Automatic lifting appliance anti-torsion control system and control method

Abstract

The invention belongs to the technical field of lifting appliance operation control, and particularly provides an automatic lifting appliance anti-torsion control system and control method.The method comprises the steps that a PID controller receives the current angle position, detected by an angle detection module, of a lifting appliance, and the rotation angle of the lifting appliance is calculated by accumulating the pulse number of an encoder; the PID controller takes an error between an angle detected by the angle detection module and an angle detected by the encoder as an optimization target and calculates and outputs a speed control quantity to the rotating motor to drive the rotating gear to drive the lifting appliance to rotate, and meanwhile, the angle detection module and the encoder repeatedly sense corresponding angle changes and feed the angle changes back to the PID controller; and the error meets the set requirement. By monitoring in real time and automatically adjusting the torsion angle of the lifting appliance, the safety and reliability of lifting operation are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sling operation control, and in particular to an automatic sling anti-twist control system and a control method. Background Art

[0002] Major ports are equipped with different numbers of large equipment such as gantry cranes and bridge cranes. The large equipment and hoists are flexibly connected by steel wire ropes. The large equipment is equipped with special cargo hoists (grabbers) to load and unload cargo from cargo ships. When the hoisted items are in operation or the hoist rotates, the items may swing or the steel wire rope may twist due to inertia or movement.

[0003] In order to ensure the stability of the spreader and the goods during operation and rotation, to ensure that the spreader as a whole remains parallel (collinear) with the port terminal or horizontal transport vehicle, and to improve the regularity of the loading and unloading positions and the operating efficiency, the spreader must have sufficient anti-swing and anti-torsion control and adjustment mechanisms to eliminate the twisting angles of the spreader itself and the wire rope.

[0004] During the operation of the spreader, the wire rope and the spreader itself twist. Once twisted, during the stage of unloading, the traditional way is to manually assist the hook stabilization under the machine to stabilize the spreader and then unload smoothly. Summary of the invention

[0005] In order to solve the problems of spreader rotation and torsion, the present invention provides an automated spreader anti-twist control system and a control method.

[0006] In a first aspect, the technical solution of the present invention provides an automated anti-twist control system for a spreader, wherein the spreader is arranged on a gantry crane, the gantry crane is provided with an elephant trunk, the spreader comprises a rotating mechanism, the rotating mechanism comprises a rotating gear and a rotating motor; the system further comprises an angle detection module and an encoder arranged on the rotating gear and rotating synchronously with the rotating gear; Angle detection module, used to detect the current angle position of the spreader; When the spreader rotates, the rotation angle of the spreader is calculated by accumulating the number of encoder pulses; The system also includes a PID controller, and the angle detection module and the encoder communicate with the PID controller respectively; the PID controller takes the error between the angle detected by the angle detection module and the angle detected by the encoder as the optimization target, calculates the output speed control amount to the rotating motor to drive the rotating gear to drive the hanger to rotate in the opposite direction to offset the error, that is, the twisting angle. At the same time, the angle detection module and the encoder repeatedly sense the corresponding angle changes and feed back to the PID controller until the error reaches the set requirements.

[0007] The PID controller consists of three units: proportional (P), integral (I) and differential (D). By setting the three parameters Kp (proportional coefficient), Ki (integral coefficient) and Kd (differential coefficient), the stability and response speed of the control system can be adjusted according to the characteristics of the controlled object.

[0008] Proportional control directly adjusts the output of the actuator according to the size of the error signal, so that the actuator action is proportional to the error. The larger the error, the greater the output to reduce the error as quickly as possible.

[0009] Integral control eliminates steady-state errors and improves the static accuracy of the system by accumulating error signals. As long as the error exists, the integral term will continue to accumulate until the error is zero.

[0010] Differential control improves the dynamic response speed and stability of the system by adjusting the rate of change of the error signal. When the error change rate is large, the differential term will produce a large output to suppress overshoot and oscillation of the system.

[0011] The process of PID controller calculating the output speed control quantity: The PID controller obtains the current angle position of the spreader from the angle detection module. At the same time, the actual angle position of the spreader when rotating is obtained from the encoder. The error between the two, that is, the difference between the target angle and the actual angle, is calculated. The error signal is multiplied by the proportional coefficient Kp to obtain the output of the proportional term. The output of the proportional term is proportional to the error and is used to quickly reduce the error. The error signal is integrated to obtain the cumulative error. The cumulative error is multiplied by the integral coefficient Ki to obtain the output of the integral term. The output of the integral term is used to eliminate steady-state errors and improve the static accuracy of the system. The error signal is differentiated to obtain the rate of change of the error. The rate of change of the error is multiplied by the differential coefficient Kd to obtain the output of the differential term. The output of the differential term is used to improve the dynamic response speed and stability of the system and suppress overshoot and oscillation of the system. The outputs of the proportional term, integral term and differential term are added to obtain the total output of the PID controller. The total output of the PID controller is the output speed control quantity, which is used to control the speed of the rotating motor and thus adjust the rotation angle of the spreader.

[0012] The angle detection module and encoder repeatedly sense the angle changes of the spreader and feed these changes back to the PID controller. The PID controller continuously adjusts the output speed control amount according to the feedback angle changes until the error reaches the set requirements.

