An embedded integrated control system for the luffing mechanism of a tower crane

Abstract

This invention relates to an embedded integrated control system for the luffing mechanism of a tower crane. Vibration detectors and stress detectors are installed within the luffing mechanism to monitor the luffing process in real time. The luffing controller connects to a calculation module, a luffing motor, a force detector, and a vibration detector. The luffing motor sends data collected by the power detector, force detector, and vibration detector to the calculation module. The calculation module inputs the data into a computational model to obtain the stability coefficient of the running trolley. This provides more comprehensive monitoring factors, higher monitoring stability, and better accuracy. The vibration sensors are divided into three types to detect vibrations in three directions, resulting in more accurate detection. The calculation fully considers the influence of vibration amplitudes in different directions, multiplying the vibration amounts in different directions by corresponding coefficients, leading to more accurate detection and more stable calculation results.

Description

Technical Field

[0001] This invention relates to the field of crane control, and more particularly to an embedded integrated control system for the luffing mechanism of a tower crane. Background Technology

[0002] The luffing mechanism is the main working mechanism of a boom crane. It is used to change the crane's amplitude, that is, to change the horizontal distance from the center of the hook (or grab) to the crane's rotation center axis, so as to adapt the crane to loading and unloading goods under different conditions.

[0003] Application number CN201511002585.1 discloses a frequency conversion speed control system and control method for a tower crane luffing mechanism. The control system includes a linkage console, a limit signal acquisition device, a PLC controller, and a frequency converter. The limit signal acquisition device and the frequency converter are respectively connected to the PLC controller. The frequency converter is respectively connected to the linkage console and the luffing motor of the luffing mechanism. The linkage console, the frequency converter, the luffing motor of the luffing mechanism, the reducer, and the drum constitute a sequential control loop.

[0004] Application number CN201721128817.2 discloses a luffing mechanism using a frequency converter for use in a tower crane. It includes a slewing luffing control console, a slewing mechanism electrically connected to the slewing luffing control console, a hoisting mechanism electrically connected to the slewing luffing control console, and a distribution box electrically connected to the slewing luffing control console, the slewing motor, and the hoisting motor, respectively. Both the slewing mechanism and the hoisting mechanism are equipped with frequency converters that use open-loop vector control for the slewing mechanism and the hoisting mechanism, and both the slewing mechanism and the hoisting mechanism are equipped with squirrel-cage frequency converter motors.

[0005] None of the above methods can achieve real-time data detection and real-time smooth control during variable amplitude motion. Summary of the Invention

[0006] To address the above issues, an embedded integrated control system for the luffing mechanism of a tower crane is provided, comprising a luffing controller, a calculation module, a luffing motor, a force detector, and a vibration detector.

[0007] The luffing motor is connected to the traveling trolley, which drives the traveling trolley to move back and forth along the extension direction of the boom to achieve luffing. The luffing motor is equipped with a power detector, which is connected to the luffing controller and sends the operating power P of the luffing motor to the luffing controller.

[0008] The force detection module includes multiple strain sensors, which are installed on the middle arm to detect the strain generated by the force on the crane arm during the movement of the trolley, and send the strain to the luffing controller.

[0009] The vibration detection module includes a vibration sensor, which is installed on the moving trolley. The vibration sensor detects the vibration of the moving trolley during its movement and sends the vibration waveform to the amplitude controller.

[0010] The luffing controller is also connected to a calculation module, a luffing motor, a force detector, and a vibration detector. The luffing motor sends the data collected by the power detector, the force detector, and the vibration detector to the calculation module. The calculation module inputs the data into the calculation model to obtain the stability coefficient of the running trolley.

[0011] The luffing controller controls the luffing motor based on the stability coefficient, which in turn controls the running speed of the trolley.

[0012] The lifting boom is a horizontal lifting boom, and the traveling trolley moves back and forth along the lifting boom under the drive of the luffing motor; multiple strain sensors are set along the extension direction of the lifting boom, and the spacing between them is equal.

