Automatic path finding method for OHT track

Abstract

The invention provides an automatic path-finding method for an OHT track. The automatic path-finding method comprises the OHT track and a path-finding vehicle, and the path-finding vehicle runs on the OHT track. An RFID card reader, a first recognizer and a second recognizer are arranged on the road-finding vehicle; a walking label and a storage position label are arranged on the OHT track; the running mode of the road finding vehicle comprises the following steps: S1, initializing a system; s2, the RFID card reader on the path finding vehicle reads the walking tag; s3, the first recognizer finds a potential storage position; the path finding vehicle moves to the position of the storage position label and stops; s4, in the parking state, a second recognizer is started to read the storage position label; s5, calculating and recording position information of the walking label and the current storage position label; and S6, generating binding relation data. According to the invention, active parking at the storage position is adopted, and then accurate measurement is carried out, so that the finally obtained'walking label-storage position 'binding distance data reaches millimeter-level precision.

Description

Technical Field

[0001] This invention relates to the technical field of semiconductor devices, and more specifically, to an automatic pathfinding method for an OHT (Optical Path Tunneling Device). Background Technology

[0002] In modern semiconductor wafer fabs, the efficiency and reliability of material handling systems directly affect the overall production performance of the plant. Overhead hoist transport (OHT) is the core equipment for handling wafer carriers (FOUPs) within the factory, and its operational accuracy on the dense track network is crucial.

[0003] The navigation and positioning of the OHT system relies on a tagging system laid along the track. The tagging system includes several types of tags: travel tags: placed at equal intervals or key nodes above the track, and OHT obtains its own coarse-grained location information by reading these tags; storage location tags: placed at various storage points below the track to accurately locate specific cargo locations.

[0004] When the OHT receives a command to move to a target location (storage location), it typically first locates itself within the range of a certain travel tag, then starts from the reference point of the travel tag, moves precisely a certain distance, stops accurately directly above the storage location tag, and completes the code reading.

[0005] For example, after receiving the command "Place FOUP in A10 Port", OHT first determines the barcode number of "A10 Port" (e.g., "70000"), then determines which running tag's jurisdiction "A10 Port" is approximately located in (e.g., near running tag "12822"), and finally determines the precise distance (e.g., 722mm) to move from the reference point of running tag "12822" to stop directly above "A10 Port" to complete the barcode reading.

[0006] "Storage Location Tag ID - Associated Travel Tag ID - Precise Distance Value" is the storage location map used in OHT's automated operation. However, after new line construction, track expansion, or maintenance, the map data is often missing or inaccurate. Therefore, an automated "pathfinding" mechanism is needed to collect and generate this crucial binding relationship data. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0008] Therefore, this invention proposes an automatic pathfinding method for OHT tracks, which includes an OHT track and a pathfinding vehicle, with the pathfinding vehicle running on the OHT track; The exploration vehicle is equipped with: an RFID card reader, a first identifier, and a second identifier; The OHT track is equipped with travel tags and storage location tags; The operation mode of the exploration vehicle includes the following steps: Step S1: System initialization, the scout vehicle travels along the OHT track; Step S2: The RFID reader on the exploration vehicle reads the travel tag and records the travel tag ID and current location information; Step S3: The first identifier detects a potential storage location below the track; the exploration vehicle moves to the storage location tag and stops or moves at a low, constant speed. Step S4: In the docked state or in low-speed uniform motion, the second identifier is activated to read the storage location tag and obtain the storage location tag ID and type; Step S5: Calculate and record the distance from the nearest walking tag to the current storage tag, as well as the location information of the walking tag and the current storage tag; Step S6: Associate and bind the travel tag ID, storage location tag ID, storage location type, location information, and distance information to generate binding relationship data.

[0009] Preferably, the OHT track is equipped with a reflective strip, and the first identifier includes a reflective identifier. The reflective strip is set at a first fixed distance in front of the storage label. In step S3, after the first identifier detects the reflective strip, it predicts that there is a potential storage space behind it. The exploration vehicle starts to decelerate, moves a first fixed distance, stops, and starts to activate the second identifier.

