Mould vibration data calibration method and system

Abstract

The application discloses a kind of crystallizer vibration data calibration method and system, comprising: S1. to three-axis acceleration sensor is factory calibration, obtain the three-axis acceleration sensor after calibration;S2. the three-axis acceleration sensor after calibration is fixed in crystallizer vibration platform, the coordinate value of the three-axis unit vector of sensor is calculated in stationary state;S3. based on the coordinate value of the three-axis unit vector of sensor, it is calculated and obtained three-axis acceleration measurement value after calibration.The application does not need to introduce additional sensor or measurement module, easy to implement and applicable to various scenes, guarantee the monitoring precision of crystallizer vibration.

Description

Technical Field

[0001] This invention relates to the field of crystallizer vibration, and more specifically to a method and system for calibrating crystallizer vibration data. Background Technology

[0002] The crystallizer is a copper tube and auxiliary component that receives molten steel and solidifies it into a billet according to a specified cross-sectional shape. It is an important part of the continuous casting machine. The function of crystallizer vibration is to prevent the billet from sticking to the copper wall of the crystallizer during solidification, reduce the resistance during billet pulling, and improve the surface quality of the billet. If the vibration effect is not up to standard, defects may occur on the surface of the billet, affecting the performance of the final rolled steel. In severe cases, it may even lead to steel leakage accidents. Therefore, it is necessary to monitor and analyze the vibration status of the crystallizer to provide reliable guidance for the production, operation, and maintenance of continuous casting.

[0003] Many crystallizer vibration monitoring products on the market primarily use triaxial accelerometers to collect crystallizer vibration data. Displacement is obtained by filtering and integrating the acceleration, and then the crystallizer's vibration state parameters are derived based on the displacement. However, although triaxial accelerometers can be calibrated at the factory, an error caused by installation still exists: triaxial accelerometers are typically fixed to the crystallizer vibration platform, which is not perfectly horizontal. This causes the sensitive axis of the triaxial accelerometer to be misaligned with the direction to be measured (the direction of gravitational acceleration and the two perpendicular directions on the horizontal plane), resulting in measurement deviation. This error is a non-orthogonal installation error and cannot be calibrated before leaving the factory.

[0004] To address the aforementioned measurement deviation issue, patent CN 215374205 U discloses a novel crystallizer vibration detector. This detector combines a gyroscope sensor module with a triaxial accelerometer to measure the carrier's acceleration, angular velocity, displacement, and vibration frequency, avoiding measurement accuracy distortion caused by the device not being leveled. This patent incorporates a bubble level into traditional crystallizer vibration monitors, using the bubble level and height adjustment feet to ensure levelness. However, the aforementioned patent's additional use of gyroscopes and bubble levels makes the detection process more complex and consumes more manpower and resources.

[0005] Therefore, to solve the above measurement deviation problem, a new technical solution is needed that can eliminate the measurement error caused by the triaxial accelerometer not being installed on a horizontal plane. This solution does not require the introduction of additional sensors or measurement modules, is easy to implement, and is applicable to various scenarios, thus ensuring the monitoring accuracy of crystallizer vibration. Summary of the Invention

[0006] In view of this, the purpose of this invention is to overcome the defects in the prior art and provide a method and system for calibrating crystallizer vibration data. It does not require the introduction of additional sensors or measurement modules, is easy to implement and applicable to various scenarios, and ensures the monitoring accuracy of crystallizer vibration.

[0007] The crystallizer vibration data calibration method of the present invention includes the following steps:

[0008] S1. Perform factory calibration on the triaxial accelerometer to obtain the calibrated triaxial accelerometer;

[0009] S2. Fix the calibrated triaxial accelerometer to the crystallizer vibration platform and calculate the coordinate values ​​of the triaxial unit vector of the sensor in a static state;

[0010] S3. Based on the coordinate values ​​of the three-axis unit vector of the sensor, calculate the calibrated three-axis acceleration measurement value.

