Micro-vibration measurement and calibration method for large-scale high-gravity rotating mechanical structures

Abstract

The present invention discloses a micro-vibration measurement and calibration method for a large-scale super-gravity rotating mechanical structure. First, the frequency domain amplitude caused by electromagnetic interference is calculated, and then a vibration equation model of the large-scale super-gravity rotating mechanical structure is constructed to solve the real acceleration caused by micro-vibration, and the real acceleration of micro-vibration at different heights is corrected, and finally a sensor calibration equation is constructed to solve the real value of the acceleration sensor to be calibrated. The present invention can measure and calibrate acceleration sensors positioned at different heights in a hanging basket of a large-scale super-gravity rotating mechanical structure, and improve the accuracy of the acceleration sensor measurement data in a super-gravity environment.

Description

Technical Field

[0001] The invention relates to the field of ultra-gravity centrifugal technology, in particular to a micro-vibration measurement and calibration method for a large ultra-gravity rotating mechanical structure. Background Art

[0002] At present, large-scale ultra-gravity rotating mechanical structures will produce micro-vibrations during high-speed rotation. The main reason is that the machine cannot achieve complete balance at the test end and the counterweight end. As the speed continues to increase, the unbalanced force will become larger and larger, and the vibration will become larger and larger. The mechanical parts of large-scale ultra-gravity rotating mechanical structures will wear and age during long-term operation, resulting in increased matching clearance or increased surface roughness, causing micro-vibrations, which are mechanical vibrations. At the same time, due to the uneven distribution of electromagnetic force or electromagnetic interference in large-scale ultra-gravity rotating mechanical structures, micro-vibrations between the rotor and the stator may also be caused. This micro-vibration is vibration caused by electromagnetic interference.

[0003] The micro-vibration caused by the rotation of large-scale ultra-gravity rotating mechanical structures will have a great impact on some precision test operations (such as microscope operation under ultra-gravity) or sensor measurements in the hanging baskets on both sides. At present, in an ultra-gravity environment, the acceleration generated by the micro-vibration itself has a great impact on resistive, capacitive, and piezoresistive MEMS acceleration sensors, and it is impossible to directly determine whether the micro-vibration is mainly caused by electromagnetic interference or mechanical vibration. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a micro-vibration measurement and calibration method for a large-scale ultra-gravity rotating mechanical structure, which can measure and calibrate acceleration sensors positioned at different heights in a hanging basket of a large-scale ultra-gravity rotating mechanical structure, thereby improving the accuracy of acceleration sensor measurement data in an ultra-gravity environment.

[0005] The technical solution of the present invention is:

[0006] The micro-vibration measurement and calibration method of a large-scale ultra-gravity rotating mechanical structure specifically includes the following steps:

[0007] (1) First, acceleration sensors at different heights are set in the hanging basket of a large-scale ultra-gravity rotating mechanical structure, and then the large-scale ultra-gravity rotating mechanical structure is started to rotate. The acceleration sensors at different heights collect frequency domain amplitude signals in real time. Since the frequency domain amplitude signals collected by the acceleration sensors at different heights are caused by electromagnetic interference and mechanical vibration, the frequency domain amplitude changes caused by electromagnetic interference to the acceleration sensors at different heights are equal, and the ratio of the frequency domain amplitude changes caused by mechanical vibration to the acceleration sensors at different heights is equal to the ratio of the square of the height. Thus, an equation is established to solve the frequency domain amplitude Y caused by electromagnetic interference. em(f);

[0008] (2) Construct a vibration equation model for a large-scale supergravity rotating mechanical structure, as shown in the following formula:

[0009] (3), according to equation (3), we can get the true acceleration in the horizontal direction: and the true acceleration in the vertical direction

[0010]

