Online laser scanner and rapid detection method

Abstract

The present invention provides an online laser scanner and a rapid detection method. The laser scanner includes a support and a laser source. The support is provided with a prism that can rotate on vertical and horizontal axes. The laser scanner is connected to a lifting push rod, and the lifting push rod is fixedly mounted on the body of the container front loader. The laser scanner obtains the laser point cloud of the FTR lock; when it is determined that the lock cylinders of the four FTR locks are all visible, it is determined that the uncoupling is completed; if it is determined that at least one of the lock cylinders of the four FTR locks is not visible, it is determined that the uncoupling is not completed, and an alarm is triggered to cut off the power; through the above steps, the laser line scanner is used to detect whether the uncoupling is achieved. The present invention can use a laser scanner to detect the safety of container hoisting online, avoiding accidents that damage the loading compartment. In addition, the detection accuracy of the laser scanner is not affected by the tilt of the hoisting equipment and the imbalance of cargo loading in the container. The entire hoisting detection process is highly efficient, and the optimized algorithm improves detection efficiency while ensuring accuracy.

Description

Technical Field

[0001] The present invention relates to the field of laser scanning, in particular to an online laser scanner and a rapid detection method. Background Art

[0002] Reach-stack cranes are currently widely used in China for loading and unloading containers. FTR locks are installed at the four corners of the transport vehicle's surface, each with a beak that locks the container's corner fittings during lowering and lifting. In existing operations, reach-stack cranes have repeatedly encountered incidents where the FTR locks failed to disengage during unloading, causing the carriage to lift off the track. To overcome this problem, existing technologies employ laser detection to monitor the disengagement status. CN 114275678 A describes a method for rapidly releasing FTR locks on a gantry crane using a laser rangefinder. This method determines whether the disengagement is normal by measuring the distance between the spreader and the flatbed. In "Design of a Safety Monitoring System for FTR Lock Disengagement in Railway Containers," Shao Yuhua et al. propose installing an intelligent FTR lock disengagement detection system on the spreader. For example, four tension sensors or an inclination sensor can be installed on a dedicated spreader to determine whether the disengagement is normal. However, vibrations during the lifting process can lead to significant detection errors in the tension sensors. Due to the uneven loading of containers, the detection data of the laser rangefinder and inclination sensor are prone to inaccuracies during the lifting process. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an online laser scanner and a rapid detection method, which can use the laser scanner to scan the FTR lock and accurately determine whether the FTR lock has been unhooked. This can achieve rapid detection at a low cost and high speed.

[0004] In order to solve the above-mentioned technical problems, the technical solution of the present invention is: an online laser line scanner, the laser scanner includes a support and a laser source, the support is provided with a prism that can rotate along the vertical axis and the horizontal axis, the laser scanner is connected to the lifting push rod, and the lifting push rod is fixedly installed on the body of the container reach crane.

[0005] In a preferred embodiment, a DC motor is fixed on the support, the output shaft of the DC motor is connected to the fork-shaped bracket, the output shaft of the DC motor is in a vertical state, and a photoelectric sensor is also provided, the photoelectric sensor is used to detect the rotation angle of the fork-shaped bracket;

[0006] A stepper motor is fixed on the fork-shaped bracket, the output shaft of the stepper motor is connected to the prism, the end of the output shaft is also provided with a zero switch, the output shaft of the stepper motor is in a horizontal state, and the zero position of the zero switch is in a horizontal position.

[0007] In a preferred solution, four FTR locks are provided on the loading compartment, and the FTR locks are used to lock the four legs of the container. A reflective strip is provided at the position of the groove below the beak of the lock column of the FTR lock.

[0008] In a preferred solution, the laser scanner is located at a position on the front of the container reach stacker body facing the loading compartment, and the elevation of the laser scanner is substantially flush with the upper surface of the loading compartment.

[0009] In a preferred solution, the laser scanner is electrically connected to the PLC, the PLC is electrically connected to the industrial control machine, and the output of the laser scanner is electrically connected to the industrial control machine;

[0010] The PLC is electrically connected to a control device of a spreader of a container reach stacker crane.

[0011] In a preferred solution, the photoelectric sensor and the zero switch are electrically connected to the PLC, the PLC is electrically connected to the DC motor and the stepper motor, and a memory is also provided in the laser scanner, which is electrically connected to the industrial computer for transmitting the point cloud data to the industrial computer;

[0012] The industrial computer is electrically connected to the PLC, the PLC is electrically connected to a control device of a spreader of a container reach stacker crane, and the PLC is also electrically connected to a lifting push rod.

