CN115042015A

CN115042015A - Measuring head on-machine measuring method for key characteristic parameters of complex parts

Info

Publication number: CN115042015A
Application number: CN202210385978.9A
Authority: CN
Inventors: 张星; 马昂扬; 胡玉玲; 赵万华
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2022-04-13
Filing date: 2022-04-13
Publication date: 2022-09-13
Anticipated expiration: 2042-04-13
Also published as: CN115042015B

Abstract

A measuring head on-machine measuring method for key characteristic parameters of a complex part comprises the steps of firstly determining a single measuring point contact path plan, planning a measuring path in a single characteristic, then planning a measuring path among a plurality of characteristics, and connecting an optimal overall measuring path; measuring by a measuring program to obtain actual measuring point coordinate values of the mark points, and calculating key characteristic parameters; developing a measuring point marking, measuring track generation, measuring program generation and characteristic parameter calculation functional module based on a CAD kernel through CATIA CAA secondary development to form an on-machine measuring system; in the measurement planning stage, firstly, measuring point marking is carried out on a software platform, a measurement track is generated, a measurement program is exported, then, actual measurement is carried out on a machine tool, a measurement result is imported into an on-machine measurement system, and characteristic parameters are calculated and displayed. The invention realizes the quick measurement of the measuring head of the size parameter and the error parameter of the key characteristic of the complex part on machine, has better operability and applicability and is convenient to be applied in the processing field of enterprises.

Description

Measuring head on-machine measuring method for key characteristic parameters of complex parts

Technical Field

The invention belongs to the technical field of machining-measuring integration, and particularly relates to an on-machine measuring method for a measuring head of key characteristic parameters of a complex part.

Background

With the rapid development of the manufacturing industry, the requirement for less or even no human intervention in the cutting process is higher and higher. When parts with high precision requirements are machined, on-machine detection is needed between finish machining processes and after the processes, whether the machining process is out of tolerance or over cutting or not is judged, the process quality is guaranteed, but the part of the machining process occupies the starting time of a machine tool, and the machining efficiency is reduced. Therefore, the important challenges of the manufacturing industry in China at present are to reduce manual intervention and improve the automation degree of the processing process, thereby improving the processing quality, improving the inspection level and accelerating the production efficiency.

At present, the quality detection of workpieces is mainly carried out by three methods: the first is manual measurement, the method is that a worker uses a caliper and a dial indicator to perform manual measurement, the measurement process is fast, but the measurement precision is low, the machine tool needs to be stopped, the machine tool starting time is occupied, and only some simple part characteristics can be measured; the second method is measurement by a three-coordinate measuring machine, the method has high precision, does not occupy the starting time of a machine tool, but needs to repeatedly disassemble workpieces, consumes more time and can cause clamping errors and clamping deformation; the third is that the measuring head measures on the machine, this method utilizes the movement system of the lathe oneself to replace the movement axis of the three-coordinate measuring machine, theoretically measure on the machine is the measurement requirement that can be competent in complicated work piece completely, it has saved the work piece and clamped many times too, will improve a lot in the measuring efficiency too.

At present, from the application abroad, a scholars introduces an on-machine measurement system into a machining center of the scholars, the machining time consumption is greatly shortened, and the measurement accuracy can be ensured. The development of domestic on-machine measurement technology is generally laggard, the application is narrower, some machine tools are provided with measuring heads, but the measuring heads are only used for tool setting and are not used for measuring part characteristics when in use; in addition, the measuring head is usually moved in a hand-operated hand wheel mode when in use, only the sensing function of the measuring head is utilized, and the automation degree is very low. Therefore, it is very urgent to develop a practical on-machine measurement system, especially the automatic generation and feature parameter calculation of the complicated part measurement program.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide an on-machine measuring method for the measuring head of the key characteristic parameters of the complex part, which can realize the on-machine rapid measurement of the measuring head of the size parameters and the error parameters of the key characteristics of the complex part, has better operability and applicability and is convenient to apply in an enterprise processing field.

In order to achieve the purpose, the invention adopts the technical scheme that:

a measuring head on-machine measuring method for key characteristic parameters of a complex part comprises the following steps:

step 1) aiming at different areas and multiple features of a complex part, firstly determining a single measuring point contact path plan, then planning a measuring path in a single feature, then planning a measuring path among multiple features, and finally connecting an optimal overall measuring path;

step 2) measuring by a measuring program to obtain actual measuring point coordinate values of the mark points, and further calculating key characteristic parameters, wherein the key characteristic parameters comprise characteristic parameters and error parameters; the characteristic parameters comprise hole characteristic parameters such as hole diameter and hole distance, thin-wall characteristic parameters such as wall height and wall thickness and web thickness characteristic parameters; the error parameters comprise a size error, a hole coaxiality error, a hole perpendicularity error, a surface planeness error and a surface profile error;

step 3) a module of the CATIA is developed through the CATIA CATA for the second time, and functional modules such as measuring point marking, measuring track generation, measuring simulation, measuring program generation, data reading, error calculation, characteristic parameter calculation and the like are developed by means of a CAD kernel of the CATIA to form an on-machine measuring system;

step 4) in the measurement planning stage, firstly, marking measurement points on a software platform, then generating a measurement track, and exporting a measurement program; then, actual measurement is performed on the machine tool; and finally, importing the measurement result into an on-machine measurement system, and calculating and displaying the characteristic parameters.

The specific process of the step 1) is as follows:

1.1) planning of single measuring point contact path:

the speed of the measuring head is reduced before the measuring head contacts the measuring point, the measuring head returns to the point after being triggered and then the speed is increased, and the point is the speed changing point;

the point of the measuring head contacting the workpiece is a contact point, the contact point is a position marked on the CAD model, a deviation point is defined at the lag position of the marked measuring point, and the point is used as the measuring point to be contacted by the actual measuring head;

when a measuring program is written, the coordinates of the offset point are taken as measuring points, and finally, the contact path of a single measuring point is at the starting point p _s Decelerating, opening the trigger switch of the measuring head, feeding the measuring head along the normal direction of the measuring point and at the actual contact point p _c Stopping, and then accelerating to return to a starting point;

1.2) planning paths among characteristic internal measuring points:

the path among the single characteristic internal measuring points needs to be planned according to the specific distribution of the measuring points, interference is not considered when the characteristic internal measuring points move, and only the difference of the number of the measuring points is realized, so that the path in the characteristic is fixed after being determined, and the path with the same characteristic is directly applied when being planned each time without re-planning; planning each feature by using the minimum measuring point number, and copying a path according to the number of the measuring points;

