Control methods, devices, controllers, tower cranes, and storage media for tower cranes.

Abstract

This application provides a control method, device, controller, tower crane, and storage medium for tower cranes. The method includes: acquiring the drive current of the tower crane's motor in each sampling period; determining whether a first difference between the drive current in the current sampling period and the drive current in the previous sampling period is within a first preset range; and executing a first preset countermeasure if the first difference is not within the first preset range. Through this technical solution, rapid identification and automatic protection against sudden working conditions such as hoisting anchorage or sudden load changes are achieved, ensuring the reliable, safe, and efficient operation of the tower crane.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, specifically to a control method, device, controller, tower crane, and storage medium for tower cranes. Background Technology

[0002] Tower cranes, also known as tower hoists, are widely used material handling machinery on construction sites. When performing lifting operations, tower cranes control the up-and-down movement of the hook, the forward-and-backward movement of the luffing trolley, and the slewing motion, enabling them to lift items from any location within the boom's length.

[0003] Existing tower cranes generally use lifting weight sensors to detect lifting weight signals, which are then transmitted to a PLC (Programmable Logic Controller) via analog or digital communication methods. When the PLC detects an abnormality in the lifting weight signal, it sends control commands to the frequency converter to control the motor. However, in this control method, the data transmission link is too long. When the tower crane experiences sudden situations such as hoisting anchorage or sudden load changes, the time window for taking preventative measures is usually only a few hundred milliseconds or even tens of milliseconds. The existing control method cannot quickly detect and take timely preventative measures for sudden situations such as hoisting anchorage or sudden load changes, which may cause great damage to the tower crane. Summary of the Invention

[0004] The purpose of this application is to provide a control method, device, controller, tower crane, and storage medium for tower cranes.

[0005] To achieve the above objectives, the first aspect of this application provides a control method for a tower crane, comprising:

[0006] Obtain the drive current of the tower crane's motor for each sampling period;

[0007] Determine whether the first difference between the drive current of the current sampling period and the drive current of the previous sampling period is within a first preset range;

[0008] If it is determined that the first difference is not within the first preset range, the first preset response measure shall be executed.

[0009] In this embodiment of the application, the control method further includes:

[0010] Obtain the motor speed for each sampling period;

[0011] The target drive current of the motor is determined for each sampling period based on the rotational speed and the target rotational speed of the motor.

[0012] Determine whether the second difference between the target drive current in the current sampling period and the target drive current in the previous sampling period is within a second preset range;

[0013] If it is determined that the second difference is not within the second preset range, the second preset response measures shall be implemented.

[0014] In this embodiment of the application, determining the target drive current of the motor for each sampling period based on the rotational speed and the target rotational speed of the motor includes:

[0015] The difference between the rotational speed and the target rotational speed of the motor is used to perform PID calculations to obtain the target drive current of the motor for each sampling period.

[0016] In this embodiment of the application, the control method further includes:

[0017] The target rotor angle of the motor is determined for each sampling cycle based on the rotational speed and the target drive current.

[0018] The predicted drive current of the motor for each sampling period is determined based on the drive current and the target rotor angle.

[0019] Determine whether the third difference between the predicted drive current of the current sampling period and the predicted drive current of the previous sampling period is within a third preset range.

[0020] If it is determined that the third difference is not within the third preset range, the third preset response measures shall be implemented.

[0021] In this embodiment of the application, the motor is an asynchronous motor;

[0022] The target rotor angle of the motor for each sampling period is determined based on the rotational speed and the target drive current, including:

[0023] The slip of the asynchronous motor for each sampling period is determined based on the target drive current;

[0024] The target rotor angle of the asynchronous motor for each sampling period is determined based on the rotational speed and slip.

[0025] In this embodiment of the application, determining the slip of the asynchronous motor for each sampling period based on the target drive current includes:

[0026] The slip of the asynchronous motor for each sampling period is determined according to formula (1):

[0027]

[0028] Where, ω sl τ represents the slip of the asynchronous motor for each sampling period. r The rotor time constant of the asynchronous motor is represented by s, where s represents the differential operator. The q-axis component of the target drive current in the rotating coordinate system represents the current in each sampling period. The d-axis component of the target drive current in the rotating coordinate system represents the target drive current for each sampling period.

[0029] In this embodiment of the application, determining the target rotor angle of the asynchronous motor for each sampling period based on the rotational speed and slip includes:

[0030] The target rotor angle of the asynchronous motor for each sampling period is determined according to formula (2):

[0031] θ=∫(ω sl Formula (2) for +ω)dt

[0032] Where θ represents the target rotor angle of the asynchronous motor in each sampling period, and ω represents the rotational speed of the asynchronous motor in each sampling period.

[0033] In this embodiment, the motor is a synchronous motor;

[0034] The target rotor angle of the motor for each sampling period is determined based on the rotational speed and the target drive current, including:

[0035] Obtain the rotor angle of the synchronous motor for each sampling period;

[0036] The target rotor angle of the synchronous motor for each sampling period is determined based on the rotational speed and rotor angle.

[0037] In this embodiment of the application, determining the predicted drive current of the motor for each sampling period based on the drive current and the target rotor angle includes:

[0038] The predicted drive current of the motor for each sampling period is determined according to formula (3):

[0039]

[0040] Among them, i sq i represents the q-axis component of the predicted drive current in the rotating coordinate system for each sampling period. sd i represents the d-axis component of the predicted drive current in the rotating coordinate system for each sampling period. o The zero-sequence component caused by three-phase imbalance is represented by θ, which represents the target rotor angle for each sampling period, and i a i b i c These represent the current components of the drive current in the three-phase coordinate system for each sampling period.

