Laser-based Gantry Crane Trolley Speed Control System

Abstract

The present invention provides a speed control system for the trolley of a gantry mobile crane based on laser, which comprises: a gantry mobile crane body; a trolley controller; a hoisting position encoder for detecting the current hoisting height value of the container with the spreader; three laser transmitters; three laser receivers which are respectively arranged diagonally opposite to and correspond one by one with the laser transmitters, receive the laser emission data emitted by the laser transmitters to form laser reception data, and perform CRC check, and when the check is correct, it is determined that there is no container and a confirmation signal is sent out; a PLC controller which is communicatively connected with the trolley controller, the hoisting position encoder and the laser receiver; the PLC controller confirms the current height value of the container yard according to the received confirmation signal, and when the hoisting height value of the container with the spreader is higher than the current height value of the container yard, a full-speed driving command is sent to the trolley controller. The present invention can improve the operation efficiency of the mobile crane, reduce the energy consumption of the container hoisting operation, and reduce the wear of the wire rope.

Description

Technical Field

[0001] The present invention belongs to the field of terminal operations, and particularly relates to a speed control system for the trolley of a gantry rubber-tyred crane based on laser. Background Art

[0002] Due to safety considerations during operation, in the conventional container lifting operation of a rubber-tyred crane, the spreader must be lifted to the "highest position" (upper end limit position) before the trolley can move forward at full speed. Otherwise, it can only move forward at a very slow safe speed. This results in extremely low efficiency in operating in areas with low containers and high container stacks in the container yard. In addition, it also wastes energy consumption and accelerates the aging of the wire ropes.

[0003] In other port terminals, there have been related technical projects on "preventing bowling" laser detection of container positions in the container yard. Although they have a certain technical content, their use effects do not meet expectations, and there are disadvantages such as a relatively high failure rate, the safety level not being sufficient for drivers to fully rely on, and a relatively high price. Summary of the Invention

[0004] One object of the present invention is to provide a speed control system for the trolley of a gantry rubber-tyred crane based on laser, and to provide at least the advantages described hereinafter.

[0005] Another object of the present invention is to provide a speed control system for the trolley of a gantry rubber-tyred crane based on laser, which can improve the operation efficiency of the rubber-tyred crane, reduce the energy consumption of container lifting operations, and reduce the wear of the wire ropes.

[0006] The technical solution of the present invention is as follows:

[0007] A speed control system for the trolley of a gantry rubber-tyred crane based on laser, comprising:

[0008] A gantry rubber-tyred crane body, which has a gantry support and a trolley moving on the crossbeam of the gantry support. The gantry support includes a first column located downstream on the sea side and a second column located upstream on the land side;

[0009] A trolley controller, which is electrically connected to the trolley and drives the trolley to travel;

[0010] A hoisting position encoder, which is used to detect the current hoisting height value of the container;

[0011] Three laser emitters, which are respectively arranged at a first height position, a second height position, and a third height position on the first column. The second height position is higher than the first height position, and the third height position is higher than the second height position;

[0012] Three laser receivers, which are respectively arranged at the first height position, the second height position and the third height position of the second column, and the laser receivers are arranged diagonally opposite to the laser transmitter and correspond one by one. The laser receivers receive the laser emission data emitted by the laser transmitter to form laser reception data, and perform CRC check on it and the laser emission data. When the check is correct, it is judged that there is no container between the laser transmitter and the laser receiver and an acknowledgement signal is sent.

[0013] A PLC controller, which is communicatively connected with the trolley controller, the hoisting position encoder and the laser receiver; the PLC controller confirms the current height value of the container area according to the received acknowledgement signal. When the height value of the hoisting with container is higher than the current height value of the container area, a full-speed driving command is sent to the trolley controller.

[0014] Preferably, in the laser-based Gantry Rubber Tyred Gantry Crane trolley speed control system,

[0015] The first height position is at 6.7 m above the ground;

[0016] The second height position is at 9.6 m above the ground;

[0017] The third height position is at 12.2 m above the ground.

[0018] Preferably, in the laser-based Gantry Rubber Tyred Gantry Crane trolley speed control system,

[0019] The upper deceleration limit of the hoisting cam limit is used as the data reference point of the hoisting position encoder;

[0020] When the absolute value deviation between the data of the hoisting position encoder and the upper deceleration limit position data is greater than a predetermined value, the hoisting position encoder is cleared and reset.

