Digital measuring device for grinding area of aircraft steel brake disc

Abstract

The application discloses a kind of digital measurement device of aircraft steel brake moving disc repair polishing area, including image acquisition system and image processing system, image processing system includes the calibration submodule, moving disc polishing area identification submodule, moving disc polishing area calculation submodule and label image output submodule connected in sequence, and moving disc polishing area identification submodule, moving disc polishing area calculation submodule and label image output submodule are respectively connected with local database support submodule.The present application is based on the morphological characteristics of moving disc polishing area image, and the physical area of each polishing area and the relative proportion of polishing area and new brake disc friction piece area are calculated by image recognition algorithm, while meeting the requirements of manual, precise measurement can be realized, safety is improved, moving disc scrap rate is reduced, aviation material cost is saved, moving disc repair qualification rate and available efficiency are improved;Computer program is automatically compared and calculated, easy to use, improve work efficiency, reduce labor cost.

Description

TECHNICAL FIELD

[0001] The application relates to a digital measurement device for grinding area of a repaired aircraft steel brake moving disc. BACKGROUND

[0002] The aircraft steel brake assembly is mainly composed of a total bearing assembly, a torsion assembly and a hot component assembly. The hot component assembly is a main consumable part. After each brake grinding, the hot component assembly needs to be reconfigured, replaced and assembled. The hot component assembly is composed of a static disc and a moving disc. The static disc is riveted by a framework and a friction plate. The friction plate needs to be replaced with a new part after each brake grinding. The moving disc is replaced with a new part or a usable part according to the hot component configuration. The moving disc is divided into two groups. One group of the moving disc is composed of three thick discs, and the other group of the moving disc is composed of two thin discs. The thick disc is replaced with a new part, and the thin disc is replaced with a usable part from the thick disc after cleaning or grinding or a new part.

[0003] According to the manual requirements, the thick disc after grinding has minimum weight and minimum thickness requirements, and the grinding and flattening area needs to reach more than 60% to be used as a usable part of the thin disc. The weight and thickness parameters of the thick disc after grinding can be accurately measured by using a traditional measuring device. However, for the grinding and flattening area, since it is distributed in an irregular curved surface, there is no method to accurately measure it at present. It is classified as a visual inspection (or estimation) item, but this process is time-consuming and laborious, and the accuracy is poor, and the repair qualification rate cannot be scientifically controlled, so that there is a safety hazard. SUMMARY

[0004] The application aims to provide a digital measurement device for grinding area of a repaired aircraft steel brake moving disc, which is low in cost, can realize accurate measurement, is convenient to use, improves work efficiency and safety.

[0005] The application is realized by the following technical measures: a digital measurement device for grinding area of a repaired aircraft steel brake moving disc, characterized by comprising an image acquisition system for acquiring moving disc image data including a standard reference image and an image processing system for processing the moving disc image data, wherein the image processing system comprises:

[0006] A calibration sub-module is used to obtain the physical area of the standard reference;

[0007] A moving disc grinding area identification sub-module is used to perform gray scale conversion, image enhancement, background noise elimination and binary processing on the moving disc image data;

[0008] A moving disc grinding area calculation sub-module is used to determine the boundary of the grinding area and calculate the area of the grinding area;

[0009] A label image output sub-module is used to control the output of the calculation result.

[0010] The local database support submodule is used for storing parameters of the disc polishing area identification submodule, the disc polishing area calculation submodule and the label image output submodule;

[0011] The calibration submodule, the disc polishing area identification submodule, the disc polishing area calculation submodule and the label image output submodule are sequentially connected, and the local database support submodule is connected with the disc polishing area identification submodule, the disc polishing area calculation submodule and the label image output submodule respectively.

[0012] The present application is based on the disc polishing area image morphological features, and the physical area of each polishing area and the relative proportion of the polishing area and the new brake disc friction plate area are calculated through image recognition algorithm, so that the precision measurement can be realized while meeting the manual requirements, the safety can be improved, the disc scrapping rate can be reduced, the aviation material cost can be saved, the disc repair qualification rate and the available efficiency can be improved; the computer program is used for automatic comparison and calculation, so that the work efficiency is improved, and the labor cost is reduced.

[0013] The calibration submodule calculates the reference object area first, the reference object is the disc center hole, that is, the irregular area with disconnected boundary, the hole area formed after connecting the disconnected boundary is the reference object area, and the pixel number of the reference object is calculated, and then the physical area of the standard reference object is calculated according to the calculation result.

[0014] The disc polishing area identification submodule includes a gray scale conversion device for converting the disc image into a two-dimensional matrix image, a primary image enhancement control panel for enhancing the disc image, a background noise data elimination control panel for eliminating the background noise of the disc image, a secondary image enhancement control panel for enhancing the disc image, and a binary processing control panel for binaryzation of the disc image.

[0015] The disc polishing area identification submodule includes a disc flipping switch for switching the disc from one side to the other side to obtain the image of the side.

[0016] The disc polishing area calculation submodule includes a polishing area boundary tracker for tracking the outer boundary of the disc binary image, a polishing area boundary object collector including a boundary area pixel matrix and a boundary area label matrix, a standard reference object locator for separating the standard reference object from the polishing area boundary object collector, and a polishing area area calculation unit for calculating the polishing area.

[0017] The boundary region pixel matrix comprises boundary pixel coordinates and boundary perimeter constituted by all polishing region boundaries output by the polishing region boundary tracker, and constitutes a region pixel element package three tuple matrix; the boundary region label matrix comprises region area and region center coordinates constituted by all polishing region boundaries output by the polishing region boundary tracker, and constitutes a region label element package matrix.

[0018] The standard reference locator calculates the roundness Ri of each boundary region containing the boundary region of the standard reference, and compares it with the set roundness threshold rt to obtain a boundary region object of Ri >= rt, wherein the boundary region object with the maximum roundness is the standard reference object.

