An assembly method and apparatus based on contact surfaces

Abstract

This application provides an assembly method and apparatus based on contact surfaces. When assembling precision-machined parts, the method places a movable surface in a non-contact state at the initial assembly position of a fixed surface, determines a representative point of a convex peak region and a fixed representative point in the fixed surface; obtains any one of the convex peak regions to determine a first contact point; determines a second contact point based on the convex peak representative point and the first contact point; determines a third contact point by rotating the line connecting the target intersection point and the second contact point; checks whether the triangular region formed by the first, second, and third contact points meets the assembly conditions. If it does, a pose transformation matrix is ​​output to assemble the movable and fixed surfaces according to the pose transformation matrix; otherwise, the third contact point is eliminated according to a set elimination rule, and the third contact point is re-determined until the assembly conditions are met. Therefore, this application can meet the assembly requirements of precision-machined parts.

Description

Technical Field

[0001] This application relates to the field of precision mechanical assembly technology, and in particular to an assembly method and apparatus based on contact surfaces. Background Technology

[0002] Currently, existing virtual assembly methods all assemble parts according to their ideal dimensions. However, in practical applications, the actual surfaces of parts always contain geometric errors. For ordinary machining, these geometric errors are negligible because the assembly precision requirements are relatively low. This means that even virtual assembly using ideal dimensions can meet the corresponding assembly precision requirements during actual assembly. Therefore, for ordinary machining, the existence of geometric errors can be ignored. However, for precision-machined parts, whose surface morphology is composed of many peaks and valleys of different sizes and shapes at the microscopic level, determining the assembly position and orientation according to the ideal dimensions of the part will cause deviations from the ideal assembly position during actual assembly, resulting in poor assembly precision and difficulty in meeting assembly requirements.

[0003] Therefore, considering the geometric errors of the assembly surfaces of parts and calculating the assembly pose based on the actual point cloud data of the contact surfaces can more accurately represent the actual contact situation of physical entities. Summary of the Invention

[0004] In view of this, this application provides an assembly method, apparatus and equipment based on contact surfaces to meet the assembly requirements of precision machining.

[0005] Specifically, this application is implemented through the following technical solution:

[0006] In a first aspect, embodiments of this application provide an assembly method based on contact surfaces, the method comprising:

[0007] Obtain point cloud data of any pair of contact surfaces in a specified assembly, and specify a moving surface and a fixed surface from the pair of contact surfaces according to the assembly relationship of the pair of contact surfaces in the specified assembly, and place the moving surface at the initial assembly position of the fixed surface in a non-contact manner.

[0008] For each convex peak region in the moving surface, a representative point of the convex peak region is determined, and a fixed representative point corresponding to the convex peak region is determined from the fixed surface; wherein, the convex peak region is the region to which the convex peak belongs in the moving surface;

[0009] Obtain any of the convex peak regions from the convex peak regions, and determine whether the convex peak representative point corresponding to the convex peak region and the fixed representative point of the surface region corresponding to the convex peak region are in point contact. If they are in point contact, then determine the pair of contact points between the moving surface and the fixed surface as the first contact point; otherwise, return to the step of obtaining any of the convex peak regions from the convex peak regions.

[0010] The rotation axis is determined based on the representative point of the convex peak and the first contact point. For each convex peak region in the moving surface, the rotation axis is rotated according to a set step size. The second contact point is determined based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region.

[0011] The target intersection point is rotated around the line connecting the target intersection point and the second contact point. For each convex peak region in the moving surface, the third contact point is determined based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region. The target intersection point is the intersection point obtained by drawing a perpendicular line from the center of gravity of the moving surface to the line connecting the first contact point and the second contact point.

[0012] Check whether the triangular region formed by the first contact point, the second contact point, and the third contact point can meet the set assembly conditions. If it can, output the pose transformation matrix corresponding to the first contact point, the second contact point, and the third contact point respectively, so as to assemble the moving surface and the fixed surface according to the pose transformation matrix; otherwise, eliminate the third contact point according to the set elimination rule, and return to the step of rotating the line connecting the target intersection point and the second contact point until the three finally determined contact points meet the assembly conditions. The elimination rule is as follows: connect any two of the three contact points. If the center of gravity and the unconnected contact point are on opposite sides of the line, the unconnected contact point is eliminated. If the center of gravity and the unconnected contact point are on the same side of the line, the unconnected contact point is retained.

[0013] As one embodiment, the method for determining the representative point of the convex peak region includes:

[0014] The convex peak region is gridded to obtain gridded points;

[0015] From the convex peak region, select the first preset number of gridded points in the convex peak region that are closest to the fixed surface as convex peak points, and determine the average value of the coordinates of each convex peak point in the convex peak region as the representative point of the convex peak.

[0016] As one embodiment, determining the fixed representative point corresponding to the convex peak region from the fixed surface includes:

[0017] The fixed surface is meshed to obtain mesh points;

[0018] For each surface region in the fixed surface that corresponds to the convex peak region, a preset number of gridded points that are closest to the convex peak region are selected from the surface region as fixed points; and the average value of the coordinates of each fixed point in the surface region is determined as a fixed representative point.

[0019] As one embodiment, determining whether the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region are in point contact includes:

[0020] Calculate the point distances between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region, and determine the minimum point distance;

[0021] Move the moving surface a minimum distance along the center line of the fixed surface, and after moving the minimum distance, determine whether there is point contact between the moving surface and the fixed surface.

[0022] As one embodiment, determining the rotation axis based on the representative point of the convex peak and the first contact point includes:

[0023] The center of gravity of the moving surface is determined based on the representative point of the convex peak, and the line connecting the center point and the center of gravity is established as the axis of rotation, with the first contact point as the center.

[0024] The process of rotating the axis according to a set step size, and determining the second contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region, includes:

[0025] The moving surface is driven along the rotation axis to rotate once in a direction closer to the fixed surface with a specified step size. After completing one rotation, the steps of determining the representative point of the convex peak region and determining the fixed representative point corresponding to the convex peak region from the fixed surface are performed.

[0026] Obtain any of the convex peak regions, calculate the point distance between the representative point of the convex peak corresponding to the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region; if the calculated point distance difference is negative, then determine the representative point of the convex peak corresponding to the point distance as the second contact point; if the calculated point distance difference is positive, then return to the step of rotating the moving surface along the rotation axis towards the fixed surface once according to the specified step size.

