Air floatation simulator automatic leveling device and control method

Abstract

The invention relates to an automatic leveling device for an air floatation simulator and a control method. Three air floatation bearings distributed in a triangular shape are mounted at the bottom of the air floatation simulator; the cross-shaped sliding table is arranged on the middle layer of the air floatation simulator, is used for driving the weight to perform two-axis movement in the horizontal direction, and comprises an X-direction guide rail and a Y-direction guide rail which are orthogonally overlapped; the two servo motors drive the X-direction guide rail and the Y-direction guide rail to move and drive the weights to move. The controller controls the two servo motors and samples the weight values of the three weighing sensors in real time; the three weighing sensors are installed on the three air bearings respectively, the mass center of the air floating simulator is adjusted by adjusting the positive and negative rotation and the speed ratio of the two servo motors, and when the cross-shaped sliding table makes the weights of the three weighing sensors consistent through planar motion, leveling of the air floating simulator is completed. The problems that an existing leveling method is long in adjusting time, poor in stability, low in feedback speed and the like are solved, and the method can be conveniently transplanted to other air flotation simulators.

Description

Technical Field

[0001] This invention belongs to the field of microgravity simulation technology and relates to an automatic leveling device and control method for an air flotation simulator. Background Technology

[0002] Ground-based microgravity simulation for space separation missions is a crucial step, serving as a design reference before the mission and enabling post-mission simulation analysis. A key step in ground-based microgravity simulation is leveling the air-bearing simulator to prevent lateral forces from affecting the separation simulation results. Currently, research on air-bearing separation experiments is limited, and methods for leveling the air-bearing simulator are not yet fully developed.

[0003] Based on the research of existing technologies, the following relevant technical documents exist:

[0004] The paper "Design and Application of a Self-Leveling System Based on Air Flotation Technology" by Tian Fang describes the design of a sophisticated leveling hardware system. Its drawback is that it is entirely hardware-based and cannot be leveled via software, making it difficult to adapt to different working conditions.

[0005] The paper "Design, Construction, and Center of Gravity Leveling of a Satellite Triaxial Air-Float Test Rig" by Zheng Haolin presents a BP-PID method for leveling the center of gravity of a triaxial air-float test rig, achieving a leveling accuracy typically above one percent. However, the BP-PID method is sensitive to parameters, limiting its stability.

[0006] "Automatic Balancing Methods for a Three-Axis Air-Float Simulator," by Xiang Dong, presents two automatic balancing methods. The first method, based on the motion model of the three-axis air-float simulator, derives the equation for eccentricity through dynamic inversion, providing the solution and formula for calculating eccentricity error. The second method estimates eccentricity using the period based on compound pendulum theory and calculates and adjusts the x and y axis offsets based on the tilt angle at the zero acceleration point. Experimental results show that both methods effectively reduce unbalanced torque. Method one offers faster adjustment but higher cost; method two is simpler and less costly but takes longer to adjust (balancing time <10 minutes).

[0007] Patent 202311442463.9, "An Air Float Leveling Platform for Chip Flip Bonding and Its Leveling and Locking Method," is a leveling method relying on precision mechanics, utilizing flip bonding and locking actions to complete air float leveling. Its drawback is that since leveling is not software-based, the method is not easily ported to other air float simulators.

[0008] Patent 202310068093.0, "Three-Degree-of-Freedom Semi-Physical Simulation System and Its Working Method," describes a three-degree-of-freedom semi-physical simulation system and its working method. A three-axis air-bearing platform is mounted on a support frame. High-pressure gas lubrication provided by the air-bearing support allows the air-bearing hemisphere to freely roll and rotate within the ball socket of the support. An attitude control system is mounted on a test platform, which rotates on a transition plate positioned at the stop of the air-bearing hemisphere. A limit protection device includes a limit ring located below the transition plate and surrounding the air-bearing hemisphere. The movement of the limit ring prevents the test platform from exceeding a set angle. An automatic leveling device is located below the side of the test platform, and its control box is mounted on the platform. The automatic leveling device uses a motor controller to control the rotation of a servo motor, which in turn moves the weights on the slider to achieve leveling. Simultaneously, the control box contains an inclinometer to detect the swing angle of the test platform. The drawback is the use of an expensive inclinometer as the leveling feedback signal, and the inclinometer's feedback speed is slow, requiring 200ms to update data. Summary of the Invention

[0009] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose an automatic leveling device and control method for an air flotation simulator. This solves the problems of long adjustment time, poor stability and slow feedback speed of the existing air flotation platform leveling method. It is implemented by software and can be easily ported to other air flotation simulators.

