Method for forcibly centering base

Abstract

The invention relates to a method for forcibly centering a base, belongs to the technical field of engineering measurement, and solves the problems of large measurement error in the vertical direction, low working efficiency and lack of theoretical models after repeated adjustment of a traditional base. Through cooperative constraint of double universal joints and linkage adjustment of three foot screws, a mathematical model is combined for driving calibration, the universal joints at the bottom of a base lock a three-dimensional datum point, the universal joints in the middle of the base and the foot screws cooperatively adjust the posture of a centering rod, and a unique horizontal plane and a unique vertical line are established; parameters are quantified and adjusted based on a displacement-angle relation formula and a plane equation, and a level or an electronic inclinometer is used for judging a calibration state, so that the position of the top equipment of the centering rod is uniquely determined by an intersection point of a vertical line and a plane. According to the invention, the perpendicularity error is lt; the method has the advantages that the horizontal direction and the vertical direction can be synchronously calibrated through one-time leveling, the efficiency is improved by more than 50%, the structure robustness, the long-term stability and the environmental adaptability are achieved, the method is suitable for total station three-dimensional monitoring, GNSS antenna installation and industrial precision measurement, and the measurement precision and reliability are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and particularly to a method for a forced centering base. Background Art

[0002] In the fields of engineering surveying and precision monitoring, traditional forced centering bases mostly rely on manual adjustment of the leveling screws for leveling. However, due to structural limitations, the centering rod is prone to millimeter-level displacement errors in the vertical direction, resulting in insufficient reliability of three-dimensional deformation monitoring data. Existing technologies generally have problems such as low adjustment efficiency and uncontrollable vertical errors, and lack a theoretical model to quantify the calibration process. Relying on empirical operations is likely to introduce residual deviations and it is difficult to meet the requirements of high-precision scenarios.

[0003] Traditional bases usually adjust the level through the leveling screws and rely on the centering rod to only achieve horizontal positioning. However, the existing technologies have the following significant defects: 1. Ordinary bases can only adjust the horizontal direction through the leveling screws, but due to structural limitations, the centering rod will have a large displacement error (up to 1 centimeter) in the vertical direction, resulting in unreliable three-dimensional deformation monitoring data; 2. Existing bases need to repeatedly adjust the level and centering multiple times, with complex operations and it is difficult to adapt to the requirements of rapid field monitoring; 3. Traditional technologies rely on empirical adjustments and do not establish geometric constraints or kinematic models, resulting in limited improvement in accuracy and difficulty in quantitative verification. Summary of the Invention

[0004] In view of the technical problems existing in the background art, the present invention provides a method for a forced centering base. By locking a three-dimensional reference point through a bottom universal joint, combining the cooperation of a middle universal joint and three leveling screws in the base, constructing a unique horizontal plane and a vertical line, and introducing a geometric model to accurately describe the relationship between displacement and angle, it realizes synchronous calibration of the horizontal and vertical directions with a single leveling, optimizes the vertical error to the sub-millimeter level, significantly improves the measurement efficiency and accuracy, and provides a reliable solution for three-dimensional monitoring in complex environments.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions to achieve: A method for a forced centering base, which determines a fixed point outside the plane through a first universal joint at the bottom, combines the coordinated adjustment of a second universal joint in the middle of the base and three leveling screws, so that when the spirit level bubble installed on the centering rod is centered, a unique horizontal plane is formed, and a unique vertical line between this plane and the center point at the bottom of the base is determined, realizing forced centering in three-dimensional space. The method specifically includes the following steps: a). Fix the bottom of the base on the measuring point observation pier through the first universal joint, ensuring that the bottom center point is located at the origin of the three-dimensional coordinate system; b), by using the linkage adjustment of the second universal joint and the three foot screws, the centering rod is displaced in the horizontal and vertical directions; c), determine the establishment of the horizontal plane by centering the spirit bubble, and determine the unique vertical line between the plane and the bottom center point based on geometric constraints; d), the position of the prism or satellite antenna at the top of the centering rod is uniquely determined by the intersection point of the vertical line and the horizontal plane.

[0006] In the preferred solution, the first universal joint is a ball joint structure, and its center point coincides with the center of the base bottom, which is used to restrict the degrees of freedom of the base outside the plane and ensure the fixed position of the bottom center point.

[0007] In the preferred solution, the second universal joint is composed of a bushing, a universal ball and a bracket. The universal ball is rigidly connected to the centering rod. By adjusting the height of the three foot screws, the universal ball is driven to move in the bushing, so that the centering rod generates displacements in the horizontal and vertical directions.

[0008] In the preferred solution, the adjustment of the three foot screws satisfies the following mathematical model: ; where, is the displacement in the vertical direction, , are the horizontal and pitch angle offsets respectively, is the transmission coefficient of the universal joint.

[0009] In the preferred solution, the uniqueness of the horizontal plane is determined by the following geometric relationship: ; where, the coefficients of the plane equation are uniquely calculated through the adjustment amounts of the three foot screws and the movement trajectory of the universal joint, and satisfy the constraint condition of the spirit bubble being centered.

[0010] In the preferred solution, the vertical state of the centering rod is indirectly determined by the centering of the spirit bubble, and its verticality error is less than 0.1 mm / m.

[0011] In the preferred solution, the three-dimensional coordinates of the prism or satellite antenna installed at the top of the centering rod are determined by the following formula: ; where, is the coordinate of the bottom center point, is the length of the centering rod, , , is the centering rod.

[0012] In a preferred embodiment, the adjustment accuracy of the foot screw is 0.01 mm / turn, and the three foot screws are symmetrically distributed at 120°, forming an equilateral triangle support structure.

[0013] In a preferred embodiment, the spirit level bubble is a double-axis long spirit level or a high-precision electronic inclinometer, and its resolution is not less than 2 arc seconds.

[0014] In a preferred embodiment, the method is applicable to the fields of total station three-dimensional deformation monitoring, GNSS antenna directional installation, and industrial precision measurement, and can achieve synchronous calibration in the horizontal and vertical directions through a single leveling.

[0015] This patent can achieve the following beneficial effects: 1. Through the collaborative constraint of the double universal joints and the geometric model drive, the present invention eliminates the vertical direction error caused by mechanical clearance, and optimizes the perpendicularity deviation to the sub-millimeter level (<0.1 mm / m), significantly improving the reliability of the three-dimensional deformation monitoring data; 2. Combining the linkage adjustment of the three foot screws and the determination of the spirit level bubble being centered, synchronous calibration in the horizontal and vertical directions is achieved, and the operation steps are simplified by more than 50%, especially suitable for field rapid monitoring sites; 3. Introducing mathematical models (such as plane equations, displacement-angle relationship formulas) to accurately describe the adjustment process, avoiding residual errors caused by empirical operations, and the calibration accuracy can be verified through parametric indicators; 4. The double universal joint design effectively decouples the degrees of freedom in the horizontal and vertical directions, reducing the coupling error; it is compatible with various observation devices such as prisms and GNSS antennas, meeting the diverse needs of total stations, satellite navigation systems, and industrial precision measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following further describes the present invention in conjunction with the drawings and embodiments: Figure 1 It is a flow chart of the method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] Embodiment 1: Implementation of the basic structure This Embodiment 1 provides a specific structure and operation process of a forced centering base: S1. Structural configuration: S1.1. The first universal joint at the bottom of the base is a ball joint structure, and its center point coincides with the geometric center of the lower base plate of the base. It is fixed to the forced centering axis of the observation pier through bolts to constrain the displacement of the base outside the horizontal plane; S1.2. The second universal joint in the middle of the base consists of a universal ball (diameter 20 mm), a bushing, and a bracket. The universal ball is tightly fitted with the inner wall of the bushing through a hot sleeve process. The centering rod (length 1.2 m) passes through the center of the universal ball and is rigidly connected to the universal ball; S1.3. The three precision foot screws (pitch 0.5 mm / rev) are symmetrically distributed at 120° and installed on the edge of the upper base, connected to the lower base by threads, with an adjustment precision of 0.01 mm / rev. S1.4. The upper base and the lower base are limited by a V-shaped guide rail to ensure that only vertical displacement occurs at the base when the foot screws are adjusted. S1.5. A dual-axis long-level bubble (resolution 2 arc seconds) is installed in the middle of the centering rod, and a standard interface (such as 5 / 8-inch thread) is provided at the top for installing a prism or a GNSS antenna. S2. Operation process and mathematical model: S2.1. Fix the base to the observation pier through the bottom universal joint to ensure that the center point coordinates of the base are ; S2.2. Adjust the three foot screws to drive the upper base to produce vertical displacement. ; where 、 is the inclination angle of the centering rod (measured by the offset of the level bubble), is the transmission coefficient of the universal joint; S2.3. When the level bubble is centered (inclination angle ), the centering rod is in the plumb state, and the three-dimensional coordinates of the prism at its top are: ; where L = 1.2 m is the length of the centering rod, and the vertical direction error is less than 0.05 mm; S3. Effect verification: In the slope monitoring scenario, the single leveling time is shortened from 10 minutes of the traditional base to 3 minutes, and the vertical direction repeatability error is ±0.08 mm, meeting the sub-millimeter level monitoring requirements.

[0018] Example 2: High-precision industrial measurement adaptation scheme; In this Example 2, the structure is optimized for the complex industrial site environment (such as vibration and temperature difference); S1. Structure improvement: S1.1. The base is made of invar alloy (thermal expansion coefficient 1.2*10 , , , , , , ,

[0018] , , , , , , , , , -6 , , , , , , , / °C), and the universal joint bushing is embedded with a polyurethane damping layer (damping ratio 0.3) to reduce environmental vibration interference; S1.2. Replace the mechanical level bubble with a dual-axis electronic inclinometer (resolution 0.5 arc seconds), and the data is transmitted to the controller in real time to automatically calculate the adjustment amount of the foot screws; S1.3. Use electric foot screws (driven by a stepper motor, single-step displacement 0.005 mm), supporting remote control and programmatic adjustment; S2. Calibration process and model optimization: S2.1. After the base is installed, the electronic inclinometer monitors the tilt angle of the centering rod in real time , The controller is based on the preset plane equation; ; Calculate the target displacement of the foot screw , and automatically adjust it through the motor; S2.2. When the inclinometer outputs , it is determined that the calibration is completed, and the system locks the position of the foot screw; S3. Application effect: In the installation scenario of a numerically controlled machine tool (ambient vibration frequency 5 - 50 Hz), after calibration, the positioning error at the top of the centering rod is ±0.03 mm, and the drift amount is less than 0.01 mm / 8 h under temperature fluctuations (±10 °C), which is significantly better than the ±0.5 mm error of the traditional base.

[0019] The above embodiments are only the preferred technical solutions of the present invention and should not be regarded as limitations on the present invention. The protection scope of the present invention should be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, the equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A forced centering base method, characterized in that: Determine a fixed point outside the plane through the first universal joint at the bottom of the base. Combine the coordinated adjustment of the second universal joint in the middle of the base and the three foot screws, so that when the spirit bubble installed on the centering rod is centered, a unique horizontal plane is formed, and a unique vertical line between this plane and the center point at the bottom of the base is determined, realizing forced centering in three-dimensional space. The method specifically includes the following steps: a), Fix the bottom of the base on the measuring point observation pier through the first universal joint to ensure that the center point at the bottom is located at the origin of the three-dimensional coordinate system; b), Use the linkage adjustment of the second universal joint and the three foot screws to displace the centering rod in the horizontal and vertical directions; c), Determine the establishment of the horizontal plane by the centering of the spirit bubble, and determine the unique vertical line between this plane and the center point at the bottom through geometric constraints; d), The position of the prism or satellite antenna at the top of the centering rod is uniquely determined by the intersection point of the vertical line and the horizontal plane.

2. The forced centering base method according to claim 1, characterized in that: The first universal joint is a ball joint structure, and its center point coincides with the center point at the bottom of the base, which is used to restrict the degrees of freedom of the base outside the plane and ensure the fixed position of the center point at the bottom.

3. The forced centering base method according to claim 1 or 2, characterized in that: The second universal joint is composed of a bushing, a universal ball and a bracket. The universal ball is connected to the centering rod. By adjusting the heights of the three foot screws, the universal ball is driven to move in the bushing, causing the centering rod to displace in the horizontal and vertical directions.

4. The forced centering base method according to claim 3, characterized in that: The adjustment of the three foot screws satisfies the following mathematical model: ； Among them, is the vertical displacement, , are the horizontal and pitch angle offsets respectively, is the universal joint transmission coefficient.

5. The forced centering base method according to claim 1, characterized in that: The uniqueness of the horizontal plane is determined by the following geometric relationship: ； Among them, the coefficients of the plane equation are uniquely calculated through the adjustment amounts of the three foot screws and the movement trajectories of the universal joints, and satisfy the constraint condition of the centering of the spirit bubble.

6. The forced centering base method according to claim 1, wherein: The vertical state of the centering rod is indirectly determined by the centering of the spirit bubble, and its verticality error is less than 0.1 mm / m.

7. The forced centering base method according to claim 1, characterized in that: The three-dimensional coordinates of the prism or satellite antenna installed at the top of the centering rod are determined by the following formula: ； Among them, is the coordinate of the bottom center point, is the length of the centering rod, , , are the centering rods.

8. The forced centering base method according to claim 1, characterized in that: The adjustment accuracy of the foot screws is 0.01 mm / turn, and the three foot screws are symmetrically distributed at 120° around the center of the base, forming an equilateral triangle support structure.

9. The forced centering base method according to claim 1, wherein: The spirit bubble is a two-axis long bubble level or a high-precision electronic inclinometer, and its resolution is not less than 2″.

10. The forced centering base method according to claim 1, characterized in that: The method is applicable to the fields of three-dimensional deformation monitoring of total stations, GNSS antenna directional installation and industrial precision measurement, and can realize synchronous calibration in the horizontal and vertical directions through a single leveling.

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