Method for determining the dimensions of a mechanical part

Abstract

A method (100) for determining a dimension (D) of a mechanical part (PM1, PM2), comprising the steps of measuring (101) the position of points on an edge of the part's cross-section, determining (102) a skeleton curve (CSQ), comprising the steps of calculating (1021) a triangulation of the points of the cross-section curve (CS), and for each triangle of the triangulation, determining (1022) a center (CT) and a centroid (BT) of said triangle, filtering (1023) the centers (CT) based on the centroids (BT) to obtain a set of filtered centers (CTF), the determined skeleton curve (CSQ) comprising the set of filtered centers (CTF), and determining (103) the dimension (D) of the mechanical part at a skeleton point on the skeleton curve (CSQ) as a function of the position of said skeleton point on the skeleton curve (CSQ). Figure 2

Claims

Demands

1. A method (100) for determining a dimension (D) of a mechanical part (PMI, PM2), the method being implemented by computer and comprising the following steps: - measuring (101) the position, in a plane of a section of the part, of a plurality of points positioned on an edge of the section of the part, the edge of the section of the part forming a section curve (CS) in said plane, - determining (102) a skeleton curve (CSQ) comprising a plurality of skeleton points, the determination (102) of the skeleton curve (CSQ) comprising the following steps: - calculating (1021) a triangulation of the plurality of points of the section curve (CS), the triangulation comprising a set of triangles, each triangle of the set of triangles being formed by three points of the plurality of points of the section curve (CS), - for each triangle of the triangulation, determining (1022) a center (CT) of said triangle,defined by the center of a circle circumscribed about said triangle, and a barycenter (BT) of said triangle, defined by the barycenter of the vertices of said triangle, so as to obtain a set of barycenters (BT) and a set of centers (CT), each triangle of the triangulation corresponding to a barycenter (BT) of the set of barycenters and to a center (CT) of the set of centers, - filtering (1023) of the centers (CT), on the basis of the barycenters (BT), to obtain a set of filtered centers (CTF), the determined skeleton curve (CSQ) comprising the set of filtered centers (CTF), - determination (103) of the dimension (D) of the mechanical part, at a skeleton point of the skeleton curve (CSQ), as a function of the position of said skeleton point on the skeleton curve (CSQ).

2. A method (100) according to claim 1, wherein said skeleton point is positioned at a first distance (Dl) from a first part (Bl) of the section curve (CS), and at a second distance (D2) from a second part (B2) of the section curve (CS), the first distance (Dl) and the second distance (D2) being measured transversely to the skeleton curve, the dimension (D) of the mechanical part of said skeleton point of the skeleton curve (CSQ) being equal to a sum of the first distance (D1) and the second distance (D2).

3. A method (100) according to any one of claims 1 or 2, wherein the filtering step (1023) comprises: - determining (10231) that a barycenter of a triangle is an inconsistent barycenter, and that the triangle corresponding to the inconsistent barycenter is an inconsistent triangle, and that the center of the inconsistent triangle is an inconsistent center, - removing (10232) said inconsistent center from the set of centers, to obtain the filtered set of centers.

4. A method (100) according to any one of claims 1 to 3, wherein the skeleton curve determination step (102) comprises an extrapolation (1024) of complementary points from the filtered center set (CTF), so that the skeleton curve (CSQ) comprises the complementary points (PC) and the filtered center set (CTF).

5. Method (100) according to claim 4, wherein the extrapolation step (1024) of complementary points (CP) includes a scheduling (1024bis) of the points of the filtered center set (CTF).

6. Method (100) according to claim 3, wherein the step of determining (10231) that a barycenter of a triangle is an inconsistent barycenter comprises: - the construction (102311), from the points of the section curve (CS), of a filtering polygon (PF); - the determination (102312) that a barycenter is inconsistent if it is outside said filtering polygon (PF).

7. A method (100) according to claim 6, wherein the construction step (102311) of the filtering polygon (PF) comprises the determination (1023111) of a set of vertices (SPF) of said filtering polygon (PF), each vertex (SPF) being positioned in a defined direction (DT) from a subset of points (SEP) of the section curve (CS), at a predetermined distance from said subset of points (SEP) of the section curve (CS), the defined direction (DT) from the subset of points (SEP) of the section curve (CS) being transverse to a portion of the section curve (CS) passing through the points of said subset of points (SEP) of the section curve (CS).

8. Method (100) according to claim 7, wherein the direction defined (DT) from the subset of points (SEP) of the section curve is defined by an eigenvector of a covariance matrix calculated from the coordinates of the points of the subset of points (SEP) of the section curve (CS).

9. A method (100) according to any one of claims 7 or 8, wherein the section curve (CS) is closed so as to delimit an interior of the section curve, and wherein the vertex (SPF) of the filtering polygon (PF) is positioned in the direction (DT) transverse to the portion of the section curve (CS) passing through the points of said subset of points (SEP) of the section curve (CS), such that an oriented segment (SO, SOI, SO2) of said portion of the section curve (CS) towards said vertex (SPF), along said transverse direction (DT), is oriented towards the interior of the section curve (CS).

10. A method (100) according to the preceding claim, further comprising a step of reversing the orientation of said oriented segment (SO2), when said oriented segment (SO2) intersects the section curve (CS) at an intersection point (PI2) and when an intermediate point (PI2') is located outside the section curve, said intermediate point (PI2') being positioned between an origin point (PO2) of the oriented segment (SO2) and said intersection point (PI2), said origin point (PO2) being located on said portion of the section curve (CS), said reversal of the orientation generating an inverted oriented segment (SO2I), in the opposite direction to the oriented segment (SO2), said inverted oriented segment (SO2I) being directed towards the inside of the section curve (CS).

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