Safety control method of walking system of unattended stacker-reclaimer in bar stockyard

Abstract

The application discloses a safety control method of a walking system of an unattended stacker-reclaimer in a strip stockyard, and belongs to the field of industrial automation; the method comprises a multi-source fusion positioning system, a communication system and an artificial intelligence control system which are composed of a Gray bus, an RFID card reader and an absolute value encoder; after the system acquires the real-time position of a track of the stacker-reclaimer, multi-stage safety control is executed: when walking to the end of the track and a cable turnover device, the speed is reduced in stages; the same-track double stacker-reclaimers intelligently prevent collision according to the running direction; when the stacker-reclaimer cross-works, the speed reduction and interlocking are triggered in turn according to the distance in descending order, and the reclaimer crossing must be carried out after the stacker-reclaimer belt is stopped; the application also integrates dynamic interlocking and communication redundancy, realizes multi-level redundancy protection in all working conditions, and significantly improves the safety and reliability of the walking system.

Description

Technical Field

[0001] This invention relates to the field of industrial automation, and in particular to a safety control method for the walking system of an unattended stacker-reclaimer in a strip yard. Background Technology

[0002] Stacker cranes are high-efficiency equipment for the continuous conveying and unloading of dry bulk materials in bar-shaped material yards, while reclaimers are high-efficiency equipment for the continuous conveying and retrieving of dry bulk materials in bar-shaped material yards. They are generally used in pairs and are widely applied in material storage and retrieval operations at bar-shaped material storage sites such as coking plants, power plants, steel plants, metallurgy, cement plants, ports, and docks. With the continuous improvement of industrial automation, the storage scale of bar-shaped material yards is increasing, the number of equipment is constantly increasing, and the complexity of the systems is significantly increasing. Unmanned operation of material yards has become an inevitable trend in the industry. In unmanned systems, stacker cranes need to automatically complete a series of actions such as walking, stacking, and retrieving according to a preset path. The walking system is the foundation for stacker cranes to perform all operational tasks. Stacker cranes typically travel back and forth on tracks hundreds of meters long, with the ends of the track forming the boundaries of the material yard. Multiple stacker cranes may operate simultaneously on the same track, with both parallel and overlapping operations between the equipment. Key facilities such as cable reel turning devices also exist around the track, making the operating conditions extremely complex. If the walking system experiences positioning deviations, speed loss, or collisions, it can not only cause severe equipment damage but also lead to prolonged production shutdowns, resulting in significant economic losses and safety hazards. Therefore, improving the reliability and safety of the walking system of stacker-reclaimers is the primary challenge and core issue that unmanned stockyard systems must address. Currently, existing technologies for the safety control of stacker-reclaimer walking systems have the following shortcomings: Existing solutions mostly employ a single sensor for position detection, such as relying solely on a Gray busbar or an encoder for positioning. While the Gray busbar can provide absolute position information, its data refresh rate is low, failing to reflect instantaneous position changes in a timely manner when the stacker-reclaimer is moving at high speeds. Encoders, although having a high data update frequency, suffer from accumulated errors due to wheel slippage and mechanical wear over long-term operation, and lack self-correction capabilities. Single-sensor solutions struggle to simultaneously achieve global accuracy, real-time performance, and long-term stability in positioning. Existing solutions typically only install simple limit switches at both ends of the track, triggering a stop only when the stacker-reclaimer reaches the end of the track. This lack of a pre-emptive, graded deceleration mechanism results in high impact force and long braking distances when the equipment rushes towards the end at high speed, causing severe damage to the equipment and track foundation. For multi-machine operations on the same track, existing technologies often use fixed safety distance thresholds for simple start-stop control, lacking intelligent judgment based on the direction of travel, which can easily lead to unnecessary shutdowns or fail to effectively prevent collisions. Existing systems often rely on a single type of sensor for environmental perception, lacking redundancy and backup when sensors fail, resulting in insufficient reliability. Furthermore, the stacker-reclaimer's traveling system lacks robust dynamic interlocking logic with its stacker-reclaimer and pitching mechanisms. When one mechanism malfunctions, the others continue operating, potentially leading to secondary accidents. Existing systems mostly use a single communication link. Once the communication is interrupted, the entire unattended system will be paralyzed, and the central control room will be unable to monitor or intervene in the field equipment, resulting in extremely high security risks. In summary, the existing technology lacks a safety control method for stacker-reclaimer walking systems that can integrate multi-source positioning data, have multi-level graded deceleration protection, and multiple redundant safety protections, and cannot meet the requirements of unmanned systems in large strip material yards for walking safety and reliability. Summary of the Invention

[0003] The main objective of this invention is to provide a safety control method for the walking system of an unattended stacker-reclaimer in a strip yard, aiming to solve existing technical problems.

[0004] To achieve the above objectives, the present invention provides a safety control method for the walking system of an unattended stacker-reclaimer in a strip material yard, comprising: The real-time positioning monitoring system, including the Gray busbar, trolley positioning RFID reader and absolute encoder, is used to measure the position and travel speed of the stacker-reclaimer in the material yard. The communication system, connected to the artificial intelligence control system and stacker-reclaimer equipment, is used to enable data interaction between the system and the stacker-reclaimer equipment and related electrical components in the bar stockyard. The artificial intelligence control system has a built-in multi-machine collaborative control unit, path planning unit and intelligent decision-making unit, which is used to receive and integrate multi-source sensing data, generate work task allocation schemes, work path planning and material stacking and picking strategies, and issue operation instructions. Based on the real-time positioning monitoring system, the actual distance between the stacker-reclaimer and the designated position on the track is obtained, and the following safety control logic is executed based on this actual distance: When the stacker-reclaimer moves toward the end of the track and the actual distance is not greater than the first distance threshold, the frequency converter of the walking system drops to the first frequency; when the actual distance is not greater than the second distance threshold, the frequency converter further drops to the second frequency until it stops at a predetermined position, where the second distance threshold is less than the first distance threshold and the second frequency is less than the first frequency. When the stacker-reclaimer moves to within the first distance threshold of the cable reel overturning device, the frequency converter drops to the first frequency; Collision avoidance control between two stackers on the same track: real-time acquisition of the precise position of the two stackers, calculation of the distance between the two vehicles, and when the distance is less than the first distance threshold, determination of whether to trigger safety protection based on the direction of the vehicle's movement; Collision avoidance control between the high-level stacker and the low-level reclaimer: The precise positions of the stacker and the reclaimer are acquired in real time, and the horizontal clearance is calculated. When the clearance is less than the third distance threshold, the operating frequency is smoothly reduced to the first frequency. When the clearance is less than the fourth distance threshold, a safety interlock is triggered. The fourth distance threshold is less than the third distance threshold.

