TWI438396B - Programming system and method of three-dimensional measuring machine - Google Patents

Description

Three coordinate measuring machine programming system and method

The present invention relates to a programming system and method, and more particularly to a three coordinate measuring machine programming system and method.

Product testing is an important part of the production process. With the development of product manufacturing, product production has changed from high-volume manufacturing to small-volume diversification. Product testing has evolved from sampling inspection to full inspection. Diversified inspection requirements urgently require enterprises to quickly test different products.

The three-coordinate measuring machine is a high-precision, high-efficiency size measuring device. The three-coordinate measuring machine can automatically measure according to a pre-programmed measuring program, and can measure the shape accuracy of parts with complex curved surfaces. The bottleneck that restricts the measurement speed of the three-coordinate measuring machine is the programming speed of the three-coordinate measuring machine. One of the conventional programming methods is to directly program the product using a three-coordinate measuring machine on a user-side computer equipped with a three-coordinate measuring machine. This programming method is slow to program and occupies the machine. Another programming method is to program directly with the 3D design file of the product. This kind of programming method may cause a security accident due to the inconsistency between the 3D design file and the actual object.

In view of the above, it is necessary to provide a three-coordinate measuring machine programming system and method for quickly, safely and reliably programming a three-coordinate measuring machine.

A three-coordinate measuring machine programming system, the system comprising: a point cloud receiving module for receiving point cloud data of a workpiece; and a point cloud processing module for preprocessing and triangulating the point cloud data of the workpiece, Obtaining a triangular mesh model of the workpiece; measuring an element fitting module for fitting different measuring elements according to a triangular mesh model of the workpiece; an element relation computing module for performing a relational operation on the measuring elements, A relational operation element; a coordinate system establishing a module for establishing a workpiece coordinate system according to a triangular mesh model of the workpiece; and a simulation measurement module for generating a measurement path for measuring each measurement element, according to the generated amount The measurement path performs simulation measurement on the workpiece, and the generated measurement path is modified according to the simulation measurement result; and the output module is used to output the measurement element, the relational operation element, the workpiece coordinate system and the measurement path to the three coordinate measurement Machine to generate a measurement program for the workpiece.

A three-coordinate measuring machine programming method, the method comprises the steps of: receiving point cloud data of a workpiece; pre-processing and triangulating the point cloud data of the workpiece to obtain a triangular mesh model of the workpiece; and a triangular mesh model according to the workpiece Fitting different measurement elements; performing relational operations on the measurement elements to obtain relational operation elements; establishing a workpiece coordinate system according to the triangular mesh model of the workpiece; generating a measurement path for measuring each measurement element, according to the generated The measuring path simulates the workpiece, and modifies the generated measuring path according to the simulation measurement result; and outputs the measuring element, the relational operation element, the workpiece coordinate system and the measuring path to the three coordinate measuring machine to generate the workpiece Measurement program.

The invention constructs a triangular mesh model of the workpiece by using the point cloud data of the workpiece, obtains the measurement element information and the relational operation element of the workpiece according to the triangular mesh model of the workpiece, and obtains the measurement required for the automatic measurement by the three coordinate measuring machine. Elements, relational operation elements, workpiece coordinate systems, and measurement paths. And the obtained measurement path is subjected to simulation measurement , to avoid the possibility of collision in the measurement process.

10‧‧‧Three coordinate measuring machine programming system

11‧‧‧Scanner

12‧‧‧ computer

13‧‧‧Three coordinate measuring machine

14‧‧‧Workpiece

200‧‧‧ point cloud receiving module

210‧‧‧ point cloud processing module

220‧‧‧Measurement element fitting module

230‧‧‧Elemental Relational Computing Module

240‧‧‧ coordinate system building module

250‧‧‧Simulation measurement module

260‧‧‧Output module

S301‧‧‧ Point cloud data for receiving workpieces

S302‧‧‧ Point cloud data preprocessing and triangle meshing

S303‧‧‧Fitting measurement elements

S304‧‧‧Measurement element relational operation

S305‧‧‧Create workpiece coordinate system

S306‧‧‧Generation measurement path

S307‧‧‧Is there a collision during the simulation measurement?

