Mass center measuring device based on spherical air bearing

Abstract

The invention discloses a mass center measuring device based on a spherical air bearing, and belongs to the field of mass characteristic parameter metering and measuring. The device comprises a working table, a spherical air bearing, a rotating shaft, a cylindrical air bearing, a knife edge supporting mechanism, a force sensor and a table body. A rotating shaft is mounted on the lower surface of the spherical air bearing, and the axis of the rotating shaft passes through the sphere center of the spherical air bearing and the center of the workbench; the cylindrical surface air bearing sleeves the bottom of the rotating shaft, and the side surface is connected with the force sensor through the knife edge supporting mechanism; the force sensors are mounted on the table body and are uniformly distributed around the cylindrical surface air bearing at 90-degree intervals; an air film is formed between an air floating ball and a ball bowl of the spherical air floating bearing, an air film is formed between the inner surface of the cylindrical air floating bearing and the rotating shaft, and an air film is formed between the bottom surface and the table body; a measured object is installed on the workbench, torque formed by mass center deviation of the measured object is transmitted to the force sensor through the mechanical system, and the mass center position of the measured object is measured according to the torque balance principle.

Description

Technical Field

[0001] This invention relates to a centroid measuring device based on a spherical air bearing, belonging to the field of mass characteristic parameter measurement technology. Background Technology

[0002] Mass characteristic parameters are inherent properties of an object, mainly including mass, center of mass, and moment of inertia. The center of mass is a parameter used for motion control of an object and has wide applications in the aerospace field.

[0003] Currently, centroid measurement is generally achieved using multi-point weighing equipment. However, this type of equipment has the following problems: First, the measurement accuracy is not high enough; second, the centering effect is poor, as the measurement center of multi-point weighing equipment cannot be accurately determined; and third, the measurement point is limited, as multi-point weighing equipment can generally only measure the centroid at the current installation state. Summary of the Invention

[0004] To address the problems of insufficient measurement accuracy, poor centering effect, and limited measurement points in existing centroid measurement equipment, the present invention aims to provide a centroid measurement device based on a spherical air bearing. This device utilizes the excellent centering effect of the spherical air bearing, enabling full rotation and measurement at any point, thereby improving the accuracy of centroid measurement.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] The present invention discloses a centroid measuring device based on a spherical air bearing, comprising a worktable, an air-bearing ball, a ball cup, a rotating shaft, a circular grating, a reading head, a cylindrical air bearing, a knife-edge support mechanism, a force sensor, a platform, and a linear guide rail.

[0007] The worktable surface has threaded holes and locating pin holes for mounting the object being measured. The spherical air bearing consists of an air float and a cup; air film is formed between the air float and the cup by supplying air, and the cup is fixedly connected to the worktable. The cylindrical air bearing consists of a rotating shaft and an air sleeve; air film is formed between the rotating shaft and the air sleeve by supplying air. The worktable is mounted on the upper surface of the air float, and the rotating shaft is mounted on the lower surface. The circular grating is mounted on the rotating shaft, and the reading head is mounted on the air sleeve. The air sleeve is connected to the force sensor via a knife-edge support mechanism. The force sensor is connected to the stage body via a linear guide mechanism.

[0008] The blade support mechanism consists of a blade bearing, a blade, and a blade mounting base. The blade bearing is installed on the outer surface of the air bearing sleeve, the blade mounting base is fixedly connected to the force sensor, and the blade is installed on the blade mounting base by means of a cylindrical pin connection.

[0009] The air float, worktable, and rotary shaft are connected by screws. The axis of the rotary shaft passes through the center of the air float and the center of the worktable, and can rotate around the rotary center when air is supplied.

[0010] The force sensor is fixedly connected to the linear guide rail by a force sensor mounting base via threads. The through hole at the connection between the force sensor mounting base and the sensor is in the shape of a long slot, providing a certain adjustment margin.

[0011] There are 4 sets of knife-edge support mechanisms, evenly distributed around the air-bearing bushing at 90° intervals. There are also 4 sets of corresponding sensors, force sensor mounting bases and linear guides. The force sensors can be electromagnetic force sensors or strain gauge force sensors.

[0012] Both the cutting edge and the tool bearing are installed horizontally, and the four tool bearings are installed on the same horizontal plane. The cutting edge connected to the sensor is adjusted up and down to ensure that it is at the same height as the tool bearing.

[0013] Two sets of knife edge support mechanisms spaced 180° apart constitute a pair. The same pair of knife edges are adjusted to contact the knife bearing via a linear guide rail. The linear guide rail is continuously adjusted to ensure that the force sensor connected to the pair of knife edges has a preload of 1 / 3 of its range before locking. The other pair of knife edges is adjusted in the same way.

