A cluster of safety warning robots for highway maintenance operations and its control method

Abstract

This invention belongs to the field of highway maintenance operation warning technology, and relates to a highway maintenance operation safety warning robot cluster and its control method. The safety warning robot cluster includes several highway maintenance operation safety warning robots; each robot includes a mobile chassis and a warning device mounted on the chassis; the warning device is equipped with a depth camera; the mobile chassis is equipped with a GPS positioning unit, a control unit, and a power supply; the control motor, GPS positioning unit, and depth camera are all connected to the control unit. The control method includes a remote control mode and an autonomous control mode; in the remote control mode, an external remote control unit transmits control signals to the control unit, controlling the highway maintenance operation safety warning robot cluster to move to the target position; in the autonomous control mode, the control unit calculates the target position and trajectory of the lead safety warning robot, and controls the lead and following mobile safety warning robots to move to the target position.

Description

Technical Field

[0001] This invention belongs to the field of highway maintenance operation warning technology, and relates to a highway maintenance operation safety warning robot cluster and its control method. Background Technology

[0002] Road transportation, as an indispensable mode of travel in modern society, serves multiple functions including daily commuting, freight transport, and long-distance travel. However, over time, natural environmental factors such as rain erosion, wind and sand abrasion, extreme weather effects, and geological changes continuously challenge road infrastructure, leading to frequent problems such as road surface damage, roadbed settlement, and slope collapse. At the same time, the ever-increasing volume of vehicles, especially the frequent use of heavy and overloaded vehicles, further accelerates road wear and tear, not only shortening the lifespan of roads but also seriously threatening the safety and stability of road traffic. Faced with these challenges, regular road maintenance is particularly important; it is a key measure to ensure road traffic safety, improve road efficiency, and extend the service life of roads. Effective maintenance can promptly identify and repair potential safety hazards, reduce traffic accidents caused by poor road conditions, and protect the safety of people's lives and property. However, the reality is that highway maintenance operations face numerous difficulties: the types of maintenance work are diverse, covering aspects such as road repair, bridge reinforcement, slope management, and drainage system maintenance; work sites are widely and dispersed, ranging from bustling cities to remote villages, from plains to mountainous areas, undoubtedly increasing the complexity and cost of maintenance management. Even more serious is the explosive growth in highway traffic volume in recent years, which has brought unprecedented pressure to highway maintenance operations. To cope with this challenge, investment in highway maintenance has increased year by year, but at the same time, the difficulty of maintenance and the safety risk factor have also risen accordingly. On the one hand, the high volume of traffic means that maintenance work must be completed in the shortest possible time to minimize the impact on traffic; on the other hand, the complex working environment and tight schedules pose significant challenges to the safety of maintenance personnel and equipment.

[0003] Currently, despite advancements in highway maintenance technology, the traditional method of manually placing traffic cones to close off work areas remains prevalent, and it has several shortcomings. First, the sheer number of traffic cones required, especially for long-distance or large-scale maintenance operations, necessitates significant manpower and resources. Second, the long placement distances require maintenance personnel to work for extended periods in high-risk environments, greatly increasing the risk of accidents. Third, the placement efficiency is low, not only prolonging preparation time but also increasing disruption to normal traffic. These problems significantly increase the labor intensity of road maintenance work and make it difficult to effectively guarantee the safety and health of maintenance personnel and the integrity of equipment. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problem that road maintenance operations are labor-intensive and require a lot of manpower and resources, and to provide a safety warning robot cluster for highway maintenance operations and its control method.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a cluster of highway maintenance operation safety warning robots, comprising several highway maintenance operation safety warning robots; each highway maintenance operation safety warning robot includes a mobile chassis and a warning device mounted on the mobile chassis; the warning device is equipped with a depth camera; the mobile chassis is equipped with several moving wheels, and the moving wheels are connected to control motors; the mobile chassis is equipped with a GPS positioning unit, a control unit, and a power supply; the outer wall of the mobile chassis is equipped with an ultrasonic obstacle avoidance sensor connected to the control unit; the control motor, the GPS positioning unit, and the depth camera are all connected to the control unit; the control unit is signal-connected to an external remote control unit.

[0007] A further improvement of the present invention is as follows:

[0008] The warning device includes a cylindrical housing with a warning light on the top; a reflective strip is provided on the outer wall of the cylindrical housing; the control unit includes a trajectory tracking module and a cluster tracking module.

[0009] The outer wall of the mobile chassis is equipped with a warning horn and heat dissipation holes.

[0010] The moving wheel includes a drive wheel and a steering wheel, and the drive wheel and the steering wheel are respectively connected to a control motor.

[0011] Secondly, the present invention provides a control method for the above-mentioned highway maintenance operation safety warning robot cluster, comprising:

[0012] When several highway maintenance safety warning robots arrive at the work road, the depth camera acquires boundary line and lane line information and transmits it to the control unit. The control unit determines the working area of ​​the highway maintenance safety warning robot cluster. The several highway maintenance safety warning robots include one leading safety warning robot and the rest are following mobile safety warning robots.

[0013] The control unit selects a control mode based on the work area; the control mode includes a remote control mode and an autonomous control mode; the remote control mode specifically involves an external remote control unit transmitting control signals to the control unit to control the cluster of highway maintenance operation safety warning robots to move to the target position.

[0014] The autonomous control mode specifically involves the GPS positioning unit and ultrasonic obstacle avoidance sensor transmitting the acquired real-time information to the control unit. The control unit calculates the target position and trajectory of the navigation safety warning robot, controls the navigation safety warning robot to move to the target position, and controls the following mobile safety warning robot to maintain a set distance and angle with the navigation safety warning robot as it moves toward the target position.

