Robot navigation method with strict path following

Abstract

The invention relates to a robot navigation method with a strict path following function, and belongs to the technical field of inspection robot navigation, the implementation of a robot inspection process is mainly divided into two steps of deployment and operation: in the deployment process, firstly marking point locations on a map, then connecting the point locations through a mobile phone APP to draw inspection paths, and combining the inspection paths; forming an inspection task; in the operation process, the robot receives an inspection task issued by the mobile phone APP or the upper computer, the navigation program analyzes the task and calls the global planner and the local planner to generate a global path and a local path, and meanwhile, a speed control instruction for controlling the robot to move is generated. Wherein the global path is completely the same as the path pre-drawn through the mobile phone APP, and the local path strictly follows the global path. According to the method, the inspection robot can advance strictly according to the preset path, and the working safety and efficiency of the robot in the special environment can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of robot navigation, and in particular to a robot navigation method for strictly following a path. Background Art

[0002] In special environments such as coal mines, petroleum, chemical industry and nuclear radiation, traditional manual inspection methods have many disadvantages. On the one hand, its efficiency is extremely low; on the other hand, workers conducting inspections in such environments are very likely to cause irreversible and serious damage to their health. The popularization and application of intelligent inspection robots is undoubtedly the key to solving this problem.

[0003] The ability to strictly follow a preset path is an important function of an inspection robot. However, most public solutions use a method of autonomously generating navigation paths based on grid maps, which may cause a series of problems in practical applications. First, the robot's autonomous generation of navigation paths may expose it to unknown or high-risk areas, thereby greatly increasing the probability of failure or loss of control. In special environments, once a robot fails or loses control, it may not only affect the normal progress of the inspection work, but also bring other safety hazards. Second, inspection work in special environments usually needs to be carried out continuously and uninterruptedly. If the robot generates a path autonomously, it is likely that some areas will be repeatedly checked while other areas will be missed, which will undoubtedly reduce the efficiency and accuracy of the inspection and fail to give full play to the role that the inspection robot should play. Therefore, in special environments, how to better utilize the inspection robot and improve the accuracy and reliability of its path planning is an urgent problem to be solved.

[0004] Therefore, in order to ensure that the inspection robot works safely and efficiently in special environments, it is necessary to design a robot navigation method that strictly follows the path (i.e., strict line patrol). Strict line patrol means that the robot always travels on a known and relatively safe path, greatly reducing the safety risks caused by improper path selection. At the same time, strict line patrol ensures that each inspection can be performed according to the established time interval and path, avoiding unnecessary duplication and omissions. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned technology, the present invention provides a robot navigation method with strict path following, so that the inspection robot moves strictly according to the preset path, thereby improving the safety and efficiency of the robot working in special environments.

[0006] The present invention provides a robot navigation method for strictly following a path, and the technical solution is as follows: the navigation method includes robot deployment and robot operation; The robot deployment includes the following steps: Step 1.1 Create points and mark them on the map. The created points include waypoints, navigation points and charging points. Step 1.2: Draw an inspection path, connect the points created in step 1.1, and form a complete inspection path; The robot operation includes the following steps: Step 2.1 Receiving and parsing the task instructions. During the robot's task execution, the robot's industrial computer is responsible for receiving the task instructions and parsing them. Then the global planner is called, and the global planner generates a global path based on the received parsed task instruction information. The parsed task instruction information includes the target point, path curvature, and travel direction information. Step 2.2: Local path planning and control command sending: Call the local planner, which calculates the local path based on the global path, the distance between the robot and the obstacle, and the current motion state of the robot, and sends the corresponding speed control command to the robot chassis; Step 2.3 Inspection target detection: After the robot reaches the designated inspection point, it starts the target detection program to identify the established target; after completing the inspection of a point, the robot will continue to the next stage of the task; Repeat steps 2.1-2.3 until the robot completes the entire inspection task.

[0007] Furthermore, the creation of points in step 1.1 refers to determining the precise position of the robot in the map through multi-sensor fusion technology during the deployment process; the waypoints are used to regulate the robot's route to ensure that the robot travels along the predetermined trajectory; the navigation points are used to instruct the robot to identify specific targets; the charging points are used as the location where the robot docks with the charging pile for automatic charging; the point information of the created points is recorded and stored in a json file.

[0008] Furthermore, in step 1.2, the direction and curvature of the inspection path also need to be configured; if there are multiple inspection paths, the inspection paths need to be combined, and the combined inspection path is to combine multiple inspection paths together in a combined manner.

[0009] Furthermore, in step 2.1, before the robot performs the task, it must first determine whether the robot is already at the starting point of the inspection task: if the robot is not at the inspection starting point, it uses the autonomous navigation function to move to the starting point by itself. When the robot reaches the starting point of the inspection task, it switches to the path following mode and starts to perform the inspection task; if the robot is already at the starting point, it can directly enter the path following mode to start performing the inspection task.

[0010] Furthermore, the inspection path consists of a straight line and an arc with a specific curvature. If the curvature is 0, the robot moves along a straight line; if the curvature is not 0, the robot moves along an arc with a certain curvature.

[0011] Furthermore, in step 2.1, the global planner generates a series of points between the starting point and the end point of the inspection path by interpolation to form a global path. The calculation method of the global path is as follows: (1) Calculate the number of interpolation points required between two path points: num_wpts=dis ppm The number of interpolation points between two path points is num_wpts+1, which will be rounded down during the calculation process. dis is the Euclidean distance between two path points, and ppm is the number of interpolation points per meter. (2) Calculate the pose information of the interpolation point: If the curvature is 0, the global planner generates a global path directly by linear interpolation based on the number of interpolation points: ; Among them, (x i ,y i ,yaw) is the position of the interpolation point on the straight path, x i ,y i and yaw represent the horizontal coordinate, vertical coordinate and yaw angle of the interpolation point on the straight path in the map coordinate system, respectively. 0 and 0 They represent the horizontal and vertical coordinates of the starting point of the straight path in the map coordinate system, respectively. 1 and 1 Respectively represent the horizontal and vertical coordinates of the end point of the straight line path in the map coordinate system; if the inspection path is configured to retreat, then .

[0012] Furthermore, step (2) calculates the pose information of the interpolation point: If the curvature is not 0, the global planner will generate an arc path based on the curvature and path point information. The calculation method of the arc path is as follows: ①Calculate the arc radius based on the curvature: R=1 / C Among them, R represents the radius of the arc, and C represents the curvature of the arc; ② Calculate the center position of the circle. The calculation process is as follows: ; Among them, x 1 and 1 Respectively represent the horizontal coordinate and vertical coordinate of the starting point of the arc path in the map coordinate system, x 2 and2 They represent the horizontal and vertical coordinates of the arc path end point in the map coordinate system respectively;

[0013]

[0014] in, is the coordinate of the center of the circle; ③Calculate the position and posture of the interpolation point on the arc: ; in, is the position and posture of the interpolation point on the arc path, , and Respectively represent the horizontal coordinate, vertical coordinate and yaw angle of the interpolation point on the arc path in the map coordinate system; if the inspection path direction is configured as backward, then .

[0015] Furthermore, the current motion state of the robot in step 2.2 includes the position, velocity, and acceleration of the robot.

[0016] Furthermore, in step 2.3, if the robot completes the inspection task, it returns to the charging point for charging.

[0017] The beneficial effects of the present invention are as follows: the present invention uses a preset path instead of an autonomously generated path, which greatly improves the safety and stability of the inspection robot during its operation; at the same time, strict line inspection ensures the completion time of the inspection task and improves the inspection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A flowchart of the robot navigation method; Figure 2 Generate a schematic diagram for the inspection robot's path. DETAILED DESCRIPTION

[0019] The technical scheme in the embodiment of the present invention is described clearly and completely below in conjunction with the accompanying drawings in the embodiment of the present invention. In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0020] The following is a further description of a robot navigation method for strictly following a path proposed by the present invention. The robot needs to have hardware equipment such as laser radar, inertial measurement unit (IMU), encoder, industrial computer, etc. to achieve high-precision positioning and navigation. All software programs run based on the ROS framework. The robot first obtains its position in the map through multi-sensor fusion, and marks the point information through the mobile phone APP, and then connects each point in turn to form a preset navigation path. The robot will strictly follow the preset path during the inspection process. The above robot will be deployed and operated according to the following steps. Example 1