S308‧‧‧Modification measurement path

S309‧‧‧ Results output

1 is a schematic diagram of an implementation environment of a three-coordinate measuring machine programming system of the present invention.

2 is a functional block diagram of a three-coordinate measuring machine programming system of the present invention.

3 is a flow chart of a method for programming a three-coordinate measuring machine of the present invention.

Referring to FIG. 1, it is a schematic diagram of an implementation environment of a three-coordinate measuring machine programming system of the present invention.

The implementation environment mainly includes a scanning device 11, a computer 12, and a three-coordinate measuring machine 13. The computer 12 is connected to the scanning device 11 and the three-coordinate measuring machine 13, respectively. The scanning device 11 scans the workpiece 14 to obtain point cloud data for the workpiece 14. The scanning device 11 may be a contact scanner, such as a probe scanner, or may be a non-contact scanner such as an optical lens (CCD) scanner or a three-dimensional laser scanner. In the present embodiment, the point cloud data of the workpiece 14 is quickly acquired using a three-dimensional laser scanner. The three-coordinate measuring machine programming system 10 operates in a computer 12 that establishes a triangular mesh model of the workpiece 14 based on point cloud data of the workpiece 14 received from the scanning device 11, based on the established triangular mesh The model obtains the measurement element information and the relational operation element of the workpiece 14, and the measurement elements, the relational operation elements, the workpiece coordinate system, and the measurement path required for the automatic measurement by the three-coordinate measuring machine 13. The three-coordinate measuring machine 13 measures the same type of workpiece of the workpiece 14 based on the measurement element, the relational operation element, the workpiece coordinate system, and the measurement path.

Referring to Figure 2, it is a functional module diagram of the three-coordinate measuring machine programming system.

The three-coordinate measuring machine programming system 10 includes a point cloud receiving module 200 and a point cloud processing The module 210, the measurement element fitting module 220, the element relationship calculation module 230, the coordinate system establishment module 240, the simulation measurement module 250, and the output module 260.

The point cloud receiving module 200 is configured to receive point cloud data of the workpiece 14 from the scanning device 11.

The point cloud processing module 210 is configured to preprocess and triangulate the point cloud data of the workpiece 14 to obtain a triangular mesh model of the workpiece 14. The pre-processing includes removing overlapping points, noise points, and streamlining point cloud data in the point cloud data. The noise point refers to a point that is larger than the normal position. The streamlining of point cloud data includes curvature filtering, mean filtering, and the like. The purpose of preprocessing is to obtain a point cloud with less data, no distortion, and more uniformity to improve the speed and accuracy of triangular meshing. The triangular meshing is to construct a series of triangles to form a triangular mesh model to approximate the original model. Each triangle is described by its three vertex coordinates and a normal vector. Common methods for triangular meshing include iterative methods and Delaunay algorithms.

The measurement element fitting module 220 is configured to fit different measurement elements according to the triangular mesh model of the workpiece 14 and acquire measurement element information of the workpiece 14 . The measuring elements include lines, faces, circles, balls, cylinders, cones, rings, and the like. In the present embodiment, the measurement element fitting module 220 fits the different measurement elements by the quasi-Newton iteration method according to the least squares principle. The measurement element information is used to describe a corresponding measurement element. For example, the information of the line includes the starting point, the ending point, and the normal of the line; the information of the surface includes the center point of the surface and the normal of the surface; the information of the circle includes the center of the circle, the radius of the circle, and the normal of the circle; The information includes the center point, radius, height of the cylinder and the normal direction of the cylinder; the information of the sphere includes the radius of the sphere and the sphere; the information of the cone includes the radius of the cone and the normal of the cone; the information of the ring includes the ring The normal axis of the long and short axes and the ring.