[0013] A rapid detection method using the above-mentioned online laser line scanner includes the following steps:

[0014] S1, power on the spreader;

[0015] S2, laser scanner starts;

[0016] S3: The laser scanner scans a certain range on the front to obtain the elevation position of the bottom of the container;

[0017] S4, the lifting push rod moves, driving the laser scanner to move up and down, so that the scanning center line of the laser scanner is flush with the bottom elevation of the container;

[0018] S5, PLC controls the speed and stroke limit of the spreader;

[0019] S6. The laser scanner scans within a preset range;

[0020] S7, laser scanner obtains laser point cloud of FTR lock;

[0021] S8. When it is determined that the lock cylinders of the four FTR locks are all visible, it is determined that the unhooking is completed;

[0022] If at least one of the four FTR lock cylinders is not visible, it is determined that the lock has not been unhooked, and the alarm is turned off;

[0023] Through the above steps, a laser line scanner can be used to quickly detect whether the hook is unhooked.

[0024] In a preferred solution, in step S3, the laser scanner scans to form at least three vertical scanning lines, and the elevation position of the bottom of the container is obtained according to the elevation of the breakpoint position at the top of the scanning line.

[0025] In a preferred solution, in step S7, brightness screening is performed in the collected laser point cloud according to a preset brightness threshold. Point cloud data exceeding the brightness threshold is marked as valid data, while point cloud data below the brightness threshold is marked as invalid data.

[0026] In the preferred solution, clustering operation is performed on the valid point cloud data according to the distance between the point cloud data and the laser scanner; in step S8, the cluster set is counted, and if the count is 4, it is determined that the decoupling is completed; if the count is a value other than 4, it is determined that the decoupling is not completed.

[0027] The present invention provides an online laser scanner and rapid detection method that can be used to monitor container lifting safety online, preventing accidents that could damage the loading compartment. Furthermore, the laser scanner's detection accuracy is unaffected by spreader tilt and uneven cargo loading within the container. The entire lifting detection process is highly efficient, and the use of an optimized algorithm significantly improves detection efficiency while ensuring accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the accompanying drawings and examples:

[0029] Figure 1 This is a schematic diagram of the local structure of the laser scanner of the present invention when detecting an FTR lock.

[0030] Figure 2 This is a top view of the container reach stacker crane of the present invention when it is working.

[0031] Figure 3 Schematic diagram of the structure of the laser scanner of the present invention.

[0032] Figure 4 This is a schematic diagram of obtaining the elevation position of the bottom of a container in the present invention.

[0033] Figure 5 This is a schematic diagram of scanning the FTR lock during the lifting process in the present invention.

[0034] Figure 6 Schematic diagram of the detection process of the present invention.

[0035] Figure 7 It is a block diagram of the control structure of the present invention.

[0036] In the figure: FTR lock 1, lock column beak 101, reflective strip 102, loading compartment 2, container 3, spreader 4, boom 5, container reach stacker 6, guide rail 7, laser scanner 8, support 81, DC motor 82, photoelectric sensor 83, fork bracket 84, stepper motor 85, prism 86, zero switch 87, lifting push rod 9, laser source 10, scanning line 11. DETAILED DESCRIPTION

[0037] Example 1:

[0038] like Figure 1 、 2 In the embodiment, an online laser line scanner is provided. The laser scanner 8 includes a support 81 and a laser source 10. The support 81 is provided with a prism 86 that can rotate on the vertical axis and the horizontal axis. The laser scanner 8 is connected to a lifting push rod 9, and the lifting push rod 9 is fixedly mounted on the body of the container front crane 6. The lifting push rod 9 preferably adopts an electric push rod. The electric push rod is based on a threaded structure to achieve lifting and lowering. It also has the function of self-locking in elevation. Usually, after adjusting the elevation once, there is no need to adjust the elevation again in the subsequent working process. With this structure, the online laser line scanner of the present invention can control the scanning plane to be flush with the bottom of the container 3. In the preferred embodiment, a vertical guide rail 7 is also provided, and the laser scanner 8 slides up and down along the guide rail 7.