[0021] Preferably, in the laser-based Gantry Rubber Tyred Gantry Crane trolley speed control system, when the signal of the spreader landing on the container and the locking signal exist at the same time, the PLC controller locks the current height value of the container area and compares it with the height value of the hoisting with container.

[0022] Preferably, in the laser-based Gantry Rubber Tyred Gantry Crane trolley speed control system, each laser receiver sends two acknowledgement signals to the PLC controller. Only when the PLC controller receives two acknowledgement signals, it is judged that there is no container at this height position.

[0023] Preferably, in the laser-based Gantry Rubber Tyred Gantry Crane trolley speed control system,

[0024] When it is determined that there is a container at a higher height position and no container at a lower height position, the PLC controller determines that there is a system failure and stops sending the command of full-speed driving to the trolley controller;

[0025] When the hoisting height value of the container detected by the hoisting position encoder gradually decreases, the PLC controller determines that the operation of discharging the container is being carried out and stops sending the command of full-speed driving to the trolley controller;

[0026] When the hoisting height value of the container detected by the hoisting position encoder remains at a certain height value, the PLC controller determines that the operation of transferring the container area is being carried out and stops sending the command of full-speed driving to the trolley controller.

[0027] The present invention has the following beneficial effects:

[0028] The spreader does not need to reach the highest position, and only needs to exceed the current container area height value to move forward at full speed, improving the operation efficiency of the rubber-tyred gantry crane;

[0029] As long as the PLC controller does not receive the confirmation signal, all are determined to have containers, and when the hoisting height of the container does not reach the current container area height value, the command of full-speed driving is not sent to the trolley controller, improving the reliability of the system;

[0030] Design multiple system stop conditions to avoid system errors from affecting the safety of the entire operation.

[0031] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of an embodiment of the laser-based trolley speed control system for a rubber-tyred gantry crane provided by the present invention;

[0033] Figure 2 It is a schematic laser position diagram of an embodiment of the laser-based trolley speed control system for a rubber-tyred gantry crane provided by the present invention;

[0034] Figure 3 It is a schematic diagram of the trolley moving at full speed in an embodiment of the laser-based trolley speed control system for a rubber-tyred gantry crane provided by the present invention;

[0035] Figure 4 It is a program diagram of the PLC controller in an embodiment of the laser-based trolley speed control system for a rubber-tyred gantry crane provided by the present invention;

[0036] Figure 5Another program diagram of the PLC controller in an embodiment of the laser-based gantry crane trolley speed control system provided by the present invention. Detailed implementation mode

[0037] The following further elaborates on the present invention in conjunction with the accompanying drawings, enabling those skilled in the art to implement it with reference to the text of the specification.

[0038] It should be understood that terms such as "having", "including", and "comprising" used herein do not preclude the presence or addition of one or more other elements or combinations thereof.

[0039] As Figure 1 shown, the present invention provides a laser-based gantry crane trolley speed control system, which includes:

[0040] A gantry crane body having a gantry support and a trolley moving on the crossbeam of the gantry support, the gantry support including a first column located downstream on the sea side and a second column located upstream on the land side;

[0041] A trolley controller electrically connected to the trolley and driving the trolley to travel;

[0042] A lifting position encoder for detecting the current lifting height value of the container with the box;

[0043] Three laser transmitters respectively arranged at a first height position, a second height position, and a third height position of the first column, the second height position being higher than the first height position, and the third height position being higher than the second height position;

[0044] Three laser receivers respectively arranged at a first height position, a second height position, and a third height position of the second column, and the laser receivers are arranged diagonally opposite to the laser transmitters and correspond one by one. The laser receivers receive the laser emission data emitted by the laser transmitters to form laser reception data, and perform CRC verification on it and the laser emission data. When the verification is correct, it is determined that there is no container between the laser transmitter and the laser receiver and a confirmation signal is sent;

[0045] A PLC controller communicatively connected to the trolley controller, the lifting position encoder, and the laser receiver; the PLC controller confirms the current height value of the container area according to the received confirmation signal. When the lifting height value of the container with the box is higher than the current height value of the container area, a full-speed driving command is sent to the trolley controller.

[0046] As Figure 2 shown, in an embodiment of the laser-based gantry crane trolley speed control system provided by the present invention,

[0047] The first height position is at 6.7 m above the ground;

[0048] The second height position is at 9.6 m above the ground;

[0049] The third height position is at 12.2 m above the ground.

