Optic-flow based car-like robot operating in a 5-decade light level range

In this paper, we present (i) a novel bio-inspired 1-D OF sensor which is robust to high-dynamic-range lighting conditions and independent of the visual patterns encountered, and (ii) a low-cost car-like robot called BioCarBot, which estimates its velocity and steering angle by means of an Extended Kalman Filer (EKF) using only the OF measurements delivered by two downward-facing sensors of this kind. Indoor experiments were carried out, in which the robot was driven in the closed-loop mode, using a proportional integral (PI) controller based on the velocity and steering angle estimates. The results presented here show that our novel OF sensor can deliver a wide range of high-frequency (333Hz) OF measurements (from 1 to 10 rad/s ) with a relatively high resolution (up to 0.05 rad/s) in a 5-decade high-dynamic range of light levels. Neither the refresh rate nor the resolution of the OF sensors presented here depended on either the visual patterns or the lighting conditions, and could be theoretically set at whatever value required.