[0015] Further improvements are made in the following aspects:

[0016] The control unit calculates the target position and trajectory of the navigation safety warning robot, and controls the navigation safety warning robot to move to the target position as follows:

[0017] The control unit constructs the potential field of the driving lane line, the potential field of the road boundary line, and the potential field of the mobile work vehicle for the navigation safety warning robot using artificial potential field theory. During autonomous movement, the navigation safety warning robot is subjected to the attractive force of the driving lane line, the repulsive force of the road boundary line, and the repulsive force of the mobile work vehicle generated by the artificial potential field. The control unit takes the position where the virtual force on the navigation safety warning robot is zero as its target position, ensuring that the navigation safety warning robot always travels within the specified range and maintains a certain safe distance from the mobile work vehicle during movement in autonomous control mode. The expression for the virtual force on the navigation safety warning robot is as follows:

[0018] F = F la +F bo +F c (1)

[0019] F la =-k l |pL r | 2 (2)

[0020]

[0021] Among them, F la To ensure the optimal positioning of the safety warning robot, which is subject to the gravitational pull of the ideal driving lane line, the robot's best position is on the road boundary line to guide the vehicle and improve driving safety; F bo The repulsive force exerted by the road boundary line on the navigation safety warning robot; F c The repulsive force exerted by the mobile work vehicle behind the leading safety warning robot; k l L is the gravitational potential field constant of the lane line; p is the position vector of the navigation safety warning robot; L r k is the position vector of the lane line; b d is the repulsive potential field constant of the road boundary line; d is the distance from the Navigator safety warning robot to the road boundary line; d bThe influence range of the road boundary; k s d is the repulsive potential field constant of the mobile work vehicle; s The distance between the navigation safety warning robot and the mobile work vehicle in the longitudinal direction; d safe To ensure a safe distance between the navigation safety warning robot and the mobile work vehicle.

[0022] The calculation of the target trajectory of the navigation safety warning robot is as follows:

[0023] The target trajectory is calculated in two parts: the direction of movement and the direction perpendicular to the direction of movement. The expression is as follows:

[0024]

[0025] in, The target trajectory is defined by the direction of the mobile operation. The target trajectory is perpendicular to the direction of the moving operation.

[0026] The trajectory of the target in the direction of the mobile operation is calculated as follows:

[0027] According to the theory of artificial potential fields, during the autonomous movement of the navigation and safety warning robot in the direction of operation, it is subjected to a repulsive force generated by the potential field of the moving vehicle behind it, which affects its target trajectory in the direction of operation. Repulsive force F from mobile work vehicle c The magnitude is related to the distance between the navigation safety warning robot and the mobile work vehicle, which changes and causes a repulsive force F from the work vehicle. c When the direction of movement changes, the target trajectory will also change accordingly to ensure a safe distance between the navigation safety warning robot and the mobile work vehicle. The target trajectory of movement is calculated by the following expression:

[0028]

[0029] Where (x0(t), y0(t)) are the position coordinates of the navigation safety warning robot at the current moment, (x c (t), y c (t) represents the position coordinates of the mobile work vehicle at the current moment; L safe To ensure the minimum safe distance between the navigation safety warning robot and the mobile work vehicle, t a The reaction time for the navigation safety warning robot.

[0030] The calculation of the target trajectory perpendicular to the direction of mobile operation is as follows:

[0031] Perpendicular to the direction of movement, the navigation and safety warning robot is subject to the attractive force of the ideal driving lane line and the repulsive force of the road boundary line during autonomous movement, resulting in a target trajectory perpendicular to the direction of movement. Gravity F with the ideal driving lane line la Repulsive force F with road boundary line bo The size is related to the fact that when the navigation and safety warning robot deviates from the ideal driving lane line during its operation, the attractive force of the ideal driving lane line and the repulsive force of the road boundary line change. The target trajectory calculated in the next moment, perpendicular to the direction of movement, will also change accordingly, enabling the navigation and safety warning robot to travel on the ideal driving lane line and the expected lateral trajectory. It is calculated from the following expression:

[0032]

[0033] Maintaining the preset distance and angle between the following safety warning robot and the leading safety warning robot specifically includes:

[0034] Based on artificial swarm theory, the control unit uses the lateral and longitudinal spacing errors between two adjacent following safety warning robots as state variables of the swarm system, and constructs swarm kinematic equations. This allows the following safety warning robots to surround the moving work vehicle in a certain formation and follow the lead safety warning robot to the target position during autonomous movement. The swarm kinematic expression is as follows:

[0035]

[0036]

[0037] Where, q i ∈R n G is a state variable. ij (·):R n ×R n →R represents the potential field formed by the mutual interaction between safety warning robots i and j. The cumulative influence of each safety warning robot on safety warning robot i affects the moving safety warning robot j. Simultaneously, to ensure that the lateral and longitudinal spacing errors of the safety warning robots tend to zero during movement, an artificial potential field function G is added. iT q represents the spacing error of the i-th safety warning robot. o The expected distance error q between the expected tracking arrival and the expected distance. T The potential field function; a represents the gravitational field, and at the current moment, if the spacing error q of the i-th following warning robot... i The distance error q between the j-th following warning robot j When the difference is large, the i-th safety warning robot and the j-th safety warning robot attract each other, and the expected velocity obtained in the next moment will cause the i-th safety warning robot and the j-th safety warning robot to move closer together; expression Let q represent a repulsive force field. At the current moment, if the spacing error q of the i-th following warning robot... i The distance error q between the j-th following warning robot j When the difference is small, the i-th safety warning robot and the j-th safety warning robot repel each other, and the expected speed calculated in the next moment will cause the i-th safety warning robot and the j-th safety warning robot to move away from each other.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] This invention discloses a cluster of safety warning robots for highway maintenance operations. By introducing several of these robots, the safety and efficiency of highway maintenance operations are significantly improved. These robots possess several advantages: Equipped with advanced sensors such as control units, GPS positioning units, and depth cameras, they can autonomously navigate and locate themselves, ensuring accurate task execution in complex highway environments. The GPS positioning unit provides precise location information, while the depth camera perceives the surrounding three-dimensional environment, providing crucial data support for robot movement and obstacle avoidance. Warning devices on the robots can issue real-time warning signals, alerting passing vehicles to the maintenance work area and effectively reducing traffic accidents. This real-time feedback mechanism is crucial for ensuring the safety of construction personnel and passing vehicles. Ultrasonic obstacle avoidance sensors on the mobile chassis can monitor obstacles ahead in real time, ensuring the robot can flexibly avoid collisions during movement, further enhancing operational safety and stability. Through an external remote control unit connected to the control unit, operators can remotely monitor and control the robot's operating status, adjust work strategies promptly, and respond to emergencies. This remote control capability not only improves operational flexibility but also ensures operator safety. The robot, with its mobile chassis and numerous wheels, possesses excellent terrain adaptability, enabling smooth movement on different types of roads and meeting the needs of various maintenance operations. In summary, this highway maintenance safety warning robot cluster, by integrating advanced intelligent technologies and sensor equipment, achieves efficient and safe monitoring and warning of maintenance work areas, providing strong technical support and assurance for highway maintenance operations.