[0050] In an embodiment of the laser-based gantry crane trolley speed control system provided by the present invention,

[0051] The upper deceleration limit of the hoisting cam limit is used as the data reference point of the hoisting position encoder;

[0052] When the absolute value deviation between the data of the hoisting position encoder and the upper deceleration limit position data is greater than a predetermined value, the hoisting position encoder is cleared and reset.

[0053] In an embodiment of the laser-based gantry crane trolley speed control system provided by the present invention, when the spreader landing signal and the locking signal exist simultaneously, the PLC controller locks the current height value of the container area and compares it with the hoisting height value with the container.

[0054] In an embodiment of the laser-based gantry crane trolley speed control system provided by the present invention, each laser receiver sends two confirmation signals to the PLC controller, and the PLC controller determines that there is no container at this height position only when it receives two confirmation signals.

[0055] In an embodiment of the laser-based gantry crane trolley speed control system provided by the present invention,

[0056] When it is determined that there is a container at a higher height position and no container at a lower height position, the PLC controller determines that the system has a fault and stops sending a full-speed driving command to the trolley controller;

[0057] When the hoisting height value with the container detected by the hoisting position encoder gradually decreases, the PLC controller determines that the container is being discharged and stops sending a full-speed driving command to the trolley controller;

[0058] When the hoisting height value with the container detected by the hoisting position encoder remains at a certain height value, the PLC controller determines that the container area is being transferred and stops sending a full-speed driving command to the trolley controller.

[0059] In the gantry crane trolley speed control system based on laser provided by the present invention, laser emission is carried out by using 3 laser transmitters, which emit laser data signals; laser reception is carried out by using 3 laser receivers, which receive laser data signals. One laser data transmitter corresponds to one laser receiver, and it adopts an open laser data transmission method. By using the characteristic that laser travels in a straight line and cannot be blocked, it detects the intermediate obstacle (box). That is, when the receiver receives a complete data signal, it is determined in the system that there is no obstacle, that is, no box, between the transmitter and the receiver; while when the receiver cannot receive the complete laser data from the transmitter, the system determines that there is an obstacle in the middle, that is, there is a box.

[0060] The transmitter and the receiver are respectively installed on the girder columns on the downstream side of the sea and the upstream side of the land of the gantry crane, and the height of the container in the container position of the gantry crane is detected in a diagonal detection manner. The installation heights are 6.7 meters, 9.6 meters, and 12.2 meters, corresponding to detecting three high-container heights, four container heights, and five high-container heights in the container area respectively, as shown in Table 1 specifically.

[0061] Table 1 Sensor Installation Position Height Confirmation Table

[0062] Number of boxes Height of standard box (m) Height of high box (m) Height of sensor (m) 1 0～2.6 0～2.9 2 2.6～5.2 2.9～5.8 3 5.2～7.8 5.8～8.7 6.7 4 7.8～10.4 8.7～11.6 9.6 5 10.4～13 11.6～14.5 12.2

[0063] The laser receiver will perform CRC verification on the received complete data. After the verification is correct, it will be decoded and an acknowledgment instruction will be output. When the data is interfered with or affected during the transmission process, the received data is incomplete, the verification cannot pass, and the data will be discarded without outputting an acknowledgment instruction. The acknowledgment instruction is output to the I / O module of the PLC in the electrical room of the gantry crane, and the PLC performs logical operation processing.

[0064] As Figure 3 shown, after the laser signal data passes the verification, an acknowledgment instruction is output to the PLC. After the PLC program performs logical operations to obtain the actual stacking situation of the containers in the container area, the precise positioning of the actual height of lifting with the container is realized through the hoisting position encoder, and it is compared with the operation signal of the actual container height. When the lifting height with the container is greater than the highest container in the container area and reaches the safe and optimal height, a full-speed instruction for the trolley is authorized. At the same time, in order to ensure the accuracy of the position encoder, the upper deceleration limit of the hoisting cam limit is used as the data reference point for comparing with the encoder data. That is, when the absolute value deviation between the encoder data and the upper deceleration limit position data is greater than a certain value, the program determines that the encoder has a deviation and needs to be cleared and reset.

