Control methods and control devices for lifting systems

Abstract

This disclosure provides a control method and control device for a lifting system, belonging to the field of offshore platform lifting technology. The control method includes: determining the actual speed and load of the main motor and each slave motor on each leg, wherein the main motor is any one of a plurality of variable frequency motors in the leg, and the slave motors are all the variable frequency motors except the main motor; for any leg, adjusting the actual speed of each slave motor according to the actual speed of the main motor and the actual speed of each slave motor, as well as the load of the main motor and the load of each slave motor, so that the actual speed of the slave motor is synchronized with the actual speed of the main motor, and the load of the slave motor is synchronized with the load of the main motor.

Description

Technical Field

[0001] This disclosure belongs to the field of offshore platform lifting technology, and specifically relates to a control method and control device for a lifting system. Background Technology

[0002] Rack and pinion lifting systems are widely used in offshore platforms. Among them, variable frequency drive (VFD) rack and pinion systems are increasingly used due to their cleanliness, efficiency, and ease of maintenance. Each leg of a VFD rack and pinion lifting system has multiple lifting units. Each lifting unit includes a VFD motor, a gearbox, and a pinion mounted on the gearbox output shaft. The pinion meshes with a rack on the leg, and the VFD motor drives the pinion on the gearbox output shaft to rotate, thereby raising or lowering the leg via the rack. Because offshore platforms are relatively large, the lifting system requires synchronized operation of all VFD motors during the lifting process.

[0003] In related technologies, to synchronize the working status of the various variable frequency motors on each pile leg, a master-slave speed control method is generally adopted for the multiple variable frequency motors corresponding to each pile leg. One variable frequency motor is selected as the master motor, and the others are slave motors. When the speed difference between the master motor and the slave motor exceeds a speed threshold, the speed of the slave motor is automatically controlled until the speed difference does not exceed the speed threshold.

[0004] However, the above control method only considers the consistency of the speed of all variable frequency motors, which leads to a large load deviation between the various variable frequency motors. This means that the offshore platform may still be unstable and have poor lifting performance. Summary of the Invention

[0005] This disclosure provides a control method and control device for a lifting system, which can improve the lifting stability of offshore platforms. The technical solution is as follows:

[0006] This disclosure provides a control method for a lifting system. Each leg of the lifting system is equipped with multiple lifting units, and each lifting unit includes a variable frequency motor. The control method includes: determining the actual speed and load of the main motor and each slave motor on each leg; the main motor being any one of the multiple variable frequency motors on the leg, and the slave motors being all the variable frequency motors except the main motor; for any leg, adjusting the actual speed of the main motor and each slave motor based on the theoretical speed of the main motor, the actual speed of the main motor, the actual speed of each slave motor, the theoretical load, the load of the main motor, and the load of each slave motor, such that the actual speed of the slave motor and the actual speed of the main motor are synchronized with the theoretical speed, and the load of the slave motor and the load of the main motor are synchronized with the theoretical load.

[0007] In another implementation of this disclosure, adjusting the actual speeds of the main motor and each of the slave motors based on the theoretical speed of the main motor, the actual speed of the main motor, the actual speeds of each of the slave motors, the theoretical load, the load of the main motor, and the load of each of the slave motors includes: calculating the speed difference between the actual speed of the main motor and the actual speed of each of the slave motors and the theoretical speed, and calculating the load difference between the load of the main motor and the load of each of the slave motors and the theoretical load; when the absolute value of the speed difference is greater than a speed threshold, and / or when the absolute value of the load difference is greater than a load threshold, adjusting the actual speeds of the main motor and each of the slave motors until the absolute value of the speed difference is not greater than the speed threshold and the absolute value of the load difference is not greater than the load threshold.

[0008] In another implementation of this disclosure, calculating the speed difference between the actual speed of the master motor and the actual speed of each slave motor and the theoretical speed includes: calculating the speed difference between the actual speed of the master motor and the actual speed of each slave motor and the theoretical speed according to the following formula:

[0009]

[0010] Where ΔVi represents the speed difference between the master motor or the i-th slave motor and the theoretical speed, i≤n; n represents the number of slave motors; Vi represents the actual speed of the master motor or the i-th slave motor; V0 represents the theoretical speed.

