Slewing control method, tower crane and storage medium

Abstract

The present invention discloses a slewing control method, a tower crane, and a storage medium. The method comprises: obtaining motor speed and boom slewing speed in real time; correcting the current command speed according to a preset correction model to obtain the current corrected command speed; adjusting the motor speed according to the current boom slewing speed and the corrected command speed; and controlling the motor operation according to the adjusted motor speed. The present invention solves the problem of boom shaking and unstable slewing during the slewing motion of existing tower cranes.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery, and more particularly to a slewing control method, a tower crane, and a computer-readable storage medium. Background Technology

[0002] The slewing mechanism is a crucial component for enabling tower cranes to lift and move loads. The slewing mechanism of a tower crane is a high-inertia elastic load. Due to the long boom, it has a large inertia and undergoes significant elastic deformation during acceleration and deceleration, resulting in vibration and an unstable slewing process. Summary of the Invention

[0003] The main objective of this invention is to propose a slewing control method, a tower crane, and a computer-readable storage medium, aiming to solve the problems of boom shaking and unstable slewing during the existing tower crane's slewing motion.

[0004] To achieve the above objectives, the present invention provides a slewing control method, comprising the following steps:

[0005] Get the current command speed and boom rotation speed;

[0006] The current instruction speed is corrected according to the preset correction model to obtain the current corrected instruction speed;

[0007] Adjust the motor speed based on the current boom rotation speed and the correction command speed;

[0008] The motor is controlled to run according to the adjusted motor speed.

[0009] Optionally, the step of obtaining the current boom rotation speed includes:

[0010] Get the current motor speed;

[0011] The boom rotation speed is obtained based on the current motor speed and the preset boom rotation speed estimation model.

[0012] Optionally, the step of obtaining the current boom rotation speed further includes:

[0013] Acquire the current boom rotation speed sent by the speed sensor.

[0014] Optionally, the step of controlling the motor operation according to the adjusted motor speed includes:

[0015] Based on the adjusted motor speed, corresponding output frequency and voltage control signals are generated to control the motor operation.

[0016] Optionally, the step of obtaining the current command speed and boom rotation speed further includes:

[0017] Obtain the current command speed, motor speed, and boom rotation speed;

[0018] The step of adjusting the motor speed based on the current boom rotation speed and the correction command speed includes:

[0019] Based on the current boom slewing speed, correction command speed, and motor speed, obtain the current estimated tower deformation angle and the current theoretical tower deformation angle.

[0020] Adjust the motor speed based on the estimated angle of the current tower deformation and the theoretical angle of the current tower deformation.

[0021] Optionally, the step of obtaining the current estimated tower deformation angle and the current theoretical tower deformation angle based on the current boom slewing speed, correction command speed, and motor speed includes:

[0022] Based on the preset tower deformation angle estimation module and the current boom rotation speed and motor speed, the current tower deformation estimated angle is obtained.

[0023] Based on the current correction command speed and boom slewing speed, the current theoretical angle of tower deformation is obtained.

[0024] Optionally, the step of obtaining the current estimated tower deformation angle and the current theoretical tower deformation angle based on the current boom slewing speed, correction command speed, and motor speed includes:

[0025] Based on the preset tower deformation angle estimation module and the current boom rotation speed and motor speed, the current tower deformation estimated angle is obtained.

[0026] Based on the current estimated angle of tower deformation and the calculation model of the first preset theoretical angle of tower deformation, the current theoretical angle of tower deformation is obtained.

[0027] Optionally, the step of obtaining the current estimated tower deformation angle and the current theoretical tower deformation angle based on the current boom slewing speed, correction command speed, and motor speed includes:

[0028] Based on the preset tower deformation angle estimation module and the current boom rotation speed and motor speed, the current tower deformation estimated angle is obtained.

[0029] Based on the current tower deformation estimation angle and the second preset tower deformation theoretical angle calculation model, the current tower deformation theoretical angle is obtained.

[0030] To achieve the above objectives, the present invention also provides a tower crane, which includes a motor, a reducer, a frequency converter, a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the steps of the slewing control method as described above.

[0031] To achieve the above objectives, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the rotation control method described above.