[0010] The solution to the technical problem of the present invention is: an automatic leveling device for an air flotation simulator, comprising an air flotation simulator, a cross slide, weights, a controller, two servo motors and three weighing sensors;

[0011] The air flotation simulator is equipped with three air flotation bearings at the bottom, and the three air flotation bearings are distributed in a triangular shape in the planar space.

[0012] The cross slide is placed in the middle layer of the air flotation simulator and is used to drive the weight to move horizontally along two axes. The cross slide includes two orthogonally stacked guide rails, each of which is equipped with a slider. The lower guide rail is called the X guide rail and the upper guide rail is called the Y guide rail. The Y guide rail moves along the X guide rail axis through the slider on the X guide rail. The weight is placed on the slider of the Y guide rail and moves along the Y guide rail axis with the slider.

[0013] The two servo motors are respectively installed at the ends of the X-axis guide rail and the Y-axis guide rail, and are used to drive the guide shafts of the X-axis guide rail and the Y-axis guide rail to rotate, thereby converting them into linear motion of the slider and driving the weight to move.

[0014] The controller controls two servo motors to drive the two axes of the cross slide table through communication, and samples the weight values ​​of three weighing sensors in real time.

[0015] The three load cells are respectively installed on the three air bearings of the air flotation simulator. The weight values ​​of the load cells serve as feedback for automatic leveling. The center of gravity of the air flotation simulator is adjusted by adjusting the forward and reverse rotation and speed ratio of the two servo motors. When the cross slide moves in a planar motion so that the weights of the three load cells are consistent, the leveling of the air flotation simulator is completed.

[0016] Furthermore, the servo motor installed at the end of the X-axis guide rail is defined as the X-axis servo motor, and the servo motor installed at the end of the Y-axis guide rail is defined as the Y-axis servo motor. Two of the three load cells are located on the same side of the X-axis guide rail, and are defined as load cell 1 and load cell 2. The other load cell is located on the other side of the X-axis guide rail and is defined as load cell 3.

[0017] The forward rotation of the X-axis servo motor moves the weight in the positive X-axis direction, making weighing sensor #2 heavier, weighing sensor #1 lighter, and weighing sensor #3 either heavier or lighter, with the magnitude of the change being smaller than that of weighing sensors #1 and #2. The reverse rotation of the X-axis servo motor moves the weight in the negative X-axis direction, making weighing sensor #1 heavier, weighing sensor #2 lighter, and weighing sensor #3 either heavier or lighter, with the magnitude of the change being smaller than that of weighing sensors #1 and #2.

[0018] The forward rotation of the Y-axis servo motor moves the weight in the positive Y-axis direction, making weighing sensors 1 and 2 heavier and weighing sensor 3 lighter; the reverse rotation of the Y-axis servo motor moves the weight in the negative Y-axis direction, making weighing sensor 3 heavier and weighing sensors 1 and 2 lighter.

[0019] Furthermore, the weight of the weight is greater than 50% of the weight of the air flotation simulator.

[0020] An automatic leveling control method for an air flotation simulator includes the following steps:

[0021] Calculate the coordinates of the center of mass of the air-bearing simulator before and after the cross slide moves the weight. Let the coordinates of the center of mass before the movement be (x1, y1) and the coordinates of the center of mass after the movement be (x2, y2).

[0022] Two servo motors drive the weight to move towards the third weighing sensor along a direction perpendicular to the line connecting the first and second weighing sensors. To ensure the weight remains vertical due to the combined motion of the X and Y guide rails, the speed ratio of the X-axis servo motor to the Y-axis servo motor is maintained at a constant value.

[0023] When the weight moves to a point where the weight of the No. 3 weighing sensor is one-third of the total mass M, the two servo motors stop; M = (m A+ m B+ m C ), mA m B m C These are the weight values ​​of weighing sensor 1, weighing sensor 2, and weighing sensor 3, respectively.