[0011] In another implementation of this disclosure, calculating the load difference between the load of the master motor and the load of each slave motor and the theoretical load includes: calculating the load difference between the load of each slave motor and the load of the master motor according to the following formula:

[0012]

[0013] Where ΔTi represents the difference between the main motor or the i-th slave motor and the theoretical load, i≤n; n represents the number of slave motors; Ti represents the load of the i-th slave motor; T0 represents the theoretical load.

[0014] In another implementation of this disclosure, adjusting the actual speed of the master motor and each of the slave motors includes: when the speed difference ΔVi > 0, adjusting the actual speed of the master motor or the i-th slave motor to Vi = V(1-|ΔVi|); or, when the speed difference ΔVi < 0, adjusting the actual speed of the master motor or the i-th slave motor to Vi = V(1+|ΔVi|); where ΔVi represents the speed difference between the master motor or the i-th slave motor and the actual speed, Vi represents the actual speed of the master motor or the i-th slave motor, and V represents the current actual speed of the master motor or the i-th slave motor.

[0015] In another implementation of this disclosure, adjusting the actual speed of the main motor and each of the slave motors further includes: when the lifting system is in the platform raising or pile leg lowering mode, and the load difference ΔTi > 0, adjusting the actual speed of the i-th slave motor to Vi = V(1 + |ΔTi|), or when the load difference ΔTi < 0, adjusting the actual speed of the i-th slave motor to Vi = V(1 - |ΔTi|); when the lifting system is in the platform lowering or pile leg raising mode, and the load difference ΔTi > 0, adjusting the actual speed of the i-th slave motor to Vi = V(1 - |ΔTi|), or when the load difference ΔTi < 0, adjusting the actual speed of the i-th slave motor to Vi = V(1 + |ΔTi|); where ΔTi represents the load difference between the main motor or the i-th slave motor and the theoretical load, Vi represents the actual speed of the main motor or the i-th slave motor, and V represents the current actual speed of the main motor or the i-th slave motor.

[0016] In another implementation of this disclosure, the method further includes: calculating the load of the slave motor using the following formula:

[0017]

[0018] Where Ti is the load of the main motor or the i-th slave motor; The given speed of the master motor or the i-th slave motor; is the actual speed of the master motor or the i-th slave motor; r is the droop coefficient.

[0019] In another implementation of this disclosure, a control device for a lifting system is also provided. Each leg of the lifting system is equipped with multiple lifting units, and each lifting unit includes a variable frequency motor. The control device includes a determining module and an adjusting module. The determining module is used to determine the actual speed and load of the main motor and each slave motor on each leg. The main motor is any one of the multiple variable frequency motors in the leg, and the slave motors are all the variable frequency motors except the main motor. For any given leg, the actual speed of the main motor and each slave motor is adjusted based on the theoretical speed of the main motor, the actual speed of the main motor, the actual speed of each slave motor, the theoretical load, the load of the main motor, and the load of each slave motor, so that the actual speed of the slave motor and the actual speed of the main motor are synchronized with the theoretical speed, and the load of the slave motor and the load of the main motor are synchronized with the theoretical load.

[0020] In another implementation of this disclosure, a computer device is also provided, the computer device including a processor and a memory configured to store processor-executable instructions; the processor is configured to execute the control method of the lifting system described above.

[0021] In another implementation of this disclosure, a computer storage medium is also provided, on which computer instructions are stored, which, when executed by a processor, implement the control method of the lifting system described above.

[0022] The beneficial effects of the technical solutions provided in this disclosure are:

[0023] The control method provided in this embodiment first determines the actual speed and load of the main motor and slave motor on each pile leg. Then, based on the actual speed of the main motor, the actual speed and theoretical speed of each slave motor, and the load of the main motor, the load of each slave motor, and the theoretical load, the actual speed of each slave motor and the actual speed of the main motor are adjusted so that the actual speed of the slave motor and the actual speed of the main motor are synchronized with the theoretical speed, and the load of the slave motor and the load of the main motor are synchronized with the theoretical load. This allows the actual speed and load of each variable frequency motor to be synchronized, improving the stability of the lifting system. In other words, this control method can not only synchronize the actual speed of each variable frequency motor, but also synchronize the load of each variable frequency motor, and can simultaneously achieve a balanced synchronization of the actual speed and load of the variable frequency motors. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of a control method for a lifting system provided in an embodiment of this disclosure;