[0019] The calculation process of the polishing region area calculation unit comprises: extracting the area Pb within the boundary of the standard reference, accumulating and summing the region area A in the boundary region label matrix to obtain the polishing region area Pa, obtaining the polishing reference r=Pa / Pb; according to the input standard reference physical area s, output the total polishing region area A=sxr; according to the input of the new disc friction plate area B, output the total polishing region proportion β=A / B; according to the input of the small area threshold ts, conditionally count the region area A in the boundary region label matrix, that is, count and accumulate and sum the polishing region area <= ts, form statistical data, and input to the label image output submodule.

[0020] The label image output submodule outputs the outer boundary of the polishing region and the physical area label thereof, the standard reference and the physical area label thereof, the calculation result label of the polishing area calculation submodule, the artificial labeling label, the two-dimensional code label and the polishing region area histogram.

[0021] The grinding area outside boundary and its physical area label of the invention include significant area and small area, the small area is determined by the small area threshold ts in the grinding area area calculation unit, the grinding area smaller than the small area threshold ts is marked as a small area, otherwise it is marked as a significant area; The standard reference and its physical area label include the standard reference outside boundary, the standard reference area center and the physical area of the standard reference; The grinding area calculation sub-module result label consists of: disc surface identification, both sides of the moving disc need to be ground, total grinding area identification, total grinding area ratio, total grinding area number, small area grinding area number, small area grinding area threshold, whether the small area is marked, whether the small area area is included in the total grinding area, and new disc friction plate area; The grinding area histogram displays the numerical characteristics of each grinding area, including significant grinding area ratio, small area ratio, all grinding area average, small area average, all grinding area standard deviation, significant grinding area average, significant grinding area standard deviation, maximum grinding area and small area maximum.

[0022] The image processing system of the invention includes an area calculation and label image output parameter control panel, which includes:

[0023] Grinding area evaluation tab for controlling the input of grinding area calculation reference parameters and label image text annotation;

[0024] Numerical label output tab for controlling the generation and output of numerical labels on the label image;

[0025] Tool bar for generating color grinding area on the label image, displaying grinding area outside boundary on the label image, generating calculation result label on the label image and outputting complete label image, saving control panel parameters.

[0026] The local database support submodule of the invention stores the parameters of the area calculation and label image output parameter control panel, and corresponds each moving disc image with the workshop material receiving history and its work order to form integrity, the local database support submodule includes the following storage library tables: brake material receiving record table, brake disc repair work order table, moving disc grinding area identification parameter table, moving disc grinding area identification resource parameter table and moving disc grinding area calibration output parameter table.

[0027] The image acquisition system comprises an upper box body which is internally light-proof and a lower box body for temporarily storing a disk to be measured, an imaging device and a light source are arranged in the upper box body, the imaging device is connected with the image processing system, a pull-out type rotary fine adjustment mechanism for placing the disk to be measured and adjusting the relative position of the disk to the light source is arranged on a partition plate between the upper box body and the lower box body.

[0028] The pull-out type rotary fine adjustment mechanism comprises an upper support disc, a support block arranged on the upper support disc for supporting the disk, a lower support disc, a sliding mechanism arranged between the upper support disc and the lower support disc, a support ball ring arranged on the partition plate, a handle type driving gear and a driven gear, the lower support disc is supported on the balls of the ball ring, the lower support disc is rotatably installed on the partition plate through a rotating shaft, the driven gear is installed on the rotating shaft, the handle type driving gear is composed of a handle part and a sector gear, the sector gear is rotatably installed on the partition plate and is engaged with the driven gear.

[0029] A disk storage slot which can be pushed and pulled and is used for temporarily storing the disk to be measured is arranged in the lower box body, the disk storage slot is arranged in parallel and comprises a plurality of disk storage slots, and the disk storage slot is slidably installed on a split bearing type ball guide rail.

[0030] The lower box body is composed of a rectangular support frame and a skin arranged on the inner and outer sides of the support frame, a fine adjustment mechanism fixing frame is arranged on the top surface of the support frame, the partition plate is formed by the skin arranged above and below the fine adjustment mechanism fixing frame, and the rotating shaft of the lower support disc and the rotating shaft of the handle type driving gear are arranged on the fine adjustment mechanism fixing frame.

[0031] Compared with the prior art, the present application has the following remarkable effects:

[0032] (1) The present application is based on the image form feature of the polishing area of the disk, and the physical area and the proportion of each polishing area are obtained through image recognition algorithm, which fills the gap of the polishing area accurate measurement technology method in the maintenance manual.

[0033] (2) The present application can reduce / eliminate / effectively reduce the uncertainty of the workers in measurement estimation, improve the recognition accuracy, better meet the requirements of the manual, eliminate the safety hidden danger and improve the safety level.

[0034] (3) The present application adopts simple and fast digital photography, and the computer program automatically compares and calculates, which reduces the labor cost and improves the work efficiency.

[0035] (4) The present application reduces the disk scrap rate through accurate measurement, saves the cost of aviation materials, improves the qualified rate of disk repair and the available efficiency, and improves the economy.

[0036] ⑸The application automatically generates image hash two-dimensional code, which is saved integrally with the label image, is anti-tampered, and is electronically archived and measured.

[0037] ⑹The database module of the application provides the possibility of brake disc polishing quality regression analysis, and provides upstream and downstream data support for the workshop MES (production execution management system) system to build a brake disc repair quality tracking mechanism.