1.2.1) aperture measurement path planning:

when the aperture of the single hole characteristic is measured, measuring points are required to be on the same plane, and the aperture can be measured by at least 3 measuring points; after the path of a single measuring point is fixed, only one inlet needs to be selected from the measuring points, namely the position of the measuring head entering the aperture from the safety plane, then the other measuring points are measured in sequence, the starting position of the last measuring point is defined as an outlet, and the measuring head exits from the outlet position to the safety plane;

1.2.2) pitch measurement path planning:

the measurement of the pitch of holes needs to obtain the coordinates of the centers of circles of two holes, if the center of a circle of each hole is to be determined, each hole needs at least 3 measuring points, so that the pitch of holes is divided into the diameters of the two holes for planning a path when being measured, the path is withdrawn to the track of a safety plane after one hole is measured, and the hole sections of the two holes are ensured to be the same plane when the pitch of holes is measured;

1.2.3) hole verticality measurement path planning:

the axis of the hole needs to be measured when the hole verticality is measured, so that at least two cross sections in the hole are selected, the circle centers of the two cross sections are measured, and the axis is obtained, so that the two cross sections plan a path according to the hole diameter measurement, and each cross section has at least 3 points; in addition, a base plane needs to be measured, at least 3 points are needed to determine a plane according to a plane equation, and the dispersion of measuring points is guaranteed as much as possible when the points are taken;

1.2.4) thin wall thickness and wall height measurement path planning:

obtaining a plane by adopting least square, and calculating the thickness or height by using the average value of the distances from a plurality of measuring points on the other plane to the plane, so that at least 3 measuring points are selected on the plane, and 3 points on the reference plane are dispersed as much as possible;

1.2.5) web thickness measurement path planning:

when the thickness of the web plate is measured, two planar measuring paths are separated, and each path is an independent planar measuring path;

1.2.6) surface measurement path planning:

measuring points need to be marked along the direction of the curved surface in the curved surface profile measurement, the number of the marked measuring points depends on the size of the curved surface, and at least two sections need to be marked;

1.3) planning the inter-feature path:

the inter-feature path is regarded as path planning in a two-dimensional plane, each feature in the two-dimensional plane is regarded as a feature point, and the path planning in the features has no interference, so that the planning basis is to find the shortest measuring path among the features, the planning of the inter-feature path is converted into a TSP problem, and the shortest path is expressed as follows:

in the formula: t is time; i, j and s are points on the path;

pheromones on paths of a point i and a point j at the time t;

heuristic factors of a point i and a point j at the time t; α is the relative degree of importance of τ; beta is the relative significance of eta; allowed _k A point set which can be selected by the ant k at the time t;

analyzing the distribution characteristics of all the characteristics contained in the workpiece in the space, marking all the characteristics to be measured by using a circle, and projecting the marks onto a plane, wherein the plane is a characteristic point which a measuring head needs to pass on a safety plane; using an ant colony algorithm to optimize the marked feature points to obtain the shortest path among the features;

1.4) overall measurement path planning:

and connecting paths in a plurality of single features in series by using the inter-feature paths to obtain an overall measurement path.

The specific process of the step 2) is as follows:

2.1) calculation of the pore characteristic parameters:

(1) and (3) calculating the aperture:

the aperture is calculated from the average of the distances from all the measuring points to the center of the circle, and is shown as the following formula:

in the formula: n is the number of the measuring points; (x) _i ,y _i ) Is the coordinate of the ith measuring point; (x) ₀ ,y ₀ ) Is a hollow center coordinate;

(2) calculating the pitch of holes:

on the basis of aperture calculation, the distance between the centers of the cross sections of the two holes is calculated, and the cross sections of the two holes are in the same plane; suppose that the coordinates of the two circle centers are respectively (x) ₀₁ ,y ₀₁ ,z ₀₁ )，(x ₀₂ ,y ₀₂ ,z ₀₂ ) Calculating the distance between the two circle centers according to a distance formula;

2.2) calculation of thin-wall characteristic parameters:

the method for calculating the wall height and the wall thickness in the thin-wall feature needs to be measured, firstly, an equation of one surface is determined through coordinates, then, the distance from a point on a second surface to a first surface is calculated through the distance from the point to the surface, and the average value of the obtained multipoint distances is the parameter of the wall height and the wall thickness of the thin-wall feature, and is shown in the following formula;

in the formula: (x) _i ,y _i ,z _i ) Coordinates of the ith measuring point are shown; n is the number of the measuring points; (a, b, c, d) are coefficients of a first plane equation ax + by + cz + d ═ 0;

2.3) calculating the characteristic parameters of the web:

when the web thickness is measured, coordinate transformation needs to be carried out on the measuring points respectively after the measurement of the two stations is completed, the measuring points are converted to be below a workpiece coordinate system, and the web thickness calculation formula is obtained by referring to a thin-wall calculation method after the conversion is completed as follows:

in the formula: d _j The thickness parameter of the ith measuring point is shown in the formula (4); n is a radical of _j The number of the measuring points is;

2.4) calculation of the dimensional error of the characteristic thickness:

after obtaining the dimension thickness measurement value of the part feature, obtaining the dimension error by subtracting the dimension thickness measurement value from the design value, as shown in the following formula;

e _l ＝l _m -l ₀ (6)

in the formula: l _m Is a measured value; l ₀ Is a design value;

2.5) calculation of hole coaxiality error parameters:

in different cross-sections of the holeMeasuring the aperture to obtain N _k Center coordinates (x) of each cross-sectional circle _c,k ,x _c,k ,x _c,k ) Calculating the axis z of the hole as c according to the centers of the plurality of section circles _a x+c _a y+c _a Then calculating the distance d from the center of each section circle to the straight line _c,k Finally, calculating the average value of the coaxiality error, wherein the calculation formula is as follows;

2.6) calculating the hole perpendicularity error parameter:

according to the definition of perpendicularity, the reference surface equation is set as

Measurement point P _i (x _i ,y _i ,z _i ) The average deviation of the reference section along the normal direction is the hole verticality error, and the calculation formula is as follows;

in the formula: n is a radical of _i Counting the number of the measuring points; i is a measuring point number; (x) _i ,y _i ,z _i ) Coordinates of the ith measuring point are shown; (v) _a ,v _b ,v _c ) Is the coefficient of the reference plane equation;