[0026] Figure 2 This is a flowchart of another control method for a lifting system provided in this embodiment;

[0027] Figure 3 This is a structural block diagram of a lifting device provided in an embodiment of this disclosure;

[0028] Figure 4 This is a structural block diagram of a computer device provided in an embodiment of this disclosure. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0030] Each leg of the lifting system is equipped with multiple lifting units. Each lifting unit includes a variable frequency motor, a gearbox, and a pinion gear mounted on the output shaft of the gearbox. The variable frequency motor is connected to the input end of the gearbox. When the variable frequency motor starts, it drives the pinion gear to rotate through the gearbox. The rotating pinion gear then meshes with the rack on the leg, thereby raising or lowering the leg.

[0031] This disclosure provides a control method for a lifting system, such as... Figure 1As shown, the control methods include:

[0032] S101: Determine the actual speed and load of the main motor and each slave motor on each pile leg.

[0033] The main motor is any one of the multiple variable frequency motors in the pile leg, and the slave motors are all the variable frequency motors except the main motor.

[0034] In this embodiment of the disclosure, the main motor in the variable frequency motor is connected to the control system, which inputs commands to the main motor to control its speed. The main motor is electrically connected to other slave motors, which send commands to these slave motors, transmitting the received commands from the control system to each slave motor, thereby controlling the speed of the slave motors.

[0035] In other words, to simplify the control system, one of the variable frequency motors is electrically connected to the control system of the offshore platform, while the other slave motors only need to be electrically connected to the main motor to receive commands.

[0036] During adjustment, the control system first inputs a setpoint to the main motor to control its speed. Upon receiving this setpoint, the main motor synchronously inputs the same setpoint to the slave motor to control its speed.

[0037] S102: For any given leg, adjust the actual speed of the main motor and each slave motor according to the theoretical speed of the main motor, the actual speed of the main motor and the actual speed of each slave motor, as well as the theoretical load, the load of the main motor and the load of each slave motor, so that the actual speed of the slave motor and the actual speed of the main motor are synchronized with the theoretical speed, and the load of the slave motor and the load of the main motor are synchronized with the theoretical load.

[0038] The control method provided in this embodiment first determines the actual speed and load of the main motor and slave motor on each pile leg. Then, based on the actual speed of the main motor, the actual speed of each slave motor, the theoretical speed of the main motor, the load of the main motor, the load of each slave motor, and the theoretical load, the actual speed of each slave motor and the actual speed of the main motor are adjusted so that the actual speed of the slave motor and the actual speed of the main motor are synchronized with the theoretical speed, and the load of the slave motor and the load of the main motor are synchronized with the theoretical load. This allows the actual speed and load of each variable frequency motor to be synchronized, improving the stability of the lifting system. In other words, this control method can not only synchronize the actual speed of each variable frequency motor, but also synchronize the load of each variable frequency motor, and can simultaneously achieve a balanced synchronization of the actual speed and load of the variable frequency motors.

[0039] In this embodiment of the disclosure, the load of the variable frequency motor refers to the mechanical load experienced by the variable frequency motor during operation, including inertial load, frictional load, and other loads. It is the resistance or demand generated by the mechanical load on the motor, and is usually expressed as a percentage.

[0040] Load also describes the ratio between the output torque and rated torque of a variable frequency motor, thus reflecting the motor's load condition and operating status. For example, when the motor's torque percentage is close to or reaches 100%, it indicates that the motor is operating at its rated torque. At this time, the motor has a large load, strong torque output capability, and high working efficiency, while 0% indicates no load. With a fixed power, as the motor speed increases, its torque will decrease accordingly; conversely, as the speed decreases, the torque will increase accordingly. Therefore, the motor load can be adjusted by changing the speed.

[0041] Figure 2 This is a flowchart of another control method for a lifting system provided in this disclosure embodiment, combined with... Figure 2 The control methods for the lifting system include:

[0042] S201: Determine the actual speed and load of the main motor and each slave motor on each pile leg.

[0043] In this embodiment, the offshore platform has four legs. Each leg has 12 variable frequency motors. The 12 variable frequency motors are arranged in multiple pairs along the length of the leg, with two motors in each pair located on opposite sides of the leg. The third variable frequency motor in the second column from top to bottom is designated as the master motor, and the rest are slave motors.