[0005] Furthermore, in the real-time positioning monitoring system, the Gray busbar, the trolley positioning RFID reader, and the absolute encoder constitute a multi-source fusion positioning architecture. The positioning result of the Gray busbar is used as the main reference to output the full track position. The high-frequency pulse data of the absolute encoder is used to fill the positioning refresh rate. The positioning result is periodically corrected by RFID landmarks deployed along the track to eliminate wheel slippage or encoder cumulative error.

[0006] Furthermore, the multi-source fusion positioning architecture employs a data fusion algorithm to perform synchronous registration, outlier removal, and dynamic weighted fusion of the three types of sensor signals. It also dynamically allocates fusion weights based on the real-time signal quality of each sensor and incorporates automatic redundancy switching logic in case of single-channel sensor failure.

[0007] Furthermore, the artificial intelligence control system also includes; The data acquisition and preprocessing module is used to collect material pile information and motor current data and perform preprocessing. The data processing module is used to smooth the point cloud and extract features from the preprocessed material pile information, and to render the material pile shape in 3D, as well as to filter the motor current data to obtain the motor temperature data. The model training module is used to train the equipment fault diagnosis model; The logic control module is used to generate stacking and reclaiming path planning instructions and walking status safety control instructions based on the processed data.

[0008] Furthermore, it also includes a multi-source environmental perception subsystem composed of obstacle avoidance radar, material level radar, and inclinometer; the obstacle avoidance radar is installed around the stacker-reclaimer body to detect the distance between the stacker-reclaimer and the end of the track, adjacent equipment, and surrounding obstacles; the material level radar is installed on the reclaimer to monitor the height of the material pile; the inclinometer is installed on the reclaimer's rake plate to monitor the rake plate's pitch angle.

[0009] Furthermore, the communication system includes a wired communication link and a wireless communication link. Under normal operating conditions, the wired communication link is the main link and the wireless communication link is the hot standby link. When the main link is interrupted, it automatically switches to the standby link to achieve redundant backup communication with the artificial intelligence control system.

[0010] Furthermore, it also includes dynamic interlock logic: establishing an interlock relationship between the walking system and the stacking and reclaiming mechanism and the pitching mechanism. When the stacking and reclaiming mechanism or the pitching mechanism is in an abnormal state, or when the obstacle avoidance radar and the machine vision unit determine that there are people or obstacles around the track, the operation of the corresponding mechanism is automatically locked, and the interlock is automatically released after the abnormality is eliminated.

[0011] Furthermore, a travel limit switch and an extreme limit switch are installed on the stacker-reclaimer body, and corresponding triggering blocks are installed at the predetermined stopping position on the track and at the end of the track. The travel limit switch and the extreme limit switch, together with the graded deceleration control of the frequency converter and the software stop command of the artificial intelligence control system, form multiple redundant protections.

[0012] Furthermore, in the anti-collision control between two stackers on the same track, when the distance between the two vehicles is less than the first distance threshold, if the direction of travel of the main vehicle will cause the distance between the two vehicles to decrease further, then safety protection will be triggered and relative travel will be prohibited; if the direction of travel increases the distance between the two vehicles, then the equipment is allowed to operate normally.

[0013] Furthermore, in the anti-collision control between the high-level stacker and the low-level reclaimer, the system determines the current stacking operation area based on the running status of the stacker belt and predicts the reclaimers that may pass through the area; when the reclaimer crosses the stacking operation area, it can only be executed after the stacker belt has stopped running; the first distance threshold is greater than the third distance threshold, the third distance threshold is greater than the fourth distance threshold, and the first frequency is higher than the second frequency.

[0014] The beneficial effects of this invention are reflected in: This invention employs a multi-source fusion positioning architecture comprised of a Gray bus, a trolley positioning RFID reader, and an absolute encoder. The Gray bus provides global continuous absolute coordinates as the primary reference, while the absolute encoder uses high-frequency pulses for dynamic interpolation to significantly improve the positioning refresh rate. RFID markers deployed along the track enable periodic error clearing. These three components complement each other, ensuring global positioning accuracy and achieving millisecond-level high-frequency dynamic response, while eliminating the cumulative errors caused by wheel slippage during long-term operation. Compared to single-sensor positioning schemes, this invention significantly improves positioning accuracy, and the system can continue to output reliable positioning data even when any single sensor fails, providing a solid data foundation for all subsequent safety control logic. Furthermore, this invention uses a Kalman filter algorithm for synchronous registration, outlier filtering, and dynamic weighted fusion of the three types of sensor signals, further enhancing the stability and anti-interference capability of the positioning data in harsh environments such as dust and water mist.