[0014] The torque generated by the displacement of the center of mass of the object being measured is gradually transmitted to the force sensor through the mechanical system, and the position of the center of mass of the object being measured is realized according to the principle of torque balance.

[0015] Beneficial effects:

[0016] 1. The present invention discloses a centroid measuring device based on a spherical air bearing. By utilizing the good centering effect of the spherical air bearing, the origin of the device's coordinate system can be accurately positioned at the center of the spherical air bearing, which facilitates the determination of the initial coordinate system during the centroid measurement process.

[0017] 2. The present invention discloses a centroid measuring device based on a spherical air bearing, which adopts a support method in which the blade and the bearing are horizontally installed, and the contact position of the force is in the same horizontal plane, which facilitates the accurate acquisition of the lever arm length when calculating the centroid.

[0018] 3. The present invention discloses a centroid measuring device based on a spherical air bearing, which uses four sets of knife-edge support mechanisms and four corresponding sets of sensors evenly distributed around the perimeter at 90° intervals, with two sets forming a pair. It can output sensor measurement results in two directions, which is convenient for directly measuring the centroid position in two directions in the spatial coordinate system. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a centroid measuring device based on a spherical air bearing according to the present invention.

[0020] Figure 2 This is a schematic diagram of the knife-edge support mechanism and sensor assembly in this invention;

[0021] Figure 3 This is a schematic diagram of the sensor location distribution;

[0022] Among them, 1—worktable, 2—air float, 3—ball cup, 4—rotary shaft, 5—circular grating, 6—reading head, 7—cylindrical air float bearing, 8—knife edge support mechanism, 9—force sensor, 10—platform body, 11—knife bearing, 12—knife edge, 13—knife edge mounting base, 14—force sensor mounting base, 15—linear guide rail. Detailed Implementation

[0023] To better illustrate the purpose and advantages of the present invention, the invention will be further described below in conjunction with the accompanying drawings and examples.

[0024] Example 1:

[0025] This embodiment discloses a centroid measuring device based on a spherical air bearing, including a worktable 1, an air-bearing ball 2, a ball cup 3, a rotating shaft 4, a circular grating 5, a reading head 6, a cylindrical air bearing 7, a knife-edge support mechanism 8, a force sensor 9, a platform 10, a knife bearing 11, a knife edge 12, a knife-edge mounting base 13, a force sensor mounting base 14, and a linear guide rail 15.

[0026] like Figure 1 As shown, the upper surface of the worktable 1 has threaded holes and locating pin holes for mounting the object being measured. The spherical air bearing consists of an air float 2 and a ball cup 3. An air film is formed between the air float 2 and the ball cup 3 by supplying air, and the ball cup 3 is fixedly connected to the worktable 1. The cylindrical air bearing 6 consists of a rotating shaft 4 and an air bearing sleeve. An air film is formed between the rotating shaft 4 and the air bearing sleeve by supplying air. The worktable 1 is mounted on the upper surface of the air float 2, and the rotating shaft 4 is mounted on the lower surface. The circular grating 5 is mounted on the rotating shaft, and the reading head 6 is mounted on the air bearing sleeve. The air bearing sleeve is connected to the force sensor 9 via a knife-edge support mechanism 8. The force sensor 9 is connected to the platform 10 via a linear guide mechanism 15.

[0027] like Figure 2 As shown, the blade support mechanism 8 consists of a blade bearing 11, a blade 12, and a blade mounting base 13. The blade bearing 11 is installed on the outer surface of the air flotation sleeve, the blade mounting base 13 is fixedly connected to the force sensor 9, and the blade 12 is installed on the blade mounting base 13 by means of a cylindrical pin connection.

[0028] The air float 2, the worktable 1, and the rotary shaft 4 are connected by screws. The axis of the rotary shaft 4 passes through the center of the air float 2 and the center of the worktable 1, and can rotate around the center of rotation when air is supplied.

[0029] Force sensor 9 is fixedly connected to linear guide rail 15 by force sensor mounting base 14 through thread. The through hole at the connection between force sensor mounting base 14 and force sensor 9 is in the shape of an elongated groove, which has a certain adjustment margin.

[0030] like Figure 3 As shown, there are 4 sets of knife-edge support mechanisms 8, which are evenly distributed around the air-bearing bushing at 90° intervals. There are also 4 sets of corresponding force sensors 9, force sensor mounting bases 14 and linear guides. The force sensors 9 can be electromagnetic force sensors or strain gauge force sensors.

[0031] Both the cutting edge 12 and the blade bearing 11 are installed horizontally. The four blade bearings 11 are installed on the same horizontal plane. The cutting edge 12 connected to the force sensor 9 is adjusted up and down to ensure that it is at the same height as the blade bearing 11.

