Container positioning

Abstract

An arrangement for container positioning, comprising at least one infrared imaging means (60) configured to determine the position of a spreader (30) of a crane; at least one laser scanning means (50a,50b) configured to scan the area on which a container being handled is to be positioned and to determine a landing position for the container; wherein the at least one laser scanning means (50a,50b) is further configured to scan the spreader (30) and to determine the position thereof (30); and wherein the arrangement further comprises means for determining the difference between the position of the spreader (30) determined by the at least one infrared imaging means and the position of the spreader (30) determined by the at least one laser scanning means (50a,50b) and to correct the position of the spreader based on the determined difference.

Description

[0001] CONTAINER POSITIONING

[0002] TECHNICAL FIELD

[0003] The present disclosure generally relates to positioning containers. The disclosure relates particularly, though not exclusively, to positioning containers using automatic position detection. The disclosure relates particularly, though not exclusively, to positioning containers using laser scanning and infrared measurement.

[0004] BACKGROUND

[0005] This section illustrates useful background information without admission of any technique described herein representative of the state of the art.

[0006] Automated container cranes are widely used in cargo handling operations worldwide. For efficient operation, the position, for example on a trailer, on which the crane lands the container being handled needs to be accurately determined without disturbing the ongoing handling.

[0007] One of the challenges in operating automated container cranes is the calibration of the systems for determining the position. The calibration often requires special objects and markers, and expert personnel to perform the calibration at a required accuracy. This is especially the case when the measurement devices used are far from the target, which is often the case in automated stacking cranes, ASC, automated rubber-tired gantry cranes, ARTG and rail mounted gantry cranes, RMG.

[0008] Previously known solutions for position detection have employed for example cameras and reflectors. Such systems are known e.g. from publications EP3275831 B1 , US20050232733A1 and WO9607929A1.

[0009] There is a need for a solution with improved accuracy and ease of calibration of positioning containers in automatic truck handling at an ASC land side transfer zone. The present disclosure provides such a solution using 3D laser scanning and infrared imaging.

[0010] SUMMARY

[0011] The appended claims define the scope of protection. Any examples and technical descriptions of apparatuses, products and / or methods in the description and / or drawings not covered by the claims are presented not as embodiments of the invention but as background art or examples useful for understanding the invention. According to a first example aspect there is provided an arrangement for container positioning, comprising at least one infrared imaging means configured to determine the position of a spreader (30) of a crane; at least one laser scanning means configured to scan the area on which a container being handled is to be positioned and to determine a landing position for the container; wherein the at least one laser scanning means is further configured to scan the spreader and to determine the position thereof; and wherein the arrangement further comprises means for determining the difference between the position of the spreader determined by the at least one infrared imaging means and the position of the spreader determined by the at least one laser scanning means and to correct the position of the spreader based on the determined difference.

[0012] The at least one laser scanning means may comprise a 3D laser comprising a 2D laser scanner configured to be rotated using a motor for sweeping over the area to be scanned.

[0013] The at least one laser scanning means may be configured to determine the landing position by determining the position of at least one twistlock.

[0014] The at least one laser scanning means may be configured to determine the position of the spreader by determining the position of at least one reflective element on the spreader.

[0015] The at least one laser scanning means is configured to determine the position of the spreader by determining the position of several reflective elements on the spreader.

[0016] The at least one laser scanning means is configured to determine the position of the spreader by determining the position of several reflective elements positioned at each corner of the spreader.

[0017] The at least one reflective element comprises a flat portion and a triangular portion, wherein the flat portion is configured to function as a reference level and the triangular portion is configured to provide the position information, as the difference between the reflection from the flat portion and the triangular portion is at its largest at the peak of the reflector.

[0018] The at least one laser scanning means may be configured to scan the spreader and to determine the position thereof while a container is being hoisted.

