CN112797909B

CN112797909B - Method for measuring height difference and outer aperture difference of domestic ceramic edge

Info

Publication number: CN112797909B
Application number: CN202110232321.4A
Authority: CN
Inventors: 曹利钢; 王小平; 冯浩; 王俊祥; 沈家祥; 陈文鑫
Original assignee: Jingdezhen Ceramic Institute
Current assignee: Jingdezhen Ceramic Institute
Priority date: 2021-03-03
Filing date: 2021-03-03
Publication date: 2022-06-03
Anticipated expiration: 2041-03-03
Also published as: CN112797909A

Abstract

The utility model discloses a method for measuring the height difference and the outer aperture difference of a domestic ceramic mouth edge, which comprises the following steps: firstly, placing the domestic ceramic to be measured in a box body of a measuring device, and fastening the domestic ceramic to be measured through a carrying part of the measuring device; secondly, acquiring a contour image of the domestic ceramic to be measured through a camera and a light source part of the measuring device, obtaining pixel coordinates of the leftmost upper point and the rightmost upper point of the domestic ceramic to be measured through an image processing procedure, and converting the pixel coordinates into pulse coordinates through a coordinate conversion procedure; then, displacing a detection part of the measuring device to a specified position through a feeding part of the measuring device according to the pulse coordinates, and acquiring and processing data of the outer aperture and the edge height of the domestic ceramic to be measured; and finally transmitting the measurement results to a controller component of the measuring device. The measuring method is convenient to use, safe and reliable, and can greatly improve the detection efficiency of the appearance defects of the domestic ceramics, so that the measuring method has wide market prospect.

Description

Method for measuring height difference and outer aperture difference of domestic ceramic edge

Technical Field

The utility model belongs to the technical field of domestic ceramic detection, and particularly relates to a method for measuring the height difference of a domestic ceramic mouth edge and the difference of an outer diameter of a domestic ceramic mouth edge.

Background

In the deformation detection method of the daily ceramic ware, the height difference of the edge of the mouth and the diameter difference of the outer mouth are specified as indexes for measuring the deformation of the daily ceramic ware. The lip height difference refers to the difference between the maximum height and the minimum height of a point on the lip relative to a reference plane, and the outer diameter difference refers to the difference between the maximum diameter and the minimum diameter formed by the corresponding point on the lip.

At present, the detection of the two indexes is mainly completed manually, namely, on a reference plane, the daily ceramic ware to be detected is rotated, and the values of the height and the caliber of the measuring tool observation port are depended on. This measurement method has the following problems:

1) the measurement accuracy is influenced by more subjective factors. Such as: subjective factors such as inclination, angle change of human observation, environment light change influence people's observation result is put to the measuring tool, and these all can all produce the influence to final measurement accuracy, are difficult to accomplish in the measurement process and all carry out the precision measurement to the oral edge, and measurement accuracy stability is relatively poor.

2) The measurement process needs to manually rotate the ceramic ware, different measuring tools are adopted for the daily ceramic ware with different ware shapes, the measurement of the height difference of the mouth edge and the measurement of the diameter difference of the outer mouth can not be carried out simultaneously, and the factors cause that the efficiency is lower in the measurement process of the daily ceramic ware, and the measurement implementation process is troublesome.

Disclosure of Invention

The utility model provides a convenient, safe and reliable method for measuring the height difference of the edge of the domestic ceramic mouth and the diameter difference of the outer mouth in order to overcome the problems of the prior art.

The technical scheme of the utility model is as follows: a method for measuring the height difference and the outer aperture difference of a domestic ceramic mouth edge is characterized by comprising the following steps:

the method comprises the following steps: placing the domestic ceramic to be measured into a box body of a measuring device, and fastening the domestic ceramic to be measured through a carrying part of the measuring device;

step two: after the feeding component is driven to return to the zero position, acquiring a profile image of the domestic ceramic to be measured through a camera and a light source component of the measuring device, acquiring pixel coordinates of the leftmost upper point and the rightmost upper point of the domestic ceramic to be measured through an image processing procedure, and converting the pixel coordinates of the profile image of the domestic ceramic to be measured into pulse coordinates through a coordinate conversion procedure;

step three: displacing a detection part of the measuring device to a specified position through a feeding part of the measuring device according to the pulse coordinates;

step four: the data of the outer aperture and the height of the edge of the domestic ceramic to be measured are collected and processed by the detection part of the measuring device and are transmitted to the controller part of the measuring device.

Measuring device's box is the cuboid structure, and its bottom is provided with bottom plate one, and the rear portion is provided with the backplate, the left part is provided with left side board, the right part is provided with right side board, the top is provided with the roof, the front portion is provided with left front bezel and right front bezel, the left end movable mounting of left front bezel is on the front end of left side board, and the right-hand member movable mounting of right front bezel is on the front end of right side board.

The object carrying part of the measuring device is composed of a rotary table, a vacuum suction nozzle and a vacuum pump, the vacuum suction nozzle is arranged at the top of the rotary table, the vacuum pump is arranged inside the rotary table, and a connecting pipe is arranged between the vacuum suction nozzle and the vacuum pump.

The light source component of the measuring device consists of a first light source and a second light source; the camera of the measuring device comprises a camera body and a lens, wherein the camera body is a large constant MER-500-14U3M/C type industrial camera with 500 ten thousand pixels, and the lens is a large constant H0514-MP2 type lens; the controller part of the measuring device consists of an STM32 single chip microcomputer, a NanoPC-T4 host, a display screen, keys and a light source controller, wherein the STM32 single chip microcomputer, the display screen and the keys are respectively connected with the NanoPC-T4 host through signal lines, and the light source controller is connected with the light source part through the signal lines.

The feeding component of the measuring device consists of a feeding device I, a feeding device II, a feeding device III and a feeding device IV,

the feeding device I comprises a stepping motor I, a coupling I, a screw rod I, a moving block I, a support I and a horizontal limit switch I, wherein the support I comprises a bottom plate II, a side plate I, a side plate II and a middle plate I, a dovetail convex groove I is arranged at the top of the bottom plate II, a groove I is arranged at the bottom of the moving block I, a hole with internal threads is formed in the top of the moving block I, and a through hole with internal threads is formed in the middle of the moving block I; the first stepping motor is arranged on the outer side of the first side plate, the first coupling is arranged between the first side plate and the first middle plate, the first screw rod is arranged between the first middle plate and the second side plate, the first stepping motor is connected with the first screw rod through the first coupling, the first moving block is arranged on the first screw rod through a through hole, a first groove at the bottom of the first moving block is matched with a first dovetail convex groove, and the first horizontal limit switch is arranged on the upper portion of the inner side of the second side plate;