[0024] Read the weight values ​​of weighing sensors 1 and 2. If weighing sensor 1 is lighter, drive the weight to move towards weighing sensor 1 along a line parallel to the line connecting weighing sensors 1 and 2. The speed ratio of the X-axis servo motor to the Y-axis servo motor remains constant. If the second weighing sensor is lighter, the driving weight moves towards the second weighing sensor along a direction parallel to the line connecting the first and second weighing sensors. The speed ratio of the X-axis servo motor to the Y-axis servo motor remains constant.

[0025] When the weight moves to the point where the weight values ​​of weighing sensor 1 and weighing sensor 2 are equal, the two servo motors stop, and the air flotation simulator is leveled.

[0026] Furthermore, the method for calculating the centroid coordinates of the air-float simulator is as follows:

[0027] In the planar triangle formed by the three weighing sensors, let the vertices corresponding to weighing sensors 1, 2, and 3 be A, B, and C, respectively, and the lengths of their opposite sides be a, b, and c. The formula for calculating the centroid of the air flotation simulator is:

[0028]

[0029] Where r → A ,r → B ,r → C M is the position vector of vertices A, B, and C, where M = m A +m B +m C It is the total mass of the three weighing sensors;

[0030] To calculate the specific coordinates of the centroid, a coordinate system is established as follows: vertex A is the origin (0, 0), vertex B is located at (c, 0), and the coordinates of vertex C are (x, y). C ,y C The solution is obtained by using the side length as follows:

[0031] From the cosine quantification, we can obtain:

[0032] From the distance formula, we can obtain:

[0033] r →A =(0,0),r → B =(c,0),r → C =(x C ,y C Substitute into the centroid calculation formula R cm → Calculate the centroid coordinates (x) g ,y g )for

[0034] Furthermore, the fluctuation threshold is set to 0.5‰ of the total mass M. When the weight difference between weighing sensor 1 and weighing sensor 2 is less than the fluctuation threshold, it is determined that the weight values ​​of weighing sensor 1 and weighing sensor 2 are equal.

[0035] The advantages of this invention compared to the prior art are:

[0036] (1) The present invention provides an automatic leveling device and control method for an air-float simulator. By combining a cross slide and a weighing sensor, the air-float simulator is leveled in a way that adapts to the motion of the center of mass. The weighing sensor installed on the three-phase air-float bearing serves as feedback to adjust the large mass weight driven by the cross slide in planar motion to achieve automatic leveling. By controlling the speed ratio of the motor to adjust the direction of movement of the cross slide, the three weighing sensors are quickly, accurately, and efficiently adjusted to have the same load, thus completing the automatic leveling process of the air-float platform.

[0037] (2) This invention realizes an automated leveling process, which comprehensively improves the accuracy of the space separation ground test, with a leveling accuracy of <4‰.

[0038] (3) The present invention does not require knowledge of the positional relationship between the ten-fixed slide and the weighing sensor, which greatly simplifies the design and construction of the leveling mechanism.

[0039] (4) The present invention uses a centroid motion method based on process regulation, which is equivalent to the feedforward value in closed-loop control, to eliminate the oscillation of closed-loop regulation and achieve rapid convergence.

[0040] (5) The present invention uses a weighing sensor with faster feedback speed and uses centroid kinematics calculation, which improves the leveling time to <3 minutes. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the air flotation simulator of the present invention;

[0042] Figure 2 This is a schematic diagram of the cross slide and weights of the present invention;

[0043] Figure 3This is a schematic diagram illustrating the automatic leveling control principle of the air flotation platform of the present invention.

[0044] Figure 4 This is a flowchart of the automatic leveling control method for the air flotation platform of the present invention. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] Example 1

[0047] like Figure 1 As shown, the present invention first proposes an automatic leveling device for an air flotation simulator, including an air flotation simulator, a cross slide, weights, a controller, two servo motors and three weighing sensors;

[0048] The air buoyancy simulator is able to move under microgravity on a marble platform. Three air buoyancy bearings are installed at the bottom, and the three air buoyancy bearings are distributed in a triangular pattern in planar space.

