Automatic obstacle avoidance system of tower crane

Abstract

The invention relates to the technical field of tower crane obstacle avoidance, and particularly discloses a tower crane automatic obstacle avoidance system which comprises a positioning module, an obstacle monitoring module, a PLC control module, an electric control and brake module and a feedback module. The positioning module monitors the movement track and angle change of the tower crane boom in real time; the obstacle monitoring module monitors the surrounding environment of the tower crane in real time through a laser radar and an ultrasonic sensor; the PLC control module is used for receiving real-time data and analyzing the current position, angle and surrounding environment of the tower crane; the electric control and brake module is used for monitoring real-time data from the positioning module and the obstacle monitoring module and rapidly cutting off the power of the rotary motor when the tower crane enters a dangerous area; and the feedback module allows an operator to carry out manual intervention in an emergency through a foot switch function. According to the invention, potential safety hazards caused by human errors are reduced, and the safety of the tower crane in operation in a complex environment is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of tower crane obstacle avoidance, and more specifically, to an automatic obstacle avoidance system for a tower crane. Background Art

[0002] When lifting heavy objects, the crane arm often needs to operate in a small and complex working environment. The rotation radius and working range of the crane arm may conflict with other surrounding equipment, cranes or buildings, thus causing collision risks. Especially in high-density construction sites, due to the insufficient distance between cranes, there may be safety hazards such as the crane arm accidentally approaching or colliding with other cranes. Traditional protective measures mainly rely on the experience and alertness of the crane driver and the command of the signalman, but this does not always completely avoid collisions, especially when the field of vision is limited or the operation pressure is high. In the existing public patent 1 (a remote tower crane intelligent centralized control system based on 5G communication, CN118877746A), a remote tower crane intelligent centralized control system applied to the field of construction is provided, which is composed of several tower cranes, a centralized control platform and a ground equipment system. Each tower crane is equipped with a tower crane side equipment system including a variety of sensors, cameras, etc. The ground equipment system communicates with the tower crane side equipment system through the 5G network. The centralized control platform is equipped with a collision monitoring system and related analysis modules, which can perform vertical and plane rotation collision analysis based on sensor data to ensure the safety of multi-tower crane construction. In the existing public patent 2 (a construction tower crane group hoisting operation anti-collision warning device, CN110342402A), a tower crane group hoisting operation anti-collision warning device is provided, including a distance sensor group, a main control module, an input control module, a communication module, a ground control terminal, a relay switch and a warning reminder module. Through the coordinated work of various components, the distance measurement is used to determine whether the crane working range overlaps. When there is a possibility of collision, the trajectory is detected and the operation cabin and the ground control terminal are warned to avoid tower crane collision and ensure operation safety. The current technical level of tower crane operation safety needs to be further improved, and intelligent and automated control systems should be introduced to more accurately monitor dangerous areas during tower crane operations, respond in real time and effectively avoid potential obstacles, and avoid safety hazards caused by human errors or mechanical failures. Summary of the invention

[0003] In order to overcome the above-mentioned defects of the prior art, the present invention provides an automatic obstacle avoidance system for a tower crane, which utilizes a high-precision differential GPS receiver to accurately monitor the motion trajectory and angle changes of the tower crane's lifting arm, combines the laser radar and ultrasonic sensor of the obstacle monitoring module to realize monitoring of the surrounding environment, analyzes real-time data based on a safe distance algorithm, and quickly sends out a control signal in case of danger, promptly cuts off the power of the slewing motor, and effectively avoids obstacles, so as to solve the problems raised in the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] An automatic obstacle avoidance system for a tower crane comprises a positioning module, an obstacle monitoring module, a PLC control module, an electric control and braking module and a feedback module; the positioning module monitors the motion trajectory and angle change of the tower crane arm in real time through a high-precision differential GPS (DGPS) receiver, combined with satellite signals and ground station differential correction signals; the obstacle monitoring module monitors the surrounding environment of the tower crane in real time through a laser radar and an ultrasonic sensor; the PLC control module receives real-time data from the positioning module and the obstacle monitoring module, and analyzes the current position, angle and surrounding environment of the tower crane in real time; the electric control and braking module quickly cuts off the power of the slewing motor when the tower crane enters a dangerous area by monitoring the real-time data from the positioning module and the obstacle monitoring module; the feedback module allows an operator to manually intervene in an emergency through a foot switch function;

