A four-bar linkage four-position solution method for defining the length of a double-connected linkage bar

Abstract

The application belongs to the technical field of mechanical design, and particularly relates to a four-bar mechanism connecting rod four-position solving method for limiting the length of double connecting rods. The four-bar mechanism connecting rod four-position solving method for limiting the length of double connecting rods ingeniously integrates the current widely used computer-aided design software technology, and automatically solves a planar four-bar mechanism design scheme which meets the length requirement of double connecting rods and conforms to the four-position constraint condition of connecting rods by using the powerful computing capacity of the software. Compared with the traditional experimental method, the method significantly reduces the blindness of design, ensures the high-precision realization of the trajectory, and greatly reduces the cost investment. On the other hand, the method effectively avoids the operation difficulty caused by the complex algorithm of the traditional analytic method, makes the design process more intuitive and simple, significantly improves the design efficiency, and greatly promotes the popularization and application of the technology.

Description

Technical Field

[0001] This application belongs to the field of mechanical design technology, and specifically relates to a method for solving the four positions of a four-bar linkage with a limited length of double connecting rods. Background Technology

[0002] As a widely used mechanism in the field of mechanical design, the planar four-bar linkage has excellent operability, simplicity of principle and reliability, as well as the ability to realize complex and varied motion trajectories.

[0003] However, current design methods for planar four-bar linkages are still insufficient. Traditional experimental methods face challenges due to their high degree of blindness, limited trajectory control accuracy, and high economic cost. While analytical methods can provide higher accuracy, they are difficult to promote and apply on a large scale due to their complex algorithms and low design efficiency.

[0004] In view of the above situation, it is particularly urgent and important to develop a method for solving the four positions of a four-bar linkage with a limited double-link length that is both efficient and accurate, easy to operate and suitable for wide application. This is of profound significance for promoting the innovation and progress of planar four-bar linkage design.

[0005] Therefore, there is an urgent need for a technical solution to overcome or mitigate at least one of the aforementioned defects in the existing technology. Summary of the Invention

[0006] The purpose of this application is to provide a method for solving the four-position problem of a four-bar linkage with a limited length of double connecting rods, so as to solve at least one problem existing in the prior art.

[0007] The technical solution of this application is:

[0008] The first aspect of this application provides a method for solving the four positions of a four-bar linkage with a limited length of double connecting rods. The positions of two hinge points O1 and O2 fixed to the frame of the four-bar linkage are unknown. The lengths of the two connecting rods O1A and O2B connected to the hinge points O1 and O2 and the connecting rod AB are limited to a preset length. During operation, line segment CD on the connecting rod AB successively reaches four positions: C1D1, C2D2, C3D3, and C4D4.

[0009] Draw line segments C1D1, C2D2, C3D3, and C4D4 based on the given coordinate positions;

[0010] For each line segment C1D1, C2D2, C3D3, C4D4, set a hinge point A1, A2, A3, A4 corresponding to the connecting rod AB, such that △A1C1D1≌△A2C2D2≌△A3C3D3≌△A4C4D4, where A1C1= A2C2= A3C3= A4C4, A1D1= A2D2=A3D3= A4D4;

[0011] Draw any circle O1 through three of the hinge points A1, A2, A3, and A4 respectively. Add a constraint on the hinge point A4 on the circle O1 so that the hinge points A1, A2, A3, and A4 are on the same circle O1. Set the radius of the circle O1 to the length of the connecting rod O1A.

[0012] For each line segment C1D1, C2D2, C3D3, C4D4, set another hinge point B1, B2, B3, B4 for the connecting rod AB, such that △B1C1D1≌△B2C2D2≌△B3C3D3≌△B4C4D4, where B1C1= B2C2= B3C3= B4C4, and B1D1= B2D2= B3D3= B4D4;

[0013] Draw any circle O2 through three of the hinge points B1, B2, B3, and B4 respectively. Add a constraint on the hinge point B4 on the circle O2 so that the hinge points B1, B2, B3, and B4 are on the same circle O2. Set the radius of the circle O2 to the length of the connecting rod O2B.