the feeding device II comprises a stepping motor II, a coupling II, a screw rod II, a moving block II, a support II and a horizontal limit switch II, wherein the support II comprises a bottom plate III, a side plate IV and a middle plate II, a dovetail convex groove II is arranged at the top of the bottom plate III, a groove II is arranged at the bottom of the moving block II, a hole with internal threads is formed in the top of the moving block II, and a through hole with internal threads is formed in the middle of the moving block II; the second stepping motor is arranged on the outer side of the third side plate, the second coupling is arranged between the third side plate and the second middle plate, the second screw rod is arranged between the second middle plate and the fourth side plate, the second stepping motor is connected with the second screw rod through the second coupling, the second moving block is arranged on the second screw rod through a through hole, a groove II in the bottom of the second moving block is matched with a dovetail convex groove II, and the second horizontal limit switch is arranged on the upper portion of the inner side of the fourth side plate;

the feeding device III is composed of a stepping motor III, a coupling III, a screw rod III, a moving block III, a support III and a vertical limit switch I, wherein the support III comprises a bottom plate IV, a side plate V, a side plate VI and a middle plate III, a dovetail convex groove III is formed in the top of the bottom plate IV, a groove III is formed in the bottom of the moving block III, and a through hole with internal threads is formed in the middle of the moving block III; the three-phase stepping motor is connected with the three-phase lead screw through the three-phase coupling, the three-motion block is arranged on the three-lead screw through a through hole, a groove three in the bottom of the three-lead screw is matched with a dovetail convex groove three, and the first vertical limit switch is arranged at the left part of the inner side of the six side plates;

the feeding device IV comprises a stepping motor IV, a coupling IV, a screw rod IV, a moving block IV, a support IV and a vertical limit switch II, wherein the support IV comprises a bottom plate V, a side plate VII, a side plate VIII and a middle plate IV, a dovetail convex groove IV is formed in the top of the bottom plate V, a groove IV is formed in the bottom of the moving block IV, and a through hole with internal threads is formed in the middle of the moving block IV; the four stepping motors are arranged on the outer sides of the seven side plates, the four couplers are arranged between the seven side plates and the four middle plates, the four lead screws are arranged between the four middle plates and the eight side plates and extend to the outside of the eight side plates, the four stepping motors are connected with the four lead screws through the four couplers, the four moving blocks are arranged on the four lead screws through holes, grooves in the bottoms of the four moving blocks are matched with the four dovetail convex grooves, and the two vertical limit switches are arranged on the right parts of the inner sides of the seven side plates.

The detection part of the measuring device comprises an outer caliber detection device and a mouth edge height detection device, the outer caliber detection device is composed of an outer caliber displacement sensor and an outer caliber cylinder, a pre-tightening spring I and an external thread I are arranged on an output shaft of the outer caliber displacement sensor, a hole with an internal thread is arranged in the middle of the outer caliber cylinder, and the outer caliber cylinder is arranged on the external thread I of the output shaft of the outer caliber displacement sensor through the hole; the mouth edge height detection device is composed of a mouth edge displacement sensor and a mouth edge cylinder, a second pre-tightening spring and a second external thread are arranged on an output shaft of the mouth edge displacement sensor, a hole with an internal thread is formed in the middle of the mouth edge cylinder, and the mouth edge cylinder is arranged on the second external thread of the output shaft of the mouth edge displacement sensor through the hole.

The turntable of the object carrying part is arranged at the front end of the top of the first box bottom plate, the controller part is arranged on the outer surface of the right side plate of the box, the first feeding device is arranged at the rear end of the left side of the top of the first box bottom plate, the second feeding device is arranged at the rear end of the right side of the top of the first box bottom plate, a screw rod three outside a sixth side plate of the third feeding device is connected with a hole with internal threads at the top of a moving block I of the first feeding device, a screw rod four outside an eighth side plate of the fourth feeding device is connected with a hole with internal threads at the top of a moving block II of the second feeding device, an outer aperture displacement sensor of the outer aperture detection device is connected with a moving block three phases of the third feeding device through an outer aperture connecting piece, and an aperture displacement sensor of the aperture height detection device is connected with a moving block four phases of the fourth feeding device through an aperture connecting piece; the first horizontal limit switch and the first vertical limit switch form a first stepping zero position for detecting the outer aperture difference, and the second horizontal limit switch and the second vertical limit switch form a second stepping zero position for detecting the height difference of the mouth edge; the camera is arranged on the back plate of the box body; the utility model discloses a displacement sensor, including a left front bezel of box, a right front bezel of box, a STM32 singlechip, a horizontal limit switch, a vertical limit switch, a light source I sets up at box left front bezel inboard, a light source II sets up at box right front bezel inboard, the NanoPC-T4 host computer is connected with the camera through the signal line, the STM32 singlechip is connected with a stepper motor signal line, a stepper motor two signal lines, a stepper motor four signal line, vacuum pump control line, outer aperture displacement sensor signal output part and mouth are followed displacement sensor signal output part, a horizontal limit switch signal line, a horizontal limit switch two signal line, a vertical limit switch two signal line and is connected, the axis of outer aperture displacement sensor intersects perpendicularly with the central line of revolving stage, mouth is followed displacement sensor's axis and is parallel with the central line of revolving stage, measuring device's controller part links to each other with external power source.

The image processing procedure in the second step comprises the following steps:

1): converting the shot image into a grayscale image, and performing binarization processing on the obtained daily ceramic region R to be detected, namely for each point v (x, y) in the image, if v (x, y) ≧ 255, otherwise v (x, y) =0, wherein (x, y) represents a pixel point with column coordinates x and row coordinates y, v represents the grayscale of the point, and th is a settable threshold value in the range of 100-;

2): extracting the boundary of the daily ceramic region R to be detected, wherein the method for extracting the boundary is completed through morphological operation,

wherein β (R) represents the boundary of region R, ϴ represents the morphological etching operation, a represents the structural element;

3): the obtained daily ceramic boundary beta (R) is calculated to obtain the pixel coordinate of the leftmost upper point of the daily ceramic boundary beta (R) as P_LT= ({ (x, y) | (x, y) ∈ β (R), min (y + α x) }, whose rightmost upper point pixel coordinate is, P_RT= { (x, y) | (x, y) ∈ β (R), min (y- α x) }, where min is a minimum function, α is a settable coefficient, and is between 0.2 and 1;

the step of the coordinate conversion process in the step two is as follows:

1): a first plane pulse coordinate system is formed by the first feeding device and the third feeding device,

the horizontal axis of the origin of the first plane pulse coordinate system is the position of the first horizontal limit switch, the vertical axis of the origin is the position of the first vertical limit switch, the horizontal direction is defined as the right direction, and the vertical direction is defined as the upward direction; a second plane pulse coordinate system is formed by the second feeding device and the fourth feeding device, the horizontal coordinate of the origin of the second plane pulse coordinate system is the position of the second horizontal limit switch, the vertical coordinate of the origin is the position of the second vertical limit switch, the left direction of the horizontal direction is defined as the positive direction, and the down direction of the vertical direction is defined as the positive direction; calibrating pixels and pulses on the plane pulse coordinate system I and the plane pulse coordinate system II to obtain a transformation equation taking the pulses as dependent variables and the pixels as independent variables;

2): according to a transformation equation, the leftmost upper point P in the daily ceramic boundary beta (R)_LTAnd the upper rightmost point P_RTSubstituting the equation to respectively form a pulse coordinate to which the stepping motor III of the feeding device III should operate and a pulse coordinate to which the stepping motor II of the feeding device II should operate;

the step of returning the zero position of the feeding part in the step two is as follows:

1): a step motor III of the driving feeding device III drives a moving block III to run in the negative direction until the position of a vertical limit switch I is reached;

2): a step motor I of the driving feeding device I drives a motion block I to run in a negative direction until the position of a horizontal limit switch I is reached;

3): a second stepping motor of the second driving feeding device drives a second moving block to run in a negative direction until the second moving block reaches the position of a second horizontal limit switch;

4): a step motor four of the driving feeding device four drives a moving block four to run negatively until the position of a vertical limit switch two is reached;

the step of moving the detection part of the measuring device to the designated position in the third step comprises the following steps:

1): a step motor three driving motion block three of the driving feeding device three runs to reach the pulse coordinate calculated by the transformation equation;

2): a first stepping motor for driving a first feeding device props the outer-aperture cylinder against the edge of the daily ceramic port to be detected until the displacement of the outer-aperture displacement sensor reaches a position half of the measuring range;

3): a second stepping motor of the second driving feeding device drives a second motion block to run to reach the pulse coordinate calculated by the transformation equation;

4): and driving a stepping motor IV of the feeding device IV to enable the port edge to abut against the edge of the domestic ceramic port to be detected until the displacement of the port edge displacement sensor reaches a position of half of the measuring range.

The calibration steps between the pixels and the pulses are as follows:

1) dividing the horizontal direction and the vertical direction of the plane pulse coordinate system I or the plane pulse coordinate system II into N equal parts according to the pulse number in the stroke, wherein N is 2-10, thus forming N²The outer caliber connecting piece or the opening edge connecting piece is provided with a marking point which can be marked by a special color pen;

2): the first stepping motor and the third stepping motor return to a first stepping zero position, and the second stepping motor and the fourth stepping motor return to a second stepping zero position;

3): the controller part drives the first stepping motor, the third stepping motor, the second stepping motor and the fourth stepping motor to run to a point needing to be calibrated, the camera takes pictures, pixel coordinates corresponding to the marked point are obtained and recorded, and the number of running pulses of the current stepping motor is recorded;

4): repeating the step 3) until N²The data of each index point is recorded, so that a set R of pulse coordinates can be obtained_pulses=｛(mx_i,my_j) I, j ∈ Z,0 ≦ i, j ≦ N-1 } and a set R of corresponding pixel coordinates_img=｛(vx_i,vy_j) |i,j∈Z,0≦i,j≦N-1｝；

5): fitting the data obtained in the step 4) by using my as a dependent variable and vx and vy as independent variables and adopting a least square method to fit a model: my = a × vx + b × vy + c, where (a, b, c) is the parameter to be fitted, mx is the dependent variable, vx and vy are the independent variables, and the model is fitted using the least squares method: mx = d x vx + e vy + f, where (d, e, f) is the parameter to be fitted.

The data acquisition and processing steps of the external diameter of the domestic ceramic to be detected are as follows:

1): according to the outer aperture circle connected with the outer aperture displacement sensorThe horizontal distance between the initial position of the right edge of the cylinder and the center of the rotary table and the pulse number of the first stepping motor of the feeding device when the first stepping motor runs to the measuring position are calculated, and the distance between the center of the rotary table and the right edge of the outer-diameter cylinder at present is used as the initial diameter r₀；

2): the displacement data measured by the outer aperture displacement sensor is represented by an array kdata [ N ], wherein N represents the number of data, the angular speed of the turntable is represented by omega, the data acquisition period measured by the outer aperture displacement sensor is represented by T, and the center of the turntable is taken as the origin of coordinates, so that the coordinates of the nth (N belongs to [0, N)) point of the excircle profile of the daily ceramic to be measured are as follows: ((kdata [ N ] + r0) cosn ω T, (kdata [ N ] + r0) sinn ω T), thereby obtaining a domestic ceramic excircle contour coordinate point set PS with a set size N;

3): for the nth point of the PS, finding out a point with the maximum Euclidean distance from the nth point of the PS within the range of the diameter of (N/10) by taking the point with the position of m = (N + N/2)% N in the PS as the center, and taking the Euclidean distance between the points as the outer diameter corresponding to the nth point of the PS;

4): repeating the previous step until all points in the PS are processed, finding out the maximum value and the minimum value of the outer aperture, and taking the difference value as the final result of the outer aperture difference;

the data acquisition and processing steps of the height of the edge of the domestic ceramic mouth to be detected are as follows:

1) in the process that a rotary table of a carrying part of the measuring device rotates for one circle, the port edge displacement sensor generates corresponding displacement along the axis, the output of the port edge displacement sensor and the displacement form a linear relation voltage quantity, a controller part of the measuring device acquires voltage data output by the port edge displacement sensor at regular time, and the timing period is between 0.1ms and 10 ms;

2) after the collection is finished, calculating the mean value mu and the variance sigma of the collected data according to a probability statistics theory, and eliminating the data with the distance from the mean value exceeding 10 times of the variance in the data, wherein the calculation formula of the mean value is as follows:

the variance is calculated by the formula:

wherein x is_iRepresenting the ith data collected;

3) in the rest data, the maximum value and the minimum value are found, and the absolute value of the difference is used as the final result of the height difference of the mouth edge.

The vacuum suction nozzle is made of rubber.

The outer caliber cylinder and the mouth edge cylinder are made of stainless steel, the roughness of the outer surface of the outer caliber cylinder and the outer surface of the mouth edge cylinder are Ra0.2, and the hardness of the outer caliber cylinder and the mouth edge cylinder is HRC 45-50.

The surface roughness of the rotary table is Ra 0.8, and the flatness error is 0.1 mm.

Compared with the prior art, the technical scheme provided by the utility model has the following remarkable effects.

According to the method for measuring the height difference and the outer aperture difference of the edge of the domestic ceramic, disclosed by the utility model, a user only needs to place the domestic ceramic to be measured on the rotary table, shoot an outer contour image of the domestic ceramic through the camera, convert a pixel coordinate of the image into a pulse coordinate, respectively move the edge displacement sensor and the outer aperture displacement sensor to specified positions through the feeding part according to the pulse coordinate, and quickly obtain the edge height difference and the outer aperture difference of the domestic ceramic by acquiring the measurement data of the edge height and the outer aperture of the domestic ceramic, so that the detection efficiency of the appearance defects of the domestic ceramic is greatly improved, and the method has a wide market prospect.

Drawings

FIG. 1 is a schematic view of the overall structure of the measuring device of the present invention;

FIG. 2 is a schematic structural view of a carrier member;

FIG. 3 is a schematic diagram of the structure of the controller components;

FIG. 4 is a first schematic structural diagram of a detection component;

FIG. 5 is a second schematic structural view of the detecting member;

FIG. 6 is a first schematic structural diagram of a feeding component;

FIG. 7 is a second schematic structural view of the feeding member;

FIG. 8 is a third schematic structural view of the feeding member;

fig. 9 is a fourth schematic structural view of the feeding member.