[0041] In this embodiment of the application, when it is determined that the first difference is not within the first preset range, a first preset response measure is executed, including:

[0042] If it is determined that the first difference is not within the first preset range, it is determined whether the drive current of the current sampling period exceeds the drive current threshold.

[0043] If the drive current in the current sampling period exceeds the drive current threshold, the motor is stopped.

[0044] If it is determined that the drive current in the current sampling period does not exceed the drive current threshold, the speed of the motor is reduced to the first preset speed.

[0045] In this embodiment of the application, when it is determined that the second difference is not within the second preset range, a second preset response measure is executed, including:

[0046] If it is determined that the second difference is not within the second preset range, it is determined whether the target drive current of the current sampling period exceeds the target drive current threshold.

[0047] If the target drive current in the current sampling period exceeds the target drive current threshold, the motor is controlled to stop.

[0048] If it is determined that the target drive current in the current sampling period does not exceed the target drive current threshold, the speed of the motor is reduced to the second preset speed.

[0049] In this embodiment of the application, if it is determined that the third difference is not within the third preset range, a third preset response measure is executed, including:

[0050] If it is determined that the third difference is not within the third preset range, determine whether the predicted drive current of the current sampling period exceeds the predicted drive current threshold.

[0051] If the predicted drive current in the current sampling period exceeds the predicted drive current threshold, the motor is controlled to stop.

[0052] If it is determined that the predicted drive current of the current sampling period does not exceed the predicted drive current threshold, the speed of the motor is reduced to the third preset speed.

[0053] A second aspect of this application provides a controller configured to perform the control method for tower cranes described above.

[0054] A third aspect of this application provides a control device for a tower crane, comprising:

[0055] A current detection device is configured to detect the drive current of the tower crane's motor in each sampling period; and

[0056] The aforementioned controller.

[0057] In this embodiment of the application, the control device further includes:

[0058] The encoder is configured to detect the motor speed for each sampling cycle.

[0059] A fourth aspect of this application provides a tower crane, including the aforementioned control device for the tower crane.

[0060] A fifth aspect of this application provides a machine-readable storage medium storing instructions that, when executed by a processor, configure the processor to perform the aforementioned control method for a tower crane.

[0061] The above technical solution involves acquiring the drive current of the tower crane's motor in each sampling period and determining whether the first difference between the drive current in the current sampling period and the drive current in the previous sampling period is within a first preset range. If the first difference is determined to be outside the first preset range, a first preset countermeasure is executed. In this way, rapid identification and automatic protection against sudden working conditions such as hoisting anchorage or sudden load changes are achieved, ensuring the reliable, safe, and efficient operation of the tower crane.

[0062] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0063] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings:

[0064] Figure 1 This is a flowchart illustrating the control method for tower cranes provided in the embodiments of this application;

[0065] Figure 2 This is another schematic flowchart of the control method for tower cranes provided in this embodiment of the invention;

[0066] Figure 3 This is another schematic flowchart of the control method for tower cranes provided in this embodiment of the invention;

[0067] Figure 4 This is a flowchart illustrating step S31 of the control method for tower cranes provided in the embodiments of this application;

[0068] Figure 5 This is another schematic flowchart of step S31 in the control method for tower cranes provided in the embodiments of this application;

[0069] Figure 6 This is a flowchart illustrating step S13 of the control method for a tower crane provided in the embodiments of this application;

[0070] Figure 7 This is a flowchart illustrating step S24 of the control method for tower cranes provided in the embodiments of this application;

[0071] Figure 8 This is a flowchart illustrating step S34 of the control method for tower cranes provided in the embodiments of this application;

[0072] Figure 9 This is a schematic diagram of the control device for tower cranes provided in the embodiments of this application;

[0073] Figure 10 This is an internal structural diagram of the computer device provided in the embodiments of this application.

[0074] Explanation of reference numerals in the attached figures

[0075] 10. Current detection equipment; 20. Controller;

[0076] 30. Encoder. Detailed Implementation

[0077] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0078] Figure 1 This is a flowchart illustrating the control method for tower cranes provided in the embodiments of this application. Figure 1 As shown in one embodiment of this application, a control method for a tower crane is provided, comprising the following steps:

[0079] Step S11: Obtain the drive current of the tower crane motor for each sampling period;

[0080] Step S12: Determine whether the first difference between the drive current of the current sampling period and the drive current of the previous sampling period is within a first preset range;

[0081] Step S13: If it is determined that the first difference is not within the first preset range, execute the first preset response measure.