[0011] In formula (3), m represents the mass of the counterweight in the basket of the large-scale supergravity rotating mechanical structure; Represents the true speed in the horizontal direction, The derivative is obtained; Represents the true velocity in the vertical direction, given by Taking the derivative, we get: x(t) represents the real displacement in the horizontal direction, which is given by Derived; y(t) represents the true displacement in the vertical direction, which is obtained by The derivative is obtained; represents the comprehensive damping coefficient of the large-scale super-gravity rotating mechanical structure; k represents the stiffness of the large-scale super-gravity rotating mechanical structure, and its value is 10 7 ~10 9 ;k xy Represents the coupling stiffness coefficient in the horizontal direction, that is, the coupling effect of the y direction on the x direction, and its value is 10 6 ~10 7 ;k yx It represents the coupling stiffness coefficient in the vertical direction, that is, the coupling effect of the x direction on the y direction, and its value is 10 6 ~10 7 ;m u represents the unbalanced weight, with a value of 0 to 10 tons; ω represents the rotational angular velocity of the large-scale super-gravity rotating mechanical structure; L represents the arm length of the large-scale super-gravity rotating mechanical structure; e represents the eccentricity of the rotating shaft of the large-scale super-gravity rotating mechanical structure; g represents the acceleration of gravity; Y em (t) represents the time domain signal caused by electromagnetic interference, and the frequency domain amplitude Y caused by electromagnetic interference em (f) converted;

[0012] (3) Place a model box in the hanging basket of a large-scale supergravity rotating mechanical structure. The height of the model box is H, and the acceleration at the bottom of the model box is α. 底 , α 底 Including the true acceleration in the horizontal direction and the true acceleration in the vertical direction The correction equation is constructed to solve the acceleration at any height z in the model box as α(z), as shown in the following equation (4):

[0013]

[0014] In formula (4), n is the attenuation index of micro-vibration with height change, which takes the value of 1 or 2;

[0015] (4) The measured value of the acceleration sensor to be calibrated in the hanging basket of the large-scale ultra-gravity rotating mechanical structure is P 测 (z, t), construct the sensor calibration equation to solve the true value P of the acceleration sensor to be calibrated 真 (z, t), see the following formula (5):

[0016] P 测 (z,t)=P 真 (z,t)+ρα(z) (5);

[0017] In formula (5), ρ is the correction coefficient, which reflects the sensitivity of the accelerometer to be calibrated to micro-vibration and has a value of 0.5 to 1.

[0018] The frequency domain amplitude Y caused by the electromagnetic interference em The solution process of (f) is as follows: first, a counterweight is set in the hanging basket of the large-scale ultra-gravity rotating mechanical structure, an L-shaped plate is connected to the top surface of the counterweight, and three acceleration sensors at different horizontal heights are connected to the vertical part of the L-shaped plate. The three acceleration sensors are respectively a first acceleration sensor adjacent to the bottom end of the vertical part of the L-shaped plate, a third acceleration sensor adjacent to the top end of the vertical part of the L-shaped plate, and a second acceleration sensor located between the first acceleration sensor and the third acceleration sensor. The vertical distance between the first acceleration sensor and the top surface of the counterweight is L1, the vertical distance between the second acceleration sensor and the top surface of the counterweight is L2, and the vertical distance between the third acceleration sensor and the top surface of the counterweight is L3. Then, the large-scale ultra-gravity rotating mechanical structure is rotated, and the first acceleration sensor, the second acceleration sensor, and the third acceleration sensor record frequency domain signals in real time. The frequency domain amplitudes of the electromagnetic interference of the first acceleration sensor, the second acceleration sensor, and the third acceleration sensor are all set to Y. em (f), the frequency domain amplitudes of mechanical vibration are Y1(f), Y2(f) and Y3(f) respectively, and then the equation is established, as shown in the following formula (1):

[0019]

[0020] In formula (1), Y 实1 (f) Y 实2 (f) and Y 实3(f) are the frequency domain signals recorded in real time by the first acceleration sensor, the second acceleration sensor and the third acceleration sensor respectively. The frequency domain amplitudes Y1(f), Y2(f) and Y3(f) of the mechanical vibrations of the acceleration sensors at different heights satisfy the following formula (2);

[0021]

[0022] In formula (2), β is the vibration constant to be solved;

[0023] Then substitute equation (2) into equation (1) to obtain the vibration constant β and the frequency domain amplitude Y of the electromagnetic interference: em (f).