[0027] As one embodiment, rotating the line connecting the target intersection point and the second contact point includes:

[0028] The moving surface is rotated once around the line connecting the target intersection point and the second contact point, driven by the center of gravity, in a direction closer to the fixed surface, according to a set step size;

[0029] After completing one rotation, determining the third contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region includes:

[0030] Perform the steps of determining the representative point of the convex peak region and determining the fixed representative point corresponding to the convex peak region from the fixed surface; and for each convex peak region in the moving surface, obtain any convex peak region from the convex peak region, calculate the point distance between the representative point of the convex peak region and the fixed representative point of the surface region corresponding to the convex peak region. If the calculated point distance difference is negative, then the convex peak representative point corresponding to the point distance is determined as the third contact point; if the calculated point distance difference is positive, then return to the step of rotating the moving surface once along the direction of the line connecting the target intersection point and the second contact point according to the set step size.

[0031] As one embodiment, checking whether the triangular region formed by the first contact point, the second contact point, and the third contact point can meet the set assembly conditions includes:

[0032] Check whether the triangular region formed by the first contact point, the second contact point, and the third contact point can surround the center of gravity. If so, execute the step of outputting the pose transformation matrix corresponding to the first contact point, the second contact point, and the third contact point respectively. Otherwise, eliminate the third contact point according to the set elimination rules, and return to execute the step of rotating the line connecting the target intersection point and the second contact point until the three finally determined contact points can surround the center of gravity.

[0033] Secondly, embodiments of this application provide an assembly device based on a contact surface, the device comprising:

[0034] An initial position determination unit is used to obtain point cloud data of any pair of contact surfaces in a specified assembly, and, based on the assembly relationship of the pair of contact surfaces in the specified assembly, to designate a moving surface and a fixed surface from the pair of contact surfaces, and to place the moving surface at the initial assembly position of the fixed surface in a non-contact manner.

[0035] The representative point determination unit is used to determine a representative point of the peak for each peak region in the moving surface, and to determine a fixed representative point corresponding to the peak region from the fixed surface; wherein, the peak region is the region to which the peak belongs in the moving surface;

[0036] The first contact point determination unit is used to obtain any of the convex peak regions from the convex peak regions, determine whether the convex peak representative point corresponding to the convex peak region and the fixed representative point of the surface region corresponding to the convex peak region are in point contact, and if they are in point contact, determine a pair of contact points between the moving surface and the fixed surface as the first contact point; otherwise, return to the step of obtaining any of the convex peak regions from the convex peak regions.

[0037] The second contact point determination unit is used to determine the rotation axis based on the convex peak representative point and the first contact point, and to rotate the rotation axis according to a set step size for each convex peak region in the moving surface, and to determine the second contact point based on the rotation result and the point distance between the convex peak representative point corresponding to the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region.

[0038] The third contact point determination unit is used to rotate around the line connecting the target intersection point and the second contact point, and for each convex peak region in the moving surface, determine the third contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region; wherein, the target intersection point is the intersection point obtained by drawing a perpendicular line from the center of gravity of the moving surface to the line connecting the first contact point and the second contact point;

[0039] An assembly pose output unit is used to check whether the triangular region formed by the first contact point, the second contact point, and the third contact point can surround the center of gravity. If so, the pose transformation matrix corresponding to the first contact point, the second contact point, and the third contact point is output to assemble the moving surface and the fixed surface according to the pose transformation matrix. Otherwise, the third contact point is eliminated according to the set elimination rule, and the step of rotating the line connecting the target intersection point and the second contact point is returned to be executed until the three finally determined contact points can surround the center of gravity. The elimination rule is as follows: when any two of the three contact points are connected, if the center of gravity and the unconnected contact point are on opposite sides of the line, the unconnected contact point is eliminated; if the center of gravity and the unconnected contact point are on the same side of the line, the unconnected contact point is retained.

[0040] As one embodiment, the representative point determination unit includes a convex peak representative point determination subunit for determining the convex peak representative point of the convex peak region, wherein the convex peak representative point determination subunit is specifically used for:

[0041] The convex peak region is gridded to obtain gridded points;

[0042] From the convex peak region, select the first preset number of gridded points in the convex peak region that are closest to the fixed surface as convex peak points, and determine the average value of the coordinates of each convex peak point in the convex peak region as the representative point of the convex peak.

[0043] As one embodiment, the representative point determination unit further includes a fixed representative point subunit for determining a fixed representative point corresponding to the convex peak region from a fixed surface, wherein the fixed representative point subunit is specifically used for:

[0044] The fixed surface is meshed to obtain mesh points;

[0045] For each surface region in the fixed surface that corresponds to the convex peak region, a preset number of gridded points that are closest to the convex peak region are selected from the surface region as fixed points; and the average value of the coordinates of each fixed point in the surface region is determined as a fixed representative point.

[0046] Therefore, this application provides an assembly method based on contact surfaces. When assembling precision-machined parts, this method designates a moving surface and a fixed surface from any pair of contact surfaces of a specified assembly. The moving surface is placed in a non-contact state at the initial assembly position of the fixed surface. For each convex region in the moving surface, a representative point of the convex region is determined, and a corresponding fixed representative point is determined from the fixed surface. Any convex region is obtained from the convex regions. When the representative point of the convex region and the fixed representative point of the corresponding surface region are in point contact, the pair of contact points between the moving surface and the fixed surface are determined as the first contact point. Then, a rotation axis is determined based on the representative point and the first contact point, and the rotation axis is rotated according to a set step size. The second contact point is determined based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region. The system rotates around the line connecting the target intersection point and the second contact point, and the third contact point is determined based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region. The system checks whether the triangular region formed by the first, second, and third contact points meets the assembly conditions. If so, the system outputs the pose transformation matrices corresponding to the first, second, and third contact points to assemble the moving and fixed surfaces according to the pose transformation matrices. Otherwise, the third contact point is eliminated according to the set elimination rules, and the third contact point is re-determined until the three finally determined contact points meet the assembly conditions. Therefore, the technical solution provided in this application considers the geometric errors of the part assembly surface and performs assembly pose calculations based on the actual point cloud data of the contact surface. It iteratively transforms the contact pose of the point cloud data on the surface of the assembly area until the final three-point contact point cloud pose of the assembly area that meets the assembly conditions is found. The technical solutions provided by the embodiments of this application can accurately reflect the actual assembly situation and provide effective guidance for actual assembly to meet the assembly requirements of precision machining, thereby improving assembly accuracy. Attached Figure Description

