A three-degree-of-freedom simulation air flotation test system and a motion platform positioning method thereof

Abstract

The present invention discloses a three-degree-of-freedom simulation air flotation test system and a method for positioning a motion platform thereof. The system includes a base, a motion platform, a distance measurement unit, an angle measurement unit and a calculation unit. A coordinate system is set with the center point of the upper surface of the base as the coordinate origin. The motion platform is installed on the base, the power is turned on, the system is initialized, two position points are selected at the edge of the base, wherein the center point of the motion platform is perpendicular to the line between the two selected position points, the distance measurement unit obtains the first distance and the second distance between the center point of the motion platform and the first position point and the second position point on the edge of the base respectively, the angle measurement unit obtains the angle between the line between the center point of the motion platform and the first position point on the edge of the base and the geomagnetic direction N, and the calculation unit calculates the position coordinates of the center point of the motion platform in the plane rectangular coordinate system according to the first distance, the second distance and the angle. The method and system are simple to set up and can accurately position the motion platform.

Description

Technical Field

[0001] The invention relates to the technical field of spacecraft ground physics simulation, and in particular to a three-degree-of-freedom simulation air flotation test system and a motion platform positioning method thereof. Background Art

[0002] The air-floating platform relies on compressed air to form an air film between the air-floating bearing and the bearing seat, so that the air-floating platform floats and achieves a relative motion condition that is nearly frictionless, so as to simulate the environment of small disturbance torques that the satellite is subjected to in outer space. As a satellite motion simulator, full / semi-physical simulation through the air-floating platform plays an important role. It is an indispensable tool for program demonstration and function verification. Simulation practice has proved that simulation using the air-floating platform not only plays an important role in the verification of satellite attitude control systems, but also can significantly improve the cost-effectiveness of satellites, reduce risks, and shorten the R&D cycle.

[0003] During the simulation process, it is necessary to accurately locate the position of the motion platform installed in the three-degree-of-freedom simulation air flotation test system to meet the simulation requirements. Most of the existing positioning methods use visual technology, but this technology has complex calculation methods and expensive equipment. A simple and inexpensive positioning method is needed to accurately locate the motion platform on the plane of the three-degree-of-freedom simulation air flotation test system. Summary of the invention

[0004] In order to reduce detection costs and improve positioning accuracy, the present invention application proposes a three-degree-of-freedom simulation air flotation test system and a motion platform positioning method thereof. The motion platform is positioned based on the base on the three-degree-of-freedom simulation air flotation test system, and the calculation method is simple and reliable.

[0005] On the one hand, the present invention provides a method for positioning a motion platform in a three-degree-of-freedom simulation air flotation test system, comprising the following steps:

[0006] S1. Set a plane rectangular coordinate system with the center point of the upper surface of the base of the three-degree-of-freedom simulation air flotation test system as the coordinate origin, where the positive direction of the x-axis is the same as the geomagnetic direction N;

[0007] S2. Install the motion platform on the base of the three-degree-of-freedom simulation air flotation test system, turn on the power, and initialize the system;

[0008] S3, randomly select two position points on the edge of the base, where the center point of the motion platform is perpendicular to the line connecting the two position points selected on the edge of the base, and obtain the first distance between the center point of the motion platform and the first position point and the second position point on the edge of the base respectively and the second distance ;

[0009] S4. Obtain the angle between the line connecting the center point of the motion platform and the first position point on the edge of the base and the geomagnetic direction N ;

[0010] S5. According to the first distance , Second distance And the angle Calculate the position coordinates of the center point of the motion platform in the plane rectangular coordinate system.

