Special absolute displacement measuring device for vibration table and method for expanding vibration absorbing frequency band of vibration absorber

Abstract

The application discloses a kind of absolute displacement measuring devices special for vibration table, including the base for fixing the device, the main part for eliminating vibration and the clamping device for installing sensor;The base part is connected with support through disc spring;The clamping device of upper part of support is connected with the main part by upper and lower two pressing plates and screw;Support inside has mass block, and is connected with holding device by spring;The upper surface of base is provided with sensor;Electromagnet support is fixed in the middle part of base by thread;Electromagnet support bottom has wire slot, and upper part is provided with electromagnet;Signal collected by sensor is transmitted to electromagnet after being processed by processing system.

Description

Technical Field

[0001] This invention belongs to the technical field of dynamic vibration absorbers, specifically relating to a special absolute displacement measuring device for vibration tables and a method for expanding the vibration absorption frequency band of vibration absorbers. Background Technology

[0002] Currently, studying the dynamic parameters of machine tools using vibration tables often requires measuring the vibration amplitude of the machine tool tip, spindle, and other machine tool structures. Existing sensors are usually fixed to the vibration table or the ground. Sensors fixed to the vibration table will vibrate with the vibration of the table, while sensors fixed to the ground will also vibrate due to the environmental influence of the vibration table, affecting the measurement accuracy of the sensors. Summary of the Invention

[0003] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a vibration table-specific absolute displacement measuring device and a method for expanding the vibration absorption bandwidth of a vibration absorber, which eliminates sensor vibrations caused by vibrations at various frequencies. This is achieved by applying an external load to a mass block.

[0004] The technical solution of the present invention: The present invention provides a vibration table-specific absolute displacement measuring device, comprising a base portion, a main body portion disposed on the base portion, an acceleration sensor, and a processing system for processing the acceleration sensor signal; the top of the main body portion is provided with a sensor assembly for measuring displacement, and the base portion and the main body portion are connected by a disc spring;

[0005] A compression spring is provided within the main body along its length; one end of the compression spring is connected to the upper end of the main body, and the other end is connected to a mass block.

[0006] On the base portion, below the mass block, there is an electromagnet that can apply an attractive force to the mass block;

[0007] The accelerometer receives acceleration signals and transmits them to the processing system. The electromagnet converts the signals transmitted by the processing system into electromagnetic force and applies it to the mass block.

[0008] Furthermore, the formula by which the processing system converts acceleration information into electromagnetic force information is as follows:

[0009]

[0010] In the formula, F is the electromagnetic force; a is the acceleration amplitude measured by the accelerometer. m1 is the frequency measured by the accelerometer; m2 is the total mass of the main body, clamping device, and disc spring; m2 is the mass of the mass block; k2 is the stiffness of the compression spring; and t is time.

[0011] Furthermore, among the main body, sensor assembly, and disc spring, only the mass block is affected by the magnetic force of the electromagnet.

[0012] Furthermore, the sensor assembly includes an eddy current displacement sensor and a pressure plate for fixing the eddy current displacement sensor.

[0013] The present invention also discloses a method for expanding the vibration absorption frequency band of a vibration absorber, which includes applying an external force to a mass block by means of an electromagnet based on the above-mentioned absolute displacement measuring device for a vibration table, so that the device has a vibration absorption effect at each frequency of the vibration table.

[0014] The specific differential equation of motion for the two-degree-of-freedom undamped system is as follows:

[0015]

[0016] make , , ;

[0017] We can obtain:

[0018]

[0019]

[0020] In the formula, m1 is the total mass of the main body, clamping device and disc spring; m2 is the mass of the mass block; k1 is the stiffness of the disc spring; k2 is the stiffness of the cylindrical compression spring; x1 is the displacement of the main body; x2 is the displacement of the mass block; F is the electromagnetic force; F0 is the force applied by the vibration table to the base. A1 is the equivalent mass; A2 is the vibration amplitude of the main body; t is the vibration amplitude of the mass block; The frequency measured by the accelerometer;

[0021] The vibration amplitude A1 of the main body is 0, that is... When the value is 0, the dynamic vibration absorber achieves vibration damping; for different frequencies provided by the vibration table... Vibration, adjustment This keeps A1 at 0, eliminating the vibration of the main body 2 and the clamping device 3 at any frequency, and keeping the eddy current displacement sensor relatively stationary with respect to the ground.