[0047] Figure 1 This is a flowchart illustrating an assembly method in an exemplary embodiment of this application;

[0048] Figure 2(a) is a schematic diagram of the positional relationship of the plane fitting surface with error, as shown in an exemplary embodiment of this application;

[0049] Figure 2(b) is a schematic diagram illustrating the positional relationship of the fitting axis of the arc surface with error in an exemplary embodiment of this application;

[0050] Figure 3(a) is a schematic diagram of the initial position point cloud of the moving surface and the fixed surface shown in an exemplary embodiment of this application;

[0051] Figure 3(b) is a schematic diagram of the convex peak representative points after the moving surface and the fixed surface are meshed according to an exemplary embodiment of this application;

[0052] Figure 4(a) is a schematic diagram illustrating the determination of the second contact point in an exemplary embodiment of this application;

[0053] Figure 4(b) is a schematic diagram illustrating the determination of a third contact point in an exemplary embodiment of this application;

[0054] Figure 5 This is a schematic diagram of the structure of an assembly device shown in an exemplary embodiment of this application;

[0055] Figure 6 This is a schematic diagram of the structure of an electronic device provided in this application. Detailed Implementation

[0056] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0057] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0058] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0059] See Figure 1 , Figure 1 This is a flowchart illustrating an assembly method based on contact surfaces according to an embodiment of this application. The method includes the following steps:

[0060] Step 101: Obtain point cloud data of any pair of contact surfaces in the specified assembly, and specify a moving surface and a fixed surface from the pair of contact surfaces according to the assembly relationship of the pair of contact surfaces in the specified assembly, and place the moving surface at the initial assembly position of the fixed surface in a non-contact manner.

[0061] In this embodiment, the point cloud data of any pair of contact surfaces in the specified assembly can come from the corresponding point cloud data stored locally, or it can be obtained from other electronic devices, or it can be point cloud data input by the user after actual measurement. This embodiment does not limit this.

[0062] The point cloud data obtained above can be obtained after preprocessing. In some embodiments, preprocessing operations are performed on the point cloud data of the contact surface, such as filtering and noise reduction.

[0063] The initial assembly position in this step can be understood as placing the two point cloud data at the coarse registration position before contact.

[0064] In this embodiment, the two contact surfaces can be arbitrarily designated as a moving surface and a fixed surface. For example, if a pair of contact surfaces are surface A and surface B, when surface A is designated as a moving surface, then surface B is a fixed surface. When surface A is designated as a fixed surface, then surface B is a moving surface.

[0065] Step 102: For each convex peak region in the moving surface, determine the representative point of the convex peak region, and determine the fixed representative point corresponding to the convex peak region from the fixed surface.

[0066] The convex peak region is the region to which the convex peak belongs in the moving surface.

[0067] In this step, the moving surface is actually composed of convex peaks and grooves. In other words, the moving surface may have at least one convex peak, and the convex peak area can be understood as the area where the convex peak is located.

[0068] A convex peak representative point can be understood as a point that can be used to represent a convex peak within a convex peak region. A fixed representative point can be understood as a representative point in the surface region corresponding to the convex peak region within a fixed surface.

[0069] Step 103: Obtain any convex peak region from the convex peak region, and determine whether the convex peak representative point corresponding to the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region are in point contact. If they are in point contact, determine the pair of contact points of the moving surface and the fixed surface as the first contact point; otherwise, return to the step of obtaining any convex peak region from the convex peak region.

[0070] In this embodiment, the first contact point is named only to distinguish it from the contact points mentioned later, and is not used to limit a specific contact point.

[0071] The first contact point can be understood as the point where the moving surface and the contact surface make contact at the first moment.

[0072] In some embodiments, the Euclidean distance difference between the corresponding point cloud data of the meshed contact surface can be calculated, and the smallest distance difference can be found as the translation distance of the first translation matrix. After translating the surface, the first contact point is obtained. This will be described in detail later and will not be repeated here.

[0073] Step 104: Determine the rotation axis based on the representative point of the convex peak and the first contact point, and rotate the rotation axis according to a set step size for each convex peak region in the moving surface. Determine the second contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region.

[0074] The second contact point is named simply to distinguish it from other contact points, and is not intended to define a specific contact point.

[0075] This step rotates the axis according to the set step size. During each rotation, the two contact surfaces are re-meshed and points are taken. The second contact point is determined based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region.

[0076] Step 105: Rotate around the line connecting the target intersection point and the second contact point, and for each convex peak region in the moving surface, determine the third contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region.

[0077] The target intersection point is the intersection point obtained by drawing a perpendicular line from the center of gravity of the moving surface to the line connecting the first contact point and the second contact point.

[0078] The name "third contact point" is merely for the purpose of distinguishing it from other contact points, and is not intended to define a specific contact point.

[0079] In this embodiment, the coordinates of the center of gravity of the moving surface are first determined. A perpendicular line is drawn from the center of gravity of the moving surface to the line connecting the two contact points. The intersection of the two lines is taken as the center of the circle. The moving surface is rotated around the line connecting the second contact points with the center of gravity in the direction closer to the fixed surface according to the set step size. During each rotation, the two contact surfaces are meshed and points are taken respectively. The Euclidean distance difference between the corresponding points in step 103 is calculated until the third contact point appears.

[0080] Step 106: Check whether the triangular region formed by the first contact point, the second contact point, and the third contact point can meet the set assembly conditions. If yes, output the pose transformation matrix corresponding to the first contact point, the second contact point, and the third contact point respectively, so as to assemble the moving surface and the fixed surface according to the pose transformation matrix; otherwise, eliminate the third contact point according to the set elimination rules, return to step 105, until the three finally determined contact points meet the assembly conditions.

[0081] The elimination rule is as follows: connect any two of the three contact points. If the center of gravity and the unconnected contact point are on opposite sides of the connecting line, the unconnected contact point is eliminated. If the center of gravity and the unconnected contact point are on the same side of the connecting line, the unconnected contact point is retained.

