阅读说明：本技术 一种基于双基准约束的精加工配准方法 (Finish machining registration method based on double-reference constraint ) 是由 朱燏 肖世宏 王文理 于 2019-11-19 设计创作，主要内容包括：本发明公开了一种基于双基准约束的精加工配准方法,包括以下步骤：S1：根据平面和圆柱面分别得到平面理论基准和圆柱面理论基准；S2：对零件的待加工面、平面和圆柱面分别进行检测,分别得到待加工面检测点、平面检测点和圆柱面检测点；S3：通过平面拟合基准/圆柱面拟合基准向平面理论基准/圆柱面理论基准运动,得到第一平移矢量T<Sub>1</Sub>和第一旋转矩阵R<Sub>1</Sub>,再根据第一平移矢量T<Sub>1</Sub>和第一旋转矩阵R<Sub>1</Sub>将待加工面检测点进行变换；S4：根据平面理论基准和圆柱面理论基准建立局部坐标系,然后在局部坐标系下建立带有两个基准面约束的配准模型；S5：输出最终计算结果。本发明应用于机械加工领域。(The invention discloses a fine machining registration method based on double reference constraints, which comprises the following steps: s1: respectively obtaining a plane theoretical reference and a cylindrical surface theoretical reference according to the plane and the cylindrical surface; s2: respectively detecting a surface to be processed, a plane and a cylindrical surface of the part to respectively obtain a detection point of the surface to be processed, a plane detection point and a cylindrical surface detection point; s3: the first translation vector T is obtained by moving the plane fitting reference/the cylindrical surface fitting reference to the plane theoretical reference/the cylindrical surface theoretical reference 1 And a first rotation matrix R 1 And then according to the first translation vector T 1 And a first rotation matrix R 1 Changing a detection point of a surface to be processed; s4: establishing a local coordinate system according to a plane theoretical reference and a cylindrical surface theoretical reference, and then establishing a fitting with two reference surface constraints under the local coordinate systemA quasi model; s5: and outputting a final calculation result. The invention is applied to the field of machining.)

1. A fine finishing registration method based on double reference constraints is characterized by comprising the following steps:

s1: after a part to be processed is fixed, two reference parts are determined according to the surface to be processed of the part, the reference parts are a plane and a cylindrical surface, and a plane theoretical datum and a cylindrical surface theoretical datum are respectively obtained according to the plane and the cylindrical surface;

s2: respectively detecting a surface to be processed, a plane and a cylindrical surface of the part to respectively obtain a detection point of the surface to be processed, a plane detection point and a cylindrical surface detection point;

s3: respectively fitting two groups of plane detection points and cylindrical surface detection points to obtain a plane fitting reference and a cylindrical surface fitting reference, wherein the plane fitting reference and the cylindrical surface fitting reference are perpendicular to each other, and moving to the plane theoretical reference/the cylindrical surface theoretical reference through the plane fitting reference/the cylindrical surface fitting reference to obtain a first translation vector T₁And a first rotation matrix R₁And then according to the first translation vector T₁And a first rotation matrix R₁Changing a detection point of a surface to be processed;

s4: establishing a local coordinate system according to the constraint of a plane theoretical datum and a cylindrical surface theoretical datum, then establishing a registration model under the local coordinate system, and controlling the transformation process to move along the two theoretical datums by controlling the freedom of movement in the registration model;

s5: solving the registration result under the local coordinate system and converting the registration result in the local coordinate system into the global coordinate system to obtain a second translation vector T₂And a second rotation matrix R₂And outputting the final result.

2. The fine processing registration method based on the dual-reference constraint of claim 1, wherein in step S5, the local coordinate system is imported into the global coordinate system to obtain a second rotation matrix R₂And a second translation vector T₂And the output result is as follows: r₁R₂，(T₁+T₂)。

3. The fine processing registration method based on the dual-reference constraint of claim 1, wherein in step S4, the origin of the local coordinate system is set at the intersection of the central axis of the cylindrical surface and the plane, and the Z axis of the local coordinate system is set on the central axis of the cylindrical surface.

