Axial positioning method, device and system for annular wave-shaped part

Abstract

The invention relates to an axial positioning method, device and system for an annular wave-shaped part, and belongs to the technical field of fine micropore laser machining of the annular wave-shaped part. The method comprises the steps that the highest point and the lowest point of a generatrix of the annular wave-shaped part are positioned respectively; the annular wave-shaped part is scanned in the first direction, and bus position information of the annular wave-shaped part is obtained; wherein the first direction is parallel to the direction of a connecting line between the highest point of the bus and the lowest point of the bus; and reverse fitting is carried out according to the bus position information, the bus profile of the annular wave-shaped part is obtained, and the bus profile of the annular wave-shaped part comprises a plurality of wave crests and a plurality of wave troughs on the bus profile of the annular wave-shaped part. According to the method, reverse fitting is carried out on the generatrix of the annular wave-shaped part based on the scanning result, the influence of wave pitch deviation generated by local deformation of the annular wave-shaped part on the positioning precision and the machining precision is avoided, and the positioning precision and the part machining quality are guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine micro-hole laser processing of annular corrugated parts, and in particular relates to an axial positioning method, device and system for annular corrugated parts. Background Art

[0002] As one of the most advanced processing and manufacturing technologies, laser processing technology has the advantages of high precision, high controllability and high efficiency. It can solve processing problems such as cutting of difficult-to-process materials in special machinery manufacturing, efficient processing of group holes in large thin-walled parts, high-precision cutting of air film holes in parts, and etching of three-dimensional complex surfaces.

[0003] In the processing of conventional cylindrical parts, the top or bottom surface is usually selected as the reference. However, compared with conventional parts, the tube wall of annular corrugated parts is extremely thin and prone to deformation, which affects the positioning accuracy. The poor hole processing quality and position accuracy of annular corrugated parts seriously affect the performance and quality of the overall parts. In addition, due to the large number of holes processed on annular corrugated parts, ensuring the hole positioning accuracy is the main difficulty in processing such parts when the overall roundness is large and the wave height or wave distance deviation is large.

[0004] At present, in the process of making holes in annular wave-shaped parts, one positioning method is to make manual adjustments based on reference points or feature points on the fixture. However, this method completely relies on the experience of the operator, and the positioning accuracy of complex curved surface parts whose feature points are difficult to determine is poor. In addition, since positioning through feature points can only meet the positioning requirement of one position, the error caused by the deformation of the part itself is not taken into account, the consistency of positioning accuracy and processing angle is also poor, and the efficiency is also low. Another positioning method requires the preparation of special fixtures to reduce the deformation of the workpiece, and then the processing is based on computer-aided manufacturing software. This method relies on special fixtures, and the design and manufacturing costs are high. In addition, both the fixtures and computer-aided manufacturing software are difficult to handle actual local deformations, and ultimately it is still difficult to guarantee positioning accuracy and part processing quality. Therefore, there is a need for a method and system that can improve the axial positioning accuracy of annular wave-shaped parts. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides an axial positioning method and system for annular corrugated parts. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] The present invention provides an axial positioning method for an annular corrugated part, comprising:

[0007] Locate the highest point and the lowest point of the busbar of the annular wave-shaped part respectively;

[0008] Scanning the annular wave-shaped part along a first direction to obtain the busbar position information of the annular wave-shaped part; the first direction is parallel to the direction of the line connecting the highest point of the busbar and the lowest point of the busbar;

[0009] Reverse fitting is performed according to the busbar position information to obtain the busbar profile of the annular wave-shaped part; the busbar profile of the annular wave-shaped part includes a plurality of wave crests and a plurality of wave troughs on the busbar profile of the annular wave-shaped part.

[0010] In one embodiment of the present invention, respectively locating the highest point and the lowest point of the busbar of the annular corrugated component comprises:

[0011] Fix the annular corrugated part on a horizontal workbench;

[0012] The highest point of the generatrix is ​​set as the first measuring point, and the positions of the first measuring point along the second direction and the third direction are measured respectively to locate the highest point of the generatrix of the annular corrugated part; wherein the second direction is the surface normal direction along the annular corrugated part, and the third direction is the axial direction along the annular corrugated part;

[0013] The lowest point of the busbar is set as the second measuring point, and the positions of the second measuring point along the second direction and along the third direction are measured respectively to locate the lowest point of the busbar of the annular corrugated part.