[0044] For example, the actual rotational speed of each variable frequency motor on each pile leg can be recorded as Vi. i is any natural number from 1 to 12 (12 represents 12 variable frequency motors). The actual rotational speed at the output of the variable frequency motor can be detected in real time using a rotary encoder connected to the output of the variable frequency motor.

[0045] Since the variable frequency motor is automatically controlled by the controller, the controller can input different speed command values ​​into the variable frequency motor, thereby changing the input current of the variable frequency motor and thus changing the given speed of the variable frequency motor.

[0046] Assume the speed command value of the controller is V. number The corresponding given speed V of the variable frequency motor ref (Also a reference speed, in r / min) is:

[0047]

[0048] According to the above formula (1), when the speed command value of the controller is 20000, the corresponding reference speed of the variable frequency motor is 2500r / min.

[0049] The given speed is the desired speed value of the variable frequency motor set by the controller. Ideally, the actual speed of the variable frequency motor should equal the given speed. However, due to factors such as load changes, power fluctuations, and mechanical losses, the actual speed deviates from the given speed. That is, the load is closely related to both the actual speed and the given speed of the motor.

[0050] In this embodiment of the disclosure, since the load is closely related to the actual speed of the motor and the given speed, the load of each slave motor and the master motor can be calculated according to the following empirical formula (2).

[0051]

[0052] Where Ti is the load of the master motor or the i-th slave motor; The given speed of the master motor or the i-th slave motor; The actual speed of the master motor or the i-th slave motor; r is the droop coefficient.

[0053] In other words, the load of each variable frequency motor can be directly calculated using the above formula. The theoretical speed and theoretical load are determined based on the load or operating conditions of the offshore platform.

[0054] In this embodiment of the disclosure, r is 0.03.

[0055] S202: Calculate the actual speed of the main motor and the speed difference between the actual speed and the theoretical speed of each slave motor.

[0056] The actual speed of the main motor and the speed difference between the actual speed and the theoretical speed of each slave motor are calculated using the following formulas:

[0057]

[0058] Where ΔVi represents the speed difference between the master motor or the i-th slave motor and the theoretical speed, i≤n, n represents the number of slave motors, Vi represents the actual speed of the master motor or the i-th slave motor, and V0 represents the actual speed of the master motor.

[0059] In this embodiment of the disclosure, after the encoder obtains the actual speed of each variable frequency motor, the speed difference between each slave motor and the master motor can be calculated by formula (3).

[0060] S203: Calculate the load difference between the main motor load and the theoretical load for each slave motor.

[0061] Calculate the load difference between the main motor load and the theoretical load for each slave motor using the following formula:

[0062]

[0063] Where ΔTi represents the load difference between the i-th slave motor and the master motor, i≤n; n represents the number of slave motors; Ti represents the load of the i-th slave motor; and T0 represents the load of the master motor.

[0064] In this embodiment of the disclosure, after the load of each slave motor and the master motor is calculated according to formula (2), the load difference between each slave motor and the master motor can be calculated by formula (4).

[0065] In this embodiment of the disclosure, the rotational speed threshold is any value between 0 and 0.2.

[0066] S204: When the absolute value of the speed difference is greater than the speed threshold, and / or when the absolute value of the load difference is greater than the load threshold, adjust the actual speed of the main motor or the slave motor until the absolute value of the speed difference is not greater than the speed threshold and the absolute value of the load difference is not greater than the load threshold.

[0067] Optionally, step S204 includes the following:

[0068] 2041: When the speed difference ΔVi > 0, adjust the actual speed of the i-th slave motor to Vi = V(1 - |ΔVi|), and when the speed difference ΔVi < 0, adjust the actual speed of the i-th slave motor to Vi = V(1 + |ΔVi|).

[0069] Where ΔVi represents the speed difference between the master motor or the i-th slave motor and the master motor, Vi represents the speed of the master motor or the i-th slave motor, and V represents the current actual speed of the master motor or the i-th slave motor.

[0070] In this embodiment of the disclosure, when the speed difference ΔVi > 0, it indicates that Vi > V0, meaning the actual speed of the master motor or slave motor is greater than the theoretical speed. Therefore, the actual speed of the master motor or slave motor needs to be reduced. Thus, ΔVi can be reduced based on the current actual speed of the master motor or slave motor. When the speed difference ΔVi < 0, it indicates that Vi < V0, meaning the actual speed of the master motor or slave motor is less than the theoretical speed. Therefore, the actual speed of the master motor or slave motor needs to be increased. Thus, ΔVi can be increased based on the current actual speed of the master motor or slave motor.