[0019] According to a second example aspect there is provided a method for container positioning, comprising determining the position of a spreader of a crane with at least one infrared imaging means; scanning the area on which a container being handled is to be positioned with at least one laser scanning means and determining a landing position for the container; scanning the spreader and determining the position thereof with the at least one laser scanning means; determining the difference between the position of the spreader determined by the at least one infrared imaging means and the position of the spreader determined by the at least one laser scanning means; and correcting the position of the spreader based on the determined difference.

[0020] Determining a landing position for the container may comprise forming a point cloud of the area scanned with the at least one laser scanning means; determining local maxima; and using machine learning algorithms and geometry verification for determining the landing position from the point cloud data.

[0021] Scanning the spreader and determining the position thereof with the at least one laser scanning means may be carried out while the container is being hoisted.

[0022] The position of the spreader may be determined with the at least one laser scanning means and with at least one infrared imaging means, at least one of which means is also used to determine the landing position.

[0023] According to a third example aspect there is provided a control system for an automated container crane, comprising the arrangement of the first example aspect; and a control unit, comprising at least one memory comprising computer executable program code, and at least one processor configured cause the control system to cause carrying out, when executing the program code, the method of the second example aspect.

[0024] According to a fourth example aspect there is provided an automated container crane, comprising the arrangement of the first example aspect.

[0025] The automated container crane may be an automated stacking crane, ASC, an automated rubber-tired gantry crane, ARTG, or a rail mounted gantry crane, RMG.

[0026] According to a fifth example aspect there is provided a computer program comprising computer executable program code which when executed by the at least one processor of the control system of the third example aspect causes the control system to at least to perform the method of the second example aspect. According to a sixth example aspect there is provided a non-transitory memory medium, comprising the computer program of the fifth example aspect.

[0027] Different non-binding example aspects and embodiments have been illustrated in the foregoing. The embodiments in the foregoing are used merely to explain selected aspects or steps that may be utilized in different implementations. Some embodiments may be presented only with reference to certain example aspects. It should be appreciated that corresponding embodiments may apply to other example aspects as well.

[0028] BRIEF DESCRIPTION OF THE FIGURES

[0029] Some example embodiments will be described with reference to the accompanying figures, in which:

[0030] Fig. 1 schematically shows an automated container crane in accordance with an example embodiment;

[0031] Fig. 2 schematically shows a top view of a container landing position to be determined in accordance with an example embodiment;

[0032] Fig. 3 shows a spreader of an automated container crane in accordance with an example embodiment;

[0033] Fig. 4 shows an element of a spreader of an automated container crane in accordance with an example embodiment;

[0034] Fig. 5 shows a flow chart of a method in accordance with an example embodiment; and Fig. 6 shows a schematic block diagram of a control system according to an example embodiment.

[0035] DETAILED DESCRIPTION

[0036] In the following description, like reference signs denote like elements or steps.

[0037] Fig. 1 schematically shows an automated container crane 100 in accordance with an example embodiment. The automated container crane 100 comprises a girder 20 on which a trolley 10 is configured to move. A spreader 30 for lifting containers is connected to the trolley 10 in a conventional manner. Fig. 1 shows the spreader 30 connected directly to the trolley 10 via the ropes. Alternatively, the spreader 30 is releasably connected to a headblock (not shown) that is connected to the trolley via the ropes.

[0038] The automated container crane 100 comprises a container positioning arrangement according to an example embodiment, the arrangement comprising at least one laser scanning means 50a, 50b and at least one infrared imaging means 60. The at least one laser scanning means 50a, 50b, in an example embodiment, comprises a 3D laser comprising a 2D laser scanner configured to be rotated using a motor for sweeping over the area to be scanned. In an embodiment, the angle of the laser and the scan data is combined into a 3D point cloud presentation of the area being scanned.

[0039] In an embodiment, the container positioning arrangement comprises two laser scanning means 50a, 50b. In an embodiment, each laser scanning means 50a, 50b is configured to carry out a scanning swipe of one side of the container landing position, for example a trailer bed 40 for detecting the correct landing position for the container being handled.

