Safe Navigation in Dynamic Environments

This paper addresses the issue of motion safety for on-line navigation in dynamic environments. Using velocity obstacles to represent the dynamic environment, we propose to truncate the velocity obstacle by the minimum time horizon, computed to ensure that the velocity obstacle is truncated close to the boundary of the set of inevitable collision states. Thus, using the velocity obstacle to select potential avoidance maneuvers would ensure that only safe maneuvers are being selected. The concept of velocity obstacles was known for some time, but the issue of how to truncate it without compromising safety was not addressed until recently. The computation of the minimum time horizon is formulated as a minimum time problem, which is solved numerically for each static or moving obstacle. The “safe” velocity obstacles are used in an on-line planner that generates near-time optimal trajectories to the goal. The planner is demonstrated for on-line motion planning in very crowded static and dynamic environments.