A system and method for fast coarse adjustment of the center of mass of an air bearing table

Abstract

The application belongs to the technical field of air floating tables, and specifically discloses a system and method for rapid coarse adjustment and balance of the center of mass of an air floating table; the system comprises a pressure measurement system, a control system and an execution mechanism; the pressure measurement system comprises a base, a pressure sensor and a positioning pin, and is used for measuring the unbalance of the air floating table; the execution mechanism comprises a stepping motor, a wire clamp, copper wire and a shearing device provided with a tension sensor, and the copper wire is wound to adjust the counterweight; the control system can automatically calculate and drive the execution mechanism to work according to the sensor data, and the application also provides a method for rapid coarse adjustment and balance of the center of mass of the air floating table based on the system. The application can shorten the coarse adjustment and balance time of the air floating table from 2-3 hours to 10 minutes, solves the problems of low efficiency and poor precision of manual adjustment and balance, and significantly improves the simulation experiment efficiency of the air floating table.

Description

A system and method for rapid coarse balancing of the center of mass of an air-floating platform Technical Field

[0001] This invention relates to the field of air flotation platform technology, and specifically to a system and method for rapid coarse adjustment and balancing of the center of mass of an air flotation platform. Background Technology

[0002] With the continuous development of space exploration technology, increasingly higher demands are being placed on the high-precision simulation of the attitude motion of spacecraft in orbit under microgravity environments. As the core equipment of such semi-physical simulation systems, the performance of the air-bearing platform directly affects the credibility of the simulation experiment. However, in actual use, the air-bearing platform is affected by gravitational disturbance torques caused by uneven distribution of its own weight and load, resulting in deviations between its motion attitude and the actual on-orbit state. Therefore, effectively reducing or eliminating unbalanced torques and achieving a high degree of coincidence between the platform's center of mass and rotation center has become a key technical bottleneck in ensuring the accuracy of simulation experiments.

[0003] To ensure that an air-bearing platform can effectively simulate the microgravity environment of space, a key aspect is aligning the platform's center of mass with its center of rotation to reduce gravitational interference torque. Currently, most methods in this field employ a combination of manual coarse leveling and automatic fine leveling. Manual coarse leveling, as a preliminary step, typically involves operators relying on experience to repeatedly add, remove, and move counterweights, visually inspecting or using simple instruments to roughly restore the air-bearing platform to a horizontal position. Clearly, this leveling method, dependent on manual operation, has significant drawbacks, specifically in the following aspects:

[0004] 1. The leveling process is inefficient and time-consuming. Manual operation relies on experience and trial-and-error adjustments, which is cumbersome. A complete coarse leveling usually takes 2-3 hours, which seriously slows down the experimental preparation progress.

[0005] 2. Limited leveling accuracy restricts subsequent processes; manual leveling is difficult to guarantee accuracy and often only achieves a rough balance. This inaccurate initial state will put an extra burden on the subsequent automatic fine leveling system, significantly prolonging the time required for fine leveling, thus further increasing the total time of the entire leveling process.

[0006] 3. Poor adaptability and difficulty in coping with changing experimental requirements. During the service life of the air-bearing platform, in order to complete different simulation experimental tasks, it is necessary to frequently change the load on the platform. Each load change will cause the center of mass to shift, which requires re-leveling. The problem of low efficiency of manual coarse leveling is amplified in this scenario, making the experimental process lengthy and unable to meet the modern experimental requirements of rapid task switching.

[0007] In view of this, this application aims to provide a new technology for coarse leveling of the center of gravity of an air-floating platform that can achieve rapid, accurate and automated operation, in order to solve the above problems. Summary of the Invention

[0008] The purpose of this invention is to address at least one deficiency in the prior art by providing a system and method for rapid coarse adjustment and balancing of the center of mass of an air-bearing platform.

[0009] To achieve the above objectives, the technical solution provided by this invention is as follows: First, a system for rapid coarse adjustment and balancing of the center of mass of an air-bearing platform is provided, including a pressure measurement system, a control system, and an actuator; the pressure measurement system includes a base, a pressure sensor, and a positioning component; the pressure sensor is installed on the base to measure the pressure value at the corresponding position of the air-bearing platform and transmits the data to the control system; the positioning component provides a positioning reference for the air-bearing platform to ensure that the center of the air-bearing platform coincides with the center of the base; the control system is connected to the pressure measurement system and the actuator, and is used to receive the measured values ​​from the sensor and output corresponding control commands to the actuator after calculation; the actuator includes a motor, a clamp, a counterweight wire, and a shearing device; one end of the counterweight wire is fixed to the clamp, and the other end passes through the shearing device; the motor drives the clamp to rotate, thereby winding the counterweight wire around the clamp; the shearing device is configured to provide preload to the counterweight wire and cut the counterweight wire when receiving a control command from the control system.