[0010] Preferably, the OHT track is provided with a reflective strip, and the first identifier includes a reflective identifier. The reflective strip is set at a second fixed distance behind the travel label. After the first identifier detects the reflective strip, it corrects the position of the travel label, accurately positions it, and records it.

[0011] Preferably, the second identifier includes a barcode reader, and the storage location label includes a Port label or a UTB label, wherein the Port label or UTB label is a barcode label, and the second identifier scans and identifies the Port label or UTB label.

[0012] Preferably, the second recognizer includes a QR code reader, and the storage location label includes an OHB label, which is a QR code label, and the second recognizer scans and recognizes the OHB label.

[0013] Preferably, the first recognizer also includes a visual sensor, and when the QR code graphic is detected, the QR code reader reads the code.

[0014] Preferably, the second identifier is a barcode reader, which uses a global shutter and high-frequency triggering to capture continuous images. The barcode reader is equipped with a high-precision encoder and an image recognition system. The high-precision encoder obtains the precise position of each frame of the image in real time. The image recognition system determines which frame of the image has the clearest label and the most correct position, and uses the encoder position corresponding to that frame as the optimal positioning point for the label. In step S4, the exploration vehicle moves at a low and uniform speed, with a speed of less than 0.1 m / s.

[0015] Preferably, in step S4, the second identifier is a barcode reader, which uses a high-speed imaging device to capture continuous images; the barcode reader is equipped with a high-precision encoder and an image recognition system, and the high-precision encoder obtains the precise position of each frame of image in real time when it is captured. The first identifier includes at least a reflective identifier. After detecting the reflective strip, it records the location of the reflective strip. At the same time, the exploration vehicle begins to decelerate. The distance between the reflective strip and the storage location tag is a first fixed distance. The specific operating steps are as follows: Step S41: The scout vehicle begins to decelerate from the location of the reflective strip; Step S42: Based on the first fixed distance, predict the location of the storage location tag; Step S43: The scout vehicle takes a high-speed photo of the barcode reader 5-10cm before reaching the estimated location of the storage tag. Step S44: The exploration vehicle stops at the estimated location of the storage location tag and takes pictures; Step S45: The exploration vehicle moves forward slowly again by 5-10cm, while the barcode reader takes a high-speed photo. Step S46: Use the image recognition system to determine which frame of the image has the clearest label and the most correct position, and take the position corresponding to that frame as the best positioning point for the label; Step S47: Use the obtained optimal positioning point as the standard position, and confirm or correct the original position of the reflective strip.

[0016] Preferably, in step S4, the second identifier is a barcode reader, which uses a high-speed imaging device to capture continuous images; the barcode reader is equipped with a high-precision encoder and an image recognition system, and the high-precision encoder obtains the precise position of each frame of image in real time when it is captured. The first identifier includes at least a reflective identifier. After detecting the reflective strip, it records the location of the reflective strip. At the same time, the exploration vehicle begins to decelerate. The reflective strip is set at a second fixed distance behind the travel tag. The specific operating steps are as follows: Step S41: The scout vehicle begins to decelerate from the location of the reflective strip until it moves at a low and constant speed, with a speed of less than 0.1 m / s. Step S42, the second identifier performs high-speed shooting until it completely passes through the storage location tag; Step S43: Use the image recognition system to determine which frame of the image has the clearest label and the most correct position, and take the position corresponding to that frame as the best positioning point for the label; Step S44: Use the obtained optimal positioning point as the standard position, and confirm or correct the original positions of the reflective strips and travel labels.

[0017] Preferably, before using the scout vehicle to perform code reading and ranging, the method further includes step S0, which involves using a second scout vehicle to quickly scan and read the entire OHT track and generate coarse position data; The second exploration vehicle includes at least: an RFID reader, a first identifier, and a high-speed camera. The first identifier includes a reflective identifier and a visual sensor, specifically: Step A: The second exploration vehicle system is initialized, and the exploration vehicle travels at a high speed and constant speed along the OHT track; Step B: The RFID reader reads the walking tag and records the location; Step C: The first reader detects the reflective strip or QR code and records its location; Step D: The high-speed camera takes continuous high-speed photos until it captures the storage location tag, and the location of the storage location tag is determined based on image processing and comparison. Step E: After the second exploration vehicle completes the entire track measurement, it uploads the data to the system, collecting all location information; Step F: Based on all location information, the system formulates a route plan for the exploration vehicle; After the exploration vehicle performs the system initialization step S1, it downloads the travel plan from the system and completes the subsequent steps S1-S6 according to the travel plan.