[0011] Furthermore, in step S2, the coordinate values ​​of the sensor's three-axis unit vector are calculated in a static state, specifically including:

[0012] S21. Let the sensor's spatial rectangular coordinate system be OXYZ, and the three-axis unit vectors be respectively... And it satisfies the right-hand rule, the triaxial measurement value in the static state is A. X A Y A Z ;

[0013] S22. If |A X |、|A Y |、|A Z If any one of the values ​​is close to gravitational acceleration and the remaining two are close to zero, then the sensor is already horizontal and does not require calibration; otherwise, proceed to step S23.

[0014] S23. Construct a spatial rectangular coordinate system OX1Y1Z1 based on OXYZ, with the three axis unit vectors as follows: And it satisfies the right-hand rule, and assumes In the same direction as the gravitational acceleration vector, Located in the +X1OZ1 plane, where +X1 represents the positive half-axis of the X1 axis; Rotate counterclockwise to The angle is θ;

[0015] S24. Let... The coordinates in the OX1Y1Z1 coordinate system are respectively Based on the relationship between OXYZ and OX1Y1Z1, the following equation can be written:

[0016]

[0017] Solving the above equation yields the coordinate values ​​R of the three-axis unit vector:

[0018]

[0019] Where G is the value of gravitational acceleration.

[0020] Furthermore, in step S22, |A is determined according to the following method. X |、|A Y |、|A Z Whether any one of them is close to gravitational acceleration and whether it is close to zero:

[0021] If ||X|-G| / G < 0.5%, then |X| is considered close to gravitational acceleration; if |X| / G < 0.5%, then |X| is considered close to zero; where |X| is |A X |、|A Y |、|A Z |Any one of them.

[0022] Furthermore, in step S3, the calibrated triaxial acceleration measurement values ​​are calculated, specifically including:

[0023] Let the triaxial acceleration measurement value under any condition be B. X B Y B Z And set the sensor's three-axis acceleration vectors at respectively The sum of the projection values ​​on is: The projected value is then the calibrated triaxial acceleration measurement value W.

[0024]

[0025] Furthermore, in step S3, the calibrated triaxial acceleration measurement values ​​are calculated, specifically including:

[0026] set up In the same direction as the gravitational acceleration vector, Located in the +Y1OZ1 plane, where +Y1 represents the positive half-axis of the Y1 axis. Rotate counterclockwise to If the angle is θ, then at this time The direction is In the projection direction on the horizontal plane, i.e., the measurement direction on the horizontal plane is highly correlated with the sensor's Y-axis direction, the coordinate value R of the three-axis unit vector becomes:

[0027]

[0028] The calibrated triaxial acceleration measurement value W is:

[0029]

[0030] Among them, the sensor's three-axis acceleration vectors are respectively in The sum of the projection values ​​on is: Let the triaxial acceleration measurement value under any condition be B. X B Y B Z .

[0031] A crystallizer vibration data calibration system includes a factory calibration unit, a triaxial unit vector unit, and an acceleration measurement unit;

[0032] The factory calibration unit is used to calibrate the triaxial accelerometer to obtain the calibrated triaxial accelerometer.

[0033] The triaxial unit vector unit is used to fix the calibrated triaxial accelerometer to the crystallizer vibration platform and calculate the coordinate values ​​of the triaxial unit vector of the sensor in a static state.

[0034] The acceleration measurement unit is used to calculate the calibrated triaxial acceleration measurement value based on the coordinate values ​​of the triaxial unit vector of the sensor.

[0035] Furthermore, the coordinate values ​​of the sensor's three-axis unit vector are calculated in a static state, specifically including:

[0036] S21. Let the sensor's spatial rectangular coordinate system be OXYZ, and the three-axis unit vectors be respectively... And it satisfies the right-hand rule, the triaxial measurement value in the static state is A. X A Y A Z ;

[0037] S22. If |A X |、|A Y |、|A Z If any one of the values ​​is close to gravitational acceleration and the remaining two are close to zero, then the sensor is already horizontal and does not require calibration; otherwise, proceed to step S23.

[0038] S23. Construct a spatial rectangular coordinate system OX1Y1Z1 based on OXYZ, with the three axis unit vectors as follows: And it satisfies the right-hand rule, and assumes In the same direction as the gravitational acceleration vector, Located in the +X1OZ1 plane, where +X1 represents the positive half-axis of the X1 axis; Rotate counterclockwise to The angle is θ;

[0039] S24. Let... The coordinates in the OX1Y1Z1 coordinate system are respectively Based on the relationship between OXYZ and OX1Y1Z1, the following equation can be written:

[0040]

[0041] Solving the above equation yields the coordinate values ​​R of the three-axis unit vector:

[0042]

[0043] Where G is the value of gravitational acceleration.

