Multi-degree-of-freedom decoupling platform and control method

Abstract

The invention provides a multi-degree-of-freedom decoupling platform, a bearing system based on the multi-degree-of-freedom decoupling platform and a control method of the bearing system, the platform comprises an upper platform, a middle platform and a lower platform, the lower platform belongs to a fixed base, and a convex cylindrical surface is machined above the lower platform; a concave cylindrical surface with the same size as the lower table is processed at the contact part of the lower part of the middle table and the lower table; the concave cylindrical surface of the middle table can rotate and axially slide along the convex cylindrical surface of the lower table to release the translational degree of freedom and the rotational degree of freedom along the axis; a concave cylindrical surface is processed above the middle table, and the axis of the cylindrical surface is orthogonal to the axis of the lower cylindrical surface; a convex cylindrical surface with the same size as the concave cylindrical surface above the middle table is processed below the upper table; the upper table outer convex cylindrical surface can rotate along the middle table inner concave cylindrical surface and slide along the axis, and the translation freedom degree and the rotation freedom degree along the axis are released. By using the multi-degree-of-freedom decoupling platform, a test piece can freely move in two horizontal directions and two inclined rotation directions without friction at the same time.

Description

Technical Field

[0001] The invention belongs to the field of test equipment, and in particular relates to a multi-degree-of-freedom decoupling platform and a control method thereof. Background Art

[0002] When conducting full-rocket modal tests on large-sized test pieces such as launch vehicles, a weak-rigidity support structure at the bottom can be used to lift the test piece. It is usually necessary to connect in series a decoupling platform between the support structure and the test piece to release the two-way translational freedom and the two-way tilting and rotational freedom, so as to achieve the free boundary conditions required for the modal test.

[0003] For example, the Chinese patent with application number 202120413818.1, the invention name is multi-degree-of-freedom static pressure decoupling platform, which can meet the above requirements. The tilting degree of freedom decoupling mentioned in the above patent is achieved through the ball head and socket structure, but for heavy test pieces such as launch vehicles, the large-size ball head has high processing and assembly requirements, high production costs, and high assembly scrap rate. When testing the overall structure, the repair area of ​​the ball head and socket structure and the inspection and repair effect testing are difficult. Summary of the invention

[0004] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a multi-degree-of-freedom decoupling platform and a control method. The platform adopts two orthogonal cylindrical surface structures and designs a static pressure oil film on the contact surface to achieve frictionless motion in two orthogonal translational directions and two orthogonal tilting and rotational directions, and reduce the processing, assembly and testing costs of the decoupling platform.

[0005] The present invention provides a multi-degree-of-freedom decoupling platform, including an upper platform, a middle platform and a lower platform. Among them, the lower platform is a fixed base, and a convex cylindrical surface is processed on the upper side; a concave cylindrical surface of the same size as the lower platform is processed at the lower side of the middle platform where it contacts the lower platform; the concave cylindrical surface of the middle platform can rotate and slide axially along the convex cylindrical surface of the lower platform, releasing the translational freedom and rotational freedom along the axis; a concave cylindrical surface is processed on the upper side of the middle platform, and the axis of this cylindrical surface is orthogonal to the axis of the lower cylindrical surface; a convex cylindrical surface of the same size as the concave cylindrical surface on the upper side of the middle platform is processed on the lower side; the convex cylindrical surface of the upper platform can rotate and slide along the concave cylindrical surface of the middle platform, releasing the translational freedom and rotational freedom along the axis.

[0006] The concave cylindrical surface on the middle platform and the concave cylindrical surface on the lower platform of the multi-degree-of-freedom decoupling platform are respectively processed with n groups of independent static pressure oil chambers. High-pressure oil is sent into the static pressure oil chamber through a throttle and an oil circuit, so that a high-pressure oil film is formed in the cylindrical surfaces of the middle platform, the upper platform and the lower platform, thereby eliminating relative motion friction.