[0015] This invention addresses the scenario of a stacker-reclaimer moving towards the end of a track. It abandons the traditional approach of simply triggering a stop with a limit switch at the end, instead automatically reducing the travel frequency to 5Hz 15m from the track end, allowing the stacker-reclaimer to enter a safe low-speed state in advance. At 3m from the end, it further reduces the frequency to 2Hz, crawling at ultra-low speed until precisely stopping at the predetermined position. This two-stage deceleration mechanism effectively shortens the emergency braking distance and significantly reduces the possibility of damage to the equipment and track from high-speed impacts, making it particularly suitable for stacker-reclaimers weighing hundreds of tons in large stockyards. Simultaneously, the staged deceleration, along with the onboard travel limit switches, travel extreme limit switches, and the AI ​​control system software's stop command, constitutes triple redundancy protection, ensuring reliable and safe stopping even in extreme situations such as data anomalies, program crashes, and inverter failures. This level of safety far surpasses existing single-protection solutions.

[0016] This invention addresses collision avoidance control between two stackers on the same track by designing a protection logic based on intelligent judgment of their running direction. Unlike traditional solutions that simply trigger a stop based on distance, this invention further determines the running direction of the stackers when the distance between the two machines is less than a safety threshold: if the direction causes the distance between the two machines to decrease further, protection is triggered and relative movement is prohibited; if the direction increases the distance between the two machines, normal operation is allowed. This logic effectively avoids unnecessary downtime and significantly improves the system's operational efficiency. Simultaneously, for complex scenarios where a high-level stacker crosses a low-level reclaimer, this invention designs an intelligent stacking area determination mechanism based on the stacker belt's running status and sets a two-level response strategy based on the distance between the two machines: a 10m deceleration and a 5m stopping interlock. Specifically, it stipulates that the reclaimer can only perform the crossing operation after the stacker belt has completely stopped, fundamentally eliminating the collision risk when high-level stacking and low-level reclaiming machines operate in the same area, demonstrating a rigorous and comprehensive safety logic.

[0017] This invention employs multiple obstacle avoidance radars, installed at the tail of the stacker crane, the gantry, and both sides of the fixed end, swing end, and rake plate of the reclaimer, forming an omnidirectional, blind-spot-free detection field. This allows simultaneous monitoring of the distance between the stacker / reclaimer and the track end anti-collision posts, adjacent equipment, and surrounding personnel. The obstacle avoidance radars and machine vision unit form a dual-redundancy detection mechanism. When a single sensor detects an obstacle, the system enters a warning and deceleration state; when both sensors simultaneously confirm an obstacle, an emergency stop is executed. This avoids frequent shutdowns caused by false alarms from a single sensor and ensures reliable safety response. Furthermore, this invention establishes dynamic interlocking logic between the walking system and the stacker / reclaim and pitching mechanisms. When any mechanism malfunctions or detects an obstacle, the corresponding mechanism is automatically locked, effectively preventing the escalation of accidents and embodying a system-level safety design concept.

[0018] The communication system employed in this invention combines wireless and wired communication capabilities. Under normal operating conditions, the wired link is the primary link, with the wireless link serving as a hot backup. When the primary link fails, the system automatically and seamlessly switches to the backup link within milliseconds, ensuring uninterrupted data interaction between the AI ​​control system and field equipment. This design enables control room operators to maintain monitoring and intervention capabilities for field equipment under any circumstances, fundamentally eliminating the significant safety hazard of system loss of control due to communication interruptions. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the safety control method for the walking system of the unmanned stacker-reclaimer in the strip material yard according to the present invention; Figure 2 Electrical component diagram of the real-time positioning monitoring system of the present invention; Figure 3 A schematic diagram of the system architecture of this invention; Figure 4 A schematic diagram of the control logic architecture of this invention; Figure 5 A schematic diagram of the multi-level security protection logic of this invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1-5The present invention provides a safety control method for the walking system of a stacker-reclaimer in an unmanned bulk material storage system in a closed strip storage yard. The system architecture mainly consists of three parts: a real-time positioning monitoring system, a communication system, and an artificial intelligence control system. The artificial intelligence control system is the core of the entire unmanned system, incorporating a multi-machine collaborative control unit, a path planning unit, and an intelligent decision-making unit. It is connected to the real-time positioning monitoring system, the communication system, and the DCS control systems of each stacker-reclaimer via an industrial Ethernet network. The artificial intelligence control system also includes a data acquisition and preprocessing module, a data processing module, a model training module, and a logic control module. The data acquisition and preprocessing module collects real-time 3D point cloud data of the material pile surface using a laser 3D stacking scanner installed on the stacker-reclaimer, and collects real-time current data of each drive motor using Hall sensors. The data processing module smooths and extracts features from the material pile point cloud data using a Gaussian algorithm with a five-point kernel weighting algorithm, and uses Tree.js front-end technology for 3D rendering to obtain a 3D stacking model of the material pile. The model training module trains a fault diagnosis model based on historically collected temperature and vibration sensor data. The logic control module generates stacking-reclaiming path planning instructions and walking status safety control instructions based on the processed material pile shape data, equipment location data, and fault diagnosis results. The entire system adopts a redundant architecture design, with two AI control servers in the central control room serving as hot backups. When the primary server fails, the backup server automatically takes over all control tasks within seconds, ensuring uninterrupted 24 / 7 operation of the system.