[0006] The PLC control module has an embedded logic control algorithm. When the crane arm approaches the preset danger zone through the data feedback of the positioning module and the obstacle detection module, the PLC control module makes a judgment based on the safety distance algorithm. The calculation formula is: Among them, D cur is the current distance between the tower crane arm and the obstacle, (X arm ,Y arm ) is the current coordinate of the tower crane boom, indicating the position of the tower crane boom, (X obs ,Y obs ) is the coordinate position of the obstacle, and the current distance D between the tower crane boom and the obstacle is calculated. cur From the preset safety distance D safe By comparison, the safety distance D safe It is the minimum distance that must be maintained between the tower crane boom and obstacles.

[0007] As a further solution of the present invention, the positioning module uses a high-precision differential GPS (DGPS) receiver, combined with satellite signals and ground station differential correction signals, to monitor the motion trajectory and angle changes of the tower crane's lifting arm in real time, including the following specific contents: In order to achieve high-precision positioning function, the positioning module adopts a high-precision differential GPS receiver. The differential GPS can effectively reduce interference factors such as multipath effect, delay error and spatial error by receiving multi-frequency signals from satellites and combining differential correction signals from local ground stations. Compared with traditional GPS, differential GPS can reduce errors caused by factors such as atmosphere and terrain, provide positioning accuracy accurate to centimeters, and ensure that the tower crane can accurately identify its current position and angle in complex environments. The hardware configuration of the differential GPS receiver includes a high-precision receiving antenna and a high-frequency processing unit. The receiving antenna can receive satellite signals, and the high-frequency processing unit is responsible for quickly processing the received satellite signals, accurately setting the rotation angle of the tower crane, and calculating the position information of the tower crane in real time. Through this configuration, the positioning module can accurately monitor the movement trajectory and angle change of the tower crane when the boom rotates, ensuring that the boom always operates within a safe range. The differential GPS receiver is installed at a high position of the tower crane, such as the top of the tower crane or the center of the boom. Installing it at this position can reduce signal obstruction and ensure that a stable signal from the satellite is received.

[0008] The positioning module also has a warning voice providing function. When the tower crane's boom rotates to the left to 180 degrees or to the right to 140 degrees, the positioning module issues a warning voice prompt to inform the operator that the preset warning position has been reached.

[0009] The rotation angle accuracy of the positioning module is within ±5°. In addition to the rotation angle accuracy, the horizontal position of the tower crane boom also needs to be accurately positioned. The horizontal position error of the tower crane boom cannot exceed 10 cm. In order to achieve this requirement, the positioning module adopts real-time dynamic positioning technology and provides real-time correction information through the reference station. The calculation formula of the real-time dynamic positioning technology is: Among them, ρ f is the actual distance between the tower crane and the reference station, (X f -X b ) 2 +(Y f -Y b ) 2 +(Z f -Z b ) 2 is the plane distance between the tower crane and the reference station in three-dimensional space, X f ,Y f ,Z fis the three-dimensional coordinate of the tower crane, X b ,Y b ,Z b is the three-dimensional coordinate of the reference station, ΔL is the differential correction term, which is the correction value sent by the reference station to the tower crane. Through the differential calculation between the reference station and the tower crane, the measurement error can be eliminated or reduced to improve the positioning accuracy. The differential correction term ΔL can be expressed as: ΔL = ΔL f -ΔL b , where ΔL f is the error term of the tower crane, that is, the error between the distance measured by the tower crane and the actual distance, ΔL b is the error term of the reference station, that is, the error between the distance measured by the reference station and the actual distance.