[0013] In the calculation process, the values ​​of Kp, Ki and Kd are gradually adjusted according to the response of the system to achieve the best control effect. The goal of the PID controller is to make the error meet the set requirements. In practical applications, the error range needs to be set according to the accuracy requirements of the system and the actual situation.

[0014] As a preferred embodiment of the technical solution of the present invention, the sling further comprises an upper sling frame and a lower sling frame; the upper sling frame comprises a cable frame and an upper frame main beam; The lifting equipment lower frame includes the lifting equipment main beam, clamps, and lower frame electric control box; The lower frame electric control box is arranged on the main beam of the spreader, and the main beam of the spreader is hung with multiple clamps through the spreader beam; A rotating mechanism of the spreader is arranged in the middle of the spreader main beam, the upper part of the rotating mechanism is connected to the upper frame main beam, and a cable frame is arranged on the upper part of the upper frame main beam.

[0015] As a preferred embodiment of the technical solution of the present invention, the angle detection module includes a transmitter arranged on the lower frame electrical control box and a receiver arranged on the platform at the end of the trunk beam; the transmitter and the receiver are arranged relatively to each other on the same vertical line; when the angle of the sling changes, the incident position of the infrared signal emitted by the transmitter on the receiver will also change, and the receiver analyzes the position of the infrared signal source emitted by the transmitter fixed on the lower frame electrical control box of the sling, and then obtains the current angle position of the sling.

[0016] The transmitter is installed on the lower shelf electrical control box and is responsible for transmitting infrared signals. This infrared signal can be continuous or pulsed. The transmitter usually contains an infrared light emitting diode or other types of infrared emitting elements, which convert electrical energy into infrared energy through electronic devices and radiate it.

[0017] The receiver is set on the platform at the end of the elephant trunk beam, and is set opposite to the transmitter on the same vertical line. The receiver is responsible for receiving the infrared signal emitted by the transmitter and processing it. The receiver usually contains infrared photodiodes or other types of infrared receiving elements, as well as electronic devices such as amplifiers, demodulators and filters, which are used to amplify, demodulate and convert the received weak signals into electrical signals that can be processed by subsequent circuits. The transmitter emits an infrared signal, which propagates in space and points to the receiver. The receiver receives the infrared signal emitted by the transmitter. Since the transmitter and the receiver are set relative to each other on the same vertical line, when the angle of the spreader (and the transmitter fixed on the spreader) changes, the incident position of the infrared signal emitted by the transmitter on the receiver will also change. The electronic device inside the receiver processes the received signal, and by analyzing the position change of the signal, the current angle position of the spreader can be calculated. This process usually involves steps such as signal amplification, demodulation, filtering and position calculation. The functions of the existing transmitter and receiver are not described here. The transmitter and the receiver work together, using the principles of infrared transmission and reception and signal processing to achieve accurate detection of the spreader angle.

[0018] As a preferred embodiment of the technical solution of the present invention, the system also includes an elephant trunk bridge PLC controller, a hoist execution PLC controller and a hoist control PLC controller; the encoder is connected to the hoist execution PLC controller, the hoist execution PLC controller is communicatively connected to the elephant trunk bridge PLC controller, the angle detection module is connected to the elephant trunk bridge PLC controller, and the elephant trunk bridge PLC controller is connected to the rotating motor through the hoist execution PLC controller.

[0019] The encoder is installed on the rotating gear to detect the actual rotation angle of the spreader in real time, that is, the angle between the spreader and the horizontal line reference. This angle information is transmitted to the spreader execution PLC controller through the encoder as important feedback data for controlling the spreader rotation.

[0020] The spreader executes the PLC controller and outputs the data to the trunk beam PLC controller.

[0021] The angle detection module provides another dimension of feedback for the control system by detecting the angle between the hanging beam on the sling and the actual hanging beam on the sling (i.e. the twisting angle of the sling). It is connected to the elephant trunk beam PLC controller and transmits the detected angle information to the elephant trunk beam PLC controller in real time. The elephant trunk beam PLC controller transmits the information of these two data sources to the sling control PLC controller.

[0022] The spreader control PLC controller is responsible for integrating the data from various sensors and calculating the control instructions according to the control logic. It gives the rotating motor to instruct it to rotate at the appropriate speed and direction, thereby achieving accurate compensation for the spreader twisting. This hierarchical control structure makes the system more flexible and scalable, and also improves the reliability and stability of the system.

[0023] As a preferred embodiment of the technical solution of the present invention, the system also includes a first wireless communication device arranged on the sling and a second wireless communication device arranged on the trunk bridge; the sling execution PLC controller is connected to the trunk bridge PLC controller via the first wireless communication device and the second wireless communication device in turn.

[0024] As a preferred embodiment of the technical solution of the present invention, the system also includes a hanger following function switch and an automatic PLC controller; The spreader following function switch is connected to the automation PLC controller, and the spreader following function is turned on or off according to the switch signal of the spreader following function switch; the automation PLC controller is connected to the spreader control PLC controller through the DP / DP connector, and the spreader following function switch signal is input to the spreader control PLC controller.