[0011] Preferably, the cross-sections of the base and the motion platform of the three-degree-of-freedom simulation air flotation test system in S1 are both circular, and the specific process of S3 is as follows:

[0012] S31, selecting a third position point and a fourth position point from the motion platform, specifically, taking the intersection of the line connecting the center point of the motion platform and the first position point and the second position point on the edge of the base and the edge of the motion platform as the third position point and the fourth position point;

[0013] S32, installing the first position measurement unit and the second position measurement unit at the third position point and the fourth position point on the motion platform respectively, and setting the baffle ring at the first position point and the second position point on the edge of the circular base;

[0014] S33, measuring a third distance between a third position point on the motion platform and a first position point on the edge of the base according to the first position measurement unit and the baffle , measuring a fourth distance between a fourth position point on the motion platform and a second position point on the edge of the base according to the second position measurement unit and the baffle ;

[0015] S34, calculating the first distances between the center point of the motion platform and the first position point and the second position point on the edge of the base respectively according to the third distance, the fourth distance and the radius of the motion platform and the second distance .

[0016] Preferably, the first position measurement unit and the second position measurement unit in S32 are specifically a first laser rangefinder and a second laser rangefinder, and the lasers emitted by the first laser rangefinder and the second laser rangefinder are perpendicular to each other.

[0017] Preferably, the position coordinates of the center point of the motion platform in S5 in the plane rectangular coordinate system are specifically expressed as:

[0018] ;

[0019] ;

[0020] in, ;

[0021] ;

[0022] , ;

[0023] In the formula, Indicates the position coordinate of the center point of the motion platform on the x-axis. Indicates the position coordinate of the center point of the motion platform on the y-axis. , are process variables, It represents the third distance between the third position point on the motion platform and the first position point on the edge of the base. represents the fourth distance between the fourth position point on the motion platform and the second position point on the edge of the base, is the radius of the base, is the radius of the motion platform, Indicates the first distance between the center point of the motion platform and the first position point on the edge of the base , Indicates the second distance between the center point of the motion platform and the second position point on the edge of the base, It represents the angle between the line between the center point of the motion platform and the first position point on the edge of the base and the geomagnetic direction N.

[0024] Another aspect of the present invention provides a three-degree-of-freedom simulated air flotation test system, wherein the motion platform is positioned using the motion platform positioning method of the three-degree-of-freedom simulated air flotation test system, and the three-degree-of-freedom simulated air flotation test system comprises:

[0025] A base, a motion platform, a distance measuring unit, an angle measuring unit and a calculation unit. The motion platform is mounted on the base, the distance measuring unit and the angle measuring unit are mounted on the motion platform, and the distance measuring unit and the angle measuring unit are connected to the calculation unit respectively, wherein:

[0026] The distance measuring unit is used to measure the first distance information between the center point of the motion platform and the first position of the edge of the base, and is also used to measure the second distance information between the center point of the motion platform and the second position of the edge of the base;

[0027] The angle measurement unit is used to measure the angle information between the line between the center point of the motion platform and the first position of the base edge and the geomagnetic direction N;

[0028] The calculation unit is used to receive the first distance information, the second distance information and the angle information and calculate the position information of the center point of the motion platform.

[0029] Preferably, the cross-section of the base and the motion platform is circular, the distance measuring unit includes a first laser rangefinder, a second laser rangefinder and a baffle, the first laser rangefinder and the second laser rangefinder are respectively fixed on the edge of the motion platform and the lasers emitted are perpendicular to each other, and the baffle is arranged on the edge of the base for receiving the lasers emitted by the first laser rangefinder and the second laser rangefinder.

[0030] Preferably, the angle measurement unit includes an electronic compass and a gyroscope.

[0031] Preferably, the three-degree-of-freedom simulated air flotation test system further includes a frame body 5 and a leveling pad 6 , wherein the leveling pad 6 is disposed at the lower end of the frame body 5 , and the base 1 is installed above the frame body 5 .

[0032] The above-mentioned three-degree-of-freedom simulation air flotation test system and its motion platform positioning method, the three-degree-of-freedom simulation air flotation test system includes a base, a motion platform, a distance measurement unit, an angle measurement unit and a calculation unit, a plane rectangular coordinate system is set with the center point of the upper surface of the base as the coordinate origin, wherein the positive direction of the x-axis is the same as the geomagnetic direction N, the motion platform is installed on the base of the three-degree-of-freedom simulation air flotation test system, the power is turned on, the system is initialized, two position points are randomly selected at the edge of the base, wherein the line between the center point of the motion platform and the two position points selected on the edge of the base is perpendicular, the first distance and the second distance between the center point of the motion platform and the first position point and the second position point on the edge of the base are obtained by the distance measurement unit, the angle between the line between the center point of the motion platform and the first position point on the edge of the base and the geomagnetic direction N is obtained by the angle measurement unit, and the calculation unit calculates the position coordinates of the center point of the motion platform in the plane rectangular coordinate system according to the first distance, the second distance and the angle. The method and system are simple to set up and can realize accurate positioning of the test piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flow chart of a method for positioning the center of a motion platform of a three-degree-of-freedom simulation air flotation test system in one embodiment of the present invention;