[0014] In one embodiment of the present invention, reverse fitting is performed according to the busbar position information to obtain the busbar profile of the annular wave-shaped part, including:

[0015] According to the busbar position information, the B-spline curve fitting method is adopted to obtain the B-spline curve of the busbar of the annular wave-shaped part;

[0016] According to the B-spline curve of the generatrix of the annular corrugated part, the generatrix contour of the annular corrugated part is obtained by using the second-order difference recognition algorithm.

[0017] In one embodiment of the present invention, a B-spline curve fitting method is used according to the busbar position information to obtain a B-spline curve of the annular wave-shaped part, including:

[0018] The order, control point distribution area, weight value and node of the B-spline curve are set respectively, and a number of expected contour points are generated according to the generatrix position information;

[0019] The maximum distance and the maximum error of the B-spline curve are set respectively, and the B-spline curve of the annular wave-shaped part is obtained according to a number of expected contour points.

[0020] In one embodiment of the present invention, the expression of the B-spline curve is:

[0021]

[0022] Where, C(u) is the parametric equation of the B-spline curve; P i is the i-th control point; N i,p (u) is the basis function of the i-th p-th order B-spline curve with the i-th control point; i is the first ordinal parameter; p is the order parameter; u is the control point on the B-spline curve; and n is the total number of control points.

[0023] In one embodiment of the present invention, the expression of the basis function of the B-spline curve is:

[0024]

[0025] Among them, N i,0 (u) is the basis function of the i-th 0th degree B-spline curve of the i-th control point; u i is the i-th control point on the B-spline curve.

[0026] In one embodiment of the present invention, according to the B-spline curve of the generatrix of the annular wave-shaped part, a second-order difference recognition algorithm is used to obtain the generatrix profile of the annular wave-shaped part, including:

[0027] According to the B-spline curve of the generatrix of the annular wave-shaped part, convolution calculation is performed based on the second-order difference operator, and feature extraction is performed to obtain the edges and feature points on the B-spline curve;

[0028] The edge curvature is analyzed according to the edge and the characteristic point to obtain the generatrix contour of the annular corrugated part; wherein the generatrix contour of the annular corrugated part includes a plurality of convex points and concave points, the convex points are the wave crest positions on the generatrix contour of the annular corrugated part, and the concave points are the wave trough positions on the generatrix contour of the annular corrugated part.

[0029] In one embodiment of the present invention, the expression of the second-order difference recognition algorithm is:

[0030] f″(j)=f(j+1)-2f(j)+f(j-1);

[0031]

[0032] Wherein, f(j) is the gray value of the jth point on the B-spline curve; j is the first ordinal parameter; f″(j) is the second-order difference dispersion function of f(j); is a second-order difference operator; x is the first parameter; y is the second parameter; is the partial derivative function.

[0033] The present invention also provides an axial positioning device for an annular corrugated part, using the above-mentioned axial positioning method for annular corrugated parts, the axial positioning device comprises: a distance measurement module and a data acquisition and processing module;

[0034] The distance measuring module is used to respectively locate the highest point and the lowest point of the busbar of the annular wave-shaped part, and scan the annular wave-shaped part along the first direction to obtain the busbar position information of the annular wave-shaped part;

[0035] The data acquisition and processing module is used to perform reverse fitting based on the busbar position information to obtain the busbar profile of the annular wave-shaped part.

[0036] The present invention also provides an axial positioning system for annular corrugated parts, comprising: a processing machine tool and the above-mentioned axial positioning device for annular corrugated parts;

[0037] The distance measuring module is arranged on the motion module of the processing machine tool, and moves along with the motion module of the processing machine tool to obtain the busbar position information of the annular wave-shaped part in real time through motion scanning.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The axial positioning method for annular corrugated parts of the present invention realizes the generatrix position information of complex workpieces such as annular corrugated parts based on simple scanning, and then reversely fits the generatrix of the annular corrugated parts based on the scanning results, and obtains the peaks and troughs after deformation by fitting the deformed contour of the annular corrugated parts, thereby solving the influence of the wave distance deviation caused by local deformation of the annular corrugated parts on the positioning accuracy and processing accuracy, thereby ensuring the positioning accuracy and part processing quality.

