Road maintenance operation safety warning robot cluster and control method thereof

Abstract

The invention belongs to the technical field of highway maintenance operation warning, and relates to a highway maintenance operation safety warning robot cluster and a control method thereof. The safety warning robot cluster comprises a plurality of road maintenance operation safety warning robots; the road maintenance operation safety warning robot comprises a movable chassis and a warning device arranged on the movable chassis. A depth camera is arranged on the warning device; a GPS positioning unit, a control unit and a power supply are arranged on the movable chassis; the control motor, the GPS positioning unit and the depth camera are all connected with the control unit. The control method comprises a remote control mode and an autonomous control mode. According to the remote control mode, an external remote control unit transmits a control signal to the control unit, and the road maintenance operation safety warning robot cluster is controlled to move to a target position. In the autonomous control mode, the control unit calculates the target position and the target track of the navigation safety warning robot and controls the navigation safety warning robot and the following moving safety warning robot to move to the target position.

Description

Technical Field

[0001] The invention belongs to the technical field of highway maintenance operation warning, and relates to a highway maintenance operation safety warning robot cluster and a control method thereof. Background Art

[0002] Road transportation, as one of the indispensable modes of travel in modern society, carries multiple functions such as daily commuting, cargo transportation, and long-distance travel. However, with the passage of time, natural environmental factors such as rain erosion, wind and sand wear, extreme weather impacts, and geological changes continue to pose challenges to road infrastructure, resulting in frequent problems such as road damage, roadbed settlement, and slope landslides. At the same time, the growing volume of vehicles, especially the frequent use of heavy vehicles and overloaded vehicles, has further aggravated the rate of road wear, which not only shortens the service life of the road, but also seriously threatens the safety and stability of road traffic. In the face of this series of challenges, regular maintenance and maintenance of roads is particularly important. It is a key measure to ensure road traffic safety, improve road traffic efficiency, and extend the service life of roads. Effective maintenance work can timely discover and repair potential safety hazards, reduce traffic accidents caused by poor road conditions, and protect people's lives and property. However, the reality is that highway maintenance operations face many difficulties: there are many types of maintenance operations, covering road repair, bridge reinforcement, slope management, drainage system maintenance and many other aspects; the operation points are widely distributed and scattered, from bustling cities to remote villages, from plains to mountainous areas, which undoubtedly increases the complexity and cost of maintenance management. What is more serious is that the traffic volume on roads has shown explosive growth in recent years, which has brought unprecedented pressure to highway maintenance operations. In order to meet this challenge, the 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. On the one hand, the high-intensity traffic volume requires maintenance operations to be completed in the shortest possible time to reduce the impact on traffic; on the other hand, the complex working environment and tight construction period make the safety of maintenance personnel and equipment face great challenges.

[0003] At present, despite the progress in highway maintenance technology, in actual operations, the manual placement of traffic cones is still widely used to close the work area. This traditional method has many shortcomings. First, the number of traffic cones placed is huge, especially in long-distance or large-scale maintenance operations, which requires a lot of manpower and material resources; second, the long placement distance requires maintenance personnel to work for a long time in a high-risk environment, which is very prone to safety accidents; third, the placement efficiency is low, which not only prolongs the preparation time for maintenance operations, but also increases interference with normal traffic. These problems not only greatly increase the labor intensity of road maintenance operations, but also make it difficult to effectively guarantee the safety and health of maintenance workers and the integrity of operating equipment. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problem in the prior art that road maintenance operations are labor-intensive and require a large amount of manpower and material resources, and to provide a highway maintenance operation safety warning robot cluster and a control method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

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

[0007] The present invention is further improved in that:

[0008] The warning device comprises a cylindrical shell, a warning light is arranged on the top of the cylindrical shell; a reflective strip is arranged on the outer wall surface of the cylindrical shell; and the control unit comprises a trajectory tracking module and a cluster tracking module.

[0009] A warning horn and heat dissipation holes are arranged on the outer wall surface of the mobile chassis.

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

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

[0012] When a plurality of highway maintenance operation safety warning robots arrive at the working road, the depth camera obtains boundary line and lane line information and transmits it to the control unit, and the control unit determines the working area of ​​the highway maintenance operation safety warning robot cluster; the plurality of highway maintenance operation safety warning robots include a pilot safety warning robot and the rest are follow-up mobile safety warning robots;

[0013] The control unit selects a control mode based on the working area; the control mode includes a remote control mode and an autonomous control mode; the remote control mode is specifically that an external remote control unit transmits a control signal to the control unit to control the highway maintenance operation safety warning robot cluster to move to a target position;

[0014] The autonomous control mode is specifically that the GPS positioning unit and ultrasonic obstacle avoidance sensor transmit the acquired real-time information to the control unit, the control unit calculates the target position and target trajectory of the pilot safety warning robot, controls the pilot safety warning robot to move to the target position, and controls the following mobile safety warning robot to always maintain the set distance and angle with the pilot safety warning robot and move to the target position.