[0032] This invention proposes a slewing control method, a tower crane, and a computer-readable storage medium. The method involves acquiring the current command speed and boom slewing speed; correcting the current command speed according to a preset correction model to obtain the current corrected command speed; adjusting the motor speed based on the current boom slewing speed and the corrected command speed; and controlling the motor operation based on the adjusted motor speed. Because this invention corrects the command speed, the acceleration and deceleration curves are smoother. Simultaneously, by adjusting the motor speed feedback to tower crane boom slewing speed feedback, the inverter's control object is effectively changed from the motor to direct control of the tower crane boom. Therefore, the above methods result in smoother slewing. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the first embodiment of the rotary control method of the present invention.

[0034] Figure 2 This is a flowchart illustrating the second embodiment of the rotary control method of the present invention.

[0035] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0036] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0037] In various embodiments of the present invention, the tower crane includes components such as an operating platform, a frequency converter, a motor, a reducer, a communication module, a memory, and a processor. The frequency converter is connected to both the motor and the operating platform. Those skilled in the art will understand that the tower crane may also include more or fewer components than shown in the figures, or combine certain components, or have different component arrangements. The processor is connected to both the memory and the communication module. The memory stores a computer program, which is simultaneously executed by the processor.

[0038] The communication module can connect to external devices via a network. It can receive data from external devices and also send data, instructions, and information to those external devices, which may include base stations, other tower cranes, mobile phones, tablets, laptops, and desktop computers.

[0039] The memory is used to store software programs and various data. It primarily comprises a program storage area and a data storage area. The program storage area stores the operating system, at least one application program required for a given function (the inner packaging box dimensions are determined based on the accessory's size parameters and packing quantity), etc. The data storage area stores data or information generated based on the use of the tower crane. Furthermore, the memory may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0040] The processor is the control center of a tower crane. It connects various parts of the tower crane via various interfaces and lines, including connecting to frequency converters and motors. By running or executing software programs and / or modules stored in memory, and by calling data stored in memory, it performs various functions and processes data, thereby providing overall monitoring of the tower crane. The processor may include one or more processing units. It may integrate an application processor and a modem processor. The application processor primarily handles the operating system, user interface, and applications, while the modem processor primarily handles wireless communication. It is understood that the modem processor may also be independent of integration into the processor.

[0041] However, the tower cranes mentioned above may also include a circuit control module, which is used to connect to the mains power supply to realize power control and ensure the normal operation of other components.

[0042] Those skilled in the art will understand that the structure of a tower crane does not constitute a limitation on the tower crane, and may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0043] Based on the above hardware structure, various embodiments of the method of the present invention are proposed.

[0044] Reference Figure 1 In a first embodiment of the slewing control method of the present invention, the slewing control method includes the following steps:

[0045] Step S10: Obtain the current command speed and boom rotation speed;

[0046] In this solution, the tower crane includes an operating platform, a frequency converter, a motor, a reducer, and a boom. The operating platform is connected to the frequency converter, which is connected to the motor, and the motor is connected to the reducer. The tower crane operator inputs operating commands through the operating platform, which then transmits these commands to the frequency converter. The frequency converter converts the input commands into a corresponding speed control curve. Based on the speed control curve, the frequency converter obtains the current commanded speed and also acquires the current boom slewing speed in real time.

[0047] The boom slewing speed can be obtained through feedback from a speed sensor installed on the boom, or it can be obtained through a boom slewing speed estimation model. Specifically, the step of obtaining the current boom slewing speed in step S10 includes:

[0048] Step S11: Obtain the current motor speed;

[0049] Step S12: Obtain the boom rotation speed based on the current motor speed and the preset boom rotation speed estimation model.

[0050] The frequency converter obtains the current motor speed through feedback from the encoder on the motor, or through other means; this is not limited or specifically described here. The current motor speed is input into a preset boom slewing speed estimation model, and the output boom slewing speed is determined. The preset boom slewing speed estimation model is as follows:

[0051]

[0052] Where r2 is the radius of the large gear in the tower crane jib drive gear of the tower crane slewing mechanism, r1 is the radius of the small gear in the tower crane jib drive gear of the tower crane slewing mechanism, K1 is the reduction ratio of the reducer in the tower crane slewing mechanism, and J d For the moment of inertia of the upper arm, ω d Let ω be the rotational speed of the boom. m Let s represent the motor speed, and s represent the derivative.

