A rectangular stockyard stacker-reclaimer collision prevention method and system

Abstract

The application discloses a rectangular stockyard stacker-reclaimer collision prevention method and system, belongs to the technical field of stacker-reclaimer anti-collision analysis, simplifies detection and calculation of three-dimensional position coordinate positions of a cantilever end of a stacker and a top end of a reclaimer rake in a rectangular stockyard, and after checking longitudinal and vertical space coordinates, only accurate measurement of horizontal positions of the two is needed to build software safety anti-collision functions of the two vehicles; a set of laser ranging sensors is added to each stacker-reclaimer, and the set of laser ranging sensors is used for tracking and redundancy backup; position detection sensors are evenly arranged beside tracks on both sides of the stockyard, and encoder data on traveling wheels of the stacker-reclaimer is compared and checked; in addition to building software installation anti-collision functions based on accurate detection of equipment coordinate positions, a set of ultrasonic ranging and rope anti-collision systems is arranged on a large arm of the stacker-reclaimer, and the set of ultrasonic ranging and rope anti-collision systems together form a safety anti-collision system of the rectangular stockyard stacker-reclaimer, and create a fundamental guarantee for safe and stable operation of unattended operation of the stockyard.

Description

Technical Field

[0001] This invention belongs to the field of collision prevention analysis technology for stacker-reclaimers, and more specifically, relates to a collision prevention method and system for stacker-reclaimers in rectangular stockyards. Background Technology

[0002] During the operation of stacker-reclaimers in rectangular stockyards, the stacker and reclaimer need to be frequently switched between locations. When the two machines are being switched, there is a long area between the stacker boom and the reclaimer rake that may collide. This is especially true in unattended stockyards where there are no traditional operators to control the distance between the machines. Once a collision occurs, the economic losses will be enormous. Therefore, it is essential to design a stable and reliable anti-collision system between stacker-reclaimers. Summary of the Invention

[0003] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention proposes a collision prevention method and system for stacker-reclaimers in rectangular stockyards, which is used to realize a stable and reliable collision prevention system between stacker-reclaimers.

[0004] To achieve the above objectives, according to one aspect of the present invention, a collision prevention method for a rectangular stockpile stacker-reclaimer is provided, comprising:

[0005] Absolute rotary encoders are installed on the wheels of the stacker and the reclaimer to measure the horizontal X-axis position of the stacker and the reclaimer in the three-dimensional coordinate system of the rectangular stockpile in real time, thereby obtaining the horizontal coordinate position of the foremost end of the stacker cantilever in the three-dimensional coordinate system of the rectangular stockpile and the horizontal coordinate position of the top of the reclaimer rake in the three-dimensional coordinate system of the rectangular stockpile.

[0006] Laser rangefinders are installed at both ends of the moving track of the material reclaimer rake to locate the real-time position of the frontmost baffle of the material reclaimer rake on the Y-axis. An inclination sensor is installed at the hinge of the stacker arm to detect the pitch angle of the stacker arm in real time.

[0007] Based on the real-time position of the reclaimer's rake, the PLC on the reclaimer calculates the projection of the top of the reclaimer's rake onto the rectangular stockpile, thereby finding the vertical Y-axis position of the top of the reclaimer's rake on the three-dimensional coordinate system of the rectangular stockpile. Based on the pitch angle of the stacker's boom, the PLC on the stacker calculates the projection of the foremost point of the stacker's boom onto the rectangular stockpile, thereby finding the vertical Y-axis position of the foremost point of the stacker's boom on the three-dimensional coordinate system of the rectangular stockpile.

[0008] The minimum protection distance for preventing collisions is set by the horizontal and vertical coordinate positions of the front end of the stacker boom in the three-dimensional coordinate system of the rectangular stockpile and the horizontal and vertical coordinate positions of the top of the reclaimer rake in the three-dimensional coordinate system of the rectangular stockpile, thereby achieving the first level of anti-collision function.