[0010] As a further solution of the present invention, the obstacle monitoring module monitors the surrounding environment of the tower crane in real time through laser radar and ultrasonic sensors, including the following specific contents: the obstacle monitoring module monitors the surrounding environment of the tower crane in real time through laser radar and ultrasonic sensors. In order to ensure that the tower crane can scan the surrounding environment 360° in all directions, the laser radar is installed at the top of the tower crane or the front end of the boom, so that the laser radar can fully cover the space around the tower crane, especially can effectively detect obstacles far away from the tower crane. The detection range of the ultrasonic sensor is relatively short, between a few meters and more than ten meters, and is used for close-range monitoring around the tower crane boom. The ultrasonic sensor is installed at the bottom of the tower crane and the rotating joint of the boom, and can monitor the blind spots around the tower crane boom in real time, ensuring that close-range obstacles are discovered in time during the rotation of the boom.

[0011] As a further solution of the present invention, the PLC control module receives real-time data from the positioning module and the obstacle monitoring module to analyze the current position, angle and surrounding environment of the tower crane in real time, including the following specific contents: the PLC control module receives real-time data from the positioning module and the obstacle detection module, the GSP positioning module provides the current position and angle information of the tower crane, and the obstacle monitoring module provides real-time scanning data of the surrounding environment of the tower crane. The PLC control module analyzes the real-time data. If the movement trajectory of the tower crane conflicts with an obstacle, the PLC control module will immediately send a control signal to instruct the electronic control and brake module to cut off the tower crane's rotation power or start emergency braking to prevent the tower crane's boom from entering a dangerous area. The response time of the PLC control module is between 10 milliseconds and 100 milliseconds.

[0012] The safety logic of the PLC control module is the key to ensure the safe operation of the tower crane in a complex operating environment. The logic control algorithm is embedded in it. The logic control algorithm means that when the tower crane's boom approaches the preset danger zone through the data feedback of the positioning module and the obstacle detection module, the PLC control module will make a judgment based on the safety distance algorithm and calculate the current distance D between the tower crane's boom and the obstacle. cur From the preset safety distance D safe By comparison, the safety distance D safe It is the minimum distance that must be maintained between the tower crane boom and obstacles.

[0013] If the boom is rotated to 190 degrees to the left or 150 degrees to the right, and D cur <D safe , the PLC control system will automatically identify this situation and trigger the safety response mechanism. At this time, the positioning module will transmit the position information to the PLC control module, issue a restriction instruction, and warn the tower crane to enter the dangerous area. After receiving this instruction, the PLC control module will immediately issue a series of control commands to prevent collision. First, the PLC control module will issue an instruction to the electric control box of the tower crane to cut off the power supply of the tower crane's slewing motor, stop the slewing power, and ensure that the boom will no longer move to the dangerous area. Then, the PLC control module will instruct the corresponding left-hand or right-hand main AC contactor to disconnect, ensuring that the power supply of the slewing system is completely interrupted, thereby preventing the tower crane's boom from continuing to rotate. At the same time, the PLC control module will also issue a slewing brake action instruction to the slewing brake of the tower crane to start the braking mechanism. The slewing brake will continue to jog the brake and apply braking force until the boom stops completely. Through this series of linkage control measures, the tower crane can stop quickly and avoid entering the dangerous area, thereby effectively avoiding the risk of collision and ensuring the safety of the work site.

[0014] As a further solution of the present invention, the electric control and braking module quickly cuts off the power of the slewing motor when the tower crane enters the dangerous area by monitoring the real-time data from the positioning module and the obstacle monitoring module, including the following specific contents: the electric control and braking module timely cuts off the power of the slewing motor when danger occurs to prevent the tower crane boom from continuing to rotate. The electric control and braking module monitors the real-time data from the positioning module and the obstacle monitoring module, and once it detects that the tower crane boom is about to enter the dangerous area, the electric control system will respond quickly. When controlling the slewing motor, the electric control and braking module realizes power cut-off by controlling the AC contactor, which is a switching device between the electric control and braking module and the motor, which can quickly disconnect the power supply to ensure that the current supply of the slewing motor is immediately interrupted. In order to ensure the rapid response of this process, the power of the slewing motor needs to match the maximum load capacity of the tower crane, that is, the slewing motor should have sufficient power and can generate a large torque in an instant to ensure that the slewing system of the tower crane can respond quickly and shut down.