[0022] Installation of the Gray busbar: The Gray busbar is laid continuously along the support legs of the conveyor belt connected to the stacker-reclaimer's inlet and outlet, serving as the primary positioning source for global continuous absolute coordinates. The Gray busbar consists of a nylon fiber-reinforced synthetic outer shell and internal core wires braided according to binary digital encoding rules, and is installed on the support legs of the conveyor belt connected to the stacker-reclaimer's inlet and outlet. The Gray busbar position detection device detects displacement by measuring the relative position between the closely spaced flat Gray busbar and the antenna box. It is a non-contact position detection sensor with a positioning accuracy of up to 5mm. The specific installation steps are as follows: First, install a dedicated bracket every 1.5m to 2m along the associated conveyor belt support legs. The bracket height should ensure that the gap between the upper surface of the Gray busbar and the lower surface of the antenna box remains within 50mm ± 10mm. Second, lay the Gray busbar cable segment by segment on the bracket and secure it using dedicated clamps. The nuts on the fixed bracket end need to be tightened first, while the nuts on the clamp end can be tightened temporarily. After the entire Gray busbar is installed, pull the Gray busbar simultaneously from both ends to keep it straight and with a certain preload. Then tighten the nuts on the clamp end one by one. The third step is to complete the waterproof sealing treatment of the Gray busbar joints. All joints should be sealed with a dedicated waterproof junction box to ensure insulation performance and signal transmission quality in the high dust and high humidity environment of the material yard. The fourth step is to adjust the relative position between the antenna box and the Gray busbar after the antenna box is installed below the stacker-reclaimer body, ensuring that the center line of the antenna box is aligned with the center line of the Gray busbar, with a deviation not exceeding 5mm.

[0023] Installation of RFID readers and markers for trolley positioning: The RFID readers for trolley positioning are installed on the support legs of the conveyor belts connected to the stacker-reclaimer's inlet and outlet. Each stacker-reclaimer is equipped with one reader. RFID markers are deployed in sections along the track, with one marker installed on the track sleepers or dedicated supports every 50m to 100m. Each marker is pre-written with the standard track coordinates for that point. The markers use industrial-grade UHF RFID tags, which are dustproof, waterproof, and high-temperature resistant, suitable for harsh material yard environments. When the stacker-reclaimer passes each RFID marker, the RFID reader automatically reads the pre-calibrated standard coordinates. The system uses these standard coordinates to correct the current positioning value, eliminating positioning deviations caused by wheel slippage, wear, or cumulative encoder errors in one step.

[0024] Installation of the absolute encoder: The absolute encoder is installed on the axle of the stacker-reclaimer's traveling wheel and connected to the axle via a flexible coupling. A multi-turn absolute encoder is selected, with a single-turn resolution of at least 13 bits and a multi-turn counting range of at least 12 bits, capable of recording the total number of rotations and angles of the traveling wheel. The encoder is connected to the high-speed counting module of the stacker-reclaimer's DCS control system via a shielded cable. It generates high-frequency pulse signals as the traveling wheel rotates, used to fill the dynamic interpolation between two positioning outputs of the Gray busbar, improving the positioning refresh rate to the millisecond level. During installation, attention must be paid to the coaxiality of the encoder shaft and the traveling wheel axle; the deviation should not exceed 0.1mm. A flexible coupling is used to absorb vibration and impact during operation.

[0025] Inclinometer Installation: The inclinometer is installed at the base of the rake plate of the reclaimer, near the hinge point, to monitor the pitch angle of the rake plate relative to the horizontal plane in real time. The inclinometer uses a dual-axis high-precision MEMS inclinometer with a measurement range of ±45°, a monitoring accuracy of no less than 0.1°, and a protection rating of no less than IP67. During installation, ensure that the mounting surface of the inclinometer is parallel to the longitudinal axis of the rake plate. The mounting base is bolted to the rake plate structure, and vibration damping pads are installed at the installation location to isolate vibrations during equipment operation.

[0026] Installation of Obstacle Avoidance Radars: Multiple obstacle avoidance radars are installed on both sides of the stacker crane's tail section, the front and rear ends of the stacker crane's gantry, both sides of the reclaimer's fixed end, both sides of the reclaimer's swing end, and both sides of the reclaimer's rake plate. Each obstacle avoidance radar has a detection range of no less than 20 meters and millimeter-level ranging accuracy. The detection areas of multiple obstacle avoidance radars overlap and overlap, forming an omnidirectional detection field around the stacker crane with no blind spots. During installation, care must be taken to ensure that the detection sector of each radar is not obstructed by the equipment's own structure, the radar mounting brackets are secure and reliable, and on-site calibration is performed after installation to confirm that the detection range of each radar covers the entire hazardous area.

[0027] Installation of the level radar: The level radar is installed in the center of the reclaimer's rake plate. It is used to emit radar waves onto the surface of the material pile and receive the echoes to monitor the height and level distribution of the material pile in real time. The level radar is a frequency-modulated continuous wave (FMCW) radar with a measurement range of 0.5m to 30m and a measurement accuracy of ±10mm. During installation, ensure that the radar wave emission direction is perpendicular to the expected landing area on the material pile surface, and the mounting bracket should have anti-vibration and anti-loosening functions.

[0028] The communication system includes an industrial Ethernet backbone network located in the central control room, a fiber optic ring network laid along the track, wireless communication terminals installed on the stacker-reclaimer itself, and wired communication interfaces. The ring network fiber optic cables and power cables are laid along the same route using a three-in-one special cable. The fiber optic cables connect the central control room switch to the industrial switches in the control boxes of each stacker-reclaimer, forming the wired communication backbone link. The fiber optic ring network adopts a ring topology; if any fiber optic cable breaks at any point in the ring network, the ring network switch automatically reconfigures the link within 50ms, ensuring uninterrupted communication. The wireless communication terminal uses a 5.8GHz industrial-grade wireless bridge, installed on the top of the stacker-reclaimer, establishing a wireless communication link with the wireless access point in the central control room, forming a wireless communication backup link. The wireless bridge uses a directional antenna with a gain of no less than 15dBi, ensuring a signal strength of no less than 65dBm within a 500m range. Under normal operating conditions, the wired communication link serves as the main link for transmitting all control commands and sensor data, while the wireless communication link is in hot standby mode for real-time data synchronization. When the wired communication link is interrupted, the system automatically and seamlessly switches to the wireless communication link within milliseconds to continue transmitting data, ensuring that the data interaction between the artificial intelligence control system and field equipment is never interrupted.

