Cable machine anti-collision control method for improving positioning precision by using combined positioning mode

Abstract

The application relates to a cable machine anti-collision regulation method for improving positioning precision by adopting a combined positioning mode, and the method comprises the following steps: adopting a collision detection method to detect the operation conflict between the cable machine and obstacles; judging the type of the obstacles according to the position coordinate information provided by a positioning server; for the case of fixed obstacles, calculating the braking distance and the required time for braking at the current speed of the cable machine, and comparing the braking distance and the required time with the cable machine warning distance and the warning time set by the system respectively; for the case of mobile obstacles, determining the adjustment object according to the cable machine anti-collision priority adjustment rule, and taking regulation measures for the adjustment object to prevent collision. The application detects possible collision conditions, realizes cable machine anti-collision regulation, and ensures that the cable machine can safely and efficiently operate in the construction process; the combined positioning mode is adopted, the combined positioning precision is high, the real-time performance is good, and the positioning precision reaches the centimeter level.

Description

Technical Field

[0001] This invention belongs to the field of hydropower engineering construction control, specifically relating to a cable crane anti-collision control method that uses a combined positioning approach to improve positioning accuracy. Background Technology

[0002] Cable cranes are widely used in my country's hydropower projects, especially in the construction of high arch dams, due to their ease of installation, high mobility, large lifting capacity, wide working range, and high mechanical efficiency. They are characterized by being erected once and functioning throughout the entire construction period. However, many of my country's high arch dams are built in high mountain and canyon areas with harsh weather conditions, narrow construction sites, frequent construction activities, and numerous overlapping operations, making cable crane collisions a significant risk. Currently, the main methods to prevent cable crane collisions in hydropower construction are assigning on-site cable crane supervisors and limiting the cable crane's working range. The former is susceptible to errors in subjective judgment regarding collisions due to factors such as the supervisor's location, observation distance, and weather conditions, and such personnel may also interfere with other on-site construction activities. Strictly defining the cable crane's working range not only affects construction scheduling and the efficiency of machinery but also fails to effectively prevent collisions during equipment transfer. Therefore, employing a high-precision positioning method for real-time monitoring of the cable crane, other construction machinery, and personnel during the cable crane construction process is crucial to effectively solve the cable crane collision problem. Chinese Patent CN103407898B, "Anti-collision Video Monitoring System for Cable Crane Hooks," discloses an anti-collision video monitoring system for cable crane hooks. This system utilizes a camera installed on the cable crane trolley to monitor the cable crane hook and the hoisted load in real time, transmitting the monitoring data wirelessly or via wired means to the operator's cab, thus providing the cable crane operator with a basis for anti-collision operations. Chinese Patent CN103693556B, "Real-time Monitoring and Positioning System for Cable Cranes," discloses a real-time positioning and monitoring system for cable cranes. This system receives GPS and BeiDou differential positioning signals in real time through a positioning antenna installed on the cable crane hook, thereby obtaining the position and spatial velocity information of the hoisted load. Chinese Patent CN102409678B, "GPS-based Collision Monitoring and Navigation Positioning Method for Dam Concrete Material Pipes," discloses a method that uses GPS to monitor the position of the cable crane hoist in real time and performs collision detection with the position information of obstacles at the construction site, while simultaneously planning a safe operating path for the cable crane hoist.