[0034] Figure 2 It is a schematic diagram of positioning of a motion platform in one embodiment of the present invention.

[0035] Figure 3 It is a schematic diagram of intermediate process variables A and B during positioning of a motion platform in one embodiment of the present invention.

[0036] Figure 4 It is a partial structural diagram of a three-degree-of-freedom simulation air flotation test system.

[0037] Description of reference numerals:

[0038] 1. Base;

[0039] 2. Sports platform;

[0040] 3. Distance measurement unit; 31. First laser rangefinder; 32. Second laser rangefinder; 33. Baffle;

[0041] 4. Angle measurement unit;

[0042] 5. Frame

[0043] 6. Level the foot pads. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings.

[0045] See also Figure 1 A motion platform positioning method for a three-degree-of-freedom simulation air flotation test system comprises the following steps:

[0046] S1. Set a plane rectangular coordinate system with the center point of the upper surface of the base of the three-degree-of-freedom simulation air flotation test system as the coordinate origin, where the positive direction of the x-axis is the same as the geomagnetic direction N.

[0047] S2. Install the motion platform on the base of the three-degree-of-freedom simulation air flotation test system, turn on the power, and initialize the system.

[0048] Specifically, the three-degree-of-freedom simulation air flotation test system refers to a uniaxial air flotation platform whose motion platform can rotate around the z-axis and / or a translational air flotation platform whose motion platform can move along the xy plane. Based on the three-degree-of-freedom simulation air flotation test system, the center point of the upper base is taken as the origin o, the positive direction of the x-axis is set to be the same as the geomagnetic direction N and a plane rectangular coordinate system is constructed, in which the plane where xoy is located is parallel to the mounting surface of the base, and the motion platform is installed on the base mounting surface of the three-degree-of-freedom simulation air flotation test system. The cross-section of the base and the motion platform can be regular shapes such as circular, square, rectangular, etc. In order to facilitate processing and calculation, the cross-section of the base and the motion platform is set to circular in this implementation.

[0049] S3. Select two points at random on the edge of the base. and , where the center point of the motion platform and two position points selected on the edge of the base and The lines between them are perpendicular, and the center point of the motion platform is obtained respectively from the first position point on the edge of the base and the second location point The first distance between and the second distance .

[0050] Furthermore, the specific process of S3 is as follows:

[0051] S31. Select the third position point from the motion platform and the fourth position point Specifically, the center point of the motion platform is aligned with the first position point on the edge of the base. and the second location point The intersection of the line connecting the moving platform and the edge of the moving platform is taken as the third position point and the fourth position point .

[0052] S32, respectively installing the first position measurement unit and the second position measurement unit at a third position point on the motion platform and the fourth position point , set the baffle ring at the first position point on the edge of the circular base and the second location point Place.

[0053] Furthermore, in S32, the first position measurement unit and the second position measurement unit are specifically a first laser rangefinder and a second laser rangefinder, and the first laser rangefinder and the second laser rangefinder are respectively installed at a third position point on the motion platform. and the fourth position point , and in order to facilitate measurement and subsequent calculation, the lasers emitted by the first laser rangefinder and the second laser rangefinder are set to be perpendicular to each other. When the first position measurement unit and the second position measurement unit are specifically the first laser rangefinder and the second laser rangefinder, the baffle is used to receive the lasers emitted by the first laser rangefinder and the second laser rangefinder.

[0054] S33, measuring the third position point on the motion platform according to the first position measurement unit and the baffle and the first position point on the edge of the base The third distance between , measure the fourth position point on the motion platform according to the second position measurement unit and the baffle and the second position point on the edge of the base The fourth distance between .