[0024] The first acceleration sensor, the second acceleration sensor and the third acceleration sensor are all multiple, that is, three rows of acceleration sensors are connected to the vertical part of the L-shaped plate, Y 实1 (f) is the average value of the frequency domain signals recorded in real time by multiple first acceleration sensors located at the same height, Y 实2 (f) is the average value of the frequency domain signals recorded in real time by multiple second acceleration sensors located at the same height, Y 实3 (f) is the average value of frequency domain signals recorded in real time by multiple third acceleration sensors located at the same height.

[0025] The It is calculated by the following formula (6):

[0026]

[0027] In formula (6), f0 represents the linear damping coefficient, which ranges from 1 to 10; c1 and c2 are the nonlinear damping coefficients, which range from 0.1 to 10.

[0028] The acceleration sensor to be calibrated is an IEPE acceleration sensor.

[0029] Advantages of the present invention:

[0030] (1) For mechanical vibration, as the height of the acceleration sensor in the hanging basket of a large-scale ultra-gravity rotating mechanical structure increases, the vibration amplitude will be amplified; while the vibration caused by electromagnetic interference has basically the same response amplitude for acceleration sensors at different heights, because electromagnetic interference is an interference signal in the environment and has the same impact on acceleration sensors at different positions. Based on the above principle, an equation is established to solve the frequency domain amplitude of electromagnetic interference and the frequency domain amplitude of mechanical vibration, and the main cause of micro-vibration is obtained.

[0031] (2) The present invention constructs a vibration equation model based on the different modes of the arm of the large-scale supergravity rotating mechanical structure to solve the real acceleration under micro-vibration, which is convenient for correcting the real acceleration under micro-vibration of different heights, and finally establishes a sensor calibration equation to realize the calibration of the acceleration sensor measurement value, thereby eliminating the interference of vibration on the experimental measurement and ensuring the accuracy of the acceleration sensor reading. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the L-shaped plate of the present invention connected to the counterweight block.

[0033] Figure 2 It is a schematic diagram of the structure of acceleration sensors at different heights on an L-shaped plate of the present invention.

[0034] Figure 3 It is a structural schematic diagram of the counterweight block of the present invention being placed in a hanging basket of a large-scale supergravity rotating mechanical structure.

[0035] Figure numerals: 1-hanging basket, 2-counterweight, 3-L-shaped plate, 4-first acceleration sensor, 5-second acceleration sensor, 6-third acceleration sensor. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] The micro-vibration measurement and calibration method of a large-scale ultra-gravity rotating mechanical structure specifically includes the following steps:

[0038] (1) See Figure 1-Figure 3First, a counterweight block 2 is set in a hanging basket 1 of a large-scale ultra-gravity rotating mechanical structure, and an L-shaped plate 3 is connected to the top surface of the counterweight block 2 by bolts. Three rows of acceleration sensors located at different horizontal heights are connected to the vertical part of the L-shaped plate 3. The three rows of acceleration sensors are respectively a row of first acceleration sensors 4 adjacent to the bottom end of the vertical part of the L-shaped plate 3, a row of third acceleration sensors 6 adjacent to the top end of the vertical part of the L-shaped plate 3, and a row of second acceleration sensors 5 located between the row of first acceleration sensors 4 and the row of third acceleration sensors 6. Each row of acceleration sensors includes There are four acceleration sensors, the vertical distance between the first acceleration sensor 4 and the top surface of the counterweight block 2 is L1, the vertical distance between the second acceleration sensor 5 and the top surface of the counterweight block 2 is L2, and the vertical distance between the third acceleration sensor 6 and the top surface of the counterweight block 2 is L3. Then the large-scale ultra-gravity rotating mechanical structure is rotated, and the first acceleration sensor 4, the second acceleration sensor 5 and the third acceleration sensor 6 record the frequency domain signal in real time, and the frequency domain amplitude of the first acceleration sensor 4, the second acceleration sensor 5 and the third acceleration sensor 6 subjected to electromagnetic interference is set to Y em (f), the frequency domain amplitudes of mechanical vibration are Y1(f), Y2(f) and Y3(f) respectively, and then the equation is established, as shown in the following formula (1):

