Method for measuring surface roughness of complex curved surface part

Abstract

The application discloses a kind of complex curved surface part surface roughness measurement methods, comprising the following steps: S1, the data model of the part to be measured is imported into five-axis roughness measurement system, and the profile line to be measured is selected on the data model surface of the part to be measured;S2, define accessible area, and analyze the interference situation of the measuring rod on the profile line to be measured, to generate the accessible area of the measuring rod, then according to the accessible area of the measuring rod, the planning path of the measuring rod is generated;S3, the profile line to be measured is divided into a plurality of measurement sequence line segments with the principle that the camber error in the profile line to be measured does not exceed the measuring tip micro movement stroke;S4, the part to be measured is fixed on the measuring equipment, and the measuring rod is controlled to work according to the planning path of the measuring rod, so that the measuring tip moves from the starting point to the end point of the profile line to be measured, the surface roughness measurement of the part to be measured is completed, and the measurement result is output;Compared with the prior art, the best non-interference measurement path can be output, and efficient and high-precision measurement of the surface roughness of the complex curved surface part is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of precision measurement, in particular, to a surface roughness measurement method of a complex curved surface part. BACKGROUND

[0002] The existing surface roughness measurement methods are divided into non-contact measurement and contact measurement. The non-contact measurement is mainly an optical measurement method, but the optical measurement method has high requirements for the part surface state, light incidence conditions, etc. The part surface quality is too poor or the surrounding structure is blocked, which will result in that effective light signals cannot be received and the measurement fails. The contact measurement is to use a small probe to contact and slide on the part surface for measurement. The contact force is small and the adaptability to the environment is strong, but when measuring the surface roughness of a complex curved surface part, the probe is short and cannot rotate, and is affected by the geometry of the part. The sensor may be interfered during measurement, and the accessibility of the measurement is limited.

[0003] At present, although a surface roughness measurement method based on five-axis detection technology appears, which is a new method for solving the surface roughness measurement of a complex curved surface part by combining an inductive surface roughness sensor with a five-axis rotary measuring seat, there are still some deficiencies: 1) When measuring a part with complex structure, the flow channel between the blades is long and curved. If the measurement direction is randomly selected, it is very likely that the probe will interfere with the adjacent blade. Therefore, for a part with complex structure, the geometric characteristics of the part itself form an obstacle to the measured characteristics, and it is impossible to automatically generate a non-interference measurement path to realize the rapid measurement of the surface roughness of the part; 2) According to the definition of surface roughness, the measurement line is defined as a straight line. When measuring the surface roughness of a part with large curvature, although the curved measurement path can be converted into multiple approximate straight line segments for measurement, the measurement efficiency will be greatly reduced, and it is difficult to realize batch measurement of parts with large curvature. SUMMARY

[0004] The present application provides a surface roughness measurement method of a complex curved surface part to solve the technical problem that the existing surface roughness measurement method is difficult to be applied to batch rapid measurement of complex curved surface parts with complex structure and large curvature.

[0005] According to one aspect of the present application, a method for measuring the surface roughness of a complex curved part is provided, comprising the following steps: S1, importing a data model of the part to be measured into a five-axis roughness measurement system, and selecting a profile line to be measured on the surface of the data model of the part to be measured; S2, defining an accessible region, and analyzing the interference of the measuring rod on the profile line to be measured to generate an accessible region of the measuring rod, and then generating a planned path of the measuring rod according to the accessible region of the measuring rod; S3, dividing the profile line to be measured into a plurality of measurement sequence line segments according to the principle that the arch height error in the profile line to be measured does not exceed the micro-motion stroke of the measuring tip; S4, fixing the part to be measured on the measurement device, and controlling the measuring rod to work according to the planned path of the measuring rod, so that the measuring tip moves from the starting point to the ending point of the profile line to be measured, and the surface roughness measurement of the part to be measured is completed, and the measurement result is output.

[0006] Further, in step S3, the specific steps of defining the accessible region are as follows: selecting any measurement point on the profile line to be measured to establish a local coordinate system, taking the surface normal of the measurement point as the Z axis, taking the tangent of the measurement sequence line segment of the measurement point as the X axis, and taking the straight line passing through the measurement point and perpendicular to the Z axis and the X axis as the Y axis; obtaining the angle ω between the projection line of the measuring rod in the X-Y plane and the X axis when the measuring rod axis and the surface normal of the measurement point coincide, and then taking the right-hand coordinate system direction as the positive direction of ω, then the theoretical value range of ω is [-π, π], the theoretical value range of ω is discretized into n intervals, and the accessible region of the measurement point is represented as a 1xn row vector, any element in the row vector takes the value of 0 or 1, wherein 0 represents that the measuring rod interferes with the part to be measured when ω is the angle, and 1 represents that the measuring rod interferes with the part to be measured when ω is the angle; the profile line to be measured is discretely represented as m sampling points, and the accessible region of the measuring rod is represented as an mxn matrix, and each element of the matrix represents whether the current measurement point is accessible in the direction of the measuring rod.