[0018] This invention employs a strategy of actively docking at the storage location before performing precise measurements. This fundamental change eliminates all ranging errors or cumulative errors caused by vehicle speed fluctuations, tire slippage, and sensor response delays. By fusing the encoder's cumulative distance and the relative distance from the onboard ranging sensor, dual verification and compensation are achieved, resulting in millimeter-level accuracy for the final "traveling tag-storage location" binding distance data. This means that when the OHT crane performs micro-movements based on this map data, it can accurately dock at the optimal code reading point in one go, greatly improving the reliability of subsequent operations.

[0019] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit this specification. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a flowchart illustrating the automatic pathfinding method of this application. Detailed Implementation

[0021] To better understand the above technical solutions, the technical solutions of the embodiments of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0022] like Figure 1 As shown, the present invention provides an automatic pathfinding method for an OHT track, comprising an OHT track and a pathfinding vehicle, wherein the pathfinding vehicle runs on the OHT track; The exploration vehicle is equipped with: an RFID card reader, a first identifier, and a second identifier; The OHT track is equipped with travel tags and storage location tags; The operation mode of the exploration vehicle includes the following steps: Step S1: System initialization. The scout vehicle travels along the OHT track. The scout vehicle can travel at high speeds, such as 2 m / s or higher, when no signal is detected.

[0023] Step S2: The RFID reader on the exploration vehicle reads the travel tag (RFID tag) and records the travel tag ID and current location information. Since RFID is a wireless reading method, it needs to be corrected according to the reading and writing distance of the RFID reader. For example, if the reading and writing distance is 5cm, the system records the travel tag (RFID tag) as the current RFID reader position + 5cm and corrects it accordingly. When entering the range of the travel tag, preferably, the exploration vehicle needs to slow down to avoid errors when reading and writing the storage tag later. Of course, if the exploration vehicle is traveling at a slow speed, it does not need to slow down. Step S3: The first identifier detects a potential storage location below the track; the exploration vehicle moves to the storage location tag and stops or moves at a low, constant speed. There are two modes for discovering potential storage locations. One is by reading the travel tag (RFID tag), which defaults to assuming a potential location is within the tag's range. The other is that the OHT track is equipped with reflective strips or other markers. The first reader is a reflective reader; after detecting the reflective strip, the first reader predicts a potential storage location behind it, and the scout vehicle begins to decelerate. The reflective strip can be set at a fixed distance in front of the storage tag. After the scout vehicle moves the first fixed distance, it stops or moves at a low, constant speed, activating the second reader.

[0024] Reflective strips can also be integrated with the storage location label, meaning the storage location label has built-in reflective strips. When the first reader detects the reflective strip, it confirms that there is a storage location label ahead, calculates the distance and speed, and then controls the deceleration and stops the vehicle.

[0025] In addition to reflective strips, other identification methods can be used, such as laser identification, infrared identification, shape identification, and electrical signal identification.

[0026] The stopping is for more accurate identification of storage location tags. Changing the existing technology's "instantaneous reading while moving," the exploration vehicle actively decelerates and precisely stops directly in front of a potential storage location after detecting it, stabilizing the reader in the optimal reading position. This eliminates ranging errors and reading ambiguity caused by vehicle movement, vibration, and speed, providing a stationary platform for high-precision ranging and reliable reading.

[0027] Step S4: In the docked state or in low-speed uniform motion, the second identifier is activated to read the storage location tag and obtain the storage location tag ID and type; Storage location labels can be one or more of the following: OHB labels, Port labels, and UTB labels. OHB labels are QR code labels, while Port and UTB labels are barcode labels. Other types of QR code or barcode labels are also acceptable.

[0028] Therefore, the second reader includes a barcode reader, and the label is a barcode label. The second reader reads the barcode label. Storage labels, such as Port labels or UTB labels, are barcode labels, and the second reader scans and identifies the Port label or UTB label.

