JPS6218850B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrical reference pulse generator for measuring the unbalanced angular position of a rotating body of the type in which detection scanning of marks is performed depending on the rotation of any rotating body having marks.

In the known device (DE 1103637), scanning pulses, such as needle pulses, are generated from a photoelectrically or electromagnetically scanned mark.
A reference pulse for measuring the unbalanced angular position is derived from this scanning pulse. It is therefore necessary to generate a rectangular wave voltage consisting of precisely shaped pulses and with little superimposition of harmonics. In the known photoelectric angular position generator (DE 11 03 639), a reference pulse is generated which makes it possible to measure unbalanced angular positions by scanning relatively narrow marks on a rotary body.

A disadvantage of the known devices for generating electrical reference pulses is that the accuracy of the generated pulses is influenced by the accuracy with which the scanned marks are applied on the same or different rotating bodies. A further disadvantage of this type of device is that it can only be used with scanned marks of narrow width. Furthermore, the known device has the disadvantage that it is not possible to detect and eliminate errors that lead to changes in the sharpness of the pulses, which are inevitable due to the aging of the photocells used, and thus to a deterioration in the accuracy of the generation of the reference signal.

For example, when a mark on a rotating body is scanned for the purpose of correcting the imbalance of a mass body, which is a mass-produced rotating body, errors occur in the signals generated by mark scanning due to the following reasons.

(1) For example, in the case of optical scanning, the signal generated by each mass (counterweight) mark will have a different height due to different reflection properties of the marks and due to aging and dirt of the photocell. An error occurs.

(2) In addition to the desired signal, an error occurs because an interfering signal appears, such as a small negative signal of the voltage U14 in FIG. 4, which will be described later.

(3) Due to the mechanical tolerances of the scanned mass (counterweight), the pulse width of each generated signal will be different, and the pulse width of each generated signal will be different, and the mass cannot be accurately positioned on the circumference. An error occurs because the point is determined to coincide with the side edge of the generated signal pulse.

In the prior art, scanning mark pulses were generated from an input signal resulting from mark scanning using fixed threshold values, and then the side edges of the scanning mark pulses thus generated were evaluated. If the threshold value is set to a high value, a relatively low input signal will not exceed this high value threshold due to cause (1) above, and therefore no output pulse will be generated. On the other hand, when the threshold is set to a low value, an output pulse is generated even if the input signal obtained from mark scanning is low, so a small negative disturbance pulse at voltage U14 mentioned in (2) above is input. Output pulses may occur even if the In the case of (3) above, an error occurs in the subsequent evaluation process of the side edges of the signal pulse, because this signal pulse does not accurately indicate a predetermined point on the circumference of the rotating body. .

The errors caused by the above-mentioned (1) and (2) are eliminated by the configuration of the pulse shaping circuit device 7 as set forth in claim 2. That is, it is removed by making the threshold value dependent on the maximum value (peak value) of the signal generated by mark scanning. This configuration allows automatic adaptation to the respective signal peak value and automatic suppression of low-value interfering pulses. The error caused by the above-mentioned (3) can be eliminated by the configuration described in claims 1 and 2, that is, by generating the output signal pulse at the center of the input signal pulse. This produces a negative edge of voltage U6 at the center of voltage U1, as shown in FIG. 2 below. This negative edge corresponds to a precisely positioned point on the circumference of the body of rotation to be scanned, even if the pulse widths of the respective pulses of voltage U1 have mutually different values.

The problem of the present invention is to balance the reproducibility of measurement results regardless of the mark to be detected, the accuracy with which the mark is placed on a rotating body, and the photoelectric or electromagnetic system used. The aim is to generate a reference pulse free of interference pulses that corresponds to the requirements of the technology.

According to the invention, the problem is solved by connecting the output side of the mark scanning device to the input side of the pulse shaping circuit device,
The output of the pulse shaping circuit arrangement is connected on the one hand via a rectifier to the signal input of an integrator and on the other hand to the input of a time stage, the first output of the time stage being connected to a control element for said integrator. and the output of the integrator is connected on the one hand via a switching element and a storage capacitor to the first input of the comparator and on the other hand to the second input of the comparator,
The problem is solved by extracting a reference pulse whose pulse starts rising at the center position of the output pulse signal of the pulse shaping circuit device from the output side of the comparator.