[0082] Specifically, in step S11, the tower crane's motors include any one or more of the following: a hoisting motor that drives the hook to move up and down, a luffing motor that drives the luffing trolley to move back and forth, and a slewing motor that drives the slewing motion. During tower crane operation, the drive current of the motor can be detected in real time in each sampling cycle by a current detection device such as a Hall effect current sensor installed on the motor's frequency converter, and uploaded to the tower crane controller via a CAN (Controller Area Network) communication network or a high-speed EtherCAT (EtherControlAutomationTechnology) communication network. It is understood that the transmission link between the current detection device on the frequency converter and the tower crane controller is short, time-efficient, and has a fast detection speed. In step S12, the tower crane controller compares the drive current of the current sampling cycle with the drive current of the previous sampling cycle to determine whether the first difference between the two is within a first preset range. It is understood that the drive current of the motor detected by the current detection device is a three-phase AC current. Therefore, the tower crane controller can first extract the characteristic value of the three-phase AC current, and then compare the characteristic value of the drive current in the current sampling period with the characteristic value of the drive current in the previous sampling period. This characteristic value can be the peak value, average value, or effective value of the three-phase AC current, preferably the peak value. In step S13, when the first difference is not within the first preset range, for example, if the first difference exceeds 40% of the drive current in the previous sampling period, the tower crane controller determines that a sudden change in the motor's drive current has occurred, confirming that a sudden working condition such as hoisting anchorage or sudden load change has been detected. At this time, the first preset countermeasures are executed to avoid damage to the tower crane. It is understood that determining whether a sudden working condition such as hoisting anchorage or sudden load change has been detected based on whether the peak value of the motor's three-phase AC current has changed abruptly can be performed 6 times within one sampling period (2π), making the detection fast, convenient, and simple. Through the above methods, rapid identification and automatic protection against sudden working conditions such as hoisting anchorage or sudden load changes are achieved, ensuring the reliable, safe and efficient operation of the tower crane.

[0083] Please see Figure 2 , Figure 2 This is another schematic flowchart of the control method for tower cranes provided in this embodiment of the invention. For example... Figure 2 As shown, the control method may further include the following steps:

[0084] Step S21: Obtain the motor speed for each sampling period;

[0085] Step S22: Determine the target drive current of the motor for each sampling period based on the rotational speed and the target rotational speed of the motor;

[0086] Step S23: Determine whether the second difference between the target drive current of the current sampling period and the target drive current of the previous sampling period is within the second preset range;

[0087] Step S24: If it is determined that the second difference is not within the second preset range, execute the second preset response measure.

[0088] Specifically, in step S21, during tower crane operation, the motor speed can be detected in real time within each sampling cycle via the encoder on the frequency converter, and uploaded to the tower crane controller via a CAN communication network or a high-speed EtherCAT communication network. In step S22, the target motor speed is the speed the motor is expected to reach after the user inputs the operation command, and the target motor drive current is the expected drive current the motor can achieve. Since the tower crane uses a speed regulation mode, the motor drive current (output torque) adopts the principle of following the speed loop output. Therefore, the tower crane controller can determine the target motor drive current for each sampling cycle based on the motor speed and target speed in each sampling cycle, and then proceed to step S23. In step S23, the tower crane controller compares the target drive current of the current sampling cycle with the target drive current of the previous sampling cycle, and determines whether the second difference between the two is within a second preset range. It can be understood that the motor output torque is only related to the q-axis component of the motor drive current in the rotating coordinate system. Therefore, it is possible to compare only the q-axis component of the target drive current in the current sampling cycle with the q-axis component of the target drive current in the rotating coordinate system of the previous sampling cycle. In step S24, when the second difference is not within the second preset range, for example, if the second difference exceeds 20% of the target drive current of the previous sampling period, the tower crane controller determines that the target drive current of the motor has changed abruptly, and confirms that a sudden working condition such as hoisting anchorage or sudden load change has been detected in the tower crane. At this time, the second preset countermeasures are executed to avoid damage to the tower crane. It can be understood that judging whether a sudden working condition such as hoisting anchorage or sudden load change has been detected based on whether the target drive current of the motor has changed abruptly is equivalent to directly observing the torque current output of the speed controller. It can predict the abnormal working condition that is about to occur before the sudden working condition such as hoisting anchorage or sudden load change occurs, and the detection accuracy is higher.

[0089] In one embodiment, determining the target drive current of the motor for each sampling period based on the rotational speed and the target rotational speed of the motor in step S22 may include: performing PID calculation on the difference between the rotational speed and the target rotational speed of the motor to obtain the target drive current of the motor for each sampling period.

[0090] Specifically, PID (Proportion Integral Differential) is an algorithm that controls the motor by proportional (P), integral (I), and derivative (D) operations on the difference. P is the proportional operation, which involves multiplying the difference by a proportional coefficient; I is the integral operation, which involves integrating the difference with respect to time; and D is the derivative operation, which involves differentiating the difference with respect to time. The sum of the three results yields the target drive current of the motor for each sampling period.

[0091] Please see Figure 3 , Figure 3 This is another schematic flowchart of the control method for tower cranes provided in this embodiment of the invention. For example... Figure 3 As shown, the control method may further include the following steps:

[0092] Step S31: Determine the target rotor angle of the motor for each sampling cycle based on the rotational speed and the target drive current;

[0093] Step S32: Determine the predicted drive current of the motor for each sampling period based on the drive current and the target rotor angle;

[0094] Step S33: Determine whether the third difference between the predicted drive current of the current sampling period and the predicted drive current of the previous sampling period is within the third preset range.

[0095] Step S34: If it is determined that the third difference is not within the third preset range, execute the third preset response measures.