[0007] The total area of ​​the static oil chamber is related to the design load-bearing capacity of the decoupling mechanism.

[0008] Oil collecting grooves are arranged around the inner concave cylindrical surface on the middle platform and the lower inner concave cylindrical surface, and the high-pressure oil in the static pressure oil cavity flows out through the cylindrical surface gap and then flows into the oil collecting groove.

[0009] The multi-degree-of-freedom decoupling platform center platform is equipped with an oil inlet and an oil return port. Inside the center platform, the oil inlet is connected to the throttle and the static pressure oil chamber in sequence through the internal oil channel, and the oil return port is connected to the oil collecting tank through the internal oil channel; outside the center platform, the oil inlet is used to connect to the high-pressure oil supply pipeline, and the oil return port is used to connect to the negative pressure oil return pipeline.

[0010] The basic control method of the multi-degree-of-freedom decoupling platform is as follows:

[0011] S1: Oil supply pipeline connecting high-pressure oil source, negative pressure oil pump and multi-degree-of-freedom decoupling platform

[0012] S2: First turn on the negative pressure oil pump, then turn on the high pressure oil source to realize the oil supply and return of the multi-degree-of-freedom decoupling platform

[0013] S3: Place the test piece to be released on the multi-degree-of-freedom decoupling platform

[0014] Since it is inconvenient to repeatedly hoist the test piece, and it is difficult to hoist a large mass test piece as a whole, such as a launch vehicle, which is mostly hoisted in sections and assembled step by step, the present invention also provides a bearing system based on a multi-degree-of-freedom decoupling platform. The system includes: a multi-degree-of-freedom decoupling platform, a test piece, a bottom bearing mechanism, a lower limit device, an oil return pipeline, a negative pressure oil pump, a high-pressure oil source, and an oil supply pipeline.

[0015] The system control method is as follows:

[0016] K1: Connect the lower stage of the multi-degree-of-freedom decoupling platform to the bottom bearing mechanism capable of vertical movement;

[0017] K2: A lower limit device capable of bearing the mass of the test piece is arranged near the bottom bearing mechanism. The device can prevent the decoupling mechanism from contacting the test piece when the bearing mechanism falls;

[0018] K3: Place the test piece whose freedom needs to be released on the lower limit device;

[0019] K4: Oil supply pipeline connecting high-pressure oil source, negative pressure oil pump and multi-degree-of-freedom decoupling platform;

[0020] K5: First start the negative pressure oil pump, then start the high pressure oil source, to realize the oil supply and return of the multi-degree-of-freedom decoupling platform;

[0021] K6: Use the bottom bearing mechanism to lift the multi-degree-of-freedom decoupling platform and the test piece together.

[0022] The test piece can move freely and frictionlessly in two horizontal directions and two tilting and rotating directions at the same time, thus achieving decoupling of the test piece's movement.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. The present invention adopts a cylindrical structure as the mating surface. The cylindrical surface has the advantages of easy processing accuracy and detection accuracy, and the repair difficulty between cylindrical surfaces is small and easy to test.

[0025] 2. The present invention uses orthogonal cylindrical surfaces to release degrees of freedom. By arranging the matching cylindrical surfaces orthogonally, the multi-degree-of-freedom decoupling platform can release the translational degrees of freedom in two directions and the tilting and rotating degrees of freedom in two directions.

[0026] 3. The present invention can conveniently realize the test boundary conditions of test piece lifting and degree of freedom release. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention:

[0028] Figure 1 is an axonometric diagram of a multi-degree-of-freedom decoupling platform according to an embodiment of the present invention;

[0029] Figure 2 is an exploded diagram of a multi-degree-of-freedom decoupling platform according to an embodiment of the present invention;

[0030] Figure 3 The invention relates to a multi-degree-of-freedom decoupling platform bearing system according to an embodiment of the present invention.