[0029] Three-source collaborative positioning: The system uses the Gray line positioning result as the primary reference to complete the full-track positioning output. The Gray line outputs the absolute position coordinates of the stacker-reclaimer along the entire track in real time through electromagnetic induction, with a data refresh rate of 10Hz. The absolute encoder collects the rotation pulses of the traveling wheels in real time at a sampling frequency of no less than 1kHz, which is used to fill the dynamic interpolation between two Gray line positioning outputs. RFID landmark data serves as a verification reference, and periodic error zeroing is completed when the stacker-reclaimer passes through each RFID landmark point. The three work together to form a three-source collaborative positioning architecture, using the Gray line positioning result as the primary reference to complete the full-track positioning output, the encoder pulse data as an auxiliary reference to complete dynamic interpolation to improve the positioning refresh rate, and the RFID landmark data as a verification reference to complete the periodic error zeroing.

[0030] Kalman Filter Data Fusion: The Kalman filter algorithm is used to process three types of sensor data. The specific processing flow is as follows: First, the three types of sensor signals are pre-processed and filtered to remove signal fluctuations caused by environmental noise such as dust and water mist. The Gray bus signal uses median filtering to remove sudden interference, the encoder signal uses low-pass filtering to eliminate high-frequency noise, and the RFID signal uses confidence level judgment to remove abnormal readings. Second, unified timestamp registration is performed based on the time tags of each sensor data. Since the data sampling times of the three types of sensors are different, the system uses linear interpolation to unify all data to the same time base. Third, outliers exceeding the reasonable range of variation are identified and filtered out. For example, when the pulse increment of the encoder in a unit time exceeds the theoretical number of pulses corresponding to the maximum walking speed, it is judged as an outlier and removed. Finally, the fusion calculation weights are dynamically allocated based on the real-time signal-to-noise ratio of each sensor. Sensors with high signal-to-noise ratios are given higher fusion weights, and sensors with low signal-to-noise ratios are automatically given lower weights. The fusion positioning result is output every 100ms, and the positioning accuracy can be controlled within 5cm.

[0031] Single-channel sensor failure redundancy switching: The system has built-in automatic switching redundancy logic for single-channel sensor failure. When the Gray bus signal is lost, it automatically switches to a backup positioning mode that uses an absolute encoder as the primary sensor and RFID landmarks for periodic calibration; when the absolute encoder fails, it automatically switches to a positioning mode that uses the Gray bus as the primary sensor and RFID landmarks for verification; when the RFID reader fails, it automatically switches to a dual-source fusion positioning mode using the Gray bus and encoder. Even with the failure of any single sensor, the system can still continuously output reliable positioning data, with a positioning accuracy no less than 1.5 times that of a single sensor operating normally.

[0032] When the AI ​​control system plans a path requiring the stacker-reclaimer to move towards the end of the track, the system calculates the real distance D_real between the current position of the stacker-reclaimer and the predetermined stopping position at the end of the track in real time based on the fusion positioning results, and continuously monitors this distance at a refresh rate of no less than 10Hz.

[0033] Phase 1 (D_real ≤ 15m): When D_real decreases to 15m, the AI ​​control system immediately sends a deceleration command to the travel system's frequency converter. The frequency converter reduces its operating frequency (usually 50Hz) to 5Hz within 1 second. At this time, the stacker-reclaimer's travel speed decreases from its normal operating speed (approximately 30m / min) to a safe low speed (approximately 3m / min), ensuring that the stacker-reclaimer approaches the track end at a safe low speed. This deceleration process is forced and is not affected by the stacker-reclaimer's current operating status. Even if the stacker-reclaimer is performing stacking or reclaiming operations, the travel system still executes the forced deceleration command.

[0034] Phase Two (D_real ≤ 3m): When D_real further decreases to 3m, the inverter frequency drops from 5Hz to 2Hz, and the stacker-reclaimer crawls at an ultra-low speed (approximately 1.2m / min). At this time, the artificial intelligence control system continuously monitors the rate of change of D_real. When the rate of change approaches zero, it determines that the stacker-reclaimer has reached the predetermined stopping position, issues a precise stopping command, and the inverter performs zero-speed braking and brake engagement to complete the stopping.

[0035] The third layer of redundant protection: Travel limit switches are installed at the front and rear end beams of the stacker-reclaimer body, and travel limit switches are installed at the extreme ends of the end beams. Both travel limit switches and travel limit switches are mechanical contact switches with a protection rating of at least IP67. At predetermined stopping positions at both ends of the track, a first impact block is fixedly installed to trigger the travel limit switches, and a second impact block is fixedly installed on the outer side of the first impact block, closer to the end of the track, to trigger the travel limit switches. Both the first and second impact blocks are wedge-shaped metal blocks with a gradually tapering contact slope along the track direction.

[0036] When the stacker-reclaimer reaches the predetermined stopping position, the first impact block presses the travel limit switch, which then sends a deceleration and stop signal. If the travel limit switch fails or the stacker-reclaimer overshoots the predetermined stopping position due to inertia, the second impact block presses the travel extreme limit switch, which directly cuts off the power supply to the main circuit of the travel system, achieving forced power-off stopping. The deceleration and stop signal from the travel limit switch is independent of the inverter's graded deceleration control signal and, together with the software logic stop command of the artificial intelligence control system, forms triple redundancy protection.

[0037] The stacker-reclaimer is equipped with a cable reel turning device, which is used to reel in and unreel power and control cables during the stacker-reclaimer's movement. When the stacker-reclaimer reaches or is within 15m of its respective cable reel turning device, the artificial intelligence control system detects that D_real ≤ 15m based on the fusion positioning result and immediately issues a deceleration command to the travel system frequency converter.