[0044] Furthermore, determine |A| using the following method. X |、|A Y |、|A Z Whether any one of them is close to gravitational acceleration and whether it is close to zero:

[0045] If ||X|-G| / G < 0.5%, then |X| is considered close to gravitational acceleration; if |X| / G < 0.5%, then |X| is considered close to zero; where |X| is |A X |、|A Y |、|A Z |Any one of them.

[0046] Furthermore, the calibrated triaxial acceleration measurements were calculated, specifically including:

[0047] Let the triaxial acceleration measurement value under any condition be B. X B Y B Z And set the sensor's three-axis acceleration vectors at respectively The sum of the projection values ​​on is: The projected value is then the calibrated triaxial acceleration measurement value W.

[0048]

[0049] Furthermore, the calibrated triaxial acceleration measurements were calculated, specifically including:

[0050] set up In the same direction as the gravitational acceleration vector, Located in the +Y1OZ1 plane, where +Y1 represents the positive half-axis of the Y1 axis. Rotate counterclockwise to If the angle is θ, then at this time The direction is In the projection direction on the horizontal plane, i.e., the measurement direction on the horizontal plane is highly correlated with the sensor's Y-axis direction, the coordinate value R of the three-axis unit vector becomes:

[0051]

[0052] The calibrated triaxial acceleration measurement value W is:

[0053]

[0054] Among them, the sensor's three-axis acceleration vectors are respectively in The sum of the projection values ​​on is: Let the triaxial acceleration measurement value under any condition be B. X B Y B Z .

[0055] The beneficial effects of this invention are as follows: The crystallizer vibration data calibration method and system disclosed in this invention first calibrates the triaxial accelerometer at the factory, ensuring that the sensor's measured values ​​accurately reflect the actual acceleration components along the sensitive axis. Then, after the triaxial accelerometer is fixed to the crystallizer vibration platform, in a static state, another spatial rectangular coordinate system is constructed based on the sensor's triaxial coordinate system. The three axes of this coordinate system represent the directions of the three acceleration components of interest in the crystallizer vibration monitoring application. The coordinate values ​​of the sensor's triaxial unit vector are then calculated. Subsequently, based on the sensor's triaxial unit vector coordinates, the calibrated acceleration measurement value is calculated, thereby eliminating measurement errors caused by the sensor not being installed on a horizontal plane. No additional sensors or measurement modules are required, making it widely applicable and easy to implement. Attached Figure Description

[0056] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0057] Figure 1 This is a schematic flowchart of the vibration data calibration method of the present invention;

[0058] Figure 2 This is a schematic diagram illustrating the implementation of the spatial rectangular coordinate system constructed by the present invention for solving the three-axis unit vector coordinate values ​​of the sensor;

[0059] Figure 3 This is a schematic diagram illustrating an implementation of another spatial rectangular coordinate system constructed by the present invention for solving the three-axis unit vector coordinate values ​​of the sensor. Detailed Implementation

[0060] The present invention will be further described below with reference to the accompanying drawings, as shown in the figures:

[0061] The crystallizer vibration data calibration method of the present invention includes the following steps:

[0062] S1. Perform factory calibration on the triaxial accelerometer to obtain a calibrated triaxial accelerometer. This includes calibrating the triaxial accelerometer's zero bias, sensitivity error, cross-axis sensitivity, non-orthogonal mounting error between the internal chip and the housing, temperature drift, etc., to ensure that the sensor's measurements accurately reflect the actual acceleration components along the sensitive axis. Existing calibration methods such as 6 / 12 / 24 position calibration based on a position turntable or ellipsoidal fitting can be used for factory calibration of the triaxial accelerometer.

[0063] S2. Fix the calibrated triaxial accelerometer to the crystallizer vibration platform and calculate the coordinate values ​​of the triaxial unit vector of the sensor in a static state;

[0064] S3. Based on the coordinate values ​​of the three-axis unit vector of the sensor, calculate the calibrated three-axis acceleration measurement value.

