Control method and control device of lifting system

Abstract

The invention provides a control method and device of a lifting system, and belongs to the technical field of maritime work platform lifting. The control method comprises the steps that the actual rotating speeds and loads of a main motor and slave motors on each pile leg are determined, the main motor is any one of multiple variable frequency motors in the pile leg, and the slave motors are all the variable frequency motors except the main motor; for any pile leg, the actual rotating speed of each slave motor is adjusted according to the actual rotating speed of the main motor, the actual rotating speed of each slave motor, the load of the main motor and the load of each slave motor, so that the actual rotating speed of each slave motor is synchronous with the actual rotating speed of the main motor; the load of the slave motor is synchronous with the load of the master motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of offshore platform lifting, and in particular relates to a control method and a control device for a lifting system. Background Art

[0002] The rack and pinion lifting system for offshore platforms is currently a widely used offshore platform lifting system. Among them, the variable frequency drive rack and pinion lifting system is clean, efficient and easy to maintain, and is increasingly used in the field of lifting systems. Multiple lifting units are provided on each leg of the variable frequency drive rack and pinion lifting system. Each lifting unit includes a variable frequency motor, a gearbox and a pinion arranged on the output shaft of the gearbox. The pinion meshes with the rack on the leg, and the variable frequency motor drives the pinion on the output shaft of the gearbox to rotate, thereby driving the leg to be lifted and lowered through the rack. Due to the large tonnage of the offshore platform, the lifting system needs to synchronize the working states of each variable frequency motor when controlling the lifting of the offshore platform.

[0003] In the related art, in order to synchronize the working states of the variable frequency motors on each pile leg, a speed master-slave control mode is mostly adopted for the multiple variable frequency motors corresponding to each pile leg, and one of the variable frequency motors is selected as the master motor, and the other variable frequency motors are slave motors. When the speed difference between the speed of the master motor and the speed of the slave motor exceeds the 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 rotation speed of all variable frequency motors, resulting in a large load deviation between the variable frequency motors, which makes the offshore platform still unstable and has a poor lifting effect. Summary of the invention

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

[0006] The disclosed embodiment provides a control method for a lifting system, wherein each leg of the lifting system is provided with a plurality of lifting units, each of the lifting units comprises a variable frequency motor, and the control method comprises: determining the actual rotation speed and load of a main motor and each slave motor on each leg, wherein the main motor is any one of the plurality of variable frequency motors in the leg, and the slave motor is all the variable frequency motors except the main motor; for any leg, adjusting the actual rotation speed of the main motor and each slave motor according to the theoretical rotation speed of the main motor, the actual rotation speed of the main motor and the actual rotation 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 rotation speed of the slave motor and the actual rotation speed of the main motor are both synchronized with the theoretical rotation speed, and the load of the slave motor and the load of the main motor are both synchronized with the theoretical load.

[0007] In another implementation of the present disclosure, the actual speed of the main motor and each of the slave motors is adjusted 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, including: 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 speed 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 the present disclosure, the calculating the actual speed of the main motor and the speed difference between the actual speed of each of the slave motors and the theoretical speed includes: calculating the actual speed of the main motor and the speed difference between the actual speed of each of the slave motors and the theoretical speed according to the following formula:

[0009]

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

[0011] In another implementation of the present disclosure, the 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] Wherein, 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 the slave motors; Ti represents the load of the main motor or the i-th slave motor; and T0 represents the theoretical load.

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

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

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

[0017]

[0018] Wherein, Ti is the load of the master motor or the i-th slave motor; is 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 the present disclosure, a control device of a lifting system is further provided, wherein each leg of the lifting system is provided with a plurality of lifting units, each of the lifting units includes a variable frequency motor, and the control device includes a determination module and an adjustment module; the determination module is used to determine the actual rotation speed and load of the main motor and each slave motor on each leg, the main motor is any one of the plurality of variable frequency motors in the leg, and the slave motor is all the variable frequency motors except the main motor; for any leg, the actual rotation speed of the main motor and each slave motor is adjusted according to the theoretical rotation speed of the main motor, the actual rotation speed of the main motor and the actual rotation 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 rotation speed of the slave motor and the actual rotation speed of the main motor are both synchronized with the theoretical rotation speed, and the load of the slave motor and the load of the main motor are both synchronized with the theoretical load.

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

[0021] In yet another implementation of the present disclosure, a computer storage medium is provided on which computer instructions are stored. When the computer instructions are executed by a processor, the control method of the lifting system described above is implemented.