2.7) calculation of the error of the surface flatness:

obtaining coordinates P of a point on the actual workpiece plane by measurement _i (x _i ,y _i ,z _i ) By least squares, to obtain N _i The plane equation of each measuring point is z ═ p _a x+p _b y+p _c And then calculating the minimum variance between the actual workpiece plane and the measuring points as follows:

in the formula: (p) _a ,p _b ,p _c ) The coefficients of the measuring point plane equation are obtained;

2.8) calculation of face profile error:

obtaining coordinates P of a point on the actual workpiece plane by measurement _i (x _i ,y _i ,z _i ) And calculating the distance d between the design surface and the design surface _i And then calculating the profile error of the surface by the following formula:

the specific process of the step 3) is as follows:

3.1) measuring point marking and path generation are carried out in the measuring planning stage, then actual measuring head measurement is carried out on a machine tool, and finally, measuring data are imported into measuring system software for calculating and displaying key characteristic parameters;

3.2) measuring point marking module:

the measuring point marking module is nested in a grading way by using two options of characteristics and parameters, wherein the characteristics are a first grade, and the parameters are a second grade; the method is characterized by comprising the steps of (1) forming holes, thin walls, ribs, columns, lugs and cambered surfaces, wherein parameters to be measured are different in each characteristic, and when measuring points are marked, the characteristics are selected individually, but the parameters can be selected more, so that the final effect is that the characteristics comprise the parameters to be measured; different measurement parameters have different measuring point numbers, so that the number of measuring points required by different parameter combinations and the position sequence of the marked measuring points need to be analyzed independently, and a prompt needs to be given when the measuring points are marked each time; in the aspect of operation logic, after a feature is selected, parameters which can be measured by the feature are in an enabled state, the rest are in a disabled state, then a mark measuring point button is in an enabled state, an adding button is in a disabled state, after the mark measuring point button is clicked, the number of measuring points of the mark is prompted to be given, the mark measuring point button is placed in the disabled state, the adding button normally operates after the mark is completed, but the mark measuring point button cannot be clicked, only the measuring points of the mark are added into a measuring point list, the next group of operation can be carried out, and the marked feature, the matched parameters and the number information of the mark can be given by a right list frame;

3.3) a measuring track generating module:

the measuring track generating module is divided into two parts, the path in the feature is fixed, after the measuring point marking part is finished, the path in the feature is generated, the key point of the measuring track generating module is the path between the designated cutter lifting position and the generated feature, the normal vector information in the graph is used for displaying the normal vector information of the measuring point relative to the surface in the CAD model, the safety plane button is the designated cutter lifting height, the measuring track button is used for generating the final measuring track, and the generated track is displayed in the CAD model; in the track generation, a starting point and an offset point can be automatically generated, the starting point can be displayed in the CAD model, the starting point is also a variable speed point in the measurement, and the offset point is not displayed in the CAD model but is seen through a list box on the right side of a window;

3.4) a measurement simulation module:

the measurement simulation module simulates a measurement process in a CAD (computer-aided design) model, the measuring head is also a Part type digital analog in the CATIA (computer-aided three-dimensional interactive application), the measuring head can pause and stop at any time in the simulation process, and if the measuring head collides with a workpiece in the movement process, the simulation can automatically stop; judging interference by using volume collision in the CATIA, and directly recording coordinates at the interference position and displaying the coordinates on a window;

3.5) a measurement program generation module:

the measuring program generating module firstly considers the setting of the allowance, and sets the corresponding allowance for each procedure to generate the actual position of the measuring point in different procedures aiming at the measurement among the procedures; the principle is that the measuring point moves along the normal vector direction relative to the plane where the measuring point is located, and the moving distance depends on the margin set in the process; the second key parameter is the setting of the coordinate system, the set coordinate system is the measurement coordinate system, the measuring point position in the measuring program can be subjected to coordinate transformation according to the set coordinate system, and the generated measuring program is the program for transforming the coordinates; the program head and the program tail in the window are set with default values and are changed by a technologist, the technologist adjusts the position of the measuring program by the program tail, and the program head is used for setting information such as measuring head replacement, measuring speed and the like; the generated measuring program is displayed on the right side of the window, and the file is stored to the local in a txt file type;

3.6) a data reading module:

the data reading module is used for reading the actually measured coordinate information into the measuring system, the types of the read files are xls and xlsx, the measured points are displayed in the CAD model by the measured point display button, and the coordinate information of the actually measured points is displayed on the right side of the interface;

3.7) an error calculation module:

the error calculation module is used for calculating the deviation between the measured point and the ideal measuring point, specifically the distance between the measured point and the plane to which the measured point belongs, judging whether the deviation is out of tolerance or not according to the distance, displaying the error result in a right list frame of a window, and marking the error in the CAD model; if an upper error limit is established, judging where the out-of-tolerance exists according to the error size;

3.8) a characteristic parameter calculation module:

the characteristic parameter calculating module is used for calculating the size to be measured, the value of the characteristic parameter to be calculated is preset in the characteristic marking module, the algorithm is translated into a code and written into a background according to the characteristic calculating method, the input value is an actually measured coordinate point, and the output is a characteristic parameter value at the calculating position.

The specific process of the step 4) is as follows:

4.1) marking measuring points on a workpiece digital model:

when the software is used for marking, measuring point marking operation is carried out under the Product environment of CATIA, and the software indexes the workpiece from the Product level; the information of a measuring head needs to be acquired in advance at a marking measuring point, a measuring distance and an offset distance need to be set in advance, and information of a single characteristic parameter measuring point, an offset point related to the single characteristic parameter measuring point and a start measuring point is generated in real time when the measuring point is marked; when marking measuring points, firstly selecting the characteristics to be marked, then selecting parameters for characteristic measurement, and then clicking a button for marking the measuring points, namely marking the measuring points on the model, wherein the characteristics outside the holes are marked on the surface, and the number of the measuring points is required to be set for manual point selection;

4.2) generating a measuring track:

generating a measuring track to directly generate the whole measuring track, wherein the measuring track inside a single feature and among a plurality of features can be directly displayed on a digital-analog through a straight line and an arrow after background program calculation is finished; an important step in measuring the track is to set the cutter lifting height, and the cutter lifting height is finished by selecting a safety plane distance which is set in advance;

4.3) generating a measuring program:

the measurement program needs to be provided with allowance, different processes and different allowances, and the measurement program for generating a plurality of processes is provided; in addition, a measurement coordinate system needs to be arranged, and the measurement coordinate system and the processing coordinate system are consistent; the transfer speed and the measurement speed are customized, the transfer speed is accelerated, the measurement time is shortened, the measurement speed is reduced, and the measurement precision is improved; the file name of the measuring point is used for automatically acquiring the file name set by the coordinate of the measuring point in numerical control, the program head and the program tail are customized and modified, and the measuring program is generated by clicking to obtain a txt file;

4.4) measuring the machine tool measuring head on the machine:

when actual measurement is carried out on a machine tool, firstly, a measurement program is opened on a numerical control system interface, and if the measurement is carried out in the working procedure, the measurement program is directly operated; after the measurement is finished, generating a subprogram file with a measuring point coordinate, wherein the file contains all measuring point coordinates and is used for directly checking or subsequently calculating characteristic parameters;

4.5) post-processing to calculate characteristic parameters and error parameters:

and importing the obtained coordinate file into software, calculating characteristic parameters and error parameters in an error analysis module, and displaying the calculated result on a digital-analog window.

