| The aging of our society is becoming more and more obvious,and the challenge of caring for the elderly has become a social issue in China.In order to better care for the elderly,disabled and other people with mobility problems,home care robots and their related technologies have emerged.In the study of home care robots,autonomous navigation technology is an indispensable function of home care robots.Therefore,this thesis conducts research on technologies related to autonomous navigation of home care robots based on Robot Operating System,and the main work is as follows.Firstly,the system structure and physical quantity parameters of the home care robot are introduced,and the kinematic model of the home care robot is established.To address the accuracy of sensor information,the data collected by odometer and Li DAR are pre-processed to improve the accuracy of robot positioning.And the overall scheme design of the indoor autonomous navigation system of the home care robot is completed based on the ROS robot operating system.Secondly,two laser mapping algorithms,Gmapping and Cartographer,are analyzed and compared,and the Cartographer algorithm is finally chosen as the mapping method by considering the mapping scenario and mapping accuracy,and the mapping effect of the algorithm is verified through experiments.The Adaptive Monte Carlo Localization algorithm was studied and selected for global localization of the robot,and the accuracy of the algorithm in estimating the pose of the robot was verified through experiments.Thirdly,a raster-topology hybrid map-based SHS path planning method is proposed to address the problem of positioning failure due to the planned path being close to an obstacle when the robot plans a route through a door using the traditional global path planning algorithm.The method first constructs a raster-topology hybrid map by selecting topological points on the established raster map,and then combines Dijkstra’s algorithm with A* algorithm to perform global path planning on the raster-topology hybrid map.It is verified through experiments that the improved global path’s improves safety and can quickly plan a safe collision-free path through the door in a more complex home environment.Finally,a new evaluation function is proposed to address the problems that exist when the robot uses the traditional Dynamic Window Approach for local path planning.In order to improve the disadvantage that the dynamic window method will make the robot deviate from the target point when it is closer to the target point,the distance parameter between the end of the predicted trajectory and the target point is introduced into its evaluation function to improve the robot’s speed control when it is close to the target point;in order to make the robot traverse the dense area of obstacles,the adaptive weight factor of the evaluation function is introduced to improve the robot’s environmental adaptability.The feasibility and effectiveness of the proposed improved dynamic window method for local path planning are verified by experiments. |
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