[0065] During normal operation, since the laser signal changes in real time according to the increase and decrease of the boxes in the container yard, in order to ensure the locking of the laser signal during the lifting of the container, logical design is carried out in the PLC program. That is, when the signal of the spreader touching the box and the locking signal exist simultaneously, the actual box height data signal detected by the current laser signal in the container yard is locked and recognized as the current system working state. After that, the container can be lifted to perform normal height comparison. As Figure 4 shown, it is a program screenshot of the PLC controller. Among them, MB000411 and MB000412 respectively represent the two signals of "touching the box" and "locking". Only when these two signals exist simultaneously, it means that the current spreader just locks the box and is in the preparation stage for lifting. Then the subsequent detection start signal will be energized (DB00001). In this way, the basic pre-signals of the following three-layer box height (DB00002), four-layer box height (DB00003) and five-layer box height (DB00004) signals are available. Only at this time can the three box height signals be read respectively to perform subsequent data comparison.

[0066] To reduce the probability of safety problems caused by system failures, various failure situations are considered:

[0067] ① The laser emission device fails, no signal data is emitted, the receiving device does not receive data, and no confirmation instruction is output.

[0068] ② The laser receiving device fails and cannot receive signal data normally, and no confirmation instruction is output.

[0069] ③ During the laser transmission process, some data is lost, the received signal data is incomplete, and no confirmation instruction is output.

[0070] ④ The laser signal confirmation instruction transmission is interrupted.

[0071] ⑤ The laser receiving device misoutputs the signal confirmation instruction.

[0072] For the above-mentioned considered failure situations, the following protection design is adopted

[0073] Select the reverse signal, that is, in the program design, when the signal confirmation instruction is received, it is defaulted that there is no box at this box height; when the signal confirmation instruction is not received, it is defaulted that there is a box at this box height. Simply put, when the above 1-4 failure situations occur and the PLC program does not receive the confirmation instruction signal, regardless of whether there is actually a box at this box height in the container yard, the system determines that there is a box. When the lifting height does not exceed this box height, the full-speed movement of the trolley is not authorized.

[0074] When the 5th fault situation occurs, a three - layer protection design is adopted. The first layer of protection comes from inside the receiver. The output of the confirmation instruction is determined by the internal relay of the receiver. Two sets of contacts of the relay are used as interlocking protection. When an abnormal instruction output occurs, the internal processor of the receiver will handle it and disconnect the confirmation instruction. The second layer of protection is the external transmission of the confirmation instruction, which adopts a dual - signal mode, that is, 3 laser signals are used to output the confirmation instruction and 6 wires are used for transmission, with each signal using 2 wires simultaneously. On the I / O input module of the PLC, 2 modules are also used to input 3 signal points respectively. The internal design of the program compares the 2 input points of each signal. When one of the 2 parallel points of a certain signal point has an abnormality, the interlock designed in the program will stop the system from working and temporarily cancel this function. The third layer of protection is the "high - level detecting low - level" logic design in the program. That is, if the high - level signal (taking a 5 - layer high container as an example) detects that there is a box, but the low - level signal (three - layer or four - layer high) detects no box, the system will determine that there is a fault and forcefully stop this function.

[0075] As Figure 5 shown, starting from position 146 in the figure, the 4 - layer high signal is normally open and the 3 - layer high signal is normally closed. It is used to detect the logic between the 4 - layer high and the 3 - layer high. That is, when the 4 - layer high detects a container, the normally open signal of DB000037 is pulled in. At this time, according to the normal logic, there must also be a container on the 3 - layer high. Therefore, the 3 - layer high signal DB000036 must also be pulled in. Since it is set as a normally closed signal, when it is detected that there is no container on the 3 - layer high signal, the subsequent DB000040 coil is pulled in, which is recognized as a fault.

[0076] Similarly, starting from position 151, when it is detected that there is a container on the 5 - layer high, the 5 - layer high signal DB000035 is pulled in. At this time, both the 4 - layer high signal and the 3 - layer high signal must detect a container. DB000036 and DB000037 are both set as normally closed points to ensure that the DB000041 fault coil is not pulled in. If there is a 5 - layer high signal, but no container is detected on the 3 - layer high signal or the 4 - layer high signal, the normally closed contact conducts, and the DB00041 fault coil is pulled in.

[0077] In addition, two situations are designed for the system to automatically cancel the function. One is during the operation of lifting the container, when the driver makes a lowering action. At this time, the system believes that the driver has basically aligned with the position of the box and is about to perform the operation of placing the box. To prevent the trolley from hitting the box at full speed during the box - placing process, this function is automatically cancelled. The second is when the driver drives the container - carrying trolley for a certain distance. At this time, the system believes that the driver needs to transfer the box area. Since the signal captured is from the original box area and does not match the new box area, for safety reasons, the system automatically cancels the function.