[0009] Raise the stacker boom to its maximum elevation angle and move the reclaimer rake to its initial working position. Allow the stacker to cross over the reclaimer and verify the safe distance between the stacker boom and the reclaimer rake in the Z-axis direction of the three-dimensional coordinate system of the rectangular stockpile. Adjust the upper limit position of the stacker's elevation and the upper limit position of the reclaimer rake until the safe protection distance is met.

[0010] Several ultrasonic ranging sensors are installed on both sides of the stacker boom to detect objects on both sides of the stacker boom in real time during shunting and material placement operations. By setting the anti-collision distance, the second level of anti-collision function of the stacker-reclaimer is realized.

[0011] A set of anti-collision pull rope sensors is installed on each side of the stacker boom, extending a preset distance from the belt conveyor, as the third level of anti-collision function for the stacker and reclaimer.

[0012] In some alternative implementations, the absolute rotary encoders of the stacker and reclaimer are mounted on an auxiliary wheel, the wheel width of which is greater than the track width. The horizontal coordinate X-axis position of the stacker in the three-dimensional coordinate system of the rectangular stockpile, measured by the encoder, is added to the horizontal distance from the stacker wheel to the projection of the cantilever onto the plane coordinate of the rectangular stockpile to obtain the horizontal coordinate position of the foremost end of the stacker cantilever in the three-dimensional coordinate system of the rectangular stockpile. The horizontal coordinate X-axis position of the reclaimer in the three-dimensional coordinate system of the rectangular stockpile, measured by the encoder, is added to the horizontal distance from the reclaimer wheel to the projection of the rake onto the plane coordinate of the rectangular stockpile to obtain the horizontal coordinate position of the top of the reclaimer rake in the three-dimensional coordinate system of the rectangular stockpile.

[0013] In some alternative implementations, the real-time position of the front end of the material reclaimer rake on the Y-axis is obtained by subtracting the distance from the vertical projection of the front end of the material reclaimer rake to the Y-axis coordinate corresponding to the position of the material reclaimer track from the real-time position of the front end of the material reclaimer rake on the Y-axis.

[0014] In some alternative implementations, by placing the cantilever in a horizontal position and using a plumb line to find the corresponding point of the cantilever's foremost tip in the rectangular stockpile when the cantilever is in a horizontal position, the Y-axis position Y0 of the cantilever's foremost tip in the rectangular stockpile coordinate system when the cantilever is in a horizontal position is obtained from the distance between the corresponding point of the cantilever's foremost tip in the rectangular stockpile and the vertical projection onto the track. The real-time Y-axis position of the cantilever's foremost tip is obtained by Y = Y0 * cosA, where A is the pitch angle of the stacker cantilever.

[0015] In some alternative implementations, laser rangefinders are redundantly installed on the stacker and reclaimer as backup position measurement data, which are tracked and calibrated in real time. If the encoder data is abnormal, the laser rangefinder is immediately switched to be used.

[0016] In some alternative implementations, several position verification sensors are evenly set on the tracks on both sides of the stockyard to compare and verify the encoder data on the wheels of the stacker and reclaimer. The fixed coordinate values ​​of the verification points are then assigned to the encoders to eliminate encoder measurement errors.

[0017] In some alternative implementations, ultrasonic ranging sensors on the stacker boom are mounted near the ends and the middle, respectively.

[0018] In some optional implementations, the horizontal coordinate distance protection of the first-level anti-collision function is set with two protection levels. If the stacker is in shunting mode, when the first-level anti-collision distance is reached, the reclaimer's rake returns to the starting position, the trolley stops moving, and the stacker safely crosses the reclaimer at shunting speed. If the stacker is in working mode, the reclaimer is working normally. When the first-level anti-collision distance is reached, the stacker turns around and moves. If the safe distance continues to shrink and reaches the second-level protection distance, the stacker immediately reports a fault and stops moving.

[0019] In some optional implementations, the minimum protection distance for collision prevention in the first-level collision avoidance function is determined as follows:

[0020] The minimum protection distance in the Y direction was verified by on-site shunting measurements.

