Research On Environment Perception And Tracking Control Of Forest Mobile Robots

The application of forest mobile robots can solve the problems of low efficiency and high labor costs in forest operations,and lay the foundation for the development of intelligent forestry.In order to realize the autonomous movement of mobile robots in forest and improve the intelligence of forest operations,this study has carried out research on the environment perception and tracking control of forest mobile robots.First,a platform for a forest mobile robot is built,and then the platform is used to detect forest road.Finally,the road information is transferred to the robot tracking control module to realize the autonomous movement for the robot.The main research content,methods and results of this study are as follows:(1)Construction of forest mobile robot platform.First,the Ackerman mobile robot,two-dimensional(2D)Li DAR and monocular camera are selected to form the hardware system.And each module communicates under ROS to build a software platform.Then the camera is calibrated by Zhang’s calibration method,the adaptive algorithm is used to synchronize the data captured by 2D Li DAR and camera in time,and the nonlinear least square method is employed to solve and optimize the external parameters.(2)Environment perception of forest mobile robot.This paper mainly studies the road detection part of the forest mobile robot environment perception module.A forest road detection method based on 2D Li DAR and monocular camera is proposed.This method first uses straight-through filtering to remove the useless information in the road point cloud,and then performs curve fitting to obtain the boundary of the passable area.At the same time,this method first uses superpixel segmentation to divide the road image into several sub-regions,and then uses SVM to classify each sub-region to obtain the road area.Then the road boundary is solved by Canny algorithm,curve fitting,etc.Finally,the point cloud and image information are combined to obtain road parameters.(3)Tracking control of forest mobile robot.First,the kinematics model of the forest mobile robot is analyzed and established.Then this paper analyzes and studies the mobile robot tracking control method based on the model prediction algorithm.And the simulation of the straight-line and circular trajectory is carried out to verify its effect.The results show that the algorithm can make the robot find the reference trajectory accurately and drive along it stably.(4)Experimental verification.First,four groups of forest road data are collected to verify and analyze the road detection method proposed in this paper.The results show that the method can obtain the road boundary,road width and center navigation line more accurately.Then the reference trajectory of the robot is manually given indoors,and the real trajectory of the robot is recorded for analysis.The result shows that the error is within 0.30 m.Finally,the vehicle tracking control experiment is carried out in the forest,and the result shows that the error is within 0.50 m after the system is stable.