[0096] Specifically, in step S31, the target rotor angle of the motor is the angle corresponding to the position that the motor rotor is expected to reach. Based on the motor's control principle, the tower crane controller can determine the target rotor angle of the motor for each sampling period based on the motor's speed and target drive current. In step S32, the predicted drive current of the motor is the predicted actual drive current that the motor can reach. The tower crane controller can determine the predicted drive current of the motor for each sampling period based on the motor's drive current and the target rotor angle. In step S33, the tower crane controller compares the predicted drive current of the current sampling period with the predicted drive current of the previous sampling period, determining whether the third difference between the two is within a third preset range. It can be understood that, similarly, the q-axis component of the predicted drive current in the current sampling period in the rotating coordinate system can be compared separately with the q-axis component of the predicted drive current in the previous sampling period in the rotating coordinate system. In step S34, when the third difference is not within the third preset range, for example, if the third difference exceeds 10% of the predicted drive current of the previous sampling period, the tower crane controller determines that a sudden change has occurred in the predicted drive current of the motor, confirming that a sudden working condition such as hoisting anchorage or sudden load change has been detected. At this time, the third preset countermeasures are executed to avoid damage to the tower crane. It can be understood that determining whether a sudden working condition such as hoisting anchorage or sudden load change has been detected based on whether the predicted drive current of the motor has changed is equivalent to directly observing the actual torque that the motor will output, further improving the detection accuracy.

[0097] In practical applications, the motors on tower cranes can be either asynchronous or synchronous. The rotor rotation speed of an asynchronous motor differs from the stator magnetic field rotation speed, while the rotor rotation speed of a synchronous motor is the same as the stator magnetic field rotation speed. When the motors are asynchronous and synchronous, the specific process of determining the target rotor angle for each sampling period based on the rotational speed and target drive current in step S31 differs, and will be explained separately below.

[0098] In one embodiment, the motor is an asynchronous motor. See also... Figure 4 , Figure 4 This is a flowchart illustrating step S31 of the control method for a tower crane provided in this application embodiment. Determining the target rotor angle of the motor for each sampling cycle based on the rotational speed and target drive current in step S31 may include the following steps:

[0099] Step S311: Determine the slip of the asynchronous motor for each sampling period based on the target drive current;

[0100] Step S312: Determine the target rotor angle of the asynchronous motor for each sampling period based on the rotational speed and slip.

[0101] Specifically, in step S311, the slip of the asynchronous motor is the ratio of the difference between the rotational speed of the stator magnetic field and the rotational speed of the rotor to the rotational speed of the stator magnetic field. The tower crane controller determines the expected slip of the asynchronous motor in each sampling period based on the expected drive current, and then proceeds to step S312. In step S312, the tower crane controller determines the angle corresponding to the expected rotor position of the asynchronous motor in each sampling period based on the motor's rotational speed and the expected slip.

[0102] In one embodiment, determining the slip of the asynchronous motor for each sampling period based on the target drive current includes:

[0103] The slip of the asynchronous motor for each sampling period is determined according to formula (1):

[0104]

[0105] Where, ω sl τ represents the slip of the asynchronous motor for each sampling period. r The rotor time constant of the asynchronous motor is represented by s, where s represents the differential operator. The q-axis component of the target drive current in the rotating coordinate system represents the current in each sampling period. The d-axis component of the target drive current in the rotating coordinate system represents the target drive current for each sampling period.

[0106] In one embodiment, determining the target rotor angle of the asynchronous motor for each sampling period based on the rotational speed and slip includes:

[0107] The target rotor angle of the asynchronous motor for each sampling period is determined according to formula (2):

[0108] θ=∫(ω sl Formula (2) for +ω)dt

[0109] Where θ represents the target rotor angle of the asynchronous motor in each sampling period, and ω represents the rotational speed of the asynchronous motor in each sampling period.

[0110] Specifically, the target drive current of the asynchronous motor can first be transformed by coordinate transformation to obtain the q-axis component of the target drive current in the rotating coordinate system. and d-axis components Then, the slip of the asynchronous motor is calculated using formula (1), and the target rotor angle of the asynchronous motor is calculated using formula (2).

[0111] In one embodiment, the motor is a synchronous motor. See also... Figure 5 , Figure 5 This is another flowchart illustrating step S31 of the control method for tower cranes provided in this application embodiment. Determining the target rotor angle of the motor for each sampling cycle based on the rotational speed and target drive current in step S31 may include the following steps:

[0112] Step S313: Obtain the rotor angle of the synchronous motor for each sampling period;

[0113] Step S314: Determine the target rotor angle of the synchronous motor for each sampling period based on the rotational speed and rotor angle.

[0114] Specifically, in step S313, the rotor angle of the synchronous motor is the angle corresponding to the rotor position of the synchronous motor in the current sampling period. During the operation of the tower crane, the rotor angle of the synchronous motor can be detected in real time in each sampling period by an encoder, and uploaded to the tower crane controller via a CAN communication network or a high-speed EtherCAT communication network. In step S314, the tower crane controller can determine the angle corresponding to the expected rotor position of the synchronous motor in each sampling period based on the rotational speed and rotor angle of the synchronous motor in each sampling period.

[0115] In one embodiment, determining the predicted drive current of the motor for each sampling period based on the drive current and the target rotor angle includes:

[0116] The predicted drive current of the motor for each sampling period is determined according to formula (3):

[0117]

[0118] Among them, i sq i represents the q-axis component of the predicted drive current in the rotating coordinate system for each sampling period. sd i represents the d-axis component of the predicted drive current in the rotating coordinate system for each sampling period. o The zero-sequence component caused by three-phase imbalance is represented by θ, which represents the target rotor angle for each sampling period, and i a i b i c These represent the current components of the drive current in the three-phase coordinate system for each sampling period.