[0022] The technical solution provided by the embodiments of the present disclosure has the following beneficial effects:

[0023] Since the control method provided by the embodiment of the present disclosure is to first determine the actual speed and load of the main motor and the slave motor on each pile leg, and then adjust the actual speed of each slave motor and the actual speed of the main motor according to 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, so that the actual speed of the slave motor and the actual speed of the main motor can be synchronized with the theoretical speed, and the load of the slave motor and the load of the main motor can be synchronized with the theoretical load, so that the actual speed and load of each variable frequency motor can be synchronized, and the stability of the lifting system can be improved. In other words, the 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 be compatible with the synchronization and balance of the actual speed and load of the variable frequency motor at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 is a flow chart of a control method of a lifting system provided by an embodiment of the present disclosure;

[0026] Figure 2 is a flow chart of another control method of a lifting system provided by an embodiment of the present disclosure;

[0027] Figure 3 is a structural block diagram of a lifting device provided by an embodiment of the present disclosure;

[0028] Figure 4 It is a structural block diagram of a computer device provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0030] Each leg of the lifting system is provided with a plurality of lifting units, each of which includes a variable frequency motor, a gear box and a pinion gear arranged on the output shaft of the gear box. The variable frequency motor is connected to the input end of the gear box. When the variable frequency motor is started, the pinion gear is driven to rotate through the gear box. After the pinion gear rotates, it will mesh with the rack on the leg, thereby driving the leg to rise and fall.

[0031] The present disclosure provides a control method for a lifting system. Figure 1As shown, the control method includes:

[0032] S101: Determine the actual rotation 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 the disclosed embodiment, the main motor in the variable frequency motor is used to be connected 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 other slave motors, and the main motor is used to issue instructions to other slave motors to transmit the instructions received from the control system to each slave motor, thereby controlling the speed of the slave motors.

[0035] That is to say, in order to simplify the control system, one of the variable frequency motors is electrically connected to the control system of the offshore platform, and the remaining slave motors only need to be electrically connected to the main motor to realize the input of instructions.

[0036] When making adjustments, the control system first inputs a given value to the main motor to control the speed of the main motor, and the main motor receives the given value and synchronously inputs the same given value to the slave motor to control the speed of the slave motor.

[0037] S102: For any pile leg, the actual speeds of the main motor and each slave motor are adjusted according to the theoretical speed of the main motor, the actual speed of the main motor and the actual speeds 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 speeds of the slave motor and the actual speeds of the main motor are synchronized with the theoretical speeds, and the loads of the slave motor and the loads of the main motor are synchronized with the theoretical load.

[0038] Since the control method provided by the embodiment of the present disclosure is to first determine the actual speed and load of the main motor and the slave motor on each pile leg, and then adjust the actual speed of each slave motor and the actual speed of the main motor according to the actual speed of the main motor, the actual speed of each slave motor and the theoretical speed of the main motor, as well as the load of the main motor, the load of each slave motor and the theoretical load, so that the actual speed of the slave motor and the actual speed of the main motor can be synchronized with the theoretical speed, and the load of the slave motor and the load of the main motor can be synchronized with the theoretical load, so that the actual speed and load of each variable frequency motor can be synchronized, and the stability of the lifting system can be improved. In other words, the 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 be compatible with the synchronization and balance of the actual speed and load of the variable frequency motor at the same time.

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

[0040] Load is also used to describe the proportional relationship between the output torque and rated torque of the variable frequency motor, thereby reflecting the load and operating status of the variable frequency motor. For example, when the torque percentage of the motor is close to or reaches 100%, it means that the motor is running at the rated torque. At this time, the motor has a large load, a strong torque output capacity, and a high working efficiency, while 0% means no load. Under the condition of constant power, when the speed of the motor increases, its torque will decrease accordingly; conversely, when the speed decreases, the torque will increase accordingly. Therefore, the load of the motor can be adjusted by changing the speed.

[0041] Figure 2 is a flow chart of another control method of a lifting system provided by an embodiment of the present disclosure, Figure 2 , the control method of the lifting system includes:

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

[0043] In the disclosed embodiment, four pile legs are provided in the offshore platform. Each pile leg is provided with 12 variable frequency motors. The 12 variable frequency motors are arranged in pairs along the length direction of the pile legs, and the two variable frequency motors in each pair are arranged on opposite sides of the pile legs. The third variable frequency motor in the second column and counted from the top to the bottom is used as the main motor, and the rest are slave motors.

[0044] Exemplarily, the actual 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 speed of the output end of the variable frequency motor can be detected in real time by a rotary encoder. The rotary encoder is connected to the output end of the variable frequency motor.

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

[0046] Assume that the speed command value of the controller is V number , the corresponding variable frequency motor has a given speed V ref (also the reference speed, unit: r / mim) 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 expected speed value of the variable frequency motor set by the controller. Ideally, the actual speed of the variable frequency motor should be equal to the given speed. However, due to factors such as load changes, power supply fluctuations, and mechanical losses, the actual speed deviates from the given speed. In other words, the load is closely related to the actual speed of the motor and the given speed.

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

[0051]

[0052] Among them, Ti is the load of the master motor or the i-th slave motor; is 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.