[0055] S34, according to the third distance , the fourth distance And the radius of the motion platform Calculate the center point of the motion platform and the first position point on the edge of the base and the second location point The first distance between and the second distance .

[0056] S4. Obtain the center point of the motion platform and the first position point on the edge of the base The angle between the line between ;

[0057] S5. According to the first distance , Second distance And the angle Calculate the position coordinates of the center point of the motion platform in the plane rectangular coordinate system.

[0058] Further, see Figure 2 , the position coordinates of the center point of the motion platform in S5 in the plane rectangular coordinate system are specifically expressed as:

[0059] ;

[0060] ;

[0061] in, ;

[0062] ;

[0063] , ;

[0064] In the formula, Indicates the position coordinate of the center point of the motion platform on the x-axis. Indicates the position coordinate of the center point of the motion platform on the y-axis. , are process variables, Indicates the third position point on the motion platform and the first position point on the edge of the base The third distance between Indicates the fourth position point on the motion platform and the second position point on the edge of the base The fourth distance between is the radius of the base, is the radius of the motion platform, Indicates the center point of the motion platform and the first position point on the edge of the base The first distance between , Indicates the center point of the motion platform and the second position point on the edge of the base The second distance between Indicates the center point of the motion platform and the first position point on the edge of the base The angle between the line connecting them and the geomagnetic direction N. The process variables A and B are described as follows:

[0065] See also Figure 3 , rotate the motion platform around the coordinate origin until the center point of the motion platform and the first position point on the edge of the base are aligned The angle between the line connecting them and the geomagnetic direction N (that is, the positive direction of the x-axis) When it is 0, the position of the center of the motion platform on the xoy plane, where A is the x-axis coordinate and B is the y-axis coordinate.

[0066] In the above parameters, if the motion platform rotates during the test, Will change with the rotation of the motion platform. If the motion platform moves during the test, and It will change as the motion platform moves.

[0067] In addition, for three-axis air-floating platforms or five-DOF air-floating platforms, the pitch / roll angle is optimized to eliminate the angle between the two After the influence of , the above method can also be applied to the motion platform positioning of a three-axis air-floating table or a five-degree-of-freedom air-floating table.

[0068] In another embodiment, see Figure 4 A three-degree-of-freedom simulated air flotation test system, using the above method to position a motion platform installed thereon, the three-degree-of-freedom simulated air flotation test system comprising:

[0069] Base 1, motion platform 2, distance measuring unit 3, angle measuring unit 4 and calculation unit, the motion platform 2 is mounted on the base 1, the distance measuring unit 3 and the angle measuring unit 4 are mounted on the motion platform 2, the distance measuring unit 3 and the angle measuring unit 4 are connected to the calculation unit respectively, wherein:

[0070] The distance measuring unit 3 is used to measure the first distance information between the center point of the motion platform 2 and the first position of the edge of the base 1, and is also used to measure the second distance information between the center point of the motion platform 2 and the second position of the edge of the base 1;

[0071] The angle measurement unit 4 is used to measure the angle information between the line between the center point of the motion platform 2 and the first position of the edge of the base 1 and the geomagnetic direction N;

[0072] The calculation unit is used to receive the first distance information, the second distance information and the angle information and calculate the position information of the center point of the motion platform 2.

[0073] In order to reduce the detection cost and facilitate the calculation of the center position of the motion platform 2, as a further improvement, the cross-section of the base 1 and the motion platform 2 is circular, and the distance measurement unit 3 includes a first laser rangefinder 31, a second laser rangefinder 32 and a baffle 33. The first laser rangefinder 31 and the second laser rangefinder 32 are respectively fixed on the edge of the motion platform 2 and the emitted lasers are perpendicular to each other. The baffle 33 is installed on the edge of the base 1 for receiving the lasers emitted by the first laser rangefinder 31 and the second laser rangefinder 32.