[0038] ⑺The maintenance unit can apply for brake disc subcomponent maintenance capability according to the device, provide services for other airlines, and improve the industrialization capability of the enterprise. BRIEF DESCRIPTION OF DRAWINGS

[0039] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0040] Figure 1 is a schematic diagram of the component structure of the application;

[0041] Figure 2 is a schematic diagram of the overall structure of the image acquisition system (without inserting the measured dynamic disc into the dynamic disc storage slot);

[0042] Figure 3 is a schematic diagram of the explosion structure of the image acquisition system;

[0043] Figure 4 is a schematic diagram of the three-dimensional structure of the pull-out rotary fine adjustment mechanism;

[0044] Figure 5 is a side view of the pull-out rotary fine adjustment mechanism;

[0045] Figure 6 is a schematic diagram of the explosion structure of the pull-out rotary fine adjustment mechanism;

[0046] Figure 7 is a schematic diagram of the structure of the fine adjustment mechanism fixed frame on the skin;

[0047] Figure 8 is a schematic diagram of the structure of the lower box support frame;

[0048] Figure 9 is an effect diagram of the imaging of the standard block and the measured dynamic disc;

[0049] Figure 10 is a schematic diagram of the component structure of the image processing system;

[0050] Figure 11 is one of the schematic diagrams for calculating the physical area of the circular standard reference;

[0051] Figure 12 is the second schematic diagram for calculating the physical area of the circular standard reference;

[0052] Figure 13 is a schematic diagram of the component structure of the moving disc polishing area identification sub-module;

[0053] Figure 14 is a schematic diagram of the component structure of the moving disc polishing area calculation sub-module;

[0054] Figure 15 is a schematic diagram of the component structure of the polishing area boundary object collector;

[0055] Figure 16 is a calculation flowchart of the standard reference object locator;

[0056] Figure 17 is a calculation flowchart of the polishing area area calculation unit;

[0057] Figure 18 is a schematic diagram of the polishing area evaluation tab;

[0058] Figure 19 is a schematic diagram of the numerical label output tab;

[0059] Figure 20 is a schematic diagram of the tool bar. DETAILED DESCRIPTION

[0060] The application will be further described through the description of the specific embodiments, but this is not a limitation of the application, and those skilled in the art can make various modifications or improvements according to the basic idea of the application, as long as they do not deviate from the basic idea of the application, and they are within the protection scope of the application.

[0061] As shown in Figure 1 , the application is a digital measurement device for the polishing area of a repaired aircraft steel brake moving disc, which comprises an image acquisition system 1 for acquiring moving disc image data including standard reference object images and an image processing system 2 for processing the moving disc image data, wherein the image acquisition system 1 comprises an upper box body 3 with internal light shielding and a lower box body 4 for temporarily storing the moving disc to be measured, an imaging device 5 and a light source 6 are arranged in the upper box body 3, the imaging device 5 is connected with the image processing system 2 through a USB data line or WIFI or Bluetooth, etc., a pull-out type rotary fine adjustment mechanism for placing the moving disc to be measured 8 and adjusting its relative position with the light source 6 is arranged on the partition plate 7 between the upper box body 3 and the lower box body 4.

[0062] According to the brake disc repair process flow, the brake disc polishing process and the polishing area measurement are two independent processing links, and the operations are not synchronized, and the lower box body provides an independent temporary storage area for the moving disc to be measured.

[0063] Due to the serious optical pollution of the workshop production environment (including natural light, work lighting, and various colored warning lights, etc.), the artificial shooting conditions are poor, the upper box body optically isolates the environmental light A, the inside of the box body is paved with matte materials, the internal point light source is converted into scattered parallel light, and the reflection and uneven illumination of the brake disc polishing flat surface are eliminated. The upper box body adopts a fixed height rigid support framework to eliminate the uneven size or shaking of the digital imaging size which is not conducive to data processing of the image processing system.

[0064] In order to reduce the weight of the upper box body and reduce the pressure on the lower box body, the side plate of the upper box body is made of acrylic plate, which is opaque and has a white matte surface. The top cover pull-out cover plate is designed with an acrylic material, and the top cover plate can be opened to form a storage box structure with the ceiling of the box body. A hole is provided in the center of the ceiling of the box body to provide a centering position for the imaging device. A white active matte light source (non-point light source, such as a light strip or a light bar, etc.) is installed on the ceiling of the box body. A high-density sponge is used to fix the camera (imaging device) and the installation hole to maintain optical sealing. In order to ensure uniform illumination inside the box body, the light strip (or other light source) is installed on the upper edge of the inside of the upper box body (the ceiling of the box body) in a down-hanging manner. At the same time, in order to prevent light leakage or introduction of environmental light pollution from the side edges of the double doors, rubber sealing strips are installed on the side edges and the lower edge of the double doors.

[0065] The pull-out type rotary fine adjustment mechanism includes an upper support disc 10, four arc-shaped support blocks 11 arranged on the upper support disc 10 for supporting the measured disc 8, a standard block 12 arranged on the upper support disc 10, a lower support disc 13, a sliding mechanism arranged between the upper support disc 10 and the lower support disc 13, a support ball ring 14 arranged on the partition plate 7, a crank handle type driving gear 15, and a driven gear 16. The lower support disc is supported on the balls 17 of the ball ring 14, and the lower support disc 13 is rotatably installed on the partition plate 7 through a rotating shaft, and the driven gear 16 is installed on the rotating shaft. The crank handle type driving gear 15 is composed of a handle part and a sector gear 20, and the sector gear 20 is rotatably installed on the partition plate 7 and engaged with the driven gear 15.

[0066] The measured brake disc is horizontally placed on the four support blocks of the fine adjustment mechanism; the fine adjustment mechanism provides support and fine adjustment functions for the measured brake disc inside the upper box body. The worker adjusts by rotating the handle, and the adjustment accuracy is determined by the number of teeth of the sector gear; the adjustment range is determined by the angle of the sector gear and the stroke of the handle. By changing the relative position of the brake disc (friction plate) and the light source, the uneven illumination caused by accidental factors is eliminated.

[0067] The upper support disc 10 is made of stainless steel, and bears the gravity of the brake disc to be tested. Four aluminum (alloy) support blocks are fixedly installed on the upper surface of the upper support disc to provide horizontal support for the brake disc to be tested. The surface of the support blocks is polished to prevent scratching the friction plate of the brake disc to be tested.

[0068] The upper surface of the upper support disc is imaged together with the brake disc to be tested, and becomes part of the image background. Therefore, the upper surface of the upper support disc is black and matte to reduce the color difference between the unpolished area and the background in the identified image, and highlight the polished area as the main object.