[0053] That is to say, the load of each variable frequency motor can be directly calculated by the above formula. Among them, the theoretical speed and theoretical load are determined according to the load or working condition of the offshore platform.

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

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

[0056] The actual speed of the master motor and the speed difference between the actual speed of each slave motor and the theoretical speed are calculated according to the following formula:

[0057]

[0058] Wherein, ΔVi represents the speed difference between the main 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 main motor or the i-th slave motor, and V0 represents the actual speed of the main motor.

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

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

[0061] The load difference between the master motor load and each slave motor load and the theoretical load is calculated using the following formula:

[0062]

[0063] Wherein, 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 the embodiment of the present 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 the disclosed embodiment, the rotation speed threshold is any value within the range of 0-0.2.

[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 contents:

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

[0069] Among them, ΔVi represents the speed difference between the main motor or the i-th slave motor and the main motor, Vi represents the 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.

[0070] In the disclosed embodiment, when the speed difference ΔVi>0, it means Vi>V0, that is, the actual speed of the main motor or the slave motor is greater than the theoretical speed, and it is necessary to reduce the actual speed of the main motor or the slave motor. Therefore, ΔVi can be reduced on the basis of the current actual speed of the main motor or the slave motor. When the speed difference ΔVi<0, it means Vi<V0, that is, the actual speed of the main motor or the slave motor is less than the theoretical speed, and it is necessary to increase the actual speed of the main motor or the slave motor. Therefore, ΔVi can be increased on the premise of the current actual speed of the main motor or the slave motor.

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

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

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

[0074] Among them, 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.

[0075] Since the pinion needs to rotate toward the rack on the pile leg when the platform is raised or the pile leg is lowered, the pinion rotates from the outside to the inside and gradually meshes with the rack. In this case, the torque of the pinion is in the same direction as the speed. The greater the load of the pinion, the smaller the speed. Correspondingly, the greater the load of the variable frequency motor, the smaller the speed. When the load difference ΔTi>0, it means Ti>T0, that is, the load of the main motor or the slave motor is greater than the theoretical load, so it is necessary to reduce the load of the main motor or the slave motor. At this time, the speed of the slave motor can be increased. That is, when the platform is raised or the pile leg is lowered, the current actual speed of the main motor or the 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 the slave motor is less than the theoretical load, so it is necessary to increase the load of the main motor or the slave motor. At this time, the speed of the main motor or the slave motor can be reduced. That is, when the platform is raised or the pile leg is lowered, the actual speed of the slave motor can be reduced to increase the load.

[0076] On the contrary, when lowering the platform or raising the pile leg, the pinion needs to rotate away from the rack on the pile leg, and the pinion rotates from the inside to the outside and gradually moves away from the rack. In this case, the torque of the pinion is opposite to the speed. The greater the load of the pinion, the greater the speed. Correspondingly, the greater the load of the variable frequency motor, the greater the speed. When the load difference ΔTi>0, it means Ti>T0, that is, the load of the slave motor or the main motor is greater than the theoretical load, so it is necessary to reduce the load of the main motor or the slave motor. At this time, the speed of the main motor or the slave motor can be reduced. That is, when raising the pile leg or lowering the platform, the actual speed of the main motor or the slave motor can be reduced to reduce the load. When the load difference ΔTi<0, it means Ti<T0, that is, the load of the main motor or the slave motor is less than the load of the main motor, so it is necessary to increase the load of the main motor or the slave motor. At this time, the speed of the main motor or the slave motor can be increased. That is, when raising the platform or lowering the pile leg, the current actual speed of the main motor or the 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, that is, there is no need to adjust the actual speed of the i-th slave motor.

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

[0079] That is to say, the above control method couples the load balancing algorithm while performing speed master-slave control. When the load of a certain variable frequency motor is large, the variable frequency motor actively adjusts the speed within a certain range to reduce the load. The greater the load, the more the speed is adjusted, and the more the load is reduced, so that the load of each variable frequency motor is always maintained at a related balanced level. Because the 12 variable frequency motors of each pile leg always maintain speed master-slave control. When the 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 is always maintained at the given speed benchmark, and at this time the load of the variable frequency motor is also balanced.

[0080] On the other hand, the present disclosure also provides a control device for a lifting system, such as Figure 3As shown, the control device 300 includes a determination module 301 and an adjustment module 302 .

[0081] The determination module 301 is used to determine the rotation 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 variable frequency motors except the main motor.

[0082] For any pile 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 mentioned 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 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, adjust the actual speed of the main motor and each 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.

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

[0086] Optionally, the adjustment module 302 is used to calculate the load difference of the master 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 platform raising condition or the pile leg lowering condition, and the load difference ΔTi>0, and 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 platform lowering condition or the pile leg raising condition, and the load difference ΔTi>0, adjust the actual speed of the main motor or the i-th slave motor to Vi=V(1-|ΔTi|), or adjust the actual speed of the i-th slave motor to Vi=V(1+|ΔTi|) when the load difference ΔTi<0; wherein 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: when the control device 300 provided in the above embodiment controls the lifting system, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is 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 embodiment and the control method embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0091] Figure 4 is a structural block diagram of a computer device provided by an embodiment of the present disclosure, such as Figure 4 As shown, the computer device 400 may be a computer, etc. The computer device 400 includes: a processor 401 and a memory 402 .

[0092] The processor 401 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 401 may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). The processor 401 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 401 may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor 401 may also include an AI (Artificial Intelligence) processor, which is used to process computing 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 a high-speed random access memory, and a non-volatile memory, such as one or more disk storage devices, flash memory storage devices. In some embodiments, the non-transitory computer-readable medium in the memory 402 is used to store at least one instruction, which is used to be executed by the processor 401 to implement the control method provided in the embodiment of the present disclosure.

[0094] Those skilled in the art will understand that Figure 4 The structure shown in the figure does not constitute a limitation on the computer device 400, and the computer device 400 may include more or less components than those shown in the figure, or combine some components, or adopt a different arrangement of components.

[0095] The embodiment of the present disclosure also provides a computer storage medium, which stores computer instructions. When the computer instructions stored in the computer-readable storage medium are executed by an electronic device, the electronic device executes the control method of the lifting system provided by the above method embodiment.

[0096] The embodiment of the present 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 of the lifting system provided by the above method embodiment.

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

Claims

1. A control method for a lifting system, characterized in that: Each leg of the lifting system is provided with a plurality of lifting units, each of the lifting units comprises a variable frequency motor, and the control method comprises: Determine the actual rotation 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; For any of the pile legs, the actual speeds of the main motor and each of the slave motors are adjusted according to the theoretical speed of the main motor, the actual speed of the main motor and the actual speeds 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 speeds of the slave motors and the actual speeds of the main motor are synchronized with the theoretical speeds, and the loads of the slave motors and the loads of the main motor are synchronized with the theoretical load.

2. The control method according to claim 1, characterized in that: The actual speeds of the main motor and each of the slave motors are adjusted according to the theoretical speed of the main motor, the actual speed of the main motor and the actual speeds 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, including: Calculating the actual speed of the main motor and the speed difference between the actual speed of each of the slave motors and the theoretical speed, and calculating the load of the main motor and the load difference between each of the slave motors 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, adjust the actual speeds of the master 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.

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

4. The control method according to claim 2, characterized in that: The calculating the load difference between the load of the master motor and the load of each slave motor and the theoretical load includes: The load difference between the load of the master motor and the load of each slave motor and the theoretical load is calculated according to the following formula: Wherein, 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 the slave motors; Ti represents the load of the main motor or the i-th slave motor; and T0 represents the theoretical load.

5. The control method according to claim 2, characterized in that: The adjusting the actual rotation speed of the master motor and each of the slave motors includes: When the speed difference ΔVi>0, the actual speed of the master motor or the i-th slave motor is adjusted to Vi=V(1-|ΔVi|); Alternatively, when the speed difference ΔVi<0, the actual speed of the master motor or the i-th slave motor is adjusted to Vi=V(1+|ΔVi|); Among them, ΔVi represents the speed difference between the main motor or the i-th slave motor and the actual speed, 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.

6. The control method according to claim 5, characterized in that: The adjusting the actual rotation speed of the master motor and each of the slave motors also includes: When the lifting system is in a platform raising condition or a pile leg lowering condition, and 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|), 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 a platform lowering condition or a pile leg raising condition, and 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|), 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|); Among them, 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.

7. The control method according to claim 5, characterized in that: The method further comprises: The load of the slave motor is calculated by the following formula: Wherein, Ti is the load of the master motor or the i-th slave motor; is 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.

8. A control device for a lifting system, characterized in that: Each leg of the lifting system is provided with a plurality of lifting units, each of the lifting units comprises a variable frequency motor, and the control device comprises a determination module and an adjustment module; The determination module is used to determine the actual rotation 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 of the pile legs, the actual speeds of the main motor and each of the slave motors are adjusted according to the theoretical speed of the main motor, the actual speed of the main motor and the actual speeds 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 speeds of the slave motors and the actual speeds of the main motor are synchronized with the theoretical speeds, and the loads of the slave motors and the loads of the main motor are synchronized with the theoretical load.

9. A computer device, characterized in that: The computer device includes a processor and a memory configured to store instructions executable by the processor; the processor is configured to execute the control method of the lifting system according to any one of claims 1 to 7.

10. A computer storage medium having computer instructions stored thereon, characterized in that: When the computer instructions are executed by a processor, the control method of the lifting system according to any one of claims 1 to 7 is implemented.

Images