Furthermore, according to the invention, as a pulse shaping circuit device, a potentiometer is provided on one input side of the comparator device, which is capable of fixedly adjusting a portion of the peak value of the signal supplied from the mark scanning device via the input stage. Applying via a peak rectifier, the generator pulses are applied on the same input side as said one input side, without any waveform manipulation, and depending on the operation of the comparison device, only the scanning mark pulses are delivered on its output side. That's what I did.

As mentioned above, the known methods usually operate on the supply of needle-shaped pulses, which are formed by differentiating a signal generated, for example, from a pulse generator. Therefore, even if the signal of the pulse generator becomes contaminated due to dirt or deformation of the surface of the rotor of the oscillator, the removal of the disturbed pulses cannot be achieved. However, the present invention, for example, does not use this type of needle pulse, so the above-mentioned drawbacks do not occur. Further, according to the present invention, the width of the mark to be detected and the location of the transmitter relative to the rotor can be arbitrarily selected. That is, regardless of the rotational speed of the rotary body and regardless of the shape of the mark to be scanned or the position of the mark, it is possible to always generate an accurate reference mark by using a wide mark or a mark that is scanned in the tangential direction. Become.

Next, the present invention will be explained in detail using the illustrated embodiments.

As shown in FIG.
The scanning mark 3 is mounted on this rotating body.
is attached. This scanning mark 3 is, for example, a reflective strip or a mark with magnetic properties. This mark 3 is scanned by a mark scanning device comprising a lamp 4 and a photocell 5 in this embodiment. The device according to the invention can be used not only in the case of photoelectric scanning, but also in any scanning format.

An input stage 6 follows the mark scanning devices 4, 5, in which the signals generated by the scanning device are amplified and matched to a subsequent pulse shaping circuit arrangement 7. This pulse shaping circuit device 7 (this will be explained in detail in FIGS. 3 and 4)
In this case, the interfering pulses contained in the signals generated by the scanning devices 4, 5 and the input stage 6 are removed. This is therefore achieved by using a limit value whose height contained in this signal is switched depending on the maximum pulse. A scanning mark pulse is necessarily formed whose height in the signal supplied via the input stage 6 from the mark scanning device 4, 5 is controlled as a function of the maximum pulse. A precise square-wave voltage (U ₁ in FIG. 2) appears at the output 8 of the pulse-shaping circuit arrangement 7, and this square-wave voltage is supplied to a further circuit arrangement 101.

In this circuit arrangement 101, a rectangular voltage U ₁ is passed through an integrator 15 via a rectifier 9 and a resistor chain consisting of a series connection of bridgeable resistors 10 to 14.
supplied to Integrator 15 has an operational amplifier 16 that is negatively fed back via capacitor 17 . Capacitor 17 is short-circuited via switching transistor 18. The voltage at the output of the integrator 15 is fed via a further resistor 19 to an accumulator 20 . This accumulator 20 includes an operational amplifier 21, a storage capacitor 22, and a field effect transistor 23.
, a resistor 24, and a switching transistor 25
It consists of In a comparator stage 26 consisting of resistors 27, 28, 29, a portion of the voltage stored in the accumulator 20 is compared with the output voltage resulting from the next pulse of the integrator 15. If the two voltages are equal, a pulse is emitted via the amplifier 30 at the output 31 of the circuit arrangement. In the potentiometer 32, any possible zero point errors of the amplifier 30 are compensated.

For controlling the circuit arrangement 101, a monostable multivibrator 33 is used, which is connected to the output 8 of the pulse shaping circuit arrangement 7. An inversion circuit 34, which is connected to the flip-flop circuit 35 together with the output of the monostable multivibrator 33, is also connected to the output 8 of the pulse shaping circuit arrangement 7.