[0078] It should be emphasized that no matter what kind of failure causes the system function to stop, it will not affect the normal operation of the equipment. Only this function stops temporarily, and the driver's operation automatically switches back to the original "door-shaped" mode.

[0079] According to the feedback from the operation department, before the transformation, the rear wheel crane could only have a fast movement of the trolley after the spreader was lifted to the highest position. Now, as long as the safety height is exceeded, it can move quickly, and the efficiency is significantly faster than before. The efficiency before the transformation was about 20 lifts per hour, and after the transformation, it can reach 25 lifts per hour. Under the condition of quite good site conditions, it can even reach about 28 lifts per hour. In addition, when lifting a container from a container truck and placing it on the outermost 1L (without stacking two or more containers in the middle), it used to take about 3 minutes to complete before the transformation, and now it only takes about 2 minutes to complete after the transformation, and the operation efficiency has been significantly improved.

[0080] The gantry crane trolley speed control system based on laser provided by the present invention is a practical project mainly aimed at increasing operation efficiency. On the basis of increasing operation efficiency, it can achieve a certain reduction in energy consumption and extend the service life of the wire rope. The box height in the container yard is detected by installing and fixing the position on the girder column, and its stability and reliability are good. Safety is emphasized in the overall design. It is better to stop the function and resume the "door-shaped" operation than to ensure that there are no safety accidents during the operation.

[0081] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the examples shown and described here.

Claims

1. Laser-based gantry crane trolley speed control system, characterized in that, Comprising: A gantry tire crane body, which has a gantry support and a trolley that travels on the crossbeam of the gantry support. The gantry support includes a first column located downstream on the sea side and a second column located upstream on the land side; A trolley controller, which is electrically connected to the trolley and drives the trolley to travel; A lifting position encoder, which is used to detect the current lifting height value of the container with the spreader; Three laser emitters, which are respectively arranged at the first height position, the second height position and the third height position of the first column. The second height position is higher than the first height position, and the third height position is higher than the second height position; Three laser receivers, which are respectively arranged at the first height position, the second height position and the third height position of the second column. And the laser receivers are arranged diagonally opposite to the laser emitters and correspond one by one. The laser receivers receive the laser emission data emitted by the laser emitters to form laser reception data, and perform CRC check on it and the laser emission data. When the check is correct, it is judged that there is no container between the laser emitter and the laser receiver and an acknowledgement signal is sent out; A PLC controller, which is communicatively connected to the trolley controller, the lifting position encoder and the laser receiver; The PLC controller confirms the current height value of the container area according to the received acknowledgement signal. When the lifting height value of the container with the spreader is higher than the current height value of the container area, it sends a full-speed driving command to the trolley controller; The first height position is at 6.7 m from the ground; The second height position is at 9.6 m from the ground; The third height position is at 12.2 m from the ground; Taking the upper deceleration limit of the lifting cam limit as the data reference point of the lifting position encoder; When the absolute value deviation between the data of the lifting position encoder and the data of the upper deceleration limit position is greater than a predetermined value, the lifting position encoder is cleared and reset.

2. The laser-based trolley speed control system for gantry tire cranes according to claim 1, wherein The PLC controller also locks the current height value of the container area and compares it with the lifting height value of the container with the spreader when the spreader landing signal and the locking signal exist simultaneously.

3. The laser-based gantry crane trolley speed control system according to claim 1, wherein Each of the laser receivers sends two acknowledgement signals to the PLC controller. Only when the PLC controller receives two acknowledgement signals, it is judged that there is no container at this height position.

4. The laser-based gantry tire crane trolley speed control system according to claim 1, wherein When it is judged that there is a container at a higher height position and no container at a lower height position, the PLC controller judges that the system has a fault and stops sending the full-speed driving command to the trolley controller; When the lifting height value of the container with the spreader detected by the lifting position encoder gradually decreases, the PLC controller judges that the container is being discharged and stops sending the full-speed driving command to the trolley controller; When the lifting height value of the container with the spreader detected by the lifting position encoder remains at a certain height value, the PLC controller judges that the container area is being transferred and stops sending the full-speed driving command to the trolley controller.

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