[0069] The lower support disc is made of stainless steel, and the sliding mechanism is composed of guide rails 18 and sliding blocks 19. The sliding blocks can slide along the guide rails. In this embodiment, three guide rails 18 and sliding blocks 19 are fixedly installed on the upper surface of the lower support disc. The sliding blocks 19 are fixedly connected with the upper support disc 10, and the guide rails 18 are fixedly connected with the lower support disc 13.

[0070] Both the guide rails and the sliding blocks are made of stainless steel. Small stainless steel double-row ball low-speed guide rails are fixedly installed on the upper surface of the lower support disc to bear the pulling motion of the brake disc to be tested, and have large load and are easy to maintain. A ball retaining plate is used to keep the relative motion of the balls in the ball grooves on the sliding blocks. The ball retaining plate is detachable to release the balls for lubrication and maintenance. Stop blocks are installed at both ends of the guide rails (fixedly installed on the surface of the lower support disc) to prevent the brake disc to be tested from being pulled out too much. Three universal ball bearings are provided in front of the distal end stop block of each guide rail, which are fixedly installed on the upper surface of the lower support disc to provide horizontal support when the brake disc to be tested is pulled out to prevent the guide rail from being vertically deformed. An end cover plate and a sealing gasket are installed at the end of each sliding block to protect the brake disc to be tested from being damaged by impact with the stop block when it is pulled out / pushed in.

[0071] The rotating shaft of the lower support disc is composed of a thrust bearing, a driving support shaft, and a roller bearing. The upper bearing surface of the thrust bearing is attached to the center area of the lower surface of the lower support disc without fixed connection, only providing vertical support force. The outer thread on the top end of the driving support shaft is connected with the inner thread in the center hole of the lower support disc, and then locked by a washer. The screw end of the driving support shaft is interference-fitted with the driven gear, the torque is transmitted to the lower support disc by the passive gear driven by the crank handle type driving gear, to drive the rotation adjustment of the lower support disc. The screw of the driving support shaft is interference-fitted with the roller bearing, which is inserted (interference) into the center hole of the fine adjustment mechanism fixed frame 20 to provide rolling support in the radial direction for the fine adjustment of the crank handle type driving gear. The fine adjustment mechanism fixed frame 20 is fixedly connected with the skin 21 on the top surface of the lower box body, as shown in Figure 7 , which will be described in detail later.

[0072] The support ball ring is composed of a ring body and stainless steel balls, the stainless steel balls are inlaid in the ring body, and the stainless steel balls are uniformly distributed according to the circumference of the ring body, and support the low-speed rotating movement of the lower support disc.

[0073] The handle type driving gear 15 is made of stainless steel. The rotating shaft of the handle type driving gear 15 is the driving gear shaft 22, which is fastened and connected with the fine adjustment mechanism fixed frame 20 to serve as a driving support point. The handle type driving gear 15 is meshed and connected with the passive gear 16, and the passive gear 16 is interference-fitted with the lower end of the driving support shaft. The handle part of the handle type driving gear 15 is manually actuated to drive the lower support disc to rotate, so as to fine adjust the angle of the measured brake disc. The driving gear shaft is interference-fitted with the roller bearing, the roller bearing is inlaid (interference) and installed in the positioning hole, and the top end of the driving support shaft is fastened and connected with the fine adjustment mechanism fixed frame 20 to provide stable rotating support for the handle part.

[0074] The standard block is placed on the upper surface of the upper support disc and in the center hole of the measured disc, and the imaging device acquires the standard block image through the center hole of the measured brake disc to become part of the measured brake disc image. The standard block image provides a relative physical size reference for the measured brake disc image. The standard block is made of stainless steel or aluminum alloy or other equivalent wear-resistant and corrosion-resistant materials, and is treated with white matte on both sides. The shape is circular, the diameter is less than the diameter of the center hole of the measured brake disc, and the thickness is equal to the sum of the thickness of the brake disc and the thickness of the support block, so as to avoid lateral shadow of the standard block.

[0075] In order to reduce the total weight of the box body and the circumferential torsional force, the lower box body adopts a frame type support skin structure, the lower box body 4 is composed of a rectangular detachable support frame 23 and a skin arranged on the inner and outer sides of the support frame 23, the skin is made of stainless steel material, does not bear the main load, and is fastened and connected with the support frame to provide a relatively isolated storage space for the inside of the box body. The top surface of the support frame 23 is provided with a fine adjustment mechanism fixed frame 20, and the upper and lower parts of the fine adjustment mechanism fixed frame 20 are respectively provided with a skin 21 to form a partition plate, and the rotating shaft of the lower support disc 13 and the rotating shaft of the handle type driving gear are arranged on the fine adjustment mechanism fixed frame 20. The fine adjustment mechanism fixed frame 20 is a cross-shaped frame body, the middle part has a thrust bearing groove 25 and a shaft hole 26 for assembling a thrust bearing and a driving support shaft, the center of the upper outer skin is provided with an opening, and the center of the upper inner skin is provided with an opening, which provides an upward channel for the thrust bearing of the fine adjustment mechanism and a centering for the fine adjustment mechanism.

[0076] The main function of the lower box 4 is to provide a temporary storage area for the brake disc detection process and a support platform for the upper box. The box adopts a frame support skin structure, and the bottom adopts a metal split bearing type ball guide as the bottom plate to carry the storage groove and the brake disc, so as to ensure the support strength while minimizing the total weight. The front side of the box is open and faces the worker (no door), and the other five box panels (including the bottom plate) are made of stainless steel. The bottom plate is fastened and connected to four height-adjustable support feet at the four corners to adapt to the unevenness of the workshop floor and keep the shooting platform level.

[0077] The lower box 4 is provided with a pull-out disc storage slot 9 for temporarily storing the disc to be tested. The disc storage slot 9 is parallelly arranged and can be pulled out individually. The disc storage slot 9 is slidably installed on the split bearing type ball guide 24, as shown in Figure 3 .