[0029] The second reader may also include a QR code reader, where the label is a QR code tag, and the second reader reads the QR code tag. For example, a storage location tag could be an OHB tag, which is a QR code tag, and the second reader scans and identifies the OHB tag.

[0030] Both QR code labels and barcode labels can be used to store label ID, type, etc.

[0031] Different storage location tags are used on different OHT tracks; a single type of storage location tag or a hybrid type of storage location tag can be used. For example... Figure 1 The diagram shows a hybrid storage location label. In this embodiment, it includes Port or UTB labels, as well as OHB labels. Correspondingly, the exploration vehicle is equipped with a barcode reader and a QR code reader. In this embodiment, a reflective strip is provided in front of the Port or UTB label. The first reader of the exploration vehicle includes a reflective reader. After recognizing the reflective strip, the barcode reader reads the code. The first reader also includes a vision sensor (such as a wide-angle camera). When the presence of a QR code image is detected, the QR code reader reads the code.

[0032] The function of the first identifier is to predict or identify markers to confirm the storage location label behind it, and control the deceleration or stopping of the exploration vehicle based on the identified model. Therefore, based on this idea, various layout modes can be adopted. For example, reflective strips can be placed in front of both QR codes and barcodes, and the reflective identifier of the first identifier can identify the storage location label behind it by recognizing the reflective mirror. Alternatively, QR code and barcode storage location labels can be distinguished, with barcode labels identified by reflective strips and QR code labels identified by graphics, lasers, shapes, etc., which can also achieve the purpose of this invention.

[0033] This invention completely solves the problem of missed reads through a multi-stage strategy of "preliminary discovery - precise positioning - active reading" and an intelligent retry mechanism. It utilizes reflective detectors or visual sensors for large-area scanning to ensure that no potential storage locations are missed.

[0034] When stationary, the barcode reader has ample exposure and decoding time, is unaffected by vehicle speed, produces clear and stable images, and significantly improves the success rate of reading on the first attempt.

[0035] In active parking mode, when the first code reading fails, the system doesn't simply record the failure and continue. Instead, it initiates an intelligent retry mechanism. For example, it fine-tunes the vehicle's position, adjusts the reader's light intensity, and tries different exposure parameters to perform multiple reads until successful or the maximum number of retries is reached. This significantly reduces accidental missed reads caused by lighting conditions, dirt, or momentary interference, improving data integrity.

[0036] As a further preferred embodiment, two or more barcode readers are installed on the exploration vehicle, each pointing at a different angle (e.g., one tilted forward, one tilted backward) or with different depths of field. The vehicle travels at normal speed, and multiple barcode readers operate simultaneously.

[0037] The system backend collects the results from all barcode readers and uses a "voting mechanism" or selects the reading result with the "highest confidence" as valid data.

[0038] By combining encoder data, the location at the moment of successful code reading is taken as the positioning point. This can improve the code reading success rate without reducing vehicle speed.

[0039] Step S5: Calculate and record the distance from the nearest walking tag to the current storage tag, as well as the location information of the walking tag and the current storage tag.

[0040] Step S6: Associate and bind the travel tag ID, storage location tag ID, storage location type, location information (location information of travel tag, storage location tag and / or reflective strip, etc.), and distance information to generate binding relationship data.

[0041] Finally, the exploration vehicle continued to move, collecting information from different travel tags and storage location tags, forming complete data, and uploading it to the system.

[0042] In this embodiment, the travel tag is used for coarse positioning, and then the speed is reduced. After obtaining the reflective strip signal, the position of the reflective strip is used as the anchor point to further reduce the speed and accurately stop at the storage tag position for information reading and position confirmation.

[0043] The travel distance of the exploration vehicle is measured by instantaneous trigger readings during continuous travel. Its distance measurement core relies on pulse counting from motion sensors (such as encoders), and its physical basis is "number of wheel rotations × circumference". According to this invention, the distance between each stopping point can be determined, as well as the overall cumulative distance of the entire track.

[0044] This implementation changes the existing "instantaneous reading while in motion" mode. After detecting a potential storage location (e.g., through preliminary visual recognition or triggered by reflective strips), the exploration vehicle actively decelerates and precisely stops directly in front of the target storage location, stabilizing the barcode reader in the optimal reading position. This eliminates ranging errors and barcode ambiguity caused by vehicle movement, vibration, and speed, providing a stationary platform for high-precision ranging and reliable barcode reading.