[0071] When ΔVi = 0, the actual speed of the main motor or the i-th slave motor remains unchanged.

[0072] 2042: When the lifting system is in the lifting platform condition or the lowering leg condition, and the load difference ΔTi>0, adjust the speed of the i-th slave motor to Vi=V(1+|ΔTi|), and when the load difference ΔTi<0, adjust the speed of the i-th slave motor to Vi=V(1-|ΔTi|).

[0073] Alternatively, when the lifting system is in the lowering platform condition or the raising leg condition, and the load difference ΔTi > 0, adjust the speed of the i-th slave motor to Vi = V(1-|ΔTi|), or when the load difference ΔTi < 0, adjust the speed of the i-th drive to Vi = V(1+|ΔTi|).

[0074] Where ΔTi represents the load difference between the master motor or the i-th slave motor and the theoretical load, Vi represents the actual speed of the master motor or the i-th slave motor, and V represents the current actual speed of the master motor or the i-th slave motor.

[0075] When raising the platform or lowering the pile legs, the pinion gear needs to rotate towards the rack on the pile leg. The pinion gear rotates from the outside in and gradually meshes with the rack. In this case, the torque and rotational speed of the pinion gear are in the same direction. The greater the load on the pinion gear, the lower its rotational speed. Correspondingly, the greater the load on the variable frequency motor, the lower its rotational speed. When the load difference ΔTi > 0, it means Ti > T0, that is, the load of the main motor or slave motor is greater than the theoretical load. Therefore, it is necessary to reduce the load on the main motor or slave motor. This can be done by increasing the speed of the slave motor. That is, when raising the platform or lowering the pile legs, the actual current speed of the main motor or slave motor can be increased to reduce the load. When the load difference ΔTi < 0, it means Ti < T0, that is, the load of the main motor or slave motor is less than the theoretical load. Therefore, it is necessary to increase the load on the main motor or slave motor. This can be done by decreasing the speed of the main motor or slave motor. That is, when raising the platform or lowering the pile legs, the actual speed of the slave motor can be decreased to increase the load.

[0076] Conversely, when lowering the platform or raising the legs, the pinion needs to rotate away from the rack on the legs. The pinion rotates from the inside out, gradually moving away from the rack. In this case, the torque and rotational speed of the pinion are opposite. The greater the load on the pinion, the higher its rotational speed. Correspondingly, the greater the load on the variable frequency motor, the higher its rotational speed. When the load difference ΔTi > 0, it means Ti > T0, that is, the load on the slave motor or main motor is greater than the theoretical load. Therefore, the load on the main motor or slave motor needs to be reduced. This can be done by reducing the rotational speed of the main motor or slave motor. In other words, when raising the legs or lowering the platform, the actual rotational speed of the main motor or slave motor can be reduced to decrease the load. When the load difference ΔTi < 0, it means Ti < T0, that is, the load on the main motor or slave motor is less than the load on the main motor. Therefore, the load on the main motor or slave motor needs to be increased. This can be done by increasing the rotational speed of the main motor or slave motor. In other words, when raising the platform or lowering the legs, the current actual rotational speed of the main motor or slave motor can be increased to increase the load.

[0077] When ΔTi = 0, the load of the slave motor is equal to the load of the master motor, meaning there is no need to adjust the actual speed of the i-th slave motor.

[0078] In this embodiment, the above control method is used to control the platform of a lifting system. According to the platform weight and speed control requirements of this embodiment, the controller sets the speed command value of the slave motor in a certain leg to 7960. At this time, according to Formula 1, the given speed of the motor is 995 r / min. Then, the encoder detects the actual speed of the slave motor as 980 r / min. According to Formula 2, the load of the slave motor is calculated to be 48%. The load of the master motor is also 48%. It can be seen that the above control method can not only ensure the consistency of speed among the slave motors, but also achieve good load consistency. This control strategy is effective and meets the requirements of engineering applications.