[0021] The minimum protection distance in the X direction is determined by measuring the stacker's travel distance from its operating speed to a complete stop when the stacker is stopped in shunting mode using the frequency converter driven by the stacker's wheel motor. Then, a certain distance is added to the stacker's travel distance to determine the minimum safe distance between the stacker and reclaimer.

[0022] According to another aspect of the present invention, a collision prevention system for a rectangular stockpile stacker-reclaimer is provided, comprising:

[0023] Absolute rotary encoders are installed on the wheels of the stacker and reclaimer respectively to measure the horizontal X-axis position of the stacker and reclaimer in the three-dimensional coordinate system of the rectangular stockpile in real time, thereby obtaining the horizontal coordinate position of the foremost end of the stacker cantilever in the three-dimensional coordinate system of the rectangular stockpile and the horizontal coordinate position of the top of the reclaimer rake in the three-dimensional coordinate system of the rectangular stockpile.

[0024] Laser rangefinders are installed at both ends of the moving track of the material reclaimer rake to locate the real-time position of the frontmost baffle of the material reclaimer rake on the Y-axis.

[0025] An inclination sensor installed at the hinge of the stacker boom is used to detect the pitch angle of the stacker boom in real time.

[0026] The PLC on the reclaimer is used to calculate the projection of the top of the reclaimer's rake onto the rectangular stockpile based on the real-time position of the rake, thereby finding the vertical Y-axis position of the top of the rake on the three-dimensional coordinate system of the rectangular stockpile.

[0027] The PLC on the stacker is used to calculate the projection of the front end of the stacker boom onto the rectangular stockpile based on the pitch angle of the stacker boom, thereby finding the vertical Y-axis position of the front end of the stacker boom on the three-dimensional coordinate system of the rectangular stockpile.

[0028] The first-level anti-collision module is used to set the minimum protection distance to prevent collisions by using the horizontal and vertical coordinate positions of the front end of the stacker's cantilever in the three-dimensional coordinate system of the rectangular stockpile and the horizontal and vertical coordinate positions of the top of the reclaimer's rake in the three-dimensional coordinate system of the rectangular stockpile.

[0029] The Z-axis safety distance verification module is used to raise the stacker boom to its maximum elevation angle and move the reclaimer rake to its initial working position, allowing the stacker to cross the reclaimer. It verifies the safety distance between the stacker boom and the reclaimer rake in the Z-axis direction of the three-dimensional coordinate system of the rectangular stockpile. The module adjusts the upper limit position of the stacker's elevation and the upper limit position of the reclaimer rake until the safety protection distance is met.

[0030] The second-level anti-collision module is used to detect objects on both sides of the stacker boom in real time during shunting and material placement operations by installing several ultrasonic ranging sensors on both sides of the stacker boom. By setting the anti-collision distance, the second-level anti-collision function of the stacker-reclaimer is realized.

[0031] The third-level anti-collision module is used to provide a third level of anti-collision protection for the stacker and reclaimer by installing a set of anti-collision pull rope sensors on each side of the stacker's cantilever, which extend a preset distance from the belt conveyor.

[0032] In some alternative implementations, the absolute rotary encoders of the stacker and reclaimer are mounted on an auxiliary wheel, the wheel width being greater than the track width.

[0033] In some alternative implementations, laser rangefinders are redundantly installed on the stacker and reclaimer as backup position measurement data, which are tracked and calibrated in real time. If the encoder data is abnormal, the laser rangefinder is immediately switched to be used.

[0034] In some alternative implementations, several position verification sensors are evenly arranged on the tracks on both sides of the stockyard to compare and verify the encoder data on the wheels of the stacker and reclaimer.

[0035] In some alternative implementations, ultrasonic sensors on the stacker boom are mounted near the ends and the middle, respectively.

[0036] In some optional implementations, the horizontal coordinate distance protection of the first-level anti-collision function is set with two protection levels. If the stacker is in shunting mode, when the first-level anti-collision distance is reached, the reclaimer's rake returns to the starting position, the trolley stops moving, and the stacker safely crosses the reclaimer at shunting speed. If the stacker is in working mode, the reclaimer is working normally. When the first-level anti-collision distance is reached, the stacker turns around and moves. If the safe distance continues to shrink and reaches the second-level protection distance, the stacker immediately reports a fault and stops moving.