[0039]

[0040] In formula (1), Y 实1 (f) Y 实2 (f) and Y 实3 (f) are frequency domain signals recorded in real time by the first acceleration sensor 4, the second acceleration sensor 5 and the third acceleration sensor 6; Y 实1 (f) is the average value of the frequency domain signals recorded in real time by four first acceleration sensors 4 located at the same height, Y 实2 (f) is the average value of the frequency domain signals recorded in real time by four second acceleration sensors 5 located at the same height, Y 实3 (f) is the average value of the frequency domain signals recorded in real time by four third acceleration sensors 6 located at the same height, satisfying the following formula (2);

[0041]

[0042] In formula (2), β is the vibration constant to be solved;

[0043] Then substitute equation (2) into equation (1) to obtain the vibration constant β and the frequency domain amplitude Y of the electromagnetic interference: em (f)

[0044] (2) Construct a vibration equation model for a large-scale supergravity rotating mechanical structure, as shown in the following formula:

[0045] (3), according to equation (3), we can get the true acceleration in the horizontal direction: and the true acceleration in the vertical direction

[0046]

[0047] In formula (3), m represents the mass of the counterweight in the basket of the large-scale supergravity rotating mechanical structure; Represents the true speed in the horizontal direction, The derivative is obtained; Represents the true velocity in the vertical direction, given by Taking the derivative, we get: x(t) represents the real displacement in the horizontal direction, which is given by Derived; y(t) represents the true displacement in the vertical direction, which is obtained by Derived, k represents the stiffness of the large-scale supergravity rotating mechanical structure, and its value is 10 7 ~10 9 ;k xy Represents the coupling stiffness coefficient in the horizontal direction, that is, the coupling effect of the y direction on the x direction, and its value is 10 6 ~10 7 ;k yx It represents the coupling stiffness coefficient in the vertical direction, that is, the coupling effect of the x direction on the y direction, and its value is 10 6 ~10 7 ;m u represents the unbalanced weight, with a value of 0 to 10 tons; ω represents the rotational angular velocity of the large-scale super-gravity rotating mechanical structure; L represents the arm length of the large-scale super-gravity rotating mechanical structure; e represents the eccentricity of the rotating shaft of the large-scale super-gravity rotating mechanical structure; g represents the acceleration of gravity; Y em (t) represents the time domain signal caused by electromagnetic interference, and the frequency domain amplitude Y caused by electromagnetic interference em (f) converted; The comprehensive damping coefficient of the large-scale supergravity rotating mechanical structure is calculated by the following formula (6):

[0048]

[0049] In formula (6), c0 represents the linear damping coefficient, which ranges from 1 to 10, c1 and c2 are nonlinear damping coefficients, which range from 0.1 to 10;

[0050] (3) Place a model box in the hanging basket of a large-scale supergravity rotating mechanical structure. The height of the model box is H, and the acceleration at the bottom of the model box is α. 底 , α 底 Including the true acceleration in the horizontal direction and the true acceleration in the vertical direction The correction equation is constructed to solve the acceleration at any height z in the model box as α(z), as shown in the following equation (4):

[0051]

[0052] In formula (4), n is the attenuation index of micro-vibration with height change, which takes the value of 1 or 2;

[0053] (4) The measured value of the acceleration sensor (resistive, capacitive or piezoresistive) to be calibrated in the hanging basket of a large-scale ultra-gravity rotating mechanical structure is P 测 (z, t), construct the sensor calibration equation to solve the true value P of the acceleration sensor to be calibrated 真 (z, t), see the following formula (5):

[0054] P 测 (z,t)=P 真 (z,t)+ρα(z) (5);

[0055] In formula (5), ρ is the correction coefficient, which reflects the sensitivity of the accelerometer to be calibrated to micro-vibration and has a value of 0.5 to 1.