[0039] The preferred solution is Figure 3 In the embodiment, a DC motor 82 is fixed to the support 81. The output shaft of DC motor 82 is connected to a fork-shaped support 84. The output shaft of DC motor 82 is in a vertical position and is used to drive fork-shaped support 84 to rotate along the vertical axis. A photoelectric sensor 83 is also provided. Photoelectric sensor 83 is used to detect the rotation angle of fork-shaped support 84. Photoelectric sensor 83 adopts a grating sensor to provide accurate feedback on the rotation angle of fork-shaped support 84. Preferably, in this embodiment, the rotation angle of fork-shaped support 84 is limited to 120 degrees from the front of laser scanner 8.

[0040] A stepper motor 85 is fixedly mounted on the fork-shaped bracket 84. The output shaft of the stepper motor 85 is connected to the prism 86. A zeroing switch 87 is also provided at the end of the output shaft. The output shaft of the stepper motor 85 is in a horizontal state, and the zero position of the zeroing switch 87 is in a horizontal position. The stepper motor 85 drives the prism 86 to rotate along the horizontal axis. In this example, the pitch angle is controlled within the range of ±10°. Preferably, the pitch angle is controlled within the range of ±5° to significantly reduce the amount of data collected. The stepper motor 85 adopts open-loop control. When the zeroing switch 87 sends a signal to the PLC, the PLC defines the rotation angle of the stepper motor 85 at that moment as 0°, thereby compensating for errors. At the same time, the complexity of the sensor is greatly reduced.

[0041] The preferred solution is Figure 2In the embodiment, four FTR locks 1 are provided on the loading compartment 2, and a lock column beak 101 is provided on the lock column of the FTR lock 1. The lock column beaks 101 of the two FTR locks 1 located at the left and right ends of the loading compartment 2 face in opposite directions. Therefore, during the process of lifting and unloading the container 3, the container 3 will rotate about 0.34° along the vertical axis. When the container 3 is lowered, the lock column beak 101 will lock the corner fittings of the container 3, thereby ensuring the safety of the container 3 during transportation. However, during the unloading process, after the sling 4 is connected to the top of the container 3, due to rust or deformation of the corner fittings of the container 3, the container 3 may not be able to be unhooked. There have been accidents in which the loading compartment 2 has derailed. Therefore, it is necessary to determine whether the unhooking of the container 3 is successful.

[0042] Preferably, a reflective strip 102 is provided at the position of the groove below the beak portion 101 of the lock cylinder of the FTR lock 1. The reflective strip 11 can obtain a brighter feedback signal, so that it is convenient to filter by brightness as the threshold during the acquisition of the laser point cloud, thereby greatly reducing the amount of calculation and improving the detection efficiency.

[0043] The preferred solution is Figure 2 In the figure, the laser scanner 8 is located at a position where the front of the container reach stacker 6 faces the loading compartment 2 , and the elevation of the laser scanner 8 is substantially flush with the upper surface of the loading compartment 2 .

[0044] The preferred solution is Figure 7 In the process, the laser scanner 8 is electrically connected to the PLC, the PLC is electrically connected to the industrial control machine, and the output of the laser scanner 8 is electrically connected to the industrial control machine;

[0045] The PLC is electrically connected to a control device of the spreader 4 of the container reach stacker 6 .

[0046] The preferred solution is Figure 7 In the figure, photoelectric sensor 83 and zero switch 87 are electrically connected to the input of the PLC, which is electrically connected to DC motor 82 and stepper motor 85. A memory is also provided within laser scanner 8, which is electrically connected to an industrial computer for transmitting collected point cloud data to the industrial computer. The industrial computer performs calculations to determine whether uncoupling has been achieved and then transmits the judgment result to the PLC. The industrial computer is electrically connected to the PLC, which is in turn electrically connected to the control device of the spreader 4 of the container reach stacker 6. Specifically, before uncoupling, the PLC controls the lifting stroke and lifting speed of the spreader 4. The PLC is also electrically connected to the lift push rod 9 to control its lifting motion.

[0047] Example 2:

[0048] like Figure 6 A rapid detection method using the above-mentioned online laser line scanner includes the following steps:

[0049] S1, spreader 4 is powered on;

[0050] S2, laser scanner 8 starts;

[0051] S3, such as Figure 4 In the process, the laser scanner 8 scans the front surface within a horizontal angle of 120° and a pitch angle of 5° to obtain the elevation position of the bottom of the container 3;

[0052] The preferred solution is Figure 4 Within the scanning range, at the left, center, and right positions, the laser scanner 8 forms at least three vertical scan lines 11, or three vertical point cloud data. Because the distance between the point cloud data and the laser scanner 8 varies significantly at the top surface of the loading compartment 2, the vertical point cloud data will have breakpoints at this location depending on the distance from the laser scanner 8. The elevation of the bottom of the container 3 can be determined based on the elevation of the top breakpoint of the scan line 11.