[0045] This implementation method does not involve blind reading, but rather employs a "discovery-confirmation" process, which greatly improves the efficiency and targeting of pathfinding, avoids the blind operation of the code reader, and ensures that "no storage location is missed." At the same time, it fundamentally solves the problems of cumulative error and slippage error caused by relying solely on encoder distance calculation in traditional methods, resulting in extremely high accuracy of the bound distance values.

[0046] Meanwhile, this implementation method employs a strategy of actively docking at the storage location before performing precise measurements. This fundamental change eliminates all ranging errors or cumulative errors caused by vehicle speed fluctuations, tire slippage, and sensor response delays. By fusing the encoder's cumulative distance and the relative distance from the onboard ranging sensor, dual verification and compensation are achieved, resulting in millimeter-level accuracy for the final "traveling tag-storage location" binding distance data. This means that when the OHT crane performs micro-movements based on this map data, it can accurately dock at the optimal code reading point in one go, greatly improving the reliability of subsequent operations.

[0047] Furthermore, the dual ranging method proposed in this invention allows the system to automatically mark data as "suspicious data" when the difference between two distance values ​​exceeds a reasonable threshold, triggering an alarm or automatic re-detection. This built-in quality control function further ensures the quality controllability and reliability of the final map data output.

[0048] After successfully reading the data, the exploration vehicle automatically packages the {storage location tag ID}, {current travel tag ID}, {precise measurement distance}, and {storage location type} into a complete and reliable data record unit, and transmits or stores it in real time. The entire process requires no manual intervention and generates "plug-and-play" high-precision map files. It achieves full automation from data collection to output, completely eliminating reliance on manual post-processing.

[0049] The raw data output by this invention is inherently high-precision and highly complete. It can be directly imported into the OHT management system for use with little or no manual verification and data entry. This reduces the manual data processing work, which previously required several days and heavily relied on experience, to an automated process within minutes of the exploration vehicle's completion. It achieves full automation from data acquisition to map generation, significantly shortening the deployment, expansion, and maintenance cycle of the OHT system, and reducing labor costs and reliance on the experience of technical personnel.

[0050] This method provides accurate and complete data, preventing operational interruptions such as pick-and-place failures, mechanism collisions, and material jams caused by inaccurate positioning. The OHT crane can perform tasks smoothly and efficiently, improving the overall equipment efficiency (OEE) and reliability of the entire plant's material handling system.

[0051] This invention provides a second embodiment. In this embodiment, the parts that are the same as those in the above embodiments will not be repeated. The focus is on explaining the differences.

[0052] In step S4 above, the second identifier is a code reader. The code reader uses a high-speed shooting device (global shutter and high-frequency trigger) to capture continuous images. The code reader is equipped with a high-precision encoder and an image recognition system. The high-precision encoder obtains the precise position of each frame of the image in real time. The image recognition system determines which frame of the image has the clearest label and the most correct position, and takes the encoder position corresponding to that frame as the best positioning point of the label.

[0053] In step S3, after the first identifier discovers a potential storage space under the track, specifically, the first identifier includes at least a reflective identifier. After identifying the reflective strip, it records the location of the reflective strip. At the same time, the exploratory vehicle begins to decelerate.

[0054] The distance between the reflective strip and the storage location label is a first fixed distance. The exploration vehicle calculates its speed and stops based on this first fixed distance. Before reaching the location of the storage location label, the second sensor activates in advance to take high-speed photos. After reaching the predicted location of the storage location label, it stops and takes photos again. It then continues to move forward at a low speed for a certain distance, and the second sensor continues to take high-speed photos. Here, the sub-steps are explained in detail: Step S41: The scout vehicle begins to decelerate from the location of the reflective strip; Step S42: Based on the first fixed distance, predict the location of the storage location tag; Step S43: The scout vehicle takes a high-speed photo of the barcode reader 5-10cm before reaching the estimated location of the storage tag. Step S44: The exploration vehicle stops at the estimated location of the storage location tag and takes pictures; Step S45: The exploration vehicle moves forward slowly again by 5-10cm, while the barcode reader takes a high-speed photo. Step S46: Use the image recognition system to determine which frame of the image has the clearest label and the most correct position, and take the position corresponding to that frame as the best positioning point for the label; Step S47: Use the obtained optimal positioning point as the standard position, and confirm or correct the original position of the reflective strip.

