An automatic flow limiting and frequency reducing device and method for a vibroflot

Abstract

This invention relates to an automatic current limiting and frequency reduction device and method for a vibratory impactor. The system includes a power supply, a data acquisition device, a drive motor, and a frequency converter. The data acquisition device is used to acquire the operating current I of the vibratory impactor in real time. The power supply is used to supply power to the drive motor, which drives the eccentric block inside the vibratory impactor to rotate. The frequency converter is used to control the operating frequency f of the drive motor according to the frequency conversion formula, where the frequency conversion formula is: where f is the operating frequency of the drive motor; n is the number of pole pairs of the drive motor; μ is the load coefficient of the drive motor; I is the operating current of the vibratory impactor; R is the resistance on the stator side of the drive motor; S is the slip ratio, where n, μ, R, and S are all provided by the manufacturers of the drive motor and the vibratory impactor; K is a correction coefficient, set by the user, and 0 < K < 1; F is the rated operating frequency of the drive motor; I 额定 This is the rated operating current of the vibratory impactor.

Description

Technical Field

[0001] This invention relates to the field of vibratory beater technology, and specifically to an automatic current limiting and frequency reduction device and method for vibratory beaters. Background Technology

[0002] A vibratory compactor is a specialized machine used in vibratory compaction construction. Its working principle involves a submersible motor driving an eccentric block within the vibrating body via a coupling, generating centrifugal force that causes the entire vibratory compactor to vibrate horizontally. Vibratory compactors can be used in the construction of vibratory compaction piles for filling and compaction. They are suitable for reinforcing foundations of gravelly soil, sandy soil, silty soil, cohesive soil, artificial fill, and collapsible soil, as well as for densifying and liquefying various liquefiable soils. Vibratory compaction treatment allows the soil to withstand certain dynamic loads, improving foundation bearing capacity, reducing settlement, increasing foundation stability, and enhancing resistance to earthquake liquefaction. Vibratory compactors can be used in the construction of new roadbeds to reinforce culvert foundations and loose sandy or soft clay soils to prevent sand liquefaction, improve foundation bearing capacity, and reduce post-construction settlement and uneven settlement. They can also be used to reinforce natural slopes or earth-rock dam slopes to improve slope stability.

[0003] In existing technology, when the oscillator encounters excessive load, the current rises sharply, and it trips and shuts down when it reaches the set upper limit. If the oscillator is not stopped by tripping, it will burn out. However, frequent tripping will affect working efficiency.

[0004] To avoid frequent tripping and shutdown of oscillators, Chinese patent application CN103439909A discloses a monitoring method for preventing repeated shutdowns of oscillators, comprising the following steps: 1) Installing a current and / or voltage monitoring device at each working oscillator to measure the working current I1 and / or working voltage U1 of the oscillator; 2) Installing a monitoring terminal, and simultaneously installing a wireless transceiver unit at each working oscillator, with each working oscillator communicating wirelessly with the monitoring terminal through the wireless transceiver unit; 3) The monitoring terminal is equipped with a primary processing unit and a secondary processing unit. Each working vibratory oscillator transmits information to the monitoring terminal via a wireless transceiver unit, and then connects to the primary processing unit and the secondary processing unit in sequence. The rated voltage U, rated current I, and maximum limit working time t of the vibratory oscillator are set. If I1>I or U1>U as measured in step 1), the primary processing unit starts timing t1. If t1≥t, the primary processing unit transmits the information to the secondary processing unit, and the secondary processing unit controls the vibratory oscillator that has exceeded the limit working time to stop working. If t1<t, the primary processing unit does not transmit the information to the secondary processing unit, and the vibratory oscillator continues to work.

[0005] While the above solution can avoid accidental and repeated shutdowns of the vibratory compactor due to incorrect monitoring, it cannot accurately reflect the actual working condition of the vibratory compactor by comparing only the rated voltage U and rated current I as reference values. The vibratory compactor still needs to be stopped, which affects work efficiency. Summary of the Invention

[0006] The present invention aims to provide an automatic current limiting and frequency reduction device and method for a vibratory beater. The technical problem to be solved includes how to prevent the vibratory beater from tripping and shutting down due to a sharp rise in current exceeding the upper limit.