[0014] By setting quadrilaterals A1C1B1D1, A2C2B2D2, A3C3B3D3, and A4C4B4D4 as the four positions of link AB, a planar four-bar linkage O1ABO2 is obtained.

[0015] In at least one embodiment of this application, the planar four-bar linkage O1ABO2 is designed using CAD software.

[0016] In at least one embodiment of this application, the opening and closing of the aircraft hatch is achieved by a planar four-bar linkage O1ABO2.

[0017] A second aspect of this application provides an electronic device including a processor, a memory, and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to implement the method for solving the four-position problem of a four-bar linkage with a defined double-link length as described above.

[0018] A third aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, enables the implementation of the method described above for solving the four-position problem of a four-bar linkage with a defined double-link length.

[0019] The invention has at least the following beneficial technical effects:

[0020] The method for solving the four positions of a four-bar linkage with a limited double-link length in this application simplifies the design process of a planar four-bar linkage and makes it highly feasible by directly transforming the complex design constraints of the planar four-bar linkage into geometric constraints that are easy to process in CAD software. It is efficient, accurate and easy to operate. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the four positions of the linkage of a planar four-bar linkage according to one embodiment of this application;

[0022] Figure 2 This is a schematic diagram showing the four positions of hinge point A in one embodiment of this application;

[0023] Figure 3 This is a schematic diagram of circle O1 drawn through hinge points A1, A2, and A3 according to one embodiment of this application;

[0024] Figure 4 This is a schematic diagram of circle O1 drawn through hinge points A1, A2, A3, and A4 according to one embodiment of this application;

[0025] Figure 5 This is a schematic diagram showing the four positions of hinge point B in one embodiment of this application;

[0026] Figure 6 This is a schematic diagram of circle O2 drawn through hinge points B1, B2, B3, and B4 according to one embodiment of this application;

[0027] Figure 7 This is a schematic diagram of a planar four-bar linkage located in quadrilateral A1C1B1D1 according to one embodiment of this application;

[0028] Figure 8 This is a schematic diagram of a planar four-bar linkage located in quadrilateral A2C2B2D2 according to one embodiment of this application;

[0029] Figure 9 This is a schematic diagram of a planar four-bar linkage located in quadrilateral A3C3B3D3 according to one embodiment of this application;

[0030] Figure 10 This is a schematic diagram of a planar four-bar linkage located in quadrilateral A4C4B4D4 according to one embodiment of this application; Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0032] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this application.

[0033] The following is in conjunction with the appendix Figures 1 to 10 This application will be described in further detail.

[0034] This application provides a method for solving the four positions of links in a four-bar linkage with a limited length of double connecting rods. The method limits the length of the double connecting rods and solves for the four positions of links in a planar four-bar linkage. The positions of two hinge points O1 and O2 fixed to the frame in this four-bar linkage are unknown. The lengths of the two connecting rods O1A and O2B connected to connecting rod AB at hinge points O1 and O2 are limited to a preset length. During operation, line segment CD on connecting rod AB successively reaches four positions: C1D1, C2D2, C3D3, and C4D4. Figure 1 As shown.

[0035] The method for solving the four-position problem of a four-bar linkage with a limited double-link length in this application includes the following steps:

[0036] Draw line segments C1D1, C2D2, C3D3, and C4D4 based on the given coordinate positions;

[0037] For each line segment C1D1, C2D2, C3D3, C4D4, set a hinge point A1, A2, A3, A4 corresponding to the connecting rod AB, such that △A1C1D1≌△A2C2D2≌△A3C3D3≌△A4C4D4, where A1C1= A2C2= A3C3= A4C4, A1D1= A2D2=A3D3= A4D4;

[0038] Draw any circle O1 through three of the hinge points A1, A2, A3, and A4 respectively. Add a constraint on the hinge point A4 on the circle O1 so that the hinge points A1, A2, A3, and A4 are on the same circle O1. Set the radius of the circle O1 to the length of the connecting rod O1A.