[0010] Furthermore, the shearing device is equipped with a tension sensor to measure the tension borne by the counterweight wire and transmit it to the control system.

[0011] Furthermore, the base is rectangular and is composed of two symmetrical components joined together.

[0012] Furthermore, there are multiple pressure sensors, preferably four, distributed at the center points of the four sides of the base.

[0013] Furthermore, the motor and wire clamps are mounted on the air-floating platform, while the shearing device is mounted on the base.

[0014] Furthermore, the positioning component is a positioning pin, which is used to provide a reference surface for the air-bearing platform to ensure that the lever arms of multiple pressure sensors are the same from the center of the air-bearing platform.

[0015] Furthermore, the counterweight wire is a metal wire; preferably, the counterweight wire is a copper wire.

[0016] The present invention also provides a method for rapid coarse balancing of the center of mass of an air-bearing platform based on the above-mentioned device, comprising the following steps: S1, initial positioning:

[0017] Place the base under the air-float platform, and use the positioning component to make the center of the air-float platform coincide with the center of the base, so that the air-float platform is in a free state.

[0018] S2, threading:

[0019] The counterweight wire is passed through the shearing device and one end is fixed to the wire hoop. The shearing device provides tension to the counterweight wire and also provides guidance for the counterweight wire.

[0020] S3. Measurement and Calculation:

[0021] The pressure value at the corresponding point on the air-float platform is measured by a pressure sensor, and the tension value of the counterweight wire at the corresponding position is measured by a tension sensor on the shearing device. The measurement results are transmitted to the control system, which calculates the deviation of the center of mass of the air-float platform and simultaneously calculates the number of turns of the counterweight wire at the corresponding position.

[0022] S4. Adjust the center of gravity:

[0023] The control system controls the motor to operate based on the deviation of the center of gravity, so that the counterweight wire at the corresponding position is wound around the hoop to adjust the center of gravity;

[0024] S5. Confirm cut:

[0025] When the control system determines that the center of gravity has been adjusted to the set target range, it controls the shearing device to cut the counterweight wire and checks the leveling result through the pressure sensor.

[0026] Furthermore, in step S3, the control system calculates the target number of turns of the counterweight wire based on the following steps:

[0027] S31. Calculate the vertical tension on the counterweight wire:

[0028] Place the air-float platform under no-load conditions on the coarse adjustment balancing system, and record the reference pressure value at position x read by the pressure sensor as Fx0. Then place the load on the air-float platform, and record the pressure value at position x read by the pressure sensor as Fx′. The difference between Fx0 and Fx′ can be eliminated by the actuator to quickly realize the leveling work of the air-float platform under load conditions.

[0029] During the leveling process, the counterweight wire is subjected to a tensile force Fj applied to it by the shearing device; the horizontal component of the tensile force Fj can be denoted as Ft, and the vertical component as Fc; the horizontal component Ft will not affect the center of mass of the air-floating platform, but Fc will affect the center of mass of the air-floating platform. Therefore, it is necessary to calculate the variation law of the force Fc; Ft can be directly read by the tensile sensor in the shearing device. Let the distance between the fixed point of the counterweight wire (copper wire) on the wire hoop and the fixed point on the shearing device be L2 in the vertical direction and L1 in the horizontal direction, the diameter of the counterweight wire be d1, and the number of turns on the wire hoop be n. Then Fc can be calculated according to the following formula (1):

[0030] (1);

[0031] Where Ft is the horizontal component of the force, L1 is the horizontal distance between the two fixed points of the counterweight wire, L2 is the vertical distance between the two fixed points in the initial state, and d1 is the diameter of the counterweight wire.