[0040] The at least one infrared imaging means 60 comprises, in an embodiment, an infrared camera system configured to substantially continuously measure the position of the spreader 30, i.e. to provide a real time position of the spreader.

[0041] Fig. 2 schematically shows a container landing position to be determined in accordance with an example embodiment. Fig. 2 shows a trailer bed 40, comprising twistlocks 70a-d. The container positioning arrangement is configured to detect the positions of the container landing position, in an embodiment the position of the twistlocks using the at least one laser scanning means 50a, 50b carrying out a scanning sweep 52a, 52b of the sides of the trailer 40.

[0042] In an embodiment, the scanning sweep proceeds in the direction of the dashed lines 52a, 52b so that the motor turns the 2D laser scanner in a direction perpendicular to the dashed lines 52a, 52b. The speed of the 3D scan is dependent on the speed of the motor and the desired precision. In an embodiment, the area to be scanned is kept narrow, or a single laser scanning means has, in a further embodiment, a wider area to be scanned, for example the width of the whole trailer bed.

[0043] The laser scanning means 50a, 50b and the infrared imaging means 60 both provide accurate position information. In order to control the automated container crane 100 in efficient manner, the position information needs to be available in the same co-ordinate system, i.e. there is a to measure certain known points using both measurements, i.e. using both laser scanning and infrared imaging. In an embodiment, the position of the spreader 30 is determined by detecting the at least one reflective element 32a-d using both the infrared imaging means 60 and the at least one laser scanning means 50a, 50b, wherein the shared known points are the positions of the at least on reflective element 32a-d.

[0044] In an example embodiment, the infrared imaging means 60 and the at least one laser scanning means 50a, 50b are operated simultaneously, i.e. the position of the spreader 30 is determined with both means simultaneously. Fig. 3 shows a spreader 30 of an automated container crane in accordance with an example embodiment. In an example embodiment, the spreader 30 comprises at least one reflective element 32a-d the position of which is configured to be detected by the at least one laser scanning means 50a, 50b. In a further embodiment, the corners, edges and / or further elements on the spreader are configured to be detected by the at least one laser scanning means 50a, 50b. In an example embodiment, the precision of the position detection is improved by the spreader 30 comprising several reflective elements 32a-d and by positioning the reflective elements on a wide area on the spreader. In an example embodiment, the reflective elements 32a-d are positioned at each corner of the spreader, respectively, in a rectangular pattern thus providing the largest possible distances between the reflective elements 32a-d.

[0045] In an example embodiment, the several reflective elements 32a-d are positioned at a large distance from each other thus improving the accuracy of the position information. The positioning of the reflective elements 32a-d at each corner, or corner area, of the spreader provides the largest mutual distances possible. In an example embodiment, the reflective elements 32a-d are positioned above the spreader, so that any swaying of the container being moved has no possibility of damaging the reflective elements.

[0046] In an embodiment, the distances between the reflective elements 32c and 32a, or 32d and 32b respectively are known and accordingly a single scan by a single laser scanning means, can be performed by focusing only on one side of the container being handled, i.e. on a line along reflective elements 32c and 32d or 32a and 32b, respectively. In such a way, if redundancy is not a requirement, the measuring process takes less time. In a further embodiment, the at least one laser scanning means measure all reflective elements 32a- 32d and twistlocks 70a-70d. In a still further embodiment, the at least one laser scanning means 50a, 50b measure two reflective elements 32a-32b or 32c-3d along a lengthy side of the container and at least two of the four twistlocks 70a-70d.

[0047] Fig. 4 shows an example reflective element 32a of a spreader of an automated container crane in accordance with an example embodiment. The reflective element 32a comprises a flat portion 36 and a triangular portion 34. The flat portion 36 is configured to function as a reference level and the triangular portion is configured to provide the position information, as the difference d between the reflection from the flat portion 36 and the triangular portion 34 is at its largest at the peak of the reflector, the position thereof is accurately detected with the at least one laser scanning means 50a, 50b.