[0031] Among them: 1-upper platform 2-middle platform 3-lower platform 4-fuel saver 5-oil inlet 6-oil return port 11-upper platform translation limit 12-upper platform limit axis 13-upper platform convex cylindrical surface 21-middle platform translation limit 1 22-middle platform concave cylindrical surface 1 23-static oil chamber 24-oil chamber oil inlet 25-oil collecting groove 26-middle platform flip Z-direction limit 27-middle platform translation limit 2 28-middle platform limit axis 29-middle platform concave cylindrical surface 2 31-lower platform translation limit 32-lower platform flip Z-direction limit 33-lower platform convex cylindrical surface A-multi-degree-of-freedom decoupling platform B-test piece C-bottom bearing mechanism D-lower limit device E-return oil pipeline F-negative pressure oil pump G-high pressure oil source H-oil supply pipeline DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] This embodiment provides a multi-degree-of-freedom decoupling platform, and its isometric view is as follows: Figure 1 As shown, the explosion diagram is as follows Figure 2 As shown, the upper platform (1) is located at the top of the multi-degree-of-freedom decoupling platform and is ultimately connected to the test piece; upper platform translation limits (11) are provided on both sides along the Y direction; an upper platform limit shaft (12) is installed on the upper platform translation limit (11); and an upper platform convex cylindrical surface (13) is machined at the bottom.

[0034] The middle platform (2) is located in the middle of the decoupling platform; the middle platform translation limiter 1 (21) is installed on both sides of the Y direction; the middle platform translation limiter 1 (21) is processed with a middle platform flip and a Z direction limiter (26); the middle platform is processed with a middle platform concave cylindrical surface 1 (22) above the middle platform, and the concave cylindrical surface 1 (22) is processed with a static pressure oil cavity (23) and an oil collecting groove (25), and an oil cavity inlet (24) is arranged at the center of the static pressure oil cavity (23) to inlet oil. The opening (5) and the oil return opening (6) are arranged on the middle platform (2) for supplying and returning oil to the platform; the middle platform is provided with middle platform translation limit stops 2 (27) on both sides along the X direction; a middle platform limit shaft (28) is installed on the side of the middle platform; a middle platform concave cylindrical surface 2 (29) is processed below the middle platform, and a static pressure oil cavity (23) is also processed on the middle platform concave cylindrical surface 2 (29); an oil inlet (24) is arranged at the center of the static pressure oil cavity (23).

[0035] The lower platform (3) is located at the bottom of the decoupling platform and is connected to the bearing mechanism; lower platform translation limiters (31) are installed on both sides along the X direction; lower platform flip and Z direction limiters (32) are provided on the lower platform translation limiters (31); and a lower platform convex cylindrical surface (33) is processed on the upper side.

[0036] The upper platform (1) is installed on the concave cylindrical surface 1 (22) of the middle platform (2) through the upper platform outer convex cylindrical surface (13); the upper platform outer convex cylindrical surface (13) and the concave cylindrical surface 1 (22) of the middle platform are coaxial; the upper platform (1) can be flipped around the Y axis relative to the middle platform (2); the upper platform (1) can be translated along the Y axis relative to the middle platform (2); the upper platform limit axis (12) on the upper platform (1) passes through the middle platform flipping and Z-direction limit (26), and when the upper platform (1) flips, the flip angle is limited, and the limit can be performed when there is a jump in the Z direction. When the upper platform (1) is translated along the Y axis, the upper platform translation limit (11) on the upper platform (1) is limited by the middle platform translation limit 1 (21) on the middle platform (2).