[0040] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of an existing annular wave-shaped part;

[0042] Figure 2 It is a structural front view of an existing annular corrugated part;

[0043] Figure 3 is a schematic diagram of the error between the theoretical position and the actual position due to local deformation;

[0044] Figure 4 is a flow chart of an axial positioning method for an annular corrugated part provided by an embodiment of the present invention;

[0045] Figure 5 is a flow chart of step 1 of the axial positioning method for annular corrugated parts provided by an embodiment of the present invention;

[0046] Figure 6 is a flow chart of step 3 of the axial positioning method for annular corrugated parts provided by an embodiment of the present invention;

[0047] Figure 7 is a flow chart of step 3.1 of the axial positioning method for annular corrugated parts provided by an embodiment of the present invention;

[0048] Figure 8 is a flow chart of step 3.2 of the axial positioning method for annular corrugated parts provided by an embodiment of the present invention;

[0049] Figure 9a is a schematic diagram of a B-spline curve obtained by automatic fitting provided by an embodiment of the present invention;

[0050] Figure 9b is a schematic diagram of a B-spline curve obtained by manual fitting provided in an embodiment of the present invention;

[0051] Fig.9c is a schematic diagram of the deviation of a B-spline curve obtained by automatic fitting provided by an embodiment of the present invention;

[0052] Figure 9d is a schematic diagram of the deviation of a B-spline curve obtained by manual fitting provided in an embodiment of the present invention;

[0053] Fig.10 This is a schematic diagram of the generatrix profile of a ring-shaped corrugated part obtained by using the positioning method and positioning system provided by an embodiment of the present invention;

[0054] Fig.11 It is a structural block diagram of an axial positioning system for annular corrugated parts provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description of an axial positioning method, device and system for annular corrugated parts proposed in accordance with the present invention, in combination with the accompanying drawings and specific implementation methods.

[0056] The above and other technical contents, features and effects of the present invention are clearly presented in the following detailed description of the specific implementation modes in conjunction with the accompanying drawings. Through the description of the specific implementation modes, the technical means and effects adopted by the present invention to achieve the predetermined purpose can be more deeply and specifically understood. However, the attached drawings are only for reference and explanation purposes and are not used to limit the technical solutions of the present invention.

[0057] Embodiment 1

[0058] like Figure 1 and Figure 2 As shown in the figure, the annular corrugated part is usually a thin-walled cylindrical part, which is composed of a number of corrugated circular rings connected in sequence. Wave crests and troughs are formed between two adjacent corrugated circular rings. When processing holes on the annular corrugated part along the axial direction, the deviation between the wave crests and troughs and the wave distance of the corrugated circular rings, or the local deformation of the annular corrugated part itself, can easily lead to inaccurate positioning, resulting in a deviation between the actual positioning position and the theoretical position, such as Figure 3 As shown, it further affects the processing accuracy during the hole making process.

[0059] In view of this, if Figure 4 As shown, the first aspect of the present invention provides an axial positioning method for an annular corrugated part, comprising the steps of:

[0060] Step 1: Locate the highest point and the lowest point of the busbar of the annular wave-shaped part respectively.

[0061] like Figure 5 As shown, in this embodiment, step 1 includes:

[0062] Step 1.1: Fix the ring-shaped corrugated part on a horizontal workbench;

[0063] Step 1.2: Set the highest point of the generatrix as the first measuring point, and measure the positions of the first measuring point along the second direction and the third direction respectively to locate the highest point of the generatrix of the annular corrugated part; wherein the second direction is the surface normal direction of the annular corrugated part, and the third direction is the axial direction of the annular corrugated part;

[0064] Step 1.3: Set the lowest point of the busbar as the second measuring point, and measure the position of the second measuring point along the second direction and along the third direction respectively to locate the lowest point of the busbar of the annular corrugated part.

[0065] Specifically, the position information of the highest point and the lowest point of the busbar of the annular corrugated part is obtained through measurement, that is, the position of the highest point and the lowest point of the busbar along the surface normal direction and the axial direction of the annular corrugated part.

[0066] Step 2: Scan the annular wave-shaped part along a first direction to obtain the busbar position information of the annular wave-shaped part; the first direction is parallel to the direction of the line connecting the highest point of the busbar and the lowest point of the busbar.

[0067] Specifically, scanning is performed at a uniform speed along the first direction, from the highest point of the busbar of the annular wave-shaped part to the lowest point of the busbar, or from the lowest point of the busbar of the annular wave-shaped part to the highest point of the busbar. The scanning results are collected in real time during the scanning process to obtain the busbar position information of the annular wave-shaped part.