[0037] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0038] 1. The detection and calculation of the three-dimensional position coordinates at the cantilever end of the stacker and the top of the material rake of the reclaimer in a rectangular stockpile are simplified. After verifying the longitudinal and vertical spatial coordinates, only the horizontal position of the two needs to be accurately measured to build the safety anti-collision function of the stacker-reclaimer.

[0039] 2. To achieve accurate measurement and reliable data of the horizontal position of the stacker-reclaimer, a set of laser rangefinder sensors was added to each stacker-reclaimer for tracking and redundancy.

[0040] 3. To achieve accurate measurement and reliable data of the horizontal position of the stacker-reclaimer, several position verification sensors are evenly installed on both sides of the track in the stockyard to compare and verify the encoder data on the wheels of the stacker-reclaimer.

[0041] 4. In addition to building software-based anti-collision functions based on precise detection of equipment coordinates, an ultrasonic ranging and rope anti-collision system were installed on the stacker boom, which together formed the safety anti-collision system of the rectangular stockpile stacker-reclaimer, providing a fundamental guarantee for the safe and stable operation of the stockpile without human intervention. Attached Figure Description

[0042] Figure 1 This is a schematic flowchart of a collision prevention method for a rectangular stockpile stacker-reclaimer provided in an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the installation of an encoder and laser rangefinder for a stacker / reclaimer provided in an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of the installation of a laser rangefinder and a position verification sensor for a material handling machine rake, provided in an embodiment of the present invention.

[0045] Figure 4 This is a schematic diagram of the installation of a stacker cantilever tilt sensor, an ultrasonic ranging sensor, and an anti-collision rope provided in an embodiment of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0047] This invention provides an automated device and safety protection control system for preventing collisions with stacker-reclaimers, mainly including automated sensors and a safety anti-collision control program.

[0048] like Figure 1 As shown, the technical solution adopted in this invention is:

[0049] Step 1: As Figure 2 As shown, absolute rotary encoders are installed on the wheels of the stacker and reclaimer to measure the horizontal X-axis position of the stacker and reclaimer in the three-dimensional coordinate system of the rectangular stockpile in real time. Several position calibration sensors are also added to automatically calibrate the position of the stacker and reclaimer.

[0050] In this embodiment of the invention, after measuring the horizontal X-axis position of the stacker and reclaimer in the three-dimensional coordinate system of the rectangular stockpile, the horizontal coordinate position of the foremost end of the stacker cantilever in the three-dimensional coordinate system of the rectangular stockpile can be obtained by adding the absolute coordinate value measured by the encoder to the horizontal distance from the stacker's wheels to the projection of the cantilever onto the plane coordinate of the rectangular stockpile (obtained by actual measurement using a plumb line); the horizontal coordinate position of the top of the reclaimer's rake in the three-dimensional coordinate system of the rectangular stockpile can be obtained by adding the absolute coordinate value measured by the encoder to the horizontal distance from the reclaimer's wheels to the projection of the rake onto the plane coordinate of the rectangular stockpile (obtained by actual measurement using a plumb line).

[0051] In this embodiment of the invention, the number of position verification sensors installed can be determined according to actual needs.

[0052] In this embodiment of the invention, the positions of the stacker and reclaimer are calibrated using a position verification sensor, which can be achieved in the following way:

[0053] Position verification sensors can be evenly distributed according to the length of the stockpile track. For example, if the total track length is 240 meters, in this embodiment of the invention, a position verification sensor is placed at a interval of 40 meters, for a total of 7 sensors. Induction plates are added to the stacker and reclaimer. The software program position verification principle is that at each fixed verification point (i.e., the location of the position verification sensor), the fixed coordinate value of the verification point is assigned to the encoder, eliminating the measurement error caused by the measuring wheel falling off the track or jumping, and ensuring the accuracy of the measurement data.