[0032] S32. Calculate the weight of the counterweight wire:

[0033] Let the diameter at the winding position of the coil be d2 and the density of the copper wire be ρ. Then, the weight generated after the counterweight wire is wound around the coil n times is calculated according to the following formula (2):

[0034] G n =nπ 2 (d) 1+ d2) d1 2 ×ρ×g / 4 (2;

[0035] S33. Analyze the influence of the weight and tension of the counterweight wire on the pressure sensor reading:

[0036] Let the horizontal distance between the pressure sensor and the center of mass of the air-float platform be L, and the horizontal distance between the motor and the center of mass of the air-float platform be L. d According to the principle of torque, the vertical component F at position x is... cx and gravity G nx When converting to the pressure sensor position, it needs to be multiplied by a coefficient L. d / L; then the pressure value read from the pressure sensor when the coarse leveling system is working is:

[0037] F x = F x0 +(G nx +F cx L d / L (3);

[0038] S34. Calculate the number of laps n:

[0039] Assuming the center of mass of the air-bearing platform is adjusted to within a set value, the vertical component of the force at position x is F. cx ′ The corresponding measured horizontal component is F. t ′ When the counterweight wire is cut and the motor is stopped, the vertical component of the counterweight wire at position x will become zero. According to formula (3), we have:

[0040] F cx = 0;

[0041] F x = F max = F x0 + G nx L d / L; where F max The maximum values ​​read by the four pressure sensors when the air-float platform is first placed on the center of mass balancing device;

[0042] Therefore, to compensate for the loss of tension F in the vertical direction of the counterweight wire... cx ′ The subsequent effects require adjusting the tension F. cx ′ This is converted into the weight of the counterweight wire, that is, increasing the weight of the counterweight wire to G. ′ nx :

[0043] G ′ nx = G nx + F cx ′ =(F max -F x0 ) L / L d + F cx ′ (4);

[0044] The number of revolutions required to control the stepper motor through the control system can be calculated using formula (5):

[0045] (5);

[0046] The coarse leveling of the air-float platform can be completed after the motor rotates n revolutions.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] 1. In the solution of the present invention, the time for coarse leveling of the center of gravity of the air-bearing platform can be significantly reduced from 2 to 3 hours in the traditional manual method to 10 minutes through the coordinated work of the pressure measurement system, the control system and the actuator, which improves efficiency by more than an order of magnitude and greatly speeds up the experimental preparation process.

[0049] 2. The entire coarse leveling process of this invention, from pressure measurement and centroid offset calculation to the drive motor winding copper wire and finally cutting the copper wire, is automatically completed by the system, which completely changes the operation mode that relies on manual experience and repeated trial and error, and effectively eliminates the uncertainty and error introduced by human factors.

[0050] 3. In its non-operating state, the system of this invention can serve as a support mechanism to elevate the air-bearing platform, preventing continuous wear on the spherical air-bearing bearings and extending the equipment's service life. Simultaneously, its rapid response capability allows the air-bearing platform to quickly readjust when switching between different experimental loads, greatly improving its efficiency and adaptability in handling multi-task experiments. Attached Figure Description

[0051] Figure 1 is a three-dimensional schematic diagram of the system in an embodiment of the present invention;

[0052] Figure 2 is another perspective view of the system in an embodiment of the present invention;

[0053] Figure 3 is an enlarged view of part A in Figure 2;

[0054] Figure 4 is a three-dimensional view of the air-float platform;

[0055] Figure 5 is a side view of the air-floating platform;

[0056] Figure 6 is an exploded view of the base;

[0057] Figure 7 is a force analysis diagram of the counterweight wire in this invention;

[0058] In the diagram: 1. Base; 2. Air-float platform; 3. Motor; 4. Cable clamp; 5. Counterweight wire; 6. Shearing device; 7. Positioning pin; 8. Pressure sensor. Detailed Implementation

[0059] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0060] Example

[0061] As shown in Figures 1-6, this embodiment provides a rapid coarse adjustment balancing system for the center of mass of an air-bearing platform 2, which includes a pressure measurement system, a control system, and an actuator. The pressure measurement system includes a base 1, pressure sensors 8, and a positioning component. The pressure sensors 8 are mounted on the base 1 to measure the pressure value at the corresponding position of the air-bearing platform 2 and transmit the data to the control system. There are four pressure sensors 8, which are respectively located at the center of the four sides of the base 1. The positioning component is used to provide a positioning reference for the air-bearing platform 2. The positioning component is a positioning pin 7 to ensure that the center of the air-bearing platform 2 coincides with the center of the base 1. This ensures that the four pressure sensors 8 are at the same distance from the center of the air-bearing platform 2, that is, to ensure that the lever arms of the four pressure sensors 8 from the center of the air-bearing platform 2 are the same.