[0056] Example

[0057] In the case of a large ultra-gravity rotating mechanical structure (ultra-gravity centrifuge) with a centrifugal range of 150g, the vertical distance between the first acceleration sensor of the L-shaped plate and the top surface of the counterweight block is L1=5cm, the vertical distance between the second acceleration sensor and the top surface of the counterweight block is L2=10cm, and the vertical distance between the third acceleration sensor and the top surface of the counterweight block is L3=15cm. The real-time measured Y 实1 (f) is approximately 0.07 g, Y 实2 (f) is approximately 0.22 g, Y 实3 (f) approximately 0.47 g;

[0058] From equation (1) and equation (2), we can get: Thus, we can solve β = 0.002, Y em (f)=0.02, that is, the frequency domain amplitude of electromagnetic interference is 0.02, and the frequency domain amplitudes of mechanical vibration at different heights are 0.05, 0.2, and 0.45 respectively, that is, the influence of mechanical vibration is large and the electromagnetic interference is small.

[0059] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A micro-vibration measurement and calibration method for a large-scale ultra-gravity rotating mechanical structure, characterized in that: The specific steps include: (1) First, acceleration sensors at different heights are set in the hanging basket of a large-scale ultra-gravity rotating mechanical structure, and then the large-scale ultra-gravity rotating mechanical structure is started to rotate. The acceleration sensors at different heights collect frequency domain amplitude signals in real time. Since the frequency domain amplitude signals collected by the acceleration sensors at different heights are caused by electromagnetic interference and mechanical vibration, the frequency domain amplitude changes caused by electromagnetic interference to the acceleration sensors at different heights are equal, and the ratio of the frequency domain amplitude changes caused by mechanical vibration to the acceleration sensors at different heights is equal to the ratio of the square of the height. Thus, an equation is established to solve the frequency domain amplitude Y caused by electromagnetic interference. em (f); (2) Construct a vibration equation model of a large-scale supergravity rotating mechanical structure, as shown in the following formula (3). The true acceleration in the horizontal direction is obtained by solving formula (3): and the true acceleration in the vertical direction In formula (3), m represents the mass of the counterweight in the basket of the large-scale supergravity rotating mechanical structure; Represents the true speed in the horizontal direction, The derivative is obtained; Represents the true velocity in the vertical direction, given by Derivatively, x(t) represents the real displacement in the horizontal direction, which is obtained by Derived; y(t) represents the true displacement in the vertical direction, which is obtained by The derivative is obtained; represents the comprehensive damping coefficient of the large-scale super-gravity rotating mechanical structure; k represents the stiffness of the large-scale super-gravity rotating mechanical structure, and its value is 10 7 ~10 9 ;k xy Represents the coupling stiffness coefficient in the horizontal direction, that is, the coupling effect of the y direction on the x direction, and its value is 10 6 ~10 7 ;k yx It represents the coupling stiffness coefficient in the vertical direction, that is, the coupling effect of the x direction on the y direction, and its value is 10 6 ~10 7 ; m u represents the unbalanced weight, with a value of 0 to 10 tons; ω represents the rotational angular velocity of the large-scale super-gravity rotating mechanical structure; L represents the arm length of the large-scale super-gravity rotating mechanical structure; e represents the eccentricity of the rotating shaft of the large-scale super-gravity rotating mechanical structure; g represents the acceleration of gravity; Y em (t) represents the time domain signal caused by electromagnetic interference, and the frequency domain amplitude Y caused by electromagnetic interference em (f) converted; (3) Place a model box in the hanging basket of a large-scale supergravity rotating mechanical structure. The height of the model box is H, and the acceleration at the bottom of the model box is α. 底 , α 底 Including the true acceleration in the horizontal direction and the true acceleration in the vertical direction The correction equation is constructed to solve the acceleration at any height z in the model box as α(z), as shown in the following equation (4): In formula (4), n is the attenuation index of micro-vibration with height change, which takes the value of 1 or 2; (4) The measured value of the acceleration sensor to be calibrated in the hanging basket of the large-scale ultra-gravity rotating mechanical structure is P 测 (z, t), construct the sensor calibration equation to solve the true value P of the acceleration sensor to be calibrated 真 (z, t), see the following formula (5): P 测 (z,t)=P 真 (z,t)+ρα(z) (5); In formula (5), ρ is the correction coefficient, which reflects the sensitivity of the accelerometer to be calibrated to micro-vibration and has a value of 0.5 to 1.

