Biologically Inspired Collision Avoidance Without Distance Information
This addresses collision avoidance for small, low-cost robots and UAVs that cannot carry distance sensors, though it is incremental as it builds on known biological principles.
The paper tackles collision avoidance for robots without distance sensors by proposing a biologically inspired control framework that uses only line-of-sight angle, its rate, and time-to-collision from a monocular camera, achieving guaranteed minimum separation from obstacles.
Biological evidence shows that animals are capable of evading eminent collision without using depth information, relying solely on looming stimuli. In robotics, collision avoidance among uncooperative vehicles requires measurement of relative distance to the obstacle. Small, low-cost mobile robots and UAVs might be unable to carry distance measuring sensors, like LIDARS and depth cameras. We propose a control framework suitable for a unicycle-like vehicle moving in a 2D plane that achieves collision avoidance. The control strategy is inspired by the reaction of invertebrates to approaching obstacles, relying exclusively on line-of-sight (LOS) angle, LOS angle rate, and time-to-collision as feedback. Those quantities can readily be estimated from a monocular camera vision system onboard a mobile robot. The proposed avoidance law commands the heading angle to circumvent a moving obstacle with unknown position, while the velocity controller is left as a degree of freedom to accomplish other mission objectives. Theoretical guarantees are provided to show that minimum separation between the vehicle and the obstacle is attained regardless of the exogenous tracking controller.