SU1280317A1 - Device for controlling drive of dividing machine - Google Patents

Abstract

This invention relates to an instrumentation technique and is an improvement on a device according to the author. St. No. 998857. The purpose of the invention is to improve the accuracy by increasing the resolution of the division. The control unit of the drive of the dividing machine. On the 6-wedge-controlled inverter and trigger. When switching from one antinode to another in different cycles of operation of the dividing machine, the trigger 16 switches the inverter 14, thereby the polarity of the low-frequency oscillations taken from the output of the synchronous detector 15 has the same sign for different antinodes. This makes it possible to use the modes of operation with the miscalculation in each cycle of the dividing machine and an odd number of antinodes (including the first number), due to this, the division resolution is doubled. 2 Il. (L

Description

INJ

(pi / city /

112

The invention relates to measuring instrumentation and can be used in precision instrument making and machine building in the development of dividing machines for cutting diffraction gratings with interference control of fission and is an improvement of the device.

on auth. St. No. 998857.

The aim of the invention is to improve the accuracy by increasing the resolution of the division.

Fig, 1 shows a functional diagram of the device; FIG. 2 is a time diagram of signals input to and taken from the output of a synchronous detector,

The device contains a measuring scale 2 installed on the fixed part 1 of the dividing machine, an indicator scale 4 installed on the movable part 3 of the dividing machine, sources 5 and 6 of light connected in series by a photodetector 7, a detector 8, a unit 9 for motion counting, the output of which is connected to a control input drive 10 coarse movement. Drive 11 precise movement, multivibrator 12, the opposite outputs of which are connected to light sources 5 and 6, the key 13, the control input of which is connected to the output of block 9, and Discount input to the photodetector 7 controlled by an inverter 14 having an input connected to an output key. 13, and the output to the information input of the synchronous detector 15, trigger 16, whose input is connected to the output of the motion counting unit 9, and the outputs to the control inputs of the inverter 14, the control input of the synchronous detector 15, to one of the outputs of the multivibrator 12, and the output of the synchronous detector 15 with the input of the actuator 11 precise movement. In FIG. 2, the following symbols are adopted: envelopes 17 and 18 of the variable signal, which is fed to the input of the synchronous detector 15, corresponding to two raster gratings of the indicator scale; successive signal antinodes 19 and 20, corresponding to one interference moire band; reference points (nodes) 21 signals; low-frequency oscillations 22 of the same voltage sign, taken from the output of the synchronous detector 15, obtained with signal inversion172

la entering the input of the synchronous detector 15; low-frequency oscillations 23 of opposite voltage, obtained without inverting the input signal of the synchronous detector 15,

. The device works as follows.

Multivibrator 12 generates rectangular pulses in out-of-phase sources 5 and 6 of light

The measuring and indicator scales 2 and 4 form a raster junction, which, when moving the movable part 3 of the dividing machine relative to its fixed part 1, modulates the light fluxes generated by the sources 5 and 6 of light.

Due to the mutual shift of the raster gratings plotted on the indicator scale 4 by an amount equal to half the price of the moire strips formed by the rasters, the electrical signals taken from the photodetector 7 contain two envelopes 17 and 18 (FIG. 2a), shifted relative to each other by 180 ° The frequencies of the carrier signals of the signals generated by the envelopes are determined by the frequency and phase of the signals formed by the multivibrator 12. The device is based on the principle that each interference moire band during its passage forms two antinodes (for example, 19-20) of a differential variable photoelectric signal, phase carrier frequency oscillations for which with respect to the oscillation phase of the multivibrator 12 also differs by,

The signal fuzziness is detected modulo by detector 8, the output of which is fed to the input of the displacement count unit 9. After the moving part 3 of the dividing machine is moved by the drive 10 gross movements for a predetermined distance, a signal is generated at the output of the movement counting unit 9, which turns off the rough movement drive 10 and turns on the (opening) key 13. The output signal from the photodetector 7 goes through the key 13, the inverter 14 information input of the synchronous detector 15,

The reference signal to the control input of the synchronous detector I5 comes from the output of the multivibrator 12, Synchronous detector 15 performs 31 synchronous (phase-sensitive) detection of the envelopes of the signal removed from the photodetector 7. The synchronous detector is turned on (by opening the key 13) near points 21, which amplitudes of the envelopes 17 and 18 are close to each other so that the amplitude of the variable difference signal is zero (signal nodes 21). Drift displacements of the movable part 3 of the dividing machine lead to a change in the voltage taken from the output of the synchronous detector 15. In turn, these voltage changes applied to the input of the drive-AND exact movement cause it to trigger, correcting the position of the movable part in periods streak diffraction grating. When moving from one antinode 19 to another 20 in different cycles of the dividing machine, the phase of the carrier oscillations changes by 180. However, the trigger 16 under the action of signals coming from the output of the block from the account of the movements to its input, after the end of each cycle of the machine’s operation, switches the inverter 14. Due to this, the phase of the variable signals entering the information inputs of the synchronous detector 15 remains unchanged regardless of Which of the successive antinodes of signal 17 .4 passes at a given time. Accordingly, the sign of the low frequency oscillations 22 remains constant for different antinodes. The drive 11 of the exact movement is triggered in each cycle; no periodic division errors occur. The price of each antinode is / 2, i.e. half of the interference moire band. When calculating} in one cycle, the m m of the indicated antinodes of the signal p d / number of strokes per 1 mm of the cut gratings is determined by the relation where µm / 6 µm is the discreteness of the system of measuring grids. Formula of the invention The control unit for the drive of the dividing machine according to ed. St. No. 998857, characterized in that, in order to improve accuracy by increasing the discreteness of the division, a controllable inverter and a trigger are added to it, the inverter input is connected to the output of the key, the output is connected to the input of the synchronous detector, the control inputs are connected to the outputs trigger, the input of which is connected to the output of the block of movement displacement.

Claims (1)

The claims are not which of the antinodes of the signal The control device of the drive of the dividing machine according to ed. St. No. 998857, characterized in that, in order to increase accuracy by increasing the resolution of division, an additional inverter and a trigger are introduced into it, while the inverter input is connected to the key output, the output to the synchronous detector input, the control inputs are connected to the trigger outputs, the input of which is connected to the output of the move block. VNIIIPI Order 7047/39 Circulation 670 ________ Signed Custom polygr. ave, city of Uzhhorod, st. Project, 4