[0037] The middle platform (2) is installed on the lower platform convex cylindrical surface (33) of the lower platform (3) through the middle platform concave cylindrical surface 2 (29); the middle platform concave cylindrical surface 2 (29) and the lower platform convex cylindrical surface (33) are coaxial; the middle platform (2) can be flipped around the X-axis relative to the lower platform (3); the middle platform (2) can be translated along the X-axis relative to the lower platform (3); the middle platform limit axis (28) on the middle platform (2) passes through the lower platform flipping and Z-direction limit (32), and when the middle platform (2) flips, the flip angle is limited, and the limit can be performed when there is a jump in the Z direction. When the middle platform (2) is translated along the X-axis, the middle platform translation limit 2 (27) of the middle platform (2) is limited by the lower platform translation limit (31) on the lower platform (3).

[0038] The high-pressure oil between the two inner concave cylindrical surfaces 1 (22) and the inner concave cylindrical surface 2 (29) of the middle platform (2) comes from the overflow of the static oil chamber (23). The oil in the static oil chamber (23) is supplied through the oil chamber oil inlet (24). The high-pressure oil flows out through the cylindrical gap and then flows into the oil collecting tank (25). It can ensure that a high-pressure oil film is formed between the inner concave cylindrical surface 1 (22) of the middle platform and the outer convex cylindrical surface (13) of the upper platform, and between the inner concave cylindrical surface 2 (29) of the middle platform and the outer convex cylindrical surface (33) of the lower platform, thereby eliminating the friction force during the relative movement between the upper platform (1) and the middle platform (2), and between the middle platform (2) and the lower platform (3). The axes of the two inner concave cylindrical surfaces 1 (22) and the inner concave cylindrical surface 2 (29) of the middle platform (2) are orthogonally distributed, realizing the release of the two-direction translational freedom and the two-direction flipping freedom.

[0039] The contact surfaces of the upper platform (1), the middle platform (2) and the lower platform (3) are cylindrical surfaces. The cylindrical surface is relative to the spherical surface, and the processing requirements on the machine tool are low. The processing accuracy is easy to ensure and the processing quality is easy to detect. When the decoupling platform is tested and debugged, the difficulty of repairing the cylindrical surface is less than that of repairing the spherical surface.

[0040] Since it is inconvenient to repeatedly hoist the test piece, and it is difficult to hoist a large mass test piece as a whole, such as a launch vehicle, which is mostly hoisted in sections and assembled step by step, this embodiment also provides a bearing system based on a multi-degree-of-freedom decoupling platform. Figure 3As shown, the system includes: a multi-degree-of-freedom decoupling platform, a test piece, a bottom bearing mechanism, a lower limit device, an oil return pipeline, a negative pressure oil pump, a high-pressure oil source, and an oil supply pipeline.

[0041] The system control method is as follows:

[0042] K1: Connect the lower stage of the decoupling platform A to the vertically movable bottom bearing mechanism C;

[0043] K2: A lower limit device D capable of bearing the mass of the test piece is arranged near the bottom bearing mechanism C. The device can prevent the multi-degree-of-freedom decoupling mechanism from contacting the test piece when the bottom bearing mechanism falls;

[0044] K3: Place the test piece whose freedom needs to be released on the lower limit device D;

[0045] K4: oil supply pipeline connecting high-pressure oil source G, negative pressure oil pump F and decoupling platform A;

[0046] K5: First turn on the negative pressure oil pump F, then turn on the high pressure oil source G to realize the oil supply and return of the multi-degree-of-freedom decoupling platform;

[0047] K6: Use the bottom bearing mechanism C to lift the multi-degree-of-freedom decoupling platform A and the test piece B together.

[0048] After following the above steps, the test piece can move freely and frictionlessly in two horizontal directions and two tilting and rotating directions at the same time, which means that the motion of the test piece is decoupled. Usually, three or more decoupling platforms are required to work together to carry the same test piece, which can be used in applications where the test piece needs to be lifted without translational or rotational constraints.