[0038] Within one second, the frequency converter drops from the current operating frequency to 5Hz, allowing the stacker-reclaimer to pass through the section containing the cable reel tipping device at a safe low speed (approximately 3m / min). Throughout this low-speed passage, the system continuously monitors the relative position of the stacker-reclaimer and the cable reel tipping device. Only when the stacker-reclaimer has completely passed the device and the distance has returned to greater than 15m plus 2m hysteresis is the frequency converter allowed to return to normal frequency for continued operation.

[0039] This deceleration control ensures that the winding and unwinding speed of the special cable is synchronized with the walking speed of the stacker-reclaimer during the vehicle's movement, effectively preventing accidents such as excessive cable stretching, reel jamming, or cable damage caused by excessive walking speed.

[0040] When two stacker cranes are operating simultaneously on the same track, the AI ​​control system uses a real-time positioning monitoring system to obtain the precise positions of the two stacker cranes in real time at a refresh rate of no less than 10Hz, denoted as A and B respectively. The system caches the position history data of the most recent 5 seconds using a rolling time window and continuously calculates the distance between the two cranes, Length = |AB|. When Length ≥ 15m, the two stacker cranes travel normally according to their planned paths without interfering with each other. When Length < 15m, the system triggers the anti-collision protection program, specifically executing the following judgment logic: The first step is for the system to read the current operating frequency and direction commands of the two stacker trolley frequency converters and determine their current operating direction.

[0041] The second step involves the system determining a dangerous proximity situation if the two stacker cranes are traveling in opposite directions (i.e., stacker crane A is moving towards stacker crane B while stacker crane B is simultaneously moving towards stacker crane A). The system immediately triggers safety protection, sending stop commands to the frequency converters of both stacker cranes' travel systems simultaneously. A message stating "Safe distance reached, movement prohibited" appears on the human-machine interface in the central control room. Simultaneously, the system prohibits any movement commands that shorten the distance between the two cranes, and the operator in the central control room cannot manually intervene to command the two stacker cranes to continue traveling towards each other.

[0042] Third, if the two stackers are running in opposite directions (i.e., the distance between the two machines increases), or running in the same direction and the speed of the front machine is not lower than the speed of the rear machine (i.e., the distance between the two machines remains unchanged or increases), the system determines that it is in a safe state and allows the equipment to continue to operate normally in the current state.

[0043] Fourth, when the distance between the two vehicles returns to more than 17m (i.e., 15m plus 2m backlash distance), the system automatically deactivates the safety protection state and restores normal driving control permissions.

[0044] In strip-shaped material yards, high-level stackers are typically cantilever stackers, while low-level reclaimers are typically semi-gantry scraper reclaimers. When they operate on adjacent tracks, there is a possibility of overlapping operations, requiring more stringent collision avoidance control. The artificial intelligence control system uses a real-time positioning monitoring system to acquire the stacker's position A and the reclaimer's position C in real time at a refresh rate of no less than 10Hz. The system simultaneously acquires the stacker's conveyor belt's operating status signals, including belt operating frequency, belt operating direction, and belt start / stop status.

[0045] (i) The intelligent determination system for the stacking operation area intelligently determines the current stacking operation area based on the operating status of the stacker conveyor belt. When the stacker conveyor belt is in operation, the area extending 20m to the left and right of the current position of the stacker is marked as the active stacking operation area. The system predicts the reclaimers that may pass through this area and issues an early warning to ensure that the normal operation of unrelated reclaimers is not affected.

[0046] (II) Two-stage deceleration protection: Stage 1 (Length < 10m): When the horizontal clearance between the stacker and the reclaimer decreases to 10m, the frequency converters of the stacker and reclaimer's travel systems simultaneously reduce from the rated frequency of 50Hz to 5Hz over a 3-second ramp time, achieving slow, decelerated movement. At this time, both vehicles operate at a safe low speed (approximately 3m / min), and the operator can see on the central control room monitoring screen that the two vehicles are constantly approaching each other, but their speed is already limited. Stage 2 (Length < 5m): When the Length further decreases to within 5m, the system triggers a safety interlock, simultaneously cutting off the forward drive of the stacker and reclaimer's travel systems, retaining only the backward drive capability. The central control room HMI displays a message stating "The stacker and reclaimer have reached a safe distance; movement is prohibited," forcibly stopping their relative movement.

[0047] (III) Control of the Reclaimer Crossing the Stacking Operation Area If the reclaimer needs to cross the current stacking operation area, the system sets strict preconditions. The system continuously monitors the operation status of the stacker belt. Only after the stacker belt has completely stopped and a 3-second delay has been confirmed, is the reclaimer allowed to perform the crossing operation at a low speed not exceeding 5Hz. During the crossing, the obstacle avoidance radar continuously monitors the distance between the two vehicles. If the distance is less than 5m again, an emergency stop is immediately executed.

[0048] Dynamic interlocking logic is built into the logic control module of the artificial intelligence control system. Specifically, it includes the following three levels: (i) Interlocking between the walking system and the stacker-reclaimer mechanism: Establish a dual interlocking relationship between the walking system and the stacker and reclaimer mechanisms, consisting of electrical and logical interlocks. When the system detects an abnormal operating state of the stacker mechanism (such as a cantilever belt conveyor or a stacker chute) or the reclaimer mechanism (such as a scraper chain), it automatically cuts off the forward drive enable of the walking system while keeping the reverse drive available, allowing the stacker-reclaimer to exit the danger zone.

[0049] (ii) Interlock between the travel system and the pitch mechanism: Establish an interlock relationship between the travel system and the pitch mechanism. When the system detects that the pitch angle of the pitch mechanism exceeds the limit or the pitch drive motor current is abnormal, it automatically locks the drive output in all directions of the travel system to prevent collision with the high-level stacker in the state of pitch mechanism malfunction.