[0040] Furthermore, the warning unit includes warning lights and a warning horn. The warning lights, located at the top of the cylindrical housing, can attract the driver's attention and improve their perception of warning information through flashing, color changes, and other methods. These warning signals can quickly attract the driver's attention, prompting them to take appropriate actions, such as slowing down, changing lanes, or swerving, to ensure road safety. The warning horn is located at both the front and rear ends of the mobile chassis. The volume of the warning horn can be manually adjusted according to the degree of danger in the working environment, enhancing the warning effect, indicating emergencies, and improving traffic control capabilities, thereby improving road safety.

[0041] This invention discloses a control method for a cluster of safety warning robots used in highway maintenance operations, including a remote control mode and an autonomous control mode, which can be flexibly switched according to different scenarios. In remote control mode, the mobile safety warning robots can be quickly deployed, adjusted, and retrieved; in autonomous mode, the safety warning robots can surround and follow mobile work vehicles in real time within a specified area of ​​the road, significantly reducing the labor intensity of highway maintenance operations and effectively ensuring the safety of construction personnel.

[0042] Furthermore, in the autonomous control mode of the highway maintenance safety warning robot of this invention, the control problem of the safety warning robot swarm is transformed into the trajectory tracking control problem of the leading safety warning robot and the swarm tracking control problem of the following safety warning robots. Artificial potential field theory is used to consider the safety constraints faced by the safety warning robots in different road environments, including the road boundary lines and the positional constraints of the mobile work vehicle relative to the safety warning robots in the lateral and longitudinal directions. This allows the safety warning robot swarm to track and surround the target work vehicle in real time during operation, while maintaining a certain formation and traveling within the prescribed road area. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the structure of a road maintenance safety warning robot according to the present invention;

[0045] Figure 2 This is a schematic diagram of the mobile chassis of a highway maintenance operation safety warning robot according to the present invention;

[0046] Figure 3 This is a flowchart illustrating the control mode selection process for a safety warning robot cluster used in highway maintenance operations, as described in this invention.

[0047] Figure 4 A flowchart illustrating the remote control mode of a safety warning robot cluster for highway maintenance operations in this invention;

[0048] Figure 5 This is a flowchart illustrating the autonomous mode of a highway maintenance operation safety warning robot cluster according to the present invention;

[0049] Figure 6 This is a diagram showing a cluster of safety warning robots for highway maintenance operations working at a highway maintenance site, as described in this invention. Figure 6 (a) is a schematic diagram of the deployment of lane safety warning robots in a two-way six-lane closed inner lane; Figure 6 (b) Schematic diagram of the deployment of the safety warning robot on curved roads;

[0050] Figure 7 This is a schematic diagram of the spacing and angle of the safety warning robot cluster under curved roads in an embodiment of the present invention;

[0051] Figure 8 This is a simulation diagram of the navigation safety warning robot cluster moving and operating in the outer lane of a two-way four-lane closed road and a curved road, according to an embodiment of the present invention. Figure 8 (a) is a schematic diagram of the movement trajectory of a cluster of navigation and safety warning robots on a straight road; Figure 8 (b) is a schematic diagram of the movement trajectory of the navigation safety warning robot and the mobile work vehicle on a straight road; where Figure 8 (c) is a schematic diagram of the movement trajectory of the navigation and safety warning robot on a curved road; Figure 8 (d) is a schematic diagram of the movement trajectory of the navigation safety warning robot and the mobile work vehicle on a curved road;

[0052] Figure 9 This is a simulation diagram of a safety warning robot cluster moving in the outer lane of a two-way four-lane road on a straight road, according to an embodiment of the present invention. Figure 9 (a) is a schematic diagram of the movement trajectory of a cluster of safety warning robots following a straight road; Figure 9 (b) shows the simulation results of the longitudinal spacing error; Figure 9 (c) shows the simulation results of the lateral spacing error;

[0053] Figure 10 This is a simulation diagram of a safety warning robot moving in the outer lane of a two-way four-lane road under a curved road, according to an embodiment of the present invention. Figure 10 (a) is a schematic diagram of the movement trajectory of a cluster of safety warning robots following a curved road; Figure 10 (b) shows the simulation results of the longitudinal spacing error; Figure 10 (c) shows the simulation results of the lateral spacing error.