[0082] In some embodiments, the assembly conditions may be that the center of gravity is surrounded by a triangular region formed by the first contact point, the second contact point, and the third contact point.

[0083] In this embodiment, if the assembly conditions are met, the pose transformation matrices corresponding to the first contact point, the second contact point, and the third contact point are output. The moving surface and the fixed surface can be assembled according to the pose transformation matrices, so that the accuracy of the assembled moving surface and the fixed surface is higher.

[0084] In this embodiment, the third contact point is the outer point. This step checks whether the triangular area formed by the three contact points can surround the center point. If it can, the final pose transformation matrix and contact point coordinates are output. If not, the outer point, i.e. the third contact point, is removed, and step 105 is repeated. The process is iteratively optimized until the new three contact points can surround the center point.

[0085] As can be seen, the technical solution provided in this embodiment finds the three-point contact point cloud pose of the assembly area that can meet the assembly conditions by continuously iterating and transforming the contact pose of the contact surface point cloud data. Compared with traditional simulation solutions, it is more efficient, suitable for a large number of selection and assembly processes, and can also guarantee high accuracy.

[0086] This concludes the process. Figure 1 The description shown.

[0087] Therefore, in the technical solution of this application embodiment, when assembling precision machined parts, the method specifies a moving surface and a fixed surface from any pair of contact surfaces of a specified assembly, and places the moving surface in a non-contact state at the initial assembly position of the fixed surface. For each convex region in the moving surface, a representative point of the convex region is determined, and a fixed representative point corresponding to the convex region is determined from the fixed surface. Any convex region is obtained from the convex region. When the representative point of the convex region and the fixed representative point of the corresponding surface region are in point contact, the pair of contact points between the moving surface and the fixed surface are determined as the first contact point. Then, a rotation axis is determined based on the representative point and the first contact point, and the rotation axis is rotated according to a set step size. The second contact point is determined by the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region. The second contact point is then rotated around the line connecting the target intersection point and the second contact point, and the third contact point is determined based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region. The triangular region formed by the first, second, and third contact points is checked to see if it meets the assembly conditions. If it does, the pose transformation matrices corresponding to the first, second, and third contact points are output to assemble the moving and fixed surfaces according to the pose transformation matrices. Otherwise, the third contact point is eliminated according to the set elimination rules, and the third contact point is re-determined until the three finally determined contact points meet the assembly conditions. It is evident that the technical solution provided in this application considers the geometric errors of the part assembly surface and performs assembly pose calculations based on the actual point cloud data of the contact surface. By continuously iterating and transforming the contact pose of the point cloud data on the surface of the assembly area, the final three-point contact point cloud pose of the assembly area that meets the assembly conditions is found. The technical solutions provided by the embodiments of this application can accurately reflect the actual assembly situation and provide effective guidance for actual assembly to meet the assembly requirements of precision machining, thereby improving assembly accuracy.

[0088] Finish Figure 1 Following the steps shown, as an example, the implementation of determining the representative point of the convex peak region in step 102 may include:

[0089] Step A1: Mesh the convex peak region to obtain mesh points.

[0090] This embodiment performs gridded point sampling on the moving surface, dividing the entire point cloud data into gridded point cloud data of different regions according to a certain coordinate logic, in order to simplify the point cloud data. For example, for a shaft-hole mating body, the point cloud data of the shaft, which is the moving surface in the shaft-hole mating surface, can be divided into grids according to the height direction.

[0091] Step A2: Obtain the first preset number of gridded points in the convex peak region that are closest to the fixed surface as convex peak points, and determine the average value of the coordinates of each convex peak point in the convex peak region as the representative point of the convex peak.

[0092] For the point cloud data within the grid, the Euclidean distance from the central axis is used as the screening standard to select the first set number of gridded representative points with the largest Euclidean distance (the inner point cloud data is the largest, and the outer point cloud data is the smallest) as convex peak points. Then, the average coordinate of these convex peak points is taken as the convex peak representative point.

[0093] Since each pose change causes a change in the point coordinates, the meshing process is repeated with each position change to ensure the reasonableness of the peaks representing the points.

[0094] As shown in Figure 2(a), M is the moving surface, N is the fixed surface, and R is the fixed fitting surface. When solving for the contact point target as a planar contact with errors, firstly, plane fitting is performed on N to obtain the fitting plane equation of N, and the plane is translated to a suitable position. When calculating the coordinates of the gridded representative points within the M grid, the distance from the points within the grid to R is used as the screening standard. A specified number of points within a first distance threshold range are selected as representative points, and the average value is calculated as the coordinates of the representative points of that grid. The same applies to N, but points within a second distance threshold range should be selected as representative points.

[0095] As shown in Figure 2(b), M is the moving surface, N is the fixed surface, and R is the arc fitting axis of the fixed surface. When solving for the contact point target as an arc surface contact with errors, N is first fitted with an arc to obtain the expression for the central axis. When calculating the coordinates of the gridded representative points within the M grid, the distance from the points within the grid to R is used as the screening standard. A specified number of points within the first distance threshold range are selected as representative points, and the average value is calculated as the coordinates of the representative points of that grid. N is treated similarly, but points within the second distance threshold range should be selected as representative points.

[0096] The aforementioned first distance threshold range is as follows: sort the points in the grid from largest to smallest according to their distance to R, and select the distance range of the first specified number of points as the first distance threshold range.

[0097] The second distance threshold range is defined as follows: sort the points in the grid according to their distance to R from smallest to largest, and select the distance range of the first specified number of points as the second distance threshold range.

[0098] The first distance threshold range is named simply to distinguish it from the distance threshold ranges mentioned later, and is not intended to define a specific distance threshold range.

[0099] Similarly, the second distance threshold range is named only to distinguish it from the distance threshold range mentioned later, and is not used to define a specific distance threshold range.

[0100] As another embodiment, the method for determining the fixed representative point corresponding to the convex peak region from the fixed surface in step 102 includes the following steps:

[0101] Step B1: Mesh the fixed surface to obtain mesh points.

[0102] This embodiment performs gridded point sampling on the fixed surface, dividing the entire point cloud data into gridded point cloud data of different regions according to a certain coordinate logic, in order to simplify the point cloud data. For example, for a shaft-hole mating body, the point cloud data of the hole, which is a fixed surface in the shaft-hole mating surface, can be divided into grids according to the radius direction.