[0054] Step 2: As Figure 3 As shown, laser rangefinders are installed at both ends of the moving track of the material reclaimer's rake to accurately locate the position of the material reclaimer's rake. Figure 4 As shown, an tilt sensor is installed at the hinge joint of the stacker boom to detect the pitch angle of the stacker boom in real time.

[0055] Step 3: Calculate the projection of the top of the reclaimer's rake onto the rectangular stockpile using the PLC on the reclaimer, thereby finding the vertical Y-axis position of the top of the reclaimer's rake on the three-dimensional coordinate system of the rectangular stockpile. Calculate the projection of the front end of the stacker's cantilever onto the rectangular stockpile using the PLC on the stacker, thereby finding the vertical Y-axis position of the front end of the stacker's cantilever on the three-dimensional coordinate system of the rectangular stockpile.

[0056] In this embodiment of the invention, the Y-axis position of the material reclaimer rake is determined as follows:

[0057] like Figure 3 As shown, a trolley-to-center distance laser sensor is installed at both ends of the material rake moving track of the material reclaimer. First, the real-time position of the frontmost baffle of the material rake on the Y-axis is measured. Then, the distance between the vertical projection of the frontmost of the material rake and the Y-axis coordinate corresponding to the position of the material rake track is subtracted, thus calculating the real-time position of the frontmost of the material rake on the Y-axis of the three-dimensional coordinate system of the rectangular stockpile.

[0058] In this embodiment of the invention, the Y-axis coordinate position of the foremost end of the stacker boom can be achieved in the following way:

[0059] By placing the cantilever in a horizontal position (pitch angle of 0 degrees), suspending a plumb line, finding the corresponding point in the rectangular stockpile, and then using a handheld laser rangefinder to measure the distance between this point and the vertical projection onto the track, the Y-axis position of the cantilever's foremost point in the stockpile coordinate system is obtained. The real-time Y-axis position of the cantilever's foremost point during shunting and actual fabric placement is calculated using the tilt angle A measured by the pitch angle sensor and the inverse cosine of the horizontal Y-axis coordinate Y0, i.e., Y' = Y0 * cosA.

[0060] Step 4: Set the minimum protection distance to prevent collisions by using the horizontal and vertical coordinate positions of the front end of the stacker boom in the three-dimensional coordinate system of the rectangular stockpile and the horizontal and vertical coordinate positions of the top of the reclaimer rake in the three-dimensional coordinate system of the rectangular stockpile, so as to achieve the first level of anti-collision function.

[0061] In this embodiment of the invention, step S4 includes:

[0062] Since the stacker crane crossing the reclaimer only occurs during stacker-reclaimer relocation, the distances on the XYZ coordinates of the stacker crane's cantilever tip and the reclaimer's rake tip need to be verified. The minimum distance in the YZ direction is verified through on-site measurement during relocation; once it is met, it is acceptable. Most importantly, it is crucial to monitor in real-time that the stacker crane and reclaimer maintain a minimum collision avoidance distance in their horizontal positions. This is because under most normal stacker-reclaimer operating conditions, the stacker crane's cantilever is not at its highest position, and the reclaimer's rake will also move back and forth on the Y-axis track. The method for setting the minimum protection distance on the horizontal coordinates is as follows: Measure the stacker crane's travel distance (slippage distance) from its operating speed to a complete stop when the stacker crane stops in relocation mode (speed higher than operating speed) using the frequency converter driven by the stacker's wheel motor. Then, add a certain distance (e.g., 2m) to this measurement as the minimum software safety distance between the stacker and reclaimer. Once the coordinate difference between the stacker and the reclaimer in the horizontal position is less than this value, a signal is sent to trip and stop the stacker and reclaimer.

[0063] Step 5: Raise the stacker boom to the maximum elevation angle and move the reclaimer rake to the initial working position, i.e., the upper limit position near the cab end. Let the stacker slowly cross the reclaimer and verify the safe distance between the stacker boom and the reclaimer rake in the Z-axis direction of the three-dimensional coordinate system of the rectangular stockpile. Adjust the upper limit position of the stacker's elevation and the upper limit position of the reclaimer rake until the safe protection distance is met.