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an automatic current limiting and frequency reduction device for a vibratory impactor, comprising a power supply, a data acquisition device, a drive motor, and a frequency converter. The data acquisition device is used to acquire the operating current I of the vibratory impactor in real time. The power supply is used to supply power to the drive motor, which drives the eccentric block inside the vibratory impactor to rotate. The frequency converter is used to control the operating frequency f of the drive motor according to a frequency conversion formula, wherein the frequency conversion formula is:

[0008]

[0009] Where f is the operating frequency of the drive motor; n is the number of pole pairs of the drive motor; μ is the load factor of the drive motor; I is the operating current of the vibratory shock absorber; R is the stator resistance of the drive motor; S is the slip, where n, μ, R, and S are all provided by the manufacturers of the drive motor and the vibratory shock absorber; K is a correction coefficient, set by the user, and 0 < K < 1; F is the rated operating frequency of the drive motor; I 额定 This is the rated operating current of the vibratory impactor.

[0010] Preferably, 0.91 < K < 0.98.

[0011] Preferably, the relationship between the operating frequency f of the drive motor and the rotational speed v of the eccentric block inside the vibratory impactor is determined based on an engineering experience curve.

[0012] Preferably, the relationship between the rotational speed v of the eccentric block inside the vibratory compactor and the excitation force P of the vibratory compactor is calculated using an empirical formula for the excitation force P: calculate;

[0013] Where W is the mass of the eccentric block inside the vibratory impactor; e is the eccentricity of the eccentric block inside the vibratory impactor; and g is the acceleration due to gravity.

[0014] Preferably, the excitation force P of the vibratory impactor is monitored using a combination of direct and indirect monitoring methods. This method involves setting three force-measuring rings at intervals along the axial direction of the vibratory impactor on its outer peripheral wall. Twelve openable force sensors are then installed on the outer peripheral wall of the vibratory impactor via these force-measuring rings. These 12 openable force sensors are divided into three groups, each containing four openable force sensors, symmetrically arranged in a circle along the axial direction of the vibratory impactor. These 12 openable force sensors constitute a direct method for monitoring the excitation force. Additionally, twelve accelerometers installed on the outer peripheral wall of the vibratory impactor via the force-measuring rings constitute an indirect method for monitoring the excitation force. These twelve accelerometers are divided into three groups, each containing four accelerometers, symmetrically arranged on the same force-measuring ring. The positions of the accelerometers and the openable force sensors do not overlap.

[0015] Preferably, both the accelerometer and the opening / closing force sensor are fiber optic sensors.

[0016] Preferably, the opening and closing force sensors of each adjacent ring are evenly arranged in the axial direction of the vibratory impactor.

[0017] Preferably, the adjacent force-measuring rings are spaced 50 cm apart.

[0018] Preferably, a data acquisition device is used to acquire the direct harmonic excitation force FZ output by the direct method monitoring excitation force device and the indirect harmonic excitation force FJ output by the indirect method monitoring excitation force device, wherein,

[0019]

[0020]

[0021] Where T is the average detection time interval between the opening and closing force sensor and the accelerometer, in seconds; x(t) is the curve fitting function formed by the detection output value of the opening and closing force sensor at time t; g(t) is the curve fitting function formed by the detection output value of the accelerometer at time t; and M is the total mass of the vibratory shock device, in kg.

[0022] The direct harmonic excitation force FZ output by the direct method monitoring excitation force device and the indirect harmonic excitation force FJ output by the indirect method monitoring excitation force device are fitted and corrected using a correction coefficient matrix. The specific correction formula is as follows:

[0023]

[0024] Where P is the corrected excitation force of the vibratory compactor; K1 is the principal stiffness coefficient of the vibratory compactor; J is the cross-coupling stiffness coefficient of the vibratory compactor; C is the principal damping coefficient of the vibratory compactor; and A is the cross-damping coefficient of the vibratory compactor. K1, J, C, and A are all provided by the vibratory compactor manufacturer.