2. The micro-vibration measurement and calibration method of a large-scale ultra-gravity rotating mechanical structure according to claim 1 is characterized in that: The frequency domain amplitude Y caused by the electromagnetic interference em The solution process of (f) is as follows: first, a counterweight is set in the hanging basket of the large-scale ultra-gravity rotating mechanical structure, an L-shaped plate is connected to the top surface of the counterweight, and three acceleration sensors at different horizontal heights are connected to the vertical part of the L-shaped plate. The three acceleration sensors are respectively a first acceleration sensor adjacent to the bottom end of the vertical part of the L-shaped plate, a third acceleration sensor adjacent to the top end of the vertical part of the L-shaped plate, and a second acceleration sensor located between the first acceleration sensor and the third acceleration sensor. The vertical distance between the first acceleration sensor and the top surface of the counterweight is L1, the vertical distance between the second acceleration sensor and the top surface of the counterweight is L2, and the vertical distance between the third acceleration sensor and the top surface of the counterweight is L3. Then, the large-scale ultra-gravity rotating mechanical structure is rotated, and the first acceleration sensor, the second acceleration sensor, and the third acceleration sensor record frequency domain signals in real time. The frequency domain amplitudes of the electromagnetic interference of the first acceleration sensor, the second acceleration sensor, and the third acceleration sensor are all set to Y. em (f), the frequency domain amplitudes of mechanical vibration are Y1(f), Y2(f) and Y3(f) respectively, and then the equation is established, as shown in the following formula (1): In formula (1), Y 实1 (f) Y 实2 (f) and Y 实3 (f) are the frequency domain signals recorded in real time by the first acceleration sensor, the second acceleration sensor and the third acceleration sensor respectively. The frequency domain amplitudes Y1(f), Y2(f) and Y3(f) of the mechanical vibrations of the acceleration sensors at different heights satisfy the following formula (2); In formula (2), β is the vibration constant to be solved; Then substitute equation (2) into equation (1) to obtain the vibration constant β and the frequency domain amplitude Y of the electromagnetic interference: em (f).

3. The micro-vibration measurement and calibration method of a large-scale ultra-gravity rotating mechanical structure according to claim 2, characterized in that: The first acceleration sensor, the second acceleration sensor and the third acceleration sensor are all multiple, that is, three rows of acceleration sensors are connected to the vertical part of the L-shaped plate, Y 实1 (f) is the average value of the frequency domain signals recorded in real time by multiple first acceleration sensors located at the same height, Y 实2 (f) is the average value of the frequency domain signals recorded in real time by multiple second acceleration sensors located at the same height, Y 实3 (f) is the average value of frequency domain signals recorded in real time by multiple third acceleration sensors located at the same height.

4. The micro-vibration measurement and calibration method of a large-scale ultra-gravity rotating mechanical structure according to claim 1, characterized in that: The It is calculated by the following formula (6): In formula (6), c0 represents the linear damping coefficient, which ranges from 1 to 10; c1 and c2 are the nonlinear damping coefficients, which range from 0.1 to 10.

5. The micro-vibration measurement and calibration method of a large-scale ultra-gravity rotating mechanical structure according to claim 1, characterized in that: The acceleration sensor to be calibrated is an IEPE acceleration sensor.

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