[0003] However, the above-mentioned cable crane positioning and collision avoidance methods have the following shortcomings: First, in high mountain and canyon areas where arch dams are being constructed, the satellite signals of GPS or other global positioning systems such as BeiDou are severely blocked, especially in river valley foundation pits where the number of visible satellites decreases drastically. When there are fewer than four satellites, the positioning accuracy of GPS, especially the vertical accuracy, will significantly decrease. Furthermore, the process of loading and unloading the cable crane into the dam is a period when collisions are likely to occur between the cable crane and other dam surface construction machinery and personnel, requiring higher positioning accuracy. Secondly, during cable crane construction, objects that may collide with the cable crane can be divided into fixed obstacles and moving obstacles. Fixed obstacles include dam body concrete blocks, dam surface formwork, and certain temporary dam structures, while moving obstacles include cable cranes, tower cranes, dam surface construction machinery such as leveling machines and vibratory compactors, and construction personnel. In monitoring these collision targets, the location information of fixed obstacles can be directly updated by the system based on data such as on-site construction progress. However, the location information of moving obstacles requires the selection of an appropriate positioning method for real-time monitoring. Finally, in the safe operation and construction management of cable cranes, positioning monitoring is only a means to understand the dynamics of cable crane operation, and collision detection is only used to determine the safety of cable crane operation; its ultimate goal is to prevent collisions. Therefore, the key to solving the cable crane collision problem lies in conducting collision detection based on real-time positioning data and proposing reasonable anti-collision control measures for cable crane operation. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems by providing a cable crane anti-collision control method that improves positioning accuracy through a combination of positioning techniques. This method employs multiple positioning techniques, including combined positioning, to accurately grasp the real-time location information of machinery and personnel during cable crane construction. It utilizes collision detection methods to assess the real-time location data of the cable crane and potential obstacles, analyzes the safety of cable crane operation, and establishes an anti-collision control mechanism to promptly provide obstacle avoidance adjustment schemes for situations with collision risks. This provides safe cable crane operation guidance for dam construction management personnel.

[0005] The technical solution of this invention is a cable crane anti-collision control method that improves positioning accuracy by using a combined positioning approach, comprising the following steps:

[0006] Step 1: Use collision detection methods to detect conflicts between the cable car and obstacles;

[0007] Step 2: Determine the type of obstacle based on the location coordinates provided by the positioning server;

[0008] Step 3: For fixed obstacles, calculate the braking distance l and the time t required to brake at the current speed of the cable car, and compare them with the cable car warning distance L and warning time T set by the system respectively.

[0009] Step 3.1: If l is not less than L, a distance warning is issued to remind the cable crane operator to brake the cable crane;

[0010] Step 3.2: If t is not less than T, issue a time warning to remind the cable crane operator to stop the cable crane;

[0011] Step 3.3: If l is less than L and t is less than T, then calculate the safe running time for continuing forward according to the current motion state;

[0012] Step 4: For moving obstacles, determine the target to be adjusted according to the cable car anti-collision priority adjustment rules, and take control measures for the target to prevent collisions.

[0013] Preferably, the construction equipment includes a tower crane, a hoist, a hoisting tank, a leveling machine, and a vibratory compactor; the tower crane is equipped with a GPS positioning device, the hoisting tank is equipped with a GPS-UWB combined positioning device, the leveling machine is equipped with a UWB positioning device, and the vibratory compactor is equipped with a UWB positioning device.

[0014] The GPS positioning method uses the DGPS differential global positioning system pseudorange differential, utilizing GPS reference stations on the dam crest slope for positioning differential, achieving an accuracy of decimeter-level precision. The UWB positioning method uses TDOA time difference of arrival positioning technology, receiving pulse signals emitted by the positioning device through multiple UWB positioning base stations, thereby differentially calculating the position of the positioning device, achieving an accuracy of centimeter-level precision. The combined positioning method uses a positioning device that can both receive GPS satellite signals and emit UWB pulses. Installing this combined positioning device on cable cranes and tower cranes allows for seamless positioning and monitoring of the movement of cable cranes and tower cranes.

[0015] If the moving obstacle is the priority adjuster in a potential collision, issue an emergency avoidance instruction to the moving obstacle, causing the construction machinery or personnel to stop or avoid it; if the cable crane is the priority adjuster in a potential collision, adjust it in a timely manner by using the cable crane anti-collision gear adjustment or de-gear judgment method, or by using gear adjustment, de-gear adjustment, or braking.