[0055] In steps S43, S44, and S45 above, the precise position of each frame of image is obtained in real time through a high-precision encoder.

[0056] In this embodiment, the high-speed shooting and comparison function of the barcode reader can ensure that the exploration vehicle can travel at a relatively high speed without worrying about inaccurate or erroneous recognition of the reflective strip position. In other words, even if the exploration vehicle passes through the reflective strip position quickly and there is a recognition error, the precise position can be determined by subsequent image comparison with the barcode reader and then corrected in reverse.

[0057] This embodiment uses reflective strips as an example, but those skilled in the art should understand that other marking methods, such as laser marking, infrared marking, shape marking, etc., are also applicable, and the principle is the same in this invention.

[0058] This invention also provides a third embodiment. As can be seen from the above embodiments, the positions of the reflective strip and the storage tag can be accurately located. However, since the moving tag uses RFID wireless reading and writing, its location is coarse. Generally speaking, coarse location is sufficient for the moving tag as a region division criterion. However, in specific situations, there may be a need for precise location of the moving tag. Therefore, this embodiment is proposed.

[0059] In this embodiment, the OHT track is equipped with a reflective strip, which is positioned at a second fixed distance behind the travel label. After the first reader detects the reflective barcode, it corrects the position of the travel label, accurately locates it, and records the information. The positions of the reflective strip and the storage label are not fixed.

[0060] Specifically, in step S4 above, the second identifier is a code reader. The code reader uses a high-speed shooting device (global shutter and high-frequency trigger) to capture continuous images. The code reader is equipped with a high-precision encoder and an image recognition system. The high-precision encoder obtains the precise position of each frame of the image in real time. The image recognition system determines which frame of the image has the clearest label and the most correct position, and uses the encoder position corresponding to that frame as the best positioning point for the label.

[0061] In step S3, after the first identifier discovers a potential storage space under the track, specifically, the first identifier includes at least a reflective identifier. After identifying the reflective strip, it records the location of the reflective strip. At the same time, the exploratory vehicle begins to decelerate.

[0062] The distance between the reflective strip and the storage location tag is not fixed. The second detector takes high-speed photos, while the exploration vehicle moves at a low, constant speed (less than 0.1 m / s). The second detector continues to take high-speed photos until it completely passes the storage location tag. Here, each sub-step is described in detail: Step S41: The scout vehicle begins to decelerate from the location of the reflective strip; until the scout vehicle moves at a low and constant speed, with a speed less than 0.1 m / s. Step S42, the second identifier performs high-speed shooting until it completely passes through the storage location tag; Step S43: Use the image recognition system to determine which frame of the image has the clearest label and the most correct position, and take the position corresponding to that frame as the best positioning point for the label; Step S44: Use the obtained optimal positioning point as the standard position, and confirm or correct the original positions of the reflective strips and travel labels.

[0063] In this embodiment, the high-speed shooting and comparison function of the barcode reader is used to determine the detailed location of the storage location tag. The location of the reflective strip is then confirmed or corrected by the travel distance of the exploration vehicle. Furthermore, the precise location of the travel tag is derived by the second fixed distance and recorded. The travel tag, reflective strip, and storage location tag can all be accurately positioned.

[0064] The present invention also provides a fourth embodiment, in which there is no fixed positional relationship between the storage location label, reflective strip and travel label, and even no reflective strip is set (such as the storage location label is an OHB label), and precise positioning is achieved by a separate exploration vehicle.

[0065] In this embodiment, the second identifier is a barcode reader. The barcode reader uses a global shutter and high-frequency triggering to capture continuous images. The barcode reader is equipped with a high-precision encoder and an image recognition system. The high-precision encoder obtains the precise position of each frame of the image in real time. The image recognition system determines which frame of the image has the clearest label and the most correct position, and takes the encoder position corresponding to that frame as the optimal positioning point of the label. In step S4, the exploration vehicle moves at a low and uniform speed, less than 0.1 m / s. The second identifier continues to take high-speed pictures until it completely passes the storage tag, and then the image recognition system makes a judgment.

