SU1706836A1 - Device for compensating tooling errors of metal-cutting machines - Google Patents

Abstract

The invention relates to instrumentation and can be used to compensate for errors in the machining of parts on machine tools with numerical control (CNC) under the conditions of flexible automatic production (HAP). The purpose of the invention is to improve measurement accuracy and enhance functional capabilities. The invention relates to an instrument for metal machine tools and can be used in the machine tool to compensate for errors in the machining of parts on machine tools with numerical software control (CNC) in the conditions of flexible automated production of LAPs. The purpose of the invention is to improve the measurement accuracy by introducing a source of coherent radiation, device residues. The device contains an anomorphous optical system, providing a coherent radiation source located in the front focal plane of a spherical collimating lens, behind which a first cylindrical lens is installed. and E. its rear focal plane is an additional supporting half-plane, which coincides with the front focal plane of the second cylindrical lens. The second cylindrical lens is installed in the front horizontal plane of the projecting lens, behind which it is split (cf. tdrite cube, for the first ... Ng. Which is reflected along the way, a flat incidental mirror is established by radiation, and a spherical concave reflector is located along the transmitted beam during the second period, focusing the field. -T,: iHne to The second is matched by the condition;;, .... (Gauss alignments with distance to the rear and focal plane of the lens and distance from the receiver; 17 with a charge connection or a special measuring slit and expanding the functional capabilities of the device due to the fact that the range of diameters of the tested parts is expanded due to the introduction of a supporting half-plane, statically located in the optical-optical system, as well as due to the design of the device as for the dimensions of obr; -ttyzaemy det.- (L o o: oo with O /

Description

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and the state (of the nose) of the tool cutting edge and its position in the machine coordinate system.

The location of the known coherent radiation source in the front focal plane of the known first spherical lens, behind which the first cylindrical lens is located, allowed to obtain a focused light beam in the form of an elongated ellipse, in which two coaxially distributed beams are concentrically located on the front face of the controlled cutting tool. The first beam propagates around the optical axis in the angular cone and is the coherent radiation of the source. Spontaneous radiation propagates in the angular cone of 90 ° outside this cone. This arrangement of the elements allowed the illumination of the measuring slit formed by the tip of the cutting wedge.

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focal mirror whose focal distance is matched by a Gauss focusing condition with a distance between the back focal plane of the known projection lens and a concave spherical mirror, as well as the distance between the concave spherical mirror and the known receiver with

Y link in the course of the light beam through the beam splitting cube

Figure 1 shows the layout of the optical system and the course of the rays in the sagittal plane; figure 2 - scheme opt

15 of the system and the course of the rays in the meridian plane; FIG. 3 is a diagram of the optical system of Fourier transform, its scaling and projecting a linear image of the

2Q slit on receiver with charge connection; in FIG. k, a photograph of the linear image of the measuring pin; figure 5 photograph of the diffraction image of the measuring slit

tool and additionally introduced 25 in Fig.6 - photograph of the video signal

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focal mirror whose focal length is matched by the Gauss focusing condition with the distance between the back focal plane of the known projection lens and the concave spherical mirror, as well as the distance between the concave spherical mirror and the well-known receiver with a close link along the beam of light through the beam-splitting cube0

Figure 1 shows a diagram of the optical system and the course of rays in the sagittal plane; Fig. 2 is a diagram of the optical system and the course of the rays in the meridian plane; Fig. 3 is a diagram of the optical system of the Fourier transform, its scaling and projecting the linear image of the measuring gap on the receiver with charge coupling; FIG. k is a photograph of the linear image of the measuring slit; Fig. 5 is a photograph of a diffraction image of a measuring slit;

reference half-plane and coherent components of the laser radiation beam, and implement projection and diffraction measurement methods in a single optical anomorphic system. An anamorphic optical system is obtained by positioning the second cylindrical lens in the front focal plane of a known projection lens (lens), behind which is also an additionally introduced beam-splitting cube for separating the radiation beam in two orthogonal directions. On the propagation path of the first beam beyond the first beam of the beam splitter cube there is an additionally introduced flat reflective mirror orthogonal to the axis of the incident beam of the beam to project it