[0016] Furthermore, the collision detection method specifically includes the following steps:

[0017] 1) Using data conversion and synthesis methods, the positioning data of the positioning equipment is converted and synthesized, and the real-time coordinate information of construction machinery and personnel is stored in the positioning system server;

[0018] 2) Based on the spatial coordinates of the obstacles from the positioning server and the database server, calculate the spatial distance between the cable crane and these obstacles, and compare the spatial distance between the cable crane and the obstacles with the construction safety distance;

[0019] 2.1) If the spatial distance is less than the safe distance, issue a collision warning directly and proceed to step 5);

[0020] 2.2) If the spatial distance is greater than the safe distance, proceed to step 3);

[0021] 3) Identify spatial conflicts and determine potential spatial conflicts based on the direction of movement of the cable car and the direction of movement of other moving obstacles;

[0022] 4) For obstacles that may cause spatial conflicts, calculate the arrival time of the cable car and the obstacle at the intersection point based on the current speed;

[0023] 4.1) If the arrival times at the rendezvous point are the same, it is determined that a spacetime conflict will occur, and step 5) is executed;

[0024] 4.2) If the arrival times at the meeting point are different and there is no risk of collision, proceed to step 6);

[0025] 5) Directly report collision risks to the cable crane operator, provide timely warnings, and remind the operator to take necessary measures;

[0026] 6) Determine if the cable car is running;

[0027] 6.1) If the cable crane is in operation, display a dynamic monitoring screen of the cable crane construction process to the cable crane operator and proceed with step 1);

[0028] 6.2) If the cable machine stops running, then stop the detection.

[0029] Furthermore, the specific steps of the data transformation and synthesis method are as follows:

[0030] (1) The GPS coordinate data of the GPS / UWB combined positioning device is transformed by Gauss-Kruger projection to obtain WGS-84 plane rectangular coordinate data, and then the WGS-84 plane rectangular coordinate data is transformed by Krasovsky ellipsoid to obtain BJ-54 rectangular coordinate data.

[0031] (2) The coordinates of the UWB positioning base station are obtained by engineering surveying, and the relative coordinate data of UWB positioning in the GPS / UWB combined positioning device is obtained by time difference of arrival positioning technology, so that the UWB positioning data is also unified into BJ-54 plane rectangular coordinate data.

[0032] (3) The coordinate data from step (1) and step (2) are denoised and integrated using a particle filter algorithm to obtain high-precision GPS / UWB combined positioning device coordinate data.

[0033] Furthermore, the specific steps for determining whether to increase or decrease the anti-collision gear of the cable car are as follows:

[0034] Step 1: Define the influence range of the cable crane as a cone with the cable crane can as the center, radius r, and height equal to the height of the can;

[0035] Step 2: Calculate the first-arrival adjustment distance L1 and the second-arrival adjustment distance L2 based on the current position of the cable crane canister, the influence range of the cable crane, and the coordinates of potential collision points;

[0036] Step 3: Based on the cable car speed v and the potential collision time interval t, use the formula Calculate the minimum acceleration a1, compare it with the available acceleration gears of the current cable car, and check if there is an acceleration gear with an acceleration greater than a1;

[0037] Step 3.1: If there is a gear with an acceleration greater than a1, inform the cable car operator that an acceleration gear is available;

[0038] Step 3.2: If there is no gear with acceleration greater than a1, proceed to Step 4;

[0039] Step 4: Based on the cable car speed v and the potential collision time interval t, use the formula Calculate the maximum acceleration a2 and compare it with the available deceleration gears of the current cable car to see if there are any deceleration gears with an acceleration less than a2;

[0040] Step 4.1: If there is a gear with an acceleration less than a2, inform the cable car operator that a deceleration gear is available;

[0041] Step 4.2: If there is no gear with an acceleration less than a2, inform the cable car operator that there is no available gear.

[0042] Compared with the prior art, the beneficial effects of the present invention include:

[0043] 1) This invention detects possible collision situations through collision detection methods and anti-collision control methods, and makes timely adjustments by taking anti-collision control measures to ensure the safe and efficient operation of the cable crane during construction, thus forming an effective anti-collision control mechanism for the cable crane;

[0044] 2) This invention combines the characteristics of cable crane construction with a combined positioning technology. The combined positioning has high accuracy, good real-time performance, and unlimited monitoring range. The positioning accuracy reaches the centimeter level, enabling seamless real-time monitoring of the cable crane. It accurately grasps the real-time position information of machinery and personnel during the cable crane construction process and effectively realizes the visualization of the cable crane construction process monitoring. This provides reliable collision detection results and collision prevention safety guidance for cable crane operators and construction safety management personnel, thereby improving the safety and efficiency of cable crane construction. Attached Figure Description

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] Figure 1 This is an overall structural diagram of the cable crane operation monitoring and anti-collision system according to an embodiment of the present invention.