[0025] As a preferred embodiment of the technical solution of the present invention, the trunk bridge PLC controller and the hoist control PLC controller are connected via a network cable using PN communication, the angle detection module is connected to the trunk bridge PLC controller via DP communication; the encoder and the hoist execution PLC controller communicate via PN.

[0026] PN (Profinet) communication is a network protocol for real-time industrial automation communication that supports high-speed data transmission. This communication method can ensure that a large amount of data and control instructions can be exchanged between the trunk bridge PLC controller and the spreader control PLC controller in real time and accurately, thereby ensuring the response speed and accuracy of the system. PN communication has a high degree of reliability and stability, which can reduce errors and losses during data transmission and ensure the stable operation of the system.

[0027] DP (Profibus DP) communication is a commonly used industrial automation fieldbus communication protocol suitable for distributed control systems. Through DP communication, multiple detection modules can exchange data with the elephant trunk bridge PLC controller in parallel, improving the overall control efficiency and response speed of the system. DP communication is relatively low-cost in hardware and software, and is suitable for occasions where a large number of devices need to be connected. Using DP communication can reduce the overall cost of the system. The encoder is used to accurately measure the rotation angle of the spreader, and its data is crucial for controlling the precise movement of the spreader. The use of PN communication can ensure high-precision data transmission between the encoder and the spreader execution PLC controller, reducing data errors and losses. Through PN communication, the encoder can feed back the spreader's rotation angle information to the spreader execution PLC controller in real time, so that the controller can adjust the control strategy in time to ensure the accurate movement of the spreader.

[0028] As a preferred embodiment of the technical solution of the present invention, the hoist control PLC controller integrates an A / D amplifier to amplify the angle signal sensed by the encoder and the angle detection module, calculate the angle difference, and then obtain the deviation between the output speed and the given speed, generate an adjustment instruction for eliminating the angle difference through a PID controller, and output the speed control amount to the rotating motor to drive the hoist to rotate and adjust the angle difference.

[0029] In a second aspect, the technical solution of the present invention further provides an automatic hoist anti-twist control method, comprising the following steps: The PID controller receives the current angle position of the spreader detected by the angle detection module, and calculates the rotation angle of the spreader by accumulating the number of pulses of the encoder; The PID controller takes the error between the angle detected by the angle detection module and the angle detected by the encoder as the optimization target, calculates the output speed control quantity to the rotating motor to drive the rotating gear to drive the hanger to rotate. At the same time, the angle detection module and the encoder repeatedly sense the corresponding angle changes and feed back to the PID controller until the error reaches the set requirements.

[0030] As a preferred embodiment of the technical solution of the present invention, the method further comprises: When the spreader rotates to the target angle, due to the rotation inertia, the PID controller outputs a reverse speed V1 according to the detection information of the angle detection module to control the rotation of the rotating mechanism, and at the same time gives a speed V2 according to the encoder detection information to control the rotation of the rotating mechanism; the sum of V1 and V2 will be used as the final speed for the rotating motor; the target angle is the target position angle of the spreader required to keep the spreader always parallel to the landside track.

[0031] The PID controller receives the current angle position of the spreader detected by the angle detection module. At the same time, the actual rotation angle of the spreader is calculated by accumulating the number of pulses of the encoder. The target angle (the target position angle of the spreader calculated to keep the spreader always parallel to the landside track) is compared with the actual angle to obtain the error. The output speed control quantity is calculated based on the error using the PID control algorithm. This includes the proportional term (proportional to the error), the integral term (accumulation of the error), and the differential term (rate of change of the error). When the spreader rotates to the target angle, due to the rotation inertia, the PID controller will output two speed control quantities V1 and V2 respectively according to the detection information of the angle detection module and the encoder. V1 is the reverse speed given according to the information of the angle detection module, which is used to offset the overshoot caused by inertia. V2 is the speed given according to the encoder information, which is used to accurately control the rotation of the rotating mechanism. The sum of these two speed control quantities will be the final speed given to the rotating motor.

[0032] It can be seen from the above technical solutions that the present invention has the following advantages: the use of a high-precision encoder combined with an angle detection module can accurately sense and adjust the deviation between the actual angle and the target angle of the sling, realize refined control of the lifting operation, and ensure that the position of the cargo during the lifting process is accurate. By real-time monitoring and automatic adjustment of the torsion angle of the sling, the system effectively avoids safety hazards such as tilting and falling of cargo caused by accidental torsion of the sling, and significantly improves the safety and reliability of the lifting operation. Automated control reduces the need for manual intervention and shortens the time to adjust the angle of the sling, especially in complex or high-demand lifting environments, which can significantly improve overall work efficiency and reduce labor costs. The integrated PID control algorithm can quickly adjust the control strategy based on real-time feedback, effectively suppress system fluctuations, and enhance the stability and robustness of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 is a schematic block diagram of a system according to an embodiment of the present invention.

[0035] Figure 2 It is a schematic diagram of system communication connection according to an embodiment of the present invention.

[0036] Figure 3 Schematic diagram of PID control in an embodiment of the present invention.

[0037] Figure 4 It is a schematic diagram of the hanger structure.