[0068] Step 3: Perform reverse fitting according to the busbar position information to obtain the busbar profile of the annular wave-shaped part; the busbar profile of the annular wave-shaped part includes a plurality of peaks and a plurality of troughs on the busbar profile of the annular wave-shaped part.

[0069] like Figure 6 As shown, in this embodiment, step 3: includes:

[0070] Step 3.1: According to the busbar position information, the B-spline curve fitting method is used to obtain the B-spline curve of the busbar of the annular wave-shaped part;

[0071] like Figure 7 As shown, in this embodiment, step 3.1: includes:

[0072] Step 3.1.1: Set the order, control point distribution area, weight value and node of the B-spline curve respectively, and generate several expected contour points according to the generatrix position information.

[0073] Specifically, the order of the B-spline curve determines the smoothness of the generated curve, and the entire curve is within the range of its control points. The control point distribution area is similar to a frame that wraps the curve. The weight value determines the degree to which the generated curve deviates from the control point, and the node determines the distribution method of the curve.

[0074] Optionally, the bus position information can be automatically fitted based on an external processing device. During automatic fitting, since the weights of all control points are the same, the attraction of all control points to the curve remains consistent. Nodes can also be set based on automatic fitting, which can enhance flexibility, improve fitting accuracy and simplify operation. Weight values ​​can also be set based on automatic fitting to adapt to the differences in bus position information and to meet accuracy requirements. At the same time, the bus position information can also be manually fitted based on manual settings, which is more conducive to improving fitting accuracy and flexibility, but it may also increase the complexity of the settings and require more time to adjust. Figure 9a and Figure 9b As shown in Figure 2, the trajectory of the B-spline curve obtained by automatic fitting or manual fitting is consistent with the trajectory of the control point. Fig.9c and Figure 9d As shown, the B-spline curve obtained by manual fitting has a smaller deviation.

[0075] Step 3.1.2: Set the maximum distance and maximum error of the B-spline curve respectively, and obtain the B-spline curve of the annular corrugated part according to a number of expected contour points.

[0076] Specifically, in order to improve the accuracy of the B-spline curve, the maximum distance and maximum error also need to be considered. The maximum distance refers to the maximum distance between two expected contour points. The maximum distance specifies the accuracy of the curve fitting. A smaller value will make the generated curve fit the original contour more accurately, but it may increase the computational complexity and time. A larger value will produce a simpler curve, but may lose some details. The maximum error refers to the maximum distance between the expected contour point and the actual generated B-spline curve. It is mainly used to control the distance between the curve and the expected contour point. The smaller this value is, the smaller the distance between the generated curve and the original contour, the better the fitting effect, and it helps to prevent the curve from deviating too far from the original contour. By setting the maximum distance and maximum error, the approximation of the B-spline curve can be further optimized while maintaining the overall shape of the B-spline curve. The lower the maximum distance and maximum error, the better the approximation of the curve. At this time, all expected contour points should be accurately located on the curve.

[0077] In addition, one of the maximum distance and the maximum error can be ignored. When the maximum distance is ignored, the shape of the fitting curve depends on the original data, which is suitable for application scenarios with high requirements for the overall shape. When the maximum error is ignored, although the accuracy is sacrificed, the fitting speed is significantly improved, which is suitable for situations with high requirements for fitting speed.

[0078] In an optional implementation, the expression of the B-spline curve is:

[0079]

[0080] Where, C(u) is the parametric equation of the B-spline curve; P i is the i-th control point; N i,p (u) is the basis function of the i-th p-th order B-spline curve with the i-th control point; i is the first ordinal parameter; p is the order parameter; u is the control point on the B-spline curve; and n is the total number of control points.

[0081] In an optional implementation, the expression of the basis function of the B-spline curve is:

[0082] The expression of the zero-order basis function, that is, when p = 0:

[0083]

[0084] The expression of high-order basis function, that is, when p>0:

[0085]

[0086] Among them, N i,0 (u) is the basis function of the i-th 0th degree B-spline curve of the i-th control point; u i is the i-th control point on the B-spline curve; ui+1 is the i+1th control point on the B-spline curve; u i+p is the i+pth control point on the B-spline curve; u i+p+1 is the i+p+1th control point on the B-spline curve.