[0047] Figure 2 This is a layout diagram of the GPS / UWB combined positioning device according to an embodiment of the present invention.

[0048] Figure 3 This is a schematic diagram of the location data conversion according to an embodiment of the present invention.

[0049] Figure 4 This is a schematic diagram of location data synthesis according to an embodiment of the present invention.

[0050] Figure 5 This is a flowchart of cable crane collision detection according to an embodiment of the present invention.

[0051] Figure 6 This is a schematic diagram of the cable car collision process according to an embodiment of the present invention.

[0052] Figure 7 This is a schematic diagram of the cable car anti-collision adjustment according to an embodiment of the present invention.

[0053] Figure 8 This is a schematic diagram of the cable car anti-collision reduction adjustment according to an embodiment of the present invention.

[0054] Figure 9 This is a flowchart of the cable crane anti-collision control process according to an embodiment of the present invention. Detailed Implementation

[0055] like Figure 1 As shown in the embodiment, a cable crane operation monitoring and anti-collision system based on GPS / UWB combined positioning was constructed. This system mainly includes two parts: cable crane construction positioning monitoring and dynamic visualization, and cable crane anti-collision. The positioning monitoring and visualization part consists of basic hardware and software. The basic hardware includes a GPS / UWB combined positioning device, a network transmission device, a database server, a display, and a positioning system server. The software is divided into three modules: a positioning data conversion program, a combined positioning data synthesis program, and a construction dynamic visualization program. The cable crane anti-collision part is implemented by a cable crane collision detection method and a cable crane anti-collision control method.

[0056] The GPS / UWB integrated positioning equipment and network transmission equipment in this system include a GPS base station, wireless communication equipment, a UWB positioning base station, a UWB synchronization controller, and connecting optical fibers and positioning devices. The positioning equipment comes in three forms: GPS positioning devices, UWB positioning devices, and GPS / UWB integrated positioning devices. The wireless communication equipment, synchronization controller, and database server are connected to the positioning system server via a local area network. The display is connected to the positioning system server. The UWB positioning base station is connected to the synchronization controller via optical fiber. The database server is a construction information database server, storing dam construction information such as the spatial location of dam structures, formwork, and other fixed obstacles.

[0057] The GPS positioning device can receive GPS satellite signals and transmit the positioning results to the positioning system server in real time through a wireless communication device; the UWB positioning device can emit UWB pulse signals, which can be received by surrounding UWB positioning base stations to obtain its location information; and the GPS / UWB combined positioning device combines the functions of the above two positioning devices, which can both receive GPS satellite signals and emit UWB pulse signals, thereby simultaneously obtaining the GPS positioning data and UWB positioning data of the positioning device.

[0058] The GPS reference station also functions as a GPS positioning device, but its spatial location is known and fixed. During GPS positioning, it is used to perform differential calculations with positioning data from other GPS devices, thereby improving positioning accuracy. The UWB positioning base station serves a similar purpose. During UWB positioning, the pulse signal emitted by a UWB positioning device is received by multiple surrounding UWB positioning base stations. These base stations use TDOA (Time Difference of Arrival) calculations to obtain the accurate location coordinates of the positioning device.

[0059] like Figure 2 As shown, appropriate positioning methods are selected based on the differences in the movement range, movement characteristics, and positioning accuracy requirements of various construction machinery and personnel during cable crane construction. Specifically, GPS positioning monitoring is used for the main and auxiliary towers of the cable crane, the cable crane trolley, and the tower crane; UWB positioning monitoring is used for the leveling machine, vibratory compactor, and construction personnel moving on the cable bed; and combined positioning is used for the cable crane hoisting can and the tower crane hoisting can. The positioning methods for the cable crane and construction equipment are shown in Table 1.