The element relationship operation module 230 is configured to perform a relational operation on the measurement elements, obtain a relational operation element, and acquire relationship operation element information of the workpiece 14. The relational operations include fitting the measurement elements, calculating intermediate elements of the measurement elements, and calculating intersection elements of the measurement elements. The relational operation elements include points, lines, faces, circles, spheres, cylinders, cones, rings, and the like. For example, fitting a measurement element includes fitting a plurality of circles to a cone, and calculating an intermediate element of the measurement element includes calculating a center line of the two lines, and calculating an intersection element of the measurement element includes calculating two sides. The intersection. In this embodiment, the quasi-Newton iterative method is used to fit the measurement elements according to the least squares principle. Similar to the above-described measurement element information, the relationship operation element information is used to describe the corresponding relational operation element.

The coordinate system establishing module 240 is configured to establish a workpiece coordinate system according to the triangular mesh model of the workpiece 14. The workpiece coordinate system can be established by fitting a face according to the triangular mesh model of the workpiece 14, and rotating the mechanical coordinate system so that the Z coordinate normal of the mechanical coordinate system coincides with the normal direction of the surface, thereby determining the first coordinate axis (ie, determining Base plane; fit a line according to the triangular mesh model of the workpiece 14, rotate the mechanical coordinate system so that the Z coordinate normal of the mechanical coordinate system coincides with the line normal to determine the second coordinate axis; the first rule is the right hand rule The coordinate axis fork is multiplied by the second coordinate axis to obtain a third coordinate axis; a point of the triangular mesh model of the workpiece 14 is measured as the origin of the workpiece coordinate system.

The simulation measurement module 250 is configured to generate a measurement point, a safety surface control point, a proximity distance point, and a rebound distance point of each measurement element, according to the measurement point, the safety surface control point, and the proximity distance of the measurement element. The point and the rebound distance point generate a measurement path. The measurement points of the measurement elements are used to determine corresponding measurement element information. The measurement point, the safety surface control point, the proximity distance point, and the rebound distance point determine the motion path of the three-coordinate measuring machine 13. For example, when the equivalent element is a line, the measurement point includes the start of the line. Point and end point.

The simulation measurement module 250 is further configured to perform simulation measurement on the workpiece 14 according to the generated measurement path. If a collision occurs during the simulation measurement, the triangle in which the collision occurs is marked in the triangular mesh model of the workpiece 14. The measurement path is modified according to the marked collision triangle. The simulation measurement method is as follows: the three-dimensional model of the three-coordinate measuring machine 13 is introduced, and if the three-dimensional model of the three-coordinate measuring machine 13 is not a triangular mesh model, the three-dimensional model of the three-coordinate measuring machine 13 is converted into a triangular mesh model; The generated measurement path moves the triangular mesh model of the three-coordinate measuring machine 13 and/or the triangular mesh model of the workpiece 14, and determines whether the workpiece 14 collides with the three-coordinate measuring machine 13 during the movement, and is in the triangulation of the workpiece 14. The triangle in which the collision occurs is indicated in the grid model.

The method of judging whether the workpiece 14 collides with the three-coordinate measuring machine 13 and marking the collided triangle in the triangular mesh model of the workpiece 14 is as follows: according to the triangular coordinate model of the three-coordinate measuring machine 13 and the workpiece 14, respectively, the three coordinates The various components of the measuring machine 13 and the workpiece 14 construct a bounding box, determining whether the bounding box of the workpiece 14 intersects the bounding box of the various components of the three-coordinate measuring machine 13; if intersected, the surrounding of the intersecting three-coordinate measuring machine 13 The bounding box of the box and the workpiece 14 is divided into sub-bundles of equal size, and the triangle of the triangular mesh model of the workpiece 14 in the triangular mesh model of the workpiece 14 is searched according to the divided sub-bundle, and the minimum distance of the components of the intersecting three-coordinate measuring machine 13 is equal to 0, search The triangle that is reached is the triangle that collided. The three-coordinate measuring machine 13 includes components such as a stylus, an X-axis member, a Y-axis member, and a Z-axis member.

The output module 260 is configured to output the measurement element information and the relational operation element information of the workpiece 14 , and output the measurement element, the relational operation element, the workpiece coordinate system, and the measurement path to the three coordinate measuring machine 13 . The measurement element information and the relational operation element information of the workpiece 14 can be output in a text format, a database format, or a graphic format. Measuring element The element, the relational operation element, the workpiece coordinate system, and the measurement path can be output in the format of the Dimensional Measurement Interface Specification (DMIS).

