IGV fusion positioning method and system based on UHF RFID communication

Abstract

The invention provides an IGV fusion positioning method based on UHF RFID communication, and the method comprises the steps: arranging a plurality of positioning columns, and arranging four UHF RFID reader-writers, a laser radar scanner, a visual camera, and a vehicle-mounted information processing system; upright post positioning coordinate information of each positioning upright post is measured, and an RFID tag is arranged; scanning and identifying RFID tags on positioning upright posts around the IGV body, and transmitting a plurality of signal strength indication values and upright post positioning coordinate information to a vehicle-mounted information processing system; laser scanning is carried out on a positioning stand column near the IGV, so that laser identification stand column point cloud data is obtained, and then the laser identification stand column point cloud data is transmitted to a vehicle-mounted information processing system; positioning columns near the IGV are shot to obtain visual positioning data, and the visual positioning data are transmitted to a vehicle-mounted information processing system; and carrying out matching fusion to obtain real-time positioning coordinates of the IGV. The invention provides an IGV fusion positioning system based on UHF RFID communication. According to the invention, IGV navigation in a port is more accurate, reliable and stable.

Description

Technical Field

[0001] The present invention relates to the technical field of port unmanned vehicle communication and positioning, and in particular to an IGV fusion positioning method and system based on UHF RFID communication. Background Art

[0002] There are three main types of loading and unloading equipment in automated container terminals, namely, quay cranes for shore loading and unloading, rail cranes for yard loading and unloading, and horizontal transportation equipment for shuttling within the terminal, of which IGV is the main application equipment for horizontal transportation equipment. In automated container terminals, mission scenarios include automatic interaction between IGV and quay cranes, automatic interaction between IGV and rail cranes, interaction between IGV and charging system, mutual position confirmation between IGVs, and human-machine interaction for IGV disassembly and assembly locks. To ensure the safe and efficient operation of the equipment, these complex operation scenarios place higher requirements on the positioning accuracy of IGV. Therefore, for autonomous driving vehicles, the positioning stability of the vehicle itself is a key technical point.

[0003] The existing positioning system of autonomous driving vehicles is a fusion positioning system based on the global positioning system, which has the following disadvantages:

[0004] 1. The global positioning system relies on reference stations and complex solutions, and the equipment is expensive and difficult to maintain;

[0005] 2. The global positioning system is easily affected by the ground of the terminal, the quay crane, the height of the container stacking or the atmospheric ionosphere, resulting in signal obstruction and interference;

[0006] 3. The laser positioning system and visual positioning system cannot obtain initial positioning when the global positioning system signal fails. Summary of the invention

[0007] In view of this, it is necessary to propose an IGV fusion positioning method and system based on UHF RFID communication to address the above problems, so as to overcome some shortcomings in the above-mentioned background technology, thereby solving the technical problem of how to make IGV navigation in the port more accurate and reliable by integrating laser, vision and UHF-RFID.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention proposes an IGV fusion positioning method based on UHF RFID communication, which is applied to an automated container terminal where a plurality of IGVs are arranged. The IGV fusion positioning method comprises the following steps:

[0010] Step S1, multiple positioning columns are arranged at the automated container terminal, and four UHF RFID readers, a laser radar scanner, a visual camera and an on-board information processing system are installed on the IGV; the four UHF RFID readers are respectively located at the left front corner, right front corner, left rear corner and right rear corner of the IGV;

[0011] Step S2, measuring the column positioning coordinate information of each positioning column, and setting an RFID tag for recording the column positioning coordinate information on the positioning column one by one;

[0012] Step S3, using two diagonal UHF RFID readers of the IGV to scan and identify the RFID tags on the positioning pillars around the IGV body in real time, so that the UHF RFID reader obtains multiple signal strength indication values ​​corresponding to different frequencies of the corresponding RFID tags and the pillar positioning coordinate information, and transmits the multiple signal strength indication values ​​and the pillar positioning coordinate information to the vehicle information processing system; and using a laser radar scanner to perform laser scanning on the positioning pillars near the IGV to obtain laser identification pillar point cloud data, and then transmit the laser identification pillar point cloud data to the vehicle information processing system; and using a visual camera to shoot the positioning pillars near the IGV to obtain visual positioning data, and then transmit the visual positioning data to the vehicle information processing system;

[0013] In step S4, the vehicle information processing system matches and integrates the column positioning coordinate information, the laser recognition column point cloud data, the visual positioning data, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system to obtain the real-time positioning coordinates of the IGV.

[0014] Furthermore, the IGV fusion positioning method further includes the following steps between step S2 and step S3:

[0015] Step S23, coordinate mapping of the automated container terminal is performed by using a plurality of total stations, thereby forming a two-dimensional electronic map of the automated container terminal, and storing the two-dimensional electronic map in the vehicle-mounted information processing system.

[0016] Furthermore, in step S4, the real-time positioning coordinates of the IGV are estimated and corrected by a Kalman filter algorithm, thereby obtaining a corrected real-time accurate position of the IGV.

