Research On Localization And Mapping Of Substation Inspection Robot Based On 3D Lidar

With the extension of unattended substation,nowadays,the substation inspection robot has been more widely used.As an auto-navigating mobile robot,the first problem needed to be solved for substation inspection robot is self-localization and mapping.As a 3D environment perception sensor with high frequency,high precision and strong robustness,3D lidar becomes the research hotspot in localization and mapping of mobile robots.Under the project ‘Intelligent Substation inspection Robot ' of Guangdong Grid,a localization and mapping system based on 3D lidar has been designed in this thesis,which can realize precise positioning and building the point cloud map of environment under the situation without GPS.The main works of this thesis are as followes:First,the attitude representation and motion estimating principle based on point cloud matching are researched.Meanwhile,the accuracy and time consuming of several point cloud matching algorithms are compared by experiments.The superiority of the matching algorithm based on PTL&P is proved.Then,the mathematical models of two methods based on filtering and optimizationa are researched.A new method of graph-based slam based on 3D lidar is proposed,by global graph optimizing solution with loop detection and modifying the accumulative error of point cloud matching,the optimal map and robot pose estimation can be obtained,which provides accurate transcendent environmental data for localization based on map.Next,a method of multi-sensor integrated positioning based on point cloud map is proposed.It can solve the problem of 3D special localization for robot without GPS by complementary filter algorithm which combines the prediction results of odometer and inertial navigation system,as well as the observation results of 3D lidar.Finally,based on the experimental platform of the mobile robot with 3D lidar,odometer,inertial navigation system and other multi-sensor that constructed by Guangdong Grid,the algorithms proposed in the thesis is tested under multiple environments.It shows that the proposed method of localization and mapping has high accuracy and strong robustness,which is suitable for the environment of substation.