[0007] Further, the specific steps of analyzing the interference of the measuring rod on the profile line to be measured are as follows:

[0008] The direction vectors of the X axis, the Y axis and the Z axis in the local coordinate system in the part coordinate system of the five-axis roughness measurement system are represented as f=[f x ,f y ,f z ] T , k=[k x , k y , k z ] T , n=[n x , n y , n z ] T , and the angle θ between the measuring rod axis and the measuring tip axis is obtained, and the direction vector of the measuring rod axis in the part coordinate system of the five-axis roughness measurement system is represented as:

[0009] V p =R*V L

[0010]

[0011] Among them, V L Represents the direction vector of the measuring rod in the local coordinate system, V p The direction vector of the measuring rod in the part coordinate system;

[0012] The surface of the part to be tested is then discretized into a series of triangular facets, and the three vertices of the triangular facets are set to V0, V1, and V2 respectively, so as to obtain the expression of any point in the triangular facet as the formula:

[0013] T(u,v)=(1-uv)V0+uV1+vV2 (1)

[0014] Where u≥0, v≥0 and u+v≤1;

[0015] Then move the measuring rod axis with starting point O and direction V p Expressed as a formula:

[0016] R(t)=O+tV p (2)

[0017] Based on formula (1) and formula (2), the following formula is obtained through the ray-plane intersection algorithm:

[0018]

[0019] Substitute the coordinates of the measuring rod in the set direction of any measuring point on the contour line to be measured into formula (3). If formula (3) has a solution and satisfies formula (4), then the measuring rod in the set direction of the measuring point is unreachable. Otherwise, the measuring rod in the set direction of the measuring point is reachable.

[0020] Furthermore, the specific steps for generating the reachable area of ​​the measuring rod are as follows: the measuring rods in any direction corresponding to all measuring points on the contour line to be measured are respectively substituted into formula (3), and it is judged whether formula (4) is satisfied, so as to obtain data on whether the measuring rods in any direction corresponding to any point on the contour line to be measured are reachable, thereby generating the reachable area of ​​the measuring rod.

[0021] Further, the generating the planning path of the feeler according to the reachable area of the feeler specifically comprises the steps that: detecting whether there is at least one column of elements being 1 in the reachable area of the feeler, if yes, selecting the feeler direction corresponding to the column of elements as the planning direction of the feeler, and if not, dividing the profile line to be measured into a plurality of measurement lines, ensuring that there is at least one column of elements being 1 in the reachable area of the feeler corresponding to each measurement line, and selecting the feeler direction corresponding to the column of elements as the planning direction of the feeler.

[0022] Further, the step S3 specifically comprises the following steps:

[0023] Based on the principle that the sag error is not more than the micro-motion stroke of the measuring tip, the following formula is obtained:

[0024] max d(L i )>ε,i=2,…,j-1 (5)

[0025] Wherein, d(L i ) is the sag error of the sampling point, and ε is the micro-motion stroke of the measuring tip.

[0026] The profile line to be measured is sampled at equal intervals to obtain a plurality of sampling points, and each sampling point is checked in turn from the second sampling point to the last sampling point to see whether it satisfies the formula (5), if yes, the profile line to be measured is segmented at the current sampling point, and if not, the profile line to be measured is not segmented, until the check of the second last sampling point is completed.

[0027] Further, after the part to be measured is fixed on the measuring device, the method further comprises the steps that: a conventional feeler is used to establish the coordinates of the part, and then the conventional feeler is replaced by the roughness feeler.

[0028] Further, the measuring device is a three-coordinate measuring machine.

[0029] Further, the five-axis roughness measuring system comprises a three-coordinate measuring machine, a rotating measuring seat arranged on the three-coordinate measuring machine, and a roughness feeler arranged on the rotating measuring seat, the roughness feeler comprising a feeler and a measuring tip.

[0030] Further, an optical sensor is arranged in the feeler for acquiring the micro-motion signal of the feeler and outputting the micro-motion signal to the three-coordinate measuring machine.