[0054] The components are: 1-Ultrasonic obstacle avoidance sensor; 2-GPS positioning unit; 3-Cylindrical housing; 4-Depth camera; 5-Reflective strip; 6-Warning light; 7-Warning horn; 8-Drive wheel; 9-Steering wheel; 10-Control motor; 11-Power supply; 12-Heat dissipation hole. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of 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. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0056] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0057] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0058] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0059] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0060] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0061] The present invention is described in further detail below with reference to the accompanying drawings:

[0062] See Figure 1 and Figure 2This invention discloses a cluster of safety warning robots for highway maintenance operations, comprising several highway maintenance safety warning robots. Each robot includes a mobile chassis and a warning device mounted on the chassis. A depth camera 4 is mounted on the warning device. Several wheels are mounted on the mobile chassis, and each wheel is connected to a control motor 10. A GPS positioning unit 2, a control unit, and a power supply 11 are mounted on the mobile chassis. An ultrasonic obstacle avoidance sensor 1, connected to the control unit, is mounted on the outer wall of the mobile chassis. The control motor 10, GPS positioning unit 2, and depth camera 4 are all connected to the control unit. The control unit is signal-connected to an external remote control unit. The warning device includes a cylindrical shell 3, with a warning light 6 on the top. A reflective strip 5 is mounted on the outer wall of the cylindrical shell 3. The control unit includes a trajectory tracking module and a cluster tracking module. A warning horn 7 and heat dissipation holes 12 are mounted on the outer wall of the mobile chassis. Each wheel includes a drive wheel 8 and a steering wheel 9, each connected to a control motor 10. The warning device includes a cylindrical shell, a depth camera, and reflective strips. The cylindrical shell 3 is positioned above the mobile chassis and is detachably connected to it. The cylindrical shell 3 has polygonal grooves, and the depth camera 4 is housed within these grooves. Reflective strips 5 are located on the exterior of the cylindrical shell 3. The mobile chassis includes a control unit, a warning unit, a power supply unit, an obstacle avoidance unit, and a GPS positioning unit. The control unit and power supply unit are both located within the mobile chassis, the drive unit is located below the mobile chassis, the obstacle avoidance unit is located at both ends of the mobile chassis, the warning unit is located on both sides of the obstacle avoidance unit, and the GPS positioning unit is located at the top of the mobile chassis, situated on both sides of the cylindrical shell. The obstacle avoidance unit uses ultrasonic obstacle avoidance sensors 1, located at both ends of the mobile chassis. During the autonomous movement of the safety warning robot, the ultrasonic obstacle avoidance sensors identify surrounding obstacles and measure the real-time distance between the safety warning robot and the obstacles, simultaneously uploading the distance between the safety warning robot and the ultrasonic obstacle avoidance sensors to the control unit. The warning unit includes a warning light 6 and a warning horn 7. The warning light 6 is located on the upper end of the cylindrical housing 3 and is spirally connected to the cylindrical housing 3. The warning horn 7 is located at the front end of the mobile chassis and on both sides of the ultrasonic obstacle avoidance sensor 1. The warning light 6 flashes orange or red light to alert the driver and prompt them to take appropriate action, helping the driver to comply with traffic rules and maintain road traffic order and safety. The drive unit includes a drive wheel 8, a steering wheel 9, and a control motor 10. The drive wheel 8 is located under the mobile chassis, the steering wheel 9 is located on one side of the drive wheel 8, and the control motor 10 is located inside the mobile chassis. The drive unit is used to control the drive wheel to move according to the desired speed sent by the control unit at the current moment, and to control the drive wheel to avoid obstacles according to obstacle avoidance movement commands.The power supply unit includes a power supply 11, which is located at the lower end of the cylindrical housing 3 and inside the mobile chassis. The power supply unit supplies power to the control unit, drive unit, positioning unit, and obstacle avoidance unit. The mobile chassis also includes multiple heat dissipation holes 12; these holes 12 are located on the exterior of the mobile chassis, on the side of the warning horn 7 away from the ultrasonic obstacle avoidance sensor 1.

[0063] See Figure 3 , Figure 4 and Figure 5 This invention provides a control method for a cluster of safety warning robots used in highway maintenance operations, comprising:

[0064] When several highway maintenance safety warning robots arrive at the work road, the depth camera 4 acquires boundary line and lane line information and transmits it to the control unit. The control unit determines the working area of ​​the highway maintenance safety warning robot cluster. The several highway maintenance safety warning robots include one leading safety warning robot and the rest are following mobile safety warning robots.

[0065] The control unit selects a control mode based on the work area; the control mode includes a remote control mode and an autonomous control mode; the remote control mode specifically involves an external remote control unit transmitting control signals to the control unit to control the cluster of highway maintenance operation safety warning robots to move to the target position.

[0066] The autonomous control mode specifically involves the GPS positioning unit 2 and the ultrasonic obstacle avoidance sensor 1 transmitting the acquired real-time information to the control unit. The control unit calculates the target position and target trajectory of the navigation safety warning robot, controls the navigation safety warning robot to move to the target position, and controls the following moving safety warning robot to maintain a set distance and angle with the navigation safety warning robot as it moves toward the target position.

[0067] The following detailed description is provided in conjunction with specific embodiments:

[0068] 1) After the safety warning robot arrives at the work road, it turns on the warning light 6 and the warning horn 7; the depth camera 4 acquires boundary line and lane line information to determine the working area of ​​the safety warning robot;

[0069] According to the "Highway Maintenance Safety Operation Regulations," when carrying out road maintenance operations, safety warning robots should be deployed in the control area in the following order: warning zone, upstream transition zone, longitudinal buffer zone, working zone, downstream transition zone, and termination zone. Depth camera 4, as a sensor in the perception system, is used to collect anticipated information about the highway. The depth camera sends the acquired road image information to the controller. Based on the identified lane boundary line information, the controller determines the position information of the lane dividing lines, treating the highway as a structural road, with lane lines approximating straight lines. Under different working conditions, the safe working area of ​​the safety warning robot is determined based on the lane line information.