Referring to Figure 3, it is the main flow chart of the programming method of the three-coordinate measuring machine of the present invention.

In step S301, the point cloud receiving module 200 receives the point cloud data of the workpiece 14 from the scanning device 11.

Step 302: The point cloud processing module 210 performs pre-processing and triangulation on the point cloud data of the workpiece 14 to obtain a triangular mesh model of the workpiece 14. The pre-processing includes removing overlapping points, noise points, and streamlining point cloud data in the point cloud data. The streamlining of point cloud data includes curvature filtering, mean filtering, and the like. The purpose of preprocessing is to obtain a point cloud with less data, no distortion, and more uniformity to improve the speed and accuracy of triangular meshing. The triangular meshing is to construct a series of triangles to form a triangular mesh model to approximate the original model. Each triangle is described by its three vertex coordinates and a normal vector. Common methods for triangular meshing include iterative methods and Delaunay algorithms.

In step S303, the measurement element fitting module 220 fits different measurement elements according to the triangular mesh model of the workpiece 14, and acquires the measurement element information of the workpiece 14. The measuring elements include lines, faces, circles, balls, cylinders, cones, rings, and the like. In the present embodiment, the measurement element fitting module 220 fits the different measurement elements by the quasi-Newton iteration method according to the least squares principle. The measurement element information is used to describe a corresponding measurement element. For example, the information of the line includes the starting point, the ending point, and the normal of the line; the information of the surface includes the center point of the surface and the normal of the surface; the information of the circle includes the center of the circle, the radius of the circle, and the normal of the circle; The information includes the center point, radius, height and normal direction of the cylinder; the information of the ball includes the radius of the sphere and the sphere; the information of the cone includes the size of the cone. The radius and the normal of the cone; the information of the ring includes the length and length of the ring and the normal of the ring.

In step S304, the element relationship operation module 230 performs a relational operation on the measurement elements to obtain a relational operation element, and acquires the relational operation element information of the workpiece 14. The relational operations include fitting the measurement elements, calculating intermediate elements of the measurement elements, and calculating intersection elements of the measurement elements. The relational operation elements include points, lines, faces, circles, spheres, cylinders, cones, rings, and the like. For example, fitting a measurement element includes fitting a plurality of circles to a cone, and calculating an intermediate element of the measurement element includes calculating a center line of the two lines, and calculating an intersection element of the measurement element includes calculating two sides. The intersection. In this embodiment, the quasi-Newton iterative method is used to fit the measurement elements according to the least squares principle. Similar to the above-described measurement element information, the relationship operation element information is used to describe the corresponding relational operation element.

In step S305, the coordinate system establishing module 240 establishes a workpiece coordinate system according to the triangular mesh model of the workpiece 14. The workpiece coordinate system can be established by fitting a face according to the triangular mesh model of the workpiece 14, and rotating the mechanical coordinate system so that the Z coordinate normal of the mechanical coordinate system coincides with the normal direction of the surface, thereby determining the first coordinate axis (ie, determining Base plane; fit a line according to the triangular mesh model of the workpiece 14, rotate the mechanical coordinate system so that the Z coordinate normal of the mechanical coordinate system coincides with the line normal to determine the second coordinate axis, and the first rule according to the right hand rule The coordinate axis fork is multiplied by the second coordinate axis to obtain a third coordinate axis; a point of the triangular mesh model of the workpiece 14 is measured as the origin of the workpiece coordinate system.

Step S306, the simulation measurement module 250 generates a measurement point, a safety surface control point, a proximity distance point, and a rebound distance point of each measurement element, according to the measurement point, the safety surface control point, and the proximity distance point of the measurement element. And the rebound distance point generates a measurement path. The measurement points of the measurement elements are used to determine corresponding measurement element information. The measuring point, The safety surface control point, the approach distance point, and the rebound distance point determine the motion path of the three coordinate measuring machine 13. For example, when the equivalent element is a line, the measurement point includes the start and end points of the line.