[0049] A cross slide is placed in the middle layer of the air flotation simulator to drive the weight in horizontal two-axis motion. The cross slide includes two orthogonally stacked guide rails, each with a slider. The lower guide rail is designated as the X-rail, and the upper guide rail as the Y-rail. The Y-rail moves along the X-rail axis via the slider on the X-rail. The weight is placed on the slider of the Y-rail and moves along the Y-rail axis with it. Figure 2 As shown;

[0050] Two servo motors are installed at the ends of the X-axis guide rail and the Y-axis guide rail, respectively, to drive the guide shafts of the X-axis guide rail and the Y-axis guide rail to rotate, which is then converted into linear motion of the slider, thereby moving the weight.

[0051] The controller uses 485 communication to control two servo motors to drive the two axes of the cross slide table and samples the weight values ​​of three weighing sensors in real time.

[0052] Three load cells are installed on the three air bearings of the air flotation simulator. The weight values ​​of the load cells serve as feedback for automatic leveling. The center of gravity of the air flotation simulator is adjusted by changing the forward and reverse rotation and speed ratio of the two servo motors. When the cross slide moves in a planar motion and makes the weights of the three load cells consistent, the air flotation simulator is leveled.

[0053] The servo motor mounted on the end of the X-axis guide rail is defined as the X-axis servo motor, and the servo motor mounted on the end of the Y-axis guide rail is defined as the Y-axis servo motor. Two of the three load cells are located on the same side of the X-axis guide rail, defined as load cell 1 and load cell 2, and the third load cell is located on the other side of the X-axis guide rail, defined as load cell 3. Figure 3 As shown.

[0054] The forward rotation of the X-axis servo motor moves the weight in the positive X-axis direction, making load cell #2 heavier and load cell #1 lighter. Load cell #3 may also become heavier or lighter depending on its position, with a smaller fluctuation than load cells #1 and #2. The reverse rotation of the X-axis servo motor moves the weight in the negative X-axis direction, making load cell #1 heavier and load cell #2 lighter. Load cell #3 may also become heavier or lighter depending on its position, with a smaller fluctuation than load cells #1 and #2. Similarly, the forward rotation of the Y-axis servo motor moves the weight in the positive Y-axis direction, making load cells #1 and #2 heavier and load cell #3 lighter. The reverse rotation of the Y-axis servo motor moves the weight in the negative Y-axis direction, making load cell #3 heavier and load cells #1 and #2 lighter. The control principle is to control the forward and reverse rotation of the two motors based on the feedback values ​​from the three load cells according to the above rules, ultimately making the values ​​of the three load cells the same, thus leveling the air flotation platform. The leveling control method is a closed-loop control method. The feedback is the values ​​of three weighing sensors. This process is an angle self-identification process, which does not require knowing the specific coordinate positions of the weighing sensors.

[0055] The weight is a large mass block, weighing more than 50% of the weight of the air flotation simulator.

[0056] Based on the above-mentioned leveling device, the present invention also proposes an automatic leveling control method for an air flotation simulator, such as... Figure 4 As shown, it includes the following steps:

[0057] S1. Calculate the coordinates of the center of mass of the air-float simulator before and after the cross slide moves the weight. Let the coordinates of the center of mass before the movement be (x1, y1) and the coordinates of the center of mass after the movement be (x2, y2).

[0058] like Figure 4 As shown, the angle between the X-axis guide rail of the cross slide and the line connecting "Weighing Sensor No. 1 - Weighing Sensor No. 2" is:

[0059] S2. Two servo motors drive the weight to move towards the third weighing sensor along a direction perpendicular to the line connecting the first and second weighing sensors. To ensure the weight remains vertical due to the combined motion of the X and Y guide rails, the speed ratio of the X-axis servo motor to the Y-axis servo motor is maintained at a certain value. This ensures that the weight moves toward number 3 at angle θ in S1.

[0060] S3. When the weight moves to a point where the weight of the No. 3 weighing sensor is one-third of the total mass M, the two servo motors stop; M = (m A+ m B+ m C ), m A mB m C These are the weight values ​​of weighing sensor 1, weighing sensor 2, and weighing sensor 3, respectively.

[0061] S4. Read the weight values ​​of weighing sensors 1 and 2. If weighing sensor 1 is lighter, drive the weight to move towards weighing sensor 1 along the line parallel to the line connecting weighing sensors 1 and 2. The speed ratio of the X-axis servo motor to the Y-axis servo motor remains constant. If the second weighing sensor is lighter, the driving weight moves towards the second weighing sensor along a direction parallel to the line connecting the first and second weighing sensors. The speed ratio of the X-axis servo motor to the Y-axis servo motor remains constant.