[0060] Table 1. Positioning methods for cable cranes and construction equipment

[0061]

[0062]

[0063] The GPS positioning employs DGPS (Differential Global Positioning System) pseudorange differential positioning, utilizing GPS base stations on the dam crest slope for differential positioning, achieving decimeter-level accuracy. The UWB positioning uses TDOA (Time Difference of Arrival) technology, receiving pulse signals transmitted by the positioning device from multiple UWB positioning base stations to differentially calculate the device's position, achieving centimeter-level accuracy. In this embodiment, the combined positioning utilizes a positioning device capable of both receiving GPS satellite signals and transmitting UWB pulses. Installing this combined positioning device on the cable crane's suspended tank enables seamless positioning and monitoring of the tank's movement.

[0064] The positioning data conversion program is mainly used to convert both GPS and UWB positioning data into a unified BJ-54 rectangular coordinate system, i.e., construction coordinates. The positioning data conversion process is as follows: Figure 3 As shown, GPS positioning data is in WGS-84 geodetic coordinates of the form (B, L, H), where B represents latitude, L represents longitude, and H represents altitude. During the conversion process, it is first converted to WGS-84 plane rectangular coordinates using the Gauss-Kruger projection, and then to BJ-54 rectangular coordinates using the Krasovsky ellipsoid. Simultaneously, since the data obtained by the UWB positioning device is relative coordinates (ΔX, ΔY, ΔZ) with the UWB positioning base station as the reference, where ΔX, ΔY, and ΔZ represent the distances of the positioning device relative to the base station in the X, Y, and Z axes respectively, the construction coordinates of the UWB positioning device can be obtained by using engineering surveying methods to acquire the construction coordinates of the UWB positioning base station. Therefore, this positioning data conversion program can convert both GPS and UWB positioning data into construction coordinates.

[0065] The GPS / UWB combined positioning data synthesis program employs a known particle filter algorithm. This algorithm references the paper "Research on Hybrid Precise and Seamless Positioning Technology of DGPS and UWB" published in Volume 31, Issue 3 of 2012, *Sensors and Microsystems*. It processes the GPS / UWB combined positioning data in real time to obtain high-precision fused positioning data under this combined positioning method. The combined positioning data fusion process is as follows: Figure 4As shown, when the positioning system server fuses GPS and UWB positioning data, due to the difference in refresh rates between the two, or in situations where only one type of positioning can be performed, three types of positioning data will occur: only UWB positioning data, only GPS positioning data, and both UWB and GPS data. Leveraging the advantages of particle filters—their applicability to arbitrary noise distribution and their ability to effectively fuse data from different sensors—this positioning system uses particle filters to process the positioning data received from the central server in real time, thereby ensuring that the positioning accuracy meets monitoring requirements.

[0066] After the above-mentioned conversion and synthesis of positioning data, the real-time location information of construction equipment and personnel during the cable crane construction process is stored in the positioning system server. For example... Figure 1 As shown, the positioning system server uses a cable crane construction dynamic visualization program to display and output this location information so that cable crane operators and construction safety managers can intuitively understand the details of the construction process. The cable crane construction visualization program utilizes 3D modeling technology to model entities such as the dam body and construction machinery during cable crane construction, uses the Unity3D development environment to implement virtual simulation of cable crane construction, and uses a driver program written in C# that takes location data as input to ensure that the positions of construction machinery and personnel in the virtual construction scene change in real time according to the real-time positioning data.