[0038] Figure 5 Schematic diagram of angles detected in an embodiment of the present invention.

[0039] In the figure, 1-clamp, 2-hoisting beam, 3-hoisting main beam, 4-lower rack electric control box, 5-transmitter, 6-rotating mechanism, 7-cable frame, 8-upper rack main beam. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0041] The hoisting device is set on the gantry crane, which is equipped with an elephant trunk beam. The gantry crane, also known as the portal crane, is a commonly used lifting equipment in ports, factories and other places. It has a strong lifting capacity and flexible operability. It is mainly used for lifting, handling and stacking of goods, and is an indispensable and important equipment in modern logistics and production processes.

[0042] The trunk is an important part of the gantry crane. It connects the boom and turntable of the gantry crane and plays a role in supporting and transmitting force. The spreader is a key component of the gantry crane used to connect the cargo and the crane. When setting the spreader on the gantry crane, factors such as the type of spreader, load capacity, operational safety, and maintenance need to be considered. At the same time, it is also necessary to select the appropriate spreader and install and adjust it correctly according to the actual situation of the cargo and the requirements of the lifting operation.

[0043] like Figure 1 As shown, an embodiment of the present invention provides an automated anti-twist control system for a spreader, wherein the spreader includes a rotating mechanism, wherein the rotating mechanism includes a rotating gear and a rotating motor; the system also includes an angle detection module and an encoder arranged on the rotating gear and rotating synchronously with the rotating gear; Angle detection module, used to detect the current angle position of the spreader; When the spreader rotates, the rotation angle of the spreader is calculated by accumulating the number of encoder pulses; The system also includes a PID controller, and the angle detection module and the encoder communicate with the PID controller respectively; the PID controller takes the error between the angle detected by the angle detection module and the angle detected by the encoder as the optimization target, calculates the output speed control amount to the rotating motor to drive the rotating gear to drive the hanger to rotate in the opposite direction to offset the error, that is, the twisting angle. At the same time, the angle detection module and the encoder repeatedly sense the corresponding angle changes and feed back to the PID controller until the error reaches the set requirements.

[0044] The PID controller consists of three units: proportional (P), integral (I) and differential (D). By setting the three parameters Kp (proportional coefficient), Ki (integral coefficient) and Kd (differential coefficient), the stability and response speed of the control system can be adjusted according to the characteristics of the controlled object.

[0045] Proportional control directly adjusts the output of the actuator according to the size of the error signal, so that the actuator action is proportional to the error. The larger the error, the greater the output to reduce the error as quickly as possible.

[0046] Integral control eliminates steady-state errors and improves the static accuracy of the system by accumulating error signals. As long as the error exists, the integral term will continue to accumulate until the error is zero.

[0047] Differential control improves the dynamic response speed and stability of the system by adjusting the rate of change of the error signal. When the error change rate is large, the differential term will produce a large output to suppress overshoot and oscillation of the system.

[0048] The process of PID controller calculating the output speed control quantity: The PID controller obtains the current angle position of the spreader from the angle detection module. At the same time, the actual angle position of the spreader when rotating is obtained from the encoder. The error between the two, that is, the difference between the target angle and the actual angle, is calculated. The error signal is multiplied by the proportional coefficient Kp to obtain the output of the proportional term. The output of the proportional term is proportional to the error and is used to quickly reduce the error. The error signal is integrated to obtain the cumulative error. The cumulative error is multiplied by the integral coefficient Ki to obtain the output of the integral term. The output of the integral term is used to eliminate steady-state errors and improve the static accuracy of the system. The error signal is differentiated to obtain the rate of change of the error. The rate of change of the error is multiplied by the differential coefficient Kd to obtain the output of the differential term. The output of the differential term is used to improve the dynamic response speed and stability of the system and suppress overshoot and oscillation of the system. The outputs of the proportional term, integral term and differential term are added to obtain the total output of the PID controller. The total output of the PID controller is the output speed control quantity, which is used to control the speed of the rotating motor and thus adjust the rotation angle of the spreader.

[0049] The angle detection module and encoder repeatedly sense the angle changes of the spreader and feed these changes back to the PID controller. The PID controller continuously adjusts the output speed control amount according to the feedback angle changes until the error reaches the set requirements.

[0050] In the calculation process, the values ​​of Kp, Ki and Kd are gradually adjusted according to the response of the system to achieve the best control effect. The goal of the PID controller is to make the error meet the set requirements. In practical applications, the error range needs to be set according to the accuracy requirements of the system and the actual situation.

[0051] In the embodiment of the present invention, Figure 4 As shown, the sling also includes an upper sling frame and a lower sling frame; the upper sling frame includes a cable frame and an upper frame main beam; The lifting device lower frame includes a lifting device main beam 3, a clamp 1, and a lower frame electric control box 4; A lower frame electric control box 4 is arranged on the main beam 3 of the spreader, and a plurality of clamps 1 are suspended on the main beam 3 of the spreader through the spreader suspension beam 2; A rotating mechanism 6 of the spreader is arranged in the middle of the spreader main beam 3 , the upper part of the rotating mechanism 6 is connected to the upper frame main beam 8 , and the upper part of the upper frame main beam 8 is arranged with a cable frame 7 .