[0025] The present invention also provides a current limiting and frequency reducing method for an automatic current limiting and frequency reducing device for a vibratory beater, comprising the following steps:

[0026] Step 1: Real-time acquisition of the operating current I of the vibratory shock absorber;

[0027] The second step is to control the operating frequency f of the drive motor according to the frequency conversion formula, wherein the frequency conversion formula is:

[0028]

[0029] Where f is the operating frequency of the drive motor; n is the number of pole pairs of the drive motor; μ is the load factor of the drive motor; I is the operating current of the vibratory shock absorber; R is the stator resistance of the drive motor; S is the slip, where n, μ, R, and S are all provided by the manufacturers of the drive motor and the vibratory shock absorber; K is a correction coefficient, set by the user, and 0 < K < 1; F is the rated operating frequency of the drive motor; I 额定 This is the rated operating current of the vibratory impactor.

[0030] Beneficial effects

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] The automatic current limiting and frequency reduction device for vibratory impactors described in this invention controls the operating frequency f of the drive motor through a frequency conversion formula, thus completely avoiding the problem of the vibratory impactor tripping and shutting down due to a sharp increase in current exceeding the upper limit.

[0033] The aforementioned frequency conversion formula was obtained by fitting a function between the operating frequency f of the drive motor and the corresponding operating current I of the vibratory shock in the sample space using the SageMath open-source mathematical software system. The fitted functional relationship was then tested using the operating frequency f of the drive motor and the corresponding operating current I of the vibratory shock in the test space. Different performance parameters of the drive motor and the vibratory shock were introduced as coefficients during the function fitting process until the test results achieved the desired degree of agreement. Ultimately, it was found that the frequency conversion formula using the number of pole pairs n of the drive motor, the load factor μ of the drive motor, the stator resistance R of the drive motor, and the slip S as coefficients yielded the optimal agreement.

[0034] At the same time, to avoid the operating current I of the vibrator being too close to the rated operating current I of the vibrator. 额定The introduction of a correction factor K, which could lead to the burnout or shutdown of the vibratory compactor, makes its operation safer. Attached Figure Description

[0035] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the specific embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0036] Figure 1 This is a schematic diagram of the structural logic of the automatic current limiting and frequency reduction device for the vibratory impactor described in this invention.

[0037] Figure 2 This is a schematic diagram showing the relationship between the operating frequency f of the drive motor and the rotational speed v of the eccentric block inside the vibratory impactor as described in this invention. Detailed Implementation

[0038] The invention is described in more detail below to aid in understanding it.

[0039] like Figure 1 As shown, the automatic current limiting and frequency reduction device for the vibratory impactor of the present invention includes a power supply, a data acquisition device, a drive motor, and a frequency converter. The data acquisition device is used to acquire the operating current I of the vibratory impactor in real time. The power supply is used to supply power to the drive motor, and the drive motor is used to drive the eccentric block inside the vibratory impactor to rotate. The frequency converter is used to control the operating frequency f of the drive motor according to the frequency conversion formula, wherein the frequency conversion formula is:

[0040]

[0041] Where f is the operating frequency of the drive motor; n is the number of pole pairs of the drive motor; μ is the load factor of the drive motor; I is the operating current of the vibratory shock absorber; R is the stator resistance of the drive motor; S is the slip, where n, μ, R, and S are all provided by the manufacturers of the drive motor and the vibratory shock absorber; K is a correction coefficient, set by the user, and 0 < K < 1; F is the rated operating frequency of the drive motor; I 额定 This is the rated operating current of the vibratory impactor.

[0042] Preferably, 0.91 < K < 0.98.

[0043] The operating frequency f of the drive motor directly affects the rotational speed v of the eccentric block inside the vibratory compactor, which in turn directly affects the excitation force P of the vibratory compactor. The excitation force P can be calculated using the empirical formula:

[0044] Where W is the mass of the eccentric block inside the vibratory impactor; e is the eccentricity of the eccentric block inside the vibratory impactor; and g is the acceleration due to gravity.