[0049] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-degree-of-freedom decoupling platform, characterized in that: Including going on stage, mid-stage and leaving stage; The lower platform is a fixed base, and a convex cylindrical surface is machined on the top; A lower concave cylindrical surface of the same size as the lower table is processed at the contact point between the middle table and the lower table; the concave cylindrical surface of the middle table can rotate and slide axially along the convex cylindrical surface of the lower table, releasing the translational freedom and rotational freedom along the axis; An upper concave cylindrical surface is machined above the center platform, and the axis of the cylindrical surface is orthogonal to the axis of the lower cylindrical surface; A convex cylindrical surface of the same size as the concave cylindrical surface above the middle platform is processed below the upper platform; the convex cylindrical surface of the upper platform can rotate and slide along the concave cylindrical surface of the middle platform, releasing the translational freedom and rotational freedom along the axis.

2. A multi-degree-of-freedom decoupling platform according to claim 1, characterized in that: The concave cylindrical surface on the middle platform and the lower concave cylindrical surface of the multi-degree-of-freedom decoupling platform are respectively processed with multiple sets of independent static pressure oil chambers, and high-pressure oil is sent into the static pressure oil chamber through the throttle and the oil circuit, so that a high-pressure oil film is formed in the cylindrical surfaces of the middle platform, the upper platform and the lower platform, which can eliminate the friction of relative motion.

3. A multi-degree-of-freedom decoupling platform according to claim 2, characterized in that: Oil collecting grooves are designed around the upper concave cylindrical surface and the lower concave cylindrical surface of the middle platform, and the high-pressure oil in the static pressure oil cavity flows out through the cylindrical surface gap and then flows into the oil collecting groove.

4. A multi-degree-of-freedom decoupling platform according to claim 3, characterized in that: The middle platform is equipped with an oil inlet and an oil return port.

5. A multi-degree-of-freedom decoupling platform according to claim 4, characterized in that: Inside the center platform, the oil inlet is connected to the throttle and the static oil chamber in sequence through the internal oil passage, and the oil return port is connected to the oil collecting tank through the internal oil passage.

6. A multi-degree-of-freedom decoupling platform according to claim 4, characterized in that: Outside the center platform, the oil inlet is used to connect to the high-pressure oil supply pipeline, and the oil return port is used to connect to the negative-pressure oil return pipeline.

7. A multi-degree-of-freedom decoupling platform according to claims 1-6, characterized in that: Multiple multi-DOF decoupling platforms can be used collaboratively to carry the same test piece.

8. A multi-degree-of-freedom decoupling platform according to claims 1-7, characterized in that: The test piece can be freely moved without friction in two horizontal directions and two tilting and rotating directions at the same time.

9. A bearing system based on the multi-degree-of-freedom decoupling platform according to claims 1-8, characterized in that: The system comprises: a multi-degree-of-freedom decoupling platform, a bottom bearing mechanism, a lower limit device, an oil return pipeline, a negative pressure oil pump, a high-pressure oil source, and an oil supply pipeline; the bottom bearing mechanism is a vertically movable bearing mechanism, and the lower platform of the multi-degree-of-freedom decoupling platform is fixedly connected to the bottom bearing mechanism; the lower limit device can prevent the decoupling mechanism from contacting the test piece when the bottom bearing mechanism falls.

10. A control method for a bearing system of a multi-degree-of-freedom decoupling platform as claimed in claim 9, characterized in that: The steps include: 1) The lower stage of the multi-degree-of-freedom decoupling platform is fixedly connected to the bottom bearing mechanism capable of vertical movement; 2) Arrange a lower limit device near the bottom bearing mechanism that can bear the mass of the test piece; 3) Place the test piece whose freedom needs to be released on the lower limit device; 4) Oil supply pipeline connecting high-pressure oil source, negative pressure oil pump and multi-degree-of-freedom decoupling platform; 5) First start the negative pressure oil pump, then start the high pressure oil source, to realize the oil supply and return of the multi-degree-of-freedom decoupling platform; 6) Use the bottom bearing mechanism to lift the multi-degree-of-freedom decoupling platform and the test piece together.

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