Method for determining the dimension of a mechanical part

Abstract

Method (100) for determining a dimension (D) of a mechanical part (PM1, PM2), comprising the steps of measuring (101) a position of points on an edge of the section of the part, determining (102) a skeleton curve (CSQ), comprising the steps of calculating (1021) a triangulation of the points of the section curve (CS), and for each triangle of the triangulation, determining (1022) a center (CT), and a barycenter (BT) of said triangle, filtering (1023) 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), and determining (103) 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). Figure 2

Claims

Claims

1. 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) a 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 to 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. 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 at said skeleton point of the skeleton curve (CSQ) being equal to a sum of the first distance (Dl) 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 incoherent barycenter, and that the triangle corresponding to the incoherent barycenter is an incoherent triangle, and that the center of the incoherent triangle is an incoherent center, - removing (10232) said incoherent center from the set of centers, to obtain the set of filtered centers.

4. Method (100) according to one of claims 1 to 3, in which the step of determining (102) the skeleton curve comprises an extrapolation (1024) of complementary points from the set of filtered centers (CTF), so that the skeleton curve (CSQ) comprises the complementary points (PC) and the set of filtered centers (CTF).

5. Method (100) according to claim 4, wherein the step of extrapolating (1024) complementary points (PC) comprises an ordering (1024bis) of the points of the set of filtered centers (CTF).

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

7. Method (100) according to claim 6, wherein the step of constructing (102311) the filtering polygon (PF), comprises determining (1023111) 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, in which 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. Method (100) according to one of claims 7 or 8, in which the section curve (CS) is closed so as to delimit an interior of the section curve, and in which 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), so that an oriented segment (SO, SOI, S02) of said portion of the section curve (CS) towards said vertex (SPF), in said transverse direction (DT), is oriented towards the interior of the section curve (CS).

10. Method (100) according to the preceding claim, further comprising a step of inverting the orientation of said oriented segment (SO2), when said oriented segment (SO2) intersects the section curve (CS) at a point of intersection (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 point of intersection (PI2), said origin point (PO2) being located on said portion of the section curve (CS), said inversion 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).

Images