[0048] In an example embodiment, the reflective element 32a is aligned in such a way that the top of the triangular portion 34, i.e. the upper edge, is parallel with the long side of the spreader and the container. In an example embodiment, the top of the triangular element 36, i.e. the upper edge, is perpendicular to the girder 20 of the crane 100 in such a way that as the measurement sweeps proceed in the direction of the girder 20, i.e. traveling direction of the trolley 10, the sweep meets the triangular portion of the reflective element 32a-d from the side. Accordingly, the sideways position of the spreader is derivable from the sweep hitting any point of the triangular portion 34. The longitudinal position of the spreader is then determined from the step between the triangular portion 34 and the flat portion 36 or from the other end of the triangular portion 36.

[0049] In an example embodiment, the flat portions 36 of opposite reflective elements 32a-d point towards each other, i.e. the flat portions 36 are nearer to the center of the spreader.

[0050] In a further embodiment, the reflective elements 32a-d have a further form, for example for allowing a continuous position measurement with the laser scanning means 50a, 50b as well.

[0051] Fig. 5 shows a flow chart of a container positioning method in accordance with an example embodiment. In an example embodiment the container landing is automated based on the container positioning method. In a further embodiment, the container positioning method comprises providing a signal to an operator that the landing position has been determined, and the operator subsequently carries out, or approves, the final landing.

[0052] At step 510 the landing position for the container being handled is determined. The landing position is determined with the at least one laser scanning means 50a, 50b. In an embodiment, the landing area is scanned with the at least one laser scanning means 50a, 50b in order to form a point cloud of the scanned area. From the point cloud, local maxima are determined and using for example machine learning algorithms and geometry verification, the landing position is determined from the point cloud data.

[0053] At step 510, and continuously throughout the operation, the spreader position is measured using the infrared imaging means. Accordingly, the landing position is known from laser scanning and the position of the spreader, and therethrough of the container being handled is known from infrared imaging. At step 520, the container is being hoisted down towards the landing position. While hoisting the container down, the spreader position is determined using the at least on laser scanning means, i.e. in an embodiment the positions of the reflective elements 32a-d are determined. Simultaneously, the position of the reflectors is determined using the at least one infrared imaging means and thus the position of the reflectors has been measured with two systems, wherein at least one of the systems is also used to measure the landing position. In an example embodiment, the positions are determined from above using the at least one laser scanning means and the at least one infrared imaging means as shown in Figs. 1 and 2. In an example embodiment, the measurements are carried out continuously during hoisting.

[0054] At step 530 a difference between the position of the spreader determined with laser scanning and with infrared imaging is calculated. Both measurements are sensitive to changes in the position of the sensor, i.e. the at least one laser scanning means 50a, 50b and the at least one imaging means 60, especially if the system has not been recently calibrated. Accordingly, by calculating the difference between the positions determined, it is ascertained that the crane control system can land the container at the correct position.

[0055] As the position of the twistlocks 70a-d has been determined previously, the spreader and the container being handled covering the visibility to the twistlocks is not detrimental. Furthermore, the time during hoisting is used to calculate the difference between the position of the spreader determined with laser scanning and with infrared imaging and thus the time is saved as hoisting and position determination are carried out simultaneously.

[0056] At step 540 the spreader position is corrected based on the results of step 530 and the container is subsequently accurately positioned at the correct landing position.

[0057] Fig. 6 shows a schematic block diagram of a control system according to an example embodiment of the present invention. The control system is configured to control the container positioning arrangement according to example embodiments and the container positioning method according to example embodiments. The control system comprises a control unit 600 comprising a communication interface 610; a processor 620; a user interface 630; and a memory 640.

[0058] The communication interface 610 comprises in an embodiment a wired and / or wireless communication circuitry, such as Ethernet; Wireless LAN; Bluetooth; GSM; CDMA; WCDMA; LTE; and / or 5G circuitry. The communication interface can be integrated in the apparatus 600 or provided as a part of an adapter, card or the like, that is attachable to the apparatus 600. The communication interface 610 may support one or more different communication technologies. The control unit 600 may also or alternatively comprise more than one of the communication interfaces 610.