[0103] Step B2: For each surface region in the fixed surface corresponding to the convex peak region, select the first preset number of gridded points that are closest to the convex peak region from the surface region as fixed points; and determine the average value of the coordinates of each fixed point in the surface region as a fixed representative point.

[0104] For the point cloud data within the grid, the Euclidean distance from the central axis is used as the screening standard. A preset number of fixed points with the largest Euclidean distance (maximum for inner points and minimum for outer points) are selected, such as 20. The average coordinates of these fixed points are then used as fixed representative points, as shown in Figure 3. In Figure 3(a), M is the moving surface and N is the fixed surface. In Figure 3(b), M and N are the convex peak representative points after the moving and fixed surfaces are meshed, respectively. Since the point coordinates change with each pose transformation, the meshing process is repeated for each position transformation to ensure the rationality of the representative points.

[0105] As can be seen, when dealing with complex curved surface contact problems with large and dense point cloud data, this embodiment simplifies the dense point cloud data by meshing, and because the meshing continuously re-selects representative points during the rotation process, it can also retain the positional accuracy of the original point cloud data.

[0106] In some embodiments, the method for determining whether the representative point of the convex peak region corresponding to the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region are in point contact in step 104 includes the following steps:

[0107] Step C1: Calculate the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region, and determine the minimum point distance.

[0108] The point distance in this step is calculated by measuring the Euclidean distance difference between corresponding points in the point cloud of the contact surface after meshing. Determining the minimum point distance means finding the minimum distance difference as the translation distance of the first translation matrix. After translating the surface, the first contact point is obtained.

[0109] Step C2: Move the moving surface a minimum distance along the center line of the fixed surface. After moving the minimum distance, determine whether there is point contact between the moving surface and the fixed surface.

[0110] If the moving surface and the fixed surface make contact after moving the minimum point distance, it means that the first contact point has been found. If they do not make contact, the mesh is re-divided and points are taken to determine the representative point of the convex peak and the fixed representative point. The point distance is recalculated according to steps C1 to C2 to determine the first contact point.

[0111] In some embodiments, the method of determining the rotation axis based on the convex peak representative point and the first contact point in step 104 includes the following steps:

[0112] Step D1: Determine the center of gravity of the moving surface based on the representative point of the convex peak, and establish the line connecting the center point and the center of gravity as the axis of rotation, with the first contact point as the center.

[0113] To facilitate understanding of this step, please refer to Figure 4(a). In Figure 4(a), P1 is the first contact point, Z is the center of gravity of the moving surface, and the axis of rotation is AXIS1, which is the line connecting P1 and Z.

[0114] Based on the above embodiments, the implementation method of rotating the rotation axis according to a set step size in step 104, and determining the second contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region, includes the following steps:

[0115] Step D2: Rotate the moving surface along the rotation axis toward the fixed surface by a specified step size. After completing one rotation, proceed to step 102.

[0116] Step D3: Obtain any of the convex peak regions from the convex peak regions, and calculate the point distance between the representative point of the convex peak corresponding to the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region; if the calculated point distance difference is negative, proceed to step D4; if the calculated point distance difference is positive, return to step D2.

[0117] Step D4: Determine the point at which the distance to the corresponding convex peak represents the second contact point.

[0118] In this embodiment, the coordinates of the center of gravity of the moving surface are first determined, and the coordinates of the center of gravity are connected with the first contact point. The surface is rotated in a direction closer to the reference surface with the center of gravity as the center, according to a set step size. During each rotation, the two contact surfaces are re-meshed and points are taken, and the Euclidean distance difference between the corresponding points in step D3 is calculated. A negative Euclidean distance difference is used as the contact judgment criterion until a second contact point appears.

[0119] In other embodiments, the rotation around the line connecting the target intersection point and the second contact point in step 105 is implemented in the following ways:

[0120] Step E1: The moving surface is rotated once around the line connecting the target intersection point and the second contact point, driven by the center of gravity, in a direction closer to the fixed surface, according to a set step length.

[0121] Referring to Figure 4(b), P1 is the first contact point, P2 is the second contact point, T is the target intersection point, Z is the center of gravity of the moving surface, and the rotation axis is AXIS2. In Figure 4(b), the moving surface rotates once around the line connecting T and P2, i.e. AXIS2, driven by the center of gravity, toward the direction closer to the fixed surface according to the set step size.

[0122] Based on the above embodiments, after completing one rotation, the method for determining the third contact point in step 105 based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region includes the following steps:

[0123] Step E2: Execute the steps of determining the representative point of the convex peak region and determining the fixed representative point corresponding to the convex peak region from the fixed surface; and for each convex peak region in the moving surface, obtain any convex peak region from the convex peak region, calculate the point distance between the representative point of the convex peak region and the fixed representative point of the surface region corresponding to the convex peak region. If the calculated point distance difference is negative, execute step E3; if the calculated point distance difference is positive, return to execute step E1.

[0124] Step E3: Determine the point at which the distance to the corresponding convex peak represents the third contact point.

[0125] In this embodiment, a perpendicular line is drawn from the center of gravity of the moving surface to the line connecting the two contact points. With the intersection of the two lines as the center, the surface is rotated around the line connecting the contact points in a direction closer to the fixed surface according to a set step size. During each rotation, the two contact surfaces are meshed and points are taken respectively, and the Euclidean distance difference between the corresponding points in step E2 is calculated until a third contact point appears.

[0126] As can be seen, this embodiment can solve most complex curved surface contact problems with errors. It only requires changing the corresponding meshing method according to the specific surface shape, and solving the corresponding contact points and pose transformation matrix through rotation matrix and displacement matrix transformation to obtain the final surface contact state.

[0127] As an example, step 106, which checks whether the triangular region formed by the first contact point, the second contact point, and the third contact point can meet the set assembly conditions, includes the following steps:

[0128] Step F1: Check whether the triangular region formed by the first contact point, the second contact point, and the third contact point can enclose the center of gravity; if yes, execute the step of outputting the pose transformation matrix corresponding to the first contact point, the second contact point, and the third contact point respectively; if no, execute step F2.

[0129] Step F2: Eliminate the third contact point according to the set elimination rules, and return to step E1 until the final three contact points can surround the center point.