[0078] The imaging device 5 uses a card-type digital camera or a digital imaging device such as a smart phone. In order to meet the output accuracy required by the device, the digital imaging must at least meet the following conditions: horizontal resolution (dpi) = vertical resolution (dpi) ≥ 72; pixel size (height x width) ≥ 4096 x 3072; pixel ratio (height: width) ≥ 4:3; and support RGB color imaging. The light source 6 uses a white parallel light source (light strip) built-in the upper box, and the digital imaging device flash (if any) is turned off. The standard block 12 placed in the upper box is used as a standard reference, which is placed in the center hole of the disc to be tested and integrated with the entire disc imaging. The effect is shown in Figure 9 .

[0079] The image processing system 2 is installed in a graphics workstation 27, which serves as the material basis for the computing power and storage of the image processing system. The basic principle of the image processing system 2 is as follows:

[0080] (1) Set the standard reference, and obtain its physical area s through the calibration submodule;

[0081] (2) Through the image recognition algorithm, obtain the ratio of the number of polished area image dots (P a ) and the number of standard reference dots (P b ), that is, the grinding reference

[0082] (3) Get the polished area A = s·r

[0083] (4) Get the polished area A and the ratio of the new disc friction area B

[0084] Thus, the requirements of the brake disc repair processing maintenance manual for the polishing area parameter are met.

[0085] As Figures 10 to 20 , the image processing system 2 comprises a calibration sub-module, a dynamic disc polishing area identification sub-module, a dynamic disc polishing area calculation sub-module, a label image output sub-module and a local database support sub-module, wherein:

[0086] The calibration sub-module is used for obtaining the physical area of a standard reference object;

[0087] Principle: Since the pixel density of digital photos of different resolutions is different, the device needs to be calibrated before use. The purpose of calibration is to obtain the physical area of a standard reference object, which serves as a reference basis for polishing area calculation.

[0088] First, calculate the reference reference object area: the reference reference object area is obtained by engineering mapping or physical measurement. In the device, the reference reference object is the center hole of the dynamic disc (on the physical brake disc, this "hole" is not a geometric circle, but an irregular area with disconnected boundaries, and the disconnected boundaries are connected to form a "hole" area), and its diameter / area is determined by engineering mapping. The number of pixels of the reference reference object is obtained by measuring the "geometric object measurement toolbox" of the image processing system, and the toolbox provides two functions of circular and polygon geometric area measurement. According to the reference reference object area, the physical area of the circular standard reference object is calculated, which is as follows:

[0089] Input the reference reference object area in the area inch (Area inch) unit, keep the area pixel (Area pix) unit and the pixel density (ppi 2 ) unit two parameters as 0, and select the "circle" function button; click the diameter of the center hole of the brake disc (reference reference object), and the "geometric parameter output" panel outputs the radius (ppi) value and the area (ppi 2 ) value in pixels; at the same time, the center point of the measured geometric object gives the area (ppi 2 ) value mark, and the center point to the radius edge horizontal counterclockwise 45° direction gives the radius mark (ppi), as shown in Figure 11 .

[0090] Copy the "area (ppi 2 )" value output by the "geometric parameter output" panel to the area and select the "circle" function button, click the diameter of the "standard reference object", and the "geometric parameter output" panel outputs the radius (inch) value and the area (inch 2 ) value in inches; at the same time, the center point of the measured geometric object gives the area (inch 2 ) value mark, and the center point to the radius edge horizontal counterclockwise 45° direction gives the radius mark (inch). As shown in Figure 12As shown: in the pixel (Area pix) unit; select the "calculate fx" button, the pixel density (ppi 2 ) unit gives the pixel density value; calibration is complete.

[0091] As Figure 13 shown, the dynamic disc polishing area identification sub-module is used for gray scale conversion, image enhancement, background noise elimination and binary processing of the dynamic disc image data.

[0092] The dynamic disc polishing area identification sub-module comprises a gray scale graph converter used for converting the dynamic disc image into a two-dimensional matrix image, a primary image enhancement control panel used for enhancing the dynamic disc image, a background noise data elimination control panel used for eliminating the background noise of the dynamic disc image, a secondary image enhancement control panel used for enhancing the dynamic disc image and a binary processing control panel used for binary processing of the dynamic disc image.

[0093] The dynamic disc polishing area identification sub-module comprises a disc turning switch. Since the polishing flat surfaces of the dynamic disc to be measured are distributed on two sides of the dynamic disc, the disc turning switch can switch the identification object of the dynamic disc polishing area identification panel to the other side (A, B side identification has no sequence) of the dynamic disc, and the data reference relationship is completed by the local database support module. After the worker completes the image acquisition of the A side, the disc turning switch is clicked to execute the image acquisition of the B side.

[0094] The gray scale graph converter converts the input brake disc RGB color image into a two-dimensional matrix image (i.e. a gray scale graph), and retains the "contrast" and "brightness information" of the RGB color image. The primary image enhancement control panel provides dynamic disc image enhancement operation for the gray scale graph. The background noise data elimination control panel provides a calculation unit based on image morphological element operation, i.e. performing "first corrosion" and then "later expansion" data processing on the dynamic disc polishing image after the primary image enhancement, and eliminating the background noise data (bright spots). The secondary image enhancement control panel provides dynamic disc image enhancement operation after the background noise data elimination. The operation mode of the secondary image enhancement control panel is the same as that of the primary image enhancement control panel, and only the default value setting of the brightness adjustment is different. The binary processing control panel binary processes the image output by the secondary image enhancement control panel through threshold processing.

[0095] As Figure 14 shown, the dynamic disc polishing area calculation sub-module is used for determining the boundary of the dynamic disc polishing area and calculating the polishing area.

[0096] The moving disc polishing area calculation sub-module comprises, in sequence, a polishing area boundary tracker for tracking the outer boundaries of the moving disc binary image, a polishing area boundary object collector comprising a boundary area pixel matrix and a boundary area label matrix, a standard reference object locator for separating the standard reference object from the polishing area boundary object collector, and a polishing area area calculation unit for calculating the polishing area.

