Research on a semiautonomous mobile robot for loosely structured environments focused on transporting mail trolleys

In this thesis is presented a novel approach to model, control, and planning the motion of a nonholonomic wheeled mobile robot that applies stable pushes and pulls to a nonholonomic cart (York mail trolley) in a loosely structured environment. The method is based on grasping and ungrasping the nonholonomic cart, as a result, the robot changes its kinematics properties. In consequence, two robot configurations are produced by the task of grasping and ungrasping the load, they are: the single-robot configuration and the robot-trolley configuration. Furthermore, in order to comply with the general planar motion law of rigid bodies and the kinematic constraints imposed by the robot wheels for each configuration, the robot has been provided with two motorized steerable wheels in order to have a flexible platform able to adapt to these restrictions. [Continues.

The use of aerial images and GPS for Mobile Robot Waypoint Navigation

The application of aerial and satellite imagery for mobile robot path planning and navigation has shown potential in recent years. These uses vary from identifying terrain properties for creating traversability maps to extracting landmarks for autonomous navigation. With the freely available differential positioning system WAAS/EGNOS, the use of the Global Positioning System with aerial images providing valuable contextual data, demonstrates potential in waypoint-based navigation of mobile robots. However, important issues relating to the spatial accuracies of image, waypoint and GPS derived data, vital for obtaining accurate navigation results, are often overseen. This paper defines the causes of spatial inaccuracies in order to develop optimal waypoint navigation parameters and provides researchers with sufficient knowledge to reproduce similar results. An improvement of up to 48% in the number of waypoints reached, depending on the radius, was determined for the positional correction of the GPS. The reader is presented with a method for easily creating waypoints from aerial images, yielding results to a similar level of accuracy to conventional and often tedious manual methods. The results are shown with a simulated synchronous drive robot in Matlab’s Simulink®environment