[0130] In this embodiment, it is checked whether the triangular region formed by the three extracted contact points can surround the center of gravity. If it can, the final pose transformation matrix and contact point coordinates are output to assemble the moving surface and the fixed surface according to the output pose transformation matrix. If not, the outer point, i.e., the third contact point, is removed, and step 105 is repeated iteratively until the new three contact points can surround the center of gravity, i.e., the assembly conditions are met.

[0131] See Figure 5 This application provides a schematic diagram of the structure of an assembly device 300 based on a contact surface, the device comprising:

[0132] The initial position determination unit 301 is used to obtain point cloud data of any pair of contact surfaces in a specified assembly, and, according to the assembly relationship of the pair of contact surfaces in the specified assembly, to specify a moving surface and a fixed surface from the pair of contact surfaces, and to place the moving surface at the initial assembly position of the fixed surface in a non-contact manner.

[0133] The representative point determination unit 302 is used to determine a representative point of the peak for each peak region in the moving surface, and to determine a fixed representative point corresponding to the peak region from the fixed surface; wherein, the peak region is the region to which the peak belongs in the moving surface;

[0134] The first contact point determination unit 303 is used to obtain any of the convex peak regions from the convex peak regions, determine whether the convex peak representative point corresponding to the convex peak region and the fixed representative point of the surface region corresponding to the convex peak region are in point contact, and if they are in point contact, determine a pair of contact points between the moving surface and the fixed surface as the first contact point; otherwise, return to the step of obtaining any of the convex peak regions from the convex peak regions.

[0135] The second contact point determination unit 304 is used to determine the rotation axis based on the convex peak representative point and the first contact point, and rotate the rotation axis according to a set step size for each convex peak region in the moving surface, and determine the second contact point based on the rotation result and the point distance between the convex peak representative point corresponding to the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region.

[0136] The third contact point determination unit 305 is used to rotate around the line connecting the target intersection point and the second contact point, and for each convex peak region in the moving surface, determine the third contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region; wherein, the target intersection point is the intersection point obtained by drawing a perpendicular line from the center of gravity of the moving surface to the line connecting the first contact point and the second contact point;

[0137] The assembly pose output unit 306 is used to check whether the triangular region formed by the first contact point, the second contact point, and the third contact point can surround the center of gravity. If it can, the pose transformation matrix corresponding to the first contact point, the second contact point, and the third contact point is output to assemble the moving surface and the fixed surface according to the pose transformation matrix. Otherwise, the third contact point is eliminated according to the set elimination rule, and the step of rotating the line connecting the target intersection point and the second contact point is returned to be executed until the three finally determined contact points can surround the center of gravity. The elimination rule is as follows: when any two of the three contact points are connected, if the center of gravity and the unconnected contact point are on opposite sides of the line, the unconnected contact point is eliminated. If the center of gravity and the unconnected contact point are on the same side of the line, the unconnected contact point is retained.

[0138] As one embodiment, the representative point determination unit 302 includes a convex peak representative point determination subunit for determining the convex peak representative point of the convex peak region, the convex peak representative point determination subunit being specifically used for:

[0139] The convex peak region is gridded to obtain gridded points;

[0140] From the convex peak region, select the first preset number of gridded points in the convex peak region that are closest to the fixed surface as convex peak points, and determine the average value of the coordinates of each convex peak point in the convex peak region as the representative point of the convex peak.

[0141] As one embodiment, the representative point determination unit 302 further includes a fixed representative point subunit for determining a fixed representative point corresponding to the convex peak region from the fixed surface, wherein the fixed representative point subunit is specifically used for:

[0142] The fixed surface is meshed to obtain mesh points;

[0143] For each surface region in the fixed surface that corresponds to the convex peak region, a preset number of gridded points that are closest to the convex peak region are selected from the surface region as fixed points; and the average value of the coordinates of each fixed point in the surface region is determined as a fixed representative point.

[0144] As one embodiment, the first contact point determination unit 303 includes a point contact determination subunit for determining whether a representative point of the convex peak region corresponding to the convex peak region and a fixed representative point of the surface region corresponding to the convex peak region are in point contact. Specifically, the point contact determination subunit is used for:

[0145] Calculate the point distances between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region, and determine the minimum point distance;

[0146] Move the moving surface a minimum distance along the center line of the fixed surface, and after moving the minimum distance, determine whether there is point contact between the moving surface and the fixed surface.

[0147] As one embodiment, the second contact point determination unit 304 includes a rotation axis determination subunit for determining the rotation axis based on the convex peak representative point and the first contact point. Specifically, the rotation axis determination subunit is used for:

[0148] The center of gravity of the moving surface is determined based on the representative point of the convex peak, and the line connecting the center point and the center of gravity is established as the axis of rotation, with the first contact point as the center.

[0149] The process of rotating the axis according to a set step size, and determining the second contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region, includes:

[0150] The moving surface is rotated once along the rotation axis towards the fixed surface by a specified step size. After completing one rotation, the steps of determining the representative point of the convex peak region and determining the fixed representative point corresponding to the convex peak region from the fixed surface are executed.

[0151] Obtain any of the convex peak regions, calculate the point distance between the representative point of the convex peak corresponding to the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region; if the calculated point distance difference is negative, then determine the representative point of the convex peak corresponding to the point distance as the second contact point; if the calculated point distance difference is positive, then return to the step of rotating the moving surface along the rotation axis towards the fixed surface once according to the specified step size.

[0152] As one embodiment, the third contact point determination unit 305 includes a rotating subunit for rotating about the line connecting the target intersection point and the second contact point, the rotating subunit being specifically used for:

[0153] The moving surface is rotated once along the direction of the line connecting the target intersection point and the second contact point by a set step size;

[0154] After completing one rotation, determining the third contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region includes:

[0155] Perform the steps of determining the representative point of the convex peak region and determining the fixed representative point corresponding to the convex peak region from the fixed surface; and for each convex peak region in the moving surface, obtain any convex peak region from the convex peak region, calculate the point distance between the representative point of the convex peak region and the fixed representative point of the surface region corresponding to the convex peak region. If the calculated point distance difference is negative, then the convex peak representative point corresponding to the point distance is determined as the third contact point; if the calculated point distance difference is positive, then return to the step of rotating the moving surface once along the direction of the line connecting the target intersection point and the second contact point according to the set step size.