[0070] 2) Select the appropriate mode based on different work scenarios;

[0071] The safety warning robot proposed in this invention is applicable to different road operation scenarios, and the control mode selection includes remote control mode and autonomous mode. Specifically, highway maintenance operations can be divided into temporary operations and mobile operations. Temporary operations include road repair, handling traffic accidents, and repairing road cracks, while mobile operations include road cleaning, hedge maintenance, and road marking.

[0072] For temporary operations, the deployment and retrieval of safety warning robots can be completed using remote control mode. In remote control mode, the remote controller and multiple safety warning robots are pre-paired with receivers, and different ID names are set on the remote controller. During remote control, the ID names are changed sequentially by the remote controller to achieve individual sequential control of multiple safety warning robots. The control unit receives speed commands, steering commands, and braking commands transmitted by the remote controller to achieve real-time control of the mobile safety warning robots.

[0073] During mobile operations, a hybrid control mode combining remote control and autonomous operation can be employed. Remote control is used to initially position the safety warning robots. During mobile operations, autonomous operation is used to guide the robots. In autonomous mode, depth camera 4 automatically identifies lane lines and movement space, combined with real-time GPS positioning. Simultaneously, information acquired by ultrasonic obstacle avoidance sensor 1 is sent to the control unit. The control unit calculates the movement commands for each safety warning robot at the next moment, ensuring a safe distance between the robots upon reaching the destination. During autonomous navigation, road lane lines are automatically identified as boundaries of the movement space, ensuring that the safety warning robots do not cross lane lines and maintaining a safe distance between them upon reaching the destination. Throughout the entire operation, the warning and alarm platform remains continuously operational, alerting oncoming vehicles.

[0074] 3) In remote control mode, the specific steps are as follows;

[0075] Step 1: Manually remotely control the safety warning robot to the destination and determine if it has crossed the lane boundary line; if yes, proceed to the next step; otherwise, reach the destination. Step 2: Warning light 6 changes from constant on to flashing. Step 3: Manually adjust the position and posture of the safety warning robot; and repeat Step 1. During operation, each safety warning robot has a fixed placement position, and the position remains unchanged during operation. Under this condition, the single safety warning robot remote control mode is used, which allows for rapid deployment, adjustment, and retrieval by manual remote control. In autonomous mode, if the safety warning robot does not travel according to the planned path or fails to effectively avoid obstacles, it is necessary to switch from autonomous mode to remote control mode.

[0076] 4) In autonomous mode, the specific steps are as follows:

[0077] Step 1: Determine the safe working area for the safety warning robot;

[0078] After the safety warning robot arrives at the work road, it is first quickly deployed using remote control mode. Then, depth camera 4 acquires image information of the road ahead and sends it to the control unit. The control unit uses the identified lane boundary line information as the boundary line of the safe working area, and treats the highway as a structured road, with lane lines approximating straight lines, thereby determining the safe working area of ​​the safety warning robot.

[0079] Step 2: Determine the desired location of the navigation safety warning robot;

[0080] In this invention, the first safety warning robot in the direction of movement within the safety warning robot cluster is designated as the lead warning robot, while the remaining safety warning robots serve as follower warning robots. During autonomous movement, the lead warning robot needs to maintain a safe distance ahead of the mobile work vehicle and travel at the same speed within the designated road. Its control unit receives road image information from the depth camera 4 and precise position information of the safety warning robots and the mobile work vehicle from the GPS unit. Simultaneously, the trajectory tracking function within the control unit uses artificial potential field theory to represent the influence of this constraint on the safety warning robot as an artificial potential field and analyzes its virtual force. The lead warning robot takes the zero point of the resultant force of this virtual force as its desired position. The desired position of the lead warning robot at the current moment can be calculated using the following formula:

[0081] F = F la +F bo +F c ,

[0082] Where, F la =-k l |pL r | 2 ,

[0083]

[0084] Among them, F la The gravitational pull of the ideal driving lane line on the navigation warning robot; F bo The repulsive force exerted by the road boundary line on the navigation and warning robot; F c The repulsive force of the mobile work vehicle behind the navigation and warning robot; k l Let p be the gravitational potential field constant of the lane line, and L be the position vector of the navigation safety warning robot. r k is the position vector of the lane line. b Let d be the repulsive potential field constant of the road boundary line, and d be the distance from the Navigator safety warning robot to the road boundary line. b k represents the influence range of the road boundary. s Let d be the repulsive potential field constant of the mobile work vehicle. s To determine the longitudinal distance between the navigation safety warning robot and the mobile work vehicle, d safe To ensure a safe distance between the navigation safety warning robot and the mobile work vehicle.

[0085] F la To ensure the optimal positioning of the safety warning robot, which is subject to the gravitational pull of the ideal driving lane line, the robot's best position is on the road boundary line to guide the vehicle and improve driving safety; F bo The repulsive force exerted on the navigation and warning robot by the road boundary line increases as the robot gets closer to the boundary line. In the next instant, the robot will move away from the boundary line, while the repulsive force gradually decreases. c To mitigate the repulsive force from the mobile work vehicle behind the navigation and warning robot, the robot treats the mobile work vehicle as an obstacle during its autonomous movement and maintains a safe distance from it at all times. When the distance between the navigation and warning robot and the mobile work vehicle is less than the safe distance, the repulsive force on the robot increases, and the robot will gradually move away from the mobile work vehicle in the next moment.

[0086] Step 3: Calculate the expected trajectory of the navigation safety warning robot;

[0087] After obtaining the desired position, the trajectory tracking function within the control unit of the navigation and warning robot further calculates the desired trajectory based on the virtual force generated by the artificial potential field. The desired trajectory of the navigation and warning robot can be divided into two directions: longitudinal (road driving direction) and lateral (perpendicular to the road driving direction). The desired trajectory can be calculated by the following formula:

[0088]

[0089] Among them, the longitudinal expected trajectory The repulsive force F of the mobile work vehicle can be used to achieve this.c The calculation yields:

[0090]

[0091] Lateral expected trajectory Gravity F of the ideal driving lane line la Repulsive force F with road boundary line bo The calculation yields:

[0092]

[0093] Where (x0(t), y0(t)) are the position coordinates of the navigation safety warning robot at the current moment, (x c (t), y c (t) represents the position coordinates of the mobile work vehicle at the current moment; L safe To ensure the minimum safe distance between the navigation safety warning robot and the mobile work vehicle, t a The reaction time for the navigation safety warning robot.