CCD-receiver for photometry of the linear image of the measuring gap; Fig. 7 is a photograph of the video signal of a CCD receiver when photometting a diffraction image of a measuring slit; Fig. 8 is a functional block diagram of the connection of the CCD receiver with the CNC system of the machine; Fig. 9 is a functional block diagram of a video signal conditioning unit of the CCD receiver; Fig. 10 is a functional block diagram of connecting computer devices; Fig. 11 is a functional block diagram of connecting a CNC system to the drives of the machine; Fig. 12 is a flowchart of the algorithm for calculating the width of the measurement gap; Fig. 13 is a flowchart of a smoothing algorithm for a video signal of a CCD receiver; FIG. 1 is a block diagram of a video-differentiation algorithm;

-. The multiple rays course through the light- 5-body die on the known receiver; in fig. 15 block diagram of the algorithm. charge coupling. Moreover, the distance from the measuring gap along the light beam to the known projection lens is matched by the Gauss focusing condition with the distance from the latter through the light beam through the beam-splitting cube and the flat reflector to the known receiver with charge coupling. In addition, on the path of propagation of the second light beam behind the beam-splitting cube there is an additional

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ma search for extreme (max and min) video signal points; FIG. 16 is a block diagram of an algorithm for forming an array of coordinates of a video signal minima; in fig. 17 is a flowchart of calculating the average period T0.

A device for compensating machining errors on metal-cutting machines contains a coherent radiation source, successively located along the optical axis, a laser 1 mounted in the front plane of a spherical collimating

spheres formed chz concave branch

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CCD-receiver for photometry of the linear image of the measuring gap; Fig. 7 is a photograph of a video signal of a CCD receiver when photometting a diffraction image of a measuring slit; Fig. 8 is a functional block diagram of the connection of the CCD receiver with the CNC system of the machine; Fig. 9 is a functional block diagram of a video signal conditioning unit of the CCD receiver; Fig. 10 is a functional block diagram of connecting computer devices; Fig. 11 is a functional block diagram of connecting a CNC system to the drives of the machine; Fig. 12 is a flowchart for calculating the width of the measuring slit; Fig. 13 is a flowchart of a smoothing algorithm for a video signal of a CCD receiver; Fig. 1 is a block diagram of a video signal differentiation algorithm; in fig. 15 flowchart

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Nala; in fig. 15 flowchart

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ma search for extreme (max and min) video signal points; FIG. 16 is a block diagram of an algorithm for forming an array of coordinates of a video signal minima; in fig. 17 is a flowchart of an algorithm for calculating an average period T0.

A device for compensating machining errors on metal-cutting machines contains a coherent radiation source, successively located along the optical axis, a laser 1 mounted in the front plane of a spherical collimating

lens 2, behind which is located the first cylindrical lens 3. In the back focal plane of lens 3, there is a supporting half-plane 4, with which an optically transparent slit forms a controlled cutter (part) 5, the slit is oriented along the major axis of the ellipse of the focused beam and coincides with the front focal plane the second cylindrical lens 6, located in the front focal plane of the projecting lens (lens) 7; The lens 7 is designed to form a linear image of the measuring slot on a single face Inatom receiver 8 with charge coupling (CCD receiver), which is located behind lens 7 at a distance matched by the focusing condition of Gauss with its focal length and the distance from lens 7 to the measuring slit. To reduce the overall dimensions of the optical system, a beam-splitting cube 9 is positioned behind the projection lens, ensuring separation of the light flux falling on it in two mutually orthogonal directions. On the propagation path of the first light beam, a flat reflective mirror 10 is arranged to form, together with the lens 7, a linear image of the measurement slit on the photosensitive layer of the receiver 8 with charge coupling. At the same time, the distance from the lens 7 to the receiver 5 in the course of the light beam through the beam splitting cube 9 and the reflection from the mirror 10 satisfies the stipulated condition of Gauss focusing. A spherical concave reflecting mirror 12 is positioned along the path of the second light beam 11 through the counting cube 9 to project a diffraction image of the measuring slot onto the photosensitive layer of the charge-coupled receiver 8. At the same time, the distance from the back focal plane of the projecting lens 7 to mirror 12 is matched by the focusing condition of Gauss with its focal length and the distance from mirror 12 along the light beam through the beam-splitting cube 9 to the receiver 8 with charge coupling.