[0052] In some embodiments, the angle detection module includes a transmitter 5 arranged on the lower frame electrical control box 4 and a receiver arranged on the platform at the end of the trunk beam; the transmitter and the receiver are arranged relative to each other on the same vertical line; when the angle of the sling changes, the incident position of the infrared signal emitted by the transmitter on the receiver will also change, and the receiver analyzes the position of the infrared signal source emitted by the transmitter 5 fixed on the lower frame electrical control box 4 of the sling, and then obtains the current angle position of the sling.

[0053] The transmitter installed on the lower shelf electric control box is responsible for emitting infrared signals. This infrared signal can be continuous or pulsed. The transmitter usually contains an infrared light emitting diode or other types of infrared emitting elements, which convert electrical energy into infrared energy through electronic devices and radiate it.

[0054] The receiver is set on the platform at the end of the elephant trunk beam, and is set opposite to the transmitter on the same vertical line. The receiver is responsible for receiving the infrared signal emitted by the transmitter and processing it. The receiver usually contains infrared photodiodes or other types of infrared receiving elements, as well as electronic devices such as amplifiers, demodulators and filters, which are used to amplify, demodulate and convert the received weak signals into electrical signals that can be processed by subsequent circuits. The transmitter emits an infrared signal, which propagates in space and points to the receiver. The receiver receives the infrared signal emitted by the transmitter. Since the transmitter and the receiver are set relative to each other on the same vertical line, when the angle of the spreader (and the transmitter fixed on the spreader) changes, the incident position of the infrared signal emitted by the transmitter on the receiver will also change. The electronic device inside the receiver processes the received signal, and by analyzing the position change of the signal, the current angle position of the spreader can be calculated. This process usually involves steps such as signal amplification, demodulation, filtering and position calculation. The functions of the existing transmitter and receiver are not described here. The transmitter and the receiver work together, using the principles of infrared transmission and reception and signal processing to achieve accurate detection of the spreader angle.

[0055] In some embodiments, two transmitters are provided, both of which are installed on the lower electrical control box, transmitter beacon1 and transmitter beacon2, and the distance between beacon1 and beacon2 is controlled in the range of 40-60 cm. At this time, one transmitter needs to be in the same plane as the receiver. For this configuration, the signals emitted by the two transmitters are received by the same receiver. Due to the different positions of the two transmitters, the paths of the signals they emit to reach the receiver are also different, thus forming two different measurement direction vectors. The dual-transmitter-single-receiver configuration can reduce the measurement uncertainty by increasing the intersection angle of the optical signal. When the intersection angle is within a suitable range, the measurement accuracy will be relatively high.

[0056] The angle detection module of Arck is used to detect the real-time rotation angle value Ø of the current torsion of the spreader. The anti-twist process is to offset the torsion angle Ø through the reverse rotation of the rotating mechanism of the spreader's lower frame. The whole process is a PI adjustment process. The premise of anti-twist control is that the spreader has reached the target angle, but due to the rotation inertia, it will continue to rotate to produce a torsion angle Ø. At this time, the anti-twist function is turned on. Due to the existence of the Ø angle, the rotating mechanism will give a reverse speed V1 to offset the torsion inertia. For this reason, there is an angle difference α between the actual angle of the spreader and the target angle. At the same time, in order to rotate the spreader back to the target position to offset this α angle, the anti-twist system will give another speed V2. V2 will drop rapidly as the α angle decreases. At the same time, the speed of V1 will gradually decrease as the angle Ø decreases. The sum of V1 and V2 will be the final speed given to the rotating motor.

[0057] In the automatic spreader anti-torsion control system, the angle detection module plays a core role, which is used to detect the rotation angle value of the current spreader twist in real time. This detection process is based on the precise analysis of the position change of the signal source fixed on the spreader.

[0058] Specifically, the PID controller calculates a speed control quantity through a complex algorithm, which is designed to guide the rotating mechanism of the spreader's lower frame to rotate at an appropriate speed and direction. The rotating mechanism usually includes a rotating gear and a rotating motor, which perform reverse rotation actions according to the instructions of the PID controller to offset the twisting angle of the spreader. This control process is a closed-loop feedback system, which means that the angle detection module continuously monitors the rotation angle of the spreader and feeds back the latest angle information to the PID controller. The PID controller recalculates the speed control quantity based on the new angle difference and continues to adjust the movement of the rotating mechanism until the rotation angle of the spreader reaches or approaches the preset target angle, thereby achieving stable control of the spreader.

[0059] The entire anti-twist system is a process of gradually offsetting the angles α and Ø. Due to the influence of external factors such as wind force and center of gravity offset, the sum of V1 and V2, Vq, is unlikely to approach 0. At the same time, frequent and rapid switching of the inverter's output direction is also more likely to cause overcurrent of the inverter and overheating of the rotating motor. Therefore, a threshold value needs to be set. When Vq is lower than the output frequency of 2HZ, the anti-twist system will no longer provide a speed reference.