Detailed Description

For a further understanding of the utility model, reference will now be made in detail to the following examples and accompanying drawings, in which:

a method for measuring the height difference and the outer aperture difference of a domestic ceramic mouth edge comprises the following steps:

the method comprises the following steps: placing the domestic ceramic 22 to be measured in a box body 1 of the measuring device, and fastening the domestic ceramic 22 to be measured through a carrying part 2 of the measuring device;

step two: acquiring a contour image of the domestic ceramic 22 to be measured through a camera 6 and a light source part of the measuring device, acquiring pixel coordinates of the leftmost upper point and the rightmost upper point of the domestic ceramic 22 to be measured through an image processing procedure, and converting the pixel coordinates of the contour image of the domestic ceramic 22 to be measured into pulse coordinates through a coordinate conversion procedure;

The box body 1 is of a cuboid structure, a bottom plate 101 is welded at the bottom of the box body, a back plate 102 is welded at the rear portion, a left side plate 103 is welded at the left portion, a right side plate 104 is welded at the right portion, a top plate 105 is welded at the top portion, the left end of a left front plate 106 is movably mounted at the front end of the left side plate 103 through a fixing shaft, and the right end of a right front plate 107 is movably mounted at the front end of the right side plate 104 through the fixing shaft.

The object carrying component 2 is composed of a turntable 201, a vacuum suction nozzle 202 and a vacuum pump 203, the vacuum suction nozzle 202 is fixed at the top of the turntable 201 through a screw, the vacuum pump 203 is fixed inside the turntable 201 through a screw, and the vacuum suction nozzle 202 and the vacuum pump 203 are provided with a connecting pipe.

The light source component of the measuring device consists of a first light source 20 and a second light source 21; the camera 6 of the measuring device comprises a camera body and a lens, wherein the camera body is a large constant MER-500-14U3M/C type industrial camera with 500 ten thousand pixels, and the lens is a large constant H0514-MP2 type lens.

The feeding component of the measuring device consists of a feeding device I8, a feeding device II 9, a feeding device III 10 and a feeding device IV 11,

the feeding device I8 is composed of a stepping motor I801, a coupling I802, a screw rod I803, a moving block I804, a support I805 and a horizontal limit switch I812, wherein the support I805 comprises a bottom plate II 806, a side plate I807, a side plate II 808 and a middle plate I809, a dovetail convex groove I810 is fixed at the top of the bottom plate II 806 through a screw, a groove I811 is cast at the bottom of the moving block I804, a hole with internal threads is cast at the top, and a through hole with internal threads is cast in the middle; the first stepping motor 801 is fixed on the outer side of the first side plate 807, the first coupling 802 is fixed between the first side plate 807 and the first middle plate 809, the first screw rod 803 is fixed between the first middle plate 809 and the second side plate 808, the first stepping motor 801 is connected with the first screw rod 803 through the first coupling 802, the first moving block 804 is movably fixed on the first screw rod 803 through a through hole, a first groove 811 at the bottom of the first moving block is matched with a first dovetail convex groove 810, and a first horizontal limit switch 812 is fixed on the upper portion of the inner side of the second side plate 808 through a screw;

the feeding device II 9 is composed of a stepping motor II 901, a coupling II 902, a screw rod II 903, a moving block II 904, a support II 905 and a horizontal limit switch II 912, wherein the support II 905 comprises a bottom plate III 906, a side plate III 907, a side plate IV 908 and a middle plate II 909, a dovetail convex groove II 910 is fixed at the top of the bottom plate III 906 through a screw, a groove II 911 is poured at the bottom of the moving block II 904, a hole with internal threads is poured at the top of the moving block II, and a through hole with internal threads is poured at the middle of the moving block II; the second stepping motor 901 is fixed on the outer side of the third side plate 907, the second coupling 902 is fixed between the third side plate 907 and the second middle plate 909, the second screw rod 903 is fixed between the second middle plate 909 and the fourth side plate 908, the second stepping motor 901 is connected with the second screw rod 903 through the second coupling 902, the second moving block 904 is movably fixed on the second screw rod 903 through a through hole, a second bottom groove 911 of the second moving block is matched with a second dovetail convex groove 910, and a second horizontal limit switch 912 is fixed on the upper portion of the inner side of the fourth side plate 908 through screws;

the feeding device III 10 comprises a stepping motor III 1001, a coupling III 1002, a screw rod III 1003, a moving block III 1004, a support III 1005 and a vertical limit switch I1012, wherein the support III 1005 comprises a bottom plate IV 1006, a side plate V1007, a side plate VI 1008 and a middle plate III 1009, a dovetail convex groove III 1010 is fixed at the top of the bottom plate IV 1006 through a screw, a groove III 1011 is cast at the bottom of the moving block III 1004, and a through hole with internal threads is cast in the middle of the moving block III 1004; the three stepping motors 1001 are fixed on the outer sides of the five side plates 1007, the three couplers 1002 are fixed between the five side plates 1007 and the three middle plates 1009, the three screw rods 1003 are fixed between the three middle plates 1009 and the six side plates 1008 and extend to the outer parts of the six side plates 1008, the three stepping motors 1001 are connected with the three screw rods 1003 through the three couplers 1002, the three moving blocks 1004 are movably fixed on the three screw rods 1003 through holes, the three grooves 1011 at the bottoms of the three moving blocks are matched with the three dovetail convex grooves 1010, and the first vertical limit switches 1012 are fixed on the left parts of the inner sides of the six side plates 1008 through screws;

the feeding device IV 11 is composed of a stepping motor IV 1101, a coupling IV 1102, a screw rod IV 1103, a moving block IV 1104, a support IV 1105 and a vertical limit switch II 1112, wherein the support IV 1105 comprises a bottom plate V1106, a side plate VII 1107, a side plate VIII 1108 and a middle plate IV 1109, a dovetail convex groove IV 1110 is fixed at the top of the bottom plate V1106 through screws, a groove IV 1111 is cast at the bottom of the moving block IV 1104, and a through hole with internal threads is cast in the middle of the moving block IV 1104; the four step motors 1101 are fixed on the outer side of the side plate seven 1107, the four couplers 1102 are fixed between the side plate seven 1107 and the four middle plates 1109, the four screw rods 1103 are fixed between the four middle plates 1109 and the eight side plate 1108 and extend to the outside of the eight side plate 1108, the four step motors 1101 are connected with the four screw rods 1103 through the four couplers 1102, the four motion blocks 1104 are movably fixed on the four screw rods 1103 through holes, the four bottom grooves 1111 of the four motion blocks are matched with the four dovetail convex grooves 1110, and the two vertical limit switches 1112 are fixed on the right portion of the inner side of the side plate seven 1107 through screws.