[0066] In this embodiment, the high-speed shooting and comparison function of the barcode reader can be used to determine the precise location of the storage tag.

[0067] This invention also provides a fifth embodiment. According to the aforementioned embodiments, the exploration vehicle needs to accelerate, decelerate, or maintain a constant speed depending on various conditions during its journey. This calculation relies on the exploration vehicle's own automatic control system. To ensure high reliability, the exploration vehicle sacrifices some speed to prevent untimely deceleration. However, this may reduce map drawing efficiency when the track to be measured is long or there are many potential storage locations.

[0068] In this embodiment, before using the scout vehicle to read and measure distances, step S0 is included, in which the second scout vehicle is used to quickly scan and read the entire track and generate coarse position data.

[0069] The second exploration vehicle includes at least: an RFID reader, a first identifier, and a high-speed camera. The first identifier includes a reflective identifier and a visual sensor, and its usage and principle are similar to those of the exploration vehicle, specifically: Step A: The second exploration vehicle system is initialized, and the exploration vehicle travels at a high speed and constant speed along the OHT track; Step B: The RFID reader reads the walking tag and records the location; Step C: The first reader detects the reflective strip or QR code and records its location; Step D: The high-speed camera takes continuous high-speed photos until it captures the storage location tag, and the location of the storage location tag is determined based on image processing and comparison. Step E: After the second exploration vehicle completes the entire track measurement, it uploads the data to the system and collects all locations (including running tags, reflective strips, storage tags, etc.). Step F: Based on all location information, the system formulates a route plan for the exploration vehicle; the route plan includes: the exploration vehicle's acceleration method, acceleration distance, acceleration time, deceleration method, deceleration distance, deceleration time, high-speed travel distance, travel time, speed, and stopping points, etc.

[0070] After the exploration vehicle performs the system initialization step S1, it downloads the travel plan from the system and completes the subsequent steps S1-S6 according to the travel plan.

[0071] If the data measured by the scout vehicle differs from the planned route during the execution of the plan, the scout vehicle will automatically revise the subsequent route plan based on the accurate data obtained.

[0072] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0073] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0074] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. The guide car is provided with: an RFID card reader, a first identifier, a second identifier; The OHT track is provided with a running tag and a storage location tag; characterized in that The guide car operation mode comprises the following steps: Step S1, system initialization, the guide car drives along the OHT track; Step S2, the RFID card reader on the guide car reads the running tag, records the running tag ID and the current position information; Step S3, the first identifier finds the potential storage location under the track; the guide car moves to the storage location tag position and stops or moves at a low speed; Step S4, in the stopped state or low-speed uniform motion, the second identifier is started to read the storage location tag, and the storage location tag ID and type are obtained; Step S5, the distance from the nearest running tag to the current storage location tag and the position information of the running tag and the current storage location tag are calculated and recorded; Step S6, the running tag ID, storage location tag ID, storage location type, position information and distance information are associated and bound to generate the binding relationship data.

2. The OHT track automatic routing method of claim 1, wherein, The OHT track is provided with a reflective strip, the first identifier includes a reflective identifier, the reflective strip is arranged at a first fixed distance in front of the storage tag, in step S3, after the first identifier detects the reflective strip, it is predicted that there is a potential storage location behind, the guide car starts to decelerate, moves the first fixed distance and stops, and then the second identifier is started.

3. The OHT track automatic routing method of claim 1, wherein, The OHT track is provided with a reflective strip, the first identifier includes a reflective identifier, the reflective strip is arranged at a second fixed distance behind the running tag, after the first identifier detects the reflective strip, the position of the running tag is corrected, accurately positioned and recorded.

4. The OHT track automatic routing method of claim 2, wherein, The second identifier includes a barcode reader, the storage location tag includes a Port tag or a UTB tag, the Port tag or the UTB tag is a barcode tag, and the second identifier scans and identifies the Port tag or the UTB tag.

5. The OHT track automatic routing method according to claim 1 or 2, wherein, The second identifier includes a two-dimensional code reader, the storage location tag includes an OHB tag, the OHB tag is a two-dimensional code tag, and the second identifier scans and identifies the OHB tag.