[0065] In this embodiment, in step S2, Figure 2 The following is a schematic diagram illustrating an embodiment of the present invention. The coordinate values ​​of the triaxial unit vector of the sensor are explained in conjunction with this diagram:

[0066] S21. Let the sensor's spatial rectangular coordinate system be OXYZ, and the three-axis unit vectors be respectively... And it satisfies the right-hand rule. Let the triaxial measurement value in the static state be A. X A Y A Z The measured values ​​have been filtered and noise interference has been eliminated. Methods such as averaging filtering, Kalman filtering, and wavelet filtering can be used.

[0067] The triaxial acceleration data was collected for 10 seconds while the object was stationary, and then the average value was taken. The result is: A X =2.920m / s 2 A Y =2.386m / s 2 A Z =9.045m / s 2 .

[0068] S22. If |A X |、|A Y |、|A Z If any one of the values ​​is close to gravitational acceleration and the other two are close to zero, then the sensor is already horizontal and does not need to be calibrated; otherwise, proceed to step S23.

[0069] Where ||X|-G| / G<0.5%, then |X| is considered close to gravitational acceleration; if |X| / G<0.5%, then |X| is considered close to zero, and |X| is |A. X |、|A Y |、|A Z | any one of them. Obviously, the embodiment does not meet this condition, so continue calibration and go to step S23.

[0070] S23. Construct a spatial rectangular coordinate system OX1Y1Z1 based on OXYZ, with the three axis unit vectors as follows: And it satisfies the right-hand rule, and assumes In the same direction as the gravitational acceleration vector, Located in the +X1OZ1 plane (the plane containing the positive half-axis of the X1 axis), and Rotate counterclockwise to Let the angle be θ. Clearly, we have:

[0071]

[0072] Where G is a gravitational acceleration value.

[0073] In specific implementation, the relative relationship between coordinate systems OXYZ and OX1Y1Z1 is as follows: Figure 2 As shown, G is based on the gravitational acceleration of the application location, and in this embodiment, the value is taken as 9.8 m / s². 2 In conclusion:

[0074]

[0075] S24. Calculation The coordinates in the OX1Y1Z1 coordinate system. Let... The coordinates are respectively Based on the relationship between OXYZ and OX1Y1Z1, the mutual relationship of the three-axis unit vectors—each pair of vectors being perpendicular and satisfying the right-hand rule—and the relationship between the three-axis unit vectors and gravitational acceleration, the following equations can be established:

[0076]

[0077] Solving the above equation yields:

[0078]

[0079] In specific implementation, the above A X A Y A Z Substituting equation (1.1) into equation (3) yields:

[0080]

[0081] In this embodiment, step S3 calculates the calibrated triaxial acceleration measurement value based on the coordinate values ​​of the sensor's triaxial unit vector, thereby eliminating the measurement error caused by the sensor not being installed on a horizontal plane. Specifically, this includes:

[0082] Let the triaxial acceleration measurement value under any condition be B. X B Y B Z And set the sensor's three-axis acceleration vectors at respectively The sum of the projected values: As shown in the following formula, this projected value is the calibrated triaxial acceleration measurement value W:

[0083]

[0084] Obviously, P Z1 Is it the actual acceleration at Measurement of the component of direction-gravitational acceleration. Is it the actual acceleration at —Measurement values ​​of components in two mutually perpendicular directions on a horizontal plane.

[0085] For crystallizer vibration monitoring applications, the measurement direction needs to be the direction of gravitational acceleration and two mutually perpendicular directions on the horizontal plane (many crystallizers have a rectangular cross-section on the horizontal plane, so this generally refers to the length and width directions of this rectangle). Actual monitoring will... Parallel to the two mutually perpendicular directions on the horizontal plane mentioned above, then This eliminates the measurement error caused by the triaxial accelerometer not being installed on a horizontal plane, as it measures acceleration in the required direction.

[0086] The above order or It is easy to make the plane parallel to two mutually perpendicular directions. For the OX1Y1Z1 constructed above, The direction is Since the projection direction on the horizontal plane is generally marked with XYZ axes on the sensor housing, the X-axis projection direction of the sensor should be aligned with the direction to be measured on the horizontal plane. Furthermore, in crystallizer vibration monitoring applications, the focus is on the maximum value of the vibration displacement on the horizontal plane—the runout—and the accuracy requirement for the measurement direction on the horizontal plane is not high.