[0119] Specifically, the three-phase drive current i of the motor is obtained. a i b i cAfterwards, a static coordinate transformation can be performed first, followed by a dynamic coordinate transformation. The q-axis and d-axis components of the predicted driving current in the rotating coordinate system can be calculated using formula (3). In subsequent steps, the q-axis component of the predicted driving current in the rotating coordinate system in the current sampling period can be compared separately with the q-axis component of the predicted driving current in the rotating coordinate system in the previous sampling period.

[0120] In practical applications, the motor's output torque can more intuitively reflect the motor's working state. Therefore, the motor's predicted output torque can be further determined based on the motor's predicted drive current, that is, the predicted torque that the motor can actually output.

[0121] In one embodiment, when the motor is an asynchronous motor, the predicted output torque of the motor can be determined by formula (4):

[0122] T e =K·i sd ·i sq Formula (4)

[0123] Among them, T e This represents the predicted output torque of the motor, and K represents a constant related to the motor's construction.

[0124] In one embodiment, when the motor is a built-in permanent magnet synchronous motor, the predicted output torque of the motor can be determined by formula (5):

[0125]

[0126] In one embodiment, when the motor is a surface-mounted permanent magnet synchronous motor, the predicted output torque of the motor can be determined by formula (6):

[0127]

[0128] Among them, L d L represents the direct-axis inductance of the motor. q The quadrature-axis inductance of the motor, λ f The permanent magnet flux linkage represents the motor.

[0129] By synchronously observing whether the predicted drive torque of the motor changes abruptly, the detection accuracy for sudden working conditions such as hoisting, anchoring, or sudden load changes can be further improved.

[0130] Please see Figure 6 , Figure 6 This is a flowchart illustrating step S13 of the control method for a tower crane provided in this application embodiment. The execution of the first preset response measure in step S13 when it is determined that the first difference is not within the first preset range may include the following steps:

[0131] Step S131: If it is determined that the first difference is not within the first preset range, determine whether the driving current of the current sampling period exceeds the driving current threshold.

[0132] Step S132: If it is determined that the drive current in the current sampling period exceeds the drive current threshold, control the motor to stop;

[0133] Step S133: If it is determined that the drive current of the current sampling period does not exceed the drive current threshold, the speed of the motor is reduced to the first preset speed.

[0134] Please see Figure 7 , Figure 7 This is a flowchart illustrating step S24 of the control method for tower cranes provided in this application embodiment. Step S24, in which a second preset response is executed when it is determined that the second difference is not within the second preset range, may include the following steps:

[0135] Step S241: If it is determined that the second difference is not within the second preset range, determine whether the target drive current of the current sampling period exceeds the target drive current threshold.

[0136] Step S242: If it is determined that the target drive current in the current sampling period exceeds the target drive current threshold, control the motor to stop;

[0137] Step S243: If it is determined that the target drive current of the current sampling period does not exceed the target drive current threshold, the speed of the motor is reduced to the second preset speed.

[0138] Please see Figure 8 , Figure 8 This is a flowchart illustrating step S34 of the control method for tower cranes provided in this application embodiment. Step S34, in which the third difference is determined to be outside the third preset range, involves executing a third preset response measure, which may include the following steps:

[0139] Step S341: If it is determined that the third difference is not within the third preset range, determine whether the predicted drive current of the current sampling period exceeds the predicted drive current threshold.

[0140] Step S342: If it is determined that the predicted drive current of the current sampling period exceeds the predicted drive current threshold, control the motor to stop;

[0141] Step S343: If it is determined that the predicted drive current of the current sampling period does not exceed the predicted drive current threshold, the speed of the motor is reduced to the third preset speed.

[0142] Specifically, in the aforementioned embodiments, the drive current threshold, target drive current threshold, and predicted drive current threshold are the limit values ​​of the drive current, target drive current, and predicted drive current of the motor during normal operation, respectively. These can be set according to actual needs. The first preset speed, second preset speed, and third preset speed can be equal or unequal, but are preferably equal, for example, all set to microspeed. When the first difference is not within the first preset range, or the second difference is not within the second preset range, or the third difference is not within the third preset range, it indicates that the tower crane has encountered a sudden situation. Further judgment is needed to determine whether the drive current, target drive current, and predicted drive current of the current sampling period exceed their respective limit values ​​to decide what countermeasures to take. When any one of the drive current, target drive current, and predicted drive current of the current sampling period exceeds its own limit value, it can be determined that the tower crane is experiencing an anchoring issue, at which point the motor is stopped. For example, when a tower crane is lifting its hook, if it gets caught on a fixed object and becomes overloaded, or if multiple loads are being lifted in a series and the crane is overloaded, or if the weight sensor malfunctions, causing a sudden increase in the drive current, target drive current, and predicted drive current of the hoisting motor in the current sampling period, exceeding its own limits, the tower crane controller can determine that the crane is experiencing an anchored object situation and immediately stop the hoisting motor to prevent the crane from rising. If the drive current, target drive current, and predicted drive current in the current sampling period do not exceed their own limits, it can be determined that the tower crane is experiencing a variable load slow-start situation, and the motor speed can be reduced to a very low speed. For example, when the tower crane is lifting its hook, if the cargo gets caught on a lighter object such as scaffolding, or if multiple loads are being lifted in series using flexible ropes, or if the ropes are tightened before lifting, causing a sudden increase in the drive current, target drive current, and predicted drive current of the hoisting motor in the current sampling period, but not exceeding its own limits, it can be determined that the tower crane is experiencing a variable load slow-start situation, and the motor speed can be reduced to a very low speed; if necessary, the motor can also be stopped.