[0039] For each line segment C1D1, C2D2, C3D3, C4D4, set another hinge point B1, B2, B3, B4 for the connecting rod AB, such that △B1C1D1≌△B2C2D2≌△B3C3D3≌△B4C4D4, where B1C1= B2C2= B3C3= B4C4, and B1D1= B2D2= B3D3= B4D4;

[0040] Draw any circle O2 through three of the hinge points B1, B2, B3, and B4 respectively. Add a constraint on the hinge point B4 on the circle O2 so that the hinge points B1, B2, B3, and B4 are on the same circle O2. Set the radius of the circle O2 to the length of the connecting rod O2B.

[0041] By setting quadrilaterals A1C1B1D1, A2C2B2D2, A3C3B3D3, and A4C4B4D4 as the four positions of link AB, a planar four-bar linkage O1ABO2 is obtained.

[0042] In one application scenario of this application, two hinge points O1 and O2 are located on the aircraft fuselage, and two hinge points A and B are located on the aircraft hatch. The aircraft fuselage and the aircraft hatch are connected by two connecting rods O1A and O2B. During the opening and closing of the aircraft hatch, the aircraft hatch needs to reach four positions C1D1, C2D2, C3D3, and C4D4 in sequence. The four-bar linkage designed in the above manner can realize the opening and closing of the aircraft hatch.

[0043] In one specific embodiment of this application, the planar four-bar linkage O1ABO2 is designed using CAD software. The specific process is as follows:

[0044] 1) Use the sketching function of the CAD software in the computer-aided design software UG to draw line segments C1D1, C2D2, C3D3, and C4D4 according to the given coordinate positions.

[0045] 2) Assuming a hinge point of link AB is A, then relative to the four positions of line segment CD, A has four positions: A1, A2, A3, and A4. Using CAD software, add geometric constraints to the drawing: A1C1 = A2C2 = A3C3 = A4C4, A1D1 = A2D2 = A3D3 = A4D4, such that △A1C1D1≌△A2C2D2≌△A3C3D3≌△A4C4D4 (although the positions of hinge points A1, A2, A3, and A4 are not fixed, dragging any point maintains the same relative position with C1D1, C2D2, C3D3, and C4D4 respectively). Figure 2 As shown.

[0046] 3) In the sketch, draw any circle O1 passing through three points A1, A2, A3, and A4 respectively, such as... Figure 3 As shown. Continue adding constraints on A4 on circle O1. Since the center position and radius of circle O1 are not fixed, it is possible to make the four points A1, A2, A3, and A4 lie on the same circle O1. Then, by further limiting the radius of circle O1 (setting it to the length of the connecting rod O1A), a unique circle O1 can be determined, as shown. Figure 4 As shown.

[0047] 4) Similarly, based on the already determined constraint circle O1, for the other hinge point B of link AB, the four positions relative to line segment CD are B1, B2, B3, and B4. Using CAD software, geometric constraints are added to the drawing: B1C1 = B2C2 = B3C3 = B4C4, B1D1 = B2D2 = B3D3 = B4D4, such that △B1C1D1≌△B2C2D2≌△B3C3D3≌△B4C4D4 (although the positions of points B1, B2, B3, and B4 are not fixed, they maintain the same relative position with C1D1, C2D2, C3D3, and C4D4 when any point is dragged). Figure 5 As shown.

[0048] 5) Similarly, the constraint circle O2 determined by B1, B2, B3, and B4 can be determined. If the radius of circle O2 is fixed (set to the length of the specified connecting rod O2B), then there can be a unique circle O2, such as... Figure 6 As shown.

[0049] 6) Quadrilaterals A1C1B1D1, A2C2B2D2, A3C3B3D3, and A4C4B4D4 represent the four corresponding positions of link AB, thus obtaining the planar four-bar linkage O1ABO2. Figure 7-10 As shown.