[0094] Step 4: The safety warning robots form different patterns under different working conditions. Each robot obtains its own location information under the help of GPS. It should be noted that the position of the safety warning robots is fixed after the pattern is determined.

[0095] According to the "Highway Maintenance Safety Operation Regulations," during road maintenance operations, safety warning robots should be deployed in the control area in the following order: warning zone, upstream transition zone, longitudinal buffer zone, work zone, downstream transition zone, and termination zone. Depending on the task, function, and traffic volume, highways can be classified into different levels, and the control length of road maintenance operations also varies, thus requiring different numbers of safety warning robots. Because there are many highway maintenance operation scenarios, to reduce the complexity of method design and application, this invention summarizes road maintenance operation scenarios into: straight road maintenance operations and curved road maintenance operations. For maintenance operations on straight roads, taking a two-way six-lane road as an example, the deployment form of the safety warning robots is as follows: Figure 6 As shown in (a), when performing maintenance work on highways with six or more lanes, the closed lane should also close one side of the adjacent lane, and two upstream transition zones should be arranged, with a minimum distance of more than 200 meters between the two upstream transition zones; for maintenance work on curved roads, the safety warning robots should be deployed in formation, such as... Figure 6 As shown in (b), in order to ensure the compactness of the safety warning robot cluster formation and reduce safety hazards during operation, the starting point of the warning zone should be located at the starting point of the curve, and the length of the warning zone should not exceed the minimum length of 200 meters.

[0096] Step 5: Based on the final encirclement pattern, each following warning robot maintains a certain distance and angle from the leading warning robot, and drives towards the final destination. It is determined whether the lane boundary line has been crossed. If so, proceed to the next step; otherwise, the destination has been reached.

[0097] In autonomous mode, each following warning robot obtains its own position and the positions of adjacent warning robots via GPS. Using the cluster tracking function of the control unit, it selects the lateral and longitudinal spacing errors between two adjacent safety warning robots as the state variables of the cluster system, constructs a cluster kinematic model, determines the positions between adjacent safety warning robots at the current moment, and maintains the safety warning robots moving in a fixed formation. The expression for its cluster kinematic model is as follows:

[0098]

[0099] In the formula,

[0100]

[0101] Where, q i ∈R n G represents the spacing error of the i-th safety warning robot. ij (·):R n ×R n →R represents the potential field formed by safety warning robots i and j. The cumulative influence of each safety warning robot on safety warning robot i affects safety warning robot j. a, b ij and c ij Both are constants greater than zero and b ij >a. Select different parameters according to the specific formation requirements.

[0102] (x i y i Let be the position of the i-th safety warning robot in the inertial coordinate system. Let be the expected longitudinal spacing of the i-th safety warning robot. Let G be the desired lateral spacing of the i-th safety warning robot. To minimize the lateral and longitudinal spacing errors during the robot's movement, an artificial potential field function G is added. iT q represents the spacing error of the i-th safety warning robot. i The expected distance error q between the expected tracking arrival and the expected distance. T The potential field function.

[0103] Parameter a represents the gravitational field. If the distance error q of the i-th following warning robot at the current moment... i The distance error q between the j-th following warning robot jWhen the difference is large, the i-th following warning robot and the j-th following warning robot will attract each other, and the expected speed calculated in the next moment will cause the i-th warning robot and the j-th warning robot to move closer to each other.

[0104] expression Represents a repulsive force field, where the spacing error q of the i-th following warning robot... i The distance error q between the j-th following warning robot j When the difference is small, the i-th warning robot and the j-th warning robot repel each other, and the expected speed calculated in the next step will cause the i-th warning robot and the j-th warning robot to move away from each other.

[0105] like Figure 7 As shown, the kinematic equations of the cluster under curved roads are consistent with those under straight roads, the difference being the longitudinal expected spacing. and lateral expected spacing The design is based on the kinematic model of a straight road, and the cluster kinematic model is flexibly adjusted according to different curvature radii of curves.

[0106] Step 6: Warning light 6 changes from solid to flashing;

[0107] Step 7: The safety warning robot, which has exceeded the lane boundary line, autonomously adjusts its position and posture, and repeats step 5.

[0108] To verify the correctness and effectiveness of the trajectory tracking control of the autonomous mode-guided safety warning robot, a numerical simulation of its trajectory tracking system was conducted using Matlab simulation software. The work scenario was a maintenance operation of a mobile work vehicle on a straight and curved section of a two-way four-lane closed outer lane. The ode45 function was used to verify the trajectory tracking control algorithm. The dynamic parameters of the guided safety warning robot in this simulation were: robot mass m = 3.5 kg; distance d = 0.1 m from the robot's geometric center to its center of mass along the x-axis; and moment of inertia I = 3 kg·m⁻². 2 The distance from the robot's drive wheel to the axis of symmetry is R = 0.23m; the radius of the drive wheel is r = 0.036m; the initial conditions are:

[0109] x0(0)=10, y0(0)=0.1, θ0(0)=3°;

[0110]

[0111] Working Condition 1: Maintenance work on the outer lane of a straight, two-way, four-lane road, with both sides closed;

[0112] Take L ref =0,d bo =0.2,La =10,t a =3; Considering the movement of the mobile work vehicle during actual operation: the speed of the mobile work vehicle is 4km / h = 1.11m / s, and the starting acceleration is taken as 1.310m / s². 2 The motion equations for the mobile work vehicle are as follows:

[0113]

[0114] Working Condition 2: Maintenance work on the outer lane of a curved four-lane road with both directions closed.