The invention has the beneficial effects that:

(1) the invention provides an on-machine measuring method for a measuring head of key characteristic parameters of a complex part, which has better applicability and can realize on-machine automatic measurement of the characteristics of the complex part.

(2) The invention has the functions of measuring point marking, measuring track generation, measuring program generation, characteristic parameter calculation, measuring process motion simulation, interference check, data display and the like, and can systematically solve the difficult problem of measuring the measuring head on machine.

(3) The invention can realize the measurement, calculation and display of various characteristic parameters and error parameters of the complex parts, wherein the characteristic parameters comprise hole characteristic parameters such as aperture, hole distance and the like, thin-wall characteristic parameters such as wall height, wall thickness and the like, and web thickness characteristic parameters, and the error parameters comprise size error, hole coaxiality error, hole perpendicularity error, surface flatness error and surface profile degree.

(4) When the measuring path is generated, the single characteristic internal track and the tracks among the plurality of characteristics are generated step by step, the whole measuring path is optimized, the global shortest path can be finally obtained, and the measuring efficiency is improved.

(5) The invention has better compatibility with the existing commercial cata software, can realize the import of any complicated part digifax, the export of the measuring program and the import of the actual measuring data of the machine tool, can be deployed on a computer of a technologist, has the advantages of flow and standardization of operation, and is convenient for application in enterprises.

Drawings

FIG. 1 shows a single point contact path plan.

Fig. 2 is a flow of measurement path planning within a single feature.

Fig. 3 is an aperture measurement path.

Fig. 4 shows a pitch measurement path.

FIG. 5 is a hole perpendicularity measurement path.

FIG. 6 is a thin wall thickness and wall height measurement path, wherein (a) is a wall thickness measurement path; (b) the wall height measurement path.

Fig. 7 is a web thickness measurement path.

FIG. 8 is a curved profile measurement path.

FIG. 9 is a schematic view of an inter-feature path layout, wherein (a) is a plurality of measured feature points on a workpiece; (b) and optimizing the shortest measurement path for the ant colony algorithm.

FIG. 10 is an overall measurement path on a part.

Fig. 11 is a functional architecture of the on-machine measuring system of the measuring head.

FIG. 12 is a station marking module wherein (a) is a assay marking module software interface; (b) and marking effect for the measuring points.

FIG. 13 is a measurement trace generation module, wherein (a) is a measurement trace generation module software interface; (b) an effect is generated for the measured trajectory.

FIG. 14 is a measurement simulation module wherein (a) is a measurement simulation module software interface; (b) to measure the simulation effect.

FIG. 15 is a measurement program generation module software interface.

FIG. 16 is a data read module wherein (a) is a data read module software interface; (b) the display effect is read in for the data.

FIG. 17 is an error calculation module, (a) an error calculation module software interface; (b) and calculating an error to display the effect.

FIG. 18 is a feature parameter calculation module software interface.

Detailed Description

The invention is described in detail below with reference to the figures and examples.

A measuring head on-machine measuring method for key characteristic parameters of complex parts comprises the following steps:

1.1) planning of single measuring point contact path:

when the measuring head contacts with a workpiece, the speed is too high, the collision is possible, the measuring head is damaged, and when the measuring head moves among measuring points, the higher speed is needed to ensure the measuring efficiency, so that the speed is reduced before the measuring head contacts with the measuring points, the measuring head returns to the point after being triggered, and the speed is increased, and the point is a speed changing point;

the point of the measuring head contacting the workpiece is a contact point, the contact point is a position marked on the CAD model, however, the position on the workpiece in actual processing may be advanced or lagged, the measuring head automatically returns and records the coordinates of the measuring ball center point of the starting position only after being triggered, therefore, in order to ensure that the measuring head can be triggered, an offset point is defined at the lagging position of the marked measuring point, and the point is used as the measuring point to be contacted by the actual measuring head;

as shown in FIG. 1, when the measurement program is written, the coordinates of the offset point are used as the measurement point, and finally, the contact path of a single measurement point is at the starting point p _s Decelerating, opening the trigger switch of the measuring head, feeding the measuring head along the normal direction of the measuring point and at the actual contact point p _c Stopping, and then accelerating to return to a starting point;

1.2) planning the path among the characteristic measuring points:

the path among the single characteristic internal measuring points needs to be planned according to the specific distribution of the measuring points, interference is not considered when the characteristic internal measuring points move, and only the difference of the number of the measuring points is realized, so that the path in the characteristic is fixed after being determined, and the path with the same characteristic is directly applied when being planned each time without re-planning; when planning each feature, firstly planning by using the minimum measurement point number, and then copying the path according to the number of the measurement points, therefore, the planning flow of the measurement path in a single feature can be represented as shown in fig. 2;

1.2.1) aperture measurement path planning:

when the aperture of the single hole characteristic is measured, measuring points are required to be on the same plane, and the aperture can be measured by at least 3 measuring points; after the path of a single measuring point is fixed, only one inlet needs to be selected from the measuring points, namely the position of the measuring head entering the aperture from the safety plane, then the other measuring points are measured in sequence, the starting position of the last measuring point is defined as an outlet, and the measuring head exits from the outlet position to the safety plane, as shown in fig. 3;

1.2.2) pitch measurement path planning:

as shown in fig. 4, the hole distance measurement needs to obtain the coordinates of the centers of two holes, and if the center of each hole is to be determined, each hole needs at least 3 measuring points, so that the hole distance measurement is divided into two hole apertures to plan a path, and the path exiting to the safety plane after one hole is measured is seen from the hole distance measurement, and the hole sections of the two holes are ensured to be the same plane when the hole distance is measured;

