Study Of Ground Mobiles Localization And Path Planning Based On Vision And Ultrasonic Sensors

Being an important sign of the intelligence of mobile robots, self-localization and path planning of service robots and military robots are studied in order to provide guaranties of theories and technologies for factual application of mobile robots.A single ultrasonic receiver is designed to measure multi-distance. A half of the peak of receiving signal is used as the threshold in calibration and then a small threshold is used in measure. Localization is completed in dynamic environment by dividing indoor space and eliminating bad values according to the characteristics of spatial regions and also by serial and parallel deduction.Some visual landmarks with directional channels and positional channels are designed for mobile robots to localize in an indoor environment. An appropriate dynamic threshold is selected for dividing up an image of a landmark according to the relation of energy and then the information on the landmark is picked up by scan.An appropriate threshold acting as"the lowest mark of matriculates"is used to show stairs edges obviously in a part image after one order differential of the part and then the pose information of the robot on stairs is obtained by the principle of imaging geometry and the method of scanning and clustering. A simple method of control is used to adjust the pose of the robot on the basis of the characteristic of movement.The method of local path planning proposed in the thesis is used to solve delay during communication between human operator and the remote-controlled mobile robot. The best subgoal is selected from eight virtual subgoals in a certain range in front of a robot according to the angle between the direction of the mobile robot navigation and the direction from the robot to the goal, and to the distribution of obstacles in a certain region of the measure range of eight ultrasonic sensors. During the motion of the robot, the best subgoal is refreshed according to a rolling mode.It is proposed that real outlines of obstacles are replaced by quadrangles, A path consisted of beelines is planned after coarse path planning based on quadrangles and then these beelines are connected with curve lines along borders of obstacles between them. Short side of an obstacle border is selected for robots to escape from surrounded place under the condition of the start or the goal in a quadrangle. The method is characteristic of the convenience of image pretreatment and the optimum path and shorter time spent on path planning.Electromagnetic wave is used as the signal source of a goal. The distance between a robot and the goal is measured according to the intensity of electromagnetic wave in order to search the goal dynamically. The method is affected little by environmental weather.