[0087] It can be seen from formula (1) to formula (3) that the fitted B-spline curve is determined by its order parameter p, weight vector and node vector. The higher the order parameter p, the wider the influence range of the basis function, and the higher the smoothness and complexity of the fitted curve.

[0088] It should be noted that the order of the B-spline curve, the control point distribution area, the weight value, the node, the maximum distance and the maximum error of this embodiment can be set accordingly according to the actual situation, and this embodiment does not impose any restrictions on this.

[0089] Step 3.2: According to the B-spline curve of the generatrix of the annular wave-shaped part, the generatrix contour of the annular wave-shaped part is obtained by using the second-order difference recognition algorithm.

[0090] like Figure 8 As shown, in this embodiment, step 3.2: includes:

[0091] Step 3.2.1: According to the B-spline curve of the generatrix of the annular wave-shaped part, convolution calculation is performed based on the second-order difference operator, and feature extraction is performed to obtain the edge and feature points on the B-spline curve;

[0092] Step 3.2.2: Analyze the edge curvature according to the edge and the feature point to obtain the generatrix contour of the annular corrugated part; wherein the generatrix contour of the annular corrugated part includes a plurality of convex points and concave points, the convex points are the peak positions on the generatrix contour of the annular corrugated part, and the concave points are the trough positions on the generatrix contour of the annular corrugated part.

[0093] The principle is to perform reverse fitting of the annular wave-shaped part based on the B-spline curve according to the generatrix contour obtained by scanning, that is, to obtain the B-spline curve of the generatrix of the annular wave-shaped part by fitting the scanning result, and then to obtain the generatrix contour of the annular wave-shaped part based on the second-order difference recognition algorithm, to determine the positions of the peaks and troughs on the generatrix contour, and finally to determine the actual axial and normal processing positions of the holes in the annular wave-shaped part based on the positions of the peaks and troughs.

[0094] In an optional implementation, the expression of the second-order difference recognition algorithm is:

[0095] For a one-dimensional signal, the discrete form of the second-order difference is expressed as:

[0096] f″(j)=f(j+1)-2f(j)+f(j-1) (4);

[0097] Wherein, f(j) is the gray value of the jth point on the B-spline curve; j is the first ordinal parameter; and f″(j) is the second-order difference dispersion function of f(j).

[0098] In a two-dimensional image, the second-order difference is usually implemented by the Laplacian operator, which is expressed as:

[0099]

[0100] in, is a second-order difference operator; x is the first parameter; y is the second parameter; is the partial derivative function.

[0101] It should be noted that the second-order difference recognition algorithm is an image processing method for detecting edges and feature points of grayscale change trends in an image. In the algorithm, the second-order derivative of the grayscale of the image is calculated to identify significant change locations, which can be used for edge detection and feature extraction. The operator used in the second-order difference recognition algorithm of this embodiment is not limited. For example, the Laplace operator is only used as an example, and the corresponding parameter settings can also be implemented by referring to existing related technologies.

[0102] The principle is that the process of obtaining the generatrix profile of the annular wave-shaped part can be divided into two steps. In the first step, convolution calculation is performed based on Laplace operator or similar operators, and zero crossing point and extreme value detection are combined to extract edges and feature points. In the second step, the edge curvature is analyzed and the curvature extreme value points are detected, that is, convex points and concave points are extracted and identified, and the position and curvature information is stored. Combining the advantages of edge detection and curvature analysis, the accurate identification of concave and convex points is achieved.

[0103] The generatrix profile of the annular corrugated part is obtained as follows: Fig.10 As shown in the figure, the busbar contour, convex points and concave points are represented respectively, where the concave points correspond to the troughs of the annular wave-shaped parts, and the convex points correspond to the peaks of the annular wave-shaped parts. Processing according to the busbar contour has higher accuracy and can solve the errors in the processing position of the busbar direction and the processing direction caused by the deformation of the parts. At the same time, for the processing of annular wave-shaped parts, the positioning accuracy and positioning time can be greatly improved.

[0104] The axial positioning method for annular corrugated parts of the present invention realizes the generatrix position information of complex workpieces such as annular corrugated parts based on simple scanning, and then reversely fits the generatrix of the annular corrugated parts based on the scanning results, and obtains the peaks and troughs after deformation by fitting the deformed contour of the annular corrugated parts, thereby solving the influence of the wave distance deviation caused by local deformation of the annular corrugated parts on the positioning accuracy and processing accuracy, thereby ensuring the positioning accuracy and part processing quality.