[0079] In other words, the above control method couples a load balancing algorithm to the speed master-slave control. When the load on a certain variable frequency motor is large, the motor actively adjusts its speed within a certain range to reduce the load. The larger the load, the more the speed is adjusted, and the greater the load reduction, thus always keeping the load of each variable frequency motor at a relatively balanced level. Because the 12 variable frequency motors on each pile leg always maintain speed master-slave control, when a variable frequency motor with a large load decelerates, in order to maintain the speed master-slave control strategy, the decelerated variable frequency motor will immediately accelerate, and the speed of the variable frequency motor will always be maintained at the given speed benchmark. At this time, the load of the variable frequency motor is also balanced.

[0080] On the other hand, embodiments of this disclosure also provide a control device for a lifting system, such as... Figure 3As shown, the control device 300 includes a determining module 301 and an adjusting module 302.

[0081] The determination module 301 is used to determine the speed and load of the main motor and each slave motor on each pile leg. The main motor is any one of the multiple variable frequency motors in the pile leg, and the slave motors are all the variable frequency motors except the main motor.

[0082] For any given leg, the adjustment module 302 is used to adjust the actual speed of the main motor and each slave motor according to the theoretical speed of the main motor, the actual speed of the main motor and the actual speed of each slave motor, as well as the theoretical load, the load of the main motor and the load of each slave motor, so that the actual speed of the slave motor and the actual speed of the main motor are synchronized with the theoretical speed, and the load of the slave motor and the load of the main motor are synchronized with the theoretical load.

[0083] The control device has the same beneficial effects as the control method described above, and will not be described in detail here.

[0084] Optionally, the adjustment module 302 is used to calculate the actual speed of the main motor and the speed difference between the actual speed of each slave motor and the theoretical speed, and to calculate the load of the main motor and the load difference between the load of each slave motor and the theoretical load; when the absolute value of the speed difference is greater than the speed threshold, and / or when the absolute value of the load difference is greater than the load threshold, the actual speed of the main motor and each slave motor is adjusted until the absolute value of the speed difference is not greater than the speed threshold and the absolute value of the load difference is not greater than the load threshold.

[0085] Optionally, the adjustment module 302 is used to calculate the speed difference between the master motor or each slave motor according to formula (3).

[0086] Optionally, the adjustment module 302 is used to calculate the load difference of the main motor or each slave motor according to formula (4).

[0087] Optionally, the adjustment module 302 is used to adjust the actual speed of the i-th master motor or slave motor to Vi = V(1-|ΔVi|) when the speed difference ΔVi > 0, or to adjust the actual speed of the master motor or the i-th slave motor to Vi = V(1+|ΔVi|) when the speed difference ΔVi < 0.

[0088] Optionally, the adjustment module 302 is used to adjust the actual speed of the main motor or the i-th slave motor to Vi = V(1 + |ΔTi|) when the lifting system is in the lifting platform operation mode or the lowering pile leg operation mode, and the load difference ΔTi > 0, and to adjust the actual speed of the i-th slave motor to Vi = V(1 - |ΔTi|) when the load difference ΔTi < 0; when the lifting system is in the lowering platform operation mode or the lifting pile leg operation mode, and the load difference ΔTi > 0, to adjust the actual speed of the main motor or the i-th slave motor to Vi = V(1 - |ΔTi|), or to adjust the actual speed of the i-th slave motor to Vi = V(1 + |ΔTi|) when the load difference ΔTi < 0; where ΔTi represents the load difference between the main motor or the i-th slave motor and the theoretical load, Vi represents the actual speed of the main motor or the i-th slave motor, and V represents the current actual speed of the main motor or the i-th slave motor.

[0089] Optionally, the determination module 301 is used to calculate the load of the master motor or each slave motor according to formula (2).

[0090] It should be noted that the control device 300 provided in the above embodiments is only illustrated by the division of the above functional modules when controlling the lifting system. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the equipment can be divided into different functional modules to complete all or part of the functions described above. In addition, the control device 300 provided in the above embodiments and the control method embodiments belong to the same concept, and its specific implementation process can be found in the method embodiments, which will not be repeated here.

[0091] Figure 4 This is a structural block diagram of a computer device provided in an embodiment of this disclosure, such as... Figure 4 As shown, the computer device 400 can be a computer or the like. The computer device 400 includes a processor 401 and a memory 402.

[0092] Processor 401 may include one or more processing cores, such as a quad-core processor, an octa-core processor, etc. Processor 401 may be implemented using at least one hardware form selected from DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). Processor 401 may also include a main processor and a coprocessor. The main processor, also known as a CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, processor 401 may integrate a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, processor 401 may also include an AI (Artificial Intelligence) processor, which is used to handle computational operations related to machine learning.