4. The fine processing registration method based on the double-reference constraint of claim 1, wherein in step S4, a local coordinate system is established according to the cylindrical surface theoretical reference and the plane theoretical reference, the degrees of freedom of a transformation matrix used in the registration process under the local coordinate system are constrained according to the cylindrical surface theoretical reference and the plane theoretical reference, and then a registration model based on the constraint is established under the local coordinate system.

5. The fine processing registration method based on double reference constraints as claimed in claim 4, wherein in step S4, a local coordinate system is established, then a registration model with a machining allowance constraint, a cylindrical surface theoretical reference and a plane theoretical reference constraint is established under the local coordinate system, and the number of variables in the registration model is controlled in the local coordinate system to control the freedom of movement, so that no deviation of the reference surface occurs in the registration process.

6. The dual-reference-constraint-based finishing registration method according to claim 1, wherein in step S1, the part to be machined is fixed on a numerically controlled machine tool; in step S2, the surface to be processed, the plane, and the cylindrical surface of the part are detected by the numerical control machine tool, and a detection point of the surface to be processed, a detection point of the plane, and a detection point of the cylindrical surface are obtained.

Technical Field

The invention relates to the technical field of machining, in particular to a fine machining registration method based on double reference constraints.

Background

In the field of aerospace manufacturing, there are demanding assembly relationships between a large number of parts. For such parts, the location of the mounting plane and the mounting hole (or mounting shaft) is extremely important, and other geometric features are required to first ensure the positional relationship with respect to the mounting plane and the mounting hole (or mounting shaft). The mounting plane of such parts is usually perpendicular to the mounting hole (or mounting shaft) and preparation is already done prior to finishing of the critical profile, and the face to be finished has only a small machining allowance. For example, in the blade finishing process of a blisk of an aircraft engine, reference planes and reference holes perpendicular to the reference planes are already prepared on the blisk web, but a small amount of machining allowance still remains on the blade to be machined. In order to ensure the position degree of the blades after numerical control machining of the blisk, the position relation of the machined blades relative to a plane reference and a cylindrical surface reference must be maintained in the self-adaptive milling of the blisk blades, and then the blades have better margin distribution by adjusting the theoretical position of each blade.

For the part prepared by the reference surface and the reference hole (or the reference shaft), in the process of realizing the self-adaptive positioning of the part by adopting a registration technology based on a detection point, the registration can not be carried out only by depending on the minimum distance between the detection point of the surface to be processed and the theoretical curved surface of the surface to be processed. This results in the surface to be machined losing its positional relationship with respect to the cylindrical surface reference, although matching between the blank and the surface to be machined is possible.

Therefore, in the registration process, the reference plane on the design model must be unified with the reference plane on the blank first, and the positions of the reference holes (or reference axes) on the design model and the reference holes (or reference axes) on the blank must be unified. And then, registering the surface to be processed on the premise of ensuring that the plane reference and the cylindrical surface reference are not moved, thereby realizing the self-adaptive positioning of the positions of the reference plane and the reference hole (or the reference shaft).

Disclosure of Invention

Technical problem to be solved

The invention provides a finish machining registration method based on double-datum constraint, which can ensure the relative position relationship between a part and a plane theoretical datum and a cylindrical surface theoretical datum and ensure the position precision of a surface to be machined relative to the plane datum and the cylindrical surface datum, thereby ensuring the matching between the part and other parts; the method can improve the calculation efficiency of the parts in the registration process, reduce the time required by the registration process and improve the processing precision.

(II) technical scheme

In order to solve the technical problem, the invention provides a fine machining registration method based on double reference constraints, which comprises the following steps:

s1: after a part to be processed is fixed, two reference parts are determined according to the surface to be processed of the part, the reference parts are a plane and a cylindrical surface, and a plane theoretical datum and a cylindrical surface theoretical datum are respectively obtained according to the plane and the cylindrical surface;

s2: respectively detecting a surface to be processed, a plane and a cylindrical surface of the part to respectively obtain a detection point of the surface to be processed, a plane detection point and a cylindrical surface detection point;