[0156] As one embodiment, the assembly pose output unit 306 includes a checking subunit for checking whether the triangular region formed by the first contact point, the second contact point, and the third contact point can meet the set assembly conditions. Specifically, the checking subunit is used for:

[0157] Check whether the triangular region formed by the first contact point, the second contact point, and the third contact point can surround the center of gravity. If so, execute the step of outputting the pose transformation matrix corresponding to the first contact point, the second contact point, and the third contact point respectively. Otherwise, eliminate the third contact point according to the set elimination rules, and return to execute the step of rotating the line connecting the target intersection point and the second contact point until the three finally determined contact points can surround the center of gravity.

[0158] This concludes the process. Figure 5 The description shown.

[0159] Therefore, in the technical solution of this application embodiment, when assembling precision machined parts, the method specifies a moving surface and a fixed surface from any pair of contact surfaces of a specified assembly, and places the moving surface in a non-contact state at the initial assembly position of the fixed surface. For each convex region in the moving surface, a representative point of the convex region is determined, and a fixed representative point corresponding to the convex region is determined from the fixed surface. Any convex region is obtained from the convex region. When the representative point of the convex region and the fixed representative point of the corresponding surface region are in point contact, the pair of contact points between the moving surface and the fixed surface are determined as the first contact point. Then, a rotation axis is determined based on the representative point and the first contact point, and the rotation axis is rotated according to a set step size. The second contact point is determined by the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region. The second contact point is then rotated around the line connecting the target intersection point and the second contact point, and the third contact point is determined based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region. The triangular region formed by the first, second, and third contact points is checked to see if it meets the assembly conditions. If it does, the pose transformation matrices corresponding to the first, second, and third contact points are output to assemble the moving and fixed surfaces according to the pose transformation matrices. Otherwise, the third contact point is eliminated according to the set elimination rules, and the third contact point is re-determined until the three finally determined contact points meet the assembly conditions. It is evident that the technical solution provided in this application considers the geometric errors of the part assembly surface and performs assembly pose calculations based on the actual point cloud data of the contact surface. By continuously iterating and transforming the contact pose of the point cloud data on the surface of the assembly area, the final three-point contact point cloud pose of the assembly area that meets the assembly conditions is found. The technical solutions provided by the embodiments of this application can accurately reflect the actual assembly situation and provide effective guidance for actual assembly to meet the assembly requirements of precision machining, thereby improving assembly accuracy.

[0160] The specific implementation process of the functions and roles of each unit in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.

[0161] The electronic device provided in this application, from a hardware perspective, can be found in the hardware architecture diagram. Figure 6 As shown, it includes a machine-readable storage medium and a processor, wherein: the machine-readable storage medium stores machine-executable instructions that can be executed by the processor; the processor is used to execute the machine-executable instructions to implement the assembly operations disclosed in the above example.

[0162] The machine-readable storage medium provided in this application embodiment stores machine-executable instructions. When the machine-executable instructions are invoked and executed by a processor, the machine-executable instructions cause the processor to perform the assembly operation disclosed in the above example.

[0163] Here, a machine-readable storage medium can be any electronic, magnetic, optical, or other physical storage device that can contain or store information, such as executable instructions, data, etc. For example, a machine-readable storage medium can be: RAM (Random Access Memory), volatile memory, non-volatile memory, flash memory, storage drives (such as hard disk drives), solid-state drives, any type of storage disk (such as optical discs, DVDs, etc.), or similar storage media, or combinations thereof.

[0164] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer, which can take the form of a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email sending and receiving device, game console, tablet computer, wearable device, or any combination of these devices.

[0165] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0166] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, embodiments of this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0167] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0168] Furthermore, these computer program instructions can also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in the process. Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0169] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0170] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0171] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An assembly method based on contact surfaces, characterized in that, The method includes: Obtain point cloud data of any pair of contact surfaces in a specified assembly, and specify a moving surface and a fixed surface from the pair of contact surfaces according to the assembly relationship of the pair of contact surfaces in the specified assembly, and place the moving surface at the initial assembly position of the fixed surface in a non-contact manner. For each convex peak region in the moving surface, a representative point of the convex peak region is determined, and a fixed representative point corresponding to the convex peak region is determined from the fixed surface; wherein, the convex peak region is the region to which the convex peak belongs in the moving surface; Obtain any of the convex peak regions from the convex peak regions, and determine whether the convex peak representative point corresponding to the convex peak region and the fixed representative point of the surface region corresponding to the convex peak region are in point contact. If they are in point contact, then determine the pair of contact points between the moving surface and the fixed surface as the first contact point; otherwise, return to the step of obtaining any of the convex peak regions from the convex peak regions. The rotation axis is determined based on the representative point of the convex peak and the first contact point. For each convex peak region in the moving surface, the rotation axis is rotated according to a set step size. The second contact point is determined based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region. The target intersection point is rotated around the line connecting the target intersection point and the second contact point. For each convex peak region in the moving surface, the third contact point is determined based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region. The target intersection point is the intersection point obtained by drawing a perpendicular line from the center of gravity of the moving surface to the line connecting the first contact point and the second contact point. Check whether the triangular region formed by the first contact point, the second contact point, and the third contact point can meet the set assembly conditions. If it can, output the pose transformation matrix corresponding to the first contact point, the second contact point, and the third contact point respectively, so as to assemble the moving surface and the fixed surface according to the pose transformation matrix; otherwise, eliminate the third contact point according to the set elimination rule, and return to the step of rotating around the line connecting the target intersection point and the second contact point, until the three finally determined contact points meet the assembly conditions. The elimination rule is as follows: connect any two of the three contact points. If the center of gravity and the unconnected contact point are on opposite sides of the line, the unconnected contact point is eliminated. If the center of gravity and the unconnected contact point are on the same side of the line, the unconnected contact point is retained.

2. The assembly method according to claim 1, characterized in that, The method for determining the representative point of the convex peak region includes: The convex peak region is gridded to obtain gridded points; From the convex peak region, select the first preset number of gridded points in the convex peak region that are closest to the fixed surface as convex peak points, and determine the average value of the coordinates of each convex peak point in the convex peak region as the representative point of the convex peak.