[0015] The electric control and braking module includes a brake. Since the electromagnetic brake has the advantages of fast response speed and is suitable for quickly cutting off power, the tower crane adopts an electromagnetic brake, which uses the magnetic force generated by the current to control the brake. The PLC control module activates the brake by issuing an inching brake command. The working mode of the brake is inching brake, that is, each braking action lasts for a very short time and brakes through electric pulses. In order to ensure the reliability and effectiveness of the brake, after the PLC control module sends an emergency stop signal, the brake can apply sufficient braking force in a very short time until the boom stops completely and remains in a safe position.

[0016] As a further solution of the present invention, the feedback module allows the operator to manually intervene in an emergency through a foot switch function, including the following specific contents: in an emergency, the automatic obstacle avoidance system of the tower crane has the function of allowing the operator to manually intervene, and a foot switch function is provided in the feedback module as a key interface for manual intervention. When the boom of the tower crane enters a stopped state due to reaching a preset dangerous position or being triggered by the automatic obstacle avoidance system, the operator can use the foot switch to rotate in the opposite direction or release the restriction. The foot switch controls the PLC to instruct the electronic control and brake module, start the reverse rotation of the slewing motor, or release the limit control of the boom, allowing the tower crane boom to safely return to the predetermined area.

[0017] The technical effects and advantages of the automatic obstacle avoidance system for a tower crane of the present invention are as follows: the positioning module of the present invention utilizes a high-precision differential GPS receiver to accurately monitor the movement trajectory and angle changes of the tower crane's lifting arm, has high positioning accuracy and can provide early warning, and is combined with the laser radar and ultrasonic sensor of the obstacle monitoring module to realize monitoring of the surrounding environment. The PLC control module analyzes real-time data based on a safe distance algorithm and quickly sends out a control signal when danger occurs. The electric control and braking module can cut off the power of the rotary motor in time, and an electromagnetic brake is used to ensure fast and effective braking. The foot switch function of the feedback module allows the operator to manually intervene in an emergency, which effectively solves the problems in the prior art of relying on manual experience, prone to errors, limited field of view, and difficulty in avoiding collisions when the operating pressure is high, greatly improving the safety level of tower crane operations, reducing safety hazards caused by human errors or mechanical failures, and ensuring the safety of tower crane operations in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a schematic structural diagram of an automatic obstacle avoidance system for a tower crane.

[0019] Figure 2 This is a schematic diagram of a remote tower crane intelligent centralized control system based on 5G communication in the prior art.

[0020] Figure 3 The present invention is a structural schematic diagram of a collision prevention warning device for hoisting operations of a group of tower cranes in construction in the prior art.

[0021] Figure 4 A schematic diagram of an operator using a foot switch in a feedback module of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1

[0024] See also Figure 1As shown in the structural schematic diagram, an embodiment of the present invention provides an automatic obstacle avoidance system for a tower crane, which includes a positioning module, an obstacle monitoring module, a PLC control module, an electric control and braking module, and a feedback module; the positioning module uses a high-precision differential GPS (DGPS) receiver, combined with satellite signals and ground station differential correction signals, to monitor the motion trajectory and angle changes of the tower crane's lifting arm in real time; the obstacle monitoring module uses a laser radar and an ultrasonic sensor to monitor the surrounding environment of the tower crane in real time; the PLC control module receives real-time data from the positioning module and the obstacle monitoring module, and analyzes the current position, angle and surrounding environment of the tower crane in real time; the electric control and braking module monitors the real-time data from the positioning module and the obstacle monitoring module, and quickly cuts off the power of the slewing motor when the tower crane enters a dangerous area; the feedback module allows the operator to manually intervene in an emergency through the foot switch function.