[0031] The present application has the following beneficial effects:

[0032] The method for measuring the surface roughness of the complex curved part comprises the following steps: importing a data model of a part to be measured into a five-axis roughness measuring system, selecting a profile line to be measured on the surface of the data model of the part to be measured, defining an accessible region, analyzing the interference of a measuring rod on the profile line to be measured to generate the accessible region of the measuring rod, generating a planned path of the measuring rod according to the accessible region of the measuring rod, automatically generating a non-interference path in the measuring process, dividing the profile line to be measured into a plurality of measurement sequence line segments according to the principle that the arch height error of the profile line to be measured does not exceed the micro-motion stroke of the measuring tip, converting the complex curved line segment into a minimum number of straight line segments, improving the measurement efficiency, and ensuring that the direction of the measuring rod is non-interference in the same measurement sequence line segment in the measurement process to adapt to the measurement of the surface roughness of the part with a large curvature, fixing the part to be measured on the measuring equipment, controlling the measuring rod according to the planned path of the measuring rod, moving the measuring tip from the starting point to the ending point of the profile line to be measured, completing the surface roughness measurement of the part to be measured, and outputting the measurement result.

[0033] In addition to the objects, features and advantages described above, the present application has other objects, features and advantages. The present application will be described in further detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, illustrate the preferred embodiment of the application and assist in

[0035] Figure 1 is a flow chart of the method for measuring the surface roughness of the complex curved part according to the preferred embodiment of the present application;

[0036] Figure 2 is a schematic diagram of establishing a local coordinate system at a measuring point when defining the accessible region in the method for measuring the surface roughness of the complex curved part according to the preferred embodiment of the present application. DETAILED DESCRIPTION

[0037] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered below.

[0038] As Figure 1As shown, the method for measuring the surface roughness of complex curved surface parts of this embodiment includes the following steps: S1, importing the data model of the part to be measured into the five-axis roughness measurement system, and selecting the contour line to be measured on the surface of the data model of the part to be measured; S2, defining the reachable area, and analyzing the interference of the measuring rod on the contour line to be measured to generate the reachable area of ​​the measuring rod, and then generating the planned path of the measuring rod according to the reachable area of ​​the measuring rod; S3, dividing the contour line to be measured into multiple measurement sequence segments based on the principle that the bow height error in the contour line to be measured does not exceed the micro-motion stroke of the measuring tip; S4, fixing the part to be measured on the measuring equipment, controlling the measuring rod to work according to the planned path of the measuring rod, so that the measuring tip moves from the starting point to the end point of the contour line to be measured, completing the surface roughness measurement of the part to be measured, and outputting the measurement result.

[0039] like Figure 1 As shown, specifically, the method for measuring the surface roughness of complex curved surface parts of the present invention imports the data model of the part to be measured into the five-axis roughness measurement system, selects the contour line to be measured on the surface of the data model of the part to be measured; defines the reachable area, and analyzes the interference of the measuring rod on the contour line to be measured to generate the reachable area of ​​the measuring rod, and then generates the planning path of the measuring rod according to the reachable area of ​​the measuring rod, so as to realize the automatic generation of the interference-free path during the measurement process; divides the contour line to be measured into multiple measurement sequence line segments based on the principle that the bow height error in the contour line to be measured does not exceed the micro-movement stroke of the measuring tip, so that the complex curve segment can be converted into the minimum number of straight line segments, thereby improving the measurement efficiency and ensuring the measurement process In the method, the direction of the measuring rod has no interference within the same measurement sequence line segment, so as to adapt to the measurement of the surface roughness of parts with large curvature; the part to be measured is fixed on the measuring equipment, and the measuring rod is controlled to work according to the planned path of the measuring rod, so that the measuring tip moves from the starting point to the end point of the contour line to be measured, and the surface roughness measurement of the part to be measured is completed, and the measurement result is output; compared with the existing technology, this scheme realizes efficient and high-precision measurement of the surface roughness of complex curved parts by generating the reachable area of ​​the measuring rod and reasonably dividing the contour line to be measured, so as to output the best interference-free measurement path, thereby realizing high-efficiency and high-precision measurement of the surface roughness of complex curved parts, thereby being able to quickly measure batches of complex curved parts, with strong practicality and suitable for wide promotion and application.

[0040] It should be understood that, since this solution is mainly used to measure the surface roughness of complex curved parts, the contour line to be measured is usually a curve.