[0017] Further, in step S3, when two diagonal UHF RFID readers of the IGV fail to perform real-time scanning and identification of RFID tags on the positioning pillars around the IGV body, the other two diagonal UHF RFID readers of the IGV replace the two diagonal UHF RFID readers that failed to perform identification, and then the other two diagonal UHF RFID readers of the IGV continue to perform real-time scanning and identification of RFID tags on the positioning pillars near the IGV;

[0018] When the other two diagonal UHF RFID readers of the IGV still fail to scan and identify the RFID tag on the positioning column near the IGV in real time, the maintenance personnel are notified to perform maintenance.

[0019] Further, step S4 includes the following sub-steps:

[0020] Step S41, matching and fusing the column positioning coordinate information with the laser recognition column point cloud data to obtain laser navigation positioning information;

[0021] The column positioning coordinate information is matched and integrated with the visual positioning data to obtain visual navigation positioning information;

[0022] In step S42, the laser navigation positioning information obtained in step S41, the visual navigation positioning information obtained in step S41, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system are matched.

[0023] Furthermore, when the UHF RFID reader transmits a signal, the distance D between the RFID tag and the UHF RFID reader is obtained by determining at least three RFID tags and according to the signal strength reflected back by each RFID tag; wherein the three RFID tags identified by the UHF RFID reader form a triangle, i.e., they are not collinear.

[0024] Furthermore, in step S3, the distance from the IGV to several RFID tags is used to solve the equation group to obtain the reader coordinates (X, Y); the standard form of the equation group is: (Xn-X)2+(Yn-Y)2=Dn2, where Xn and Yn represent the RFID tag coordinates, and Dn represents the distance recognized by the RFID tag; the reader coordinates (X, Y) are solved according to the standard form of the equation group and through Python's three-circle intersection code program.

[0025] The present invention further proposes an IGV fusion positioning system based on UHF RFID communication, which is applied to an IGV. The IGV travels in an automated container terminal including a plurality of positioning columns, each of which is equipped with an RFID tag in a one-to-one correspondence. The IGV fusion positioning system includes:

[0026] On-board information processing system; the on-board information processing system includes an on-board computer, a laser scanning identification information processor, a visual identification information processor and a UHF RFID information processor; the on-board computer is installed with an IGV navigation correction software module, the laser scanning identification information processor is installed with a laser positioning software module, the visual identification information processor is installed with a visual identification software module, and the UHF RFID information processor is installed with a UHF RFID information processing software module; the on-board computer is respectively connected to the laser scanning identification information processor, the visual identification information processor and the UHF RFID information processor for communication; a laser radar scanner; the laser radar scanner is used to perform laser scanning on the positioning columns near the IGV, thereby obtaining the laser identification column point cloud data, and then transmitting the laser identification column point cloud data to the laser scanning identification information processor;

[0027] Visual camera: The visual camera is used to photograph the positioning pillars near the IGV to obtain visual positioning data, and then transmit the visual positioning data to the visual recognition information processor;

[0028] Four UHF RFID readers are installed at four corners of the IGV respectively; the UHF RFID information processor is connected to the four UHF RFID readers respectively; the UHF RFID reader is used to scan and identify the RFID tags on the positioning columns around the IGV body in real time, so as to obtain a plurality of signal strength indication values ​​corresponding to different frequencies of the corresponding RFID tags and the column positioning coordinate information, and transmit the plurality of signal strength indication values ​​and the column positioning coordinate information to the laser scanning recognition information processor via the UHF RFID information processor and the on-board computer in sequence, and transmit the plurality of signal strength indication values ​​and the column positioning coordinate information to the visual recognition information processor via the UHF RFID information processor and the on-board computer;

[0029] The laser positioning software module is used to match and fuse the designated column positioning coordinate information with the laser recognition column point cloud data according to the signal strength indication value received by the laser scanning recognition information processor, thereby obtaining the laser navigation positioning information, and then transmitting the laser navigation positioning information to the IGV navigation correction software module;

[0030] The visual recognition software module is used to match and fuse the designated column positioning coordinate information with the visual positioning data according to the signal strength indication value received by the visual recognition information processor, thereby obtaining visual navigation positioning information, and then transmitting the visual navigation positioning information to the IGV navigation correction software module;

[0031] The IGV navigation correction software module is used to match the received laser navigation positioning information, visual navigation positioning information, and the two-dimensional electronic map of the automated container terminal to obtain the real-time positioning coordinates of the IGV.

[0032] Furthermore, the IGV navigation correction software module is provided with a Kalman filter algorithm, which is used to estimate and correct the real-time positioning coordinates of the IGV, thereby obtaining the real-time accurate position of the IGV after correction;

[0033] The two-dimensional electronic map is obtained by performing coordinate mapping of the automated container terminal by a plurality of total stations, and the two-dimensional electronic map is stored in the IGV navigation correction software module.

[0034] The present invention further proposes a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the IGV fusion positioning method based on UHF RFID communication as described in any one of the above items are implemented.