[0021] Combination Figure 1 and Figure 2 As shown, the navigation method includes robot deployment and robot operation; 1. The robot deployment includes the following steps: Step 1.1 Create points. During the deployment process, the precise position of the robot in the map is determined through multi-sensor fusion technology. The specific method is to drive the robot to the designated location and record the position information of the robot in the map at this time through the mobile phone APP. This process is completed by reading the transformation relationship (TF) between the robot chassis and the map coordinate system. The created points are divided into three categories: waypoints, navigation points and charging points. Waypoints are used to regulate the robot's route to ensure that it travels along the predetermined trajectory; navigation points are used to instruct the robot to identify specific targets; charging points are the location where the robot docks with the charging pile for automatic charging. Here, the robot will temporarily turn off the obstacle avoidance function. The point information is recorded and stored in a json file for subsequent use; Step 1.2 Draw the inspection path, and connect the points created in the previous step through the mobile phone APP to form a complete inspection path. In this process, you also need to configure the robot's travel direction and path curvature to achieve the desired movement effect; the travel direction mainly determines whether the robot moves forward or backward, and the path curvature is used to determine the degree of bending of the robot when turning.

[0022] It also includes combined inspection paths. If multiple path tasks need to be executed at the same time, multiple inspection paths can be combined together. The purpose of this is to be more flexible when configuring inspection tasks, and the inspection order and scope can be adjusted according to actual needs.

[0023] 2. The robot operation includes the following steps: Step 2.1 Receiving and parsing task instructions, Before the robot starts to perform a task, it must first determine whether it is already at the starting point of the inspection task. If not, the robot will use the autonomous navigation function to move to the starting point by itself; once it reaches the starting point, the robot can switch to path following mode and start to perform the inspection task. If the robot is already at the starting point, it can directly enter path following mode; During the robot's mission, the industrial computer is responsible for receiving and parsing the mission instructions issued by the host computer or mobile phone APP; the parsed instructions include key information such as the target point, path curvature and direction of travel, which will be sent to the global planner in a specific data format (usually called a "topic"). The target point is the next point on the inspection path that the robot needs to drive to. The global planner will then generate a global path that is completely consistent with the path pre-planned through the mobile phone APP based on this information and the robot's current position (that is, the starting point, usually the target point in the previous driving cycle corresponding to the target point of the current driving cycle). The global path is the path for the robot to drive from the current position to the target point and perform the inspection task.

[0024] The inspection route consists of straight lines and arcs with specific curvature (arcs are circular paths, which refer to the non-straight parts of the inspection route, commonly known as the route when turning). If the curvature is 0, the robot moves along a straight line; if it is not 0, the robot moves along an arc with a certain curvature. The global planner generates a series of points between the starting point and the end point to form a global path through interpolation. The global path is calculated as follows (the following global path includes straight line paths and arc paths, based on the starting point and the middle point (x 1 and 1 ) plans a straight line path and based on the intermediate and end points (x 2 and 2 ) Plan the arc path, the straight line path and the arc path are combined to form the global path): (1) Calculate the number of interpolation points required between two path points: num_wpts=dis ppm Among them, the number of interpolation points between two path points is num_wpts+1, which will be rounded down during the calculation process, dis is the Euclidean distance between the two path points, and ppm is the number of interpolation points per meter (this value is set in advance in the program, and the interpolation points include two path points); (2) Calculate the pose information of the interpolation point: If the curvature is 0, the global planner directly generates the straight path part of the global path by linear interpolation according to the number of interpolation points (the global path here is the global path between two marked points, and the curvature is 0, which indicates the straight path part of the global path): ; Among them, (x i ,y i ,yaw) is the pose of the interpolation point, x i ,y i and yaw represent the horizontal coordinate, vertical coordinate and yaw angle of the interpolation point on the straight path in the map coordinate system, respectively. 0 and 0 They represent the horizontal and vertical coordinates of the starting point of the straight path in the map coordinate system, respectively. 1 and 1 Respectively represent the horizontal and vertical coordinates (i.e. the coordinates of the middle point) of the end point of the straight path in the map coordinate system; if the inspection path is configured to retreat (when the target point is behind the current position, the robot retreats directly instead of turning around), then .