[0062] In this embodiment, the control system mainly consists of a computer and control software. The control system is communicatively connected to the pressure measurement system and the actuator. It is used to receive measurement data from relevant sensors, process the data, and output corresponding control commands to the actuator.

[0063] In this embodiment, the actuator includes a stepper motor 3, a wire clamp 4, a counterweight wire 5, and a shearing device 6. The counterweight wire 5 is made of copper wire, with one end fixed to the wire clamp 4 and the other end passing through the shearing device 6. The stepper motor 3 drives the wire clamp 4 to rotate, winding the counterweight wire 5 around the wire clamp 4 to adjust the center of gravity position of the air-float platform 2. The shearing device 6 is configured to provide preload to the counterweight wire 5 and cut the counterweight wire 5 upon receiving a control command from the control system. A tension sensor is mounted on the shearing device 6 to measure the horizontal tension value of the copper wire during the coarse leveling process and output it to the control system for calculation and analysis. It is also used to cut the copper wire after detecting that the center of gravity leveling of the air-float platform 2 is complete.

[0064] In this embodiment, the base 1 is a rectangular frame, the size of which matches the corresponding air-floating platform 2; and the base 1 is composed of two symmetrical components spliced ​​together. This facilitates quick assembly and disassembly during use. The stepper motor 3 and the wire clamp 4 are mounted on the air-floating platform 2, while the shearing device 6 is mounted on the base 1.

[0065] The method of using the device in this embodiment includes the following steps:

[0066] S1, Initial Positioning:

[0067] After assembling the two base components, place them under the air-bearing platform to support it. Then, tighten the air-bearing platform against the positioning pins on the base to ensure that the distance from the center of the air-bearing platform to the four pressure sensors is L. Then, remove the positioning pins to allow the air-bearing platform to be in a free state.

[0068] S2, threading:

[0069] The copper wire is passed through the shearing device and one end is fixed to the wire clamp. The shearing device provides tension and guidance to the copper wire.

[0070] S3. Measurement and Calculation:

[0071] The pressure value at the corresponding point on the air-float platform is measured by a pressure sensor, and the tension value of the counterweight wire at the corresponding position is measured by a tension sensor on the shearing device. All the measured values ​​are transmitted to the control system, which calculates the deviation of the air-float platform's center of gravity.

[0072] S4. Adjust the center of gravity:

[0073] The control system controls the motor to operate based on the deviation of the center of gravity, so that the counterweight wire at the corresponding position is wound around the hoop to adjust the center of gravity;

[0074] S5. Confirm cut:

[0075] When the control system determines that the center of gravity has been adjusted to the set target range, that is, the stepper motor has rotated the corresponding number of times, it controls the shearing device to cut the counterweight wire and checks the leveling result through the pressure sensor, thereby completing the entire leveling work.

[0076] Specifically, in step S3, the control system calculates the target number of turns of the counterweight wire based on the following steps:

[0077] S31. Calculate the vertical tension on the counterweight wire:

[0078] Place the air-float platform under no-load conditions on the coarse adjustment balancing system, and record the reference pressure value at position x read by the pressure sensor as Fx0. Then place the load on the air-float platform, and record the pressure value at position x read by the pressure sensor as Fx′. The difference between Fx0 and Fx′ can be eliminated by the actuator to quickly realize the leveling work of the air-float platform under load conditions.

[0079] During the leveling process, the counterweight wire is subjected to a tensile force Fj applied to it by the shearing device; the horizontal component of the tensile force Fj can be denoted as Ft, and the vertical component as Fc; the horizontal component Ft will not affect the center of mass of the air-floating platform, but Fc will affect the center of mass of the air-floating platform. Therefore, it is necessary to calculate the variation law of the force Fc; Ft can be directly read by the tensile sensor in the shearing device. Let the distance between the fixed point of the counterweight wire (copper wire) on the wire hoop and the fixed point on the shearing device be L2 in the vertical direction and L1 in the horizontal direction, the diameter of the counterweight wire be d1, and the number of turns on the wire hoop be n. Then Fc can be calculated according to the following formula (1):

[0080] (1);

[0081] Where Ft is the horizontal component of the force, L1 is the horizontal distance between the two fixed points of the counterweight wire, L2 is the vertical distance between the two fixed points in the initial state, and d1 is the diameter of the counterweight wire.