[0022] Beneficial effects:

[0023] The beneficial effects of this invention compared to the prior art are as follows:

[0024] An active dynamic vibration absorber device reduces the error in the vibration amplitude values ​​of various components measured by sensors when the machine tool is tested on a vibration table. The active dynamic vibration absorber mainly consists of an electromagnet, an electromagnet support, a base, a cylindrical compression spring, and a mass block. The electromagnet provides electromagnetic force to the mass block. When the electromagnetic force reaches a certain level, all the vibration energy of the entire measuring device is transferred to the mass block, keeping the displacement sensor absolutely stationary, thereby reducing the error in the vibration amplitude values ​​of various components measured by sensors when the machine tool is tested on a vibration table. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the specific structure of the vibration table-specific absolute displacement measuring device in this invention;

[0026] Figure 2 This is a schematic diagram of the overall structure of the vibration table-specific absolute displacement measuring device in this invention.

[0027] Figure 3 This is a top view of the vibration table-specific absolute displacement measuring device in this invention;

[0028] Figure 4 This is a dynamic model diagram of the vibration table-specific absolute displacement measuring device in this invention. Detailed Implementation

[0029] To enhance understanding of the present invention, we will now describe it in further detail with reference to the accompanying drawings. These embodiments are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0030] like Figure 1-4 As shown, the vibration table-specific absolute displacement measuring device of the present invention includes a base part 1 for fixing the device, a main body part 2 for eliminating vibration, a clamping device 3 for mounting sensors, and a processing system 5 for processing acceleration sensor signals.

[0031] The base part 1 includes a base 11, a cable tray 12, an electromagnet bracket 13, an electromagnet 14, and an acceleration sensor 15; the base part 1 is connected to the main body part 2 via a disc spring 4; the main body part 2 includes a supporting body 21, a mass block 22, and a cylindrical compression spring 23; the clamping device 3 is located on the upper part of the main body part 2; the clamping device 3 includes an eddy current displacement sensor 31 for measuring displacement, a screw 32, and a pressure plate 33;

[0032] Electromagnet 14 is mounted on the upper surface of electromagnet bracket 13; electromagnet bracket 13 is threadedly connected to base 11;

[0033] The lower part of the cylindrical compression spring 23 is connected to the mass block 22; the upper part of the cylindrical compression spring 23 is connected to the clamping device 3.

[0034] The pressure plate 33 and screw 32 connect the eddy current displacement sensor 31 to the main body 2;

[0035] Of the main body 2, clamping device 3, and disc spring 4, only mass block 22 is made of the material affected by the magnetic force of electromagnet 14.

[0036] When in use, the special absolute displacement measuring device for this vibration table is placed on the device to be measured. The acceleration sensor 15 measures the acceleration signal of the device to be measured and transmits it to the processing system 5. The electromagnet 14 converts the signal transmitted by the processing system 5 into an electromagnetic force and applies it to the mass block 22.

[0037] An external force is applied to the mass block 22 by the electromagnet 14, so that the device has a vibration absorption effect at all frequencies of the vibration table; the specific formula is:

[0038] The differential equation of motion for a two-degree-of-freedom undamped system is:

[0039] ;

[0040] make , , ;

[0041] We can obtain:

[0042] ; ;

[0043] Where: m1 is the total mass of the supporting body 21, the clamping device 3, and the disc spring 4; m2 is the mass of the mass block 22; k1 is the stiffness of the disc spring 4; k2 is the stiffness of the cylindrical compression spring 23; x1 is the displacement of the main body 2; x2 is the displacement of the mass block 22; F is the electromagnetic force; F0 is the force applied by the vibration table to the base part 1; A1 represents the vibration amplitude of the supporting body 21; A2 represents the vibration amplitude of the mass block 22; t represents time. The frequency measured by accelerometer 15;

[0044] The expression for the amplitude F0 of the external force F0 exerted on the base part 1 by the vibration table is: ;

[0045] The formula by which processing system 5 converts acceleration information into electromagnetic force information is: Where: a is the acceleration amplitude measured by the accelerometer 15.