[0059] In this document, a processor may refer to a central processing unit (CPU); a microprocessor; a digital signal processor (DSP); a graphics processing unit; an application specific integrated circuit (ASIC); a field programmable gate array; a microcontroller; or a combination of such elements.

[0060] The user interface may comprise a circuitry for receiving input from a user of the control unit 600, e.g., via a keyboard; graphical user interface shown on the display of the control unit 600; speech recognition circuitry; or an accessory device; such as a headset; and for providing output to the user via, e.g., a graphical user interface or a loudspeaker.

[0061] The memory 640 comprises a work memory 642 and a persistent memory 644 configured to store computer program code 646 and data 648. The memory 640 may comprise any one or more of: a read-only memory (ROM); a programmable read-only memory (PROM); an erasable programmable read-only memory (EPROM); a random-access memory (RAM); a flash memory; a data disk; an optical storage; a magnetic storage; a smart card; a solid- state drive (SSD); or the like. The control unit 600 may comprise a plurality of the memories 640. The memory 640 may be constructed as a part of the control unit 600 or as an attachment to be inserted into a slot; port; or the like of the control unit 600 by a user or by another person or by a robot. The memory 640 may serve the sole purpose of storing data or be constructed as a part of a control unit 600 serving other purposes, such as processing data.

[0062] A skilled person appreciates that in addition to the elements shown in Figure 6, the control unit 600 may comprise other elements, such as microphones; displays; as well as additional circuitry such as input / output (I / O) circuitry; memory chips; application-specific integrated circuits (ASIC); processing circuitry for specific purposes such as source coding / decoding circuitry; channel coding / decoding circuitry; ciphering / deciphering circuitry; and the like. Additionally, the control unit 600 may comprise a disposable or rechargeable battery (not shown) for powering the control unit 600 if external power supply is not available.

[0063] The control unit 600 is in an embodiment a stand-alone control unit. In a further embodiment the control unit 600 is comprised in or integrated with another control arrangement, such as a crane control system, or a control system of a container terminal. In a further embodiment, the control unit 600 is situated in a cloud-based service. In a still further embodiment, the control unit is integrated with a personal computing device such as a laptop, tablet computer or a smartphone.

[0064] The control system of Fig. 6 in an embodiment further comprises the at least one laser scanning means 50a, 50b and the at least one infrared imaging means according to the embodiments described hereinbefore.

[0065] Without in any way limiting the scope of the appended claims, some technical effects of the system according to example embodiment of the invention are explained in the following.

[0066] The arrangement and method according to example embodiments is configured to enable more accurate container positioning.

[0067] Accordingly, a technical effect of example embodiment of the invention is enabling accurate positioning without or with lessened need for calibration. A further technical effect of the example embodiments of the invention is to allow continuous operation without stopping the spreader. A still further technical effect of the example embodiments of the invention is further automation of crane operations. A still further technical effect of the example embodiments of the invention is energy saving. A still further technical effect of the example embodiments is faster container handling.

[0068] Various embodiments have been presented. It should be appreciated that in this document, words comprise; include; and contain are each used as open-ended expressions with no intended exclusivity.

[0069] The foregoing description has provided by way of non-limiting examples of particular implementations and embodiments a full and informative description of the best mode presently contemplated by the inventors for carrying out the invention. It is however clear to a person skilled in the art that the invention is not restricted to details of the embodiments presented in the foregoing, but that it can be implemented in other embodiments using equivalent means or in different combinations of embodiments without deviating from the characteristics of the invention.

[0070] Furthermore, some of the features of the afore-disclosed example embodiments may be used to advantage without the corresponding use of other features. As such, the foregoing description shall be considered as merely illustrative of the principles of the present invention, and not in limitation thereof. Hence, the scope of the invention is only restricted by the appended patent claims.