[0064] In this embodiment of the invention, the method for verifying the safe distance in the Z-axis direction is as follows: the material rake trolley of the reclaimer is moved to the upper limit position near the cab end, the stacker boom is raised to the maximum pitch angle position, and then the stacker is slowly allowed to pass over the reclaimer. The distance between the front end of the stacker boom and the top of the material rake of the reclaimer when they approach each other is monitored. If the distance is insufficient, the machine is stopped immediately, and the safe protection distance of both is met by adjusting the upper limit position of the stacker pitch or the upper limit position of the material rake of the reclaimer.

[0065] Step 6: As Figure 4 As shown, two ultrasonic ranging sensors are installed on each side of the stacker boom to detect objects (including material rakes) on both sides of the stacker boom in real time during shunting and material placement operations. The collision avoidance distance is set by software to realize the second level of collision avoidance function of the stacker-reclaimer.

[0066] In this embodiment of the invention, based on the stacker wheel motor drive frequency converter stopping in shunting mode (speed higher than working speed), the stacker travels from working speed to complete stop, and the actual distance (slippage distance) of the stacker is measured. Then, a certain distance (such as 2m) is added to this to serve as the minimum software safety distance set between the stacker and reclaimer.

[0067] Step 7: As Figure 4As shown, a set of anti-collision pull rope sensors is installed on each side of the stacker's cantilever, extending a preset distance from the belt conveyor, serving as the third level of anti-collision function for the stacker and reclaimer.

[0068] The preset distance at which the anti-collision pull rope sensor extends out of the belt conveyor can be determined according to actual needs, such as about 1 meter.

[0069] According to a preferred embodiment of the present invention, the absolute rotary encoders of the stacker and the reclaimer are mounted on an auxiliary wheel with a wheel width slightly larger than the track width, so as to avoid deviations in measurement data caused by track deformation leading to the auxiliary wheel falling off the track or being suspended in the air.

[0070] like Figure 2 As shown in the preferred embodiment of the present invention, in order to ensure data reliability, two sets of laser rangefinders are redundantly installed on the stacker and reclaimer as backup position measurement data, which are tracked and calibrated in real time. If the encoder data is abnormal, the laser rangefinder is immediately switched to be used.

[0071] like Figure 3 As shown in the preferred embodiment of the present invention, in order to ensure data accuracy, seven position verification sensors are evenly arranged on each side of the track of the stockpile to compare and verify the encoder data on the wheels of the stacker and reclaimer.

[0072] According to a preferred embodiment of the present invention, in order to ensure the effectiveness of the sensors, the ultrasonic sensors on the stacker boom are respectively installed near the ends and the middle.

[0073] The first-level anti-collision function of this invention has two levels of horizontal coordinate distance protection. If the stacker is in shunting mode, when the first level of anti-collision distance is reached, the reclaimer's rake returns to the starting position, the trolley stops moving, and the stacker safely passes the reclaimer at shunting speed. If the stacker is in working mode, the reclaimer is working normally. When the first level of anti-collision distance is reached, the stacker turns around and moves. If the safe distance continues to shrink and reaches the second level of protection distance, the stacker immediately reports a fault and stops moving.