[0013] Each strain sensor sends a detected strain value to the amplitude controller in real time during operation, thus the amplitude controller obtains a set of strain values ​​a1, a2, ..., a in real time. n ;

[0014] The strain sensor is a grating fiber optic strain sensor.

[0015] The vibration detection module includes vibration sensors, which are installed on the running trolley. These sensors include X-direction vibration sensors, Y-direction vibration sensors, and Z-direction vibration sensors. The vibration sensors are acceleration-type vibration sensors. The three vibration sensors send their own acceleration data to the vibration detection module in real time. The vibration detection module plots the acceleration data of the three vibration sensors into curves that change over time and sends the three curves to the amplitude transformer controller in real time.

[0016] The X direction is the horizontal direction along the extension of the crane boom; the Y direction is perpendicular to the X direction and parallel to the horizontal direction; the Z direction is the vertical direction.

[0017] The vibration detection module sends three curves to the amplitude controller in real time: Sx(t), Sy(t), and Sz(t). Among them, Sx(t) is the change of acceleration of the vibration sensor in the X direction with time, Sy(t) is the change of acceleration of the vibration sensor in the Y direction with time, and Sz(t) is the change of acceleration of the vibration sensor in the Z direction with time.

[0018] The range of t is 0-5s, meaning that the vibration detector only sends data that is 5 seconds back from the current moment.

[0019] The calculation module calculates the operating power P and the strain a1, a2, ..., a of the variable amplitude motor. nThe specific method for processing and calculating the curves Sx(t), Sy(t), and Sz(t), and then inputting them into the computational model to obtain the stationarity coefficient β is as follows:

[0020] The calculation module calculates the dependent variables a1, a2, ..., a n Subtracting the strain of each of the trolleys when they are unloaded yields a'1, a'2, ..., a' n , and from a'1, a'2,...,a' n The strain variables greater than the threshold M are selected, and then the strain sensor farthest from the root of the crane boom is selected from the strain sensors corresponding to the strain variables greater than the threshold; the distance L between the farthest strain sensor and the root of the crane is obtained.

[0021] The calculation module calculates the total strain of all strain sensors, i.e., it calculates a'1, a'2, ..., a' n and A;

[0022] The calculation module obtains the maximum values ​​Gx, Gy, and Gz of Sx(t), Sy(t), and Sz(t); at the same time, it converts Sx(t), Sy(t), and Sz(t) into the frequency domain to obtain the corresponding spectra of Sx(t), Sy(t), and Sz(t), and calculates their respective strongest frequencies Fx, Fy, and Fz from the corresponding spectra of Sx(t), Sy(t), and Sz(t);

[0023] Stationarity coefficient β:

[0024]

[0025] Where L0 is the total length of the boom, P0 is the rated power of the luffing motor, F0 is the resonant frequency of the trolley, and k, r1, and r2 are coefficients of the balance dimension.

[0026] The amplitude controller controls the amplitude motor based on the stability coefficient β, and further controls the running speed of the trolley to ensure that the running speed v ≤ k2·β, where k2 is a coefficient set based on experience.

[0027] The present invention sets up vibration detectors and stress detectors in the luffing mechanism to monitor the luffing process in real time. The luffing controller is connected to the calculation module, the luffing motor, the force detector and the vibration detector. The luffing motor sends the data collected by the power detector, the force detector and the vibration detector to the calculation module. The calculation module inputs the data into the calculation model to obtain the stability coefficient of the running trolley.

[0028] The power detector characterizes the working pressure of the luffing motor, the stress detector characterizes the force on the luffing mechanism during operation, and the vibration detector characterizes the motion stability of the luffing mechanism during operation. The data detected by the three detection devices are combined and calculated to obtain the operational stability of the luffing mechanism. The monitoring factors are more comprehensive, the monitoring stability is higher, and the accuracy is better.

[0029] The vibration sensors are divided into three types to detect vibrations in three directions, which makes the detection more accurate. The calculation fully considers the influence of vibration amplitude in different directions, and multiplies the vibration amount in different directions by the corresponding coefficient, which makes the detection more accurate and the calculation results more stable. Attached Figure Description

[0030] The accompanying drawings, included to provide a further understanding of the disclosed subject matter, are incorporated into and form part of this specification. The drawings also illustrate the implementation of the disclosed subject matter, and, together with the detailed description, serve to explain the principles of its implementation. No attempt is made to demonstrate excessive structural detail to provide a basic understanding of the disclosed subject matter and its various practical applications.