1.2.3) hole perpendicularity measurement path planning:

the axis of the hole needs to be measured when the hole verticality is measured, so that at least two cross sections in the hole are selected, the circle centers of the two cross sections are measured, and the axis is obtained, so that the two cross sections plan a path according to the hole diameter measurement, and each cross section has at least 3 points; in addition, a base plane needs to be measured, at least 3 points are needed to determine a plane according to a plane equation, the measured points are dispersed as much as possible when the points are taken, and the measurement path of the hole verticality is shown in FIG. 5;

1.2.4) thin wall thickness and wall height measurement path planning:

as shown in fig. 6, the thickness and height of the thin wall are two characteristic parameters to be measured, theoretically, the two parameter measurements only need to calculate the distance between two measuring points along the thickness or height direction, but in consideration of the measurement accuracy, a plane is obtained by using least squares, and the thickness or height is calculated by the average value of the distances from a plurality of measuring points on the other plane to the plane, therefore, at least 3 measuring points are selected on the plane, and 3 points on the reference plane are dispersed as much as possible, especially when measuring the height;

1.2.5) web thickness measurement path planning:

when the thickness of the web is measured, if the path is the same as the path of the thin-wall thickness measurement only from the view point of parameter calculation, but two planes cannot be measured at a time because the two surfaces on the web are not positioned at the same station, the two planes need to be separated, and each path is an independent plane measurement path, as shown in fig. 7;

1.2.6) surface measurement path planning:

measuring points need to be marked along the direction of the curved surface in the curved surface profile measurement, the number of the marked measuring points depends on the size of the curved surface, and at least two sections need to be marked in order to measure more accurate curved surface errors, as shown in fig. 8;

1.3) planning the inter-feature path:

the inter-feature path can be regarded as a path plan in a two-dimensional plane, each feature in the two-dimensional plane can be regarded as a feature point, the path plan in the feature has no interference, the planning basis is to find the shortest measuring path between the features, the plan of the inter-feature path can be converted into a TSP problem, the TSP problem is described by finding the shortest route which can enable a traveler to pass through all cities at one time and return to the starting city, and the shortest route can be expressed as follows:

in the formula: t is time; i, j and s are points on the path;

pheromones on paths of a point i and a point j at the time t;

heuristic factors of a point i and a point j at the time t; α is the relative degree of importance of τ; beta is the relative significance of eta; allowed _k A point set which can be selected by the ant k at the moment t;

as shown in fig. 9(a), all the features to be measured are marked with circles, and the marks in the drawing are projected onto a plane, that is, a feature point which the probe needs to pass through on the safety plane. Using ant colony algorithm optimization to the marked feature points to obtain the shortest path among the features as shown in fig. 9 (b);

1.4) overall measurement path planning:

connecting paths in a plurality of single characteristics in series by using the paths among the characteristics to obtain an integral measuring path; as shown in fig. 10, is the final overall measurement path planned on the CAD model.

Step 2) measuring by a measuring program to obtain actual measuring point coordinate values of the mark points, and further calculating key characteristic parameters, wherein the key characteristic parameters comprise characteristic parameters (hole characteristic parameters such as aperture and hole distance, thin-wall characteristic parameters such as wall height and wall thickness, and web thickness characteristic parameters) and error parameters (dimension errors, hole coaxiality errors, hole perpendicularity errors, surface flatness errors and surface profile errors);

2.1) calculation of the characteristic parameters of the pores:

(1) and (3) calculating the aperture:

the aperture can be calculated from the average of the distances from all the measuring points to the center of the circle, as shown in the following formula:

(2) calculating the pitch of holes:

on the basis of aperture calculation, the distance between the centers of the two cross sections is calculated, and it is to be noted that the two hollow cross sections should be in the same plane; suppose that the coordinates of the two circle centers are respectively (x) ₀₁ ,y ₀₁ ,z ₀₁ )，(x ₀₂ ,y ₀₂ ,z ₀₂ ) The distance between the two circle centers can be obtained according to a distance formula;

2.2) calculation of thin-wall characteristic parameters:

the calculation method of the two parameters is the same, firstly, an equation of one surface is determined through coordinates, then, the distance from a point on the second surface to the first surface is calculated through the distance from the point to the surface, and the average value of the obtained multipoint distances is the parameter of the wall height and the wall thickness of the thin-wall characteristic, and is shown in the following formula;

in the formula: (x) _i ,y _i ,z _i ) Coordinates of the ith measuring point are shown; n is the number of the measuring points; (a, b, c, d) is the coefficient of 0 in the first plane equation ax + by + cz + d;

2.3) calculation of web characteristic parameters:

when the thickness of the web plate is measured, the measurement cannot be carried out when the first station is processed, the measurement can be carried out only after the second station is processed, and the reference of the workpiece under different stations is different, so that the coordinate transformation of the measurement points needs to be carried out respectively after the measurement of the two stations is finished, the measurement points are converted to the lower part of a coordinate system of the workpiece, and the calculation formula of the thickness of the web plate can be obtained by referring to a calculation method of a thin wall after the conversion is finished;

in the formula: d is a radical of _j The thickness parameter of the ith measuring point is shown in the formula (4); n is a radical of _j The number of the measuring points is;

2.4) calculation of the dimensional error of the characteristic thickness:

after the measurement value of the dimension thickness of the part feature is obtained, the difference is made between the measurement value and the design value, and the dimension error can be obtained, which is shown in the following formula;

e _l ＝l _m -l ₀ (6)

in the formula: l. the _m Is a measured value; l ₀ Is a design value;

2.5) calculation of hole coaxiality error parameters:

measuring the aperture at different cross sections of the hole to obtain N _k Center coordinates (x) of each cross-sectional circle _c,k ,x _c,k ,x _c,k ) And calculating the axis z of the hole as c according to the centers of the plurality of section circles _a x+c _a y+c _a Then calculating the distance d from the center of each section circle to the straight line _c,k Finally, calculating the average value of the coaxiality error, wherein the calculation formula is as follows;

2.6) calculating the hole perpendicularity error parameter:

Measurement point P _i (x _i ,y _i ,z _i ) The mean deviation from the normal direction to the reference section is the hole perpendicularity error. The calculation formula is as follows;

in the formula: n is a radical of _i Counting the number of the measuring points; i is a measuring point number; (x) _i ,y _i ,z _i ) Coordinates of the ith measuring point are shown; (v) of _a ,v _b ,v _c ) Is the coefficient of the reference plane equation;