[0025] In this embodiment, see Figure 2 The schematic diagram is a remote tower crane intelligent centralized control system provided in the prior art for use in the field of construction. It consists of several tower cranes, a centralized control platform and a ground equipment system. Each tower crane is equipped with a tower crane side equipment system including a variety of sensors, cameras, etc. The ground equipment system communicates with the tower crane side equipment system through a 5G network. The centralized control platform is equipped with a collision monitoring system and related analysis modules, which can perform vertical and horizontal rotation collision analysis based on sensor data to ensure the safety of multi-tower crane construction. Figure 3 The structural diagram shown is a tower crane group hoisting operation anti-collision warning device provided in the prior art, including a distance sensor group, a main control module, an input control module, a communication module, a ground control terminal, a relay switch and a warning reminder module. Through the coordinated work of various components, the distance measurement is used to determine whether the crane working range overlaps. When there is a possibility of collision, the trajectory is detected and the operating cabin and the ground control terminal are warned to avoid tower crane collision and ensure operation safety. The current tower crane operation safety technology level urgently needs to be further improved, and an intelligent and automated control system should be introduced to more accurately monitor the dangerous areas during the tower crane operation process, respond in real time and effectively avoid potential obstacles, and avoid safety hazards caused by human errors or mechanical failures.

[0026] Furthermore, the positioning module monitors the motion trajectory and angle change of the tower crane boom in real time through a high-precision differential GPS (DGPS) receiver, combined with satellite signals and ground station differential correction signals, including: In order to achieve high-precision positioning function, the positioning module adopts a high-precision differential GPS receiver, and the differential GPS can effectively reduce interference factors such as multipath effect, delay error and spatial error by receiving multi-frequency signals from satellites and combining differential correction signals from local ground stations. Compared with traditional GPS, differential GPS can reduce errors caused by factors such as atmosphere and terrain, provide positioning accuracy accurate to centimeters, and ensure that the tower crane can accurately identify its current position and angle in complex environments. The hardware configuration of the differential GPS receiver includes a high-precision receiving antenna and a high-frequency processing unit, the receiving antenna can receive satellite signals, and the high-frequency processing unit is responsible for quickly processing the received satellite signals, accurately setting the rotation angle of the tower crane, and calculating the position information of the tower crane in real time. Through this configuration, the positioning module can accurately monitor its motion trajectory and angle change when the tower crane rotates its boom, ensuring that the boom always operates within a safe range. The differential GPS receiver is installed at a high position of the tower crane, such as the top of the tower crane or the center of the boom. Installing it at the above position can reduce signal shielding and ensure the reception of stable signals from the satellite.

[0027] The positioning module also has a warning voice providing function. When the tower crane's boom rotates to the left to 180 degrees or to the right to 140 degrees, the positioning module issues a warning voice prompt to inform the operator that the preset warning position has been reached.

[0028] The rotation angle accuracy of the positioning module is within ±5°. In addition to the rotation angle accuracy, the horizontal position of the tower crane boom also needs to be accurately positioned. The horizontal position error of the tower crane boom cannot exceed 10 cm. In order to achieve this requirement, the positioning module adopts real-time dynamic positioning technology and provides real-time correction information through the reference station. The calculation formula of the real-time dynamic positioning technology is: Among them, ρ f is the actual distance between the tower crane and the reference station, (X f -X b ) 2 +(Y f -Y b ) 2 +(Z f -Z b ) 2 is the plane distance between the tower crane and the reference station in three-dimensional space, X f ,Y f ,Z f is the three-dimensional coordinate of the tower crane, Xb ,Y b ,Z b is the three-dimensional coordinate of the reference station, ΔL is the differential correction term, which is the correction value sent by the reference station to the tower crane. Through the differential calculation between the reference station and the tower crane, the measurement error can be eliminated or reduced to improve the positioning accuracy. The differential correction term ΔL can be expressed as: ΔL = ΔL f -ΔL b , where ΔL f is the error term of the tower crane, that is, the error between the distance measured by the tower crane and the actual distance, ΔL b is the error term of the reference station, that is, the error between the distance measured by the reference station and the actual distance.

[0029] Furthermore, the obstacle monitoring module monitors the surrounding environment of the tower crane in real time through laser radar and ultrasonic sensors, including: the obstacle monitoring module monitors the surrounding environment of the tower crane in real time through laser radar and ultrasonic sensors. In order to ensure that the tower crane can scan the surrounding environment 360° in all directions, the laser radar is installed at the top of the tower crane or the front end of the boom, so that the laser radar can fully cover the space around the tower crane, especially can effectively detect obstacles far away from the tower crane. The detection range of the ultrasonic sensor is relatively short, between a few meters and more than ten meters, and is used for close-range monitoring around the tower crane boom. The ultrasonic sensor is installed at the bottom of the tower crane and the rotating joint of the boom, and can monitor the blind spots around the tower crane boom in real time to ensure that close-range obstacles are discovered in time during the rotation of the boom.