[0050] (III) Dual Redundancy Detection of Obstacle Avoidance Radar and Machine Vision The obstacle avoidance radar and machine vision unit system form a dual redundancy detection mechanism. When the obstacle avoidance radar detects a person or obstacle entering the designated electronic fence area around the track, the system immediately triggers an alarm and automatically locks the walking system drive. When the machine vision unit system also detects the same target at the same time, the system determines it as a valid obstacle, forcibly executes an emergency stop, and locks all mechanism actions. When one sensor detects a target while the other does not, the system enters a warning state, reduces its walking speed, and intensifies monitoring. After the fault or obstacle is cleared, and after manual confirmation or automatic system confirmation (obstacle signal disappears and no new signal for 10 seconds), the interlock is automatically released, and normal operation resumes.

[0051] This invention has been successfully applied in the unmanned system of the No. 1 enclosed strip-shaped material storage yard of a 2×1,000 MW capacity expansion and upgrade project. The yard is equipped with two fully functional cantilever stackers and two semi-gantry scraper reclaimers. The enclosed length of the yard is approximately 220m, and the span is approximately 120m. The project implementation process is as follows: Phase 1: Equipment Installation and Commissioning (120 days). Install electrical components for the real-time positioning monitoring system at relevant locations on the stacker-reclaimers and on the connecting feed and discharge conveyor legs. This includes the Gray busbar (laid along the entire track, approximately 600m), RFID readers for trolley positioning (2 per stacker-reclaimer, 8 in total), RFID markers along the line (1 every 60m, 10 in total), absolute encoders (1 set per stacker-reclaimer wheel, 4 sets in total), inclinometers (2 at the base of the rake plate on each reclaimer, 4 in total), obstacle avoidance radar (4 per stacker-reclaimer, 16 in total), and level radar (4 per rake plate on each reclaimer, 8 in total). Simultaneously, complete the laying of the fiber optic ring network and the installation of the wireless bridge for the communication system.

[0052] Phase Two: System Integration and Debugging (60 days). Complete the integration of all sensor signals into the AI ​​control system, perform parameter tuning of the multi-source fusion positioning algorithm, and initialize the Kalman filter. Complete the calibration of the 3D stockpile modeling system and the deployment of the Tree.js rendering engine. Complete the software programming of all safety control logic and the download and debugging of the DCS program.

[0053] Phase 3: No-load trial operation (15 days). Under no-material conditions, test the automatic walking function of the stacker-reclaimer item by item according to the planned path to verify the correctness and reliability of the graded deceleration control, anti-collision control and dynamic interlock logic.

[0054] Phase 4: Load-bearing trial operation (30-day duration). Verify the system's safety control effectiveness under actual stacking and reclaiming operation conditions.

[0055] Application Results: After system commissioning, the central control room's AI control system monitors, updates, and stores the stacker-reclaimer's position data in real time, with a positioning error of no more than 5cm. The stacker-reclaimer automatically completes its movement according to the path planned by the AI ​​control system. When the stacker-reclaimer moves towards the end of the track, it automatically decelerates to 5Hz at 15m and to 2Hz at 3m, stopping precisely. Collision protection is automatically triggered when two stackers on the same track are less than 15m apart. The high-level stacker and low-level reclaimer automatically decelerate when less than 10m apart and automatically interlock and stop when less than 5m apart. The entire system achieves full-condition, multi-level redundant protection. The original manual operation mode required 16 operators (3 on duty and 1 on standby per machine); now, only 4 monitoring personnel (3 on duty and 1 on standby) are needed in the central control room to monitor all equipment. The system operates stably and reliably, with no safety incidents occurring in the movement system.

[0056] VI. Workflow Summary The complete workflow of the safety control method described in this invention is as follows: Step S1: Install the relevant electrical components of the real-time positioning monitoring system at the relevant locations of the stacker-reclaimer equipment and on the support legs of the connected infeed and outfeed conveyor belts; Step S2: The artificial intelligence control system plans the optimal operation path based on the location of the stacker-reclaimer, material pile shape data, and task requirements. Step S3: The stacker-reclaimer automatically completes its walking motion according to the path planned by the artificial intelligence control system; Step S4: When the stacker-reclaimer moves toward the end of the track, it implements two-stage deceleration control based on the fusion positioning results until it stops safely at the predetermined position; Step S5: When the stacker-reclaimer passes its respective cable reel overturning device, deceleration control is implemented based on the fusion positioning result to ensure the safety of the special cable when it travels with the vehicle; Step S6: Implement intelligent anti-collision control based on the direction of travel between the two stackers on the same track; Step S7: Implement anti-collision control between the high-level stacker and the low-level reclaimer based on the stacking area determination and two-level distance thresholds; Step S8: Dynamic interlocking is implemented between the walking system and the stacking and reclaiming mechanism and the pitching mechanism, and the obstacle avoidance radar and machine vision form a double redundancy detection; Step S9: Repeat the above process until the entire stockpiling area is full of material or all material has been removed.

[0057] In summary, this invention, through the design of a reasonable real-time positioning monitoring system and the cooperation of relevant electrical components, designs a full-condition, multi-level redundant protection logic. By utilizing an artificial intelligence control system and AI intelligent algorithms, it reliably ensures the safe movement of the stacker-reclaimer system in the unmanned bulk material storage system of a closed strip storage yard under complex working conditions.

[0058] It is understood that the systems, devices, and storage media provided in the embodiments of the present invention correspond to the methods provided in the embodiments of the present invention, and the explanations, examples, and beneficial effects of the relevant content can be referred to the corresponding parts of the above methods.