2.7) calculation of the error in the flatness of the surface

Obtaining coordinates P of a point on the actual workpiece plane by measurement _i (x _i ,y _i ,z _i ) By least square method, N can be obtained _i The plane equation of each measuring point is z ═ p _a x+p _b y+p _c And further calculating the minimum variance between the plane and the measuring point as follows:

2.8) calculation of face profile error:

step 3) developing a module of the CATIA through CATIA CAA for the second time, developing functional modules of measuring point marking, measuring track generation, measuring simulation, measuring program generation, data reading, error calculation, characteristic parameter calculation and the like by means of a CAD kernel of the CATIA, and forming an on-machine measuring system;

3.1) the whole functional architecture of the measuring head on-machine measuring system is shown in fig. 11, measuring point marks and path generation are carried out in the measuring planning stage, then actual measuring head measurement is carried out on a machine tool, and finally, measuring data are led into measuring system software for carrying out key characteristic parameter calculation and display;

3.2) measuring point marking module:

the measuring point marking module is nested in a grading way by using two options of characteristics and parameters, the characteristics are a first level, the parameters are a second level, the characteristics are provided with holes, thin walls, ribs, upright columns, lugs and cambered surfaces, the parameters to be measured are different for each characteristic, the characteristics are selected singly when measuring points are marked, but the parameters can be selected more, for example, the hole characteristics can measure the aperture, the hole distance and the coaxiality, and the final effect is that the characteristics comprise the parameters to be measured; different measuring parameters have different measuring point numbers, so that the number of measuring points required by different parameter combinations and the position sequence of marked measuring points need to be analyzed independently, and a prompt needs to be given when the measuring points are marked each time; in the aspect of operation logic, after a feature is selected, parameters which can be measured by the feature are in an enabled state, the rest are in a disabled state, then a mark measuring point button is in an enabled state, an adding button is in a disabled state, after the mark measuring point button is clicked, the number of measuring points of a mark is prompted to be given, the mark measuring point button is placed in the disabled state, the adding button can be normally operated after the mark is finished, but the mark measuring point button cannot be clicked, only the measuring points of the mark at this time are added into a measuring point list, the next group of operation can be carried out, and the marked feature, the matched parameters and the number information of the mark can be given out by a right list box. The measuring point marking module software interface and the measuring point marking effect are respectively shown in fig. 12(a) and (b);

3.3) a measuring track generating module:

the measuring track generation module is divided into two parts, the path in the feature is fixed, after the measuring point marking part is finished, the path in the feature is generated, the key point of the module is to specify the position of a cutter lifting tool and generate the path between the features, the normal vector information in the drawing is used for displaying the normal vector information of the measuring point relative to the surface in the CAD model, the safety plane button is used for specifying the height of the cutter lifting tool, the measuring track button is used for generating the final measuring track, and the generated track is displayed in the CAD model. In the track generation, a start measuring point and an offset point can be automatically generated, the start measuring point can be displayed in a CAD model, the start measuring point is also a speed changing point in the measurement, the offset point is used for preventing the situation that a measuring head cannot touch a workpiece due to over-cutting, the offset point is not displayed in the model, but can be seen in a list box on the right side of a window; the measurement trajectory generation module software interface and the measurement trajectory generation effect are shown in fig. 13(a) and (b), respectively;

3.4) a measurement simulation module:

the measurement simulation module mainly simulates a measurement process in a CAD model, a measuring head is also a Part type digital model in CATIA, and a user can draw the measuring head by himself; in addition, the simulation can be paused and stopped at any time in the simulation process, and if the measuring head collides with the workpiece in the motion process, the simulation can be automatically stopped. The volume collision in the CATIA is utilized to judge the interference, and the coordinate of the interference position is directly recorded and displayed on a window. The software interface of the measurement simulation module and the decibel of the measurement simulation effect are shown in fig. 14(a) and (b);

3.5) measurement program generating Module

The measuring program generating module firstly considers the setting of the allowance, and aiming at the measurement among the processes, the CAD model can not provide a rough machining or semi-fine model, so that the corresponding allowance needs to be set for each process to generate the actual positions of measuring points in different processes; the principle is that the measuring point moves along the normal vector direction relative to the plane where the measuring point is located, and the moving distance depends on the margin set in the process; the second parameter set mainly is the setting of the coordinate system, the set coordinate system is the measurement coordinate system, the measuring point position in the measuring program can be subjected to coordinate transformation according to the set coordinate system, and the generated measuring program is the program for transforming the coordinates. The program head and the program tail in the window have set default values, but can be changed by a technician because the measuring program may be in the process or after the process, so that the technician can adjust the position of the measuring program by the program tail, and the program head can be used for setting information such as probe replacement, measuring speed and the like. The generated measuring program is displayed at the right side of the window, and the file can be saved to the local in a txt file type without error. The measurement program generation module software interface is shown in FIG. 15;

the common basic format and code for the measurement program are annotated as follows:

N10 G54 G90

G01F 3000; % defines initial velocity, linear motion

N20T ═ CE M6; % change cutter is a measuring head and can be customized

DEF INT RESULT; % definition of shaping variables

N30X 123.581Y 79.1502Z 20; % move to safe plane position above first measurement station

N40X 123.581Y 79.1502Z-20; % move to Start Point position of first Point

N50 MEAS ═ 1G 01F 200X 116.56Y 82.9856Z-20; % using MEAS instruction to start measuring head starting command, deleting multiple pre-strokes when MEAS value is 1, and automatically returning to after triggering measuring head

STOPRE; % add to the command, give time to read trigger value

N60R 1 ═ AA _ MW [ X ] R2 ═ AA _ MW [ Y ] R3 ═ AA _ MW [ Z ]; % temporarily stores the data value triggered by the measuring head through an R variable, and AA _ MW [ ] is used for reading the coordinate of the spindle tool point

WRITE (RESULT, "123", < < R < 1 >); % the value of the R variable is written by a WRITE WRITE command into a subroutine file named "123", which is in the same directory as the measurement program file

WRITE(RESULT,"123",<<R[2])

WRITE(RESULT,"123",<<R[3])

N70F 1000X 123.581Y 79.1502Z-20; % measurement ends, return to start point

N80X 130.35Y 56.0811Z-20; % moves to the next station, if in the same feature, then does not need to move to safe plane, otherwise needs to move to safe plane first

N90 MEAS ═ 1G 01F 200X 126.514Y 49.0604Z-20; % begins measurement of the second station