[0035] The beneficial effects of the present invention are:

[0036] The present invention makes the IGV navigation in the port more accurate, reliable and stable by integrating laser, vision and UHF-RFID, solves the problem of failure of the global positioning system signal of the IGV self-vehicle fusion positioning system during the horizontal transportation task of the IGV, and also solves the problem of abnormal positioning caused by the inability of the IGV to obtain the initial positioning through laser positioning or visual positioning, that is, it overcomes the disadvantage that the IGV laser positioning system cannot obtain the initial positioning when the global positioning system signal fails, overcomes the disadvantage that the IGV visual positioning system cannot obtain the initial positioning when the global positioning system signal fails, and solves the problem that the stability of the recognition and matching of the IGV's laser positioning system is affected by factors such as equipment movement, obstruction of reference objects or changes in the position of containers in the yard, thereby improving the self-vehicle positioning stability of the IGV during horizontal transportation operations.

[0037] Advantages of this solution:

[0038] 1. The use of UHF RFID communication technology reduces investment costs, makes tags and readers easy to deploy, and makes subsequent maintenance simple;

[0039] Second, the use of UHF RFID communication technology can make the reading distance farther and the range wider through ultra-high frequency electromagnetic waves and phased array antennas, and realize the simultaneous identification of multiple objects;

[0040] 3. It is less affected by the on-site equipment and environmental factors of the automated terminal, and the signal transmission and reception are more reliable and stable;

[0041] 4. Data is implanted into each positioning column to facilitate the acquisition of initial positioning values ​​during laser positioning and improve the robustness of fusion positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description, are used to explain the principles of the present invention. These drawings are for illustration only and are not intended to limit the present invention.

[0043] Figure 1 It is a working flow chart of the IGV fusion positioning method based on UHF RFID communication of the present invention;

[0044] Figure 2 It is a principle structure block diagram of the IGV fusion positioning system based on UHF RFID communication of the present invention;

[0045] Figure 3 It is a schematic diagram of the three-dimensional structure of a positioning column with an RFID tag installed thereon according to the present invention;

[0046] Figure 4 This is a top view structural diagram of an IGV with four UHF RFID readers installed according to the present invention;

[0047] Figure 5 This is a top view of the working principle diagram of the IGV equipped with four UHF RFID readers and writers involved in the present invention in conjunction with the positioning column;

[0048] Figure 6 A schematic diagram of coordinate positioning when an IGV equipped with four UHF RFID readers according to the present invention detects multiple positioning columns;

[0049] Figure 7 This is a schematic diagram of the IGV fusion positioning output process based on UHF RFID communication according to Example 4 of the present invention;

[0050] Figure 8 This is a schematic diagram of the workflow of automatic switching of four UHF RFID readers in Example 4 of the present invention. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further clearly and completely described in combination with the embodiments of the present invention. It should be noted that 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 making creative work are within the scope of protection of the present invention.

[0052] The terms "first", "second", "third", "fourth", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the definition of "first", "second", "third", "fourth" features may explicitly or implicitly include one or more of the features.

[0053] The following is a detailed description of an embodiment of the invention depicted in the accompanying drawings. The embodiments are detailed in order to clearly convey the invention. However, the number of details provided is not intended to limit the intended variations of the embodiments; on the contrary, the intention is to cover all modifications, equivalents, and substitutes that fall within the spirit and scope of the invention as defined by the appended claims.

[0054] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.

[0055] Embodiments of the present invention include various steps, which are described below. These steps can be performed by hardware components, or can be contained in machine executable instructions, which can be used for general or special purpose processors programmed with instructions to perform these steps. Alternatively, the steps can be performed by a combination of hardware, software and firmware and / or a human operator.

[0056] The various methods described herein can be practiced by combining one or more machine-readable storage media containing codes according to the present invention with appropriate standard computer hardware to execute the codes contained therein. Apparatus for implementing various embodiments of the present invention may include one or more computers (or one or more processors within a single computer) and a storage system containing or having network access to computer programs encoded according to the various methods described herein, and the method steps of the present invention may be completed by modules, routines, subroutines or sub-parts of a computer program product.

[0057] If the specification states that a component or feature "may," "could," "might," or "might" include or have a feature, that particular component or feature is not required to be included or have that feature.

[0058] As used in the specification herein and the claims that follow, the meanings of “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

[0059] Exemplary embodiments will now be described more fully below with reference to the accompanying drawings, in which exemplary embodiments are shown. These exemplary embodiments are provided for illustrative purposes only, and so that the present invention is thorough and complete, and the scope of the present invention is fully conveyed to those of ordinary skill in the art. However, the disclosed invention can be implemented in many different forms and should not be interpreted as being limited to the embodiments set forth herein. Various modifications are apparent to those skilled in the art. Without departing from the spirit and scope of the present invention, the general principles defined herein can be applied to other embodiments and applications. In addition, all statements of the embodiments of the present invention and their specific examples described herein are intended to cover their structural and functional equivalents. In addition, these equivalents are intended to include currently known equivalents and equivalents developed in the future (i.e., any element developed to perform the same function, regardless of the structure). Moreover, the terms and wording used are for the purpose of describing exemplary embodiments and should not be considered restrictive. Therefore, the present invention will be given the widest scope, including multiple replacements, modifications and equivalents consistent with the disclosed principles and features. For the sake of clarity, the details of the technical materials known in the technical field related to the present invention are not described in detail, so as not to unnecessarily obscure the present invention.