The detection part comprises an outer caliber detection device and a mouth edge height detection device, the outer caliber detection device is composed of an outer caliber displacement sensor 12 and an outer caliber cylinder 13, a pre-tightening spring I14 is sleeved on an output shaft of the outer caliber displacement sensor 12, an external thread I15 is poured on the top of the output shaft, a hole with an internal thread is poured in the middle of the outer caliber cylinder 13, and the outer caliber cylinder 13 is fixed on the external thread I15 of the output shaft of the outer caliber displacement sensor 12 through the hole; the mouth edge height detection device is composed of a mouth edge displacement sensor 16 and a mouth edge cylinder 17, a second pre-tightening spring 18 and a second external thread 19 are sleeved on an output shaft of the mouth edge displacement sensor 16, a hole with an internal thread is poured in the middle of the mouth edge cylinder 17, and the mouth edge cylinder 17 is fixed on the second external thread 19 of the output shaft of the mouth edge displacement sensor 16 through the hole.

The controller part 3 of the measuring device is composed of an STM32 single chip microcomputer, a NanoPC-T4 host, a display screen, keys and a light source controller, wherein the STM32 single chip microcomputer, the display screen and the keys are respectively connected with the NanoPC-T4 host through signal lines, and the light source controller is connected with the light source part through the signal lines.

The turntable 201 of the object carrying component is fixed at the front end of the top of the box body bottom plate I101 through a bolt, the controller component 3 is fixed at the outer surface of the box body right side plate 104 through a screw, the feeding device I8 is fixed at the left rear end of the top of the box body bottom plate I101 through a bolt, the feeding device II 9 is fixed at the right rear end of the top of the box body bottom plate I101 through a bolt, a screw rod III 1003 of the feeding device III 10 outside a side plate VI 1008 is fixedly connected with a hole with internal threads at the top of a moving block I804 of the feeding device I8, a screw rod IV 1103 outside a side plate eight 1108 of the feeding device IV 11 is connected with a hole with internal threads at the top of a moving block II 904 of the feeding device II 9, one end of the outer diameter connecting piece 5 is connected with an outer diameter displacement sensor 12 through a bolt, and the other end of the outer diameter connecting piece is connected with a moving block III 1004 of the feeding device III 10 through a bolt, one end of the mouth edge connecting piece 7 is connected with the mouth edge displacement sensor 16 through a bolt, the other end of the mouth edge connecting piece is connected with a moving block IV 1104 of the feeding device IV 11 through a screw, the horizontal limit switch I812 and the vertical limit switch I1012 form a stepping zero position I for detecting the difference of the outer mouth diameters, and the horizontal limit switch II 912 and the vertical limit switch II 1112 form a stepping zero position II for detecting the difference of the height of the mouth edges; the camera 6 is fixed on the box body back plate 102 through bolts; the first light source 20 is fixed on the inner side of a left front plate 106 of the box body through a bolt, the second light source 21 is fixed on the inner side of a right front plate 107 of the box body through a bolt, the NanoPC-T4 host is connected with the camera 6 through a signal line, the STM32 single chip microcomputer is connected with a first stepping motor 801 signal line, a second stepping motor 901 signal line, a third stepping motor 1001 signal line, a fourth stepping motor 1101 signal line, a vacuum pump 203 control line, an outer aperture displacement sensor 12 signal output end and an edge displacement sensor 16 signal output end, a first horizontal limit switch 812 signal line, a second horizontal limit switch 912 signal line, a first vertical limit switch 1012 signal line and a second vertical limit switch 1112 signal line through signal lines.

The axis of the outer aperture displacement sensor 12 is vertically intersected with the central line of the turntable 201, the aperture is parallel to the central line of the turntable 201 along the axis of the displacement sensor 16, and the controller part 3 of the measuring device is connected with an external power supply.

The vacuum nozzle 202 is made of rubber.

The outer caliber cylinder 13 and the mouth edge cylinder 17 are made of stainless steel, the roughness of the outer surface of the outer caliber cylinder is Ra0.2, and the hardness of the outer caliber cylinder is HRC 45-50.

The surface roughness of the turntable 201 is Ra 0.8, and the flatness error is 0.1 mm.

1): converting the shot image into a gray image, and performing binarization processing on the obtained daily ceramic area R to be measured, namely, for each point v (x, y) in the image, if v (x, y) ≧ th, v (x, y) =255, otherwise v (x, y) =0, wherein (x, y) represents a pixel point with a column coordinate of x and a row coordinate of y, v represents the gray of the point, and th is a settable threshold value, and the range is 150;

where β (R) represents the boundary of region R, ϴ represents the morphological etching operation, a represents a structural element, being a rectangle of size 3 × 3;

3): the obtained daily ceramic boundary beta (R) is calculated to have the pixel coordinate of the leftmost upper point as P_LT= ({ (x, y) | (x, y) ∈ β (R), min (y + α x) }, whose rightmost upper point pixel coordinate is, P_RT= ({ (x, y) | (x, y) ∈ β (R), min (y- α x) }, where min is a minimum function and α is a settable coefficient, between 0.5;

the step of the coordinate conversion process in the step two is as follows:

1): a first plane pulse coordinate system is formed by the first feeding device 8 and the third feeding device 10, the horizontal coordinate of the origin of the first plane pulse coordinate system is the position of the first horizontal limit switch 812, the vertical coordinate of the origin is the position of the first vertical limit switch 1012, the right direction of the horizontal direction is defined as a positive direction, and the upward direction of the vertical direction is defined as a positive direction; a second plane pulse coordinate system is formed by the second feeding device 9 and the fourth feeding device 11, the horizontal coordinate of the origin of the second plane pulse coordinate system is the position of the second horizontal limit switch 912, the vertical coordinate of the origin is the second vertical limit switch 1112, the position specifies that the left direction of the horizontal direction is a positive direction, and the downward direction of the vertical direction is a positive direction; calibrating pixels and pulses on the plane pulse coordinate system I and the plane pulse coordinate system II to obtain a transformation equation taking the pulses as dependent variables and the pixels as independent variables;

2): according to a transformation equation, the leftmost upper point P in the daily ceramic boundary beta (R)_LTAnd the upper rightmost point P_RTSubstituting the equation to respectively form a pulse coordinate to which the stepping motor III 1001 of the feeding device III 10 should run and a pulse coordinate to which the stepping motor II 901 of the feeding device II 9 should run;

1): a third step motor 1001 of the third driving feeding device 10 drives a third moving block 1004 to run in a negative direction until reaching the position of a first vertical limit switch 1012;

2): a first stepping motor 801 for driving a first feeding device 8 drives a first moving block 804 to run in a negative direction until a position of a first horizontal limit switch 812 is reached;

3): a second stepping motor 901 of the second driving feeding device 9 drives a second moving block 904 to run in a negative direction until the position of a second horizontal limit switch 912 is reached;

4): a fourth step motor 1101 of the fourth driving feeding device 11 drives a fourth motion block 1104 to run in the negative direction until a second vertical limit switch 1112 is reached;

1): a step motor III 1001 of the driving feeding device III 10 drives a motion block III 1004 to run to reach the pulse coordinates calculated by the transformation equation;

2): a step motor I801 driving a feeding device I8 pushes the outer aperture cylinder 13 against the edge of the domestic ceramic orifice to be measured until the displacement of the outer aperture displacement sensor 12 reaches a position of half of the measuring range;

3): a second stepping motor 901 of the second driving feeding device 9 drives a second motion block 904 to run to reach the pulse coordinate calculated by the transformation equation;

4): and driving a stepping motor IV 1101 of the feeding device IV 11 to press the port edge cylinder 17 against the domestic ceramic port edge to be measured until the displacement of the port edge displacement sensor 16 reaches the position of half the measuring range.