[0143] The above technical solution involves acquiring the drive current of the tower crane's motor in each sampling period and determining whether the first difference between the drive current in the current sampling period and the drive current in the previous sampling period is within a first preset range. If the first difference is determined to be outside the first preset range, a first preset countermeasure is executed. In this way, rapid identification and automatic protection against sudden working conditions such as hoisting anchorage or sudden load changes are achieved, ensuring the reliable, safe, and efficient operation of the tower crane.

[0144] This application embodiment also provides a controller, which is configured to perform the following method: acquiring the drive current of the tower crane motor in each sampling period; determining whether a first difference between the drive current of the current sampling period and the drive current of the previous sampling period is within a first preset range; and executing a first preset response measure if it is determined that the first difference is not within the first preset range.

[0145] In one embodiment, the method further includes: acquiring the motor speed in each sampling period; determining the target drive current of the motor in each sampling period based on the motor speed and the target motor speed; determining whether a second difference between the target drive current in the current sampling period and the target drive current in the previous sampling period is within a second preset range; and executing a second preset response measure if the second difference is determined not to be within the second preset range.

[0146] In one embodiment, determining the target drive current of the motor for each sampling period based on the rotational speed and the target rotational speed of the motor includes: performing PID calculation on the difference between the rotational speed and the target rotational speed of the motor to obtain the target drive current of the motor for each sampling period.

[0147] In one embodiment, the method further includes: determining the target rotor angle of the motor for each sampling period based on the rotational speed and the target drive current; determining the predicted drive current of the motor for each sampling period based on the drive current and the target rotor angle; determining whether a third difference between the predicted drive current of the current sampling period and the predicted drive current of the previous sampling period is within a third preset range; and executing a third preset response measure if the third difference is determined not to be within the third preset range.

[0148] In one embodiment, the motor is an asynchronous motor; determining the target rotor angle of the motor for each sampling period based on the rotational speed and the target drive current includes: determining the slip of the asynchronous motor for each sampling period based on the target drive current; and determining the target rotor angle of the asynchronous motor for each sampling period based on the rotational speed and the slip.

[0149] In one embodiment, determining the slip of the asynchronous motor for each sampling period based on the target drive current includes: determining the slip of the asynchronous motor for each sampling period according to formula (1):

[0150]

[0151] Where, ω sl τ represents the slip of the asynchronous motor for each sampling period. r The rotor time constant of the asynchronous motor is represented by s, where s represents the differential operator. The q-axis component of the target drive current in the rotating coordinate system represents the current in each sampling period. The d-axis component of the target drive current in the rotating coordinate system represents the target drive current for each sampling period.

[0152] In one embodiment, determining the target rotor angle of the asynchronous motor for each sampling period based on the rotational speed and slip includes: determining the target rotor angle of the asynchronous motor for each sampling period according to formula (2):

[0153] θ=∫(ω sl Formula (2) for +ω)dt

[0154] Where θ represents the target rotor angle of the asynchronous motor in each sampling period, and ω represents the rotational speed of the asynchronous motor in each sampling period.

[0155] In one embodiment, the motor is a synchronous motor; determining the target rotor angle of the motor for each sampling period based on the rotational speed and the target drive current includes: acquiring the rotor angle of the synchronous motor for each sampling period; and determining the target rotor angle of the synchronous motor for each sampling period based on the rotational speed and the rotor angle.

[0156] In one embodiment, determining the predicted drive current of the motor for each sampling period based on the drive current and the target rotor angle includes: determining the predicted drive current of the motor for each sampling period according to formula (3):

[0157]

[0158] Among them, i sq i represents the q-axis component of the predicted drive current in the rotating coordinate system for each sampling period. sd i represents the d-axis component of the predicted drive current in the rotating coordinate system for each sampling period. o The zero-sequence component caused by three-phase imbalance is represented by θ, which represents the target rotor angle for each sampling period, and i a i b i c These represent the current components of the drive current in the three-phase coordinate system for each sampling period.

[0159] In one embodiment, if it is determined that the first difference is not within the first preset range, a first preset response measure is executed, including: if it is determined that the first difference is not within the first preset range, determining whether the drive current of the current sampling period exceeds the drive current threshold; if it is determined that the drive current of the current sampling period exceeds the drive current threshold, controlling the motor to stop; if it is determined that the drive current of the current sampling period does not exceed the drive current threshold, controlling the motor speed to decrease to the first preset speed.

[0160] In one embodiment, if it is determined that the second difference is not within the second preset range, a second preset response measure is executed, including: if it is determined that the second difference is not within the second preset range, determining whether the target drive current of the current sampling period exceeds the target drive current threshold; if it is determined that the target drive current of the current sampling period exceeds the target drive current threshold, controlling the motor to stop; if it is determined that the target drive current of the current sampling period does not exceed the target drive current threshold, controlling the motor speed to decrease to the second preset speed.