STOPRE

N100R 1 ═ AA _ MW [ X ] R2 ═ AA _ MW [ Y ] R3 ═ AA _ MW [ Z ]; the numerical value in the% R variable can be read to cover, be repeatedly used and reduce the using amount of the R variable

WRITE (RESULT, "123", < < R < 1 >); % repeatedly written variable stored points coordinates

WRITE(RESULT,"123",<<R[2])

WRITE(RESULT,"123",<<R[3])

N110F 1000X 130.35Y 56.0811Z-20; % measurement of the next spot was repeated until the end

N120 X153.419 Y62.8498 Z-20

……

N560X 128.268Y-7Z 20; % last Point complete Return safety plane

M30; % end of measurement

3.6) a data reading module:

the data reading module is used for reading the actually measured coordinate information into the measuring system, the types of the readable files are xls and xlsx, the measured point display button is used for displaying the measured point in the CAD model, and the coordinate information of the actually measured point is displayed on the right side of the interface; the software interface of the data reading module and the data reading display effect are respectively shown in fig. 16(a) and (b);

3.7) an error calculation module:

the error calculation module is used for calculating the deviation between the measured point and the ideal measured point, specifically the distance between the measured point and the plane to which the measured point belongs, whether the deviation is out of tolerance can be judged according to the distance, the error result can be displayed in a right list box of the window, and the error can be marked in the CAD model. If an upper error limit is set in the module, the error can be used for judging where the out-of-tolerance exists; the error calculation module software interface and the error calculation display effect are respectively shown in fig. 17(a) and (b);

3.8) a characteristic parameter calculation module:

the characteristic parameter calculation module is used for calculating the size to be measured, the value of the characteristic parameter to be calculated is preset in the characteristic marking module, the algorithm is translated into a code and written into a background according to the characteristic calculation method mentioned in the previous section, the input value is an actually measured coordinate point, and the output is a characteristic parameter value at the calculation position; the calculated characteristic parameter values are displayed in a window list box, as shown in fig. 18;

step 4) in the measurement planning stage, firstly, marking measurement points on a software platform, then generating a measurement track, and exporting a measurement program; then, actual measurement is performed on the machine tool; finally, the measurement result is imported into an on-machine measurement system for characteristic parameter calculation and display;

4.1) marking the measuring points on the workpiece digital model:

when marking is carried out by using software, attention needs to be paid to the point measurement marking operation under the Product environment of CATIA, and the indexing of workpieces by the software is carried out from the Product level. The marking measuring points need to acquire information of a measuring head in advance, such as the radius of a measuring ball, and need to set a measuring distance and an offset distance in advance, so that information of a single characteristic parameter measuring point, an offset point related to the single characteristic parameter measuring point and a starting point can be generated in time when the measuring points are marked; when marking measuring points, firstly selecting the characteristics to be marked, then selecting the parameters which can be measured by the characteristics, and then clicking a mark measuring point button, marking the measuring points on the model, wherein the characteristics outside the holes are that the points are marked on the surface, and the number of the measuring points is required to be set for manual point selection;

4.2) generating a measuring track:

the whole measuring track can be directly generated by generating the measuring track, and the measuring track inside a single feature and among a plurality of features can be directly displayed on a digital-analog through a straight line and an arrow after background program calculation is finished; an important step in measuring the trajectory is to set the cutter lift height, i.e., the safe plane distance, in order to prevent interference when moving between features. The cutter lifting height can be completed by selecting a safety plane distance which is set in advance;

4.3) generating a measuring program:

allowance needs to be set in the measuring program, because the workpiece is the workpiece after final processing is finished, the working procedures are different, the allowance is also different, and the measuring program capable of generating a plurality of working procedures is set; in addition, a measurement coordinate system needs to be arranged, and the measurement coordinate system and the processing coordinate system are kept consistent, so that errors caused by different origin points can be avoided; the transfer speed and the measurement speed can be customized, the transfer speed can be accelerated to reduce the measurement time, and the measurement speed needs to be reduced to improve the measurement precision. The file name of the measuring point is the file name for automatically acquiring the coordinate setting of the measuring point in numerical control. The program head and the program tail can be modified in a user-defined mode, and a measuring program is clicked to generate a txt file;

4.4) measuring the machine tool measuring head on the machine:

when actual measurement is carried out on a machine tool, a measurement program is firstly opened on a numerical control system interface, and if measurement is carried out in a working procedure, tool setting is not needed, and the measurement program is directly operated. After the measurement is finished, a subprogram file with a measuring point coordinate is generated. The file contains all the coordinates of the measuring points, and can be used for directly viewing or subsequently calculating characteristic parameters;

Claims

1. A measuring head on-machine measuring method for key characteristic parameters of a complex part is characterized by comprising the following steps:

step 2) measuring by a measuring program to obtain actual measuring point coordinate values of the mark points, and further calculating key characteristic parameters, wherein the key characteristic parameters comprise characteristic parameters and error parameters; the characteristic parameters comprise hole characteristic parameters of the hole diameter and the hole distance, thin-wall characteristic parameters of the wall height and the wall thickness and web thickness characteristic parameters; the error parameters comprise a size error, a hole coaxiality error, a hole perpendicularity error, a surface planeness error and a surface profile error;

step 3) developing a module of the CATIA through CATIA CAA for the second time, developing a function module of measuring point marking, measuring track generation, measuring simulation, measuring program generation, data reading, error calculation and characteristic parameter calculation by means of a CAD kernel of the CATIA, and forming an on-machine measuring system;

step 4) in the measurement planning stage, firstly, measuring point marking is carried out on a software platform, then a measurement track is generated, and a measurement program is exported; then, actual measurement is performed on the machine tool; and finally, importing the measurement result into an on-machine measurement system, and calculating and displaying the characteristic parameters.