[0015] Further improvements are:

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

[0017] The control unit constructs the driving lane line potential field, boundary line potential field and mobile work vehicle potential field of the pilot safety warning robot through the artificial potential field theory. During the autonomous movement of the pilot safety warning robot, the driving lane line attraction, road boundary line repulsion and mobile work vehicle repulsion generated by the artificial potential field are exerted; the control unit takes the position where the virtual force exerted on the pilot safety warning robot is zero as its target position, so that the pilot safety warning robot always drives within the specified range and maintains a certain safe distance from the mobile work vehicle during the movement in the autonomous control mode; the virtual force exerted on the pilot safety warning robot is expressed 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 The ideal driving lane line gravity for the pilot safety warning robot. The best position of the safety warning robot is on the road boundary line of the vehicle to guide the vehicle and improve driving safety. bo F is the repulsive force of the road boundary line on the navigation safety warning robot; c To warn the robot of the repulsion of the mobile working vehicle behind it for safety; k l is the gravitational potential field constant of the lane line; p is the position vector of the pilot safety warning robot; L r is the position vector of the lane line; k b is the repulsive potential field constant of the road boundary line; d is the distance from the pilot safety warning robot to the road boundary line; d bis the influence range of the road boundary; k s is the repulsive potential field constant of the mobile working vehicle; d s The distance between the navigation safety warning robot and the mobile working vehicle in the longitudinal direction; d safe To ensure safe distance between the robot and the mobile work vehicle, the pilot can warn the robot of the safe distance between the robot and the mobile work vehicle.

[0022] The target trajectory of the pilot safety warning robot is calculated as follows:

[0023] The target trajectory is divided into the moving operation direction and the vertical direction of the moving operation direction for calculation, and the expression is as follows:

[0024]

[0025] in, The target trajectory of the moving operation direction; It is the target trajectory perpendicular to the moving operation direction.

[0026] The calculation of the target trajectory of the moving operation direction is:

[0027] According to the artificial potential field theory, in the moving operation direction, the pilot safety warning robot is subjected to the repulsive force generated by the potential field of the mobile operation vehicle behind it during its autonomous movement, and its moving operation direction target trajectory Repulsion F with mobile working vehicle c When the distance between the pilot safety warning robot and the mobile working vehicle changes, the repulsive force F c When it changes, the target trajectory of the moving operation direction will also change to ensure the safe distance between the pilot safety warning robot and the mobile operation vehicle. The target trajectory of the moving operation direction is calculated by the following expression:

[0028]

[0029] Among them, (x0(t), y0(t)) is the position coordinate of the pilot safety warning robot at the current moment, (x c (t), y c (t)) is the position coordinate of the mobile working vehicle at the current moment; L safe is the minimum safe distance between the pilot safety warning robot and the mobile working vehicle, t a The response time of the robot for pilot safety warning.

[0030] The calculation of the target trajectory perpendicular to the moving operation direction is:

[0031] In the process of autonomous movement, the pilot safety warning robot is affected by the gravitational force of the ideal driving lane line and the repulsive force of the road boundary line in the direction perpendicular to the moving operation direction, and moves perpendicular to the target trajectory in the moving operation direction. The gravitational force F of the ideal driving lane line la Repulsion F with road boundary line bo When the pilot safety warning robot deviates from the ideal driving lane line during driving, the gravitational force of the ideal driving lane line and the repulsive force of the road boundary line change, and the target trajectory perpendicular to the moving operation direction calculated at the next moment will also change accordingly, so that the pilot safety warning robot can drive on the ideal lane line and the lateral desired trajectory It is calculated by the following expression:

[0032]

[0033] Controlling the following mobile safety warning robot and the pilot safety warning robot to always maintain a set distance and angle specifically includes:

[0034] According to the artificial cluster theory, the control unit takes the lateral spacing error and the longitudinal spacing error between two adjacent following safety warning robots as the state variables of the cluster system, and constructs the cluster kinematic equation, so that the following safety warning robots surround the mobile working vehicle in a certain formation during the autonomous movement and follow the leading safety warning robot to move to the target position. The cluster kinematic expression is as follows:

[0035]

[0036]

[0037] Among them, q i ∈R n is the state variable, G ij (·):R n ×R n →R represents the potential field formed by the safety warning robots i and j. The influence of each safety warning robot on the safety warning robot i is accumulated and acts on the mobile safety warning robot j. At the same time, in order to make the horizontal and vertical spacing errors of the safety warning robots approach zero during movement, an artificial potential field function G is added. iT , represents the spacing error q of the i-th safety warning robot i The expected distance error q with the expected tracking arrival T potential field function; a represents the gravitational field. At the current moment, if the spacing error q of the i-th following warning robot i The distance error q with the jth 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 speed at the next moment will make the i-th safety warning robot and the j-th safety warning robot approach each other; the expression is Represents the repulsive field. At the current moment, if the distance error q of the i-th following warning robot i The distance error q with the jth 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 at the next moment will make the i-th safety warning robot and the j-th safety warning robot move away from each other.