[0060] Therefore, for example, it will be understood by those of ordinary skill in the art that schematic diagrams, schematic diagrams, diagrams, etc. represent conceptual views or processes that embody the systems and methods of the present invention. The functions of the various elements shown in the figures can be provided by using dedicated hardware and hardware capable of executing related software. Similarly, any switches shown in the figures are only conceptual. Their functions can be performed by the operation of program logic, by dedicated logic, by the interaction of program control and dedicated logic, or even manually, and specific techniques can be selected by the entity that implements the present invention. It will be further understood by those of ordinary skill in the art that the exemplary hardware, software, processes, methods and / or operating systems described herein are for illustrative purposes and are therefore not intended to be limited to any specific named elements.

[0061] Embodiments of the present invention may be provided as a computer program product, which may include a machine-readable storage medium on which instructions are tangibly implemented, which may be used to program a computer (or other electronic device) to perform a process. The term "machine-readable storage medium" or "computer-readable storage medium" includes, but is not limited to, fixed (hardware) drives, tapes, floppy disks, optical disks, optical disk read-only memories (CD-ROMs)) and magneto-optical disks, semiconductor memories such as ROMs, PROMs, random access memories (RAMs), programmable read-only memories (PROMs), erasable PROMs (EPROMs), electrically erasable PROMs (EEPROMs), flash memory, magnetic or optical cards, or other types of media / machine-readable media suitable for storing electronic instructions (e.g., computer programming code, such as software or firmware). Machine-readable media may include non-transitory media in which data may be stored and does not include carrier waves and / or transient electronic signals propagated by wireless or wired connections. Examples of non-transitory media may include, but are not limited to, disks or tapes, optical storage media such as compact disks (CDs) or digital versatile disks (DVDs), flash memory, memory or memory devices. A computer program product may include code and / or machine executable instructions, which may represent any combination of a process, function, subprogram, program, routine, subroutine, module, software package, class, or instruction, data structure, or program statement. A code segment may be coupled to another code segment or a hardware circuit by passing and / or receiving information, data, variables, parameters, or memory contents. Information, variables, parameters, data, etc. may be passed, forwarded, or transmitted by any suitable means, including memory sharing, message passing, token passing, network transmission, etc.

[0062] In addition, the embodiments may be implemented by hardware, software, firmware, middleware, microcode, hardware description language, or any combination thereof. When implemented in software, firmware, middleware, or microcode, the program code or code segments (e.g., computer program products) that perform the necessary tasks may be stored in a machine-readable medium. A processor may perform the necessary tasks.

[0063] The systems depicted in some of the figures may be provided in various configurations. In some embodiments, the system may be configured as a distributed system, where one or more components of the system are distributed over one or more networks in a cloud computing system.

[0064] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer only to certain specific embodiments. In other cases, it should be recognized that references to the "invention" will refer to the subject matter recited in one or more, but not necessarily all, of the claims.

[0065] Unless otherwise specified herein or the context is clearly contradictory, all methods described herein can be performed in any suitable order. The use of any and all examples or exemplary language (e.g., "such as") provided with respect to certain embodiments herein is intended only to better illustrate the present invention, rather than to limit the scope of the claimed invention. Any language in the specification should not be interpreted as indicating any unclaimed element essential to the implementation of the present invention.

[0066] Various terms used herein are listed below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the relevant art have given that term as reflected in printed publications and issued patents at the time of filing the application.

[0067] Example 1

[0068] like Figure 1 , Figure 3-Figure 6 As shown:

[0069] This embodiment proposes an IGV fusion positioning method based on UHF RFID communication, which is applied to an automated container terminal where a plurality of IGVs are deployed. The IGV fusion positioning method includes the following steps:

[0070] Step S1, multiple positioning columns are arranged at the automated container terminal, and four UHF RFID readers, a laser radar scanner, a visual camera and an on-board information processing system are installed on the IGV; the four UHF RFID readers are respectively located at the left front corner, right front corner, left rear corner and right rear corner of the IGV;

[0071] Step S2, measuring the column positioning coordinate information of each positioning column, and setting an RFID tag for recording the column positioning coordinate information on the positioning column one by one; specifically, the column positioning coordinate information refers to the column positioning coordinate information measured by a total station (a high-precision measuring instrument used in various engineering and surveying and mapping projects). Since the column and the RFID tag are installed at the same position, it is also the column positioning coordinate information of the RFID tag, and then the information is manually input into the RFID tag;

[0072] Step S3, using two diagonal UHF RFID readers of the IGV to scan and identify the RFID tags on the positioning pillars around the IGV body in real time, so that the UHF RFID reader obtains multiple signal strength indicator values ​​RSSI corresponding to different frequencies of the corresponding RFID tags and the pillar positioning coordinate information, and transmits the multiple signal strength indicator values ​​RSSI and the pillar positioning coordinate information to the vehicle information processing system; and performing laser scanning on the positioning pillars near the IGV by using a laser radar scanner to obtain laser identification pillar point cloud data, and then transmitting the laser identification pillar point cloud data to the vehicle information processing system; and photographing the positioning pillars near the IGV by using a visual camera to obtain visual positioning data, and then transmitting the visual positioning data to the vehicle information processing system;

[0073] In step S4, the vehicle information processing system matches and integrates the column positioning coordinate information, the laser recognition column point cloud data, the visual positioning data, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system to obtain the real-time positioning coordinates of the IGV.