The output of receiver 8 with charge coupling is connected to block 13 of forming a video signal connected to

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turn with the computer processor 14. The video signal shaping unit 13 comprises a generator 15 of the clock frequency of the video signal sweep over time. The output of the clock generator 15 is connected to the input of the switch 16, which is designed to generate square start / reset pulses of the phase voltage generator 17, the input of which is connected to the output of the switch 16. The first, second and third outputs of the phase voltage generator 17 are respectively connected to the first , the second and third phase inputs of the receiver 8 with charge coupling. In addition, the first output of the phase voltage driver 17 is also connected to the input of the reference voltage driver 18, the four outputs of which are connected respectively to the four inputs (power, gate, substrate and housing inputs) of the receiver 8 with a charge connection, the signal output of which connected to the fifth output of the reference voltage driver 18 and the input of the operational amplifier (repeater) 19 to increase the power of the video signal. The output of the repeater 19 is connected to the first input of the filtrates block 20, the second input of which is connected to the first output of the former 17 phase voltages. The output of the filter block 20 is connected via a voltage amplifier 21 to a signal (analog) input of an analog-digital converter (ADC) 22, whose digital outputs are connected via an interface device 23 to a common bus 14. The trigger input of the ADC 22 is connected to an output register interface device 23. The initial signal of the common computer bus 14 is connected via a counting trigger 24 to the control input of the phase voltage generator 17, which is connected to the input Interrupt requirement of the interface device 23. A processor is connected to the common computer bus 14 25, random access memory 26, photo reader 27 via interface device 28, alphanumeric display 29 through interface device 30. In addition, the output of device 23 through phase voltage generator 31 and current amplifiers 32 is connected to step motor 33 of support 3.

The operation of the machining error compensation device on machine tools is as follows.

The output beam of laser 1 is collimated by lens 2 and propagates after it in the form of a parallel beam containing coherent radiation in the central region around the beam axis generated by the laser resonator and non-coherent spontaneous (luminescent) radiation in the peripheral region of the beam around the coherent component generated by the active laser element 1. Behind the lens 2 there is a first cylindrical lens 3, which is designed to focus the incident beam of radiation in only one direction. Therefore, in the back focal plane of the lens 3, the focused beam has the shape of an ellipse, the major axis of which coincides with the direction of beam focusing by the cylindrical lens 3. The beam focused by lens 3 illuminates the measuring slit formed by the additional support half-plane of the tool b, and the large axis of the ellipse of the illuminating beam coincides with the direction of the radial flow of the tool 5, and the reference half-plane is set statically in the region of the coherent component of the illuminating it ka radiation. Thus, the illumination of the measuring slit is achieved by a narrow, but long spot: tfii of the TOBO radiation beam. A projection lens 7, a beam-splitting cube 9 and a flat reflective mirror 10 form a linear image of the measuring slit on the CCD receiver 8. At the same time, a projecting lens 7, the beam-splitting cube 9 and a concave reflector 12 form a diffraction image of the measuring slit on the CCD receiver 8. When forming a blue line. The images of the measuring slit on the CCD receiver 8 illuminated the face of the statically installed support half-plane A and projected onto several first photocells of the sensitive layer of the receiver 8, and the top of the movable cutting tool 5 onto the rest of the sensitive layer. Further, when forming a diffraction image of a slit on the CCD receiver 8, the optical system is mounted.

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by the angular skew of the mirror 12 so that the sensitive layer of the CCD receiver 8 does not hit a zero diffraction maximum, i.e. it is shifted beyond the sensitive layer. Thus, two optical images of the measuring slit are projected onto the CCD receiver 8 at the same time by the anamorphic optical system — the linear image and the far region of the diffraction image, the photographs of which are shown in FIG. K and 5, respectively. To reduce the angular divergence of the light beam in these images, as well as to increase their brightness (illumination), a second cylindrical lens 6 is located between the measuring slit and the projecting lens 7, the lens 6 being located in the front focal plane of the lens 7, and the front focal plane of lens 6 combined with the plane of the measurement gap, i.e. the plane of the front (upper) face of the cutting tool. The diffraction image of the measuring slit is equidistantly spaced alternating maxima and minima of the light flux, which appear in the regular oscillation of the intensity of the light flux in the diffraction image. The oscillation period of the video signal is inversely proportional to the width of the measuring slit and can be recorded by the video signal of the CCD receiver (Fig. /) For slits no larger than 600-800 microns, illuminated only by the coherent component of the light flux incident on the slit. The soline image of the measuring slit is its shadow geometric projection, illuminated only within the slit width and visually observed as a bright light line, photometric by the CCD receiver 8, the video output of which (fig.b; repeats in amplitude the light flux in the salt image measuring gap.