[0105] In other words, annular wave-shaped parts have difficulty in positioning after local deformation, but the positioning accuracy and processing accuracy are guaranteed by scanning-reverse fitting and using peak and trough positioning.

[0106] like Fig.11 As shown, based on the same inventive concept, the second aspect of the present invention proposes an axial positioning device for an annular corrugated part, using the axial positioning method for annular corrugated part of the first aspect;

[0107] The second aspect of the present invention is an axial positioning device for annular wave-shaped parts, comprising: a distance measuring module and a data acquisition and processing module; wherein the distance measuring module is used to respectively locate the highest point and the lowest point of the busbar of the annular wave-shaped part, and scan the annular wave-shaped part along a first direction to obtain the busbar position information of the annular wave-shaped part; the data acquisition and processing module is used to perform reverse fitting according to the busbar position information to obtain the busbar contour of the annular wave-shaped part.

[0108] Based on the same inventive concept, the third aspect of the present invention proposes an axial positioning system for annular wave-shaped parts, comprising: a processing machine tool and an axial positioning device for annular wave-shaped parts of the second aspect, wherein the ranging module is arranged on the motion module of the processing machine tool and moves with the motion module of the processing machine tool to obtain the busbar position information of the annular wave-shaped parts in real time through motion scanning.

[0109] Exemplarily, the distance measuring device may be a laser distance measuring device, such as a laser rangefinder.

[0110] It should be noted that the effective range of the distance measuring device should be greater than the maximum distance between the peak and the trough of the annular wave-shaped part, that is, the height difference between the highest point and the lowest point of the busbar of the annular wave-shaped part. On the premise of meeting the effective range, the smaller the range, the higher the accuracy.

[0111] The principle is that the laser rangefinder is fixed on the motion module of the processing machine tool, and the laser rangefinder is installed parallel to the normal of the annular wave-shaped part. The transmitting element emits several laser beams to the annular wave-shaped part, and then the receiving element of the laser rangefinder receives the laser beam reflected back from the surface of the annular wave-shaped part. The distance to the surface of the annular wave-shaped part is calculated by the time from the emission to the reception of the laser beam, thereby determining the position information of the corresponding position.

[0112] The annular wave-shaped part is fixed on the horizontal workbench of a processing machine tool, and the distance measuring module is arranged on the motion module of the processing machine tool. The distance measuring module moves along the axial direction and the surface normal direction of the annular wave-shaped part with the motion module of the processing machine tool. Specifically, the distance measuring module moves along the axial direction to the highest point of the busbar of the annular wave-shaped part, and moves along the normal direction to approach the highest point of the busbar so that the distance between the distance measuring module and the surface of the annular wave-shaped part is within its effective range, and the normal position is measured to obtain the highest point of the busbar, that is, the position information of the first measuring point; similarly, the distance measuring module moves along the axial direction to the lowest point of the busbar of the annular wave-shaped part, and moves along the normal direction to approach the lowest point of the busbar and measure the normal position to obtain the lowest point of the busbar, that is, the position information of the second measuring point.

[0113] Furthermore, driven by the motion module, the annular wave-shaped part is scanned in real time along the first direction to obtain the busbar position information of the annular wave-shaped part, and the positioning work of complex workpieces such as annular wave-shaped parts can be satisfied by simple scanning. Among them, the first direction is parallel to the direction of the line between the highest point of the busbar and the lowest point of the busbar, such as the motion scanning from the highest point of the busbar to the lowest point of the busbar, or the motion scanning from the lowest point of the busbar to the lowest point of the busbar.

[0114] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant is intended to cover non-exclusive inclusion, so that the article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the article or device including the elements. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The orientation or position relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0115] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for axial positioning of annular corrugated parts, characterized in that: include: Locate the highest point and the lowest point of the busbar of the annular wave-shaped part respectively; Scanning the annular corrugated part along a first direction to obtain busbar position information of the annular corrugated part; the first direction is parallel to the direction of a line connecting the highest point of the busbar and the lowest point of the busbar; Reverse fitting is performed based on the busbar position information to obtain the busbar profile of the annular corrugated part; the busbar profile of the annular corrugated part includes a plurality of wave crests and a plurality of wave troughs on the busbar profile of the annular corrugated part.