In step S307, the simulation measurement module 250 performs simulation measurement on the workpiece 14 according to the generated measurement path. If a collision occurs during the simulation measurement, the triangle in which the collision occurs is indicated in the triangular mesh model of the workpiece 14. Otherwise, if no collision occurs, step S309 is performed. The simulation measurement method is as follows: the three-dimensional model of the three-coordinate measuring machine 13 is introduced, and if the three-dimensional model of the three-coordinate measuring machine 13 is not a triangular mesh model, the three-dimensional model of the three-coordinate measuring machine 13 is converted into a triangular mesh model; The generated measurement path moves the triangular mesh model of the three-coordinate measuring machine 13 and/or the triangular mesh model of the workpiece 14, and determines whether the workpiece 14 collides with the three-coordinate measuring machine 13 during the movement, and is in the triangulation of the workpiece 14. The triangle in which the collision occurs is indicated in the grid model.

The method of judging whether the workpiece 14 collides with the three-coordinate measuring machine 13 and marking the collided triangle in the triangular mesh model of the workpiece 14 is as follows: according to the triangular coordinate model of the three-coordinate measuring machine 13 and the workpiece 14, respectively, the three coordinates The various components of the measuring machine 13 and the workpiece 14 construct a bounding box, determining whether the bounding box of the workpiece 14 intersects the bounding box of the various components of the three-coordinate measuring machine 13; if intersected, the surrounding of the intersecting three-coordinate measuring machine 13 The bounding box of the box and the workpiece 14 is divided into sub-bundles of equal size, and the triangle of the triangular mesh model of the workpiece 14 in the triangular mesh model of the workpiece 14 is searched according to the divided sub-bundle, and the minimum distance of the components of the intersecting three-coordinate measuring machine 13 is equal to 0, search The triangle that is reached is the triangle that collided. The three-coordinate measuring machine 13 includes components such as a stylus, an X-axis member, a Y-axis member, and a Z-axis member.

Step S308, the simulation measurement module 250 modifies the measurement path according to the marked triangle in which the collision occurs, and then returns to step S307 to re-work according to the modified measurement path. Piece 14 performs simulation measurements.

In step S309, the output module 260 outputs the measurement element information and the relational operation element information of the workpiece 14, and outputs the measurement element, the relational operation element, the workpiece coordinate system, and the measurement path to the three-coordinate measuring machine 13. The measurement element information and the relational operation element information of the workpiece 14 can be output in a text format, a database format, or a graphic format. The measurement elements, the relational operation elements, the workpiece coordinate system, and the measurement path can be output in the format of a Dimensional Measurement Interface Specification (DMIS).

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and equivalent modifications or variations made by those skilled in the art in light of the spirit of the present invention are It should be covered by the following patent application.

S301‧‧‧ Point cloud data for receiving workpieces

S302‧‧‧ Point cloud data preprocessing and triangle meshing

S303‧‧‧Fitting measurement elements

S304‧‧‧Measurement element relational operation

S305‧‧‧Create workpiece coordinate system

S306‧‧‧Generation measurement path

S307‧‧‧Is there a collision during the simulation measurement?

S308‧‧‧Modification measurement path

S309‧‧‧ Results output

Claims (10)