s3: respectively fitting two groups of plane detection points and cylindrical surface detection points to obtain a plane fitting reference and a cylindrical surface fitting reference, wherein the plane fitting reference and the cylindrical surface fitting reference are perpendicular to each other, and moving to the plane theoretical reference/the cylindrical surface theoretical reference through the plane fitting reference/the cylindrical surface fitting reference to obtain a first translation vector T₁And a first rotation matrix R₁And then according to the first translation vector T₁And a first rotation matrix R₁Changing a detection point of a surface to be processed;

s4: establishing a local coordinate system according to plane theoretical reference and cylindrical surface theoretical reference constraint, then establishing a registration model under the local coordinate system, constraining the freedom of motion through the local coordinate system, controlling the machining allowance of a surface to be machined through allowance constraint, and solving the registration model;

s5: and converting the registration result in the local coordinate system into a global coordinate system, and outputting a final result.

In step S5, a second rotation matrix R is obtained by importing the local coordinate system into the global coordinate system₂And a second translation vector T₂And the output result is as follows: r₁R₂，(T₁+T₂)。

In a further modification, in step S4, the origin of the local coordinate system is set at the intersection of the central axis of the cylindrical surface and the plane, and the Z axis of the local coordinate system is set on the central axis of the cylindrical surface.

In step S4, a local coordinate system is established according to the cylindrical surface theoretical standard and the plane theoretical standard, the degree of freedom of a transformation matrix used in the registration process in the local coordinate system is constrained according to the cylindrical surface theoretical standard and the plane theoretical standard, so that the part can only rotate around one axis of the local coordinate system in the transformation process, and then a registration model based on the constraint is established in the local coordinate system.

In step S4, a local coordinate system is established, and then a registration model with a machining allowance constraint, a cylindrical surface theoretical reference and a plane theoretical reference constraint is established in the local coordinate system, and the number of variables in the registration model is controlled in the local coordinate system to control the degree of freedom of motion, so that the reference plane does not deviate during the registration process.

In a further improvement, in step S1, the part to be machined is fixed on a numerical control machine; in step S2, the surface to be processed, the plane, and the cylindrical surface of the part are detected by the numerical control machine tool, and a detection point of the surface to be processed, a detection point of the plane, and a detection point of the cylindrical surface are obtained.

(III) advantageous effects

The technical scheme of the invention has the following advantages:

the first translation vector T is obtained by moving the plane fitting reference/the cylindrical surface fitting reference to the plane theoretical reference/the cylindrical surface theoretical reference₁And a first rotation matrix R₁According to the first rotation matrix R₁And a first translation vector T₁And changing the detection point of the surface to be processed. And for the detection point of the surface to be processed after transformation, establishing corresponding motion constraint according to the plane theoretical datum and the cylinder theoretical datum, namely constraining the motion freedom of the part in the registration process through the plane theoretical datum and the cylinder theoretical datum, thereby ensuring the position relation of the surface to be processed of the part after registration relative to the plane theoretical datum and the cylinder theoretical datum, and ensuring the matching of the part and other parts. The registration method can reduce the number of parts in the calculation processThe required time improves the position accuracy of the machined part.

Drawings

FIG. 1 is a schematic structural view of a part to be machined;

FIG. 2 is a schematic view of a part to be machined having a surface to be machined detection point and two sets of datum detection points;

FIG. 3 is a schematic illustration of establishing a fit reference;

FIG. 4 is a schematic diagram of a part in establishing a local coordinate system and a global coordinate system;

FIG. 5 is a schematic diagram of establishing a registration model under a local coordinate system;

fig. 6 is a schematic diagram of a process of outputting a result.

In the figure: 1. processing the noodles; 2. theoretical reference of a cylindrical surface; 3. a plane theoretical standard; 4. detecting points of a surface to be processed; 5. detecting a cylindrical surface; 6. detecting a plane; 7. a local coordinate system; 8. a global coordinate system; 10. registering theoretical points of the surface to be processed and detection points of the surface to be processed; 11. registering the plane reference theoretical point and the plane detection point; 12. and (4) registering the cylindrical surface reference theoretical point and the cylindrical surface detection point.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.