[0097] The polishing area boundary tracker: input the moving disc binary image (including the standard reference object), track the outer boundaries of the objects and the hole boundaries inside the objects. Considering the complexity and practicability of the calculation, the RBPS only tracks the outer boundaries of the objects (including the standard reference object), and the holes may be caused by polishing quality or uneven image illumination. Under the condition that the light source condition of the image acquisition module cannot be significantly improved, the holes can be eliminated by further adjusting the parameters of the moving disc polishing area identification sub-module.

[0098] As shown in Figure 15 , the polishing area boundary object collector comprises a boundary area pixel matrix and a boundary area label matrix, wherein the boundary area pixel matrix comprises boundary pixel coordinates (x, y) and boundary perimeter (S) formed by all the polishing area boundaries output by the boundary tracker, and forms a region pixel element package [{x}, {y}, {S}] three-tuple matrix. The boundary area label matrix comprises region area A and region center coordinates (also referred to as centroid coordinates Centroid) formed by all the polishing area boundaries output by the boundary tracker, and forms a region label element package [{A}, {Centroid}] matrix. Wherein, the centroid coordinates Centroid are used for label positioning in the label image output sub-module.

[0099] The standard reference object, as a part of the moving disc image, exists together with each polishing area in the polishing area boundary object collector. The function of the standard reference object locator is to separate the standard reference object from the polishing area boundary object collector.

[0100] As shown in Figure 16 , the standard reference object locator calculates the circularity of each boundary region (including the boundary region of the standard reference object) and compares it with a given circularity threshold (rt) to find the boundary region object with Ri >= rt, wherein the boundary region object with the largest circularity is the standard reference object, and the standard reference object provides a calculation reference for the polishing area area calculation unit. The circularity threshold (rt) is a decimal number between 0 and 1, generally between 0.6 and 0.9. If rt is too large, the standard reference object positioning will fail, i.e. the system considers that the standard reference object does not exist, so it cannot provide a calculation reference for the polishing area area calculation unit.

[0101] As shown in Figure 17As shown, the polishing area calculation unit needs three input parameters: SRP physical area s, new disc friction plate area B, and small area threshold ts. Among them, the SRP physical area s parameter is taken from the calibration submodule for the labeling of circular geometric objects; the new disc friction plate area B is taken from the brake thick dynamic disc engineering mapping diagram; the small area threshold ts is determined by the user according to the actual situation (generally, it is considered that the polishing area less than 0.1 inch is invalid polishing area). The operation process of the calculation unit is as follows:

[0102] ①Extract the area Pb (unit: pix 2 ) within the SRP boundary in the boundary region label matrix in the region object collector;

[0103] ②Sum the area A in the boundary region label matrix in the region object collector (excluding SRP area) to get the (total) polishing area Pa (unit: pix 2 );

[0104] ③Get the grinding reference r = Pa / Pb;

[0105] ④According to the input SRP physical area s, output the total polishing area A = s x r (unit: inch 2 );

[0106] ⑤According to the input new disc friction plate area B, output the total polishing area ratio β = A / B;

[0107] Among them, the small area polishing region statistical subunit performs conditional statistics on the area A in the boundary region label matrix according to the input small area threshold ts:

[0108] 1. Count the polishing area with area <= ts;

[0109] 2. Accumulate and sum the polishing area with area <= ts.

[0110] Form statistical data and input to the label image output submodule.

[0111] The label image output submodule is used to control the output of the calculation result, that is, to control the label output on the dynamic disc image, including the following types of labels:

[0112] 1. Polishing area outer boundary and its physical area label: the polishing area is composed of two parts: significant area and small area. Among them: the small area is determined by the small area threshold ts specified in the polishing area calculation unit, and the polishing area less than ts is labeled as a small area, otherwise it is labeled as a significant area. The two are distinguished by color, and the color can be specified by the user.

[0113] 2. Standard reference point (SRP) and its physical area label: including SRP outer boundary, SRP centroid and SRP physical area. SRP physical area parameter is taken from the annotation of circular geometric object in calibration sub-module; its annotation color can be specified by user.

[0114] 3. Polishing area calculation sub-module calculation result label: this label consists of the following contents: disc surface identification both sides of brake disc need to be polished, the system uses Side-[A] to identify one side and Side-[B] to identify the other side; total polishing area identification; total polishing area proportion (i.e. the proportion relative to the area of new disc friction plate); total polishing area number; small area polishing area number; small area polishing area threshold; whether small area is annotated; whether small area (polishing) area is aggregated in total polishing area; new disc friction plate area.

[0115] 4. Manual annotation label: input by user manually when the image processing system outputs the image, generally including brake disc weight and thickness parameters, and output as part of the image as a whole.

[0116] 5. Two-dimensional code label: the image processing system has a built-in hash code generator, which maps the original brake disc RGB color image into a unique MD5 code (hash value), and then converts the MD5 code into a barcode, which is output as part of the image as a whole, to ensure the non-tamperability of the original brake disc image, and to facilitate electronic archiving of the printed output label image.

[0117] 6. Polishing area area histogram: it is not directly output on the label image, but is output separately as another vector image. The histogram shows the numerical characteristics of each polishing area, which is beneficial for workshop personnel to deeply understand the polishing quality and improve the maintenance quality. The numerical characteristics of each polishing area include significant polishing area proportion, small area region proportion, average value of all polishing area, average value of small area region, standard deviation of all polishing area, average value of significant polishing area, standard deviation of significant polishing area, maximum polishing area and maximum value of small area region. The histogram also has the function of polishing area searching, which can find out the distribution of different area polishing areas on the friction plate, which is beneficial for workshop personnel to deeply understand the polishing quality and improve the maintenance quality.

[0118] The image processing system includes an area calculation and label image output parameter control panel, which is used to determine the input and detailed control of relevant parameters in the moving disc polishing area calculation sub-module and the label image output sub-module. The area calculation and label image output parameter panel includes a polishing area evaluation tab, a numerical label output tab and a tool bar.