[0074] Optimally, it is characterized in that the IGV fusion positioning method further includes the following steps between step S2 and step S3:

[0075] Step S23 (step S23 is executed after step S2), coordinate mapping of the automated container terminal is performed by using a plurality of total stations, thereby forming a two-dimensional electronic map of the automated container terminal, and the two-dimensional electronic map is stored in the vehicle-mounted information processing system; then step S3 is executed.

[0076] Optimally, in step S4, the real-time positioning coordinates of the IGV are estimated and corrected by a Kalman filter algorithm, thereby obtaining the corrected real-time accurate position of the IGV.

[0077] Optimally, in step S3, when two diagonal UHF RFID readers of the IGV fail to perform real-time scanning and identification of RFID tags on the positioning pillars around the IGV body, the other two diagonal UHF RFID readers of the IGV replace the two diagonal UHF RFID readers that failed to perform identification, and then the other two diagonal UHF RFID readers of the IGV continue to perform real-time scanning and identification of RFID tags on the positioning pillars near the IGV;

[0078] When the other two diagonal UHF RFID readers of the IGV still fail to scan and identify the RFID tag on the positioning column near the IGV in real time, the maintenance personnel are notified to perform maintenance.

[0079] Optimally, step S4 includes the following sub-steps:

[0080] Step S41, matching and fusing the column positioning coordinate information with the laser recognition column point cloud data to obtain laser navigation positioning information;

[0081] The column positioning coordinate information is matched and integrated with the visual positioning data to obtain visual navigation positioning information; then step S42 is executed;

[0082] In step S42, the laser navigation positioning information obtained in step S41, the visual navigation positioning information obtained in step S41, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system are matched.

[0083] Specifically, the antenna of the UHF RFID reader / writer adopts a phase array antenna.

[0084] Optimally, when the UHF RFID reader transmits a signal, the distance D between the RFID tag and the UHF RFID reader is obtained by determining at least three RFID tags and according to the signal strength reflected back by each RFID tag; wherein the three RFID tags identified by the UHF RFID reader form a triangle, i.e., they are not collinear.

[0085] Optimally, in step S3, the distance from the IGV to several RFID tags is used to solve the equation group to obtain the reader coordinates (X, Y); the standard form of the equation group is: (Xn-X)2+(Yn-Y)2=Dn2, where Xn and Yn represent the RFID tag coordinates, and Dn represents the distance recognized by the RFID tag; the reader coordinates (X, Y) are solved according to the standard form of the equation group and through Python's three-circle intersection code program.

[0086] Example 2

[0087] like Figure 2-Figure 6 As shown:

[0088] An IGV fusion positioning system based on UHF RFID communication is applied to an IGV, which travels in an automated container terminal including a plurality of positioning columns, each positioning column being equipped with an RFID tag one by one. The IGV fusion positioning system includes:

[0089] On-board information processing system; the on-board information processing system includes an on-board computer, a laser scanning identification information processor, a visual identification information processor and a UHF RFID information processor; the on-board computer is installed with an IGV navigation correction software module, the laser scanning identification information processor is installed with a laser positioning software module, the visual identification information processor is installed with a visual identification software module, and the UHF RFID information processor is installed with a UHF RFID information processing software module; the on-board computer is respectively communicated with the laser scanning identification information processor, the visual identification information processor and the UHF RFID information processor;

[0090] Laser radar scanner; the laser radar scanner is used to perform laser scanning on the positioning columns near the IGV, thereby obtaining laser recognition column point cloud data, and then transmitting the laser recognition column point cloud data to the laser scanning recognition information processor;

[0091] Visual camera: The visual camera is used to photograph the positioning pillars near the IGV to obtain visual positioning data, and then transmit the visual positioning data to the visual recognition information processor;

[0092] Four UHF RFID readers are installed at four corners of the IGV respectively; the UHF RFID information processor is connected to the four UHF RFID readers respectively; the UHF RFID reader is used to scan and identify the RFID tags on the positioning columns around the IGV body in real time, so as to obtain multiple signal strength indicator values ​​RSSI corresponding to different frequencies of the corresponding RFID tags and the column positioning coordinate information, and transmit the multiple signal strength indicator values ​​RSSI and the column positioning coordinate information to the laser scanning recognition information processor via the UHF RFID information processor and the on-board computer in sequence, and transmit the multiple signal strength indicator values ​​RSSI and the column positioning coordinate information to the visual recognition information processor via the UHF RFID information processor and the on-board computer;

