Research On Track Tracking Control Of Agricultural Wheeled Mobile Robot

With the acceleration of the process of agricultural intellectualization in China,agricultural wheeled mobile robots are applied more and more widely.Agricultural robots liberate a large number of agricultural labor force,improve the level of agricultural production,and improve the living standards of the people.Trajectory tracking control is one of the most important issues in the field of robotics.This thesis mainly focuses on its trajectory tracking and automatic path recognition in the ridges of farmland.The main research results are as follows:In the first part,on the basis of kinematics,aiming at the problem of longitudinal sliding in kinematics model,this thesis establishes an adaptive trajectory tracking strategy,and verifies the stability of the system under the control law by constructing Lyapunov function,and validates the effectiveness of the control algorithm through straight and circular trajectory tracking curves.Secondly,aiming at the problem of trajectory tracking control of kinematics and dynamics model under pure rolling without sliding model,this thesis introduces the input of velocity-assisted control,constructs dynamic adaptive sliding mode control law and parameter adaptive law,realizes the desired trajectory tracking of agricultural wheeled mobile robot,and meets the requirements of trajectory tracking.In the second part,based on the navigation tracking problem of vision path of agricultural wheeled mobile robot,the gray-scale processing of the collected crop images is used to reduce the influence of illumination on image segmentation.The gray-scale image is segmented by the mixed threshold method,The feature value of the image is extracted and divided into different blocks,which reduces the useless information.Then,the straight line data is extracted by the segmented projection method to speed up straightening.At last,the method of offset midline is used to divide the crop rows,which can improve the recognition rate of the path.Finally,on the basis of the above theory and simulation,the hardware control platform and image processing hardware platform of agricultural wheeled mobile robot are designed with ARM processor as the control core.The software program is written in Keil5,the development environment of ARM,and the control system is realized.There are 62 thesis,1 table and 72 references in this thesis.