2. The axial positioning method for annular corrugated parts according to claim 1, characterized in that: Locate the highest and lowest points of the busbar of the annular wave-shaped parts, including: Fixing the annular corrugated part on a horizontal workbench; The highest point of the generatrix is ​​set as a first measuring point, and the positions of the first measuring point along a second direction and a third direction are measured respectively to locate the highest point of the generatrix of the annular corrugated part; wherein the second direction is a surface normal direction along the annular corrugated part, and the third direction is an axial direction along the annular corrugated part; The lowest point of the busbar is set as a second measuring point, and the positions of the second measuring point along the second direction and along the third direction are measured respectively to locate the lowest point of the busbar of the annular corrugated part.

3. The axial positioning method for annular corrugated parts according to claim 1, characterized in that: Performing reverse fitting according to the busbar position information to obtain the busbar profile of the annular wave-shaped part includes: According to the busbar position information, a B-spline curve fitting method is adopted to obtain a B-spline curve of the busbar of the annular wave-shaped part; According to the B-spline curve of the generatrix of the annular corrugated part, a second-order difference recognition algorithm is used to obtain the generatrix contour of the annular corrugated part.

4. The axial positioning method for annular corrugated parts according to claim 3, characterized in that: According to the busbar position information, a B-spline curve fitting method is used to obtain a B-spline curve of the annular wave-shaped part, including: The order, control point distribution area, weight value and node of the B-spline curve are respectively set, and a number of expected contour points are generated according to the generatrix position information; The maximum distance and the maximum error of the B-spline curve are respectively set, and the B-spline curve of the annular corrugated part is obtained according to a plurality of expected contour points.

5. The axial positioning method for annular corrugated parts according to claim 4, characterized in that: The expression of the B-spline curve is: Where, C(u) is the parametric equation of the B-spline curve; P i is the i-th control point; N i,p (u) is the basis function of the i-th p-th order B-spline curve with the i-th control point; i is the first ordinal parameter; p is the order parameter; u is the control point on the B-spline curve; and n is the total number of control points.

6. The axial positioning method for annular corrugated parts according to claim 5, characterized in that: The expression of the basis function of the B-spline curve is: Among them, N i,0 (u) is the basis function of the i-th 0th degree B-spline curve of the i-th control point; u i is the i-th control point on the B-spline curve.

7. The axial positioning method for annular corrugated parts according to claim 3, characterized in that: According to the B-spline curve of the generatrix of the annular wave-shaped part, a second-order difference recognition algorithm is used to obtain the generatrix profile of the annular wave-shaped part, including: According to the B-spline curve of the annular wave-shaped part busbar, a convolution calculation is performed based on a second-order difference operator, and feature extraction is performed to obtain edges and feature points on the B-spline curve; The edge curvature is analyzed according to the edge and the characteristic point to obtain the generatrix contour of the annular wavy part; wherein the generatrix contour of the annular wavy part includes a plurality of convex points and concave points, the convex points are the peak positions on the generatrix contour of the annular wavy part, and the concave points are the trough positions on the generatrix contour of the annular wavy part.

8. The axial positioning method for annular corrugated parts according to claim 7, characterized in that: The expression of the second-order difference identification algorithm is: f″(j)=f(j+1)-2f(j)+f(j-1); Wherein, f(j) is the gray value of the jth point on the B-spline curve; j is the first ordinal parameter; f″(j) is the second-order difference dispersion function of f(j); is a second-order difference operator; x is the first parameter; y is the second parameter; is the partial derivative function.

9. An axial positioning device for an annular corrugated part, characterized in that: Using the axial positioning method for annular wave-shaped parts as described in any one of claims 1 to 8, the axial positioning device includes: a distance measurement module and a data acquisition and processing module; The distance measuring module is used to respectively locate the highest point and the lowest point of the busbar of the annular corrugated part, and scan the annular corrugated part along the first direction to obtain the busbar position information of the annular corrugated part; The data acquisition and processing module is used to perform inverse fitting according to the busbar position information to obtain the busbar profile of the annular wave-shaped part.

10. An axial positioning system for annular corrugated parts, characterized in that: include: A processing machine tool and an axial positioning device for annular corrugated parts as claimed in claim 9; The distance measuring module is arranged on the motion module of the processing machine tool, and moves with the motion module of the processing machine tool to obtain the busbar position information of the annular wave-shaped part in real time through motion scanning.

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