[0041] like Figure 2As shown, in this embodiment, in step S3, the specific steps of defining the reachable area are as follows: select any measuring point on the contour line to be measured to establish a local coordinate system, take the surface normal of the measuring point as the Z axis, take the tangent of the measurement sequence line segment of the measuring point as the X axis, and take the straight line passing through the measuring point and perpendicular to the Z axis and the X axis as the Y axis; obtain the angle ω between the projection line of the measuring rod in the XY plane and the X axis when the axis of the measuring tip coincides with the surface normal of the measuring point, and then take the right-hand coordinate system direction as the positive direction of ω, then the theoretical value range of ω is [ -π,π], the theoretical value range of ω is discretized into n intervals, and the reachable area of ​​the measuring point is represented as a 1×n row vector, in which any element is 0 or 1, where 0 represents that the measuring rod interferes with the part to be measured when ω is the angle, and 1 represents that the measuring rod interferes with the part to be measured when ω is the angle; the contour line to be measured is discretized into m sampling points, so that the reachable area of ​​the measuring rod is represented as an m×n matrix, in which each element of the matrix represents whether the measuring rod direction corresponding to the current measuring point is reachable or not with 0 or 1.

[0042] Specifically, by defining the reachable area, the reachable area of ​​the stylus is subsequently generated. When performing roughness measurement, the reachable area of ​​the stylus is used to analyze the interference-free situation during the measurement process, so that there is no interference between the stylus and the part to be measured.

[0043] like Figure 2 As shown, in this embodiment, the specific steps of analyzing the interference of the measuring rod on the contour line to be measured are:

[0044] The direction vectors of the X-axis, Y-axis and Z-axis in the local coordinate system in the coordinate system of the part to be measured in the five-axis roughness measurement system are expressed as f = [f x , f y , f z ] T , k=[k x , k y , k z ] T ,n=[n x , n y , n z ] T , and the included angle θ between the stylus axis and the stylus tip axis is obtained. The direction vector of the stylus axis in the coordinate system of the part to be measured of the five-axis roughness measurement system is expressed as:

[0045] V p =R*V L

[0046]

[0047] Among them, V L Represents the direction vector of the measuring rod in the local coordinate system, V pThe direction vector of the measuring rod in the part coordinate system;

[0048] The surface of the part to be tested is then discretized into a series of triangular facets, and the three vertices of the triangular facets are set to V0, V1, and V2 respectively, so as to obtain the expression of any point in the triangular facet as the formula:

[0049] T(u,v)=(1-uv)V0+uV1+vV2 (1)

[0050] Where u≥0, v≥0 and u+v≤1;

[0051] Then move the measuring rod axis with starting point O and direction V p Expressed as a formula:

[0052] R(t)=O+tV p (2)

[0053] Based on formula (1) and formula (2), the following formula is obtained through the ray-plane intersection algorithm:

[0054]

[0055] Substitute the coordinates of the measuring rod in the set direction of any measuring point on the contour line to be measured into formula (3). If formula (3) has a solution and satisfies formula (4), then the measuring rod in the set direction of the measuring point is unreachable. Otherwise, the measuring rod in the set direction of the measuring point is reachable.

[0056] Specifically, a coordinate system is established to construct a mathematical model of the measuring rod axis and the surface of the part to be measured, and an intersection operation is performed to determine the interference between the measuring rod and the part to be measured.

[0057] In this embodiment, the specific steps for generating the reachable area of ​​the measuring rod are as follows: the measuring rods in any direction corresponding to all measuring points on the contour line to be measured are respectively substituted into formula (3), and it is determined whether formula (4) is satisfied, so as to obtain data on whether the measuring rods in any direction corresponding to any point on the contour line to be measured are reachable, thereby generating the reachable area of ​​the measuring rod.

[0058] Specifically, after the reachable area is defined in the measurement system, the reachable area of ​​the measuring rod is generated by performing an intersection operation on the axis of the measuring rod and the surface of the part to be measured, thereby improving data support for the subsequent generation of the planning path of the measuring rod.

[0059] In the embodiment, generating the planning path of the feeler according to the reachable area of the feeler specifically includes the following steps: detecting whether there is at least one column of elements being 1 in the reachable area of the feeler, if there is, selecting the feeler direction corresponding to the column of elements as the planning direction of the feeler, and if there is not, dividing the to-be-measured profile line into a plurality of measurement sequence line segments, and ensuring that there is at least one column of elements being 1 in the reachable area of the feeler corresponding to each measurement sequence line segment, and selecting the feeler direction corresponding to the column of elements as the planning direction of the feeler.