[0074] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0075] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preventing collisions with a stacker-reclaimer in a rectangular stockpile, characterized in that, include: Absolute rotary encoders are installed on the auxiliary wheels of the stacker and reclaimer, with the wheel width greater than the track width. The horizontal X-axis position of the stacker and reclaimer in the three-dimensional coordinate system of the rectangular stockpile is measured in real time. The horizontal X-axis position of the stacker in the three-dimensional coordinate system of the rectangular stockpile is obtained by adding the horizontal distance from the stacker wheel to the projection of the cantilever onto the plane coordinate of the rectangular stockpile. Similarly, the horizontal X-axis position of the reclaimer in the three-dimensional coordinate system of the rectangular stockpile is obtained by adding the horizontal distance from the reclaimer wheel to the projection of the rake onto the plane coordinate of the rectangular stockpile. Laser rangefinders are installed at both ends of the moving track of the material reclaimer rake to locate the real-time position of the frontmost baffle of the material reclaimer rake on the Y-axis. An inclination sensor is installed at the hinge of the stacker arm to detect the pitch angle of the stacker arm in real time. Based on the real-time position of the reclaimer's rake, the PLC on the reclaimer calculates the projection of the rake's tip onto the rectangular stockpile, thus finding the vertical Y-axis position of the rake's tip in the three-dimensional coordinate system of the rectangular stockpile. Similarly, based on the pitch angle of the stacker's boom, the PLC on the stacker calculates the projection of the stacker's boom's foremost point onto the rectangular stockpile, thus finding the vertical Y-axis position of the stacker's boom's foremost point in the three-dimensional coordinate system of the rectangular stockpile. The real-time position of the rake's foremost baffle on the Y-axis is also measured. Subtracting the distance from the vertical projection of the rake's tip to the corresponding Y-axis coordinate of the rake track position, we obtain the real-time position of the rake's tip on the Y-axis of the rectangular stockpile's three-dimensional coordinate system. By placing the cantilever horizontally and using a plumb line to find the corresponding point of the cantilever's tip in the rectangular stockpile when the cantilever is horizontal, and based on the distance between this point and the vertical projection onto the track when the cantilever is horizontal, we obtain the Y-axis position Y0 of the cantilever's tip in the rectangular stockpile's coordinate system when the cantilever is horizontal. The real-time Y-axis position of the foremost end of the cantilever is obtained, where A is the pitch angle of the stacker cantilever. The minimum protection distance for preventing collisions is set by the horizontal and vertical coordinate positions of the front end of the stacker boom in the three-dimensional coordinate system of the rectangular stockpile and the horizontal and vertical coordinate positions of the top of the reclaimer rake in the three-dimensional coordinate system of the rectangular stockpile, thereby achieving the first level of anti-collision function. Raise the stacker boom to its maximum elevation angle and move the reclaimer rake to its initial working position. Allow the stacker to cross over the reclaimer and verify the safe distance between the stacker boom and the reclaimer rake in the Z-axis direction of the three-dimensional coordinate system of the rectangular stockpile. Adjust the upper limit position of the stacker's elevation and the upper limit position of the reclaimer rake until the safe protection distance is met. Several ultrasonic ranging sensors are installed on both sides of the stacker boom to detect objects on both sides of the stacker boom in real time during shunting and material placement operations. By setting the anti-collision distance, the second level of anti-collision function of the stacker-reclaimer is realized. A set of anti-collision pull rope sensors is installed on each side of the stacker boom, extending a preset distance from the belt conveyor, as the third level of anti-collision function for the stacker and reclaimer.

2. The method according to claim 1, characterized in that, Redundant laser rangefinders are installed on both the stacker and the reclaimer as backup position measurement data, and real-time tracking and calibration are performed. If the encoder data is abnormal, the laser rangefinder is immediately switched to be used.

3. The method according to claim 1, characterized in that, Several position verification sensors are evenly set on the tracks on both sides of the stockyard to compare and verify the encoder data on the wheels of the stacker and reclaimer. The fixed coordinate values ​​of the verification points are assigned to the encoder to eliminate the encoder's measurement error.

4. The method according to claim 1, characterized in that, The ultrasonic ranging sensors on the stacker boom are installed near the ends and in the middle.

5. The method according to claim 1, characterized in that, The first-level anti-collision function has two levels of horizontal coordinate distance protection. If the stacker is in shunting mode, when the first-level anti-collision distance is reached, the reclaimer's rake returns to the starting position, the trolley stops moving, and the stacker safely crosses the reclaimer at shunting speed. If the stacker is in working mode, the reclaimer is working normally. When the first-level anti-collision distance is reached, the stacker turns around and moves. If the safe distance continues to decrease and reaches the second-level protection distance, the stacker immediately reports a fault and stops moving.