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

[0039] The invention discloses a highway maintenance operation safety warning robot cluster, which significantly improves the safety and efficiency of highway maintenance operations by introducing a number of highway maintenance operation safety warning robots. These robots have the following advantages: by being equipped with advanced sensors such as a control unit, a GPS positioning unit, and a depth camera, these robots can autonomously navigate and locate, ensuring accurate execution of tasks in a complex highway environment. The GPS positioning unit provides accurate location information, while the depth camera can sense the surrounding three-dimensional environment, providing key data support for the robot's movement and obstacle avoidance. The warning device set on the robot can send out a warning signal in real time to remind passing vehicles to pay attention to the maintenance operation area, effectively reducing the occurrence of traffic accidents. This instant feedback mechanism is crucial to ensuring the safety of construction personnel and passing vehicles. The ultrasonic obstacle avoidance sensor equipped on the mobile chassis can monitor the obstacles in front in real time, ensuring that the robot can flexibly avoid them during movement and avoid collisions with surrounding objects, further improving the safety and stability of the operation. Through an external remote control unit connected to the control unit signal, the operator can remotely monitor and control the operation status of the robot, adjust the operation strategy in time, and respond to emergencies. This remote control capability not only improves the flexibility of the operation, but also ensures the safety of the operator. The robot adopts a mobile chassis and several mobile wheels, has good terrain adaptability, can move smoothly on different types of roads, and meet the needs of various maintenance operations. In summary, the highway maintenance operation safety warning robot cluster integrates advanced intelligent technology and sensor equipment to achieve efficient and safe monitoring and warning of the maintenance operation area, providing strong technical support and guarantee for highway maintenance operations.

[0040] Furthermore, the warning unit includes a warning light and a warning horn. The warning light is arranged at the upper end of the cylindrical shell, and can attract the driver's attention by flashing, changing colors, etc., to improve the driver's perception of the warning information. These warning signals can quickly attract the driver's attention and make him take corresponding actions, such as slowing down, changing lanes or avoiding, to ensure road safety; the warning horn is arranged at the front and rear ends of the mobile chassis, and the volume of the warning horn can be manually adjusted according to the degree of danger of the working environment, which can enhance the warning effect, prompt emergency situations, and enhance traffic control capabilities, thereby improving road safety.

[0041] The present invention discloses a control method for a highway maintenance safety warning robot cluster, including a remote control mode and an autonomous control mode, and the control method can be flexibly switched according to different scenarios. In the remote control mode, the mobile safety warning robot can be quickly deployed, adjusted and recovered; in the autonomous mode, the safety warning robot can surround and follow the mobile working vehicle in real time within the specified range of the road, significantly reducing the labor intensity of highway maintenance operations and effectively ensuring the safety of construction workers.

[0042] Furthermore, in the autonomous control mode of the highway maintenance safety warning robot of the present invention, the control problem of the safety warning robot cluster is transformed into the trajectory tracking control problem of the leading safety warning robot and the cluster tracking control problem of the following safety warning robots. The artificial potential field theory is used to consider the safety constraints of the safety warning robot in different road environments, including the road boundary line and the position constraints of the mobile working vehicle in the lateral and longitudinal directions with the safety warning robot, so that the safety warning robot cluster can track and surround the target working vehicle in real time during the working process, while maintaining a certain formation and driving within the specified range of the road. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

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

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

[0046] Figure 3 A control mode selection flow chart of a highway maintenance operation safety warning robot cluster in the present invention;

[0047] Figure 4 It is a flow chart of a remote control mode of a highway maintenance operation safety warning robot cluster in the present invention;

[0048] Figure 5 It is a flow chart of an autonomous mode of a highway maintenance operation safety warning robot cluster in the present invention;

[0049] Figure 6 This is a diagram of a highway maintenance safety warning robot cluster working at a highway maintenance site in the present invention, wherein Figure 6 (a) is a schematic diagram of the deployment of the safety warning robot in the closed inner lane of a two-way six-lane road; Figure 6 (b) is a schematic diagram of the deployment of the curved road safety warning robot;

[0050] Figure 7 This is a schematic diagram of the structure of the spacing and angles of the safety warning robot cluster on a curved road in an embodiment of the present invention;

[0051] Figure 8 This is a simulation diagram of the operation of the pilot safety warning robot cluster moving in the closed outer lane of a straight road and a curved road with four lanes in both directions, in which Figure 8 (a) is a schematic diagram of the motion trajectory of the pilot safety warning robot cluster on a straight road; Figure 8 (b) is a schematic diagram of the motion trajectory of the pilot safety warning robot and the mobile work vehicle on a straight road; Figure 8 (c) is a schematic diagram of the motion trajectory of the pilot safety warning robot on a curved road; Figure 8 (d) is a schematic diagram of the motion trajectory of the pilot safety warning robot and the mobile working vehicle on a curved road;

[0052] Fig. 9 This is a simulation diagram of the following safety warning robot cluster moving in a closed outer lane of a two-way four-lane straight road in an embodiment of the present invention, wherein Fig. 9 (a) is a schematic diagram of the motion trajectory of the following safety warning robot cluster on a straight road; Fig. 9 (b) is the simulation result of longitudinal spacing error; Fig. 9 (c) is the simulation result of lateral spacing error;

[0053] Fig.10 This is a simulation diagram of the following safety warning robot moving in a closed outer lane of a two-way four-lane curved road in an embodiment of the present invention, wherein Fig.10 (a) is a schematic diagram of the motion trajectory of the following safety warning robot cluster on a curved road; Fig.10 (b) is the simulation result of longitudinal spacing error; Fig.10 (c) is the simulation result of lateral spacing error.

