. The situation is disturbed when the reference signal crosses one of the threshold signals. For example, when moving from p0 to the right in FIG. 2a, the reference level at a certain angle

0

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0

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p exceeds the upper threshold level, the AND 13 element is locked and the pulse from the generator 14 through the AND 15 element is allowed to the first input of the counter 16, and the code at the output of the counter 16 is increased by one in the lower order, which leads to a change in the state of the switches 8 and 9: the second information inputs are connected to their outputs, which means changing the threshold signals on the second and first inputs of the Comparators 10 and 11, respectively. From this point on, the signal level on the second input of the comparator 10 is proportional to -Cs cos (p, and on the first to The comparator 11 -Ka cos p ode. After the completion of the switching, the output of the switches 10 and 11 again has a log O, which locks the elements 13 and 15, since the reference signal from the output of the switch 6 again appears between the threshold signals from the outputs of the switches 8 and 9. The converter returned to the steady state (waiting for the difference between the threshold and the reference signal to change), the counter 17 fixed the angle increment (its contents increased by one).

Upon further movement of the shaft in the same direction, the state of the converter (t, e, the contents of the counters 16 and switching) changes in accordance with the table in Fig. 2, b, showing in what order the signals from outputs 2.1 and 2.2 switch with increasing counter code 16.

When moving to the right of p0, the reference level successively crosses the upper thresholds. At first, the contents of counter 16 are changed only in two lower bits (codes 0, 1, 2 or 3), each such code corresponds to a certain state of switches 8 and 9, changing the thresholds of comparators 11 and 10, the division ratio of the threshold signal, input divider 7. When increasing the contents of counter 16 (starting with 4), the sign of the reference signal from the switch 6 output (the signal from sensor 1 becomes positive) changes, which makes it necessary to change the threshold signal performed by activating the second input comm ora 5 (the input of the divider 7 TE0

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0

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The signal is proportional to cos p).

Upon further movement of the shaft, the contents of the counter 16 change sequentially in the range, with only the threshold signals changing, but with a new signal at the input of the divider 7.

Starting with the counter code 16, equal to 8, a new reference signal is used — cos p which is present at the output of switch 6 before the code appears on counter 16, equal to 15. The switching cycle of threshold signals and the selection of division factors is similar to the previous cycle (codes 8). Starting with a code on counter 16 equal to 16, the new reference function is again selected equal to (- sin p), and the cycle of selection of threshold signals and division factors is resumed; Starting with code 24, the cos p reference function is selected with analog switch commutations 5,8,9. When the counter 16 overflows and further moves in the same direction, the latter is reset, and then all the commutations are periodically repeated.

When the shaft moves backward, the operation of the converter is similar to the considered case, while the contents of counter 16, when the reference signal crosses the lower threshold, is reduced by 1.

Claims (1)

Invention Formula Angle-code converter containing a sine-cosine angle sensor, the outputs of which are connected respectively to the first and second inputs of the first analog switch, two inverters, a voltage divider, two comparators, two And elements, a square pulse generator, a NO element, a D-trigger , a delay element, characterized in that, in order to increase the speed of the transducers, the second, third and fourth analog switches, the second D-flip-flop and two reversible counters are introduced into it, the sinus output of the sine cosine date The angle is connected to the input of the first inverter, with the third information input of the first and the first information input of the second analog switches, the cosine output of the sine-cosine angle sensor is connected to the input of the second inverter, with the fourth information input of the second analog switches, the output of the first inverter is connected to the fifth and sixth information inputs of the first and third information inputs of the second analog switches, the output of the second inverter is connected to the first and fourth information inputs of the second analog switches, the fifth, sixth, seventh and eighth information inputs of the second analog switch are connected to the common bus, the output of the first analog switch is connected to the input of the voltage divider, the first output of which is connected to the first information switches. the inputs of the third and fourth analog switches, the second output of the voltage divider is connected to the second and third information inputs of the third and fourth analogs x switches, the fourth and fifth information inputs of which are connected to the third output of the voltage divider, the fourth output of which is connected to the sixth and seventh information inputs of the third and fourth analog switches, the eighth information inputs of which are connected to the common bus, the output of the second analog switch is connected to the first the inputs of the first and second comparators, the output of the third analog switch is connected to the second input of the second comparator, the output of the fourth analog switch connects It is connected to the second input of the first comparator, the output of which is connected to the D-input of the first D-flip-flop, whose C-input is combined with the C-input of the second D-flip-flop and connected to the output of the square pulse generator, which is connected via the delay element to the first input of the first and the second element And, the output of the second comparator is connected to the D-input of the second D-flip-flop, the output of the first D-flip-flop is connected to the second input of the first And element and through the element NOT to the second input of the second And element, the third input of which is connected to the output of the second D- trigger a, the output of the first element I is connected to the summing inputs of the first and second reversible counters, the subtraction inputs of which are connected to the output of the second element I, the outputs of the first, second and third bits of the first reversible counter are connected to groups of address inputs of the third and fourth analog switches, the outputs of the third the fourth and fifth bits of the first reversible counter are connected to the group of address inputs of the first analog switch, the outputs of the fourth and fifth bits of the first reversible counter connected to trupG mauTaetS "NrYaH SK Gogo on rGrGG 2ST pre 6ra3 ° ° -sin SC sixteen) f eight I KVP® with 04 SN tftf "M V.K "but -before W / -sin r tlni sin G -cosf FIG. 2 -cos -cosf - sin stof -sin cesf I I § I