Tunnels are a challenging environment for radio communications. In this paper we consider the use of autonomous
mobile radio nodes (AMRs) to provide wireless tethering between a base station and a leader in a tunnel exploration
scenario. Using a realistic, experimentally-derived underground radio signal propagation model and a tethering
algorithm for AMR motion control based on a consensus variable protocol, we present experimental results involving a
tele-operated leader with one or two followers. Using radio signal strength measurements, the followers autonomously
space themselves so as to achieve equal radio distance between each entity in the chain from the base to the leader.
Results show the feasibility of our ideas.
Much of the success of small unmanned air vehicles (UAVs) has arguably been due to the widespread availability of
low-cost, portable autopilots. While the development of unmanned ground vehicles (UGVs) has led to significant
achievements, as typified by recent grand challenge events, to date the UGV equivalent of the UAV autopilot
is not available. In this paper we describe our recent research aimed at the development of a generic UGV
autopilot. Assuming we are given a drive-by-wire vehicle that accepts as inputs steering, brake, and throttle
commands, we present a system that adds sonar ranging sensors, GPS/IMU/odometry, stereo camera, and
scanning laser sensors, together with a variety of interfacing and communication hardware. The system also
includes a finite state machine-based software architecture as well as a graphical user interface for the operator
control unit (OCU). Algorithms are presented that enable an end-to-end scenario whereby an operator can view
stereo images as seen by the vehicle and can input GPS waypoints either from a map or in the vehicle's scene-view
image, at which point the system uses the environmental sensors as inputs to a Kalman filter for pose estimation
and then computes control actions to move through the waypoint list, while avoiding obstacles. The long-term
goal of the research is a system that is generically applicable to any drive-by-wire unmanned ground vehicle.
Conference Committee Involvement (1)
Tenth International Symposium on Medical Information Processing and Analysis