3. The assembly method according to claim 2, characterized in that, Determining the fixed representative point corresponding to the convex peak region from the fixed surface includes: The fixed surface is meshed to obtain mesh points; For each surface region in the fixed surface that corresponds to the convex peak region, a preset number of gridded points that are closest to the convex peak region are selected from the surface region as fixed points; and the average value of the coordinates of each fixed point in the surface region is determined as a fixed representative point.

4. The assembly method according to claim 3, characterized in that, Determining whether the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region are in point contact includes: Calculate the point distances between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region, and determine the minimum point distance; Move the moving surface a minimum distance along the center line of the fixed surface, and after moving the minimum distance, determine whether there is point contact between the moving surface and the fixed surface.

5. The assembly method according to claim 3, characterized in that, Determining the rotation axis based on the representative point of the convex peak and the first contact point includes: The center of gravity of the moving surface is determined based on the representative point of the convex peak, and the line connecting the center point and the center of gravity is established as the axis of rotation, with the first contact point as the center. The process of rotating the axis according to a set step size, and determining the second contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region, includes: The moving surface is driven along the rotation axis to rotate once in a direction closer to the fixed surface with a specified step size. After completing one rotation, the steps of determining the representative point of the convex peak region and determining the fixed representative point corresponding to the convex peak region from the fixed surface are performed. Obtain any of the convex peak regions, calculate the point distance between the representative point of the convex peak corresponding to the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region; if the calculated point distance difference is negative, then determine the representative point of the convex peak corresponding to the point distance as the second contact point; if the calculated point distance difference is positive, then return to the step of rotating the moving surface along the rotation axis with the center of gravity towards the fixed surface by a specified step size.

6. The assembly method according to claim 3, characterized in that, The rotation around the line connecting the target intersection point and the second contact point includes: The moving surface is rotated once around the line connecting the target intersection point and the second contact point, driven by the center of gravity, in a direction closer to the fixed surface, according to a set step size. After completing one rotation, determining the third contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region includes: Perform the steps of determining the representative point of the convex peak region and determining the fixed representative point corresponding to the convex peak region from the fixed surface; and for each convex peak region in the moving surface, obtain any convex peak region from the convex peak region, calculate the point distance between the representative point of the convex peak region and the fixed representative point of the surface region corresponding to the convex peak region. If the calculated point distance difference is negative, then the convex peak representative point corresponding to the point distance is determined as the third contact point; if the calculated point distance difference is positive, then return to the step of rotating the moving surface once along the direction of the line connecting the target intersection point and the second contact point according to the set step size.

7. The assembly method according to claim 6, characterized in that, The check to see if the triangular region formed by the first contact point, the second contact point, and the third contact point meets the set assembly conditions includes: Check whether the triangular region formed by the first contact point, the second contact point, and the third contact point can surround the center of gravity. If so, execute the step of outputting the pose transformation matrix corresponding to the first contact point, the second contact point, and the third contact point respectively. Otherwise, eliminate the third contact point according to the set elimination rules, and return to execute the step of rotating the line connecting the target intersection point and the second contact point until the three finally determined contact points can surround the center of gravity.

8. An assembly device based on a contact surface, characterized in that, The device includes: An initial position determination unit is used to obtain point cloud data of any pair of contact surfaces in a specified assembly, and, based on the assembly relationship of the pair of contact surfaces in the specified assembly, to designate a moving surface and a fixed surface from the pair of contact surfaces, and to place the moving surface at the initial assembly position of the fixed surface in a non-contact manner. The representative point determination unit is used to determine a representative point of the peak for each peak region in the moving surface, and to determine a fixed representative point corresponding to the peak region from the fixed surface; wherein, the peak region is the region to which the peak belongs in the moving surface; The first contact point determination unit is used to obtain any of the convex peak regions from the convex peak regions, determine whether the convex peak representative point corresponding to the convex peak region and the fixed representative point of the surface region corresponding to the convex peak region are in point contact, and if they are in point contact, determine a pair of contact points between the moving surface and the fixed surface as the first contact point; otherwise, return to the step of obtaining any of the convex peak regions from the convex peak regions. The second contact point determination unit is used to determine the rotation axis based on the convex peak representative point and the first contact point, and to rotate the rotation axis according to a set step size for each convex peak region in the moving surface, and to determine the second contact point based on the rotation result and the point distance between the convex peak representative point corresponding to the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region. The third contact point determination unit is used to rotate around the line connecting the target intersection point and the second contact point, and for each convex peak region in the moving surface, determine the third contact point based on the rotation result and the point distance between the representative point of the convex peak region and the fixed representative point of the corresponding surface region of the convex peak region; wherein, the target intersection point is the intersection point obtained by drawing a perpendicular line from the center of gravity of the moving surface to the line connecting the first contact point and the second contact point; An assembly pose output unit is used to check whether the triangular region formed by the first contact point, the second contact point, and the third contact point can surround the center of gravity. If so, the pose transformation matrix corresponding to the first contact point, the second contact point, and the third contact point is output to assemble the moving surface and the fixed surface according to the pose transformation matrix. Otherwise, the third contact point is eliminated according to the set elimination rule, and the step of rotating the line connecting the target intersection point and the second contact point is returned to be executed until the three finally determined contact points can surround the center of gravity. The elimination rule is as follows: when any two of the three contact points are connected, if the center of gravity and the unconnected contact point are on opposite sides of the line, the unconnected contact point is eliminated; if the center of gravity and the unconnected contact point are on the same side of the line, the unconnected contact point is retained.

9. The assembly device according to claim 8, characterized in that, The representative point determination unit includes a peak representative point determination subunit for determining peak representative points of the peak region, wherein the peak representative point determination subunit is specifically used for: The convex peak region is gridded to obtain gridded points; From the convex peak region, select the first preset number of gridded points in the convex peak region that are closest to the fixed surface as convex peak points, and determine the average value of the coordinates of each convex peak point in the convex peak region as the representative point of the convex peak.

10. The assembly apparatus according to claim 9, characterized in that, The representative point determination unit further includes a fixed representative point subunit for determining a fixed representative point corresponding to the convex peak region from the fixed surface, wherein the fixed representative point subunit is specifically used for: The fixed surface is meshed to obtain mesh points; For each surface region in the fixed surface that corresponds to the convex peak region, a preset number of gridded points that are closest to the convex peak region are selected from the surface region as fixed points; and the average value of the coordinates of each fixed point in the surface region is determined as a fixed representative point.

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