[0054] Among them: 1-ultrasonic obstacle avoidance sensor; 2-GPS positioning unit; 3-cylindrical shell; 4-depth camera; 5-reflective strip; 6-warning light; 7-warning horn; 8-driving wheel; 9-steering wheel; 10-control motor; 11-battery; 12-heat dissipation hole. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 here 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 claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0057] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

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

[0059] In addition, if the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which 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 is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

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

[0062] See also Figure 1 and Figure 2The embodiment of the present invention discloses a highway maintenance operation safety warning robot cluster, including several highway maintenance operation safety warning robots; the highway maintenance operation safety warning robot includes a mobile chassis and a warning device arranged on the mobile chassis; the warning device is provided with a depth camera 4; the mobile chassis is provided with several moving wheels, and the moving wheels are connected with a control motor 10; the mobile chassis is provided with a GPS positioning unit 2, a control unit and a power supply 11; the outer wall surface of the mobile chassis is provided with an ultrasonic obstacle avoidance sensor 1 connected with the control unit; the control motor 10, the GPS positioning unit 2 and the depth camera 4 are all connected with the control unit; the control unit signal is connected with an external remote control unit. The warning device includes a cylindrical shell 3, and a warning light 6 is arranged on the top of the cylindrical shell 3; a reflective strip 5 is arranged on the outer wall surface of the cylindrical shell 3; the control unit includes a trajectory tracking module and a cluster tracking module. A warning speaker 7 and a heat dissipation hole 12 are arranged on the outer wall surface of the mobile chassis. The moving wheel includes a driving wheel 8 and a steering wheel 9, and the driving wheel 8 and the steering wheel 9 are respectively connected with a control motor 10. The warning device includes a cylindrical shell, a depth camera and a reflective strip. The cylindrical shell 3 is arranged above the mobile chassis and is detachably connected to the mobile chassis. At the same time, a polygonal groove is arranged on the cylindrical shell 3, and a depth camera 4 is arranged in the polygonal groove. A reflective strip 5 is arranged outside 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 the power supply unit are both arranged in the mobile chassis, the drive unit is arranged under the mobile chassis, the obstacle avoidance unit is arranged at both ends of the mobile chassis, the warning unit is arranged on both sides of the obstacle avoidance unit, and the GPS positioning unit is arranged at the upper end of the mobile chassis and on both sides of the cylindrical shell. The obstacle avoidance unit adopts an ultrasonic obstacle avoidance sensor 1, which is arranged at both ends of the mobile chassis. During the autonomous movement of the safety warning robot, the ultrasonic obstacle avoidance sensor identifies the surrounding obstacles and measures the real-time distance between the safety warning robot and the obstacles, and uploads the distance between the safety warning robot and the ultrasonic obstacle avoidance sensor to the control unit. The warning unit includes a warning light 6 and a warning horn 7; the warning light 6 is arranged at the upper end of the cylindrical shell 3 and is spirally connected to the cylindrical shell 3; the warning horn 7 is arranged at the front end of the mobile chassis and is located on both sides of the ultrasonic obstacle avoidance sensor 1. The warning light 6 appears in the form of an orange or red flashing light to remind the driver to pay attention and take corresponding actions, help the driver to comply with traffic regulations, and maintain the order and safety of road traffic. The driving unit includes a driving wheel 8, a steering wheel 9 and a control motor 10; the driving wheel 8 is arranged under the mobile chassis, the steering wheel 9 is arranged on one side of the driving wheel 8, and the control motor 10 is arranged in the mobile chassis. The driving unit is used to control the driving wheel to move according to the desired speed at the current moment sent by the control unit, and to control the driving wheel to avoid obstacles according to the obstacle avoidance movement instruction.The power supply unit includes a battery 11, which is arranged at the lower end of the cylindrical shell 3 and is located in the mobile chassis. The power supply unit supplies power to the control unit, the drive unit, the positioning unit and the obstacle avoidance unit. The mobile chassis also includes a plurality of heat dissipation holes 12; the plurality of heat dissipation holes 12 are arranged outside the mobile chassis and are located on the side of the warning speaker 7 away from the ultrasonic obstacle avoidance sensor 1.

[0063] See also Figure 3 , Figure 4 and Figure 5 The present invention provides a control method for a highway maintenance operation safety warning robot cluster, comprising:

[0064] When a plurality of highway maintenance operation safety warning robots arrive at the working road, the depth camera 4 obtains boundary line and lane line information and transmits it to the control unit, and the control unit determines the working area of ​​the highway maintenance operation safety warning robot cluster; the plurality of highway maintenance operation safety warning robots include a pilot safety warning robot and the rest are follow-up mobile safety warning robots;

[0065] The control unit selects a control mode based on the working area; the control mode includes a remote control mode and an autonomous control mode; the remote control mode is specifically that an external remote control unit transmits a control signal to the control unit to control the highway maintenance operation safety warning robot cluster to move to a target position;

[0066] The autonomous control mode is specifically that the GPS positioning unit 2 and the ultrasonic obstacle avoidance sensor 1 transmit the acquired real-time information to the control unit, the control unit calculates the target position and target trajectory of the pilot safety warning robot, controls the pilot safety warning robot to move to the target position, and controls the following mobile safety warning robot to always maintain the set distance and angle with the pilot safety warning robot and move to the target position.

[0067] The following is a detailed description with reference to specific embodiments:

[0068] 1) After the safety warning robot reaches the working road, it turns on the warning light 6 and the warning horn 7; the depth camera 4 obtains the 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, during road maintenance operations, the control area should deploy safety warning robots in the order of warning area, upstream transition area, longitudinal buffer area, working area, downstream transition area and termination area. The depth camera 4 is used as a sensor of the perception system to collect expected information on the road. The depth camera sends the acquired road image information to the controller, and determines the position information of the lane dividing line based on the identified lane boundary line information. The highway is regarded as a structural road, and the lane line can be approximated as a straight line. The safe working area of ​​the safety warning robot is determined based on the lane line information under different working conditions.

[0070] 2) Select the mode according to different operation scenarios;

[0071] The safety warning robot proposed in the present invention can be applied to different operation scenarios of roads, 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, road crack treatment, etc., and mobile operations include: road cleaning, hedge maintenance, highway marking, etc.

[0072] When performing temporary operations, the remote control mode can be used to complete the deployment and recovery process of the safety warning robot. In the remote control mode, the remote control and multiple safety warning robots complete the receiver code in advance, and set different ID names on the remote control. When performing remote control, the remote control changes the ID names in turn to achieve the individual control of multiple safety warning robots. The control unit receives the speed command, steering command and braking command transmitted by the remote control to achieve real-time control of the mobile safety warning robot.

[0073] When performing mobile operations, a hybrid control mode of remote control mode and autonomous mode can be used, and the remote control mode is used to complete the initial position placement of the safety warning robot. The autonomous mode is used to complete the following of the safety warning robot during the mobile operation. In autonomous mode, the depth camera 4 automatically identifies the lane line position and the motion space, combined with GPS real-time positioning, and the information obtained by the ultrasonic obstacle avoidance sensor 1 is sent to the control unit. The control unit calculates the motion instructions of each safety warning robot at the next moment through calculation, which can ensure the safe distance between the safety warning robots to reach the destination. During the autonomous navigation process, the highway lane line can be automatically identified as the boundary of the motion space to ensure that the safety warning robot will not exceed the lane line during the movement, and the safe distance between the safety warning robots can be ensured to reach the destination. During the entire working process, the warning alarm platform is in a continuous working state to warn passing vehicles.

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

[0075] Step 1: Manually control the safety warning robot to the destination and determine whether it exceeds the lane boundary line; if so, proceed to the next step, otherwise reach the destination; Step 2: The warning light 6 changes from being always 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 the working process. Under this working condition, a single safety warning robot remote control mode is used, and manual remote control can be used to achieve rapid deployment, adjustment and recovery; and when the safety warning robot does not travel according to the planned path or does not avoid obstacles effectively in autonomous mode, it is necessary to convert the 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 of ​​the safety warning robot;

[0078] After the safety warning robot arrives at the working road, it is first deployed quickly in remote control mode, and then the depth camera 4 collects image information of the road ahead and sends it to the control unit. The control unit uses the identified lane boundary information as the boundary of the safe working area, and regards the highway as a structural road, with the lane line approximated as a straight line, to determine the safe working area of ​​the safety warning robot.

[0079] Step 2: Determine the desired position of the pilot safety warning robot;

[0080] In the present invention, the first safety warning robot in the safety warning robot cluster located in the moving direction is used as the pilot warning robot, and the remaining safety warning robots are used as follow-up warning robots. During the autonomous movement process, the pilot warning robot needs to be located in front of the mobile work vehicle and maintain a safe distance, while moving at the same speed within the specified road. Its control unit receives the road image information sent by the depth camera 4 and the precise position information of the safety warning robot and the mobile work vehicle sent by the GPS unit. At the same time, the trajectory tracking function in the control unit uses the artificial potential field theory to represent the impact of the constraint on the safety warning robot in the form of an artificial potential field and analyze its virtual force. The pilot warning robot uses the zero point of the resultant force of the virtual force as the expected position. The expected position of the pilot warning robot at the current moment can be calculated according to the following formula:

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

[0082] In the formula, F la =-k l |pL r | 2 ,

[0083]

[0084] Among them, F la F is the gravitational force of the ideal driving lane line on the navigation warning robot; bo F is the repulsive force of the road boundary line on the navigation warning robot; c To warn the pilot robot to repel the mobile working vehicle behind it; k l is the gravitational potential field constant of the lane line, p is the position vector of the pilot safety warning robot, L r is the position vector of the lane line. k b is the repulsive potential field constant of the road boundary line, d is the distance from the pilot safety warning robot to the road boundary line, and d b is the influence range of the road boundary, k s is the repulsive potential field constant of the mobile working vehicle, d s is the distance between the pilot safety warning robot and the mobile working vehicle in the longitudinal direction, d safe To ensure safe distance between the robot and the mobile work vehicle, the pilot can warn the robot of the safe distance between the robot and the mobile work vehicle.