[0046] A method for expanding the vibration absorption bandwidth of a vibration absorber, wherein the vibration amplitude A1 of the main body 2 is 0, i.e. When the value is 0, the dynamic vibration absorber achieves its vibration damping effect. This applies to different frequencies provided by the vibration table. Vibration, adjustment By keeping A1 at 0, the vibration of the main body 2 and the clamping device 3 can be eliminated at any frequency. By keeping the eddy current displacement sensor 15 relatively stationary with respect to the ground, the absolute displacement of the device under test can be measured.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the specific embodiments described above. The specific embodiments and descriptions in the specification are merely for further illustrating the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the claims and their equivalents.

Claims

1. A vibration table-specific absolute displacement measuring device, comprising a base portion (1), a main body portion (2) disposed on the base portion (1), an acceleration sensor (15), and a processing system (5) for processing the acceleration sensor signal; the top of the main body portion (2) is provided with a clamping device (3), the clamping device (3) comprising an eddy current displacement sensor (31) for measuring displacement, a screw (32), and a pressure plate (33); characterized in that: The base part (1) is connected to the main body part (2) by a disc spring (4); A compression spring (23) is provided inside the main body (2) along the length of the main body (2); one end of the compression spring (23) is connected to the upper end of the main body (2), and the other end is connected to the mass block (22). On the base portion (1), an electromagnet (14) is provided below the mass block (22) to apply a suction force to the mass block (22). The acceleration sensor (15) transmits the acceleration signal to the processing system (5), and the electromagnet (14) converts the signal transmitted by the processing system (5) into an electromagnetic force and applies it to the mass block (22).

2. The absolute displacement measuring device for vibration table as described in claim 1, characterized in that: The formula by which the processing system (5) converts acceleration information into electromagnetic force information is: ； In the formula, F is the electromagnetic force; a is the acceleration amplitude measured by the accelerometer (15); m1 is the frequency measured by the accelerometer (15); m2 is the total mass of the main body (2), the clamping device (3) and the disc spring (4); m2 is the mass of the mass block (22); k2 is the stiffness of the compression spring (23); t is the time.

3. The absolute displacement measuring device for vibration table as described in claim 1, characterized in that: Of the main body (2), clamping device (3) and disc spring (4), only the mass block (22) is affected by the magnetic force of the electromagnet (14).

4. A method for expanding the vibration absorption bandwidth of a vibration absorber, characterized in that: Based on the vibration table-specific absolute displacement measuring device described in any of claims 1-3, an external force is applied to the mass block (22) by an electromagnet (14), so that the device has a vibration absorption effect at each frequency of the vibration table; The specific differential equation of motion for the two-degree-of-freedom undamped system is as follows: ； make , , ; We can obtain: ； ； In the formula, m1 is the total mass of the main body (2), the clamping device (3) and the disc spring (4); m2 is the mass of the mass block (22); k1 is the stiffness of the disc spring (4); k2 is the stiffness of the cylindrical compression spring (23); x1 is the displacement of the main body (2); x2 is the displacement of the mass block (22); F is the electromagnetic force; F0 is the force applied by the vibration table to the base part (1); A1 is the vibration amplitude of the main body (2); A2 is the vibration amplitude of the mass block (22); t represents time; The frequency is measured by the accelerometer (15); The vibration amplitude A1 of the main body (2) is 0, that is When the value is 0, the dynamic vibration absorber achieves vibration damping; for different frequencies provided by the vibration table... Vibration, adjustment This keeps A1 at 0, eliminating the vibration of the main body (2) and the clamping device (3) at any frequency, and keeping the clamping device (3) relatively stationary with respect to the ground.

Images