[0030] Furthermore, the PLC control module receives real-time data from the positioning module and the obstacle monitoring module to analyze the current position, angle and surrounding environment of the tower crane in real time, including: the PLC control module receives real-time data from the positioning module and the obstacle detection module, the GSP positioning module provides the current position and angle information of the tower crane, and the obstacle monitoring module provides real-time scanning data of the surrounding environment of the tower crane. The PLC control module analyzes the real-time data. If the movement trajectory of the tower crane conflicts with an obstacle, the PLC control module will immediately send a control signal to instruct the electronic control and brake module to cut off the tower crane's rotation power or start emergency braking to prevent the tower crane's boom from entering a dangerous area. The response time of the PLC control module is between 10 milliseconds and 100 milliseconds.

[0031] The safety logic of the PLC control module is the key to ensure the safe operation of the tower crane in a complex working environment, and has an embedded logic control algorithm. The logic control algorithm means that when the tower crane's boom approaches the preset danger zone through data feedback from the positioning module and the obstacle detection module, the PLC control module will make a judgment based on the safety distance algorithm. The calculation formula of the safety distance algorithm is: Among them, D cur is the current distance between the tower crane arm and the obstacle, (X arm ,Y arm ) is the current coordinate of the tower crane boom, indicating the position of the tower crane boom, (X obs ,Y obs ) is the coordinate position of the obstacle, and the current distance D between the tower crane boom and the obstacle is calculated. cur From the preset safety distance D safe By comparison, the safety distance D safe It is the minimum distance that must be maintained between the tower crane boom and the obstacle. In this embodiment, 4 meters is used as the standard.

[0032] If the boom is rotated to 190 degrees to the left or 150 degrees to the right, and D cur <D safe , the PLC control system will automatically identify this situation and trigger the safety response mechanism. At this time, the positioning module will transmit the position information to the PLC control module, issue a restriction instruction, and warn the tower crane to enter the dangerous area. After receiving this instruction, the PLC control module will immediately issue a series of control commands to prevent collision. First, the PLC control module will issue an instruction to the electric control box of the tower crane to cut off the power supply of the tower crane's slewing motor, stop the slewing power, and ensure that the boom will no longer move to the dangerous area. Then, the PLC control module will instruct the corresponding left-hand or right-hand main AC contactor to disconnect, ensuring that the power supply of the slewing system is completely interrupted, thereby preventing the tower crane's boom from continuing to rotate. At the same time, the PLC control module will also issue a slewing brake action instruction to the slewing brake of the tower crane to start the braking mechanism. The slewing brake will continue to jog the brake and apply braking force until the boom stops completely. Through this series of linkage control measures, the tower crane can stop quickly and avoid entering the dangerous area, thereby effectively avoiding the risk of collision and ensuring the safety of the work site.

[0033] Furthermore, the electric control and braking module monitors the real-time data from the positioning module and the obstacle monitoring module, and quickly cuts off the power of the slewing motor when the tower crane enters the dangerous area, including: the electric control and braking module timely cuts off the power of the slewing motor when danger occurs to prevent the tower crane boom from continuing to rotate. The electric control and braking module monitors the real-time data from the positioning module and the obstacle monitoring module, and once it detects that the tower crane boom is about to enter the dangerous area, the electric control system will respond quickly. When controlling the slewing motor, the electric control and braking module realizes power cut-off by controlling the AC contactor, which is a switching device between the electric control and braking module and the motor, which can quickly disconnect the power supply to ensure that the current supply of the slewing motor is immediately interrupted. In order to ensure the rapid response of this process, the power of the slewing motor needs to match the maximum load capacity of the tower crane, that is, the slewing motor should have sufficient power and be able to generate a large torque in an instant to ensure that the slewing system of the tower crane can respond quickly and shut down.