[0074] Furthermore, the angle measurement unit includes an electronic compass and a gyroscope. The angle information between the line between the first position on the motion platform 2 and the first position on the edge of the base 1 and the geomagnetic direction N obtained by the gyroscope mainly contains low-frequency noise (zero bias, cumulative error), and the angle information between the line between the first position on the motion platform 2 and the first position on the edge of the base 1 and the geomagnetic direction N obtained by the electronic compass mainly contains high-frequency noise. The angle information obtained by the electronic compass and the gyroscope are complementary filtered, and the fused information obtained after filtering is used as the angle information between the line between the first position on the motion platform 2 and the first position on the edge of the base 1 and the geomagnetic direction N.

[0075] Furthermore, the three-degree-of-freedom simulation air flotation test system also includes a frame 5 and a leveling pad 6, the leveling pad 6 is located below the frame 5, and the base 1 is installed above the frame 5. The base 1 is adjusted by the leveling pad 6 to ensure that the installation surface of the base 1 is parallel to the horizontal plane. The number of the leveling pads 6 is three or more. Furthermore, the base 1 adopts a marble slab to ensure surface accuracy.

[0076] The above three-degree-of-freedom simulation air flotation test system also includes an air flotation device and a power device, wherein:

[0077] The air flotation device can generate gas to make the motion platform 2 float above the base 1 to simulate the state of the spacecraft in the air;

[0078] The power device is disposed on the motion platform 2 , and can generate thrust by releasing high-pressure gas to drive the motion platform 2 to move relative to the base 1 and / or to rotate the motion platform 2 .

[0079] The specific definition of a three-degree-of-freedom simulation air flotation test system can be found in the above definition of a motion platform positioning method for a three-degree-of-freedom simulation air flotation test system, which will not be repeated here.

[0080] The above-mentioned three-degree-of-freedom simulation air flotation test system and its motion platform positioning method, the three-degree-of-freedom simulation air flotation test system includes a base, a motion platform, a distance measurement unit, an angle measurement unit and a calculation unit, a plane rectangular coordinate system is set with the center point of the upper surface of the base as the coordinate origin, wherein the positive direction of the x-axis is the same as the geomagnetic direction N, the motion platform is installed on the base of the three-degree-of-freedom simulation air flotation test system, the power is turned on, the system is initialized, two position points are randomly selected at the edge of the base, wherein the line between the center point of the motion platform and the two position points selected on the edge of the base is perpendicular, the first distance and the second distance between the center point of the motion platform and the first position point and the second position point on the edge of the base are obtained by the distance measurement unit, the angle between the line between the center point of the motion platform and the first position point on the edge of the base and the geomagnetic direction N is obtained by the angle measurement unit, and the calculation unit calculates the position coordinates of the center point of the motion platform in the plane rectangular coordinate system according to the first distance, the second distance and the angle. The method and system are simple to set up and can realize accurate positioning of the test piece.

[0081] The above is a detailed introduction to a three-degree-of-freedom simulated air flotation test system and a motion platform positioning method provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A motion platform positioning method for a three-degree-of-freedom simulation air flotation test system, characterized in that: The method comprises the following steps: S1. Set a plane rectangular coordinate system with the center point of the upper surface of the base of the three-degree-of-freedom simulation air flotation test system as the coordinate origin, where the positive direction of the x-axis is the same as the geomagnetic direction N; S2. Install the motion platform on the base of the three-degree-of-freedom simulation air flotation test system, turn on the power, and initialize the system; S3, randomly select two position points on the edge of the base, where the center point of the motion platform is perpendicular to the line connecting the two position points selected on the edge of the base, and obtain the first distance between the center point of the motion platform and the first position point and the second position point on the edge of the base respectively and the second distance ; S4. Obtain the angle between the line connecting the center point of the motion platform and the first position point on the edge of the base and the geomagnetic direction N ; S5. According to the first distance , Second distance And the angle Calculate the position coordinates of the center point of the motion platform in the plane rectangular coordinate system.