[0093] The laser positioning software module is used to match and fuse the designated column positioning coordinate information with the laser recognition column point cloud data according to the signal strength indicator RSSI received by the laser scanning recognition information processor, thereby obtaining the laser navigation positioning information, and then transmitting the laser navigation positioning information to the IGV navigation correction software module;

[0094] The visual recognition software module is used to match and fuse the designated column positioning coordinate information with the visual positioning data according to the signal strength indicator RSSI received by the visual recognition information processor, thereby obtaining visual navigation positioning information, and then transmitting the visual navigation positioning information to the IGV navigation correction software module;

[0095] The IGV navigation correction software module is used to match the received laser navigation positioning information, visual navigation positioning information, and the two-dimensional electronic map of the automated container terminal to obtain the real-time positioning coordinates of the IGV.

[0096] Optimally, the IGV navigation correction software module is provided with a Kalman filter algorithm, which is used to estimate and correct the real-time positioning coordinates of the IGV, thereby obtaining the real-time accurate position of the IGV after correction;

[0097] The two-dimensional electronic map is obtained by performing coordinate mapping of the automated container terminal by a plurality of total stations, and the two-dimensional electronic map is stored in the IGV navigation correction software module.

[0098] Further optimized, the IGV fusion positioning system based on UHF RFID communication of this embodiment executes the IGV fusion positioning method based on UHF RFID communication as described in any technical solution in Example 1.

[0099] Example 3

[0100] This embodiment proposes a computer-readable storage medium, which stores a computer program, characterized in that when the computer program is executed by a processor, the steps of the IGV fusion positioning method based on UHF RFID communication as described in any technical solution of Example 1 are implemented.

[0101] Example 4

[0102] Embodiment 4 is a further optimization and improvement based on embodiment 2;

[0103] like Figure 1-Figure 8 As shown:

[0104] Optimally, the laser positioning software module is specifically a laser navigation system, which identifies the coordinates (X, Y) of positioning columns, such as positioning columns at the boundary of the yard, positioning columns of the fence, etc.

[0105] Optimally, RFID tags are installed on all positioning columns of the automated terminal, and the coordinates (X, Y) of the corresponding positioning columns are written into the RFID tags.

[0106] Optimally, UHF RFID readers are installed at the four corners of the IGV, and the data cables are connected to the on-board computer to achieve data connectivity; usually only R1 and R3 (diagonal) UHF RFID readers are open, and installing four is a redundant design to ensure that another pair of UHF RFID readers can be switched for positioning in time in case of failure.

[0107] Optimally, when the IGV is turned on and running in the automated terminal yard, the UHF RFID reader will scan and identify the RFID tags on the positioning columns around the IGV body in real time; since the UHF RFID reader transmits multi-frequency signals, the UHF RFID reader can obtain multiple RSSI (signal strength indication) values ​​corresponding to the different frequencies of each tag.

[0108] Optimally, the UHF RFID reader uploads the RSSI value information of the RFID tag and the stored coordinate information to the on-board computer. The on-board computer converts the RSSI value difference into a distance difference, and calculates the distance from the antenna to each RFID tag together with the coordinate information, thereby determining the positioning coordinates in the UHF RFID positioning system (i.e., the UHF RFID information processing software module).

[0109] Optimally, the onboard computer sends the positioning coordinates of the IGV's UHF RFID positioning system to the laser positioning system, which combines the received positioning coordinates, the laser recognition column point cloud data and the built-in Figure 3 The coordinates of the laser positioning system are calculated by matching them.

[0110] Optimally, the onboard computer sends the IGV's UHF RFID positioning system positioning coordinates to the visual positioning system (i.e., visual recognition software module). The visual positioning system uses the received positioning coordinates, the visual camera to identify the ground marker data, and the built-in ground Figure 3 The real-time positioning coordinates of IGV are calculated by matching.

[0111] Optimally, the on-board computer fuses the column positioning coordinate information (i.e., RFID positioning data), laser recognition column point cloud data (i.e., laser positioning data) and visual positioning data, estimates and corrects the position through the Kalman filter algorithm, and outputs high-precision position information.

[0112] The specific algorithm is as follows: the UHF RFID reader transmits a signal, and the distance D between the tag and the UHF RFID reader is obtained according to the signal strength reflected by each RFID tag. The UHF RFID reader mounted on the IGV can determine its own coordinates by determining at least three tags (which are required to form a triangle, i.e., not collinear). The more tags are determined, the more accurate its own coordinates are; Figure 5 As shown, first, if we know the distance from a point on a plane to tags A, B, and C, to determine the location of the point, we only need to draw a circle and find the intersection point; we can solve the equations by the distance from the IGV to several tags, and thus calculate the coordinates (X, Y) of the IGV reader. The standard form of the equations is:

[0113] (X n -X)2 +(Y n -Y) 2 =D n 2

[0114] Where X n and Y n represents the RFID tag coordinates, D n Indicates the distance that the RFID tag can recognize.