[0085] F la The ideal driving lane line gravity of the pilot warning robot. The best position of the safety warning robot is on the road boundary line of the vehicle to guide the vehicle and improve driving safety. bo is the repulsive force of the road boundary line on the pilot warning robot. The closer the pilot warning robot is to the road boundary line, the greater the repulsive force it receives. At the next moment, the pilot warning robot will move away from the road boundary line, and the repulsive force of the road boundary line will gradually decrease. c This is the repulsive force of the mobile work vehicle behind the pilot warning robot. During the autonomous movement of the pilot warning robot, the mobile work vehicle behind is regarded as an obstacle and always maintains a safe distance from the mobile work vehicle. When the distance between the pilot safety warning robot and the mobile work vehicle is less than the safe distance, the repulsive force on the safety warning robot increases, and the next moment the pilot warning robot will gradually move away from the mobile work vehicle.

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

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

[0088]

[0089] The longitudinal expected trajectory The repulsion force F of the mobile working vehicle can bec Calculated:

[0090]

[0091] Lateral desired trajectory The ideal driving lane line gravity F la Repulsion F with road boundary line bo Calculated:

[0092]

[0093] Among them, (x0(t), y0(t)) is the position coordinate of the pilot safety warning robot at the current moment, (x c (t), y c (t)) is the position coordinate of the mobile working vehicle at the current moment; L safe is the minimum safe distance between the pilot safety warning robot and the mobile working vehicle, t a The response time of the robot for pilot safety warning.

[0094] Step 4: The safety warning robots form different graphics under different working conditions. Each robot obtains its own position information under the action of GPS. It should be noted that the position of the safety warning robot after determining the graphics is fixed;

[0095] According to the "Highway Maintenance Safety Operation Regulations", when conducting road maintenance operations, the control area should deploy safety warning robots in the order of warning area, upstream transition area, longitudinal buffer area, working area, downstream transition area and terminal area. Highways can be divided into different levels according to different usage tasks, functions and traffic conditions, and the control lengths of road maintenance operations are also different, so different numbers of safety warning robots are required. Since there are many highway maintenance operation scenarios, in order to reduce the cumbersomeness of method design and application, the present invention summarizes the 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 safety warning robot is deployed in the form of, Figure 6 As shown in (a), when maintenance work is carried out on a highway with six lanes or more, the closed lane should also close one side of the adjacent lane and arrange two upstream transition zones. At the same time, the minimum spacing between the two upstream transition zones should be greater than 200 meters. For maintenance work on curved roads, the safety warning robot is deployed in a 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 work, the starting point of the warning zone should be arranged 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: According to the final encirclement pattern, each following warning robot maintains a certain distance and angle with the leading warning robot, drives towards the final destination, and determines whether it exceeds the lane boundary line. If so, it proceeds to the next step, otherwise it reaches the destination.

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

[0098]

[0099] In the formula,

[0100]

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

[0102] (x i ,y i ) is the position of the i-th safety warning robot in the inertial coordinate system, is the expected longitudinal spacing of the ith safety warning robot, is the expected lateral spacing of the i-th safety warning robot. At the same time, in order to make the lateral and longitudinal spacing errors of the safety warning robot approach zero during movement, an artificial potential field function G is added. iT , represents the spacing error q of the i-th safety warning robot i The expected distance error q with the expected tracking arrival 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 is i The distance error q with the jth 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 at the next moment will make the i-th warning robot and the j-th warning robot approach each other.

[0104] expression Represents the repulsive field. When the distance error q of the i-th following warning robot i The distance error q with the jth 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 make the i-th warning robot and the j-th warning robot move away from each other.

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

[0106] Step 6: The warning light 6 changes from being always on to flashing;

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

[0108] In order to verify the correctness and effectiveness of the trajectory tracking control of the pilot safety warning robot in the designed autonomous mode, the trajectory tracking system is numerically simulated based on Matlab simulation software. The operation scene is the maintenance operation of the mobile operation vehicle on the straight and curved lanes of the closed outer lanes of the two-way four-lane. The ode45 function is used to verify the trajectory tracking control algorithm. The dynamic parameters of the pilot safety warning robot in the simulation are: the mass of the safety warning robot m = 3.5kg; the distance from the geometric center of the warning robot to the center of mass d = 0.1m along the x-axis direction; the moment of inertia I = 3 (kg·m 2 );The distance from the warning robot driving wheel to the symmetry axis is R=0.23m;The driving wheel radius is r=0.036m;The given initial conditions are:

[0109] x0(0)=10, y0(0)=0.1, θ0(0)=3°;

[0110]

[0111] Working condition 1: Maintenance work on the outer lanes of a four-lane, two-way straight road;

[0112] Take L ref =0,d bo =0.2,La =10,t a =3; Consider the movement of the mobile vehicle during the actual operation: the speed of the mobile vehicle is 4km / h = 1.11m / s, and the starting acceleration is 1.310m / s 2 , the motion equation of the designed mobile working vehicle is:

[0113]

[0114] Working condition 2: Maintenance work on the outer lane of a four-lane two-way curved road:

[0115] Considering that the mobile vehicle will slow down during the curve operation, the safe distance d between the mobile vehicle and the pilot safety warning robot is safe Ignoring the speed of the mobile vehicle, take d safe =L safe , and fix the safety distance L safe is the arc length, and the motion equation of the mobile working vehicle is designed as:

[0116]

[0117] The simulation results of trajectory tracking control of the pilot safety warning robot are as follows Figure 8 As shown, it can be seen from the simulation results that the pilot safety warning robot can track the desired trajectory very well. At the same time, the pilot 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 pilot safety warning robot designed in the present invention.