[0045] The relationship between the operating frequency f of the drive motor and the rotational speed v of the eccentric block inside the vibratory impactor can be determined based on empirical curves (such as...). Figure 1 As shown in the figure, confirm.

[0046] The excitation force P of the vibratory compactor can be monitored using direct and / or indirect monitoring methods. Direct monitoring involves constructing a support structure at the front end of the vibratory compactor, within which a force sensor is embedded to directly measure the excitation force. Indirect monitoring calculates the excitation force by measuring the vibration response and system dynamic characteristics.

[0047] The applicant also proposed a monitoring method combining direct and indirect monitoring. This method involves setting three force-measuring rings at intervals along the axial direction of the vibratory impactor on its outer peripheral wall. Twelve opening and closing force sensors are then installed on the outer peripheral wall of the vibratory impactor via these force-measuring rings. These 12 force sensors are divided into three groups, each containing four sensors, symmetrically arranged in a circle along the axial direction of the vibratory impactor. These 12 force sensors constitute a direct method for monitoring the excitation force. Twelve accelerometers, also located on the outer peripheral wall of the vibratory impactor via the force-measuring rings, constitute an indirect method for monitoring the excitation force. These 12 accelerometers are divided into three groups, each containing four accelerometers, symmetrically arranged on the same force-measuring ring. The positions of the accelerometers and the opening and closing force sensors do not overlap. Both the accelerometers and the opening and closing force sensors utilize fiber optic sensors. The opening and closing force sensors of each adjacent ring are evenly arranged along the axial direction of the vibratory shock absorber (e.g., spaced 50 cm apart). The force measuring rings are spaced 50 cm apart.

[0048] In both the direct and indirect monitoring methods, fiber optic sensors are used. To provide stability and maintainability of the line, and to reduce production and maintenance costs, this invention adopts a series-parallel combination scheme.

[0049] Specifically, the opening and closing force sensors on the same force measuring ring are connected in series, the accelerometers on the same force measuring ring are connected in series, the opening and closing force sensors on different force measuring rings are connected in parallel, and the accelerometers on different force measuring rings are connected in parallel.

[0050] The accelerometer detects a current signal of 4mA to 20mA, or a voltage signal of 0V to 10V. The acquired signals are processed and converted using a known acquisition device in the prior art, and the force is calculated using Newton's second law.

[0051] The direct harmonic excitation force FZ output by the direct method monitoring excitation force device and the indirect harmonic excitation force FJ output by the indirect method monitoring excitation force device are acquired using existing data acquisition devices.

[0052]

[0053]

[0054] Where T is the average detection time interval between the opening and closing force sensor and the accelerometer, in seconds; x(t) is the curve fitting function formed by the detection output value of the opening and closing force sensor at time t; g(t) is the curve fitting function formed by the detection output value of the accelerometer at time t; and M is the total mass of the vibrator, in kg.

[0055] The connecting wires of the accelerometer and the connecting wires of the opening / closing force sensor are electrically connected to the data acquisition unit, enabling the data acquisition unit to collect the direct harmonic excitation force FZ output by the direct method monitoring excitation force device and the indirect harmonic excitation force FJ output by the indirect method monitoring excitation force device. The data acquisition unit has a built-in controller, which allows the user to set the average detection time interval T of the opening / closing force sensor and the accelerometer, as well as the total mass M of the vibratory shock device. The controller can automatically divide the average detection time interval T into predetermined time periods and, based on the detection values ​​at the midpoint of each time period, fit curve fitting functions formed by the detection output values ​​of the opening / closing force sensor and the accelerometer.

[0056] The direct harmonic excitation force FZ output by the direct method monitoring excitation force device and the indirect harmonic excitation force FJ output by the indirect method monitoring excitation force device are fitted and corrected using a correction coefficient matrix. The specific correction formula is as follows:

[0057]

[0058] Where P is the corrected excitation force of the vibratory compactor; K1 is the principal stiffness coefficient of the vibratory compactor; J is the cross-coupling stiffness coefficient of the vibratory compactor; C is the principal damping coefficient of the vibratory compactor; and A is the cross-damping coefficient of the vibratory compactor. K1, J, C, and A are all provided by the vibratory compactor manufacturer.