A three-coordinate measuring machine programming system, the system comprising: a point cloud receiving module for receiving point cloud data of a workpiece; and a point cloud processing module for preprocessing and triangulating the point cloud data of the workpiece, Obtaining a triangular mesh model of the workpiece; measuring an element fitting module for fitting different measuring elements according to a triangular mesh model of the workpiece; an element relation computing module for performing a relational operation on the measuring elements, a relational operation element; a coordinate system establishing module for establishing a workpiece coordinate system according to a triangular mesh model of the workpiece, the step of establishing the workpiece coordinate system comprising: fitting a surface according to a triangular mesh model of the workpiece, rotating the three coordinate measuring machine The mechanical coordinate system makes the Z coordinate normal of the mechanical coordinate system coincide with the normal direction of the surface to determine the first coordinate axis of the workpiece coordinate system; fit a line according to the triangular mesh model of the workpiece, and rotate the mechanical coordinate system to make the mechanical coordinate system The Z-axis normal coincides with the line normal to determine the second coordinate axis; according to the right-hand rule, the first coordinate axis is multiplied by the second coordinate axis to obtain the third coordinate axis Measuring a point of the triangular mesh model of the workpiece as the origin of the workpiece coordinate system; the simulation measurement module is configured to generate a measurement path for measuring each measurement element, and simulate the workpiece according to the generated measurement path Measuring, and modifying the generated measurement path according to the simulation measurement result; and an output module for outputting the measurement element, the relational operation element, the workpiece coordinate system, and the measurement path to the three-coordinate measuring machine to generate the amount of the workpiece Test program. The three-coordinate measuring machine programming system according to claim 1, wherein the pre-processing comprises removing overlapping points, noise points, and streamlining point cloud data in the point cloud data. The three-coordinate measuring machine programming system according to claim 1, wherein the measuring element fitting module fits different measuring elements by a quasi-Newton iteration method according to a least squares principle. For example, the three-coordinate measuring machine programming system described in claim 1 is characterized in that the simulation measuring module detects the collision by using a bounding box in the process of performing the simulation measurement. The three-coordinate measuring machine programming system of claim 1, wherein the measuring element fitting module is further configured to acquire measurement element information of the workpiece, wherein the element relation computing module is further used for acquiring The relational operation element information of the workpiece, wherein the output module is further configured to output the measurement element information of the workpiece and the relationship operation element information. A three-coordinate measuring machine programming method, the method comprises the steps of: receiving point cloud data of a workpiece; pre-processing and triangulating the point cloud data of the workpiece to obtain a triangular mesh model of the workpiece; and a triangular mesh model according to the workpiece Fitting different measurement elements; performing a relational operation on the measurement elements to obtain a relational operation element; establishing a workpiece coordinate system according to the triangular mesh model of the workpiece, the step of establishing the workpiece coordinate system includes: step according to the triangular mesh model of the workpiece The mechanical coordinate system of the three coordinate measuring machine is combined to make the Z coordinate normal of the mechanical coordinate system coincide with the normal direction of the surface to determine the first coordinate axis of the workpiece coordinate system; fitting a line according to the triangular mesh model of the workpiece Rotating machine coordinate system makes the mechanical coordinate system The Z-axis normal coincides with the line normal to determine the second coordinate axis; according to the right-hand rule, the first coordinate axis is multiplied by the second coordinate axis to obtain the third coordinate axis; a point of the triangular mesh model of the workpiece is measured as a workpiece The origin of the coordinate system; generating a measurement path for measuring each measurement element, performing simulation measurement on the workpiece according to the generated measurement path, and modifying the generated measurement path according to the simulation measurement result; and measuring The elements, the relational operation elements, the workpiece coordinate system, and the measurement path are output to the three-coordinate measuring machine to generate a measurement program for the workpiece. The method for programming a three-coordinate measuring machine as described in claim 6 wherein the pre-processing comprises removing overlapping points, noise points, and streamlining point cloud data in the point cloud data. The method for programming a three coordinate measuring machine according to claim 6, wherein the fitting the different measuring elements according to the triangular mesh model of the workpiece is to fit different quantities according to the principle of least squares by using the quasi-Newton iterative method. Measure the element. The method for programming a three-coordinate measuring machine according to the sixth aspect of the invention, wherein the method of performing simulation measurement on the workpiece according to the generated measuring path utilizes a bounding box to detect the collision. The method for programming a three-coordinate measuring machine according to claim 6, wherein the fitting the different measuring elements according to the triangular mesh model of the workpiece further comprises acquiring the measuring element information of the workpiece, wherein the amount of the measuring The measurement element performs a relational operation, and after obtaining the relational operation element, the method further includes acquiring the relational operation element information of the workpiece, and after acquiring the measurement element information of the workpiece and acquiring the relational operation element information of the workpiece, the measurement element information and the relationship of the output workpiece are further included. Operational element information.