[0032] Two sets of blade support mechanisms 8 spaced 180° apart are a pair. The blades 12 of the same pair are adjusted to contact the blade bearings 11 through the linear guide rail 15. The linear guide rail 15 is continuously adjusted to ensure that the force sensor 9 connected to the pair of blades 12 has a preload of 1 / 3 of its range and is then locked. The other pair is adjusted in the same way.

[0033] The working method of the centroid measuring device based on a spherical air bearing disclosed in this embodiment is as follows:

[0034] Step 1: Power on the device and check that it is working properly. Zero the force sensor 9 and install the object to be measured at a suitable position on the worktable 1 of the centroid measuring device so that the coordinate system of the object to be measured coincides with the coordinate system of the device. According to the output of the angle measuring mechanism, rotate the worktable to the 0° position and record the output results of the four sensors F1, F2, F3, and F4 at this time. Calculate the current centroid position according to formulas (1) and (2) and record it as (x1, y1).

[0035]

[0036] In the formula, m is the mass of the measured item, x is the centroid of the measured item in the X-axis direction, and y is the centroid of the measured item in the Y-axis direction.

[0037] Step 2: Based on the output of the angle measuring mechanism, rotate the worktable to 90°, 180° and 270° respectively, record the output of the force sensor at each position, and calculate the position of the center of mass according to formula (1) and (2), and record it as (x2,y2), (x3,y3) and (x4,y4).

[0038] Step 3: Average the measured centroid records according to formulas (3) and (4) to obtain the final centroid measurement result of the measured item as (x0, y0). The measurement is then completed, and the measured item is removed.

[0039]

[0040] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A centroid measuring device based on a spherical air bearing, characterized in that: It includes a worktable, air-bearing ball, ball cup, rotary shaft, circular grating, reading head, cylindrical air-bearing bearing, knife-edge support mechanism, force sensor, platform body and linear guide rail; The worktable surface is provided with threaded holes and positioning pin holes for mounting the object to be measured; the spherical air bearing consists of an air float and a ball cup, and an air film is formed between the air float and the ball cup by air supply, with the ball cup fixedly connected to the worktable; the cylindrical air bearing consists of a rotary shaft and an air bearing sleeve, and an air film is formed between the rotary shaft and the air bearing sleeve by air supply; the worktable is mounted on the upper surface of the air float, and the rotary shaft is mounted on the lower surface; the circular grating is mounted on the rotary shaft, and the reading head is mounted on the air bearing sleeve; the air bearing sleeve is connected to the force sensor through a knife-edge support mechanism; the force sensor is connected to the stage body through a linear guide mechanism.

2. The apparatus as described in claim 1, characterized in that: The blade support mechanism consists of a blade bearing, a blade, and a blade mounting base. The blade bearing is installed on the outer surface of the air bearing sleeve, the blade mounting base is fixedly connected to the force sensor, and the blade is installed on the blade mounting base by means of a cylindrical pin connection.

3. The apparatus as described in claim 1, characterized in that: The air float, worktable, and rotary shaft are connected by screws. The axis of the rotary shaft passes through the center of the air float and the center of the worktable, and can rotate around the rotary center when air is supplied.

4. The apparatus as described in claim 1, characterized in that: The force sensor is fixedly connected to the linear guide rail by a force sensor mounting base via threads. The through hole at the connection between the force sensor mounting base and the sensor is in the shape of a long slot, and the force sensor has an adjustment margin in the vertical installation position.

5. The apparatus as described in claim 2, characterized in that: There are 4 sets of knife-edge support mechanisms, evenly distributed around the air-bearing bushing at 90° intervals. There are also 4 sets of corresponding sensors, force sensor mounting bases and linear guides. The force sensors are either electromagnetic force sensors or strain gauge force sensors.

6. The apparatus as described in claim 2, characterized in that: Both the cutting edge and the tool bearing are installed horizontally, and the four tool bearings are installed on the same horizontal plane. The cutting edge connected to the sensor is adjusted up and down to ensure that it is at the same height as the tool bearing.

7. The apparatus as described in claim 6, characterized in that: Two sets of knife edge support mechanisms spaced 180° apart constitute a pair. The same pair of knife edges are adjusted to contact the knife bearing via a linear guide rail. The linear guide rail is continuously adjusted to ensure that the force sensor connected to the pair of knife edges has a preload of 1 / 3 of its range before locking. The other pair of knife edges is adjusted in the same way.

8. The apparatus as described in claim 1, 2, 3, 4, 5, 6 or 7, characterized in that: The object to be measured is mounted on the worktable. The torque generated by the displacement of the object's center of mass is gradually transmitted to the force sensor through the mechanical system. The position of the object's center of mass is measured based on the principle of torque balance.

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