[0059] A first correction matrix is ​​formed by the principal stiffness coefficient K1 and the cross-coupling stiffness coefficient J of the vibratory impactor, and a second correction matrix is ​​formed by the principal damping coefficient C and the cross-damping coefficient A of the vibratory impactor. The first and second correction matrices are then used to construct a correction formula. The corrected excitation force of the vibratory impactor obtained by this formula differs from the baseline value obtained under corresponding laboratory conditions by a maximum difference of only 1.4% and a minimum difference of only 0.2%. Therefore, the applicant believes that the monitoring results obtained using this correction formula are basically consistent with the baseline value obtained under laboratory conditions, and can greatly improve the accuracy of the monitoring data compared with the monitoring results obtained by simply using the direct method or the indirect method to monitor the excitation force device.

[0060] To determine how to control the operating frequency f of the drive motor, the applicant conducted numerous experiments. During the experiments, the excitation force P and operating current I of the vibratory impactor were detected according to the method described above. The maximum value of the excitation force P corresponding to the operating current I of the same vibratory impactor was found. The rotational speed v of the eccentric block inside the vibratory impactor corresponding to the maximum value of the excitation force P was calculated. Then, based on engineering experience curves (such as...), the results were determined. Figure 1 (As shown) Determine the operating frequency f of the drive motor corresponding to the rotational speed v of the eccentric block inside the vibratory impactor. Varying the operating current I yields a set of different drive motor operating frequencies f. Changing the vibratory impactor yields different sets of drive motor operating frequencies f. Divide the obtained drive motor operating frequency f data into a sample space and a test space.

[0061] By using the operating frequency f of the drive motor and the corresponding operating current I of the vibratory shock in the sample space, a function fitting was performed (using the SageMath open-source mathematical software system) to obtain different function curves and functional relationships. Then, the fitted functional relationships were tested using the operating frequency f of the drive motor and the corresponding operating current I of the vibratory shock in the test space. Different performance parameters of the drive motor and vibratory shock were introduced as coefficients during the function fitting process until the test results achieved the desired degree of agreement. Finally, it was found that the frequency conversion formula using the number of pole pairs n of the drive motor, the load coefficient μ of the drive motor, the stator resistance R of the drive motor, and the slip S of the drive motor as coefficients yielded the optimal agreement result.

[0062] At the same time, to avoid the operating current I of the vibrator being too close to the rated operating current I of the vibrator. 额定 The introduction of a correction factor K, which could lead to the burnout or shutdown of the vibratory compactor, makes its operation safer.

[0063] The preferred embodiments of the present invention have been described above, but are not intended to limit the invention. Those skilled in the art can make modifications and variations to the embodiments disclosed herein without departing from the scope and spirit of the invention.

Claims

1. An automatic current limiting and frequency reduction device for a vibratory beater, characterized in that, The automatic current limiting and frequency reduction device for the vibratory impactor includes a power supply, a data acquisition device, a drive motor, and a frequency converter. The data acquisition device is used to acquire the operating current I of the vibratory impactor in real time. The power supply is used to supply power to the drive motor, and the drive motor is used to drive the eccentric block inside the vibratory impactor to rotate. The frequency converter is used to control the operating frequency f of the drive motor according to a frequency conversion formula, wherein the frequency conversion formula is: Where f is the operating frequency of the drive motor; n is the number of pole pairs of the drive motor; μ is the load factor of the drive motor; I is the operating current of the vibratory shock absorber; R is the stator resistance of the drive motor; S is the slip, where n, μ, R, and S are all provided by the manufacturers of the drive motor and the vibratory shock absorber; K is a correction coefficient, set by the user, and 0 < K < 1; F is the rated operating frequency of the drive motor; I 额定 This is the rated operating current of the vibratory impactor.

2. The automatic current limiting and frequency reduction device for the vibratory beater according to claim 1, characterized in that, 0.91＜K＜0.98。 3. The automatic current limiting and frequency reduction device for the vibratory beater according to claim 1, characterized in that, The relationship between the operating frequency f of the drive motor and the rotational speed v of the eccentric block inside the vibratory impactor is determined based on an engineering experience curve.