[0119] Referring to Figure 18The polishing area evaluation tab is used to control the calculation of the polishing area and the text labeling of the label image. The calculation of the polishing area includes: standard reference area: this parameter determines the derivation of the physical area of each polishing area; new disc (moving disc) friction plate area: this parameter determines the derivation of the total polishing area and the total friction plate area ratio; roundness threshold: this parameter determines the positioning of the standard reference. The text labeling of the label image includes: label image title: usually the brake disc part number of the current image or other complex labeling information; label image horizontal coordinate label: usually auxiliary labeling information; label image vertical coordinate label: usually auxiliary labeling information; label image manual labeling content.

[0120] Referring to Figure 19 The numerical label output tab is used to control the generation and output of numerical labels on the label image. This includes: small area threshold: controls the generation of small area region label labeling; whether to output the polishing area statistical chart: controls whether to output the polishing area statistical chart; whether to generate a two-dimensional code: controls whether to output a two-dimensional code.

[0121] Referring to Figure 20 The tool bar is used to generate colored polishing areas on the label image, display the polishing area outer boundary on the label image, generate calculation result labels on the label image, and output the complete label image and save the control panel parameters.

[0122] Among them, the colored polishing area is generated on the label image: according to the continuity of the polishing area outer boundary, each polishing area is displayed in groups. Different colors represent discontinuous polishing areas (internal small holes are calculated according to the area they are in; standard reference is calculated as an independent area). In a single friction plate, the larger the single continuous polishing area, the better. Grouped display of colored polishing areas is beneficial to quickly and intuitively analyze the polishing quality of brake pads.

[0123] The polishing area outer boundary is displayed on the label image: in a single friction plate, the larger the single continuous polishing area, the better, and the polishing area (continuous area) outer boundary display is beneficial to quickly and intuitively analyze the polishing quality of brake pads.

[0124] The local database support submodule is used for storing the disc polishing area identification submodule, the disc polishing area calculation submodule, the label image output submodule, and the parameters of the area calculation and label image output parameter control panel, and simultaneously forming integrity correspondence between each disc image and the workshop material receiving history and its work order, and outputting the following beneficial effects: 1. Supporting image secondary opening and disc turning operation, secondary processing and optimization based on historical data, accumulation of a large amount of historical data, and providing the possibility of machine learning to automatically optimize the polishing area identification parameters; 2. Historical data retrieval, providing the possibility of brake disc polishing quality regression analysis; 3. Providing upstream and downstream data support for the workshop MES (Manufacturing Execution System) system to build a brake disc repair quality tracking mechanism.

[0125] The local database support submodule includes the following storage library tables: a brake material receiving record table, a brake disc repair work order table, a disc polishing area identification parameter table, a disc polishing area identification resource parameter table, and a disc polishing area calibration output parameter table. Among them, the brake material receiving record table is used for storing brake material receiving records, and data is obtained by creating a new material receiving record form; the brake disc repair work order table stores brake disc repair work orders (uniquely corresponding to the material receiving record), and data is obtained by creating / binding the work order; the disc polishing area identification parameter table stores disc polishing area identification parameters (uniquely corresponding to the material receiving record), and data is obtained by pressing the save button on the polishing area identification panel; the disc polishing area identification resource parameter table stores disc polishing area identification resource parameters (uniquely corresponding to the material receiving record), and data is obtained by pressing the save button on the polishing area identification panel; the disc polishing area calibration output parameter table stores disc polishing area calibration output parameters (uniquely corresponding to the material receiving record), and data is obtained by pressing the save button on the area calculation and label image output parameter control panel toolbar.

[0126] The data shows that after the repair, the thick disc availability rate that meets the manual repair standard is greater than 2 / 3; according to the relevant airworthiness management regulations, the sub-item of visual inspection cannot change the parent item configuration. That is, even if the thick disc of the visual inspection polishing area meets the manual standard, it can only be installed back to the original thin disc position of the brake removed. This means that the repair of a brake may cause a usable / qualified thick disc to be scrapped. Taking an airline with 200 aircraft as an example, the waste caused by this is about 5 million yuan per year. The device improves the brake disc polishing area from visual inspection to accurate calculation, which means that the additional qualified repair parts can be used as spare parts for other aircraft or other brakes, and the economic type is improved by at least 30%.

Claims

1. A digital measuring device for the overhaul and grinding area of ​​an aircraft steel brake disc, characterized in that: The system includes an image acquisition system for acquiring moving disk image data, including images of a standard reference object, and an image processing system for processing the moving disk image data. The image processing system includes: The calibration submodule is used to obtain the physical area of ​​a standard reference object; The moving plate grinding area recognition submodule is used to perform grayscale conversion, image enhancement, background noise removal, and binarization processing on the moving plate image data. The moving disc grinding area calculation submodule is used to determine the boundary of the moving disc grinding area and calculate the grinding area. The label image output submodule is used to control the output of calculation results; The local database support submodule is used to store parameters for the moving disc grinding area recognition submodule, the moving disc grinding area calculation submodule, and the label image output submodule; The calibration submodule, the moving disc grinding area recognition submodule, the moving disc grinding area calculation submodule, and the label image output submodule are connected in sequence, and the local database support submodule is connected to the moving disc grinding area recognition submodule, the moving disc grinding area calculation submodule, and the label image output submodule respectively. The image acquisition system includes an upper box that is internally light-proof and a lower box for temporarily storing the moving disk to be tested. The upper box contains an imaging device and a light source. The imaging device is connected to the image processing system. The partition between the upper and lower boxes is provided with a pull-out rotary fine-tuning mechanism for placing the moving disk to be tested and adjusting its relative position with the light source. The pull-out rotary fine-tuning mechanism includes an upper support plate, a support block on the upper support plate for supporting the moving plate, a lower support plate, a sliding mechanism between the upper and lower support plates, a support ball ring on the partition plate, a crank-type drive gear, and a driven gear. The lower support plate is supported on the balls of the ball ring. The lower support plate is rotatably mounted on the partition plate via a rotating shaft. The driven gear is mounted on the rotating shaft. The crank-type drive gear consists of a shank and a sector gear. The sector gear is rotatably mounted on the partition plate and meshes with the driven gear.