[0031] Figure 1 This is a schematic diagram of the overall architecture of the present invention.

[0032] Figure 2 This is a schematic diagram of a partial structure of the tower crane. Detailed Implementation

[0033] The advantages, features, and methods of achieving the stated objectives of this invention will become clear from the accompanying drawings and the following detailed description.

[0034] Example 1:

[0035] Combination Figure 1-2 An embedded integrated control system for the luffing mechanism of a tower crane includes a luffing controller, a computing module, a luffing motor, a force detector, and a vibration detector.

[0036] The luffing motor is connected to the traveling trolley, which drives the traveling trolley to move back and forth along the extension direction of the boom to achieve luffing. The luffing motor is equipped with a power detector, which is connected to the luffing controller and sends the operating power P of the luffing motor to the luffing controller.

[0037] The force detection module includes multiple strain sensors, which are installed on the middle arm to detect the strain generated by the force on the crane arm during the movement of the trolley, and send the strain to the luffing controller.

[0038] The vibration detection module includes a vibration sensor, which is installed on the moving trolley. The vibration sensor detects the vibration of the moving trolley during its movement and sends the vibration waveform to the amplitude controller.

[0039] The luffing controller is also connected to a calculation module, a luffing motor, a force detector, and a vibration detector. The luffing motor sends the data collected by the power detector, the force detector, and the vibration detector to the calculation module. The calculation module inputs the data into the calculation model to obtain the stability coefficient of the running trolley.

[0040] The luffing controller controls the luffing motor based on the stability coefficient, which in turn controls the running speed of the trolley.

[0041] The lifting boom is a horizontal lifting boom, and the traveling trolley moves back and forth along the lifting boom under the drive of the luffing motor; multiple strain sensors are set along the extension direction of the lifting boom, and the spacing between them is equal.

[0042] Each strain sensor sends a detected strain value to the amplitude controller in real time during operation, thus the amplitude controller obtains a set of strain values ​​a1, a2, ..., a in real time. n ;

[0043] The strain sensor is a grating fiber optic strain sensor.

[0044] The vibration detection module includes vibration sensors, which are installed on the running trolley. These sensors include X-direction vibration sensors, Y-direction vibration sensors, and Z-direction vibration sensors. The vibration sensors are acceleration-type vibration sensors. The three vibration sensors send their own acceleration data to the vibration detection module in real time. The vibration detection module plots the acceleration data of the three vibration sensors into curves that change over time and sends the three curves to the amplitude transformer controller in real time.

[0045] The X direction is the horizontal direction along the extension of the crane boom; the Y direction is perpendicular to the X direction and parallel to the horizontal direction; the Z direction is the vertical direction.

[0046] The vibration detection module sends three curves to the amplitude controller in real time: Sx(t), Sy(t), and Sz(t). Among them, Sx(t) is the change of acceleration of the vibration sensor in the X direction with time, Sy(t) is the change of acceleration of the vibration sensor in the Y direction with time, and Sz(t) is the change of acceleration of the vibration sensor in the Z direction with time.

[0047] The range of t is 0-5s, meaning that the vibration detector only sends data that is 5 seconds back from the current moment.

[0048] The calculation module calculates the operating power P and the strain a1, a2, ..., a of the variable amplitude motor. nThe specific method for processing and calculating the curves Sx(t), Sy(t), and Sz(t), and then inputting them into the computational model to obtain the stationarity coefficient β is as follows:

[0049] The calculation module calculates the dependent variables a1, a2, ..., a n Subtracting the strain of each of the trolleys when they are unloaded yields a'1, a'2, ..., a' n , and from a'1, a'2,...,a' n The strain variables greater than the threshold M are selected, and then the strain sensor farthest from the root of the crane boom is selected from the strain sensors corresponding to the strain variables greater than the threshold; the distance L between the farthest strain sensor and the root of the crane is obtained.