[0034] The electric control and braking module includes a brake. Since the electromagnetic brake has the advantages of fast response speed and is suitable for quickly cutting off power, the tower crane adopts an electromagnetic brake, which uses the magnetic force generated by the current to control the brake. The PLC control module activates the brake by issuing an inching brake command. The working mode of the brake is inching brake, that is, each braking action lasts for a very short time and brakes through electric pulses. In order to ensure the reliability and effectiveness of the brake, after the PLC control module sends an emergency stop signal, the brake can apply sufficient braking force in a very short time until the boom stops completely and remains in a safe position.

[0035] Further, see Figure 4 As shown in the schematic diagram, the feedback module allows the operator to manually intervene in an emergency through the foot switch function. In an emergency, the tower crane automatic obstacle avoidance system has the function of allowing the operator to manually intervene. A foot switch function is provided in the feedback module as a key interface for manual intervention. When the tower crane boom enters a stopped state due to reaching a preset dangerous position or being triggered by the automatic obstacle avoidance system, the operator can use the foot switch to rotate in the opposite direction or release the restriction. The foot switch controls the PLC to instruct the electronic control and brake module, start the slewing motor to rotate in the opposite direction, or release the limit control of the boom, allowing the tower crane boom to safely return to the predetermined area.

[0036] In this embodiment, after the automatic obstacle avoidance system of the tower crane is installed, a self-check is performed on the 19# tower crane under the guidance of professionals to ensure that after the hook is retracted to a safe position, the boom rotates in the left and right directions to the dangerous areas on both sides of the 23# tower crane, and check whether there are early warning prompts, automatic power-off and locking functions when reaching the preset designated position. If the protection action is not triggered when reaching the preset position, the vehicle should be stopped immediately and the fault should be checked until the system is sensitive and reliable. When testing the anti-power-off system, ensure that the hook has been retracted to a safe position. Subsequently, in the designated safe area, the boom is quickly swung and the main control power supply in the driver's cab is cut off. At this time, the backup battery power supply is used, and the brake command is output by the system to control the device to move in an inching manner to realize the brake action and stop the boom at the specified angle. If it is found during the test that the backup power supply system cannot operate normally, the main power switch should be restored immediately, the control equipment should stop running, and the fault should be checked until the system recovers to a sensitive and reliable operating state. When the boom is locked and stopped, if the restriction needs to be lifted and the boom needs to be rotated in the opposite direction to a safe area, the operator can use the foot switch to operate in the opposite direction to rotate the boom to a safe area.

[0037] The positioning module of the present invention utilizes a high-precision differential GPS receiver to accurately monitor the movement trajectory and angle changes of the tower crane's lifting arm. The positioning accuracy is high and can provide early warning. The laser radar and ultrasonic sensor of the obstacle monitoring module are combined to realize monitoring of the surrounding environment. The PLC control module analyzes real-time data based on the safety distance algorithm and quickly sends out control signals in danger. The electric control and braking module can cut off the power of the rotary motor in time, and the electromagnetic brake is used to ensure fast and effective braking. The foot switch function of the feedback module allows the operator to manually intervene in an emergency. It effectively solves the problems of relying on manual experience, prone to errors, limited field of view, and difficulty in avoiding collisions when the operating pressure is high in the prior art. It greatly improves the safety level of tower crane operation, reduces the safety hazards caused by human errors or mechanical failures, and ensures the safety of tower crane operation in complex environments.

[0038] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0039] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A tower crane automatic obstacle avoidance system, characterized in that: It includes a positioning module, an obstacle monitoring module, a PLC control module, an electric control and braking module and a feedback module; the positioning module uses a high-precision differential GPS (DGPS) receiver, combined with satellite signals and ground station differential correction signals, to monitor the motion trajectory and angle changes of the tower crane's lifting arm in real time; the obstacle monitoring module uses laser radar and ultrasonic sensors to monitor the surrounding environment of the tower crane in real time; the PLC control module receives real-time data from the positioning module and the obstacle monitoring module to analyze the current position, angle and surrounding environment of the tower crane in real time; the electric control and braking module monitors the real-time data from the positioning module and the obstacle monitoring module, and quickly cuts off the power of the slewing motor when the tower crane enters a dangerous area; the feedback module allows the operator to manually intervene in an emergency through the foot switch function; The PLC control module has an embedded logic control algorithm. When the crane arm approaches the preset danger zone through the data feedback of the positioning module and the obstacle detection module, the PLC control module makes a judgment based on the safety distance algorithm. The calculation formula is: Among them, D cur is the current distance between the tower crane arm and the obstacle, (X arm ,Y arm ) is the current coordinate of the tower crane boom, indicating the position of the tower crane boom, (X obs ,Y obs ) is the coordinate position of the obstacle, and the current distance D between the tower crane boom and the obstacle is calculated. cur From the preset safety distance D safe By comparison, the safety distance D safe It is the minimum distance that must be maintained between the tower crane boom and obstacles.