[0067] like Figure 5 The collision avoidance system first employs a cable car collision detection method to assess the cable car's movement in real time, thereby promptly identifying and adjusting for potential collision risks. This collision detection method is applicable not only to cable cars and fixed obstacles but also to situations involving cable cars and moving obstacles. Figure 6 As shown, since a collision is a situation where objects overlap simultaneously in time and space, the specific steps of the cable car collision detection method are as follows:

[0068] Step 1: Using data conversion and synthesis methods, the positioning data of the positioning equipment is converted and synthesized, and the real-time coordinate information of construction machinery and personnel is stored in the positioning system server;

[0069] Step 2: Based on the spatial coordinates of the obstacles from the positioning server and the database server, calculate the spatial distance between the cable crane and these obstacles, and compare the spatial distance between the cable crane and the obstacles with the construction safety distance;

[0070] Step 2.1: If the spatial distance is less than the safe distance, issue a collision warning directly and proceed to step 5;

[0071] Step 2.2: If the spatial distance is greater than the safe distance, proceed to step 3;

[0072] Step 3: Identify spatial conflicts by determining potential spatial conflicts based on the direction of the cable car's movement and the movement directions of other moving obstacles.

[0073] Step 4: For obstacles with potential spatial conflicts, calculate the arrival time of the cable car and the obstacle at the intersection point based on the current speed;

[0074] Step 4.1: If the arrival times at the rendezvous point are the same, it is determined that a spacetime conflict will occur, and step 5 is executed;

[0075] Step 4.2: If the arrival times at the rendezvous point are different and there is no risk of collision, proceed to step 6;

[0076] Step 5: Directly report the collision risk to the cable crane operator, provide timely warnings, and remind the operator to take necessary measures;

[0077] Step 6: Determine if the cable car is running;

[0078] Step 6.1: If the cable crane is running, display the dynamic monitoring screen of the cable crane construction process to the cable crane operator and proceed to step 1;

[0079] Step 6.2: If the cable car stops running, stop the detection.

[0080] In the above-mentioned collision detection method, on the one hand, the position information of each moving machine and personnel is obtained by using real-time positioning data and the corresponding running speed is calculated. On the other hand, the position information of fixed obstacles during the cableway construction process is obtained based on the construction information, so as to carry out collision detection based on the position relationship and speed information between the cableway and potential obstacles.

[0081] The cable crane anti-collision control method, based on the collision detection results, can make timely adjustments to situations where collisions may occur. During the adjustment process, the type of potential obstacle is first determined: fixed obstacles or moving obstacles. For fixed obstacles, a reliable safety warning mechanism is established based on the cable crane's current speed and its distance from the fixed obstacle. For moving obstacles, the priority relationship between the two types of adjustments is first determined. If other construction machinery and personnel are prioritized for adjustment, the cable crane's movement does not need to be adjusted. However, if the cable crane is the priority target for adjustment, the cable crane's gear is adjusted to ensure the hoisting can pass before (or after) the moving obstacle reaches the predicted collision point, thereby avoiding a collision. The preferred adjustment rules for cable crane anti-collision are shown in Table 2.

[0082] Table 2 Cable crane anti-collision priority adjustment rules

[0083]

[0084] according to Figure 6In cases where the cable car and a moving obstacle overlap in both time and space, and the cable car is the priority adjustment target in the adjustment rules, the following can be applied: Figure 7 , Figure 8 The control methods include shifting gears, shifting gears, or braking. During adjustment, the position, speed, and direction of the moving obstacle are first acquired. The arrival time interval t of the moving obstacle is calculated based on the collision detection's predicted intersection point. This information forms the basis for analyzing the cable car's adjustment method. The main part of the cable car prone to collision with these moving obstacles during operation is the hanging container. Considering the impact of the container's swaying, a circle with radius r is added to the collision detection and anti-collision control systems as the cable car's influence range.

[0085] Figure 7 This diagram illustrates the adjustment of the cable car's anti-collision gear. Since the moving obstacle will reach the intersection point at time t, the cable car's influence range should at least exactly pass through this intersection point at time t, i.e., reach the position shown in the diagram. This distance is called the initial adjustment distance L1, calculated from the cable car's current speed v according to the formula: Using this formula, the acceleration a1 required to reach the first adjustment distance L1 can be calculated. This acceleration a1 is then compared with the adjustable acceleration gears of the current cable car to see if there is an acceleration gear that can at least reach the required acceleration a1. If so, an adjustment to a higher gear is prompted to avoid a collision.