[0115] Then, we use Python to help solve the UHF RFID reader coordinates (X, Y) according to the standard form, where the three circles find the intersection code, the radius R of the center coordinates of the first circle (x0, y0), the radius N of the center coordinates of the second circle (e, f), and the radius P of the third circle.

[0116] Specifically, the coordinate position of the UHF RFID reader is obtained in the same way as the coordinates of the other diagonal UHF RFID reader. Assuming that the coordinates of any pair of diagonal UHF RFID readers are (X1, Y1) and (X2, Y2), the vehicle center position algorithm is: X = (X1 + X2) / 2, Y = (Y1 + Y2) / 2, and finally the IGV coordinates (X, Y) are obtained.

[0117] Specifically, the UHF RFID reader uses a phased array antenna; a phased array antenna is also called a phased array antenna, and its basic principle is to change the shape of the radiation pattern by controlling the feeding phase of the radiating unit in the array antenna; phased array antennas are generally divided into linear phased arrays and planar phased arrays, both of which are based on phase control technology; a planar phased array antenna consists of multiple antenna units arranged in a certain pattern on a surface, and each antenna unit has independent phase and amplitude control functions; when the planar phased array antenna is working, the phase and amplitude of each antenna unit are precisely adjusted by a computer or other control system to achieve control of the beam direction; specifically, by adjusting the phase difference between different antenna units, the signal radiated by the antenna can form a wave in a specific direction in space. beam; when the phase difference changes, the direction of the beam will also deflect accordingly, thereby realizing the scanning of the beam in a two-dimensional plane; in addition, the planar phased array antenna can also control the beam shape by adjusting the amplitude distribution of different antenna units, such as changing the beam width, gain and other parameters; when the planar phased array antenna is working, it can be regarded as a single-port reader becoming a multi-port reader (there are as many ports as there are phase combinations). The original single-port reader can only connect to one antenna with a fixed radiation range, while the multi-port reader can connect to many antennas, and each antenna has a different radiation range. This multi-port reader can select the area to be scanned according to demand and start the corresponding port to transmit the signal, and cover the specified area through the corresponding antenna.

[0118] Specifically, the UHF RFID reader / writer involves UHF RFID multi-point positioning technology. The coverage area of ​​the UHF RFID reader / writer is a circle, with a total of n sectors and N radiation areas. It can be simply understood as an N-port reader connected to antennas in N different radiation areas. In actual applications, adjacent numbered radiation areas overlap with each other. When the same RFID tag is identified in multiple numbered radiation areas, the specific location of the RFID tag can be calculated by the RSSI value.

[0119] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An IGV fusion positioning method based on UHF RFID communication is applied to an automated container terminal where several IGVs are arranged, characterized in that: The IGV fusion positioning method comprises the following steps: Step S1, multiple positioning columns are arranged at the automated container terminal, and four UHF RFID readers, a laser radar scanner, a visual camera and an on-board information processing system are installed on the IGV; the four UHF RFID readers are respectively located at the left front corner, right front corner, left rear corner and right rear corner of the IGV; Step S2, measuring the column positioning coordinate information of each positioning column, and setting an RFID tag for recording the column positioning coordinate information on the positioning column one by one; Step S3, using two diagonal UHF RFID readers of the IGV to scan and identify the RFID tags on the positioning pillars around the IGV body in real time, so that the UHF RFID reader obtains multiple signal strength indicator values ​​(RSSI) corresponding to different frequencies of the corresponding RFID tags and the pillar positioning coordinate information, and transmits the multiple signal strength indicator values ​​(RSSI) and the pillar positioning coordinate information to the vehicle information processing system; and using a laser radar scanner to perform laser scanning on the positioning pillars near the IGV, so as to obtain laser identification pillar point cloud data, and then transmit the laser identification pillar point cloud data to the vehicle information processing system; and using a visual camera to shoot the positioning pillars near the IGV, so as to obtain visual positioning data, and then transmit the visual positioning data to the vehicle information processing system; In step S4, the vehicle information processing system matches and integrates the column positioning coordinate information, the laser recognition column point cloud data, the visual positioning data, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system to obtain the real-time positioning coordinates of the IGV.

2. The IGV fusion positioning method based on UHF RFID communication according to claim 1 is characterized in that: The IGV fusion positioning method also includes the following steps between step S2 and step S3: Step S23, coordinate mapping of the automated container terminal is performed by using a plurality of total stations, thereby forming a two-dimensional electronic map of the automated container terminal, and storing the two-dimensional electronic map in the vehicle-mounted information processing system.

3. The IGV fusion positioning method based on UHF RFID communication according to claim 1 is characterized in that: In step S4, the real-time positioning coordinates of the IGV are estimated and corrected by a Kalman filter algorithm, thereby obtaining the corrected real-time accurate position of the IGV.