[0118] At the same time, in order to verify the correctness and effectiveness of the designed tracking control of the safety warning robot cluster in the autonomous mode, the safety warning robot cluster tracking controller is numerically simulated under straight road and curved road conditions based on Matlab simulation software. The ode45 function is used in Matlab simulation software to perform numerical simulations on the safety warning robot cluster tracking control in straight roads and curved roads. Due to the large number of safety warning robots in actual use, 14 safety warning robots on straight roads and 4 safety warning robots on curved roads are used as examples for simulation verification. The main dynamic parameters of the safety warning robots on straight roads and curved roads are as follows.

[0119] Working condition 1: Maintenance work on the outer lanes of a four-lane, two-way straight road;

[0120] The simulation parameters are: 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 pilot safety warning robot is: x0 = 15, y0 = 0, θ0 = 0°, x0(t) = 15 + 0.02t 2 , y0(t)=0, the initial speeds of the other 13 following safety warning robots are all 0, and their initial postures are shown in the following table:

[0121]

[0122] Working condition 2: Maintenance work on the outer lane of a four-lane two-way curved road;

[0123] The simulation parameters are: 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] The simulation results of cluster tracking control following the safety warning robot are as follows Fig. 9 , 10 As shown, Fig. 9 (a) Fig.10 (a) The motion trajectory diagrams of the safety warning robots on straight roads and curved roads respectively. It can be seen from the figure that when operating in different road environments, the safety warning robot cluster eventually forms the desired formation; Fig. 9 (b), 9(c), 10(b) and 10(c), it can be seen that the lateral spacing error and the longitudinal spacing error of the safety warning robot tend to zero during autonomous movement, which verifies the correctness and effectiveness of the designed cluster tracking control.

[0125] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A highway maintenance operation safety warning robot cluster, characterized in that: The invention comprises a plurality of highway maintenance operation safety warning robots; the highway maintenance operation safety warning robots comprise a mobile chassis and a warning device arranged on the mobile chassis; the warning device is provided with a depth camera (4); the mobile chassis is provided with a plurality of moving wheels, and the moving wheels are connected to a control motor (10); the mobile chassis is provided with a GPS positioning unit (2), a control unit and a power supply (11); an ultrasonic obstacle avoidance sensor (1) connected to the control unit is provided on the outer wall surface of the mobile chassis; the control motor (10), the GPS positioning unit (2) and the depth camera (4) are all connected to the control unit; and the control unit signal is connected to an external remote control unit.

2. The highway maintenance operation safety warning robot cluster according to claim 1 is characterized in that: The warning device comprises a cylindrical shell (3), a warning light (6) being arranged on the top of the cylindrical shell (3); a reflective strip (5) being arranged on the outer wall surface of the cylindrical shell (3); and the control unit comprises a trajectory tracking module and a cluster tracking module.

3. The highway maintenance operation safety warning robot cluster according to claim 1 is characterized in that: A warning horn (7) and heat dissipation holes (12) are arranged on the outer wall surface of the mobile chassis.

4. The highway maintenance operation safety warning robot cluster according to claim 1, characterized in that: The moving wheel comprises a driving wheel (8) and a steering wheel (9), and the driving wheel (8) and the steering wheel (9) are respectively connected to a control motor (10).

5. A control method for a highway maintenance operation safety warning robot cluster according to any one of claims 1 to 4, characterized in that: include: When a plurality of highway maintenance operation safety warning robots arrive at the working road, the depth camera (4) acquires boundary line and lane line information and transmits it to a control unit, and the control unit determines the working area of ​​the highway maintenance operation safety warning robot cluster; the plurality of highway maintenance operation safety warning robots include a pilot safety warning robot and the rest are follower mobile safety warning robots; The control unit selects a control mode based on the working area; the control mode includes a remote control mode and an autonomous control mode; the remote control mode is specifically that an external remote control unit transmits a control signal to the control unit to control the highway maintenance operation safety warning robot cluster to move to a target position; The autonomous control mode specifically comprises the following steps: the GPS positioning unit (2) and the ultrasonic obstacle avoidance sensor (1) transmit the acquired real-time information to the control unit; the control unit calculates the target position and target trajectory of the pilot safety warning robot, controls the pilot safety warning robot to move to the target position, and controls the following mobile safety warning robot to always maintain a set distance and angle with the pilot safety warning robot and move to the target position.