[0115] Considering that the mobile work vehicle will slow down during actual operations on curves, the safe distance d between the mobile work vehicle and the navigation safety warning robot is as follows. safe Ignoring the speed of the mobile work vehicle, let d safe =l safe and a fixed safety distance l safe Given the arc length, the motion equation of the mobile work vehicle is designed as follows:

[0116]

[0117] Simulation results of trajectory tracking control for the navigation safety warning robot are as follows: Figure 8 As shown in the simulation results, the navigation safety warning robot can track the desired trajectory well, and at the same time, the navigation safety warning robot always maintains a safe distance from the mobile work vehicle during the process, which verifies the correctness and effectiveness of the trajectory tracking control of the navigation safety warning robot designed in this invention.

[0118] Meanwhile, to verify the correctness and effectiveness of the designed autonomous mode tracking control for the safety warning robot swarm, numerical simulations were conducted using Matlab simulation software on both straight and curved road conditions. The ode45 function was used in Matlab to perform numerical simulations of the safety warning robot swarm tracking control on both straight and curved roads. Since a large number of safety warning robots are used in actual applications, simulations were conducted using 14 robots on a straight road and 4 robots on a curved road as examples. The main dynamic parameters of the safety warning robots on straight and curved roads are as follows.

[0119] Working Condition 1: Maintenance work on the outer lane of a straight, two-way, four-lane road, with both sides closed;

[0120] The simulation parameters are set as follows: a = 0.01, b ij =0.01, c ij =2, α=0.07, κ i=20, m=3.5kg, d=0.1m, I=3(kg·m 2 ), R = 0.23m, r = 0.039m; the initial information of the navigation safety warning robot is: x0 = 15, y0 = 0, θ0 = 0°, x0(t) = 15 + 0.02t 2 y0(t) = 0, and the initial velocity of the remaining 13 following safety warning robots is 0. Their initial postures are shown in the table below:

[0121]

[0122] Working Condition 2: Maintenance work on the outer lane of a curved four-lane road with both directions closed;

[0123] The simulation parameters are set as follows: a = 0.01, b ij =0.01, c ij =2, α=2, k i =20, m=3.5kg, d=0.1m, I=3(kg·m 2 R = 0.23m, r = 0.039m; The simulation parameters of the leading safety warning robot are: x0(t) = 30sin(t), y0(t) = 30cos(t); The initial postures of the other three following safety warning robots are: x1 = -3, y1 = 33, θ1 = 2°; x2 = -7, y2 = 32, θ2 = 3°; x3 = -12, y3 = 30, θ3 = 0°.

[0124] Simulation results of cluster tracking control of safety warning robots are as follows: Figure 9 , 10 As shown, Figure 9 (a) Figure 10 (a) shows the motion trajectories of the safety warning robots on straight and curved roads, respectively. The figures demonstrate that the robot swarm ultimately forms the desired formation when operating in different road environments. Figure 9 As can be seen from (b), 9(c), 10(b) and 10(c), the lateral and longitudinal spacing errors of the safety warning robot tend to be zero during autonomous movement, which verifies the correctness and effectiveness of the designed cluster tracking control.

[0125] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A control method for a cluster of safety warning robots for highway maintenance operations, characterized in that, include: When several highway maintenance operation safety warning robots arrive at the work road, the depth camera (4) acquires the boundary line and lane line information and transmits it to the control unit. The control unit determines the working area of ​​the highway maintenance operation safety warning robot cluster. The several highway maintenance operation safety warning robots include a leading safety warning robot and the rest are following mobile safety warning robots. The control unit selects a control mode based on the work area; the control mode includes a remote control mode and an autonomous control mode; the remote control mode specifically involves an external remote control unit transmitting control signals to the control unit to control the cluster of highway maintenance operation safety warning robots to move to the target position. The autonomous control mode specifically involves the GPS positioning unit (2) and the ultrasonic obstacle avoidance sensor (1) transmitting the acquired real-time information to the control unit. The control unit calculates the target position and target trajectory of the navigation safety warning robot, controls the navigation safety warning robot to move to the target position, and controls the following mobile safety warning robot and the navigation safety warning robot to always maintain the set distance and angle and move towards the target position. The control unit calculates the target position and trajectory of the navigation safety warning robot, and controls the navigation safety warning robot to move to the target position as follows: The control unit constructs the potential field of the driving lane line, the potential field of the road boundary line, and the potential field of the mobile work vehicle for the navigation safety warning robot using artificial potential field theory. During autonomous movement, the navigation safety warning robot is subjected to the attractive force of the driving lane line, the repulsive force of the road boundary line, and the repulsive force of the mobile work vehicle generated by the artificial potential field. The control unit takes the position where the virtual force on the navigation safety warning robot is zero as its target position, ensuring that the navigation safety warning robot always travels within the specified range and maintains a certain safe distance from the mobile work vehicle during movement in autonomous control mode. The expression for the virtual force on the navigation safety warning robot is as follows: F=F la +F bo +F c (1) F la =-k l |p-L r | 2 (2) Among them, F la To ensure the optimal positioning of the safety warning robot, which is subject to the gravitational pull of the ideal driving lane line, the robot's best position is on the road boundary line to guide the vehicle and improve driving safety; F bo The repulsive force exerted by the road boundary line on the navigation safety warning robot; F c The repulsive force exerted by the mobile work vehicle behind the leading safety warning robot; k l L is the gravitational potential field constant of the lane line; p is the position vector of the navigation safety warning robot; L r k is the position vector of the lane line; b d is the repulsive potential field constant of the road boundary line; d is the distance from the Navigator safety warning robot to the road boundary line; d b The influence range of the road boundary; k s d is the repulsive potential field constant of the mobile work vehicle; s The distance between the navigation safety warning robot and the mobile work vehicle in the longitudinal direction; d safe To ensure a safe distance between the navigation safety warning robot and the mobile work vehicle.