[0161] In one embodiment, if it is determined that the third difference is not within the third preset range, a third preset response measure is executed, including: if it is determined that the third difference is not within the third preset range, determining whether the predicted drive current of the current sampling period exceeds the predicted drive current threshold; if it is determined that the predicted drive current of the current sampling period exceeds the predicted drive current threshold, controlling the motor to stop; if it is determined that the predicted drive current of the current sampling period does not exceed the predicted drive current threshold, controlling the motor speed to decrease to the third preset speed.

[0162] Please see Figure 9 , Figure 9 This is a schematic diagram of the control device for a tower crane provided in an embodiment of this application. Figure 9 As shown, in one embodiment of this application, a control device for a tower crane is provided, comprising:

[0163] Current detection device 10 is configured to detect the drive current of the tower crane's motor in each sampling period; and

[0164] Controller 20 is configured to execute the control method described above for tower cranes.

[0165] Furthermore, in one embodiment, the control device further includes:

[0166] Encoder 30 is configured to detect the motor speed in each sampling cycle.

[0167] Specifically, the current detection device 10 can be a Hall-effect current sensor, which is installed on the frequency converter of the motor, and the encoder 30 can be built into the frequency converter.

[0168] It should be noted that the apparatus provided in the above embodiments is only illustrated by the division of the above program modules when performing related operations. In actual applications, the above processing can be assigned to different program modules as needed, that is, the internal structure of the terminal can be divided into different program modules to complete all or part of the processing described above. In addition, the apparatus provided in the above embodiments and the method embodiments in the above embodiments belong to the same concept, and the specific implementation process can be found in the method embodiments, which will not be repeated here.

[0169] Based on the hardware implementation of the above program modules, and in order to implement the method of the embodiments of this application, the embodiments of this application also provide a tower crane, including the above-described control device for the tower crane.

[0170] In one embodiment, the tower crane may further include:

[0171] A communication interface enables information exchange with other devices (such as network devices, terminals, etc.);

[0172] A processor, connected to a communication interface to enable information interaction with other devices, and used to execute the methods provided by one or more of the above-mentioned technical solutions when running computer programs;

[0173] Memory is used to store computer programs that can run on a processor.

[0174] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured, and the methods provided by one or more of the aforementioned technical solutions can be implemented by adjusting the kernel parameters.

[0175] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0176] It should be noted that the specific process by which the processor performs the above operations is detailed in the method implementation examples, and will not be repeated here.

[0177] In practical applications, the various components of a tower crane can be coupled together via a bus system. This bus system is used to enable communication and connection between these components. In addition to a data bus, the bus system also includes a power bus, a control bus, and a status signal bus.

[0178] The memory in this application embodiment is used to store various types of data to support the operation of the tower crane. Examples of this data include any computer programs used for operation on the tower crane.

[0179] The methods disclosed in the embodiments of this application can be applied to a processor or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor may be a general-purpose processor, a digital signal processor (DSP), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. A general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the methods disclosed in the embodiments of this application can be directly manifested as execution by a hardware decoding processor, or execution by a combination of hardware and software modules in the decoding processor. The software modules may be located in a storage medium, which is located in memory. The processor reads information from the memory and, in conjunction with its hardware, completes the steps of the aforementioned method.

[0180] In an exemplary embodiment, the processor may be implemented by one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers (MCUs), microprocessors, or other electronic components to perform the aforementioned method.

[0181] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or both. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), ferromagnetic random access memory (FRAM), flash memory, magnetic surface memory, optical disc, or compact disc read-only memory (CD ROM); magnetic surface memory can be disk storage or magnetic tape storage. Volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Synchronous Static Random Access Memory (SSRAM), Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDRSDRAM), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM), SyncLink Dynamic Random Access Memory (SLDRAM), and Direct Rambus Random Access Memory (DRRAM).The memories described in the embodiments of this application are intended to include, but are not limited to, these and any other suitable types of memories.

[0182] This application also provides a machine-readable storage medium storing instructions that, when executed by a processor, cause the processor to perform the aforementioned control method for tower cranes.

[0183] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 10 As shown. The computer device includes a processor A01, a network interface A02, a display screen A04, an input device A05, and a memory (not shown) connected via a system bus. The processor A01 provides computing and control capabilities. The memory includes internal memory A03 and a non-volatile storage medium A06. The non-volatile storage medium A06 stores an operating system B01 and a computer program B02. The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 stored in the non-volatile storage medium A06. The network interface A02 is used for communication with external terminals via a network connection. When the computer program is executed by the processor A01, it implements the method of any of the above embodiments. The display screen A04 can be a liquid crystal display or an electronic ink display. The input device A05 can be a touch layer covering the display screen, a button, trackball, or touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0184] Those skilled in the art will understand that Figure 10 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0185] This application also provides an apparatus, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it implements the method of any of the above embodiments.

[0186] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0187] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0188] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0189] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0190] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0191] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0192] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0193] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0194] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A control method for tower cranes, used to respond to sudden operating conditions of tower cranes, characterized in that, include: Obtain the drive current of the tower crane's motor for each sampling period; Determine whether the first difference between the drive current in the current sampling period and the drive current in the previous sampling period is within a first preset range; If it is determined that the first difference is not within the first preset range, and it is determined that the tower crane has experienced a sudden working condition, the first preset response measures will be executed. The step of determining that a sudden working condition has occurred in the tower crane and executing the first preset response measures when it is determined that the first difference is not within the first preset range includes: If it is determined that the first difference is not within the first preset range, it is determined whether the driving current of the current sampling period exceeds the driving current threshold. If it is determined that the drive current in the current sampling period exceeds the drive current threshold, it is determined that the tower crane is in a state of anchoring an object, and the motor is controlled to stop. If it is determined that the driving current in the current sampling period does not exceed the driving current threshold, it is determined that the tower crane is in a variable load slow start state, and the speed of the motor is controlled to be reduced to a first preset speed.