[0060] In some embodiments, Figure 2As shown, the system also includes an elephant trunk bridge PLC controller, a sling execution PLC controller and a sling control PLC controller; the encoder is connected to the sling execution PLC controller, the sling execution PLC controller is communicatively connected to the elephant trunk bridge PLC controller, the angle detection module is connected to the elephant trunk bridge PLC controller, and the elephant trunk bridge PLC controller is connected to the rotating motor through the sling execution PLC controller.

[0061] The encoder is installed on the rotating gear to detect the actual rotation angle of the spreader in real time, that is, the angle between the spreader and the horizontal line reference. This angle information is transmitted to the spreader execution PLC controller through the encoder as important feedback data for controlling the spreader rotation.

[0062] The spreader executes the PLC controller and outputs the data to the trunk beam PLC controller.

[0063] The angle detection module provides another dimension of feedback for the control system by detecting the angle between the hanging beam on the sling and the actual hanging beam on the sling (i.e. the twisting angle of the sling). It is connected to the elephant trunk beam PLC controller and transmits the detected angle information to the elephant trunk beam PLC controller in real time. The elephant trunk beam PLC controller transmits the information of these two data sources to the sling control PLC controller.

[0064] The spreader control PLC controller is responsible for integrating the data from various sensors and calculating the control instructions according to the control logic. It gives the rotating motor to instruct it to rotate at the appropriate speed and direction, thereby achieving accurate compensation for the spreader twisting. This hierarchical control structure makes the system more flexible and scalable, and also improves the reliability and stability of the system.

[0065] In some embodiments, the system also includes a first wireless communication device arranged on the sling and a second wireless communication device arranged on the trunk bridge; the sling execution PLC controller is connected to the trunk bridge PLC controller via the first wireless communication device and the second wireless communication device in turn.

[0066] In some embodiments, the system further comprises a spreader follow function switch and an automated PLC controller; The spreader following function switch is connected to the automation PLC controller, and the spreader following function is turned on or off according to the switch signal of the spreader following function switch; the automation PLC controller is connected to the spreader control PLC controller through the DP / DP connector, and the spreader following function switch signal is input to the spreader control PLC controller.

[0067] In some embodiments, the trunk bridge PLC controller and the hoist control PLC controller are connected via a network cable using PN communication, the angle detection module is connected to the trunk bridge PLC controller via DP communication; the encoder and the hoist execution PLC controller communicate via PN.

[0068] PN (Profinet) communication is a network protocol for real-time industrial automation communication that supports high-speed data transmission. This communication method can ensure that a large amount of data and control instructions can be exchanged between the trunk bridge PLC controller and the spreader control PLC controller in real time and accurately, thereby ensuring the response speed and accuracy of the system. PN communication has a high degree of reliability and stability, which can reduce errors and losses during data transmission and ensure the stable operation of the system.

[0069] DP (Profibus DP) communication is a commonly used industrial automation fieldbus communication protocol suitable for distributed control systems. Through DP communication, multiple detection modules can exchange data with the elephant trunk bridge PLC controller in parallel, improving the overall control efficiency and response speed of the system. DP communication is relatively low-cost in hardware and software, and is suitable for occasions where a large number of devices need to be connected. Using DP communication can reduce the overall cost of the system. The encoder is used to accurately measure the rotation angle of the spreader, and its data is crucial for controlling the precise movement of the spreader. The use of PN communication can ensure high-precision data transmission between the encoder and the spreader execution PLC controller, reducing data errors and losses. Through PN communication, the encoder can feed back the spreader's rotation angle information to the spreader execution PLC controller in real time, so that the controller can adjust the control strategy in time to ensure the accurate movement of the spreader.

[0070] In some embodiments, Figure 3 As shown, the spreader control PLC controller integrates an A / D amplifier to amplify the angle signal sensed by the encoder and the angle detection module, calculate the angle difference, and then obtain the deviation between the output speed and the given speed. The PID controller generates an adjustment instruction for eliminating the angle difference, and outputs the speed control amount to the rotating motor to drive the spreader to rotate and adjust the angle difference.

[0071] The angle detection module senses the angle Ø between the upper hanging beam, the lower hanging beam and the sling, and the encoder senses the angle α between the lower hanging beam, the sling and the horizontal line reference. The angle diagram is shown in Figure 5 As shown in the figure, the angle signal sensed by the encoder and the angle detection module is amplified by the integrated amplifier A / D, and the proportional gain is adjusted according to the deviation e between the output speed and the given speed. The PID controller adjusts the angles Ø and α through proportional control, and the output speed control amount V=V θ +V α , V θ is the velocity component that adjusts the angle Ø, V αIt is the speed component that adjusts the angle α. The speed control quantity V is output to the motor. The motor drives the hanger to rotate and adjust the angles Ø and α. The angle detection module and encoder repeatedly sense the angle changes and feed back to the PID control to form a closed-loop control that adjusts the angle through speed changes.

[0072] It should be noted that the spreader rotation control is divided into automatic control and manual control.

[0073] Manual control means that the driver controls the spreader to rotate clockwise or counterclockwise through the manual adjustment button. Currently, the manual adjustment button only gives a fixed speed (35HZ speed).