6. The control method of the highway maintenance operation safety warning robot cluster according to claim 5 is characterized in that: The control unit calculates the target position and target trajectory of the pilot safety warning robot, and controls the pilot safety warning robot to move to the target position specifically as follows: The control unit constructs the driving lane line potential field, boundary line potential field and mobile work vehicle potential field of the pilot safety warning robot through the artificial potential field theory. During the autonomous movement of the pilot safety warning robot, the driving lane line attraction, road boundary line repulsion and mobile work vehicle repulsion generated by the artificial potential field are exerted; the control unit takes the position where the virtual force exerted on the pilot safety warning robot is zero as its target position, so that the pilot safety warning robot always drives within the specified range and maintains a certain safe distance from the mobile work vehicle during the movement in the autonomous control mode; the virtual force exerted on the pilot safety warning robot is expressed as follows: F=F la +F bo +F c (1) F la =-k l |p-L r | 2 (2) Among them, F la The ideal driving lane line gravity for the pilot safety warning robot. The best position of the safety warning robot is on the road boundary line of the vehicle to guide the vehicle and improve driving safety. bo F is the repulsive force of the road boundary line on the navigation safety warning robot; c To warn the robot of the repulsion of the mobile working vehicle behind it for safety; k l is the gravitational potential field constant of the lane line; p is the position vector of the pilot safety warning robot; L r is the position vector of the lane line; k b is the repulsive potential field constant of the road boundary line; d is the distance from the pilot safety warning robot to the road boundary line; d b is the influence range of the road boundary; k s is the repulsive potential field constant of the mobile working vehicle; d s The distance between the navigation safety warning robot and the mobile working vehicle in the longitudinal direction; d safe To ensure safe distance between the robot and the mobile work vehicle, the pilot can warn the robot of the safe distance between the robot and the mobile work vehicle.

7. The control method of the highway maintenance operation safety warning robot cluster according to claim 6 is characterized in that: The target trajectory of the pilot safety warning robot is calculated as follows: The target trajectory is divided into the moving operation direction and the vertical direction of the moving operation direction for calculation, and the expression is as follows: in, The target trajectory of the moving operation direction; It is the target trajectory perpendicular to the moving operation direction.

8. The control method of the highway maintenance operation safety warning robot cluster according to claim 7 is characterized in that: The calculation of the target trajectory of the moving operation direction is: According to the artificial potential field theory, in the moving operation direction, the pilot safety warning robot is subjected to the repulsive force generated by the potential field of the mobile operation vehicle behind it during its autonomous movement, and its moving operation direction target trajectory Repulsion F with mobile working vehicle c When the distance between the pilot safety warning robot and the mobile working vehicle changes, the repulsive force F c When it changes, the target trajectory of the moving operation direction will also change to ensure the safe distance between the pilot safety warning robot and the mobile operation vehicle. The target trajectory of the moving operation direction is calculated by the following expression: Among them, (x0(t), y0(t)) is the position coordinate of the pilot safety warning robot at the current moment, (x c (t), y c (t)) is the position coordinate of the mobile working vehicle at the current moment; L safe is the minimum safe distance between the pilot safety warning robot and the mobile working vehicle, t a The response time of the robot for pilot safety warning.

9. The control method of the highway maintenance operation safety warning robot cluster according to claim 8, characterized in that: The calculation of the target trajectory perpendicular to the moving operation direction is: In the process of autonomous movement, the pilot safety warning robot is affected by the gravitational force of the ideal driving lane line and the repulsive force of the road boundary line in the direction perpendicular to the moving operation direction, and moves perpendicular to the target trajectory in the moving operation direction. The gravitational force F of the ideal driving lane line la Repulsion F with road boundary line bo When the pilot safety warning robot deviates from the ideal driving lane line during driving, the gravitational force of the ideal driving lane line and the repulsive force of the road boundary line change, and the target trajectory perpendicular to the moving operation direction calculated at the next moment will also change accordingly, so that the pilot safety warning robot can drive on the ideal lane line and the lateral desired trajectory It is calculated by the following expression:

10. The control method of the highway maintenance operation safety warning robot cluster according to claim 9, characterized in that: Controlling the following mobile safety warning robot and the pilot safety warning robot to always maintain a set distance and angle specifically includes: According to the artificial cluster theory, the control unit takes the lateral spacing error and the longitudinal spacing error between two adjacent following safety warning robots as the state variables of the cluster system, and constructs the cluster kinematic equation, so that the following safety warning robots surround the mobile working vehicle in a certain formation during the autonomous movement and follow the leading safety warning robot to move to the target position. The cluster kinematic expression is as follows: Among them, q i ∈R n is the state variable, G ij (·):R n ×R n →R represents the potential field formed by the safety warning robots i and j. The influence of each safety warning robot on the safety warning robot i is accumulated and acts on the mobile safety warning robot j. At the same time, in order to make the horizontal and vertical spacing errors of the safety warning robots approach zero during movement, an artificial potential field function G is added. iT , represents the spacing error q of the i-th safety warning robot i The expected distance error q with the expected tracking arrival T potential field function; a represents the gravitational field. At the current moment, if the spacing error q of the i-th following warning robot i The distance error q with the jth 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 speed at the next moment will make the i-th safety warning robot and the j-th safety warning robot approach each other; the expression is Represents the repulsive field. At the current moment, if the distance error q of the i-th following warning robot i The distance error q with the jth 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 at the next moment will make the i-th safety warning robot and the j-th safety warning robot move away from each other.

Images