Construction Of Mobile Service Robot And Safety Verification Of Autonomous Navigation System

In recent years,robot technology experiences a rapid development.Gradually,robot industry extended from conventional manufacturing area to common service area.Robot started to appear in the family,working place as well as public environment,leading to a key question:how to make a safe navigation for the robot in unknown environment.In this thesis,a robot intelligent service platform was constructed.Later,a robot simulation model was established according to the specific robot category.Besides,we also checked path planning algorithm application results.Finally,service robot security property was demonstrated by formal verification,which ensures the high reliability of the robot platform.Firstly,this thesis introduces the experimental platform of the study,a ROS system framework based intelligent service robot.This platform uses a depth camera as visual sensor.The software system was designed to achieve three functions,including autonomous obstacle avoidance,target tracking&photographing and intelligence alternation.Besides,the system has good portability and scalability.Next,we studied functional requirements of service robot target tracking under a complex environment.We also developed a local path planning strategy for dynamic window obstacle avoidance,based on point cloud data and robot size constraint requirement.In order to improve robot obstacle avoidance and target tracking ability,apart from Dynamic Window Approach,we used another two strategies.One is checking motion region connectivity in the visual field,the other is taking path width and robot self-size into consideration.Finally,modeling and verification was operated by formal verification method,according to the hybrid system characteristics.The state space of nonlinear systems was abstracted and divided based on abstraction method and differential dynamic logic analysis.Then the robot system safety boundary definition problem was transformed into a model constraint problem.We demonstrated that all possible states of the system meet the passive safety definition,as long as security constraints are met.All these work demonstrate that the safety verification of the navigation system meets the requirement.