[0025] If the curvature is not 0 (i.e. the arc path part of the global path), the global planner will generate an arc path based on the curvature and path point information. The calculation method of the arc path is as follows: ①Calculate the arc radius based on the curvature: R=1 / C Among them, R represents the radius of the arc, and C represents the curvature of the arc; ② Calculate the center position of the circle. The calculation process is as follows: ;

[0026] Among them, x 1 and 1 Respectively represent the horizontal coordinate and vertical coordinate of the starting point of the arc path in the map coordinate system (that is, the horizontal coordinate and vertical coordinate of the end point of the straight path connected to the starting point of the arc path in the map coordinate system, that is, an intermediate point of the global path), x 2 and 2 They respectively represent the horizontal coordinate and vertical coordinate of the end point of the arc path in the map coordinate system (that is, the end point of the global path including the straight path and the arc path); ; in, is the coordinate of the center of the circle; ③Calculate the position and posture of the interpolation point on the arc: ; in, is the position and posture of the interpolation point on the arc path, , and Respectively represent the horizontal coordinate, vertical coordinate and yaw angle of the interpolation point on the arc path in the map coordinate system; if the inspection path direction is configured as backward, then .

[0027] Step 2.2 Local path planning and control command sending, the navigation program calls the local planner, the local planner calculates the local path based on the global path generated in step 2.1, the current motion state of the robot (including position, speed, acceleration, etc.) and the obstacle information in the surrounding environment perceived in real time by the lidar (the local path is not the path between two interpolation points, but the path generated by the algorithm program according to the global path, the current motion state of the robot and the obstacle information in the surrounding environment, which changes in real time), and optimizes the local path through the TEB (Time Elastic Band) algorithm to generate an optimal local path that meets the global path constraints and avoids obstacles, and sends the corresponding speed control command to the robot chassis. This process ensures that the robot can accurately move along the preset path and avoid collisions with obstacles. During the movement of the robot, the surrounding environment information will be detected in real time through its own sensors. If an obstacle is encountered, the robot will stop and will not continue to move forward until the obstacle is removed. At the same time, the robot will compare the current posture and the posture of the target navigation point in real time to see if they meet the preset tolerance range (the tolerance range refers to the difference between the actual posture of the robot when it reaches the target point and the expected posture, including the horizontal coordinate, vertical coordinate and yaw angle; it is mainly judged by calculating the absolute value of the difference between the actual posture and the expected posture. When the horizontal coordinate, vertical coordinate and yaw angle all meet the preset tolerance range, the robot is considered to have reached the target point). If it meets the tolerance range, the robot stops moving and performs the target recognition task; if it does not meet the tolerance range, the robot continues to move forward; Step 2.3 Inspection target detection: After the robot reaches the designated inspection point, it starts the target detection program to identify the established target; after completing the inspection of a point, the robot will continue to the next stage of the task; Finally, the robot will monitor the entire inspection process to determine whether the inspection task has been completed. If it is completed, the robot will return to the charging point for charging; if it is not completed, it will continue to repeat steps 2.1-2.3 until the robot completes the entire inspection task. Example 2

[0028] Based on Example 1, if the global path only includes straight line paths and no arc paths, then based on the starting point and the end point (x 2 and 2) Plan a straight path as the global path. The number of interpolation points of the straight path is calculated according to "(1) Calculating the number of interpolation points required between two path points" in Example 1; the position information of the interpolation points is calculated according to the calculation formula generated for the straight path part when the curvature is 0 in "(2) Calculating the position information of the interpolation points" in Example 1, and only the x in this part of the formula in Example 1 is replaced by 1 and 1 Modify to x 2 and 2 , that is, changed to the end point coordinates of the global path. Example 3

[0029] On the basis of Example 2, if the global path includes a straight path-arc path-straight path, the straight path-arc path is generated in accordance with Example 1, and the remaining straight path is generated with the end point of the arc path as the starting point in accordance with Example 2. When the global path includes multiple straight paths and multiple arc paths, the global path is generated by referring to the above embodiments of the present application.

[0030] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A robot navigation method with strict path following, characterized in that: The navigation method includes robot deployment and robot operation; The robot deployment includes the following steps: Step 1.1 Create points and mark them on the map. The created points include waypoints, navigation points and charging points. Step 1.2: Draw an inspection path, connect the points created in step 1.1, and form a complete inspection path; The robot operation includes the following steps: Step 2.1 Receiving and parsing the task instructions. During the robot's task execution, the robot's industrial computer is responsible for receiving the task instructions and parsing them. Then the global planner is called, and the global planner generates a global path based on the received parsed task instruction information. The parsed task instruction information includes the target point, path curvature, and travel direction information. Step 2.2: Local path planning and control command sending: Call the local planner, which calculates the local path based on the global path, the distance between the robot and the obstacle, and the current motion state of the robot, and sends the corresponding speed control command to the robot chassis; Step 2.3 Inspection target detection: After the robot reaches the designated inspection point, it starts the target detection program to identify the established target; after completing the inspection of a point, the robot will continue to the next stage of the task; Repeat steps 2.1-2.3 until the robot completes the entire inspection task.