[0050] The calculation module calculates the total strain of all strain sensors, i.e., it calculates a'1, a'2, ..., a' n and A;

[0051] The calculation module obtains the maximum values ​​Gx, Gy, and Gz of Sx(t), Sy(t), and Sz(t); at the same time, it converts Sx(t), Sy(t), and Sz(t) into the frequency domain to obtain the corresponding spectra of Sx(t), Sy(t), and Sz(t), and calculates their respective strongest frequencies Fx, Fy, and Fz from the corresponding spectra of Sx(t), Sy(t), and Sz(t);

[0052] Stationarity coefficient β:

[0053]

[0054] Where L0 is the total length of the boom, P0 is the rated power of the luffing motor, F0 is the resonant frequency of the trolley, and k, r1, and r2 are coefficients of the balance dimension.

[0055] The amplitude controller controls the amplitude motor based on the stability coefficient β, and further controls the running speed of the trolley to ensure that the running speed v ≤ k2·β, where k2 is a coefficient set based on experience.

[0056] Example 2:

[0057] This embodiment further explains the working method of the amplitude control system.

[0058] With the tower crane unloaded and the trolley stationary at the base of the boom, each strain sensor sends a detected strain value to the luffing controller in real time, and the luffing controller obtains a set of unloaded strain values ​​in real time.

[0059] The tower crane starts loading goods and begins operation. The trolley moves the goods back and forth along the extension direction of the boom to achieve luffing. The power detector sends the operating power P of the luffing motor to the luffing controller; the strain sensor sends the strain to the luffing controller; and the vibration sensor sends the vibration waveform to the luffing controller.

[0060] Each strain sensor sends a detected strain value to the amplitude controller in real time during operation, thus the amplitude controller obtains a set of strain values ​​a1, a2, ..., a in real time. n The vibration detection module sends three curves to the amplitude controller in real time: Sx(t), Sy(t), and Sz(t). Among them, Sx(t) is the change of acceleration of the vibration sensor in the X direction with time, Sy(t) is the change of acceleration of the vibration sensor in the Y direction with time, and Sz(t) is the change of acceleration of the vibration sensor in the Z direction with time.

[0061] The range of t is 0-5s, meaning that the vibration detector only sends data that is 5 seconds back from the current moment.

[0062] The calculation module calculates the dependent variables a1, a2, ..., a n Subtracting the strain of each of the trolleys when they are unloaded yields a'1, a'2, ..., a' n , and from a'1, a'2,...,a' n The strain variables greater than the threshold M are selected, and then the strain sensor farthest from the root of the crane boom is selected from the strain sensors corresponding to the strain variables greater than the threshold; the distance L between the farthest strain sensor and the root of the crane is obtained.

[0063] The calculation module calculates the total strain of all strain sensors, i.e., it calculates a'1, a'2, ..., a' n and A;

[0064] The calculation module obtains the maximum values ​​Gx, Gy, and Gz of Sx(t), Sy(t), and Sz(t); at the same time, it converts Sx(t), Sy(t), and Sz(t) into the frequency domain to obtain the corresponding spectra of Sx(t), Sy(t), and Sz(t), and calculates their respective strongest frequencies Fx, Fy, and Fz from the corresponding spectra of Sx(t), Sy(t), and Sz(t);

[0065] Stationarity coefficient β:

[0066]

[0067] Where L0 is the total length of the boom, P0 is the rated power of the luffing motor, F0 is the resonant frequency of the trolley, and k, r1, and r2 are coefficients of the balance dimension.

[0068] The amplitude controller controls the amplitude motor based on the stability coefficient β, and further controls the running speed of the trolley to ensure that the running speed v ≤ k2·β, where k2 is a coefficient set based on experience.