[0059] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0060] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A safety control method for the walking system of an unattended stacker-reclaimer in a strip material yard, characterized in that, include: The real-time positioning monitoring system, including the Gray busbar, trolley positioning RFID reader and absolute encoder, is used to measure the position and travel speed of the stacker-reclaimer in the material yard. The communication system, connected to the artificial intelligence control system and stacker-reclaimer equipment, is used to enable data interaction between the system and the stacker-reclaimer equipment and related electrical components in the bar stockyard. The artificial intelligence control system has a built-in multi-machine collaborative control unit, path planning unit and intelligent decision-making unit, which is used to receive and integrate multi-source sensing data, generate work task allocation schemes, work path planning and material stacking and picking strategies, and issue operation instructions. Based on the real-time positioning monitoring system, the actual distance between the stacker-reclaimer and the designated position on the track is obtained, and the following safety control logic is executed based on this actual distance: When the stacker-reclaimer moves toward the end of the track and the actual distance is not greater than the first distance threshold, the frequency converter of the walking system drops to the first frequency; when the actual distance is not greater than the second distance threshold, the frequency converter further drops to the second frequency until it stops at a predetermined position, where the second distance threshold is less than the first distance threshold and the second frequency is less than the first frequency. When the stacker-reclaimer moves to within the first distance threshold of the cable reel overturning device, the frequency converter drops to the first frequency; Collision avoidance control between two stackers on the same track: real-time acquisition of the precise position of the two stackers, calculation of the distance between the two vehicles, and when the distance is less than the first distance threshold, determination of whether to trigger safety protection based on the direction of the vehicle's movement; Collision avoidance control between the high-level stacker and the low-level reclaimer: The precise positions of the stacker and the reclaimer are acquired in real time, and the horizontal clearance is calculated. When the clearance is less than the third distance threshold, the operating frequency is smoothly reduced to the first frequency. When the clearance is less than the fourth distance threshold, a safety interlock is triggered. The fourth distance threshold is less than the third distance threshold.

2. The safety control method for the unmanned stacker-reclaimer walking system of the strip material yard according to claim 1, characterized in that, In the real-time positioning monitoring system, the Gray busbar, the trolley positioning RFID reader, and the absolute encoder constitute a multi-source fusion positioning architecture. The positioning result of the Gray busbar is used as the main reference to output the full track position. The high-frequency pulse data of the absolute encoder is used to fill the positioning refresh rate. The positioning result is periodically corrected by RFID landmarks deployed along the track to eliminate wheel slippage or encoder cumulative error.

3. The safety control method for the unmanned stacker-reclaimer walking system of the strip material yard according to claim 2, characterized in that, The multi-source fusion positioning architecture uses a data fusion algorithm to perform synchronous registration, outlier removal, and dynamic weighted fusion of three types of sensor signals. It also dynamically allocates fusion weights based on the real-time signal quality of each sensor and has built-in automatic redundancy switching logic when a single sensor fails.

4. The safety control method for the unmanned stacker-reclaimer walking system of the strip material yard according to claim 1, characterized in that, The artificial intelligence control system also includes; The data acquisition and preprocessing module is used to collect material pile information and motor current data and perform preprocessing. The data processing module is used to smooth the point cloud and extract features from the preprocessed material pile information, and to render the material pile shape in 3D, as well as to filter the motor current data to obtain the motor temperature data. The model training module is used to train the equipment fault diagnosis model; The logic control module is used to generate stacking and reclaiming path planning instructions and walking status safety control instructions based on the processed data.

5. The safety control method for the unmanned stacker-reclaimer walking system of the strip material yard according to claim 1, characterized in that, It also includes a multi-source environmental perception subsystem consisting of obstacle avoidance radar, material level radar, and inclinometer; the obstacle avoidance radar is installed around the stacker-reclaimer body to detect the distance between the stacker-reclaimer and the end of the track, adjacent equipment, and surrounding obstacles; the material level radar is installed on the reclaimer to monitor the height of the material pile; the inclinometer is installed on the reclaimer's rake plate to monitor the rake plate's pitch angle.

6. The safety control method for the unmanned stacker-reclaimer walking system of the strip material yard according to claim 1, characterized in that, The communication system includes wired communication links and wireless communication links. Under normal operating conditions, wired communication is the main link and wireless communication is the hot standby link. When the main link is interrupted, it automatically switches to the standby link to achieve redundant backup communication with the artificial intelligence control system.

7. The safety control method for the unmanned stacker-reclaimer walking system of the strip material yard according to claim 1, characterized in that, It also includes dynamic interlock logic: establishing an interlock relationship between the walking system and the stacking and reclaiming mechanism and the pitching mechanism. When the stacking and reclaiming mechanism or the pitching mechanism is in an abnormal state, or when the obstacle avoidance radar and the machine vision unit form a dual detection system to determine that there are people or obstacles around the track, the operation of the corresponding mechanism is automatically locked, and the interlock is automatically released after the abnormality is eliminated.

8. The safety control method for the unmanned stacker-reclaimer walking system of the strip material yard according to claim 1, characterized in that, The stacker-reclaimer is equipped with travel limit switches and extreme limit switches. Corresponding trigger blocks are installed at the predetermined stopping position on the track and at the end of the track. The travel limit switches and extreme limit switches, together with the graded deceleration control of the frequency converter and the software stop command of the artificial intelligence control system, form multiple redundant protections.

9. The safety control method for the unmanned stacker-reclaimer walking system of the strip material yard according to claim 1, characterized in that, In the anti-collision control between two stackers on the same track, when the distance between the two vehicles is less than the first distance threshold, if the direction of travel of the main vehicle will cause the distance between the two vehicles to decrease further, the safety protection will be triggered and relative travel will be prohibited; if the direction of travel increases the distance between the two vehicles, the equipment is allowed to operate normally.

10. The safety control method for the unmanned stacker-reclaimer walking system of the strip material yard according to claim 1, characterized in that, In the anti-collision control between the high-level stacker and the low-level reclaimer, the system determines the current stacking operation area based on the running status of the stacker belt and predicts the reclaimers that may pass through the area; when the reclaimer crosses the stacking operation area, it can only be executed after the stacker belt has stopped running; the first distance threshold is greater than the third distance threshold, the third distance threshold is greater than the fourth distance threshold, and the first frequency is higher than the second frequency.

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