Low Cost Autonomous Vehicles Using Just Gps

摘要

Abstract NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract Low-Cost Autonomous Vehicles Using Just GPS Michael E. Holden San Francisco State University Introduction The Navigator is an autonomous ground vehicle. Using a commercial handheld GPS as its only sensor, it is able to follow a preprogrammed path and speed with remarkable accuracy. Assembled from a model car chassis, inexpensive 8-bit microcontroller and GPS, it is about as simple as autonomous ground vehicles can be. This simplicity makes it easy for students unfamiliar with autonomous vehicles to understand the system, keeps the system cost low, and allows for a truly miniature guidance and navigation electronics package. The simplicity also provides engineering challenges, such as navigating using only the infrequent sensor data from the GPS, and working within the limits of GPS accuracy and discretization. Originally designed for a middle-school after-school program for disadvantaged students1 (as a consulting project for the MLB Company2), the Navigator has been used for undergraduate and graduate education as well. It has an LCD display and 4 button interface that make its operation easy even for the non-engineer, while engineering students can use the interface to adjust feedback gains without reprogramming the controller. For graduate students starting autonomous vehicle research projects, the Navigator is a good starting point from which to build more complex vehicles. The Navigator is primarily an educational tool—although it is a capable platform, its lack of external sensors makes it useful only in areas free of obstacles. The electronics are extendable to other platforms, such as boats (which are less likely to be obstructed) and robotic bases with external sensors for collision avoidance. There are many remote sensing applications that can make use of an inexpensive autonomous ground or water vehicle, and the author is pursuing collaborations that will use the Navigator as a research tool instead of merely as a research subject. This paper will describe the Navigator, its control algorithms and electronic assembly, as well as the educational uses it has been a part of to date. Data from using the Navigator electronics as a boat controller will also be shown. Figure 1 shows an example of an operational Navigator. Vehicle Description The Navigator’s purpose is to drive itself along a pre-programmed path at a given speed. The path is made up of straight-line legs between waypoints, and the car follows the path at a speed specified for each leg. Figure 2 shows a sample path. The waypoints define the path, and the speed associated with each waypoint defines the speed the Navigator will hold while heading for that waypoint. Proceedings of the 2004 American Society for Engineering Education Annual Conference & Exposition Copyright © 2004, American Society for Engineering Education