The inventive circuit arrangement 101 for generating an electrical reference pulse depending on the central position of the scanning mark pulse comprises:
It operates as follows; a precise rectangular voltage U ₁ (see FIG. 2) produced by the pulse shaping circuit arrangement 7 is supplied to the monostable multivibrator 33. At the end of each pulse of voltage U ₁ a pulse (U ₂ in FIG. 2) occurs at the output of monostable multivibrator 33.
A repetitive pulse occurs at the output of the flip-flop 35, the beginning of which is when the pulse produced by the monostable multivibrator 33 ends, and the end of which is when the pulse produced by the circuit arrangement 7 ends. This is when it began. This pulse train is shown as U ₃ in FIG. The square wave voltage generated by the circuit device 7 is applied to the circuit device 101.
is supplied to an integrator 15 via a rectifier 9 and resistor chains 10 to 14. At the beginning of each pulse, the switching transistor 18 is turned off, so that the negative voltage on the capacitor 17 of the integrator 15 increases linearly with time. At the end of the pulse, the rectifier 9 prevents further current flow. At the same time, the switching transistor 25 of the accumulator 20 becomes conductive via the monostable multivibrator 33, so that the voltage at the output of the integrator 15
be transferred into the . Using the operational amplifier 21, the accumulator voltage is sign inverted and its magnitude is inverted by the integrator 15.
becomes exactly equal to the output voltage of At the end of the pulse generated by the monostable multivibrator 33, the switching transistor 18 of the integrator 15 becomes conductive via the flip-flop 35, so that the capacitor 17 of the integrator 15 becomes conductive.
is discharged via the switching transistor 18. This erases the contents of the integrator 15. Therefore, on the output side of the integrator 15, as shown in FIG.
A voltage curve designated U ₄ occurs. Simultaneously, the monostable multivibrator 33 switches off the switching transistor 25 of the storage device 20, so that the value stored in the storage capacitor 22 remains.
The time course of the accumulated voltage is shown in FIG. 2 by U ₅ . Furthermore, the output signal of the integrator 15 is applied to a resistor 29 connected to the second input of the comparison stage 26 . The output voltage of the integrator 15 is then compared with the stored voltage across the resistors 27, 28 connected to the first input. Preferably, the resistors 27, 28, 29 are of equal size. When the integrator output voltage resulting from the next pulse reaches half the value of the accumulator voltage across the resistors 27, 28, a pulse is delivered via the amplifier 30 to the output 31 of the circuit arrangement 101.
Amplifier 30 operates as a switching amplifier without negative feedback, switching to a negative output voltage when the voltage at comparator stage 26 is zero. The voltage U ₁ produced by the pulse shaping circuit arrangement 7 has a completely rectangular waveform, so that the output voltage U ₄ of the integrator 15 increases exactly proportionally with time, so that the pulse shaping circuit arrangement 7 A negative-going pulse occurs at the output 31 of the circuit arrangement exactly at the moment when the center position of the generated square-wave voltage is reached. As shown in FIG. 2, in response to a change in the pulse width of the voltage U ₁ , following this change the output pulse U ₆ is generated at the appropriate time, i.e. in the middle of the square wave pulse generated by the pulse shaping circuit arrangement 7. arise.

When the contents of integrator 15 are eliminated via flip-flop 36 and switching transistor 18, only the voltage of accumulator 20 is still present at the input of switching amplifier 30. Therefore, the input voltage of switching amplifier 30 becomes positive and the output pulse ends.

For reasons of design of the components used, it is advantageous to select the storage voltage between +1 and +10V. This can be done by bridging parts of the resistor chains 10-14 via the jacks shown.

A circuit 7 will now be described which guarantees the elimination of disturbance voltages contained in the input signal by providing a switching limit which responds only to the highest pulses in the signal supplied by the pulse oscillator. 3-4 for a pulse shaping circuit arrangement 7 which generates scanning mark pulses in dependence on the pulse of maximum height in the signal supplied via the input stage 6 from the mark scanning devices 4, 5. I will explain using The disturbance voltage is superimposed on the voltage produced by the mark scanning device 4, 5, for example a photocell, so that in the steady state a voltage curve of the shape indicated by _U14 (see FIG. 4) results. Only the highest peak then depends on the scanned mark; the magnitude of the peak value varies within a wide range. The role of the pulse shaping circuit 7 is to form the scanning mark pulses in dependence on the maximum pulse height in the signals supplied via the input stage 6 from the mark scanning ranges 4, 5, so that the fault voltage is superimposed input voltage
The purpose is to generate an accurate square wave voltage from _U14 .