2. The digital measurement device for the overhaul and grinding area of ​​aircraft steel brake discs according to claim 1, characterized in that: The calibration submodule first calculates the area of ​​the reference object, which is the center hole of the moving disk, i.e., an irregular area with broken boundaries. The hole-shaped area formed by connecting the broken boundaries is calculated, and the area of ​​the hole-shaped area is the area of ​​the reference object. At the same time, the number of pixels of the reference object is calculated, and then the physical area of ​​the standard reference object is calculated based on the calculation results.

3. The digital measurement device for the overhaul and grinding area of ​​aircraft steel brake discs according to claim 2, characterized in that: The moving disc grinding area recognition submodule includes, in sequence, a grayscale converter for converting the moving disc image into a two-dimensional matrix image, a primary image enhancement control panel for enhancing the moving disc image, a background noise data elimination control panel for eliminating background noise in the moving disc image, a secondary image enhancement control panel for enhancing the moving disc image, and a binarization processing control panel for binarizing the moving disc image; the moving disc grinding area recognition submodule also includes a flip switch for switching the moving disc from one side to the other to acquire an image of that side.

4. The digital measurement device for the overhaul and grinding area of ​​aircraft steel brake discs according to claim 3, characterized in that: The moving disk grinding area calculation submodule includes, in sequence, a grinding region boundary tracker for tracking the outer boundary of the moving disk binary image, a grinding region boundary object aggregator including a boundary region pixel matrix and a boundary region label matrix, a standard reference object locator for separating the standard reference object from the grinding region boundary object aggregator, and a grinding region area calculation unit for calculating the grinding region area. The boundary region pixel matrix includes the boundary pixel coordinates and boundary perimeter of all grinding region boundaries output by the grinding region boundary tracker, forming a region pixel element triplet matrix. The boundary region label matrix includes the region area and region center coordinates of all grinding region boundaries output by the grinding region boundary tracker, forming a region label element matrix. The standard reference object locator calculates the roundness Ri of each boundary region, including the standard reference object boundary region, and compares it with a set roundness threshold rt to obtain boundary region objects with Ri ≥ rt, where the boundary region object with the largest roundness is the standard reference object. The calculation process of the grinding area calculation unit includes: extracting the area Pb within the boundary of the standard reference object; summing the area A in the boundary area label matrix to obtain the grinding area Pa; and obtaining the grinding reference ratio r = Pa / Pb; outputting the total grinding area A = s × r based on the input physical area s of the standard reference object; outputting the total grinding area ratio β = A / B based on the input friction pad area B of the new disc; and performing conditional statistics on the area A in the boundary area label matrix based on the input small area threshold ts, i.e., counting the grinding areas with a grinding area <= ts and summing the grinding areas with a grinding area <= ts to form statistical data, which is then input into the label image output submodule.

5. The digital measurement device for the overhaul and grinding area of ​​aircraft steel brake discs according to claim 4, characterized in that: The label image output submodule outputs labels for the outer boundary and physical area of ​​the polishing area, labels for the standard reference object and its physical area, labels for the calculation results of the polishing area calculation submodule, manually labeled labels, QR code labels, and a histogram of the polishing area area. The polishing area, as defined by the outer boundary and physical area label, includes a significant area and a small area. The small area is determined by a small area threshold ts specified in the polishing area calculation unit; polishing areas smaller than the small area threshold ts are labeled as small areas, otherwise they are labeled as significant areas. The standard reference object and its physical area label include the outer boundary of the standard reference object, the center of the standard reference object area, and the physical area of ​​the standard reference object. The polishing area calculation submodule... The module calculation result labels consist of the following: disc surface indication that both sides of the moving disc need to be polished, total polishing area indication, total polishing area percentage, total number of polishing areas, number of small polishing areas, small polishing area threshold, whether small areas are marked, whether the area of ​​small areas is included in the total polishing area, and the area of ​​the new disc friction pad; the polishing area histogram displays the numerical characteristics of each polishing area, including the percentage of significant polishing areas, the percentage of small areas, the average area of ​​all polishing areas, the average area of ​​small areas, the standard deviation of all polishing area areas, the average area of ​​significant polishing areas, the standard deviation of significant polishing area areas, the maximum area of ​​the polishing area, and the maximum area of ​​the small areas.

6. The digital measurement device for the overhaul and grinding area of ​​aircraft steel brake discs according to claim 5, characterized in that: The image processing system includes an area calculation and label image output parameter control panel, which includes: The Grinding Area Evaluation tab is used to control the input of calculation baseline parameters for the grinding area and the annotation of label images and text. The Numerical Label Output tab controls the generation and output of numerical labels on the label image; The toolbar is used to generate and display colored polished areas on the label image. The outer boundary is defined, the calculated labels are generated on the label image and the complete label image is output, and the control panel parameters are saved. The local database support submodule stores the parameters of the control panel for area calculation and label image output parameters, and establishes a complete correspondence between each moving disc image and the workshop receiving history and its work order. The local database support submodule includes the following storage tables: brake receiving record table, brake disc overhaul work order table, moving disc grinding area identification parameter table, moving disc grinding area identification resource parameter table, and moving disc grinding area calibration output parameter table.

7. The digital measurement device for the overhaul and grinding area of ​​aircraft steel brake discs according to claim 6, characterized in that: The lower housing is provided with a push-pull movable disk storage slot for temporarily storing the movable disk to be tested. There are several movable disk storage slots arranged in parallel. The movable disk storage slots can be slidably installed on the split-type bearing ball guide rail.

8. The digital measurement device for the overhaul and grinding area of ​​aircraft steel brake discs according to claim 7, characterized in that: The lower housing consists of a rectangular support frame and skins arranged on the inner and outer sides of the support frame. A fine-tuning mechanism fixing frame is provided on the top surface of the support frame. Skins are provided above and below the fine-tuning mechanism fixing frame to form the partition. The rotation shaft of the lower support plate and the rotation shaft of the crank-type drive gear are both arranged on the fine-tuning mechanism fixing frame.

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