6. The OHT track automatic routing method of claim 5, wherein, The first identifier also includes a visual sensor, when the two-dimensional code pattern is identified, the two-dimensional code reader reads the code.

7. The OHT track automatic routing method of claim 1, wherein, The second identifier is a code reader, the code reader adopts a global shutter and a high-frequency trigger to capture continuous images; the code reader is provided with a high-precision encoder and an image recognition system, the accurate position of each frame of image shooting is obtained in real time through the high-precision encoder; through the image recognition system, it is judged which frame of image has the clearest tag and the most correct position, and the encoder position corresponding to the frame is taken as the best positioning point of the tag; In step S4, the guide car moves at a low speed, and the moving speed is less than 0.1 m / s.

8. The OHT track automatic routing method of claim 1, wherein, In step S4, the second identifier is a code reader, the code reader adopts a high-speed shooting device to capture continuous images; the code reader is provided with a high-precision encoder and an image recognition system, the accurate position of each frame of image shooting is obtained in real time through the high-precision encoder; The first identifier at least includes a reflective identifier, after the reflective strip is identified, the position of the reflective strip is recorded, and at the same time, the guide car starts to decelerate; the distance between the reflective strip and the storage location tag is a first fixed distance; The specific operation steps are as follows: Step S41, the pathfinder starts to decelerate from the position of the reflective strip; Step S42, the position of the storage location label is predicted according to the first fixed distance; Step S43, the pathfinder reaches the position 5-10 cm in front of the estimated position of the storage location label, and the code reader performs high-speed shooting; Step S44, the pathfinder stops at the estimated position of the storage location label and takes a picture; Step S45, the pathfinder moves forward at a low speed of 5-10 cm again, and the code reader performs high-speed shooting at the same time; Step S46, the image recognition system determines which frame of image has the clearest label and the most correct position, and takes the position corresponding to the frame as the best positioning point of the label; Step S47, the obtained best positioning point is taken as the standard position, and the original position of the reflective strip is confirmed or corrected.

9. The OHT track automatic routing method of claim 1, wherein, In the step S4, the second identifier is a code reader, which uses a high-speed shooting device to capture continuous images; a high-precision encoder and an image recognition system are arranged on the code reader, and the accurate position of each frame of image during shooting is obtained in real time through the high-precision encoder; The first identifier at least includes a reflective identifier, which records the position of the reflective strip after identifying the reflective strip, and the pathfinder starts to decelerate at the same time; the reflective strip is arranged at a second fixed distance behind the walking label; The specific operation steps are as follows: Step S41, the pathfinder starts to decelerate from the position of the reflective strip; until the pathfinder moves at a low uniform speed, and the moving speed is less than 0.1 m / s; Step S42, the second identifier performs high-speed shooting until the storage location label is completely passed; Step S43, the image recognition system determines which frame of image has the clearest label and the most correct position, and takes the position corresponding to the frame as the best positioning point of the label; Step S44, the obtained best positioning point is taken as the standard position, and the original position of the reflective strip and the walking label is confirmed or corrected.

10. The OHT track automatic routing method of claim 1, wherein, Before using the pathfinder to read the code and measure the distance, step S0 of using a second pathfinder to quickly scan and read / write the entire OHT track and generating rough position data is further included; The second pathfinder at least includes: An RFID card reader, a first identifier, and a high-speed camera, wherein the first identifier includes a reflective identifier and a visual sensor, specifically: Step A: the second pathfinder system is initialized, and the pathfinder moves at a high uniform speed along the OHT track; Step B: the RFID card reader reads the walking label and records the position; Step C: the first identifier identifies the reflective strip or the two-dimensional code and records the position; Step D: the high-speed camera continuously takes high-speed photos until the storage location label is taken, and the position of the storage location label is determined according to image processing and comparison; Step E: after the second pathfinder completes the measurement of the entire track, the data is uploaded to the system, and all position information is collected; Step F: the system formulates a travel plan of the pathfinder according to all the position information; After the pathfinder executes the above step S1 system initialization step, the travel plan is downloaded from the system, and the subsequent steps S1-S6 are completed according to the travel plan.

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