[0082] S32. Calculate the weight of the counterweight wire:

[0083] Let the diameter at the winding position of the coil be d2 and the density of the copper wire be ρ. Then, the weight generated after the counterweight wire is wound around the coil n times is calculated according to the following formula (2):

[0084] G n =nπ 2 (d) 1+ d2) d1 2 ρ g / 4 (2);

[0085] S33. Analyze the influence of the weight and tension of the counterweight wire on the pressure sensor reading:

[0086] Let the horizontal distance between the pressure sensor and the center of mass of the air-float platform be L, and the horizontal distance between the motor and the center of mass of the air-float platform be L. d According to the principle of torque, the vertical component F at position x is... cx and gravity G nx When converting to the pressure sensor position, it needs to be multiplied by a coefficient L. d / L; then the pressure value read from the pressure sensor when the coarse leveling system is working is:

[0087] F x = F x0 +(G nx +F cx L d / L (3);

[0088] S34. Calculate the number of laps n:

[0089] Assuming the center of mass of the air-bearing platform is adjusted to within a set value, the vertical component of the force at position x is F. cx ′ The corresponding measured horizontal component is F. t ′ When the counterweight wire is cut and the motor is stopped, the vertical component of the counterweight wire at position x will become zero. According to formula (3), we have:

[0090] F cx = 0;

[0091] F x = F max = F x0 + G nx L d / L; where F max The maximum values ​​read by the four pressure sensors when the air-float platform is first placed on the center of mass balancing device;

[0092] Therefore, in order to balance and compensate for the loss of tension F in the vertical direction of the counterweight wire... cx ′ The subsequent effects require adjusting the tension F. cx ′ This is converted into the weight of the counterweight wire, that is, increasing the weight of the counterweight wire to G. ′ nx :

[0093] G ′ nx = G nx + F cx ′ =(F max -F x0 ) L / L d + F cx ′ (4);

[0094] The number of revolutions of the stepper motor controlled by the control system needs to be calculated using the following formula (5):

[0095] (5).

[0096] The above are only some embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various combinations and modifications of the aforementioned technical features. Any improvements, modifications, equivalent substitutions, or applications of the structure or method of the present invention to other fields to achieve the same effect without departing from the spirit and scope of the present invention shall fall within the protection scope of the present invention.

Claims

1. A system for rapid coarse adjustment and balancing of the center of mass of an air-bearing platform, characterized in that: It includes a pressure measurement system, a control system, and an actuator; the pressure measurement system includes a base, a pressure sensor, and a positioning component; the pressure sensor is installed on the base to measure the pressure value at the corresponding position of the air-float platform and transmits the data to the control system; the positioning component is used to provide a positioning reference for the air-float platform to ensure that the center of the air-float platform coincides with the center of the base. The control system is connected to the pressure measurement system and the actuator. It receives the measured values ​​from the sensor and outputs corresponding control commands to the actuator after calculation. The actuator includes a motor, a coil, a counterweight wire, and a shearing device. One end of the counterweight wire is fixed to the coil, and the other end passes through the shearing device. The motor drives the coil to rotate, thereby winding the counterweight wire around the coil. The shearing device is configured to provide preload to the counterweight wire and cut the counterweight wire when it receives a control command from the control system.

2. The system for rapid coarse adjustment and balancing of the center of mass of an air-floating platform according to claim 1, characterized in that: The shearing device is equipped with a tension sensor to measure the tension borne by the counterweight wire and transmit it to the control system.

3. The system for rapid coarse adjustment and balancing of the center of mass of an air-floating platform according to claim 2, characterized in that: The base is rectangular and is composed of two symmetrical components joined together.

4. The system for rapid coarse adjustment and balancing of the center of mass of an air-floating platform according to claim 3, characterized in that: There are four pressure sensors, which are respectively installed at the center points of the four sides of the base.

5. The system for rapid coarse adjustment and balancing of the center of mass of an air-floating platform according to claim 2, characterized in that: The motor and wire clamp are mounted on the air-floating platform, while the shearing device is mounted on the base.

6. The system for rapid coarse balancing of the center of mass of an air-floating platform according to claim 2, characterized in that: The positioning component is a positioning pin, which is used to provide a reference surface for the air-float platform to ensure that the lever arms of multiple pressure sensors are the same from the center of the air-float platform.

7. The system for rapid coarse adjustment and balancing of the center of mass of an air-floating platform according to claim 2, characterized in that: The counterweight wire is a metal wire.