[0093] The memory 402 may include one or more computer-readable media, which may be non-transitory. The memory 402 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In some embodiments, the non-transitory computer-readable media in the memory 402 is used to store at least one instruction, which is executed by the processor 401 to implement the control method provided in the embodiments of this disclosure.

[0094] Those skilled in the art will understand that Figure 4 The structure shown does not constitute a limitation on computer device 400, and may include more or fewer components than shown, or combine certain components, or use different component arrangements.

[0095] This disclosure also provides a computer storage medium storing computer instructions. When the computer instructions stored in the computer-readable storage medium are executed by an electronic device, the electronic device performs the control method of the lifting system provided in the above-described method embodiments.

[0096] This disclosure also provides a computer program product, which includes one or more computer program instructions. When the computer program instructions are loaded and run by a computer, the computer executes the control method for the lifting system provided in the above-described method embodiments.

[0097] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A control method for a lifting system, characterized in that, Each leg of the lifting system is equipped with multiple lifting units, and each lifting unit includes a variable frequency motor. The control method includes: The actual speed and load of the main motor and each slave motor on each pile leg are determined. The main motor is any one of the multiple variable frequency motors in the pile leg, and the slave motors are all the variable frequency motors except the main motor. The main motor is used to connect to the control system, and the control system is used to input commands to the main motor to control the speed of the main motor. The main motor is electrically connected to each of the slave motors, and the main motor is used to send commands to each of the slave motors to transmit the commands received from the control system to each of the slave motors, thereby controlling the speed of the slave motors. For any of the pile legs, based on the theoretical speed of the main motor, the actual speed of the main motor, the actual speed of each of the slave motors, the theoretical load, the load of the main motor, and the load of each of the slave motors, the actual speed of the main motor and the actual speed of the slave motors are adjusted so that the actual speed of the slave motors and the actual speed of the main motor are synchronized with the theoretical speed, and the load of the slave motors and the load of the main motor are synchronized with the theoretical load. The adjustment of the actual speed of the main motor and each of the slave motors includes: Calculate the actual speed of the main motor and the speed difference between the actual speed of each slave motor and the theoretical speed, and calculate the actual load of the main motor and the load difference between the actual load of each slave motor and the theoretical load. When the speed difference ΔVi > 0 between the master motor and the i-th slave motor, the actual speed of the master motor or the i-th slave motor is adjusted to Vi = V(1-|ΔVi|). When the speed difference ΔVi of the master motor or the i-th slave motor is less than 0, the actual speed of the master motor or the i-th slave motor is adjusted to Vi = V(1 + |ΔVi|). Wherein, ΔVi represents the speed difference between the master motor or the i-th slave motor and the actual speed, Vi represents the modified actual speed of the master motor or the i-th slave motor, and V represents the current actual speed of the master motor or the i-th slave motor; When the lifting system is in the lifting platform operation mode or the lowering pile leg operation mode, and the load difference ΔTi > 0 of the main motor or the i-th slave motor, the actual speed of the main motor or the i-th slave motor is adjusted to Vi = V(1 + |ΔTi|), or when the load difference ΔTi < 0, the actual speed of the main motor or the i-th slave motor is adjusted to Vi = V(1 - |ΔTi|). When the lifting system is in the lowering platform mode or the raising leg mode, and the load difference ΔTi > 0 of the main motor or the i-th slave motor, the actual speed of the main motor or the i-th slave motor is adjusted to Vi = V(1-|ΔTi|), or when the load difference ΔTi < 0 of the main motor or the i-th slave motor, the actual speed of the main motor or the i-th slave motor is adjusted to Vi = V(1+|ΔTi|). Wherein, ΔTi represents the load difference between the master motor or the i-th slave motor and the theoretical load, Vi represents the modified actual speed of the master motor or the i-th slave motor, and V represents the current actual speed of the master motor or the i-th slave motor.

2. The control method according to claim 1, characterized in that, The calculation of the actual speed of the main motor and the speed difference between the actual speed of each slave motor and the theoretical speed includes: The actual speed of the main motor and the speed difference between the actual speed and the theoretical speed of each slave motor are calculated according to the following formula: ； Where ΔVi represents the speed difference between the master motor or the i-th slave motor and the theoretical speed, i≤n; n represents the number of slave motors; Vi represents the actual speed of the master motor or the i-th slave motor; V0 represents the theoretical speed.