[0087] In practice, let the measured triaxial acceleration value at a certain moment during the crystallizer vibration process be:

[0088] B X =3.421m / s 2 B Y=3.256m / s 2 B Z =9.564m / s 2 The calibrated triaxial acceleration measurement values ​​are:

[0089]

[0090] In this embodiment, in step S2, there are multiple ways to construct the spatial rectangular coordinate system OX1Y1Z1, and the construction method can be selected according to preference in practical applications. Regarding OX1Y1Z1 in step S2 above, The direction is The projection direction on the horizontal plane, i.e. the measurement direction on the horizontal plane, is highly correlated with the X-axis direction of the sensor.

[0091] If we assume In the same direction as the gravitational acceleration vector, Located in the +Y1OZ1 plane (the plane containing the positive half-axis of the Y1 axis), and Rotate counterclockwise to If the angle is θ, then at this time The direction is If the projection direction on the horizontal plane, i.e. the measurement direction on the horizontal plane, is highly correlated with the sensor's Y-axis direction, then:

[0092]

[0093]

[0094] In step S3, the calibrated triaxial acceleration measurement value W can also be calculated as follows:

[0095]

[0096] In practice, the relative relationship between coordinate systems OXYZ and OX1Y1Z1 is as follows: Figure 3 As shown, the above A X A Y A Z And B X B Y B Z Substituting, we get:

[0097]

[0098]

[0099]

[0100] Of course, there are countless ways to construct a spatial rectangular coordinate system OX1Y1Z1, because there are countless ways to construct two mutually perpendicular directions on a horizontal plane. This invention only lists the two simple and practically significant construction methods mentioned above. Other construction methods and the calculated calibrated triaxial acceleration measurement values ​​are based on the same or similar principles as the two methods mentioned above, and will not be elaborated here.

[0101] The present invention also relates to a crystallizer vibration data calibration system, which corresponds to the crystallizer vibration data calibration method described above and can be understood as a system for implementing the above method. The system includes a factory calibration unit, a three-axis unit vector unit, and an acceleration measurement unit.

[0102] The factory calibration unit is used to calibrate the triaxial accelerometer to obtain the calibrated triaxial accelerometer.

[0103] The triaxial unit vector unit is used to fix the calibrated triaxial accelerometer to the crystallizer vibration platform and calculate the coordinate values ​​of the triaxial unit vector of the sensor in a static state.

[0104] The acceleration measurement unit is used to calculate the calibrated triaxial acceleration measurement value based on the coordinate values ​​of the triaxial unit vector of the sensor.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for calibrating crystallizer vibration data, characterized in that: Includes the following steps: S1. Perform factory calibration on the triaxial accelerometer to obtain the calibrated triaxial accelerometer; S2. Fix the calibrated triaxial accelerometer to the crystallizer vibration platform and calculate the coordinate values ​​of the triaxial unit vector of the sensor in a static state; Calculating the coordinate values ​​of the sensor's three-axis unit vector in a static state includes: S21. Let the spatial rectangular coordinate system of the sensor be... The three-axis unit vectors are respectively , , And satisfying the right-hand rule, the triaxial measurement values ​​in the static state are , , ; S22. If , , If any one of the values ​​is close to gravitational acceleration and the remaining two are close to zero, then the sensor is placed horizontally and does not require calibration; otherwise, proceed to step S23. S23. In Construct a spatial rectangular coordinate system based on this. The three-axis unit vectors are respectively , , And satisfy the right-hand rule, and assume In the same direction as the gravitational acceleration vector, lie in In the plane, where, express Positive half-axis; Rotate counterclockwise to The angle is ; S24. Let... , , exist The coordinates in the coordinate system are respectively , , According to and The relationship can be expressed by the following equation: ； Solving the above equations yields the coordinates of the three-axis unit vector. : ； in, This is the value of gravitational acceleration; In step S22, the following method is used to determine... , , Whether any one of them is close to gravitational acceleration and whether it is close to zero: like Then it is believed Approaching gravitational acceleration, if Then it is believed Approaching zero; among which, for , , Any one of them; S3. Based on the coordinate values ​​of the three-axis unit vector of the sensor, calculate the calibrated three-axis acceleration measurement value.

