AUVs: In space, air, water, and on the ground

Autonomous unmanned vehicles (AUVs) have generated much interest in recent years due to their great promise for performing repetitive, dangerous, or information- gathering tasks in hazardous or remote environments. The diversity of environments in which these vehicles must operate (space, air, water, ground, and combinations thereof) results in a wide variety of vehicle types. In addition, the requirement for autonomy from direct human interaction places heavy emphasis on reliable control strategies. This special issue presents four articles that focus on control strategies for each of the four types of terrain. Although these articles represent just a tiny sampling of research in the field of AUVs, they should give the reader an understanding of some of the approaches being taken in the design, modeling, and control of these vehicles, as well as the many challenges facing designers. Among these challenges are communications, sensors, materials, locomotion, end-effectors, cooperative control and machine-level control, as well as computational horsepower. Each article addresses several or all of these issues, as well as possible approaches. Other special issues (e.g., 2-4) have also addressed these challenges for specific types of AUVs.