[0062] S5. When the weight moves to the point where the weight values ​​of weighing sensor 1 and weighing sensor 2 are equal, the two servo motors stop, and the air flotation simulator is leveled.

[0063] In step S1, the method for calculating the centroid coordinates of the air flotation simulator is as follows:

[0064] In the planar triangle formed by the three weighing sensors, let the vertices corresponding to weighing sensors 1, 2, and 3 be A, B, and C, respectively, and the lengths of their opposite sides be a, b, and c. The formula for calculating the centroid of the air flotation simulator is:

[0065]

[0066] Where r → A ,r → B ,r → C M is the position vector of vertices A, B, and C, where M = m A +m B +m C It is the total mass of the three weighing sensors.

[0067] To calculate the specific coordinates of the centroid, a coordinate system is established as follows: vertex A is the origin (0, 0), vertex B is located at (c, 0), and the coordinates of vertex C are (x, y). C ,y C Solving by side length:

[0068] From the cosine quantification, we can obtain:

[0069] From the distance formula, we can obtain:

[0070] r → A=(0,0),r → B =(c,0),r → C =(x C ,y C Substitute into the centroid calculation formula R cm → Calculate the centroid coordinates (x) g ,y g )for

[0071] In step S5, a fluctuation threshold is set. This threshold is set so that when the weight values ​​of weighing sensors 1 and 2 are equal, the two servo motors stop. Since the measured weight values ​​are unlikely to be exactly the same, there will be some measurement fluctuation. In step S5, a small difference is set as a threshold when determining if the two values ​​are equal. Here, it is set to 0.5‰ of the total mass M as the threshold for equality judgment. Therefore, when judging if the weights are equal, as long as the weight difference is less than this threshold, the weights are considered equal.

[0072] The centroid motion method used in this invention is equivalent to the feedforward value in closed-loop control, which can eliminate the oscillation of closed-loop regulation and achieve rapid convergence.

[0073] The leveling accuracy of the method of this invention is related to the accuracy of the load cell and the servo motor. The accuracy of industrial-grade load cells is generally above 0.1%, and the motion accuracy of servo motors is below millimeters, so the overall leveling accuracy can reach above 0.1%.

[0074] In this embodiment, after the above leveling process, the total leveling time is 2 minutes and 30 seconds. After leveling, the weight difference of the weighing sensor is less than 0.05% of the total weight, achieving an accuracy of not less than 0.1%.

[0075] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0076] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. An automatic leveling device for an air flotation simulator, characterized in that, It includes an air flotation simulator, a cross slide, weights, a controller, two servo motors, and three weighing sensors; The air flotation simulator is equipped with three air flotation bearings at the bottom, and the three air flotation bearings are distributed in a triangular shape in the planar space. The cross slide is placed in the middle layer of the air flotation simulator and is used to drive the weight to move horizontally along two axes. The cross slide includes two orthogonally stacked guide rails, each of which is equipped with a slider. The lower guide rail is called the X guide rail and the upper guide rail is called the Y guide rail. The Y guide rail moves along the X guide rail axis through the slider on the X guide rail. The weight is placed on the slider of the Y guide rail and moves along the Y guide rail axis with the slider. The two servo motors are respectively installed at the ends of the X-axis guide rail and the Y-axis guide rail, and are used to drive the guide shafts of the X-axis guide rail and the Y-axis guide rail to rotate, thereby converting them into linear motion of the slider and driving the weight to move. The controller controls two servo motors to drive the two axes of the cross slide table through communication, and samples the weight values ​​of three weighing sensors in real time. The three load cells are respectively installed on the three air bearings of the air flotation simulator. The weight values ​​of the load cells serve as feedback for automatic leveling. The center of gravity of the air flotation simulator is adjusted by adjusting the forward and reverse rotation and speed ratio of the two servo motors. When the cross slide moves in a planar motion so that the weights of the three load cells are consistent, the leveling of the air flotation simulator is completed.

