tailieunhanh - Feedback Control for a Path Following Robotic Car Patricia Mellodge

Technology is often a consequence of science and engineering — although technology as a human activity precedes the two fields. For example, science might study the flow of electrons in electrical conductors, by using already-existing tools and knowledge. This new-found knowledge may then be used by engineers to create new tools and machines, such as semiconductors, computers, and other forms of advanced technology. In this sense, scientists and engineers may both be considered technologists; the three fields are often considered as one for the purposes of research and reference.[14]. | Feedback Control for a Path Following Robotic Car Patricia Mellodge Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering Dr. Pushkin Kachroo Chair Dr. A Lynn Abbott Dr. Hugh VanLandingham April 2 2002 Blacksburg Virginia Keywords autonomous vehicle intelligent transportation system lateral control nonholonomic path following curvature estimation Copyright 2002 Patricia Mellodge Feedback Control for a Path Following Robotic Car Patricia Mellodge ABSTRACT This thesis describes the current state of development of the Flexible Low-cost Automated Scaled Highway FLASH laboratory at the Virginia Tech Transportation Institute VTTI . The FLASH lab and the scale model cars contained therein provide a testbed for the small scale development stage of intelligent transportation systems ITS . In addition the FLASH lab serves as a home to the prototype display being developed for an educational museum exhibit. This thesis also gives details of the path following lateral controller implemented on the FLASH car. The controller was developed using the kinematic model for a wheeled robot. The global kinematic model was derived using the nonholonomic contraints of the system. This global model is converted into the path coordinate model so that only local variables are needed. Then the path coordinate model is converted into chained form and a controller is given to perform path following. The path coordinate model introduces a new parameter to the system the curvature of the path. Thus it is necessary to provide the path s curvature value to the controller. Because of the environment in which the car is operating the curvature values are known a priori. Several online methods for determining the curvature are developed. A MATLAB simulation environment was created with which to test the above algorithms. The simulation uses the kinematic model