2. The control method for a cluster of safety warning robots for highway maintenance operations according to claim 1, characterized in that, The calculation of the target trajectory of the navigation safety warning robot is as follows: The target trajectory is calculated in two parts: the direction of movement and the direction perpendicular to the direction of movement. The expression is as follows: in, The target trajectory is defined by the direction of the mobile operation. The target trajectory is perpendicular to the direction of the moving operation.

3. The control method for a cluster of safety warning robots for highway maintenance operations according to claim 2, characterized in that, The trajectory of the target in the direction of the mobile operation is calculated as follows: According to the theory of artificial potential fields, during the autonomous movement of the navigation and safety warning robot in the direction of operation, it is subjected to a repulsive force generated by the potential field of the moving vehicle behind it, which affects its target trajectory in the direction of operation. Repulsive force F from mobile work vehicle c The magnitude is related to the distance between the navigation safety warning robot and the mobile work vehicle, which changes and causes a repulsive force F from the work vehicle. c When the direction of movement changes, the target trajectory will also change accordingly to ensure a safe distance between the navigation safety warning robot and the mobile work vehicle. The target trajectory of movement is calculated by the following expression: Where (x0(t), y0(t)) are the position coordinates of the navigation safety warning robot at the current moment, (x c (t), y c (t) represents the position coordinates of the mobile work vehicle at the current moment; L safe To ensure the minimum safe distance between the navigation safety warning robot and the mobile work vehicle, t a The reaction time for the navigation safety warning robot.

4. The control method for a cluster of safety warning robots for highway maintenance operations according to claim 3, characterized in that, The calculation of the target trajectory perpendicular to the direction of mobile operation is as follows: Perpendicular to the direction of movement, the navigation and safety warning robot is subject to the attractive force of the ideal driving lane line and the repulsive force of the road boundary line during autonomous movement, resulting in a target trajectory perpendicular to the direction of movement. Gravity F with the ideal driving lane line la Repulsive force F with road boundary line bo The size is related to the fact that when the navigation and safety warning robot deviates from the ideal driving lane line during its operation, the attractive force of the ideal driving lane line and the repulsive force of the road boundary line change. The target trajectory calculated in the next moment, perpendicular to the direction of movement, will also change accordingly, enabling the navigation and safety warning robot to travel on the ideal driving lane line and the expected lateral trajectory. It is calculated from the following expression:

5. The control method for a cluster of safety warning robots for highway maintenance operations according to claim 4, characterized in that, Maintaining the preset distance and angle between the following safety warning robot and the leading safety warning robot specifically includes: Based on artificial swarm theory, the control unit uses the lateral and longitudinal spacing errors between two adjacent following safety warning robots as state variables of the swarm system, and constructs swarm kinematic equations. This allows the following safety warning robots to surround the moving work vehicle in a certain formation and follow the lead safety warning robot to the target position during autonomous movement. The swarm kinematic expression is as follows: Where, q i ∈R n G is a state variable. ij (·):R n ×R n →R represents the potential field formed by the mutual interaction between safety warning robots i and j. The cumulative influence of each safety warning robot on safety warning robot i affects the moving safety warning robot j. Simultaneously, to ensure that the lateral and longitudinal spacing errors of the safety warning robots tend to zero during movement, an artificial potential field function G is added. iT q represents the spacing error of the i-th safety warning robot. i The expected distance error q between the expected tracking arrival and the expected distance. T The potential field function; a represents the gravitational field, and at the current moment, if the spacing error q of the i-th following warning robot... i The distance error q between the j-th following warning robot j When the difference is large, the i-th safety warning robot and the j-th safety warning robot attract each other, and the expected velocity obtained in the next moment will cause the i-th safety warning robot and the j-th safety warning robot to move closer together; expression Let q represent a repulsive force field. At the current moment, if the spacing error q of the i-th following warning robot... i The distance error q between the j-th following warning robot j When the difference is small, the i-th safety warning robot and the j-th safety warning robot repel each other, and the expected speed calculated in the next moment will cause the i-th safety warning robot and the j-th safety warning robot to move away from each other.

6. A cluster of safety warning robots for highway maintenance operations using the method described in any one of claims 1-5, characterized in that, The system includes several highway maintenance operation safety warning robots; each highway maintenance operation safety warning robot includes a mobile chassis and a warning device installed on the mobile chassis; the warning device is equipped with a depth camera (4); the mobile chassis is equipped with several moving wheels, and the moving wheels are connected to a control motor (10); the mobile chassis is equipped with a GPS positioning unit (2), a control unit and a power supply (11); the outer wall of the mobile chassis is equipped with an ultrasonic obstacle avoidance sensor (1) connected to the control unit; the control motor (10), the GPS positioning unit (2) and the depth camera (4) are all connected to the control unit; the control unit is signal-connected to an external remote control unit.

7. The highway maintenance operation safety warning robot cluster according to claim 6, characterized in that, The warning device includes a cylindrical housing (3), and a warning light (6) is provided on the top of the cylindrical housing (3); a reflective strip (5) is provided on the outer wall surface of the cylindrical housing (3); the control unit includes a trajectory tracking module and a cluster tracking module.

8. The highway maintenance operation safety warning robot cluster according to claim 7, characterized in that, The outer wall of the mobile chassis is provided with a warning horn (7) and heat dissipation holes (12).

9. The highway maintenance operation safety warning robot cluster according to claim 8, characterized in that, The moving wheel includes a drive wheel (8) and a steering wheel (9), and the drive wheel (8) and the steering wheel (9) are respectively connected to a control motor (10).

Images