Application of Differential Global Positioning System and Path Planning to Robot Outdoor Patrol

摘要

In this paper, we present a robot outdoor patrol that applies a differential global positioning system (DGPS), an encoder, a web camera, and a laser sensor with an improved A* algorithm to achieve fixed route patrol. Obstacle avoidance by smooth pathfinding in complicated unknown environments is also considered. While in fixed route patrolling, the DGPS provides locations of the wheeled mobile robot (WMR) and the corners of buildings. By image processing and the wheel's encoder, the orientation of the WMR can be calibrated if the web camera has deviation angles to the target building. Along the patrol path, people or other obstacles may block the WMR while patrolling, so the laser sensor is used to provide the distances and edge values of such obstacles. This information is then used to improve the A* algorithm to achieve the shortest and smoothest path. A fuzzy controller is used to assist the WMR with obstacle avoidance in unknown environments. After finishing a patrol, the WMR system will send a message to a security guard to report whether the patrol region is in normal condition. If the camera detects an unidentified person, the robot will send the location of the person to the control center and ask for help.