[0053] S4, such as Figure 1 In the process, the industrial computer calculates the difference between the elevation of the top breakpoint position of the scanning line 11 and the elevation of the laser scanner 8, obtains the lifting data of the laser scanner 8, and sends the lifting data to the PLC. The PLC converts the lifting data into the rotation angle of the motor of the lifting push rod 9 according to the pitch of the lifting push rod 9, and outputs the control parameters. The lifting push rod 9 moves to drive the laser scanner 8 to rise and fall, so that the scanning center line of the laser scanner 8 is roughly aligned with the bottom elevation of the container 3; usually, during the unloading operation of a vehicle, the lifting push rod 9 only needs to be adjusted once.

[0054] In S5, the PLC controls the speed and stroke of the spreader 4. PLC 16 primarily controls the speed of the spreader 4 by controlling the hydraulic system's solenoid valves and switching to flow-controlled pipelines. Alternatively, once the spreader 4 is properly connected to the container 3 and until a successful unlocking signal is received, PLC 16 performs all operations in a jog mode. This means that each operation only activates the solenoid valve once and then immediately deactivates it, effectively controlling the spreader 4 in a forced jog mode to improve operational safety. The travel of the spreader 4 is controlled by the angular travel of the boom 5 or the lifting stroke of the hydraulic cylinder. Steps S5 and S4 can be performed simultaneously to improve efficiency.

[0055] S6, such as Figure 5 In the process, the laser scanner 8 scans within a preset range; that is, it scans within a range of a front horizontal angle of 120° and a pitch angle of 5°.

[0056] S7, the laser scanner 8 obtains the laser point cloud of the FTR lock 1; preferably, it mainly obtains the laser point cloud data of the reflective strip 102. In the collected laser point cloud, brightness screening is first performed according to a preset brightness threshold. Point cloud data exceeding the brightness threshold is marked as valid data, while point cloud data below the brightness threshold is marked as invalid data. Since the brightness of the laser point cloud data of the reflective strip 102 is much higher than the brightness of other locations, and there is no interference from sunlight noise, it is easy to distinguish the laser point cloud data of the reflective strip 102 from other data. It should be noted that the collected point cloud data is first brightness screened before coordinate calculation, for example, it is screened according to the signal strength of the corresponding point, and only valid data is used to calculate the coordinate value parameters, such as the distance between the point and the coordinate origin and the z-axis coordinate of the point. The above scheme can greatly improve the efficiency of laser point cloud scanning assisted operation control.

[0057] S8, such as Figure 5 In the process, when it is determined that the lock cylinders of the four FTR locks 1 are all visible, it is determined that the unhooking is completed;

[0058] If it is determined that at least one of the lock cylinders of the four FTR locks 1 is not visible, it is determined that the lock has not been unhooked, and the alarm is turned off;

[0059] Through the above steps, a laser line scanner can be used to quickly detect whether the hook is unhooked.

[0060] The preferred solution is Figure 5In the process, the scanned points will form a point cloud similar to a rectangle. The distance between each point in the clustered point cloud and the origin of the laser scanner 8 is within a very small range. The effective point cloud data of each cluster is clustered according to the distance between the point and the laser scanner 8. Optionally, the clustering operation can also be performed according to the relative distance of the point cloud data. In the preferred solution, the set of clusters is counted. If the count is 4, it is judged that the decoupling is completed. If the count is a value other than 4, it is judged that the decoupling is not completed. In a further preferred solution, the number of points in the point cloud data of each cluster is verified. Only clustered point clouds with a number exceeding the preset value are included in the count, otherwise they are eliminated as noise points. With this solution, possible noise interference is avoided. In this example, the number of points in the point cloud data of each cluster is set to 8, that is, only point cloud data with more than 8 points are included in the count. With this solution, the amount of calculation is further reduced. In a further preferred solution, a centering operation is performed on the clustered point cloud data, and the coordinates of the midpoint in the clustered point cloud data are used as the coordinate values of the clustered point cloud data. The relative distance between the point cloud coordinate values of each cluster is calculated to determine whether it is within the range of the relative distance between the FTR locks 1. The verification here adopts a fuzzy algorithm, and the value of the relative distance is set to a range of intervals to verify whether the clustered point cloud data is the reflective strip 102 on the FTR lock 1. This solution can further improve the recognition accuracy without affecting the speed.