[0053] Furthermore, considering the effects of the tower's torsional stiffness, the jib's moment of inertia, and the damping coefficient, the pre-set jib rotation speed estimation model can also be:

[0054]

[0055] Where r2 is the radius of the large gear in the tower crane jib drive gear of the tower crane slewing mechanism, r1 is the radius of the small gear in the tower crane jib drive gear of the tower crane slewing mechanism, K1 is the reduction ratio of the reducer in the tower crane slewing mechanism, and J d For the moment of inertia of the upper arm, ω d Let ω be the rotational speed of the boom. mLet s represent the motor speed, s represent the differential, and K represent the speed of the motor. f K is the damping coefficient of the boom. t To enhance the torsional stiffness of the tower.

[0056] Step S20: Correct the current instruction speed according to the preset correction model to obtain the current corrected instruction speed;

[0057] The frequency converter corrects the speed control curve corresponding to the operation command according to the preset correction model to obtain the corrected speed control curve, and then obtains the current corrected command speed according to the corrected speed control curve.

[0058] Specifically, the corrected model consists of a differential element and a first-order inertial element, with the time constant τ and proportional coefficient K set to preset values. The corrected model is as follows:

[0059]

[0060] ω Ref The commanded speed is represented by α, and the acceleration of the motor is represented by ω. comp ω represents the velocity after acceleration has been filtered by a first-order inertial filter. m τ represents the corrected command speed of the motor, K represents the proportional coefficient, and s represents the derivative.

[0061] Step S30: Adjust the motor speed according to the current boom rotation speed and the correction command speed;

[0062] The frequency converter uses the current boom slewing speed as feedback to further adjust the correction command speed. For example, it can use PID control to adjust the correction command speed and obtain the adjusted motor speed.

[0063] Step S40: Control the motor to run according to the adjusted motor speed.

[0064] The frequency converter generates corresponding output frequency and voltage control signals based on the adjusted motor speed to control the motor operation.

[0065] This example obtains the current command speed and boom slewing speed; corrects the current command speed according to a preset correction model to obtain the current corrected command speed; adjusts the motor speed based on the current boom slewing speed and the corrected command speed; and controls the motor operation based on the adjusted motor speed. Because the command speed is corrected, the acceleration and deceleration curves are smoother. Simultaneously, the motor speed feedback is adjusted to the boom slewing speed feedback, effectively changing the inverter's control object from the motor to directly controlling the boom. Therefore, the above methods result in smoother slewing.

[0066] Further, please refer to Figure 2 , Figure 2 To provide a second embodiment of the rotation control method of this application based on the first embodiment, in this embodiment, step S10 further includes:

[0067] Step S11: Obtain the current command speed, motor speed, and boom rotation speed;

[0068] Step S30 includes:

[0069] Step S31: Based on the current boom slewing speed, correction command speed, and motor speed, obtain the current estimated tower deformation angle and the current theoretical tower deformation angle.

[0070] Step S32: Adjust the motor speed based on the estimated angle of the current tower deformation and the theoretical angle of the current tower deformation.

[0071] In this embodiment, before adjusting the motor speed, the frequency converter also acquires the current motor speed. Based on the current boom slewing speed, the correction command speed, and the motor speed, it obtains the current estimated tower deformation angle and the current theoretical tower deformation angle. The acquired estimated tower deformation angle and the acquired theoretical tower deformation angle are compared, and the motor speed is adjusted so that the estimated tower deformation angle follows the theoretical tower deformation angle, thereby ensuring that the actual boom slewing speed follows the correction command speed.

[0072] Specifically, step S31 includes:

[0073] Step S311: Obtain the current estimated tower deformation angle based on the preset tower deformation angle estimation module and the current boom rotation speed and motor speed.

[0074] Step S312: Based on the current correction command speed and boom slewing speed, obtain the current theoretical angle of tower deformation.

[0075] The frequency converter inputs the current boom slewing speed and motor speed to the preset tower deformation angle estimation module to obtain the current estimated tower deformation angle. The preset tower deformation angle estimation module is as follows:

[0076]

[0077] in, To estimate the angle of tower deformation, r1 is the radius of the small gear of the slewing mechanism, r2 is the radius of the large gear of the slewing mechanism, K1 is the reduction ratio of the reducer of the slewing mechanism, and ω d Let ω be the rotational speed of the boom. m This refers to the motor's operating speed.

[0078] The theoretical angle of tower deformation is calculated based on the difference between the current correction command speed and the boom slewing speed. The calculation process can be achieved through PID operation, which will not be described in detail here.

[0079] Furthermore, step S31 also includes:

[0080] Step S311: Obtain the current estimated tower deformation angle based on the preset tower deformation angle estimation module and the current boom rotation speed and motor speed.