[0050] This application presents a method for solving the four-linkage constraint of a four-bar linkage with limited double-link length. This method ingeniously integrates widely used computer-aided design software, leveraging the software's powerful computational capabilities to automatically solve for a planar four-bar linkage design that satisfies both the double-link length requirement and the four-linkage constraint. Compared to traditional experimental methods, this method significantly reduces the blind spots in design, ensures high-precision trajectory realization, and substantially reduces costs. Furthermore, it effectively avoids the operational difficulties caused by the complexity of traditional analytical methods, making the design process more intuitive and convenient, significantly improving design efficiency, and greatly promoting the popularization and application of this technology. This application can be widely applied in the aerospace field and many mechanical engineering fields, bringing significant economic and social benefits, and possesses enormous application value and promising prospects.

[0051] Another aspect of this application provides an electronic device, including a processor, a memory, and a computer program stored in the memory and capable of running on the processor. When the processor executes the computer program, it implements the above-described method for solving the four-position problem of a four-bar linkage that limits the length of a double-link mechanism.

[0052] In another aspect, this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the above-described method for solving the four-position problem of a four-bar linkage with a limited double-link length.

[0053] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining the four positions of a four-bar linkage with a limited length of double connecting rods, wherein the positions of two hinge points O1 and O2 fixed on the frame of the four-bar linkage are unknown, the lengths of the two connecting rods O1A and O2B connected to the hinge points O1 and O2 and the connecting rod AB are limited to a preset length, and during the operation of the four-bar linkage, the line segment CD on the connecting rod AB successively reaches four positions C1D1, C2D2, C3D3, and C4D4, characterized in that... include: Draw line segments C1D1, C2D2, C3D3, and C4D4 based on the given coordinate positions; For each line segment C1D1, C2D2, C3D3, C4D4, set a hinge point A1, A2, A3, A4 corresponding to the connecting rod AB, such that △A1C1D1≌△A2C2D2≌△A3C3D3≌△A4C4D4, where A1C1= A2C2= A3C3= A4C4, A1D1= A2D2= A3D3=A4D4; Draw any circle O1 through three of the hinge points A1, A2, A3, and A4 respectively. Add a constraint on the hinge point A4 on the circle O1 so that the hinge points A1, A2, A3, and A4 are on the same circle O1. Set the radius of the circle O1 to the length of the connecting rod O1A. For each line segment C1D1, C2D2, C3D3, C4D4, set another hinge point B1, B2, B3, B4 for the connecting rod AB, such that △B1C1D1≌△B2C2D2≌△B3C3D3≌△B4C4D4, where B1C1= B2C2= B3C3= B4C4, and B1D1= B2D2= B3D3=B4D4; Draw any circle O2 through three of the hinge points B1, B2, B3, and B4 respectively. Add a constraint on the hinge point B4 on the circle O2 so that the hinge points B1, B2, B3, and B4 are on the same circle O2. Set the radius of the circle O2 to the length of the connecting rod O2B. By setting quadrilaterals A1C1B1D1, A2C2B2D2, A3C3B3D3, and A4C4B4D4 as the four positions of link AB, a planar four-bar linkage O1ABO2 is obtained.

2. The method for solving the four positions of a four-bar linkage with a limited double-link length according to claim 1, characterized in that, The planar four-bar linkage O1ABO2 was designed using CAD software.

3. The method for solving the four positions of a four-bar linkage with a limited double-link length according to claim 2, characterized in that, The aircraft hatch is opened and closed using a planar four-bar linkage O1ABO2.

4. An electronic device comprising a processor, a memory, and a computer program stored in the memory and capable of running on the processor, characterized in that, When the processor executes the computer program, it implements the method for solving the four positions of a four-bar linkage with a limited double-link length as described in any one of claims 1 to 3.

5. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it can implement the method for solving the four positions of the linkage of a four-bar linkage with a limited double-link length as described in any one of claims 1 to 3.

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