[0061] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The embodiments and features in the embodiments of this application may be arbitrarily combined with each other unless they conflict. The scope of protection of the present invention shall be the technical solutions described in the claims, including equivalent alternatives to the technical features of the technical solutions described in the claims. Equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. An online laser line scanner, characterized by: The laser scanner (8) includes a support (81) and a laser source (10). The support (81) is provided with a prism (86) that can rotate about a vertical axis and a horizontal axis. The laser scanner (8) is connected to a lifting push rod (9). The lifting push rod (9) is fixedly mounted on the body of the container reach crane (6). A DC motor (82) is fixedly provided on the support (81), and an output shaft of the DC motor (82) is connected to the fork-shaped support (84). The output shaft of the DC motor (82) is in a vertical state. A photoelectric sensor (83) is also provided. The photoelectric sensor (83) is used to detect the rotation angle of the fork-shaped support (84); A stepper motor (85) is fixed on the fork bracket (84), the output shaft of the stepper motor (85) is connected to the prism (86), and the end of the output shaft is also provided with a zero switch (87), the output shaft of the stepper motor (85) is in a horizontal state, and the zero position of the zero switch (87) is in a horizontal position; Four FTR locks (1) are provided on the loading compartment (2), and the FTR locks (1) are used to lock the four legs of the container (3). A reflective strip (102) is provided at the position of the groove below the beak portion (101) of the lock column of the FTR lock (1); The laser scanner (8) is located at a position where the front of the container reach stacker (6) faces the loading compartment (2), and the elevation of the laser scanner (8) is substantially flush with the upper surface of the loading compartment (2).

2. The online laser line scanner according to claim 1, wherein: The laser scanner (8) is electrically connected to the PLC, the PLC is electrically connected to the industrial control machine, and the output of the laser scanner (8) is electrically connected to the industrial control machine; The PLC is electrically connected to a control device of a spreader (4) of a container reach stacker crane (6).

3. The online laser line scanner according to claim 1, wherein: The photoelectric sensor (83) and the zeroing switch (87) are electrically connected to the PLC, and the PLC is electrically connected to the DC motor (82) and the stepper motor (85). A memory is also provided in the laser scanner (8), and the memory is electrically connected to the industrial control computer for transmitting the point cloud data to the industrial control computer. The industrial computer is electrically connected to the PLC, the PLC is electrically connected to a control device of a spreader (4) of a container reach crane (6), and the PLC is also electrically connected to a lifting push rod (9).

4. A rapid detection method using the online laser line scanner according to any one of claims 1 to 3, characterized in that The following steps are involved: S1, the spreader (4) is powered on; S2, laser scanner (8) starts; S3, the laser scanner (8) scans a certain range on the front side to obtain the elevation position of the bottom of the container (3); S4, the lifting push rod (9) moves to drive the laser scanner (8) to move up and down, so that the scanning center line of the laser scanner (8) is flush with the bottom elevation of the container (3); S5, PLC controls the speed and travel of the spreader (4); S6, the laser scanner (8) scans within a preset range; S7, laser scanner (8) obtains the laser point cloud of FTR lock (1); S8, when it is determined that the lock cylinders of the four FTR locks (1) are all visible, it is determined that the unhooking is completed; If it is determined that at least one of the lock cylinders of the four FTR locks (1) is not visible, it is determined that the lock is not unhooked, and the alarm is turned off; Through the above steps, a laser line scanner can be used to quickly detect whether the hook is unhooked.

5. The rapid detection method using an online laser line scanner according to claim 4 is characterized in that: In step S3, the laser scanner (8) scans to form at least three vertical scanning lines (11), and the elevation position of the bottom of the container (3) is obtained based on the elevation of the top breakpoint position of the scanning line (11).

6. The rapid detection method using an online laser line scanner according to claim 4 is characterized in that: In step S7, brightness screening is performed on the collected laser point cloud according to a preset brightness threshold. Point cloud data exceeding the brightness threshold is marked as valid data, while point cloud data below the brightness threshold is marked as invalid data.

7. The rapid detection method using an online laser line scanner according to claim 6, characterized in that: Performing clustering operation on valid point cloud data according to the distance between the point cloud data and the laser scanner (8); In step S8, the set of clusters is counted. If the count is 4, it is determined that the decoupling is completed. If the count is a value other than 4, it is determined that the decoupling is not completed.

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