2. A robot navigation method with strict path following according to claim 1, characterized in that: Creating points in step 1.1 means determining the precise position of the robot in the map through multi-sensor fusion technology during the robot deployment process; the waypoints are used to regulate the robot's route to ensure that the robot travels along the predetermined trajectory; the navigation points are used to instruct the robot to identify specific targets; the charging points are used as the locations where the robot docks with the charging pile for automatic charging; the point information of the created points is recorded and stored in a json file.

3. A robot navigation method with strict path following according to claim 1, characterized in that: In step 1.2, the direction and curvature of the inspection path also need to be configured; if there are multiple inspection paths, the inspection paths need to be combined, and the combined inspection path is to merge multiple inspection paths together by combining.

4. A robot navigation method with strict path following according to claim 1, characterized in that: Step 2.1 Before the robot performs a task, it must first determine whether it is already at the starting point of the inspection task: if the robot is not at the inspection starting point, it will use the autonomous navigation function to move to the starting point by itself. When the robot reaches the starting point of the inspection task, it will switch to the path following mode and start to perform the inspection task; If the robot is already at the starting point, it can directly enter the path following mode to start the inspection task.

5. The robot navigation method of strict path following according to claim 1, characterized in that: The inspection path consists of a straight line and an arc with a specific curvature. If the curvature is 0, the robot moves along a straight line; if the curvature is not 0, the robot moves along an arc with a certain curvature.

6. A robot navigation method for strict path following according to claim 5, characterized in that: In step 2.1, the global planner generates a series of points between the start and end points of the inspection path by interpolation to form a global path. The calculation method of the global path is as follows: (1) Calculate the number of interpolation points required between two path points: num_wpts=dis ppm The number of interpolation points between two path points is num_wpts+1, which will be rounded down during the calculation process. dis is the Euclidean distance between two path points, and ppm is the number of interpolation points per meter. (2) Calculate the pose information of the interpolation point: If the curvature is 0, the global planner generates a global path directly by linear interpolation based on the number of interpolation points: ； Among them, (x i ,y i ,yaw) is the position of the interpolation point on the straight path, x i ,y i and yaw represent the horizontal coordinate, vertical coordinate and yaw angle of the interpolation point on the straight path in the map coordinate system, x0 and y0 represent the horizontal coordinate and vertical coordinate of the starting point of the straight path in the map coordinate system, x1 and y1 represent the horizontal coordinate and vertical coordinate of the end point of the straight path in the map coordinate system; if the inspection path is configured to retreat, then .

7. A robot navigation method with strict path following according to claim 6, characterized in that: Step (2) Calculate the pose information of the interpolation point: If the curvature is not 0, the global planner will generate an arc path based on the curvature and path point information. The calculation method of the arc path is as follows: ①Calculate the arc radius based on the curvature: R=1 / C Among them, R represents the radius of the arc, and C represents the curvature of the arc; ② Calculate the center position of the circle. The calculation process is as follows: ； Among them, x1 and y1 represent the horizontal coordinate and vertical coordinate of the starting point of the arc path in the map coordinate system, respectively, and x2 and y2 represent the horizontal coordinate and vertical coordinate of the ending point of the arc path in the map coordinate system, respectively; ； in, is the coordinate of the center of the circle; ③Calculate the position and posture of the interpolation point on the arc: ； in, is the position and posture of the interpolation point on the arc path, , and Respectively represent the horizontal coordinate, vertical coordinate and yaw angle of the interpolation point on the arc path in the map coordinate system; if the inspection path direction is configured as backward, then .

8. The robot navigation method with strict path following according to claim 1, characterized in that: The current motion state of the robot in step 2.2 includes the position, velocity, and acceleration of the robot.

9. A robot navigation method for strict path following according to claim 1, characterized in that: In step 2.3, if the robot completes the inspection task, it returns to the charging point for charging.

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