3. The control method according to claim 1, characterized in that, The calculation of the load difference between the load of the main motor and the load of each slave motor and the theoretical load includes: The load difference between the load of the main motor and the load of each slave motor and the theoretical load is calculated according to the following formula: ； Where ΔTi represents the difference between the main motor or the i-th slave motor and the theoretical load, i≤n; n represents the number of slave motors; Ti represents the load of the main motor or the i-th slave motor; T0 represents the theoretical load.

4. The control method according to claim 1, characterized in that, The method further includes: The load of the slave motor is calculated using the following formula: ； Where Ti is the load of the main motor or the i-th slave motor; The given speed of the master motor or the i-th slave motor; The actual speed of the master motor or the i-th slave motor; This is the droop coefficient.

5. A control device for a lifting system, characterized in that, Each leg of the lifting system is equipped with multiple lifting units, each lifting unit includes a variable frequency motor, and the control device includes a determination module and an adjustment module; The determining module is used to determine the actual speed and load of the main motor and each slave motor on each pile leg. The main motor is any one of the multiple variable frequency motors in the pile leg, and the slave motors are all the variable frequency motors except the main motor. The main motor is used to connect to the control system, and the control system is used to input instructions to the main motor to control the speed of the main motor. The main motor is electrically connected to each of the slave motors, and the main motor is used to send instructions to each of the slave motors to transmit the received instructions from the control system to each of the slave motors, thereby controlling the speed of the slave motors. For any of the pile legs, the adjustment module is used to adjust the actual speed of the main motor and each of the slave motors according to the theoretical speed of the main motor, the actual speed of the main motor and the actual speed of each of the slave motors, as well as the theoretical load, the load of the main motor and the load of each of the slave motors, so that the actual speed of the slave motors and the actual speed of the main motor are synchronized with the theoretical speed, and the load of the slave motors and the load of the main motor are synchronized with the theoretical load; The adjustment module is also used to: calculate the actual speed of the main motor and the speed difference between the actual speed of each slave motor and the theoretical speed, and calculate the actual load of the main motor and the load difference between the actual load of each slave motor and the theoretical load. When the speed difference ΔVi > 0 between the master motor and the i-th slave motor, the actual speed of the master motor or the i-th slave motor is adjusted to Vi = V(1-|ΔVi|). When the speed difference ΔVi of the master motor or the i-th slave motor is less than 0, the actual speed of the master motor or the i-th slave motor is adjusted to Vi = V(1 + |ΔVi|). Wherein, ΔVi represents the speed difference between the master motor or the i-th slave motor and the actual speed, Vi represents the modified actual speed of the master motor or the i-th slave motor, and V represents the current actual speed of the master motor or the i-th slave motor; When the lifting system is in the lifting platform operation mode or the lowering pile leg operation mode, and the load difference ΔTi > 0 of the main motor or the i-th slave motor, the actual speed of the main motor or the i-th slave motor is adjusted to Vi = V(1 + |ΔTi|), or when the load difference ΔTi < 0, the actual speed of the main motor or the i-th slave motor is adjusted to Vi = V(1 - |ΔTi|). When the lifting system is in the lowering platform mode or the raising leg mode, and the load difference ΔTi > 0 of the main motor or the i-th slave motor, the actual speed of the main motor or the i-th slave motor is adjusted to Vi = V(1-|ΔTi|), or when the load difference ΔTi < 0 of the main motor or the i-th slave motor, the actual speed of the main motor or the i-th slave motor is adjusted to Vi = V(1+|ΔTi|). Wherein, ΔTi represents the load difference between the master motor or the i-th slave motor and the theoretical load, Vi represents the modified actual speed of the master motor or the i-th slave motor, and V represents the current actual speed of the master motor or the i-th slave motor.

6. A computer device, characterized in that, The computer device includes a processor and a memory configured to store executable instructions of the processor; the processor is configured to perform the control method of the lifting system according to any one of claims 1-4.

7. A computer storage medium storing computer instructions thereon, characterized in that, When the computer instructions are executed by the processor, they implement the control method of the lifting system according to any one of claims 1-4.

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