An embodiment of the pulse shaping circuit device 7 will be described with reference to FIGS. 3 and 4. Mark scanning device 4, 5
The signal U ₁₄ produced by the input stage 6 is fed via a potentiometer 87 and a resistor 88 to an operational amplifier 89 . This operational amplifier 89 is configured with two diodes 90, 91 and a resistor 92 into a peak value amplifier. capacitor 93
A negative peak voltage of opposite sign is accumulated at . The course of the voltage stored in capacitor 93 is shown in FIG. 4 at U ₁₅ . The voltage U ₁₅ applied to capacitor 93 is supplied to the input of switching amplifier 95 .
The input voltage U ₁₄ is applied to this same amplifier input via a resistor 96 of the same size, without waveform manipulation. When the sum of both voltages U ₁₄ and U ₁₅ changes its sign, the output voltage of the switching amplifier 95 changes its sign. A pulse voltage curve U ₁₆ therefore occurs. This voltage curve corresponds to the pulse voltage U ₁ .

In summary, as shown in FIG. 4, only the two pulses of maximum height in the input voltage U ₁₄ generate two corresponding pulses in the voltage curve U ₁₆ . However, a pulse of small height between the two maximum-height pulses at input voltage U ₁₄ does not generate a corresponding pulse in voltage curve U ₁₆ . Using potentiometer 87,
It is possible to adjust how many fractions of the peak value of the input voltage U ₁₄ the output pulses are to be sent.
In this case, only a corresponding portion of the peak voltage is stored in the capacitor 93 and an output signal is emitted. A scanning mark pulse U ₁ is thus generated depending on the pulse of maximum height in the signal supplied via the input means 6 from the mark scanning device 4 , 5 .

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a circuit arrangement for generating an electrical reference pulse depending on the center position of a scanning mark pulse;
FIG. 2 is a waveform diagram showing the voltage profile in the circuit arrangement of FIG. 1; FIG. FIG. 4 is a schematic circuit diagram of the generating pulse shaping circuit arrangement; FIG. 4 is a waveform diagram showing the voltage course in the circuit arrangement of FIG. 4, 5... Mark scanning device, 7... Pulse shaping circuit device, 9... Rectifier, 15... Integrator, 22
... Storage capacitor, 26 ... Comparison device, 33,
34, 35... Time stage.

Claims (1)

[Scope of Claims] 1. In an electrical reference pulse generator for measuring the unbalanced angular position of a rotating body, the mark scanning device 4, 5 is connected to the input of a pulse shaping circuit 7, the output of which is connected on the one hand via a rectifier 9 to the signal input of an integrator 15 and on the other hand the time stage 3.
3, 34, 35, the first output of the time stage is connected to the control element 18 for the integrator, and the output of the integrator is connected on the one hand via a switching element 25 and a storage capacitor 22. First
connected to a first input of the comparator 26 and, on the other hand, to a second input of the first comparator, such that the voltage applied to the second input reaches half the value of the voltage applied to the first input. Then, a reference pulse whose pulse starts rising at the center position of the output pulse signal of the pulse shaping circuit device is extracted from the output side of the first comparator. 2. In an electrical reference pulse generator for measuring the unbalanced angular position of a rotating body, the output sides of the mark scanning devices 4 and 5 are pulsed. The input side of the pulse shaping circuit arrangement 7 is connected, the output side of the pulse shaping circuit arrangement is connected on the one hand via a rectifier 9 to the signal input side of an integrator 15 and on the other hand the time stage 3.
3, 34, 35, the first output of the time stage is connected to the control element 18 for the integrator, and the output of the integrator is connected on the one hand via a switching element 25 and a storage capacitor 22. First
connected to a first input of the comparator 26 and on the other hand to a second input of the comparator, when the voltage applied to the second input reaches half the value of the voltage applied to the first input; A reference pulse whose pulse starts rising at the center position of the output pulse signal of the pulse shaping circuit device is taken out from the output side of the first comparator, and the second comparator is used as the pulse shaping circuit device 7.
A portion of the peak value of the signal supplied from the mark scanning devices 4, 5 via the input stage 6 is fixedly adjustable on one input side of the comparator 95 via a potentiometer 87 and a peak rectifier 89-91. In addition, the generator pulse is applied to the one input side without any waveform manipulation, and only the scanning mark pulse is sent to the output side depending on the operation of the second comparator 95. Electrical reference pulse generator.