[0086] Figure 8 This is a schematic diagram of the cable crane's anti-collision reduction gear. The calculation principle is similar to the gear-up adjustment method described above, except that the adjustment distance L2 is used as the calculation standard, and the formula is: Similarly, the acceleration a2 required to reach the adjustment distance L2 can be obtained. This acceleration a2 is then compared with the currently adjustable deceleration gear to see if there is a deceleration gear that can at least reach the required acceleration a2. If so, a prompt is made to downshift; otherwise, braking is applied in time to avoid a collision.

[0087] like Figure 9As shown, the cable crane anti-collision control method mainly makes the following adjustments for possible collision situations: Based on the location information provided by positioning monitoring and the construction database, the type of obstacle is determined: fixed obstacle or moving obstacle. For fixed obstacles, the current speed of the cable crane is first calculated, and then the braking distance *l* and braking time *t* required at that speed are calculated. These are compared with the system-set cable crane warning distance *L* and warning time *T*. If *l* is not less than *L*, a distance warning is issued; if *t* is not less than *T*, a time warning is issued; if both are less than *T*, the safe operating time for continuing in the current motion state is calculated. For moving obstacles, a priority adjustment rule base is established based on the aforementioned priority adjustment principle. If the moving obstacle is the priority adjustment target in the collision, the cable crane's motion state does not need to be adjusted; only an emergency avoidance instruction is issued to the moving obstacle, causing the construction machinery or personnel to stop or avoid it. If the cable crane is the priority adjustment target in the collision, timely adjustment is performed according to the above-mentioned cable crane anti-collision gear adjustment methods or cable crane braking.

Claims

1. A cable crane anti-collision control method that improves positioning accuracy by employing a combined positioning approach, characterized in that, The collision targets of the cable crane include construction equipment and construction personnel. Differentiated positioning configurations are used for construction equipment and construction personnel: large construction equipment uses GPS positioning, construction equipment and personnel in a small area on the warehouse surface use UWB positioning, and the hoisting tank uses a combination of GPS and UWB positioning. The cable crane anti-collision control method includes the following steps: Step 1: Use collision detection methods to detect conflicts between the cable car and obstacles; Step 2: Determine the type of obstacle based on the location coordinates provided by the positioning server; Step 3: For fixed obstacles, calculate the braking distance l and the time t required to brake at the current speed of the cable car, and compare them with the cable car warning distance L and warning time T set by the system respectively. Step 3.1: If l is not less than L, a distance warning is issued to remind the cable crane operator to brake the cable crane; Step 3.2: If t is not less than T, issue a time warning to remind the cable crane operator to stop the cable crane; Step 3.3: If l is less than L and t is less than T, then calculate the safe running time for continuing forward according to the current motion state; Step 4: For cases involving moving obstacles, determine the adjustment target based on the cable car anti-collision priority adjustment rules; The priority adjustment rules for cable crane anti-collision are shown in Table 2. Table 2 Cable crane anti-collision priority adjustment rules If the moving obstacle is the priority adjuster in a potential collision, issue an emergency avoidance instruction to the moving obstacle, causing the construction machinery or personnel to stop or avoid it; if the cable crane is the priority adjuster in a potential collision, adjust it in a timely manner by using the cable crane anti-collision gear adjustment or de-gear judgment method, or by using gear adjustment, de-gear adjustment, or braking.

2. The cable crane anti-collision control method according to claim 1, characterized in that, The construction equipment includes tower cranes, hoists, hoisting tanks, leveling machines, and vibratory compactors; the tower cranes are equipped with GPS positioning devices, the hoisting tanks are equipped with GPS-UWB combined positioning devices, the leveling machines are equipped with UWB positioning devices, and the vibratory compactors are equipped with UWB positioning devices. The positioning of cable cranes, construction equipment, and construction personnel is shown in Table 1. Table 1. Positioning methods for cable cranes and construction equipment The GPS positioning method uses the DGPS differential global positioning system pseudorange differential, and utilizes the GPS reference station on the dam crest slope for positioning differential, with an accuracy of decimeter level; UWB positioning uses the TDOA (Time Difference of Arrival) positioning method, which receives pulse signals emitted by the positioning device from multiple UWB positioning base stations, and then calculates the position of the positioning device differentially, with an accuracy of centimeter level. The combined positioning system employs a positioning device that can receive GPS satellite signals and transmit UWB pulses. By installing this combined positioning device on cable cranes and tower cranes, seamless positioning and monitoring of the movement of cable cranes and cranes can be achieved.