[0081] Step S314: Based on the current tower deformation estimated angle and the first preset tower deformation theoretical angle calculation model, obtain the current tower deformation theoretical angle.

[0082] The frequency converter inputs the current boom slewing speed and motor speed to the preset tower deformation angle estimation module to obtain the current estimated tower deformation angle. The preset tower deformation angle estimation module is as follows:

[0083]

[0084] in, To estimate the angle of tower deformation, r1 is the radius of the small gear of the slewing mechanism, r2 is the radius of the large gear of the slewing mechanism, K1 is the reduction ratio of the reducer of the slewing mechanism, and ω d Let ω be the rotational speed of the boom. m This refers to the motor's operating speed.

[0085] The frequency converter inputs the current estimated tower deformation angle into the first preset theoretical tower deformation angle calculation model to obtain the current theoretical tower deformation angle. The first preset theoretical tower deformation angle calculation model is as follows:

[0086]

[0087] in, From the perspective of tower deformation theory, K f K is the rotational damping coefficient. t To improve the torsional stiffness of the tower, Estimate the angle for tower deformation.

[0088] Furthermore, step S31 also includes:

[0089] Step S311: Obtain the current estimated tower deformation angle based on the preset tower deformation angle estimation module and the current boom rotation speed and motor speed.

[0090] Step S315: Based on the current tower deformation estimation angle and the second preset tower deformation theoretical angle calculation model, obtain the current tower deformation theoretical angle.

[0091] The frequency converter inputs the current boom slewing speed and motor speed to the preset tower deformation angle estimation module to obtain the current estimated tower deformation angle. The preset tower deformation angle estimation module is as follows:

[0092]

[0093] in, To estimate the angle of tower deformation, r1 is the radius of the small gear of the slewing mechanism, r2 is the radius of the large gear of the slewing mechanism, K1 is the reduction ratio of the reducer of the slewing mechanism, and ω d Let ω be the rotational speed of the boom. m This refers to the motor's operating speed.

[0094] The frequency converter inputs the current estimated tower deformation angle into the second preset theoretical tower deformation angle calculation model to obtain the current theoretical tower deformation angle. The second preset theoretical tower deformation angle calculation model is as follows:

[0095]

[0096] in, From the perspective of the tower deformation theory, T e K represents the electromagnetic torque of the motor. t To improve the torsional stiffness of the tower, The angle is estimated for the tower body deformation. r2 is the radius of the large gear in the tower crane jib drive gear in the tower crane slewing mechanism, r1 is the radius of the small gear in the tower crane jib drive gear in the tower crane slewing mechanism, and K1 is the reduction ratio of the reducer in the tower crane slewing mechanism.

[0097] Since the force on the boom rotation comes from the tower deformation, this embodiment directly uses the tower deformation angle as feedback to adjust the motor speed. Compared with using the boom rotation speed as feedback, this solution makes the rotation control smoother.

[0098] Furthermore, based on the first and second embodiments of the slewing control method of this application, a third embodiment of the slewing control method of this application is proposed. In this embodiment, the method further includes the following step before step S30:

[0099] Step S60: Obtain the target speed;

[0100] Step S70: Determine whether the preset conditions are met based on the target speed and the current correction command speed; if the preset conditions are met, proceed to step S30; if the preset conditions are not met, proceed to step S31.

[0101] In this embodiment, the target speed refers to the stable slewing speed that the boom needs to achieve. For example, when the tower crane operator shifts gears from first to second gear, the target speed refers to the boom slewing speed corresponding to second gear. Before adjusting the motor speed, based on the target speed and the current correction command speed, it is determined whether preset conditions are met. For example, if the difference between the target speed and the current correction command speed is greater than or equal to a preset threshold, the condition is met; if the difference is less than the preset threshold, the condition is not met. If the preset conditions are met, the current boom slewing speed is directly used as feedback to further adjust the correction command speed. For example, a PID control method is used to adjust the correction command speed to obtain the adjusted motor speed command. If the preset conditions are not met, the current estimated tower deformation angle is obtained based on the preset tower deformation angle estimation module, the current boom slewing speed, and the motor speed. Based on the current estimated tower deformation angle and the second preset theoretical tower deformation angle calculation model, the current theoretical tower deformation angle is obtained, thus directly using the tower deformation angle as feedback to adjust the motor speed.