Claims

CLAIMS1 .An arrangement for container positioning, comprising at least one infrared imaging means (60) configured to determine the position of a spreader (30) of a crane; at least one laser scanning means (50a, 50b) configured to scan the area on which a container being handled is to be positioned and to determine a landing position for the container; characterized in that the at least one laser scanning means (50a, 50b) is further configured to scan the spreader (30) and to determine the position thereof (30); wherein the arrangement further comprises means for determining the difference between the position of the spreader (30) determined by the at least one infrared imaging means and the position of the spreader (30) determined by the at least one laser scanning means (50a, 50b) and to correct the position of the spreader based on the determined difference.

2. The arrangement of claim 1 , wherein the at least one laser scanning means (50a, 50b) comprises a 3D laser comprising a 2D laser scanner configured to be rotated using a motor for sweeping over the area to be scanned.

3. The arrangement of claim 1 or 2, wherein the at least one laser scanning means (50a, 50b) is configured to determine the landing position by determining the position of at least one twistlock.

4. The arrangement of any preceding claim 1 - 3, wherein the at least one laser scanning means (50a, 50b) is configured to determine the position of the spreader (30) by determining the position of at least one reflective element (32a-d) on the spreader.

5. The arrangement of claim 4, wherein the at least one laser scanning means (50a, 50b) is configured to determine the position of the spreader (30) by determining the position of several reflective elements (32a-d) on the spreader.

6. The arrangement of claim 4 or 5, wherein the at least one laser scanning means (50a, 50b) is configured to determine the position of the spreader (30) by determining the position of several reflective elements (32a-d) positioned at each corner of the spreader.

7. The arrangement of any preceding claim 4-6, wherein the at least one reflective element (32a-d) comprises a flat portion (36) and a triangular portion (34), wherein the flat portion (36) is configured to function as a reference level and the triangular portion (34) is configured to provide the position information, as the difference between the reflection from the flat portion (36) and the triangular portion (34) is at its largest at the peak of the reflector.

8. The arrangement of any preceding claim 1 - 7, wherein the at least one laser scanning means (50a, 50b) is configured to scan the spreader (30) and to determine the position thereof (30) while a container is being hoisted.

9. A method for container positioning, comprising determining the position of a spreader (30) of a crane with at least one infrared imaging means (60); scanning the area on which a container being handled is to be positioned with at least one laser scanning means (50a, 50b) and determining a landing position for the container; scanning the spreader (30) and determining the position thereof (30) with the at least one laser scanning means (50a, 50b); determining the difference between the position of the spreader (30) determined by the at least one infrared imaging means and the position of the spreader (30) determined by the at least one laser scanning means (50a, 50b); and correcting the position of the spreader based on the determined difference.

10. The method of claim 9, wherein determining a landing position for the container comprises forming a point cloud of the area scanned with the at least one laser scanning means (50a, 50b); determining local maxima; and using machine learning algorithms and geometry verification for determining the landing position from the point cloud data.11 . The method of claim 9 or 10, wherein scanning the spreader (30) and determining the position thereof (30) with the at least one laser scanning means (50a, 50b) is carried out while the container is being hoisted.

12. The method of any preceding claim 9 - 11 , wherein the position of the spreader is determined with the at least one laser scanning means (50a, 50b) and with at least one infrared imaging means (60), at least one of which means is also used to determine the landing position.

13. A control system for an automated container crane, comprising the arrangement of any preceding claim 1 - 8; and a control unit, comprising at least one memory comprising computer executable program code, and at least one processor configured cause the control system to cause carrying out, when executing the program code, the method of any preceding claim 9 - 12.

14. An automated container crane, comprising the arrangement of any preceding claim 1 - 8.

15. The automated container crane of claim 14, wherein the automated container crane is an automated stacking crane, ASC, an automated rubber-tired gantry crane, ARTG, or a rail mounted gantry crane, RMG.

16. A computer program comprising computer executable program code which when executed by the at least one processor of the control system of claim 13 causes the control system to at least to perform the method of any preceding claim 9 -12.

17. A non-transitory memory medium, comprising the computer program of claim 16.

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