2. The crystallizer vibration data calibration method according to claim 1, characterized in that: In step S3, the calibrated triaxial acceleration measurement values ​​are calculated, specifically including: Let the triaxial acceleration measurement value under any condition be... , , And set the sensor's three-axis acceleration vectors at respectively , , The sum of the projection values ​​on is: , , Then the projected value is the calibrated triaxial acceleration measurement value. : 。 3. The crystallizer vibration data calibration method according to claim 1, characterized in that: In step S3, the calibrated triaxial acceleration measurement values ​​are calculated, specifically including: set up In the same direction as the gravitational acceleration vector, lie in In the plane, where, express positive half-axis, Rotate counterclockwise to The angle is Then at this time The direction is The projection direction on the horizontal plane, i.e., the measurement direction on the horizontal plane and the sensor... If the axial directions are height-dependent, then the coordinate values ​​of the three-axis unit vectors are... It becomes: ； Calibrated triaxial acceleration measurements for: ； Among them, the sensor's three-axis acceleration vectors are respectively in , , The sum of the projection values ​​on is: , , Let the triaxial acceleration measurement value under any state be... , , .

4. A crystallizer vibration data calibration system, characterized in that: Includes factory calibration unit, triaxial unit vector unit, and acceleration measurement unit; The factory calibration unit is used to calibrate the triaxial accelerometer to obtain the calibrated triaxial accelerometer. The triaxial unit vector unit is used to fix the calibrated triaxial accelerometer to the crystallizer vibration platform and calculate the coordinate values ​​of the triaxial unit vector of the sensor in a static state. Calculating the coordinate values ​​of the sensor's three-axis unit vector in a static state includes: S21. Let the spatial rectangular coordinate system of the sensor be... The three-axis unit vectors are respectively , , And satisfying the right-hand rule, the triaxial measurement values ​​in the static state are , , ; S22. If , , If any one of the values ​​is close to gravitational acceleration and the remaining two are close to zero, then the sensor is placed horizontally and does not require calibration; otherwise, proceed to step S23. S23. In Construct a spatial rectangular coordinate system based on this. The three-axis unit vectors are respectively , , And satisfy the right-hand rule, and assume In the same direction as the gravitational acceleration vector, lie in In the plane, where, express Positive half-axis; Rotate counterclockwise to The angle is ; S24. Let... , , exist The coordinates in the coordinate system are respectively , , According to and The relationship can be expressed as the following equation: ； Solving the above equations yields the coordinates of the three-axis unit vector. : ； in, This is the value of gravitational acceleration; In step S22, the following method is used to determine... , , Whether any one of them is close to gravitational acceleration and whether it is close to zero: like Then it is believed Approaching gravitational acceleration, if Then it is believed Approaching zero; among which, for , , Any one of them; The acceleration measurement unit is used to calculate the calibrated triaxial acceleration measurement value based on the coordinate values ​​of the triaxial unit vector of the sensor.

5. The crystallizer vibration data calibration system according to claim 4, characterized in that: The calibrated triaxial acceleration measurements were calculated, including: Let the triaxial acceleration measurement value under any condition be... , , And set the sensor's three-axis acceleration vectors at respectively , , The sum of the projection values ​​on is: , , Then the projected value is the calibrated triaxial acceleration measurement value. : 。 6. The crystallizer vibration data calibration system according to claim 4, characterized in that: The calibrated triaxial acceleration measurements were calculated, including: set up In the same direction as the gravitational acceleration vector, lie in In the plane, where, express positive half-axis, Rotate counterclockwise to The angle is Then at this time The direction is The projection direction on the horizontal plane, i.e., the measurement direction on the horizontal plane and the sensor... If the axial directions are height-dependent, then the coordinate values ​​of the three-axis unit vectors are... It becomes: ； Calibrated triaxial acceleration measurements for: ； Among them, the sensor's three-axis acceleration vectors are respectively in , , The sum of the projection values ​​on is: , , Let the triaxial acceleration measurement value under any state be... , , .

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