[0069] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An embedded integrated control system for the luffing mechanism of a tower crane, comprising a luffing controller, a calculation module, a luffing motor, a force detector, and a vibration detector; characterized in that: The luffing motor is connected to the traveling trolley, which drives the traveling trolley to move back and forth along the extension direction of the boom to achieve luffing. The luffing motor is equipped with a power detector, which is connected to the luffing controller and sends the operating power P of the luffing motor to the luffing controller. The force detection module includes multiple strain sensors, which are installed on the boom to detect the strain generated by the force on the boom during the movement of the trolley, and send the strain to the luffing controller. The vibration detection module includes a vibration sensor, which is installed on the moving trolley. The vibration sensor detects the vibration of the moving trolley during its movement and sends the vibration waveform to the amplitude controller. The luffing controller is also connected to a calculation module, a luffing motor, a force detector, and a vibration detector. The luffing motor sends the data collected by the power detector, the force detector, and the vibration detector to the calculation module. The calculation module inputs the data into the calculation model to obtain the stability coefficient of the running trolley. The luffing controller controls the luffing motor based on the stability coefficient, which in turn controls the running speed of the trolley. The lifting boom is a horizontal lifting boom, and the traveling trolley moves back and forth along the lifting boom under the drive of the luffing motor; Multiple strain sensors are installed along the extension direction of the crane boom, with equal spacing between them; Each strain sensor sends a detected strain value to the amplitude controller in real time during operation, thus the amplitude controller obtains a set of strain values ​​a1, a2, ..., a in real time. n ; The vibration detection module includes vibration sensors, which are installed on the running trolley. These sensors include X-direction vibration sensors, Y-direction vibration sensors, and Z-direction vibration sensors. The vibration sensors are acceleration-type vibration sensors. The three vibration sensors send their own acceleration data to the vibration detection module in real time. The vibration detection module plots the acceleration data of the three vibration sensors into curves that change over time and sends the three curves to the amplitude transformer controller in real time. The X direction is the horizontal direction along the extension of the crane boom; the Y direction is perpendicular to the X direction and parallel to the horizontal direction; the Z direction is the vertical direction. The vibration detection module sends three curves to the amplitude controller in real time: Sx(t), Sy(t), and Sz(t). Among them, Sx(t) is the change of acceleration of the vibration sensor in the X direction with time, Sy(t) is the change of acceleration of the vibration sensor in the Y direction with time, and Sz(t) is the change of acceleration of the vibration sensor in the Z direction with time. The range of t is 0-5s, meaning that the vibration detector only sends data that is 5 seconds backward from the current time. The calculation module calculates the operating power P and the strain a1, a2, ..., a of the variable amplitude motor. n The specific method for processing and calculating the curves Sx(t), Sy(t), and Sz(t), and then inputting them into the computational model to obtain the stationarity coefficient β is as follows: The calculation module calculates the dependent variables a1, a2, ..., a n Subtracting the strain of each of the trolleys when they are unloaded yields a'1, a'2, ..., a' n , and from a'1, a'2,...,a' n The strain variables greater than the threshold M are selected, and then the strain sensor farthest from the root of the crane boom is selected from the strain sensors corresponding to the strain variables greater than the threshold; the distance L between the farthest strain sensor and the root of the crane is obtained. The calculation module calculates the total strain of all strain sensors, i.e., it calculates a'1, a'2, ..., a' n and A; The calculation module obtains the maximum values ​​Gx, Gy, and Gz of Sx(t), Sy(t), and Sz(t); at the same time, it converts Sx(t), Sy(t), and Sz(t) into the frequency domain to obtain the corresponding spectra of Sx(t), Sy(t), and Sz(t), and calculates their respective strongest frequencies Fx, Fy, and Fz from the corresponding spectra of Sx(t), Sy(t), and Sz(t); Stationarity coefficient β: Where L0 is the total length of the boom, P0 is the rated power of the luffing motor, F0 is the resonant frequency of the trolley, and k, r1, and r2 are coefficients of the balance dimension. The amplitude controller controls the amplitude motor based on the stability coefficient β, and further controls the running speed of the trolley to ensure that the running speed v ≤ k2·β, where k2 is a coefficient set based on experience.

2. The embedded integrated control system for the luffing mechanism of a tower crane according to claim 1, characterized in that: The strain sensor is a grating fiber optic strain sensor.

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