The calibration steps between the pixels and the pulses are as follows:

1) dividing a plane pulse coordinate system I or a plane pulse coordinate system II into N equal parts in the horizontal direction and the vertical direction according to the pulse number in the stroke, and when N is 5, forming 25 points to be calibrated, wherein a mark point is arranged at the outer aperture connecting piece 5 or the opening edge connecting piece 7 and can be marked by a special color pen;

2): the first stepping motor 801 and the third stepping motor 1001 return to a first stepping zero position, and the second stepping motor 901 and the fourth stepping motor 1101 return to a second stepping zero position;

3): the controller part 3 drives the first stepping motor 801, the third stepping motor 1001, the second stepping motor 901 and the fourth stepping motor 1101 to run to a point needing to be calibrated, the camera 6 takes a picture, obtains and records a pixel coordinate corresponding to a mark point, and records the number of pulses of the current stepping motor in running;

4): repeating the step 3) until 25 index point data are recorded, so as to obtain a set R of pulse coordinates_pulses=｛(mx_i,my_j) I, j ∈ Z,0 ≦ i, j ≦ N-1 } and a set R of corresponding pixel coordinates_img=｛(vx_i,vy_j) |i,j∈Z,0≦i,j≦N-1｝；

1): according to the horizontal distance between the initial position of the right edge of the outer aperture cylinder 13 connected with the outer aperture displacement sensor 12 and the center of the rotary table 201 and the pulse number of the stepping motor I801 of the feeding device I8 running to the measuring position, calculating the distance between the center of the rotary table 201 and the right edge of the outer aperture cylinder 13 at present as the initial diameter r₀；

2): the displacement data measured by the outer caliber displacement sensor 12 is represented by an array kdata [ N ], wherein N =1000, the angular velocity of the turntable 201 is represented by ω, the data acquisition period measured by the outer caliber displacement sensor 12 is represented by T, T =2ms, and with the center of the turntable 201 as the origin of coordinates, the coordinates of the nth (N epsilon [0, N)) point of the excircle profile of the domestic ceramic to be measured are: ((kdata [ N ] + r0) cosn ω T, (kdata [ N ] + r0) sinn ω T), thereby obtaining a domestic ceramic excircle contour coordinate point set PS with a set size N;

3): for the nth point of the PS, taking a point with the position of m = (N + N/2)% N in the PS as the center, finding out a point with the maximum Euclidean distance with the nth point of the PS within the range of the diameter of 100, and taking the Euclidean distance between the points as an outer diameter corresponding to the position of the nth point of the PS;

the method comprises the following steps of collecting and processing data of the edge height of the domestic ceramic mouth to be detected:

1) in the process that the turntable 201 of the object carrying part of the measuring device rotates for one circle, the port edge displacement sensor 16 generates corresponding displacement along the axis, the port edge displacement sensor 16 outputs voltage quantity which is in linear relation with the displacement, the controller part 3 of the measuring device collects voltage data output by the port edge displacement sensor 16 at regular time, and the timing period is 5 ms;

the variance is calculated as:

wherein x is_iRepresenting the ith data collected;

in the rest data, the maximum value and the minimum value are found, and the absolute value of the difference is used as the final result of the height difference of the mouth edge.

The programs used in the image processing process, the coordinate conversion process, the data acquisition and processing process, and the like are written by the inventor in C language or C + + language.

Claims

1. A method for measuring the height difference and the outer aperture difference of a domestic ceramic mouth edge is characterized by comprising the following steps: the method comprises the following steps: placing the domestic ceramic to be measured into a box body of a measuring device, and fastening the domestic ceramic to be measured through a carrying part of the measuring device;

step two: after the feeding part is driven to return to the zero position, acquiring a profile image of the daily ceramic to be measured through a camera and a light source part of the measuring device, obtaining pixel coordinates of the leftmost upper point and the rightmost upper point of the daily ceramic to be measured through an image processing procedure, and converting the pixel coordinates of the profile image of the daily ceramic to be measured into pulse coordinates through a coordinate conversion procedure;

step four: the data of the outer aperture and the height of the edge of the domestic ceramic to be measured are collected and processed by a detection part of the measuring device and are transmitted to a controller part of the measuring device;

the box body (1) of the measuring device is of a cuboid structure, a first bottom plate (101) is arranged at the bottom of the box body, a back plate (102) is arranged at the rear part of the box body, a left side plate (103) is arranged at the left part of the box body, a right side plate (104) is arranged at the right part of the box body, a top plate (105) is arranged at the top of the box body, a left front plate (106) and a right front plate (107) are arranged at the front part of the box body, the left end of the left front plate (106) is movably installed at the front end of the left side plate (103), and the right end of the right front plate (107) is movably installed at the front end of the right side plate (104);

the object carrying component (2) of the measuring device is composed of a rotary table (201), a vacuum suction nozzle (202) and a vacuum pump (203), wherein the vacuum suction nozzle (202) is arranged at the top of the rotary table (201), the vacuum pump (203) is arranged inside the rotary table (201), and a connecting pipe is arranged between the vacuum suction nozzle (202) and the vacuum pump (203);

the light source component of the measuring device is composed of a first light source (20) and a second light source (21); the camera (6) of the measuring device comprises a camera body and a lens, wherein the camera body is a large constant MER-500-14U3M/C model industrial camera with 500 ten thousand pixels, and the lens is a large constant H0514-MP2 model lens; the controller part (3) of the measuring device consists of an STM32 single chip microcomputer, a NanoPC-T4 host, a display screen, keys and a light source controller, wherein the STM32 single chip microcomputer, the display screen and the keys are respectively connected with the NanoPC-T4 host through signal lines, and the light source controller is connected with the light source part through the signal lines;

the feeding part of the measuring device consists of a feeding device I (8), a feeding device II (9), a feeding device III (10) and a feeding device IV (11), wherein the feeding device I (8) consists of a stepping motor I (801), a coupling I (802), a screw rod I (803), a moving block I (804), a support I (805) and a horizontal limit switch I (812), the support I (805) comprises a bottom plate II (806), a side plate I (807), a side plate II (808) and a middle plate I (809), a dovetail convex groove I (810) is arranged at the top of the bottom plate II (806), a groove I (811) is arranged at the bottom of the moving block I (804), a hole with internal threads is formed in the top of the moving block I, and a through hole with internal threads is formed in the middle of the moving block I (804); the first stepping motor (801) is arranged on the outer side of the first side plate (807), the first coupling (802) is arranged between the first side plate (807) and the first middle plate (809), the first screw rod (803) is arranged between the first middle plate (809) and the second side plate (808), the first stepping motor (801) is connected with the first screw rod (803) through the first coupling (802), the first moving block (804) is arranged on the first screw rod (803) through a through hole, a first groove (811) at the bottom of the first moving block is matched with a first dovetail convex groove (810), and a first horizontal limiting switch (812) is arranged on the upper portion of the inner side of the second side plate (808);