[0060] Specifically, whether the to-be-measured profile line needs to be divided is determined according to the reachable area of the feeler, so as to ensure that there is no interference between the feeler and the to-be-measured part during roughness measurement.

[0061] In the embodiment, step S3 specifically includes the following steps:

[0062] Based on the principle that the bow error does not exceed the feeler tip micro motion stroke, the following formula is obtained:

[0063] max d(L i )>ε,i=2,…,j-1 (5)

[0064] wherein d(L i ) is the bow error of the sampling point, and ε is the feeler tip micro motion stroke.

[0065] The to-be-measured profile line is sampled at equal intervals to obtain a plurality of sampling points, and each sampling point is checked in turn from the second sampling point to the last sampling point according to formula (5), if the formula is satisfied, the to-be-measured profile line is segmented at the current sampling point, if the formula is not satisfied, the to-be-measured profile line is not segmented, and the checking is completed until the second last sampling point is checked.

[0066] Specifically, by dividing the to-be-measured profile line into a plurality of measurement sequence line segments, it is ensured that the feeler direction has no interference in the same measurement sequence line segment, and the division is realized based on the principle that the bow error does not exceed the feeler tip micro motion stroke, so that the number of measurement sequence line segments is minimized, thereby maximizing the measurement efficiency.

[0067] It should be understood that j is the serial number of the last sampling point, and i is the serial number of the current sampling point.

[0068] In the embodiment, after the to-be-measured part is fixed on the measuring device, the following step is further included: establishing a part coordinate system by using a conventional feeler, and then replacing the conventional feeler with a roughness feeler.

[0069] In the embodiment, the measuring device is a three-coordinate measuring machine, so that the part coordinate system and the local coordinate system of the measuring point can be quickly established by the three-coordinate measuring machine, and the reachable area of the feeler can be quickly generated, so as to plan the best measurement path.

[0070] In the embodiment, the five-axis roughness measurement system comprises a coordinate measuring machine, a rotary measuring seat arranged on the coordinate measuring machine, and a roughness measuring needle arranged on the rotary measuring seat, the roughness measuring needle comprising a measuring rod and a measuring tip. Specifically, after the part to be measured is fixed on the table surface of the coordinate measuring machine, the measuring tip axis coincides with the normal direction of the measured point, the measuring tip slightly touches the measured surface and is always in contact with the measured surface to produce a slight deformation through the coordinate measuring machine.

[0071] In the embodiment, an optical sensor is arranged in the measuring rod to obtain the micro-motion signal of the measuring rod and output to the coordinate measuring machine. Specifically, when the measuring tip moves on the measured surface of the part to be measured, the up-and-down micro-motion thereof can reflect the fluctuation of the part surface, the micro-motion signal is obtained through the optical sensor in the measuring rod, and the micro-topography information of the part surface is output, and the measurement result is generated through the coordinate measuring machine.

[0072] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of measuring surface roughness of a complex curved part surface, characterized by, The method comprises the following steps: S1, importing the data model of the part to be measured into a five-axis roughness measurement system, and selecting a profile line to be measured on the surface of the data model of the part to be measured; S2, defining the reachable region and analyzing the interference of the measuring rod on the profile line to be measured to generate the reachable region of the measuring rod, and then generating the planning path of the measuring rod according to the reachable region of the measuring rod; S3, dividing the profile line to be measured into a plurality of measurement sequence line segments according to the principle that the arch error in the profile line to be measured does not exceed the micro-motion stroke of the measuring tip; S4, fixing the part to be measured on the measuring device, controlling the measuring rod to work according to the planning path of the measuring rod, so that the measuring tip moves from the starting point to the ending point of the profile line to be measured, and the surface roughness measurement of the part to be measured is completed, and the measurement result is output; In step S3, the specific steps of defining the reachable region are as follows: A local coordinate system is established on any measurement point on the profile line to be measured, the normal of the surface of the measurement point is taken as the Z axis, the tangent of the measurement sequence line segment of the measurement point is taken as the X axis, and the straight line passing through the measurement point and perpendicular to the Z axis and the X axis is taken as the Y axis; The angle between the projection line of the measuring rod in the X-Y plane and the X axis when the measuring tip axis coincides with the normal of the curved surface of the measuring point , the positive direction of the right-hand coordinate system is , the theoretical value range of is [-π, π], the theoretical value range of is discretized into n intervals, and the reachable area of the measuring point is represented as a 1×n row vector, wherein any element in the row vector is 0 or 1, wherein 0 represents that the measuring rod interferes with the measured part when ω is the angle, and 1 represents that the measuring rod does not interfere with the measured part when ω is the angle. The profile line to be measured is discretely represented as m sampling points, and the reachable region of the measuring rod is represented as an m*n matrix, each element of the matrix represents that the measuring rod in the current direction is not reachable, and each element of the matrix represents that the measuring rod in the current direction is reachable.