[0074] Automatic control refers to the function of opening the spreader following in the spreader rotation control. There is an automatic following function switch on the CMS and the local operation station to start the function; the spreader rotation angle is controlled between +90 degrees and -90 degrees. The gantry crane rotation area is divided into four quadrants, and the spreader following angles in the four quadrants are calculated separately (the following angle is the angle parallel to the lane direction).

[0075] When the gantry crane is manually operated to rotate at any angle within the landside lane, the spreader will automatically rotate to an angle parallel to the lane. When the gantry crane is manually operated to rotate to the seaside (exceeding the seaside setting position, the current setting of the gantry crane rotation is between 120-240 degrees as the seaside position), the manual automatic follow-up stop. When the lifting height is less than 5.5 meters above the ground (the bottom of the pulp bag is about 1 meter away from the car) within the landside lane, the manual automatic follow-up stop. The angular velocity of the spreader rotation will be consistent with the angular velocity of the gantry crane rotation. (After measurement, the angular velocity of the temporary spreader rotation speed is 5.75 degrees / second when the gantry crane rotates at full speed at 50HZ, and the angular velocity of the gantry crane rotation at full speed is 7.45 degrees / second. The current gantry crane rotation speed limit is 70%. To use this function, the maximum speed of the gantry crane rotation needs to be limited to less than 77%).

[0076] When the gantry crane is in automatic operation, it will record the starting position and target position of the rotation when the automation starts, and use this to calculate the rotation angle of the spreader when it reaches the target position, and then calculate the rotation angle of the entire automation process based on the current spreader rotation angle, and reach the target position according to the preset acceleration and deceleration curve. The conditions for the spreader to follow during automatic operation: the automatic following is turned on when the automation starts; the automatic following function exits when the gantry crane rotates on the sea side and the automation is manually interrupted; when the gantry crane rotates back to the landside track range, the automatic following exits and enters the manual automatic following mode when the automation step is manually interrupted; when the automatic lifting height is lower than 5.5 meters, the automatic following stops working.

[0077] The anti-twist control of the spreader is activated through the spreader PID control switch in the CMS touch screen. The anti-twist control of the spreader can only be turned on in the automatic following mode and the manual automatic following mode.

[0078] In the manual automatic following mode, the anti-twist function of the spreader is only activated in the land side lane range; when turning to the sea side, the anti-twist function automatically stops; when the land side lifting is lower than 5.5 meters, the anti-twist function automatically stops.

[0079] In the automatic following mode, the anti-twist function acts on the automatic operation of the gantry crane. The function is only enabled when the automatic rotation is in place, and anti-twist adjustment will be performed on both the sea and land sides. When the gantry crane is automatically exited, the automatic following and anti-twist function will be exited simultaneously. When the automatic lifting and lowering height on the land side is lower than 5.5 meters, the anti-twist function will also be triggered to exit.

[0080] The embodiment of the present invention also provides an automatic lifting device anti-twist control method, comprising the following steps: Step 1: The PID controller receives the current angle position of the spreader detected by the angle detection module, and calculates the rotation angle of the spreader by accumulating the number of pulses of the encoder; Step 2: The PID controller takes the error between the angle detected by the angle detection module and the angle detected by the encoder as the optimization target, calculates the output speed control amount to drive the rotating motor to drive the rotating gear to drive the hanger to rotate. At the same time, the angle detection module and the encoder repeatedly sense the corresponding angle changes and feed back to the PID controller until the error reaches the set requirements.

[0081] In some embodiments, the method further comprises: When the spreader rotates to the target angle, due to the rotation inertia, the PID controller outputs the reverse speed V1 according to the detection information of the angle detection module to control the rotation of the rotating mechanism, and at the same time gives the speed V2 according to the encoder detection information to control the rotation of the rotating mechanism; the sum of V1 and V2 will be used as the final speed of the rotating motor; the target angle is the target position angle of the spreader calculated to keep the spreader always parallel to the landside track.

[0082] The PID controller receives the current angle position of the spreader detected by the angle detection module. At the same time, the actual rotation angle of the spreader is calculated by accumulating the number of pulses of the encoder. The target angle (the target position angle of the spreader calculated to keep the spreader always parallel to the landside track) is compared with the actual angle to obtain the error. The output speed control quantity is calculated based on the error using the PID control algorithm. This includes the proportional term (proportional to the error), the integral term (accumulation of the error), and the differential term (rate of change of the error). When the spreader rotates to the target angle, due to the rotation inertia, the PID controller will output two speed control quantities V1 and V2 respectively according to the detection information of the angle detection module and the encoder. V1 is the reverse speed given according to the information of the angle detection module, which is used to offset the overshoot caused by inertia. V2 is the speed given according to the encoder information, which is used to accurately control the rotation of the rotating mechanism. The sum of these two speed control quantities will be the final speed given to the rotating motor.

[0083] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0084] An embodiment of an automatic hoist anti-twist control method provided in an embodiment of the present invention belongs to the same inventive concept as the automatic hoist anti-twist control system of the above-mentioned embodiments. For details not described in detail in the embodiment of the automatic hoist anti-twist control method, reference can be made to the embodiment of the above-mentioned automatic hoist anti-twist control method.

[0085] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention.