the feeding device II (9) is composed of a stepping motor II (901), a coupler II (902), a screw rod II (903), a moving block II (904), a support II (905) and a horizontal limit switch II (912), wherein the support II (905) comprises a bottom plate III (906), a side plate III (907), a side plate IV (908) and a middle plate II (909), a dovetail convex groove II (910) is formed in the top of the bottom plate III (906), a groove II (911) is formed in the bottom of the moving block II (904), a hole with internal threads is formed in the top of the moving block II, and a through hole with internal threads is formed in the middle of the moving block II; the second stepping motor (901) is arranged on the outer side of the third side plate (907), the second coupling (902) is arranged between the third side plate (907) and the second middle plate (909), the second screw rod (903) is arranged between the second middle plate (909) and the fourth side plate (908), the second stepping motor (901) is connected with the second screw rod (903) through the second coupling (902), the second moving block (904) is arranged on the second screw rod (903) through a through hole, the second bottom groove (911) of the second moving block is matched with the second dovetail convex groove (910), and the second horizontal limit switch (912) is arranged on the upper portion of the inner side of the fourth side plate (908);

the feeding device III (10) is composed of a stepping motor III (1001), a coupling III (1002), a screw rod III (1003), a moving block III (1004), a support III (1005) and a vertical limit switch I (1012), wherein the support III (1005) comprises a bottom plate IV (1006), a side plate V (1007), a side plate VI (1008) and a middle plate III (1009), a dovetail convex groove III (1010) is formed in the top of the bottom plate IV (1006), a groove III (1011) is formed in the bottom of the moving block III (1004), and a through hole with internal threads is formed in the middle of the moving block III (1004); the three-dimensional stepping motor (1001) is arranged on the outer side of the five side plate (1007), the third coupling (1002) is arranged between the five side plate (1007) and the third middle plate (1009), the third screw rod (1003) is arranged between the third middle plate (1009) and the six side plate (1008) and extends to the outside of the six side plate (1008), the three stepping motor (1001) is connected with the third screw rod (1003) through the third coupling (1002), the third moving block (1004) is arranged on the third screw rod (1003) through a through hole, a groove three (1011) at the bottom of the third moving block is matched with a dovetail convex groove three (1010), and the first vertical limit switch (1012) is arranged on the left part of the inner side of the six side plate (1008);

the feeding device IV (11) is composed of a stepping motor IV (1101), a coupling IV (1102), a screw rod IV (1103), a moving block IV (1104), a support IV (1105) and a vertical limit switch II (1112), wherein the support IV (1105) comprises a bottom plate V (1106), a side plate VII (1107), a side plate VIII (1108) and a middle plate IV (1109), the top of the bottom plate V (1106) is provided with a dovetail convex groove IV (1110), the bottom of the moving block IV (1104) is provided with a groove IV (1111), and the middle of the moving block IV (1104) is provided with a through hole with internal threads; the four stepping motors (1101) are arranged on the outer side of the side plate seven (1107), the four couplers (1102) are arranged between the side plate seven (1107) and the middle plate four (1109), the four lead screws (1103) are arranged between the middle plate four (1109) and the side plate eight (1108) and extend to the outer part of the side plate eight (1108), the four stepping motors (1101) are connected with the four lead screws (1103) through the four couplers (1102), the four moving blocks (1104) are arranged on the four lead screws (1103) through holes, bottom grooves (1111) of the four stepping motors are matched with dovetail convex grooves (1110) of the four moving blocks (1104), and the two vertical limit switches (1112) are arranged on the right part of the inner side of the side plate seven (1107);

the detection part of the measuring device comprises an outer caliber detection device and a mouth edge height detection device, the outer caliber detection device is composed of an outer caliber displacement sensor (12) and an outer caliber cylinder (13), a pre-tightening spring I (14) and an external thread I (15) are arranged on an output shaft of the outer caliber displacement sensor (12), a hole with an internal thread is arranged in the middle of the outer caliber cylinder (13), and the outer caliber cylinder (13) is arranged on the external thread I (15) of the output shaft of the outer caliber displacement sensor (12) through the hole; the mouth is followed high detection device and is formed by mouth along displacement sensor (16) and mouth along cylinder (17), be provided with pretension spring two (18) and external screw thread two (19) on the output shaft of mouth along displacement sensor (16), mouth is provided with the hole of taking the internal screw thread along cylinder (17) middle part, mouth is followed cylinder (17) and is passed through the hole setting on mouthful along external screw thread two (19) of displacement sensor's (16) output shaft.

2. The measurement method according to claim 1, characterized in that: the turntable (201) of the object carrying part is arranged at the front end of the top of the first box bottom plate (101), the controller part (3) is arranged on the outer surface of the right side plate (104) of the box, the first feeding device (8) is arranged at the rear left end of the top of the first box bottom plate (101), the second feeding device (9) is arranged at the rear right end of the top of the first box bottom plate (101), a third screw rod (1003) on the outer side of a sixth side plate (1008) of the third feeding device (10) is connected with a hole with internal threads at the top of a first moving block (804) of the first feeding device (8), a fourth screw rod (1103) on the outer side of an eighth side plate (1108) of the fourth feeding device (11) is connected with a hole with internal threads at the top of a second moving block (904) of the second feeding device (9), and an outer aperture displacement sensor (12) of the outer aperture detection device is connected with the third moving block (1004) of the third feeding device (10) through an outer aperture connecting piece (5), the mouth edge displacement sensor (16) of the mouth edge height detection device is connected with a moving block IV (1104) of the feeding device IV (11) through a mouth edge connecting piece (7); the first horizontal limit switch (812) and the first vertical limit switch (1012) form a first stepping zero position for detecting the difference of the outer port diameters, and the second horizontal limit switch (912) and the second vertical limit switch (1112) form a second stepping zero position for detecting the difference of the height of the port edges; the camera (6) is arranged on the box body back plate (102); the device comprises a light source I (20), a light source II (21), a NanoPC-T4 host, a camera (6), an STM32 single chip microcomputer, a stepping motor I (801) signal line, a stepping motor II (901) signal line, a stepping motor III (1001) signal line, a stepping motor IV (1101) signal line, a vacuum pump (203) control line, an outer caliber displacement sensor (12) signal output end and an edge displacement sensor (16) signal output end, a horizontal limit switch I (812) signal line, a horizontal limit switch II (912) signal line, a vertical limit switch I (1012) signal line and a vertical limit switch II (1112) signal line, wherein the light source I (20) is arranged on the inner side of a left front plate (106) of a box body, the light source II (21) is arranged on the inner side of a right front plate (107) of the box body, the NanoPC-T4 host is connected with the camera (6) through signal lines, the STM32 single chip microcomputer is connected with a horizontal limit switch I (812) signal output end, a horizontal limit switch I (812) signal line, a horizontal limit switch I (912) signal line, a vertical limit switch I (1012) signal line, a vertical limit switch I (912) signal line, a vertical limit switch II (102) signal line of a vertical limit switch II (201) signal line of a vertical limit switch I, a vertical limit switch II (200) signal line, a vertical limit switch (201) signal line, a horizontal limit switch II (200) signal line, a vertical limit switch, a horizontal limit switch, a vertical limit switch, a horizontal limit switch, a vertical switch, a horizontal limit switch, a horizontal switch, a vertical switch, a horizontal switch, a vertical switch, a horizontal switch, a vertical switch, a horizontal switch, a vertical switch, a horizontal switch, a vertical switch, a horizontal switch, a vertical switch, a horizontal, the port is parallel to the center line of the rotary table (201) along the axis of the displacement sensor (16), and a controller part (3) of the measuring device is connected with an external power supply.