2. The control method according to claim 1, characterized in that, Also includes: Obtain the motor speed for each sampling period; The target drive current of the motor is determined for each sampling period based on the rotational speed and the target rotational speed of the motor. Determine whether the second difference between the target drive current in the current sampling period and the target drive current in the previous sampling period is within a second preset range; If it is determined that the second difference is not within the second preset range, the second preset response measure is executed.

3. The control method according to claim 2, characterized in that, The step of determining the target drive current of the motor for each sampling period based on the rotational speed and the target rotational speed of the motor includes: The difference between the rotational speed and the target rotational speed of the motor is used to perform PID calculations to obtain the target drive current of the motor for each sampling period.

4. The control method according to claim 2, characterized in that, Also includes: The target rotor angle of the motor is determined for each sampling period based on the rotational speed and the target drive current. The predicted drive current of the motor for each sampling period is determined based on the drive current and the target rotor angle. Determine whether the third difference between the predicted drive current in the current sampling period and the predicted drive current in the previous sampling period is within a third preset range; If it is determined that the third difference is not within the third preset range, the third preset response measure shall be executed.

5. The control method according to claim 4, characterized in that, The motor is an asynchronous motor; Determining the target rotor angle of the motor for each sampling period based on the rotational speed and the target drive current includes: The slip of the asynchronous motor for each sampling period is determined based on the target drive current; The target rotor angle of the asynchronous motor for each sampling period is determined based on the rotational speed and the slip.

6. The control method according to claim 5, characterized in that, The step of determining the slip of the asynchronous motor for each sampling period based on the target drive current includes: The slip of the asynchronous motor for each sampling period is determined according to formula (1): Formula (1) in, The slip of the asynchronous motor represents the slip of the motor in each sampling period. This represents the rotor time constant of the asynchronous motor. Represents the differential operator, The q-axis component of the target driving current in the rotating coordinate system represents each sampling period. The d-axis component of the target drive current in the rotating coordinate system represents each sampling period.

7. The control method according to claim 6, characterized in that, The step of determining the target rotor angle of the asynchronous motor for each sampling period based on the rotational speed and the slip includes: The target rotor angle of the asynchronous motor for each sampling period is determined according to formula (2): Formula (2) in, The target rotor angle of the asynchronous motor represents each sampling period. This represents the rotational speed of the asynchronous motor for each sampling period.

8. The control method according to claim 4, characterized in that, The motor is a synchronous motor; Determining the target rotor angle of the motor for each sampling period based on the rotational speed and the target drive current includes: Obtain the rotor angle of the synchronous motor for each sampling period; The target rotor angle of the synchronous motor for each sampling period is determined based on the rotational speed and the rotor angle.

9. The control method according to claim 4, characterized in that, The step of determining the predicted drive current of the motor for each sampling period based on the drive current and the target rotor angle includes: The predicted drive current of the motor for each sampling period is determined according to formula (3): Formula (3) in, The q-axis component of the predicted drive current in the rotating coordinate system represents each sampling period. The d-axis component of the predicted drive current in the rotating coordinate system represents each sampling period. This represents the zero-sequence component caused by three-phase imbalance. The target rotor angle represents each sampling period. These represent the current components of the driving current in the three-phase coordinate system for each sampling period.

10. The control method according to claim 2, characterized in that, The step of executing a second preset response when it is determined that the second difference is not within the second preset range includes: If it is determined that the second difference is not within the second preset range, it is determined whether the target drive current of the current sampling period exceeds the target drive current threshold. If the target drive current in the current sampling period exceeds the target drive current threshold, the motor is controlled to stop. If it is determined that the target drive current in the current sampling period does not exceed the target drive current threshold, the speed of the motor is controlled to be reduced to a second preset speed.

11. The control method according to claim 4, characterized in that, The step of executing a third preset response measure when it is determined that the third difference is not within the third preset range includes: If it is determined that the third difference is not within the third preset range, it is determined whether the predicted drive current of the current sampling period exceeds the predicted drive current threshold. If it is determined that the predicted drive current in the current sampling period exceeds the predicted drive current threshold, the motor is controlled to stop. If it is determined that the predicted drive current in the current sampling period does not exceed the predicted drive current threshold, the speed of the motor is controlled to be reduced to a third preset speed.

12. A controller, characterized in that, It is configured to perform the control method for tower cranes according to any one of claims 1 to 11.

13. A control device for a tower crane, characterized in that, include: The current detection device is configured to detect the drive current of the tower crane's motor in each sampling cycle; as well as The controller according to claim 12.

14. The control device according to claim 13, characterized in that, Also includes: The encoder is configured to detect the rotational speed of the motor in each sampling cycle.

15. A tower crane, characterized in that, Includes the control device for tower cranes as described in claim 14.

16. A machine-readable storage medium storing instructions thereon, characterized in that, When executed by a processor, the instruction causes the processor to be configured to perform the control method for a tower crane according to any one of claims 1 to 11.

Images