Claims

1. An automatic anti-twist control system for a spreader, wherein the spreader is arranged on a gantry crane, the gantry crane is provided with an elephant trunk beam, and the spreader includes a rotating mechanism, characterized in that: The rotating mechanism includes a rotating gear and a rotating motor; the system also includes an angle detection module and an encoder arranged on the rotating gear and rotating synchronously with the rotating gear; Angle detection module, used to detect the current angle position of the spreader; When the spreader rotates, the rotation angle of the spreader is calculated by accumulating the number of encoder pulses; The system also includes a PID controller, and the angle detection module and the encoder communicate with the PID controller respectively; the PID controller takes the error between the angle detected by the angle detection module and the angle detected by the encoder as the optimization target, calculates the output speed control amount to the rotating motor to drive the rotating gear to drive the hanger to rotate in the opposite direction to offset the error, that is, the twisting angle. At the same time, the angle detection module and the encoder repeatedly sense the corresponding angle changes and feed back to the PID controller until the error reaches the set requirements.

2. The automatic lifting device anti-twist control system according to claim 1, characterized in that: The sling also includes an upper sling frame and a lower sling frame; the upper sling frame includes a cable frame and an upper frame main beam; The lifting equipment lower frame includes the lifting equipment main beam, clamps, and lower frame electric control box; The lower frame electric control box is arranged on the main beam of the spreader, and the main beam of the spreader is hung with multiple clamps through the spreader beam; A rotating mechanism of the spreader is arranged in the middle of the spreader main beam, the upper part of the rotating mechanism is connected to the upper frame main beam, and a cable frame is arranged on the upper part of the upper frame main beam.

3. The automatic lifting device anti-twist control system according to claim 2, characterized in that: The angle detection module includes a transmitter arranged on the lower frame electric control box and a receiver arranged on the platform at the end of the trunk beam; the transmitter and the receiver are arranged relative to each other on the same vertical line; when the angle of the spreader changes, the incident position of the infrared signal emitted by the transmitter on the receiver will also change, and the receiver analyzes the position of the infrared signal source emitted by the transmitter fixed on the lower frame electric control box of the spreader, and then obtains the current angle position of the spreader.

4. The automatic lifting device anti-twist control system according to claim 3, characterized in that: The system also includes an elephant trunk bridge PLC controller, a sling execution PLC controller and a sling control PLC controller; the encoder is connected to the sling execution PLC controller, the sling execution PLC controller is communicatively connected to the elephant trunk bridge PLC controller, the angle detection module is connected to the elephant trunk bridge PLC controller, and the elephant trunk bridge PLC controller is connected to the rotating motor through the sling execution PLC controller.

5. The automatic lifting device anti-twist control system according to claim 4, characterized in that: The system also includes a first wireless communication device arranged on the sling and a second wireless communication device arranged on the trunk bridge; the sling execution PLC controller is connected with the trunk bridge PLC controller via the first wireless communication device and the second wireless communication device in sequence.

6. The automatic hoist anti-twist control system according to claim 5, characterized in that: The system also includes a spreader follow function switch and an automated PLC controller; The spreader following function switch is connected to the automation PLC controller, and the spreader following function is turned on or off according to the switch signal of the spreader following function switch; the automation PLC controller is connected to the spreader control PLC controller through the DP / DP connector, and the spreader following function switch signal is input to the spreader control PLC controller.

7. The automatic hoisting device anti-twist control system according to claim 6, characterized in that: The trunk bridge PLC controller and the hoisting equipment control PLC controller are connected via a network cable using PN communication, and the angle detection module is connected to the trunk bridge PLC controller via DP communication; the encoder and the hoisting equipment execution PLC controller communicate via PN.

8. The automatic hoisting device anti-twist control system according to claim 7, characterized in that: The PLC controller of the spreader control integrates an A / D amplifier to amplify the angle signal sensed by the encoder and the angle detection module, calculate the angle difference, and then obtain the deviation between the output speed and the given speed. The adjustment command for eliminating the angle difference is generated through the PID controller, and the speed control amount is output to the rotating motor to drive the spreader to rotate and adjust the angle difference.

9. An automatic lifting device anti-twist control method, characterized in that: The steps include: The PID controller receives the current angle position of the spreader detected by the angle detection module, and calculates the rotation angle of the spreader by accumulating the number of pulses of the encoder; The PID controller takes the error between the angle detected by the angle detection module and the angle detected by the encoder as the optimization target, calculates the output speed control quantity to the rotating motor to drive the rotating gear to drive the hanger to rotate. At the same time, the angle detection module and the encoder repeatedly sense the corresponding angle changes and feed back to the PID controller until the error reaches the set requirements.

10. The automatic lifting device anti-twist control method according to claim 9, characterized in that: The method further includes: When the spreader rotates to the target angle, due to the rotation inertia, the PID controller outputs a reverse speed V1 according to the detection information of the angle detection module to control the rotation of the rotating mechanism, and at the same time gives a speed V2 according to the encoder detection information to control the rotation of the rotating mechanism; the sum of V1 and V2 will be used as the final speed for the rotating motor; the target angle is the target position angle of the spreader required to keep the spreader always parallel to the landside track.

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