4. The automatic current limiting and frequency reduction device for vibratory beaters according to claim 1, characterized in that, The relationship between the rotational speed v of the eccentric block inside the vibratory compactor and the excitation force P of the vibratory compactor is calculated using an empirical formula for the excitation force P: calculate; Where W is the mass of the eccentric block inside the vibratory impactor; e is the eccentricity of the eccentric block inside the vibratory impactor; and g is the acceleration due to gravity.

5. The automatic current limiting and frequency reduction device for the vibratory beater according to claim 1, characterized in that, The excitation force P of the vibratory impactor is monitored using a combination of direct and indirect monitoring methods. This method involves setting three force-measuring rings at intervals along the axial direction of the vibratory impactor on its outer peripheral wall. Twelve openable force sensors are then installed on the outer peripheral wall of the vibratory impactor via these force-measuring rings. These 12 openable force sensors are divided into three groups, each containing four openable force sensors, symmetrically arranged in a circle along the axial direction of the vibratory impactor. These 12 openable force sensors constitute a direct method for monitoring the excitation force. Additionally, twelve accelerometers installed on the outer peripheral wall of the vibratory impactor via the force-measuring rings constitute an indirect method for monitoring the excitation force. These twelve accelerometers are divided into three groups, each containing four accelerometers, symmetrically arranged on the same force-measuring ring. The positions of the accelerometers and the openable force sensors do not overlap.

6. The automatic current limiting and frequency reduction device for the vibratory beater according to claim 5, characterized in that, Both the accelerometer and the opening / closing force sensor mentioned above use fiber optic sensors.

7. The automatic current limiting and frequency reduction device for vibratory beaters according to claim 5, characterized in that, The opening and closing force sensors of each adjacent ring are evenly arranged in the axial direction of the vibratory impactor.

8. The automatic current limiting and frequency reduction device for the vibratory beater according to claim 5, characterized in that, The adjacent force measuring rings are spaced 50cm apart.

9. The automatic current limiting and frequency reduction device for the vibratory beater according to claim 5, characterized in that, The direct harmonic excitation force FZ output by the direct method monitoring excitation force device and the indirect harmonic excitation force FJ output by the indirect method monitoring excitation force device are collected using a data acquisition device. ； ； Where T is the average detection time interval between the opening and closing force sensor and the accelerometer, in seconds; x(t) is the curve fitting function formed by the detection output value of the opening and closing force sensor at time t; g(t) is the curve fitting function formed by the detection output value of the accelerometer at time t; and M is the total mass of the vibratory shock device, in kg. The direct harmonic excitation force FZ output by the direct method monitoring excitation force device and the indirect harmonic excitation force FJ output by the indirect method monitoring excitation force device are fitted and corrected using a correction coefficient matrix. The specific correction formula is as follows: ； Wherein, P1 is the corrected excitation force of the vibratory impactor; K1 is the principal stiffness coefficient of the vibratory impactor; J is the cross-coupling stiffness coefficient of the vibratory impactor; C is the principal damping coefficient of the vibratory impactor; and A is the cross-damping coefficient of the vibratory impactor. K1, J, C, and A are all provided by the vibratory impactor manufacturer.

10. A current limiting and frequency reducing method for an automatic current limiting and frequency reducing device for a vibratory beater according to any one of claims 1 to 9, characterized in that, Includes the following steps: Step 1: Real-time acquisition of the operating current I of the vibratory shock absorber; The second step is to control the operating frequency f of the drive motor according to the frequency conversion formula, wherein the frequency conversion formula is: Where f is the operating frequency of the drive motor; n is the number of pole pairs of the drive motor; μ is the load factor of the drive motor; I is the operating current of the vibratory shock absorber; R is the stator resistance of the drive motor; S is the slip, where n, μ, R, and S are all provided by the manufacturers of the drive motor and the vibratory shock absorber; K is a correction coefficient, set by the user, and 0 < K < 1; F is the rated operating frequency of the drive motor; I 额定 This is the rated operating current of the vibratory impactor.

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