3. The measurement method according to claim 1, characterized in that: the image processing procedure in the second step comprises the following steps:

1): converting the shot image into a gray image, and performing binarization processing on the obtained daily ceramic area R to be measured, namely for each point v (x, y) in the image, if v (x, y) ≧ th, v (x, y) =255, otherwise v (x, y) =0, wherein (x, y) represents a pixel point with a column coordinate of x and a row coordinate of y, v represents the gray of the point, and th is a settable threshold value in the range of 100 and 255;

2）：extracting the boundary of the daily ceramic region R to be detected, wherein the method for extracting the boundary is completed through morphological operation,

3): the obtained daily ceramic boundary beta (R) is calculated to have the pixel coordinate of the leftmost upper point as P_LT= ({ (x, y) | (x, y) ∈ β (R), min (y + α x) }, whose rightmost upper point pixel coordinate is, P_RT= { (x, y) | (x, y) ∈ β (R), min (y- α x) }, where min is a minimum function, α is a settable coefficient, and is between 0.2 and 1;

the step of the coordinate conversion process in the step two is as follows:

1): a first plane pulse coordinate system is formed by the first feeding device (8) and the third feeding device (10),

the horizontal coordinate of the origin of the first plane pulse coordinate system is the position of the first horizontal limit switch (812), the vertical coordinate of the origin is the position of the first vertical limit switch (1012), the horizontal direction is defined as the right direction, and the vertical direction is defined as the upward direction; forming a second plane pulse coordinate system through the second feeding device (9) and the fourth feeding device (11), wherein the horizontal coordinate of the origin of the second plane pulse coordinate system is the position of the second horizontal limit switch (912), the vertical coordinate of the origin is the position of the second vertical limit switch (1112), and the horizontal direction is the left positive direction and the vertical direction is the down positive direction; calibrating pixels and pulses on the plane pulse coordinate system I and the plane pulse coordinate system II to obtain a transformation equation taking the pulses as dependent variables and the pixels as independent variables;

2): according to a transformation equation, the leftmost upper point P in the daily ceramic boundary beta (R)_LTAnd the upper rightmost point P_RTSubstituting the equation to respectively form a pulse coordinate where a stepping motor III (1001) of a feeding device III (10) runs and a pulse coordinate where a stepping motor II (901) of a feeding device II (9) runs;

1): a step motor III (1001) of the driving feeding device III (10) drives a moving block III (1004) to run in a negative direction until the position of a vertical limit switch I (1012) is reached;

2): a first stepping motor (801) for driving the first feeding device (8) drives a first moving block (804) to run in the negative direction until a first horizontal limit switch (812) is located;

3): a second stepping motor (901) of the second driving feeding device (9) drives a second moving block (904) to run in a negative direction until the second horizontal limit switch (912) is located;

4): a step motor IV (1101) of the driving feeding device IV (11) drives a moving block IV (1104) to run in the negative direction until the position of a vertical limit switch II (1112) is reached;

the step of moving the detecting component of the measuring device to the designated position in the third step is as follows:

1): a step motor III (1001) of the driving feeding device III (10) drives a motion block III (1004) to run to reach the pulse coordinates calculated by the transformation equation;

2): a step motor I (801) for driving a feeding device I (8) enables the outer aperture cylinder (13) to abut against the edge of the domestic ceramic port to be measured until the displacement of the outer aperture displacement sensor (12) reaches a position half of the measuring range;

3): a second stepping motor (901) of the second driving feeding device (9) drives a second motion block (904) to run to reach the pulse coordinate calculated by the transformation equation;

4): and driving a stepping motor IV (1101) of the feeding device IV (11) to enable the port edge cylinder (17) to abut against the domestic ceramic port edge to be measured until the displacement of the port edge displacement sensor (16) reaches a position half the measuring range.

4. A measuring method according to claim 3, characterized in that: the calibration steps between the pixels and the pulses are as follows:

1) the planar pulse coordinate system is defined as one or two planesDividing the pulse coordinate system II into N equal parts in the horizontal direction and the vertical direction according to the pulse number in the stroke, wherein N is 2-10, so that N is formed²A marking point is arranged at the position of the outer caliber connecting piece (5) or the opening edge connecting piece (7) of each point to be marked, and the marking point can be marked by a special color pen;

2): the first stepping motor (801) and the third stepping motor (1001) return to a first stepping zero position, and the second stepping motor (901) and the fourth stepping motor (1101) return to a second stepping zero position;

3): the controller component (3) drives the first stepping motor (801), the third stepping motor (1001), the second stepping motor (901) and the fourth stepping motor (1101) to run to a point needing to be calibrated, the camera (6) takes a picture, obtains and records a pixel coordinate corresponding to the marking point, and records the running pulse number of the current stepping motor;

5. A measuring method according to claim 3, characterized in that: the data acquisition and processing steps of the external diameter of the domestic ceramic to be detected are as follows:

1): according to the horizontal distance between the initial position of the right edge of the outer caliber cylinder (13) connected with the outer caliber displacement sensor (12) and the center of the rotary table (201) and the pulse number of the stepping motor I (801) of the feeding device I (8) running to the measuring position, calculating the current center of the rotary table (201)The distance from the right edge of the outer aperture cylinder (13) is used as the initial diameter r₀；

2): the displacement data measured by the outer caliber displacement sensor (12) is represented by an array kdata [ N ], wherein N represents the number of data, the angular speed of the turntable (201) is represented by omega, the data acquisition period measured by the outer caliber displacement sensor (12) is represented by T, and the coordinate of the nth (N belongs to [0, N)) point of the excircle outline of the domestic ceramic to be measured is as follows by taking the center of the turntable (201) as the origin of coordinates: ((kdata [ N ] + r0) cosn ω T, (kdata [ N ] + r0) sinn ω T), thereby obtaining a domestic ceramic excircle contour coordinate point set PS with a set size N;

1) in the process that a turntable (201) of a measuring device carrying part rotates for one circle, the port edge displacement sensor (16) generates corresponding displacement, the port edge displacement sensor (16) outputs voltage quantity which is in linear relation with the displacement, a controller part (3) of the measuring device collects voltage data output by the port edge displacement sensor (16) at regular time, and the timing period is 0.1-10 ms;

the variance is calculated by the formula:

wherein x is_iRepresenting the ith data collected;

3) in the remaining data, the maximum and minimum values are found, and the absolute value of the difference is used as the final result of the height difference of the lip.