[0102] Compared to using the tower deformation angle as the feedback quantity, the scheme using the boom rotation speed as the feedback quantity has lower latency, but poor stability when approaching the target speed. This embodiment adjusts the motor speed by using different feedback quantities at different stages, which can achieve both low latency and stable operation.

[0103] The present invention also proposes a computer-readable storage medium storing a computer program thereon. The computer-readable storage medium may be a memory in a tower crane, or at least one of ROM (Read-Only Memory) / RAM (Random Access Memory), magnetic disk, and optical disk. The computer-readable storage medium includes several pieces of information to cause the tower crane to perform the methods described in the various embodiments of the present invention.

[0104] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. 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 system that includes that element.

[0105] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0106] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method.

[0107] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A slewing control method, characterized in that, A slewing mechanism is applied to a tower crane, the tower crane including a frequency converter, a motor, a reducer and a slewing mechanism, the frequency converter is connected to the motor, the motor is connected to the reducer, the reducer is used to drive the tower crane boom in the slewing mechanism to rotate, the motor is used to drive the reducer to rotate, and the frequency converter is used to obtain the current command speed of the motor; The slewing control method includes the following steps: Step S10: Obtain the current command speed and boom rotation speed; Step S10 further includes: obtaining the current motor speed; Step S20: Correct the current instruction speed according to the preset correction model to obtain the current corrected instruction speed; Step S30: Adjust the motor speed according to the current boom rotation speed and the correction command speed; Step S31: Based on the current boom slewing speed, correction command speed, and motor speed, obtain the current estimated tower deformation angle and the current theoretical tower deformation angle. Step S32: Adjust the motor speed based on the estimated angle of the current tower deformation and the theoretical angle of the current tower deformation; Before step S30, the method further includes: acquiring a target speed; determining whether a preset condition is met based on the target speed and the current correction command speed; wherein the preset condition includes: if the difference between the target speed and the current correction command speed is greater than or equal to a preset threshold, then the preset condition is met; if the difference between the target speed and the current correction command speed is less than the preset threshold, then the preset condition is not met; if the preset condition is met, then step S30 is executed; if the preset condition is not met, then step S31 is executed. Step S40: Control the motor to run according to the adjusted motor speed.

2. The slewing control method according to claim 1, characterized in that, The step of obtaining the current boom rotation speed includes: Get the current motor speed; The boom rotation speed is obtained based on the current motor speed and the preset boom rotation speed estimation model.

3. The slewing control method according to claim 1, characterized in that, The step of obtaining the current boom rotation speed also includes: Acquire the current boom rotation speed sent by the speed sensor.

4. The slewing control method according to claim 1, characterized in that, The steps of controlling the motor operation based on the adjusted motor speed include: Based on the adjusted motor speed, corresponding output frequency and voltage control signals are generated to control the motor operation.

5. The slewing control method according to claim 1, characterized in that, The steps for obtaining the current estimated tower deformation angle and the current theoretical tower deformation angle based on the current boom rotation speed, correction command speed, and motor speed include: Based on the preset tower deformation angle estimation module and the current boom rotation speed and motor speed, the current tower deformation estimated angle is obtained. Based on the current correction command speed and boom slewing speed, the current theoretical angle of tower deformation is obtained.

6. The slewing control method according to claim 1, characterized in that, The steps for obtaining the current estimated tower deformation angle and the current theoretical tower deformation angle based on the current boom rotation speed, correction command speed, and motor speed include: Based on the preset tower deformation angle estimation module and the current boom rotation speed and motor speed, the current tower deformation estimated angle is obtained. Based on the current estimated angle of tower deformation and the calculation model of the first preset theoretical angle of tower deformation, the current theoretical angle of tower deformation is obtained.

7. The slewing control method according to claim 1, characterized in that, The steps for obtaining the current estimated tower deformation angle and the current theoretical tower deformation angle based on the current boom rotation speed, correction command speed, and motor speed include: Based on the preset tower deformation angle estimation module and the current boom rotation speed and motor speed, the current tower deformation estimated angle is obtained. Based on the current tower deformation estimation angle and the second preset tower deformation theoretical angle calculation model, the current tower deformation theoretical angle is obtained.

8. A tower crane, characterized in that, The tower crane includes a motor, a speed reducer, a frequency converter, a processor, and a computer program stored in a memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the slewing control method as described in any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the slewing control method as described in any one of claims 1 to 7.

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