The output video signal of the CCD receiver 8 is generated by block 13 and consists of periodically alternating, at regular time intervals, envelope pulses, which coincide in shape with the spatial intensity distribution: -; light po9

current in the image on the photosensitive layer of the CCD receiver 8. For generating the video signal in block 13, there is a clock frequency generator 15 that generates periodically repeated square voltage pulses at the output to the input of the switch 16. The switch 16 has six parallel outputs connected to the inputs of the phase voltage generator 17, for each of which the input pulses are sequentially distributed by the switch 16. The shaper 17 produces phase voltages in the form of rectangular pulses coming from its first, second, and third outputs to the corresponding three phase inputs of the receiver 8 with charge coupling. The duration of the pulses from each of the phase voltages is equal to the time interval between the leading edges of the two pulses that arrive from the corresponding output of the switch 16. Thus, a traveling in time wave of electric voltage along the photosensitive layer of the receiver 8 is formed, which carries the accumulated The charge is caused by the luminous flux incident on the receiver 8. Charger arrives at the output register of the receiver 8.

In order to increase the quantum efficiency of the electron output from the photosensitive layer of the receiver 8, appropriate electrical voltages are applied to its substrate and the gate of the output register, which are formed by the reference voltage generator 18. The output video signal of the receiver 8 is fed through the operational amplifier 19 (to increase the load capacity) to the input of the filter unit 20. Filter block 20 performs high-frequency filtering of a video signal from a pulsed form into a smoothed envelope, which repeats the shape of the intensity distribution of the light field on the photosensitive layer of receiver 8. Next, the output signal of filter block 20 is amplified by voltage amplifier 21 to increase the amplitude of the video signal, as well as bringing it into the input voltage range of the analog input of the ADC 22. The ADC 22 is started by the software processor 25 of the computer AND through the output

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interface register, art. j -; -. 2j- data exchange. From the digital output of the A / D converter 22, the ppdcg.digital code of the input zideosignnl enters the Pale interface registers. 23, from which it is read by the software processor 25 and the record. and the form of an array of numbers in operabti, bs. memory 26. Next, a digital oopaociKd video signal (i.e., a recorded array of numbers, the values of which are amplified by the amplitudes of the corresponding T-accounts of the video signal) is performed in g,; x / g mode in accordance with the algorithm used in FIG. 12. The essence of video signal processing according to this algorithm is related to the execution of a number of procedures, represented as separate algorithms at subsequent phpgs. At the first stage of processing the input video signal, it is smoothed to suppress random fluctuations caused by contamination of parts of the optical system, as well as trapped chips 13 / workpiece in the field of view of the optical system (see. FIG algorithm ca..

The video signal smoothing algorithm shown in Fig. 13 is that the video signal sample values corresponding to the A (I) elements of the masses A are intelligent:; ayut-: with the corresponding weighting coefficients H (1) and added together. The result of the summation is written into the cell A (I,), after which the index i is paid per unit and the process is repeated until the array A is reached. The result, smoothing 1, s - ::, corresponds to significant values; dnch array, the values of the smoothed video signal are recorded, t ... convolution of the original video signal. its img / best characteristic of the digital signal represented by the H ey array,.

Algorithm of differentiation, F1-, g. necessary to highlight the front and rear edges of the video signal corresponding to the projection image of the slit. It consists in calculating the difference between the T + 2- and 1-th elements of the array A using the video signal of the video signal, when the video signal is seen, it is recorded in the 1st -. | ..: ..-, and i-h,;.: .. to increases by C ;; i. chu. after the Yeh-oh prg.- process continues ds / ostizhesh; :: intsa. array.

The extremum search algorithm (maximum and minimum) of the video channel (Fig. 15) consists in sequentially checking all values of the differentiated array A for maximum and minimum. The initial values of the maximum and minimum are set equal to zero and are replaced with the newly determined maximums and minimums as they are detected. At the same time, such positions of maxima and minima are memorized, as a result of which, after viewing the array, the values and positions of the maximum absolute value of the maximum and minimum corresponding to the boundaries of the original solitary image of the slit are determined.