8. A method for rapid coarse balancing of the center of mass of an air-bearing platform, employing the system described in any one of claims 2-7, characterized in that, Includes the following steps: S1. Initial Positioning: Place the base under the air-float platform. Use positioning components to align the center of the air-float platform with the center of the base, allowing the air-float platform to be in a free state. S2. Threading: Thread the counterweight wire through the shearing device and fix one end to the wire clamp. The shearing device provides tension to the counterweight wire and also provides guidance. S3. Measurement and Calculation: Measure the pressure value at the corresponding point on the air-float platform using a pressure sensor. Measure the tension value of the counterweight wire at the corresponding position using a tension sensor on the shearing device. Transmit the measured values ​​to the control system, which calculates the deviation of the air-float platform's center of gravity and simultaneously determines the number of turns of the counterweight wire at the corresponding position. S4. Adjusting the center of gravity: The control system controls the motor to run according to the deviation of the center of gravity, so that the counterweight wire at the corresponding position is wound on the hoop to adjust the center of gravity; S5. Shearing confirmation: When the control system determines that the center of gravity has been adjusted to the set target range, it controls the shearing device to cut the counterweight wire, and the leveling result is checked by the pressure sensor.

9. The method for rapid coarse adjustment and balancing of the center of mass of an air-floating platform according to claim 8, characterized in that, In step S3, the control system calculates the target number of turns n of the counterweight wire based on the following steps: S31, Calculate the vertical tension on the counterweight wire: Place the air-floating platform in an unloaded state on the coarse adjustment balancing system, and record the reference pressure value at the position read by the pressure sensor as F. x0 Then the load is placed on the air-float platform. At this time, the pressure value at position x is read by the pressure sensor and recorded as Fx′. The difference between Fx0 and Fx′ can be eliminated by the actuator to quickly realize the leveling work of the air-float platform under load. During the leveling process, the counterweight wire is subjected to the tension Fj applied by the shearing device. The horizontal component of the tension Fj is recorded as Ft, and the vertical component is recorded as Fc. The horizontal component Ft does not affect the center of mass of the air-float platform, but Fc will affect the center of mass of the air-float platform. It is necessary to calculate the change law of the force Fc. Ft is directly read by the tension sensor in the shearing device. The distance between the fixed point of the copper wire on the wire hoop and the fixed point on the shearing device is recorded as L2 in the vertical direction and L1 in the horizontal direction. The diameter of the counterweight wire is d1, and the number of turns on the wire hoop is n. Then Fc is calculated according to the formula (1) below: (1); where Ft is the horizontal component, L1 is the horizontal distance between the two fixed points of the counterweight wire, L2 is the vertical distance between the two fixed points in the initial state, and d1 is the diameter of the counterweight wire; S32, calculate the weight of the counterweight wire: let the diameter at the winding position of the wire hoop be d2 and the density of the copper wire be ρ, then the weight generated after the counterweight wire is wound around the wire hoop n times is calculated according to the following formula (2): G n =nπ 2 (d) 1+ d2) d1 2 ×ρ×g / 4 (2;S33、Analyze the influence of the weight and tension of the counterweight wire on the pressure sensor reading: Let the horizontal distance between the pressure sensor and the center of mass of the air-floating platform be L, and the horizontal distance between the motor and the center of mass of the air-floating platform be L d The vertical component F at position x cx and gravity G nx When converting to the pressure sensor position, it needs to be multiplied by a coefficient L. d / L; then the pressure value read from the pressure sensor when the coarse leveling system is working is: F x = F x0 +(G nx +F cx L d / L (3); S34, Calculate the number of revolutions n: Assume that when the center of mass of the air-floating platform is adjusted to within the set value, the vertical component of the force at position x is F. cx ′ The corresponding measured horizontal component is F. t ′ When the counterweight wire is cut and the motor is stopped, the vertical component of the counterweight wire at position x will become zero. According to formula (3), we have: F cx = 0; F x = F max = F x0 + G nx L d / L; where F max The values ​​read by the four pressure sensors when the air-float platform is initially placed on the center of gravity balancing device; to compensate for the loss of tension F in the vertical direction of the counterweight wire. cx ′ The effect requires the tension F to be... cx ′ Convert this to the weight of the counterweight wire, and denote the final weight of the counterweight wire as G. ′ nx Then: G ′ nx = G nx + F cx ′ =(F max -F x0 ) L / L d + F cx ′ (4); The number of revolutions of the stepper motor controlled by the control system is calculated according to formula (5): （5）。

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