2. The automatic obstacle avoidance system for a tower crane according to claim 1 is characterized in that ,The positioning module adopts real-time dynamic positioning technology and provides real-time correction information through the base station. The calculation formula of the real-time dynamic positioning technology is: Among them, ρ f is the actual distance between the tower crane and the reference station, (X f -X b ) 2 +(Y f -Y b ) 2 +(Z f -Z b ) 2 is the plane distance between the tower crane and the reference station in three-dimensional space, X f ,Y f ,Z f is the three-dimensional coordinate of the tower crane, X b ,Y b ,Z b is the three-dimensional coordinate of the reference station, ΔL is the differential correction term, which is the correction value sent by the reference station to the tower crane. Through the differential calculation between the reference station and the tower crane, the measurement error is eliminated or reduced to improve the positioning accuracy. The differential correction term ΔL is expressed as: ΔL = ΔL f -ΔL b , where ΔL f is the error term of the tower crane, that is, the error between the distance measured by the tower crane and the actual distance, ΔL b is the error term of the reference station, that is, the error between the distance measured by the reference station and the actual distance.

3. The automatic obstacle avoidance system for a tower crane according to claim 1 is characterized in that The positioning module issues a warning voice prompt when the tower crane arm rotates to the left to 180 degrees or to the right to 140 degrees; the laser radar in the obstacle monitoring module is installed on the top of the tower crane or the front end of the boom, and can scan the surrounding environment 360° in all directions. The ultrasonic sensor is installed at the bottom of the tower crane and the rotating joint of the boom for close-range monitoring of blind spots.

4. The automatic obstacle avoidance system for a tower crane according to claim 1, characterized in that: The PLC control module presets a safety distance D safe is 4 meters. When the boom rotates to the left to 190 degrees or to the right to 150 degrees and D cur <D safe When the safety response mechanism is triggered, a command is sent to the electric control box to cut off the power supply of the slewing motor, instruct the left or right main AC contactor to disconnect, and send a slewing brake action command to the slewing brake until the boom stops completely.

5. The automatic obstacle avoidance system for a tower crane according to claim 1, characterized in that: The electronic control and braking module cuts off the power of the slewing motor by controlling the AC contactor. The power of the slewing motor matches the maximum load capacity of the tower crane. An electromagnetic brake is used. The PLC control module issues an inching brake command, and sufficient braking force can be applied in a very short time after the emergency stop signal.

6. The automatic obstacle avoidance system for a tower crane according to claim 1, characterized in that: The foot switch function of the feedback module allows the operator to control the PLC command electronic control and brake module to start the reverse rotation of the slewing motor or release the limit control when the tower crane boom reaches a dangerous position or stops due to the automatic obstacle avoidance system.

7. The automatic obstacle avoidance system for a tower crane according to claim 1, characterized in that: The differential GPS receiver receives multi-frequency signals from satellites and combines them with differential correction signals from local ground stations to reduce multipath effects, delay errors and spatial error interference factors, providing centimeter-level positioning accuracy.

8. The automatic obstacle avoidance system for a tower crane according to claim 1, characterized in that: The scanning range, accuracy and data processing capability of the laser radar meet the requirements for monitoring the environment around the tower crane, ensuring timely detection of long-distance obstacles; the detection range, sensitivity and response speed of the ultrasonic sensor ensure effective monitoring of the short-range blind spot around the crane arm.

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