2. The method according to claim 1, wherein the specific process of step 1) is as follows:

1.1) planning of single measuring point contact path:

1.2) planning the path among the characteristic measuring points:

the path between the measuring points in the single feature needs to be planned according to the specific distribution of the measuring points, interference is not considered when the measuring points in the feature move, and only the difference of the number of the measuring points is needed, so that the path in the feature is fixed after being determined, and the path with the same feature is directly applied when the path with the same feature is planned each time without re-planning; when planning each feature, planning by using the minimum measurement point number, and copying a path according to the number of the measurement points;

1.2.1) aperture measurement path planning:

1.2.2) pitch measurement path planning:

1.2.3) hole verticality measurement path planning:

1.2.4) thin wall thickness and wall height measurement path planning:

1.2.5) web thickness measurement path planning:

1.2.6) surface measurement path planning:

1.3) planning the inter-feature path:

in the formula: t is time; i, j and s are points on the path;

pheromones on paths of a point i and a point j at the time t;

1.4) overall measurement path planning:

3. The method according to claim 2, wherein the specific process of step 2) is:

2.1) calculation of the characteristic parameters of the pores:

(1) and (3) calculating the aperture:

(2) calculating the pitch of holes:

on the basis of aperture calculation, the distance between the centers of the cross sections of the two holes is calculated, and the cross sections of the two holes are in the same plane; suppose that the coordinates of the two circle centers are respectively (x) ₀₁ ,y ₀₁ ,z ₀₁ )，(x ₀₂ ,y ₀₂ ,z ₀₂ ) Obtaining the distance between the two circle centers according to a distance formula;

2.2) calculation of thin-wall characteristic parameters:

in the formula: (x) _i ,y _i ,z _i ) The coordinates of the ith measuring point are obtained; n is the number of the measuring points; (a, b, c, d) is the coefficient of 0 in the first plane equation ax + by + cz + d;

2.3) calculating the characteristic parameters of the web:

when the web thickness is measured, coordinate transformation needs to be respectively carried out on the measuring points after the two stations are measured, the measuring points are converted to be below a workpiece coordinate system, and the web thickness calculation formula is obtained by referring to a thin-wall calculation method after the conversion is finished as follows:

2.4) calculation of the dimensional error of the characteristic thickness:

e _l ＝l _m -l ₀ (6)

in the formula: l. the _m Is a measured value; l ₀ Is a design value;

2.5) calculation of hole coaxiality error parameters:

measuring the aperture at different cross sections of the hole to obtain N _k Center coordinates (x) of each cross-sectional circle _c,k ,x _c,k ,x _c,k ) And calculating the axis z of the hole as c according to the centers of the plurality of section circles _a x+c _a y+c _a Then, the distance d from the center of each section circle to the straight line is calculated _c,k Finally, calculating the average value of the coaxiality error, wherein the calculation formula is as follows;

2.6) calculating the hole perpendicularity error parameter:

according to the definition of verticality, the reference surface equation is set as z ═ v _a x+v _b y+v _c Measuring point P _i (x _i ,y _i ,z _i ) The average deviation of the reference section along the normal direction is the hole verticality error, and the calculation formula is as follows;

2.7) calculation of the error of the surface flatness:

2.8) calculation of face profile error:

4. the method according to claim 3, wherein the specific process of step 3) is:

3.2) measuring point marking module:

the measuring point marking module is nested in a grading way by using two options of characteristics and parameters, wherein the characteristics are a first grade, and the parameters are a second grade; the method is characterized by comprising the steps of (1) forming holes, thin walls, ribs, columns, lugs and cambered surfaces, wherein parameters to be measured are different in each characteristic, and when measuring points are marked, the characteristics are selected individually, but the parameters can be selected more, so that the final effect is that the characteristics comprise the parameters to be measured; different measuring parameters have different measuring point numbers, so that the number of measuring points required by different parameter combinations and the position sequence of marked measuring points need to be analyzed independently, and a prompt needs to be given when the measuring points are marked each time; in the aspect of operation logic, after a feature is selected, parameters which can be measured by the feature are in an enabled state, the rest are in a disabled state, then a mark measuring point button is in an enabled state, an adding button is in a disabled state, after the mark measuring point button is clicked, the number of measuring points of the mark is prompted to be given, the mark measuring point button is placed in the disabled state, the adding button normally operates after the mark is completed, but the mark measuring point button cannot be clicked, only the measuring points of the mark are added into a measuring point list, the next group of operation can be carried out, and the marked feature, the matched parameters and the number information of the mark can be given by a right list frame;

3.3) a measuring track generating module:

the measuring track generating module is divided into two parts, the path in the feature is fixed, after the measuring point marking part is finished, the path in the feature is generated, the key point of the measuring track generating module is the position of a specified cutter lifting tool and the path between the generated features, the normal vector information in the graph is used for displaying the normal vector information of the measuring point relative to the surface of the measuring point in the CAD model, the safety plane button is the height of the specified cutter lifting tool, the measuring track button is used for generating the final measuring track, and the generated track is displayed in the CAD model; in the track generation, a starting point and an offset point can be automatically generated, the starting point can be displayed in a CAD model, the starting point is also a speed change point in the measurement, and the offset point is not displayed in the CAD model but can be seen through a list box on the right side of a window;

3.4) a measurement simulation module:

3.5) a measurement program generation module:

3.6) a data reading module:

3.7) an error calculation module:

3.8) a characteristic parameter calculation module:

the characteristic parameter calculating module is used for calculating the size to be measured, the value of the characteristic parameter to be calculated is preset when the characteristic marking module marks the size, the algorithm is translated into a code and written into a background according to the characteristic calculating method, the input value is an actually measured coordinate point, and the output is a characteristic parameter value of a calculating position.

5. The method according to claim 4, wherein the specific process of step 4) is as follows:

4.1) marking measuring points on a workpiece digital model:

when the software is used for marking, measuring point marking operation is carried out under the Product environment of CATIA, and the software indexes the workpiece from the Product level; the information of a measuring head needs to be acquired in advance at a marking measuring point, a measuring distance and an offset distance need to be set in advance, and information of a single characteristic parameter measuring point, an offset point related to the single characteristic parameter measuring point and a start measuring point is generated in real time when the measuring point is marked; when marking the measuring points, firstly selecting the characteristics to be marked, then selecting the parameters for characteristic measurement, and then clicking a button for marking the measuring points, namely marking the measuring points on the model, wherein the characteristics outside the holes are that the points are marked on the surface, and the number of the measuring points is required to be set for manual point selection;

4.2) generating a measuring track:

4.3) generating a measuring program:

the measurement program needs to be provided with allowance, different processes and different allowances, and the measurement program for generating a plurality of processes is provided; in addition, a measurement coordinate system needs to be arranged, and the measurement coordinate system and the processing coordinate system are consistent; the transfer speed and the measurement speed are customized, the transfer speed is accelerated, the measurement time is shortened, the measurement speed is reduced, and the measurement precision is improved; the measuring point file name is used for automatically acquiring the file name set by the coordinate of the measuring point in numerical control, the program head and the program tail are modified in a self-defined mode, and the measuring program is generated by clicking to obtain the txt file;

4.4) measuring the machine tool measuring head on the machine: