Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B66—HOISTING; LIFTING; HAULING
  • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
  • B66C13/00—Other constructional features or details
  • B66C13/18—Control systems or devices
  • B66C13/22—Control systems or devices for electric drives

Definitions

• the present invention relates to an oversized tonnage crane, and more particularly to an electrical control scheme for a multi-point crane for overall docking and manufacturing of offshore drilling platforms.
• the electrical synchronization control of the lifting mechanism is up to 4 lifting points, and the lifting load is uniform load, the wire rope of the reel is single-layer winding, the control method is relatively simple, and the four winping systems can adopt the same speed given signal.
• the external position detection is used to judge whether the lifting heights of the four hoisting systems are out of tolerance. Once the allowable value is exceeded, the additional mechanism of the driving device will be used to make the oversized mechanism follow, and finally the speed of the four sets of hoisting systems is synchronized. Location sync.
• this simple lifting mechanism can not meet the smooth lifting of large-tonnage equipment, so it needs to be hoisted by a large tonnage multi-lifting bridge crane to meet the requirements of large-scale assembly projects such as the overall hoisting drilling platform.
• Types and lifting cranes the design of their electrical control system schemes are not similar.
• the multiple lifting points are not simple hoisting mechanisms. Because of the uneven load, each motor has different output and also requires lifting mechanism.
• the speed of the hoisting system reel can be multi-layered, and the linear speed of each reel is different with respect to the rotation speed of the same motor. The tensile force of the wire rope is different.
• the invention aims at the deficiencies of the prior art, and develops an electric control system for a super-large tonnage multi-point crane with stable system, stable lifting and flexible lifting; the technical means adopted by the invention are as follows:
• An electric control method for a plurality of lifting point cranes characterized in that the method comprises the following steps: a. preparing a mode in which a lifting mechanism participating in the work is selected to detect a high and low voltage power distribution system, a main driving system, After the control system is not faulty, input the estimated weight of the object to be lifted on the host computer, the weight Reference weight as a hover mode;
• each lifting motor adopts torque control.
• the sum of the hook group and the total weight of the mechanical attachment and the weight of the wire rope are multiplied by the correlation coefficient as the inverter torque reference value.
• the motor participating in the operation runs together and runs at a given torque at a low speed.
• the pre-tensioning ends and the motor maintains a given torque.
• the mechanical brake is braked, after all the motors participating in the work are pre-tensioned, the height coordinates of the hoisting mechanisms participating in the work are memorized as the coordinate plane when the hovering mode is leveled;
• each hoisting motor adopts speed control.
• the motor torque limit value is set by the controller.
• the value is the rated lifting capacity of the single mechanism.
• the starting mechanism raises it and participates in the work.
• the motor runs together, and the load is gradually lifted.
• the speed of the inverter is given, and the speed of the wire rope is given.
• the position correction and the target force correction are not enabled. After the load is leveled, the target of each point is determined.
• the load cell After pulling, the load cell transmits the tension value of each mechanism involved in the lifting to the controller, and the controller program calculates the centroid position of the object to be lifted, and then the controller calculates the target pulling force of each lifting point, and the value will be
• the joint lifting mode After used in the joint lifting mode, after the leveling and target tension range are determined, the joint lifting mode can be entered. At this time, the coordinate values and target tension of each working mechanism are memorized by the system for the joint lifting mode; d. Joint lifting mode, enter the joint In the lifting mode, each hoisting motor adopts speed control, and the torque limit of the motor is the same as the hovering mode.
• the speed is given, for the wire rope speed, when the coordinate plane formed by each lifting point is not parallel with the coordinate plane of the memory in the hover mode, and the position correction is performed when the lifting value is exceeded, when a lifting mechanism is used
• the system performs the target force correction.
• the sum of the tensile forces in each group remains unchanged during the correction, and the position correction and the target force correction are corrected by hysteretic comparison. After the plane is parallel, the tension of each lifting point is steadily lifted within the set value range.
• the step b is calculated from the height of the hook point and the unit weight of the wire rope when calculating the weight of the wire rope; and the coefficient is related to the number of wire rope layers of the roll, that is, the actual radius of the roll.
• the step b also includes the step of manually controlling the vehicle to return to the zero position and the mechanical brake immediately braking in the event of an emergency such as a loose rope, a grooving, etc. during the pre-tensioning process.
• the load exceeds the lifting capacity of the bridge machine, or the lifting point is unreasonably arranged, the load of the individual hoisting mechanism exceeds the maximum lifting capacity that can be carried by itself, and the load cannot be lifted or cannot be lifted as a whole.
• the load should be put down, and then check whether the total weight of the load matches the estimated weight in the preparation mode. If there is a large deviation, check the load cell and recalculate the load weight or weight. Newly placed lifting ears.
• the load will need to be leveled.
• the stationary point that is, the lifting mechanism does not move when leveling.
• the current coordinate and the pre-tensioned coordinate difference are used as the leveling reference.
• the current coordinate of the remaining points and the pre-tensioned coordinate difference are measured.
• the rest point is generally the highest coordinate point, and the remaining points are wedge-shaped, except static. The other points outside the point are automatically leveled.
• the speed of the inverter is given as zero, the position correction is additionally enabled, and the target force correction is not enabled.
• the speed limit of the motor is set to full speed, and the load can be artificially controlled to rise and fall, and the speed is 1 : 10 stepless speed regulation.
• the step d further includes the system using the position correction as the first additional reference, and the target force correction as the second additional reference; if the deviation is large, the automatic additional reference cannot be completely corrected, and the manual correction can be manually added.
• the step d further includes: when the lifting mechanism of the lifting device exceeds 110% of the rated pulling force when the lifting mechanism is operated in combination, the weighing sensor sends an alarm signal to the main controller, and all the participating agencies perform the operation.
• the step of braking is not limited to: when the lifting mechanism of the lifting device exceeds 110% of the rated pulling force when the lifting mechanism is operated in combination, the weighing sensor sends an alarm signal to the main controller, and all the participating agencies perform the operation.
• the device adopting the electric control method of the multi-hanging crane includes a hoisting mechanism composed of a frequency converter, an inverter, a communication module and an electric motor, and also includes a controller, a load sensor, a position sensor and a host computer, and the controller is responsible for the same as the upper computer
• the communication receives the control command, returns the on-site information, and simultaneously controls the feedback signals of the hoisting mechanism operation and the receiving sensor; the load sensor and the position sensor transmit the bearing weight and the hoisting height information of each hoisting mechanism to the control through the communication module carried by the hoisting mechanism Adjusting the operation of each lifting mechanism after processing by the controller;
• Controller is
• the load cell is a load cell
• the position sensor is a coded sensor
• the electric control system of the super large tonnage multi-point crane provided by the invention adopts various advanced technologies, detection means and control methods to solve the synchronous control of multi-lift point, large tonnage and multi-layer winding crane.
• the problem can meet the requirements of special lifting process, which will bring significant economic and social benefits.
• FIG. 1 is a schematic diagram of electrical control of the present invention
• 2 is a circuit block diagram of the present invention
• 3 is a connection diagram of an electrical network in an embodiment of the present invention
• Figure 4 is a schematic structural view of a multi-point crane according to the present invention.
• FIG. 5 is a schematic diagram of automatically calculating a centroid position in an embodiment of the present invention.
• FIG. 6 is a schematic diagram of automatically assigning a target tensile force value of each lifting point in an embodiment of the present invention
• controller In the figure: 1, controller, 2, lifting mechanism, 3, load sensor, 4, position sensor, 5, host computer, 6, control unit, 7, sensing unit, 8, execution unit, 9, lifting point, 10. Hoisting system, 11. Main beam, 12. Steering pulley.
• the ultra-large tonnage multi-lift crane provided by the present invention is required to adopt a special mechanical structure to meet the special process requirements of a large non-uniform load such as an overall hoisting drilling platform, that is, the hoisting mechanism is composed of multiple sets of hoisting systems. Among them, there are as many as 24 lifting points 9 on the main beam 11, which are driven by the six hoisting systems 10, so that the crane control system is important for safe and smooth lifting.
• the electrical system of the oversized tonnage multi-hedge crane consists of high and low voltage power supply and distribution systems; hoisting mechanism drive control system; PLC control and management system; signal detection and safety protection system; auxiliary systems for lighting, signal, ventilation and heating; TV monitoring system; communication system, lightning protection and grounding system, etc., as shown in Figure 1 to Figure 3, wherein the lifting and control part mainly includes the lifting of inverter, inverter, communication module and motor.
• the mechanism 2 further includes a controller 1, a load sensor 3, a position sensor 4, and a host computer 5. The controller is responsible for receiving control commands, returning on-site information, and controlling the operation of each hoisting mechanism and receiving the sensor.
• each sensor constitutes a sensing unit 7, a lifting machine Driven by the execution unit 8
• each of the above units includes a communication module connected by a bus communication method, the controller adopts a PLC, and the crane heavy load sensor is mounted under the diverting pulley 12 as a load cell, and the position sensor is a coded sensor installation. On the motor.
• the world's leading reversible AC multi-drive variable frequency speed control system is adopted to achieve precise speed and torque control for each motor.
• the application of parallel operation technology of multiple sets of rectification feedback units is adopted to meet the demand of large-capacity motor power supply and achieve energy saving effect.
• the powerful and high-performance PLC is used as the core control system, integrated industrial Ethernet technology and fieldbus technology. Achieve centralized and decentralized control, making various data collection and calculation stable and fast.
• Control mode is divided into preparation mode, wire rope pretensioning mode, hover mode, joint lifting mode -
• Preparation mode In this mode, the hoisting mechanism participating in the work is selected. After detecting the high and low voltage power distribution system, the main drive system, the PLC system and the like without failure, the estimated weight of the suspended object is input in the upper computer 5 of the control station 6, and the weight is used as the reference weight of the hovering mode. After completing the above work, the wire rope pre-tensioning mode can be entered after human confirmation.
• each lifting motor adopts torque control.
• the coefficient consider the number of layers of the wire rope of the reel, that is, the actual radius of the reel.
• the handle After all the motors participating in the work have been pre-tensioned, pull the handle back to the zero position and press the "pre-tightening end" button on the upper computer screen to enter the hover mode. At this time, the height coordinates of the hoisting mechanisms participating in the work are It is memorized as the coordinate plane when the hover mode is leveled. During the pre-tensioning process, if there is an emergency such as a rope loose rope or a grooving, the handle can be immediately pulled back to the zero position and the mechanical brake is immediately braked.
• an emergency such as a rope loose rope or a grooving
• each hoist motor adopts speed control, and the motor torque limit value is set by the bus. This value is 1.5 times the motor torque at the rated lifting capacity of a single mechanism and the maximum number of layers of the wire rope. Push the handle in the ascending direction, and the motor participating in the operation runs together to gradually lift the load. At this time, the speed limit of the motor is 50% of the rated speed, which is half of the normal speed. At this time, the speed of the inverter is given. After the speed calculation factor is calculated by the wire rope speed, the input inverter, position correction and target force correction are not enabled.
• the load exceeds the lifting capacity of the bridge machine; or the lifting point is unreasonably arranged, the load of the individual lifting points exceeds the maximum lifting capacity of the lifting unit, and the load cannot be lifted or cannot be lifted as a whole. At this point, the load should be lowered and the load weight or the position of the lifting lug should be recalculated. If the load is lifted smoothly, all leave the load. Check whether the total weight of the load matches the estimated weight in the preparation mode. If there is a large deviation, check the load cell and recalculate the load weight. If the system detects that the coordinate plane when hovering is not parallel with the coordinate plane when the wire rope is pre-tensioned, the load will need to be leveled.
• the stationary point is selected, that is, the lifting mechanism does not move when leveling.
• the difference between the current coordinate and the pre-tensioned coordinate is used as the leveling reference, and the current coordinate of the remaining points and the pre-tensioned coordinate difference are measured.
• the stationary point is generally the highest coordinate point, and the remaining points are wedge-shaped.
• the speed of the inverter is given as zero, the position correction is additionally enabled, and the target force is corrected.
• the target tension of each point is determined.
• the load cell transmits the tension value of each mechanism involved in the lifting to the PLC, and the centroid position of the object to be lifted is calculated by the PLC program. Then it is calculated by the PLC. The target pull of each lifting point.
• the centroid of the lifting piece is automatically calculated, and the pulling force of each lifting point is reasonably distributed as shown in Fig. 6.
• the pulling force of the hanging piece in the horizontal state is measured by the tension sensor of each lifting point under the "hovering mode" as shown in Fig. 6.
• the control system will automatically calculate the position of the centroid of the lifting piece according to these values, and automatically assign the target pulling force value to each lifting point in the form of an arithmetic progression (see the distribution tension value), so that it can be guaranteed.
• the lifting force of each lifting point is more reasonable, which can effectively prevent tipping. This value will be used in the joint lifting mode.
• press the "Hover End” button to enter the joint lifting mode.
• the coordinate values and target tension of each working mechanism are memorized by the system for the joint lifting mode.
• the lifting motor adopts speed control, and the speed limit of the motor is set to 100% by the bus.
• the torque limit of the motor is the same as the hover mode.
• the handle can be used to complete the ascending and descending movement of the load, and the 1: 10 stepless speed regulation.
• the speed of the inverter is given, and is calculated by the speed calculation factor of the wire rope speed, and then input to the inverter.
• position correction is performed; when the pulling force of a lifting mechanism is lower than 80% or higher of the target tensile value After 120% of the target tension value, the system performs the target force correction, and the total tension in each group remains unchanged during the correction.
• Both position correction and target force correction use hysteresis comparison to prevent system oscillations.
• the system uses the position correction as the first additional reference, and the target force correction as the second additional reference; if the deviation is large, the automatic additional reference cannot be completely corrected, and the manual correction can be manually added.
• the weighing sensor When the lifting mechanism is operated in combination, after the pulling force of a lifting mechanism exceeds 110% of the rated tensile force, the weighing sensor sends an alarm signal to the PLC, and all the participating mechanisms are braked, and the operation can be continued after the fault is eliminated. .
• the hoisting mechanism wire winding method is multi-layer winding, the hoisting mechanism has different linear velocities at each layer for a certain motor speed.
• the control system cooperates with various external detection means to provide different speed reference signals for the inverter according to different layers, which can ensure the wire speed of each hoisting mechanism is consistent.
• the system also includes the following auxiliary controls: Synchronous control of the speed of each set of hoisting mechanisms.
• each hoisting motor adopts speed control as the main reference, and speed synchronous control as the most basic control.
• the manufacturing method because the hoisting mechanism wire rope winding method is multi-layer winding, the hoisting mechanism has different linear speeds at each layer for a certain motor speed.
• the control system cooperates with various external detection means to provide different speed reference signals for the inverter according to different layers, which can ensure the wire speed of each hoisting mechanism is consistent; the horizontal control of the hanger and the horizontal control of the suspension are The additional control means, the control system detects the relative position difference of each hanging point in the lifting process by the displacement signal provided by the position detecting encoder, and the coordinate plane formed by each lifting point is not parallel with the coordinate plane stored in the hovering mode. When the set value is exceeded, the position correction is performed; the hanging piece is kept at a basic level during operation.
• control system will adopt different control methods, and automatically complete the functions of data acquisition and calculation, function judgment and data correction, so that the control system is highly automated and intelligent.

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• Engineering & Computer Science (AREA)
• Automation & Control Theory (AREA)
• Mechanical Engineering (AREA)
• Control And Safety Of Cranes (AREA)

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• 2007
  • 2007-06-29 CN CNA200710011935XA patent/CN101139069A/zh active Pending
  • 2007-12-03 KR KR1020107001720A patent/KR101115773B1/ko active Active
  • 2007-12-03 JP JP2010513612A patent/JP5420539B2/ja active Active
  • 2007-12-03 RU RU2010102938/11A patent/RU2445250C2/ru active
  • 2007-12-03 WO PCT/CN2007/003427 patent/WO2009003333A1/zh not_active Ceased

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