3. The cable crane anti-collision control method according to claim 2, characterized in that, The collision detection method specifically includes the following steps: 1) Using data conversion and synthesis methods, the positioning data of the positioning equipment is converted and synthesized, and the real-time coordinate information of construction machinery and personnel is stored in the positioning system server; 2) Based on the spatial coordinates of the obstacles from the positioning server and the database server, calculate the spatial distance between the cable crane and these obstacles, and compare the spatial distance between the cable crane and the obstacles with the construction safety distance; 2.1) If the spatial distance is less than the safe distance, issue a collision warning directly and proceed to step 5). 2.2) If the spatial distance is greater than the safe distance, proceed to step 3). 3) Identify spatial conflicts and determine potential spatial conflicts based on the direction of movement of the cable car and the direction of movement of other moving obstacles; 4) For obstacles that may cause spatial conflicts, calculate the arrival time of the cable car and the obstacle at the intersection point based on the current speed; 4.1) If the arrival times at the rendezvous point are the same, it is determined that a spacetime conflict will occur, and step 5) is executed. 4.2) If the arrival times at the meeting point are different and there is no risk of collision, proceed to step 6). 5) Directly report collision risks to the cable crane operator, provide timely warnings, and remind the operator to take necessary measures; 6) Determine if the cable car is running; 6.1) If the cable crane is in operation, display a dynamic monitoring screen of the cable crane construction process to the cable crane operator and execute step 1). 6.2) If the cable machine stops running, then stop the detection.

4. The cable car anti-collision control method according to claim 3, characterized in that, The specific steps of the data transformation and synthesis methods are as follows: (1) The GPS coordinate data of the GPS / UWB combined positioning device is transformed by Gauss-Kruger projection to obtain WGS-84 plane rectangular coordinate data, and then the WGS-84 plane rectangular coordinate data is transformed by Krasovsky ellipsoid to obtain BJ-54 rectangular coordinate data. (2) Use engineering surveying methods to obtain the coordinates of UWB positioning base stations, and use time difference of arrival positioning technology to obtain the relative coordinate data of UWB positioning in GPS / UWB combined positioning equipment, so as to unify the UWB positioning data into BJ-54 plane rectangular coordinate data. (3) The coordinate data in step (1) and step (2) are denoised and integrated using the particle filter algorithm to obtain high-precision GPS / UWB combined positioning device coordinate data.

5. The cable crane anti-collision control method according to claim 4, characterized in that, The specific steps of the cable crane anti-collision gear increase or decrease judgment method are as follows: Step 1: Define the influence range of the cable crane as a cone with the cable crane can as the center, radius r, and height equal to the height of the can; Step 2: Calculate the first-arrival adjustment distance L1 and the second-arrival adjustment distance L2 based on the current position of the cable crane canister, the influence range of the cable crane, and the coordinates of potential collision points; Step 3: Based on the cable car speed v and the potential collision time interval t, use the formula Calculate the minimum acceleration a1, compare it with the available acceleration gears of the current cable car, and check if there are any acceleration gears with an acceleration greater than a1; Step 3.1: If there is a gear with an acceleration greater than a1, inform the cable car operator that an acceleration gear is available; Step 3.2: If there is no gear with acceleration greater than a1, proceed to Step 4; Step 4: Based on the cable car speed v and the potential collision time interval t, use the formula Calculate the maximum acceleration a2 and compare it with the available deceleration gears of the current cable car to see if there are any deceleration gears with an acceleration less than a2; Step 4.1: If there is a gear with an acceleration less than a2, inform the cable car operator that a deceleration gear is available; Step 4.2: If there is no gear with an acceleration less than a2, inform the cable car operator that there is no available gear.

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