2. The automatic leveling device for an air flotation simulator according to claim 1, characterized in that, The servo motor installed at the end of the X-axis guide rail is defined as the X-axis servo motor, and the servo motor installed at the end of the Y-axis guide rail is defined as the Y-axis servo motor. Two of the three load cells are located on the same side of the X-axis guide rail and are defined as load cell 1 and load cell 2. The other load cell is located on the other side of the X-axis guide rail and is defined as load cell 3. The forward rotation of the X-axis servo motor moves the weight in the positive X-axis direction, making weighing sensor #2 heavier, weighing sensor #1 lighter, and weighing sensor #3 either heavier or lighter, with the magnitude of the change being smaller than that of weighing sensors #1 and #2. The reverse rotation of the X-axis servo motor moves the weight in the negative X-axis direction, making weighing sensor #1 heavier, weighing sensor #2 lighter, and weighing sensor #3 either heavier or lighter, with the magnitude of the change being smaller than that of weighing sensors #1 and #2. The forward rotation of the Y-axis servo motor moves the weight in the positive Y-axis direction, making weighing sensors 1 and 2 heavier and weighing sensor 3 lighter; the reverse rotation of the Y-axis servo motor moves the weight in the negative Y-axis direction, making weighing sensor 3 heavier and weighing sensors 1 and 2 lighter.

3. The automatic leveling device for an air flotation simulator according to claim 2, characterized in that, The weight of the weight is greater than 50% of the weight of the air flotation simulator.

4. An automatic leveling control method for an air flotation simulator based on the device described in any one of claims 2 to 3, characterized in that, Includes the following steps: Calculate the coordinates of the center of mass of the air-bearing simulator before and after the cross slide moves the weight. Let the coordinates of the center of mass before the movement be (x1, y1) and the coordinates of the center of mass after the movement be (x2, y2). Two servo motors drive the weight to move towards the third weighing sensor along a direction perpendicular to the line connecting the first and second weighing sensors. To ensure the weight remains vertical due to the combined motion of the X and Y guide rails, the speed ratio of the X-axis servo motor to the Y-axis servo motor is maintained at a constant value. When the weight moves to a point where the weight of the No. 3 weighing sensor is one-third of the total mass M, the two servo motors stop; M = (m A+ m B+ m C ), m A m B m C These are the weight values ​​of weighing sensor 1, weighing sensor 2, and weighing sensor 3, respectively. Read the weight values ​​of weighing sensors 1 and 2. If weighing sensor 1 is lighter, drive the weight to move towards weighing sensor 1 along a line parallel to the line connecting weighing sensors 1 and 2. The speed ratio of the X-axis servo motor to the Y-axis servo motor remains constant. If the second weighing sensor is lighter, the driving weight moves towards the second weighing sensor along a direction parallel to the line connecting the first and second weighing sensors. The speed ratio of the X-axis servo motor to the Y-axis servo motor remains constant. When the weight moves to the point where the weight values ​​of weighing sensor 1 and weighing sensor 2 are equal, the two servo motors stop, and the air flotation simulator is leveled.

5. The automatic leveling control method for an air flotation simulator according to claim 4, characterized in that, The method for calculating the centroid coordinates of the air flotation simulator is as follows: In the planar triangle formed by the three weighing sensors, let the vertices corresponding to weighing sensors 1, 2, and 3 be A, B, and C, respectively, and the lengths of their opposite sides be a, b, and c. The formula for calculating the centroid of the air flotation simulator is: Where r → A ,r → B ,r → C M is the position vector of vertices A, B, and C, where M = m A +m B +m C It is the total mass of the three weighing sensors; To calculate the specific coordinates of the centroid, a coordinate system is established as follows: vertex A is the origin (0, 0), vertex B is located at (c, 0), and the coordinates of vertex C are (x, y). C ,y C The solution is obtained by using the side length as follows: From the cosine quantification, we can obtain: From the distance formula, we can obtain: r → A =(0,0),r → B =(c,0),r → C =(x C ,y C Substitute into the centroid calculation formula R cm → Calculate the centroid coordinates (x) g ,y g )for 6. The automatic leveling control method for an air flotation simulator according to claim 4, characterized in that, The fluctuation threshold is set to 0.5‰ of the total mass M. When the weight difference between weighing sensor 1 and weighing sensor 2 is less than the fluctuation threshold, it is determined that the weight values ​​of weighing sensor 1 and weighing sensor 2 are equal.

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