6. The method according to claim 5, characterized in that, The method for determining the minimum protection distance for collision prevention in the first level of collision avoidance function is as follows: The minimum protection distance in the Y direction was verified by on-site shunting measurements. The minimum protection distance in the X direction is determined by measuring the stacker's travel distance from its operating speed to a complete stop when the stacker is stopped in shunting mode using the frequency converter driven by the stacker's wheel motor. Then, a certain distance is added to the stacker's travel distance to determine the minimum safe distance between the stacker and reclaimer.

7. A collision prevention system for a rectangular stockpile stacker-reclaimer, characterized in that, include: Absolute rotary encoders, with wheel widths greater than track widths, are installed on the auxiliary wheels of the stacker and reclaimer to measure the horizontal X-axis position of the stacker and reclaimer in the three-dimensional coordinate system of the rectangular stockpile in real time. The horizontal X-axis position of the stacker in the three-dimensional coordinate system of the rectangular stockpile is obtained by adding the horizontal distance from the stacker wheel to the projection of the cantilever onto the plane coordinate of the rectangular stockpile. Similarly, the horizontal X-axis position of the reclaimer in the three-dimensional coordinate system of the rectangular stockpile is obtained by adding the horizontal distance from the reclaimer wheel to the projection of the rake onto the plane coordinate of the rectangular stockpile. Laser rangefinders are installed at both ends of the moving track of the material reclaimer rake to locate the real-time position of the frontmost baffle of the material reclaimer rake on the Y-axis. An inclination sensor installed at the hinge of the stacker boom is used to detect the pitch angle of the stacker boom in real time. The PLC on the reclaimer is used to calculate the projection of the top of the reclaimer rake onto the rectangular stockpile based on the real-time position of the rake. This allows the reclaimer rake top to be located on the vertical Y-axis of the three-dimensional coordinate system of the rectangular stockpile. Specifically, the real-time position of the rake top on the Y-axis is obtained by subtracting the distance from the vertical projection of the rake top to the Y-axis of the rake track position from the measured real-time position of the rake front baffle. The PLC on the stacker crane is used to calculate the projection of the stacker crane's cantilever tip onto the rectangular stockpile based on the cantilever's pitch angle. This allows the PLC to determine the vertical Y-axis position of the stacker crane's cantilever tip in the three-dimensional coordinate system of the rectangular stockpile. Specifically, by placing the cantilever horizontally and using a plumb line to find the corresponding point of the cantilever tip in the rectangular stockpile when the cantilever is horizontal, the distance between this point and the vertical projection onto the track is used to obtain the Y-axis position Y0 of the cantilever tip in the rectangular stockpile coordinate system when the cantilever is horizontal. The real-time Y-axis position of the foremost end of the cantilever is obtained, where A is the pitch angle of the stacker cantilever. The first-level anti-collision module is used to set the minimum protection distance to prevent collisions by using the horizontal and vertical coordinate positions of the front end of the stacker's cantilever in the three-dimensional coordinate system of the rectangular stockpile and the horizontal and vertical coordinate positions of the top of the reclaimer's rake in the three-dimensional coordinate system of the rectangular stockpile. The Z-axis safety distance verification module is used to raise the stacker boom to its maximum elevation angle and move the reclaimer rake to its initial working position, allowing the stacker to cross the reclaimer. It verifies the safety distance between the stacker boom and the reclaimer rake in the Z-axis direction of the three-dimensional coordinate system of the rectangular stockpile. The module adjusts the upper limit position of the stacker's elevation and the upper limit position of the reclaimer rake until the safety protection distance is met. The second-level anti-collision module is used to detect objects on both sides of the stacker boom in real time during shunting and material placement operations by installing several ultrasonic ranging sensors on both sides of the stacker boom. By setting the anti-collision distance, the second-level anti-collision function of the stacker-reclaimer is realized. The third-level anti-collision module is used to provide a third level of anti-collision protection for the stacker and reclaimer by installing a set of anti-collision pull rope sensors on each side of the stacker's cantilever, which extend a preset distance from the belt conveyor.

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