2. The method of claim 1, wherein The specific steps of analyzing the interference of the measuring rod on the profile line to be measured are as follows: The direction vectors of the X axis, the Y axis and the Z axis in the local coordinate system in the direction vector of the measured part coordinate system of the five-axis roughness measurement system are respectively represented as , , , and the included angle between the measuring rod axis and the measuring tip axis is obtained The direction vector of the measuring rod axis in the direction vector of the measured part coordinate system of the five-axis roughness measurement system is represented as: ； wherein f is a vector in the X-axis direction, k is a vector in the Y-axis direction, and n is a vector in the Z-axis direction, denotes a direction vector of the probe direction in the local coordinate system, denotes a direction vector of the probe direction in the part coordinate system, and R is a matrix abbreviation, is an angle between the projection of the probe axis in the XY plane of the part coordinate system of the five-axis roughness measurement system and the X-axis. The surface of the part to be measured is discretized into a series of triangular facets, and the three vertex coordinates of the triangular facets are respectively set as , , to obtain the representation of any point in the triangular facet as formula: ； wherein, is a coordinate of any point within the triangle patch, is a first geometric feature variable parameter, is a second geometric feature variable parameter, and ; The measuring rod axis is then defined by the origin O and the direction is expressed by the formula: ； wherein is a function expression of the measuring rod axis, t is a geometric feature variable parameter three; Based on formulas (1) and (2), the following formula is obtained by ray-plane intersection algorithm: ； ； The coordinates of the measuring rod in the set direction of any measurement point on the profile line to be measured are brought into formula (3), if formula (3) has a solution and satisfies formula (4), the measuring rod in the set direction of the measurement point is not reachable, otherwise, the measuring rod in the set direction of the measurement point is reachable.

3. The method of claim 2, wherein The specific steps of generating the reachable region of the measuring rod are as follows: The measuring rod in any direction corresponding to all measurement points on the profile line to be measured is respectively brought into formula (3), and it is judged whether formula (4) is satisfied, so as to obtain the data whether the measuring rod in any direction corresponding to any point on the profile line to be measured is reachable, thereby generating the reachable region of the measuring rod.

4. The method of claim 3, wherein The specific steps of generating the planning path of the measuring rod according to the reachable region of the measuring rod include the following steps: It is detected whether there is at least one column element being 1 in the reachable region of the measuring rod, if there is, the column element corresponding to the planning direction of the measuring rod is selected, if not, the profile line to be measured is divided into a plurality of measurement lines, and it is ensured that there is at least one column element being 1 in the reachable region of the measuring rod corresponding to each measurement line, and the column element corresponding to the planning direction of the measuring rod is selected.

5. The method of claim 1-3, wherein Step S3 specifically includes the following steps: Based on the principle that the arch error does not exceed the micro-motion stroke of the measuring tip, the following formula is obtained: ； wherein, is the sag error of the sampling point, is the measurement tip micro-motion stroke, j is the serial number of the last sampling point, and i is the serial number of the current sampling point. The profile line to be measured is sampled at equal intervals to obtain a plurality of sampling points, and the second sampling point is taken as a starting point to check whether each sampling point satisfies formula (5) in turn, if it satisfies, the profile line to be measured is segmented at the current sampling point, if it does not satisfy, it is not segmented, and the checking of the last second sampling point is completed.

6. The method of claim 1-3, wherein After the part to be measured is fixed on the measuring device, the following steps are further included: The conventional probe is replaced by a roughness probe after establishing the part coordinate system by using the conventional probe.

7. The method of claim 1-3, wherein The measuring device is a three-coordinate measuring machine.

8. The method of claim 1-3, wherein The five-axis roughness measuring system comprises a three-coordinate measuring machine, a rotary measuring seat arranged on the three-coordinate measuring machine, and a roughness probe arranged on the rotary measuring seat.

9. The method of claim 1, wherein, An optical sensor is arranged in the measuring rod for acquiring micro-motion signals of the measuring rod and outputting the same to the three-coordinate measuring machine.

Images