The slit width is calculated as the difference of these positions (Fig. 12), by a scaling factor equal to the ratio of the photocell size to the magnification of the optical system in the projection channel. If the resulting width is less than the maximum allowable software specified, then the slit width is recalculated from the diffraction image. It includes the smoothing of the newly introduced video signal, where the portion corresponding to the projection image is not processed, and the impulse response filters only the high frequency component of the signal. After that, the formation of an array of ordinates of minima is carried out (Fig. 16).

multiplied

The algorithm for forming the array of minima coordinates consists in successively checking the array of video signal values for the fulfillment of the minimum conditions; when a minimum is detected, its coordinate (i.e., the minimum element index) is written into an array of coordinate values M, after which the values of the distances between two adjacent minima are calculated which are equal to the difference of the values of two adjacent elements of the array M. Difference of K-th and K + 1 -th values of array M are written in the C-th elements of the array of periods T, which is intended to determine the average oscillation period of the video signal corresponding to the diffraction image of the slit. The algorithm for determining the average period is shown in FIG. 1 and consists in calculating the sum of all

the values of the array of T periods and its division by the number of elements.

Next, the measuring slit width is determined as the ratio of the product of the laser radiation wavelength and the equivalent distance 1 from the slit to the CCD receiver to the average period T0 of the amplitude amplitude of the video.

To determine the size of the wear of the cutter 5, it is moved by the caliper 3 to the initial zero position, i.e. form a measuring gap of width a, |, the value of which is measured and stored in a computer. The part is machined to the required size by specifying the path of the tool 5 relative to the part blank and returns the caliper 3 to the initial zero position. Measure the width a2 of the formed measuring slit, determine the size

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up to 50

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a, the tool 5 and the curvature h recite the path of its movement in the radial direction by the amount of wear h, which provides compensation for the dimensional wear h of the tool and the required diameter of the part.

To control directly the diameter of the workpiece, the optical system of the device, which contains parts 1-12 in one housing, is installed in the support of the machine 3 and is moved along the part.

The measuring target in this case is formed by the surface profile of the workpiece and the reference half-plane k. When moving the optical system of the device along the surface of the part, the deviations of the width and the slits are proportional to the linear deviations of the diameter of the part.

The motion path of the tool 5 relative to the part is formed by the processor 25 as a sequence of square pulses arriving over a common computer bus 14 through the interface device 23 to the inputs of the phase voltage generator 31. The number of pulses is directly proportional to the amount of movement of the caliper 3, and the pulse frequency is directly proportional to the speed of movement of the caliper 3. The direction of movement of the caliper 3 is determined by the number of the beginning (output) of the device 23, from which the pulses enter the input of the imager 31. The outputs of the imager 31 are connected through current amplifiers 32 to the inputs of the stepper motors 33, connected via mechanical engagement with the caliper 3.

Claims (1)

Claims: A device for compensating machining errors on metal-cutting machines, containing a photoelectric converter connected in series, including a radiation source and a projecting lens, in the focusing plane of which a photoreceiver is installed, including a single-axis receiver, connected through a video signal shaping unit to the analog-to-digital input converter, the output of which is connected via an interface device with a number system processor machine control, the lens is located between the measured part and the receiver with charge coupling, and the focal length of the lens is matched by the Gauss focusing condition with the distance from the lens to the part and the distance from the lens to the charge coupled receiver, characterized in that, in order to increase the accuracy of measurements and expand the functionality of the device, the optical system is anamorphic and is equipped with a coherent radiation source located in the anterior focus. I FIG. 2 five 0 five 0 five a spherical collimating lens, behind which a first cylindrical lens is installed, in the back focal plane of which an additional supporting half-plane is located to form an optically transparent slit with the surface of the sample under investigation, coinciding with the front focal plane of the second cylindrical lens installed in the front focal plane of the projecting lens , between the lens and the receiver, with a charge connection, a beam-splitting cube is installed, beyond the first edge of which A flat reflective mirror is located at the front of the radiation beam, and a spherical concave reflective mirror is located behind the second edge along the transmitted radiation beam, the focal length of which is matched by the Gauss focusing condition with the distance to the rear focal plane of the projection lens and the distance from the receiver to the distance from the projection lens in the course of the light beam through the first face of the beam-splitting cube and the flat reflective mirror to the receiver with charge the communication is equal to the distance from the lens along the light beam through the second face of the beam-splitting cube and the spherical mirror to the receiver with the charge coupling. Fig.8 3 2 start /four FIG. ten : about ll f gs I I Start S: F I: / S: 5 + H (I) A (J + I-J) I I + i Hem Hem EndL FIG. 13 Havauio Fit. 14 t / a z / iff  TO NA) 7 Aa FIG. sixteen Start   f I: / T0 T0 + T (I) t (/ gwagj FIG. 17