4. The IGV fusion positioning method based on UHF RFID communication according to claim 1 is characterized in that: In step S3, when two diagonal UHF RFID readers of the IGV fail to perform real-time scanning and identification of RFID tags on the positioning pillars around the IGV body, the other two diagonal UHF RFID readers of the IGV replace the two diagonal UHF RFID readers that failed to perform identification, and then the other two diagonal UHF RFID readers of the IGV continue to perform real-time scanning and identification of RFID tags on the positioning pillars near the IGV; When the other two diagonal UHF RFID readers of the IGV still fail to scan and identify the RFID tag on the positioning column near the IGV in real time, the maintenance personnel are notified to perform maintenance.

5. The IGV fusion positioning method based on UHF RFID communication according to claim 1 is characterized in that: Step S4 includes the following sub-steps: Step S41, matching and fusing the column positioning coordinate information with the laser recognition column point cloud data to obtain laser navigation positioning information; And match and fuse the column positioning coordinate information with the visual positioning data to obtain visual navigation positioning information; In step S42, the laser navigation positioning information obtained in step S41, the visual navigation positioning information obtained in step S41, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system are matched.

6. The IGV fusion positioning method based on UHF RFID communication according to any one of claims 1 to 5, characterized in that: When the UHF RFID reader transmits a signal, the distance D between the RFID tag and the UHF RFID reader is obtained by determining at least three RFID tags and according to the signal strength reflected back by each RFID tag; wherein the three RFID tags identified by the UHF RFID reader form a triangle, i.e., they are not collinear.

7. The IGV fusion positioning method based on UHF RFID communication according to any one of claims 1 to 5, characterized in that: In step S3, the distance from the IGV to several RFID tags is used to solve the equation group to obtain the reader coordinates (X, Y); the standard form of the equation group is: (Xn-X)2+(Yn-Y)2=Dn2, where Xn and Yn represent the RFID tag coordinates, and Dn represents the distance recognized by the RFID tag; the reader coordinates (X, Y) are solved according to the standard form of the equation group and the Python three-circle intersection code program.

8. An IGV fusion positioning system based on UHF RFID communication, characterized in that: Applied to IGV, the IGV travels in an automated container terminal including multiple positioning columns, each positioning column is equipped with an RFID tag one by one. The IGV fusion positioning system includes: On-board information processing system; the on-board information processing system includes an on-board computer, a laser scanning identification information processor, a visual identification information processor and a UHF RFID information processor; the on-board computer is installed with an IGV navigation correction software module, the laser scanning identification information processor is installed with a laser positioning software module, the visual identification information processor is installed with a visual identification software module, and the UHF RFID information processor is installed with a UHF RFID information processing software module; the on-board computer is respectively communicated with the laser scanning identification information processor, the visual identification information processor and the UHF RFID information processor; Laser radar scanner; the laser radar scanner is used to perform laser scanning on the positioning columns near the IGV, thereby obtaining laser recognition column point cloud data, and then transmitting the laser recognition column point cloud data to the laser scanning recognition information processor; Visual camera: The visual camera is used to photograph the positioning pillars near the IGV to obtain visual positioning data, and then transmit the visual positioning data to the visual recognition information processor; Four UHF RFID readers are installed at four corners of the IGV respectively; the UHF RFID information processor is connected to the four UHF RFID readers respectively; the UHF RFID reader is used to scan and identify the RFID tags on the positioning columns around the IGV body in real time, so as to obtain multiple signal strength indication values ​​(RSSI) corresponding to different frequencies of the corresponding RFID tags and the column positioning coordinate information, and transmit the multiple signal strength indication values ​​(RSSI) and the column positioning coordinate information to the laser scanning recognition information processor via the UHF RFID information processor and the on-board computer in turn, and transmit the multiple signal strength indication values ​​(RSSI) and the column positioning coordinate information to the visual recognition information processor via the UHF RFID information processor and the on-board computer; The laser positioning software module is used to match and fuse the designated column positioning coordinate information with the laser recognition column point cloud data according to the signal strength indicator value (RSSI) received by the laser scanning recognition information processor, so as to obtain the laser navigation positioning information, and then transmit the laser navigation positioning information to the IGV navigation correction software module; The visual recognition software module is used to match and fuse the designated column positioning coordinate information with the visual positioning data according to the signal strength indicator value (RSSI) received by the visual recognition information processor, so as to obtain the visual navigation positioning information, and then transmit the visual navigation positioning information to the IGV navigation correction software module; The IGV navigation correction software module is used to match the received laser navigation positioning information, visual navigation positioning information, and the two-dimensional electronic map of the automated container terminal to obtain the real-time positioning coordinates of the IGV.

9. The IGV fusion positioning system based on UHF RFID communication according to claim 8, characterized in that: The IGV navigation correction software module is equipped with a Kalman filter algorithm, which is used to estimate and correct the real-time positioning coordinates of the IGV, thereby obtaining the real-time accurate position of the IGV after correction; The two-dimensional electronic map is obtained by performing coordinate mapping of the automated container terminal by a plurality of total stations, and the two-dimensional electronic map is stored in the IGV navigation correction software module.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the IGV fusion positioning method based on UHF RFID communication as described in any one of claims 1 to 7 are implemented.

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