2. The motion platform positioning method of the three-degree-of-freedom simulation air flotation test system according to claim 1, characterized in that: The cross-sections of the base and motion platform of the three-degree-of-freedom simulation air flotation test system in S1 are both circular. The specific process of S3 is as follows: S31, selecting a third position point and a fourth position point from the motion platform, specifically, taking the intersection of the line connecting the center point of the motion platform and the first position point and the second position point on the edge of the base and the edge of the motion platform as the third position point and the fourth position point; S32, installing the first position measurement unit and the second position measurement unit at the third position point and the fourth position point on the motion platform respectively, and setting the baffle ring at the first position point and the second position point on the edge of the circular base; S33, measuring a third distance between a third position point on the motion platform and a first position point on the edge of the base according to the first position measurement unit and the baffle , measuring a fourth distance between a fourth position point on the motion platform and a second position point on the edge of the base according to the second position measurement unit and the baffle ; S34, calculating the first distances between the center point of the motion platform and the first position point and the second position point on the edge of the base respectively according to the third distance, the fourth distance and the radius of the motion platform and the second distance .

3. The motion platform positioning method of the three-degree-of-freedom simulation air flotation test system according to claim 2, characterized in that: In S32, the first position measurement unit and the second position measurement unit are specifically a first laser rangefinder and a second laser rangefinder, and the lasers emitted by the first laser rangefinder and the second laser rangefinder are perpendicular to each other.

4. The motion platform positioning method of the three-degree-of-freedom simulation air flotation test system according to claim 3, characterized in that: The position coordinates of the center point of the motion platform in S5 in the plane rectangular coordinate system are specifically expressed as: ； ； in, ; ； ， ； In the formula, Indicates the position coordinate of the center point of the motion platform on the x-axis. Indicates the position coordinate of the center point of the motion platform on the y-axis. , are process variables, It represents the third distance between the third position point on the motion platform and the first position point on the edge of the base. represents the fourth distance between the fourth position point on the motion platform and the second position point on the edge of the base, is the radius of the base, is the radius of the motion platform, Indicates the first distance between the center point of the motion platform and the first position point on the edge of the base , Indicates the second distance between the center point of the motion platform and the second position point on the edge of the base, It represents the angle between the line between the center point of the motion platform and the first position point on the edge of the base and the geomagnetic direction N.

5. A three-degree-of-freedom simulated air flotation test system, using the method according to any one of claims 1 to 4 to position the motion platform, characterized in that: The three-degree-of-freedom simulation air flotation test system comprises: A base (1), a motion platform (2), a distance measuring unit (3), an angle measuring unit (4) and a computing unit, wherein the motion platform (2) is mounted on the base (1), the distance measuring unit (3) and the angle measuring unit (4) are mounted on the motion platform (2), and the distance measuring unit (3) and the angle measuring unit (4) are respectively connected to the computing unit, wherein: The distance measuring unit (3) is used to measure first distance information between the center point of the motion platform (2) and a first position of the edge of the base (1), and is also used to measure second distance information between the center point of the motion platform (2) and a second position of the edge of the base (1); The angle measurement unit (4) is used to measure the angle information between the line between the center point of the motion platform (2) and the first position of the edge of the base (1) and the geomagnetic direction N; The calculation unit is used to receive the first distance information, the second distance information and the angle information and calculate the position information of the center point of the motion platform (2).

6. The three-degree-of-freedom simulated air flotation test system according to claim 5, characterized in that: The cross-sections of the base (1) and the motion platform (2) are circular. The distance measuring unit (3) comprises a first laser rangefinder (31), a second laser rangefinder (32) and a baffle (33). The first laser rangefinder (31) and the second laser rangefinder (32) are respectively fixed to the edge of the motion platform (2) and the laser beams emitted by them are perpendicular to each other. The baffle (33) is arranged around the edge of the base (1) and is used to receive the laser beams emitted by the first laser rangefinder (31) and the second laser rangefinder (32).

7. The three-degree-of-freedom simulated air flotation test system according to claim 6, characterized in that: The angle measurement unit (4) includes an electronic compass and a gyroscope.

8. The three-degree-of-freedom simulated air flotation test system according to claim 7, characterized in that: It also includes a frame (5) and a leveling pad (6), wherein the leveling pad (6) is arranged at the lower end of the frame (5), and the base (1) is installed above the frame (5).

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