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

Abstract

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 (333 Hz) 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.

Signal-Based Self-Organization of a Chain of UAVs for Subterranean Exploration

“…In addition, the miniature Lidars onboard help the UAVs to fly at a nearly constant height, which means that measured optic flow is therefore proportional to the ground speed. Optic flow sensors can also work in low-light conditions (Mafrica et al, 2016). Recent commercial optic flow sensors are derived from optical mouse sensors (e.g., Pixart PMW3901MB) and weight only a few milligrams.…”

Signal-based self-organization of a chain of UAVs for subterranean exploration

“…Our main insights are that (1) we know that the signal quality is likely to decrease when two UAVs move away from each other, and (2) the relative speed of two UAVs can be measured at no computational cost with miniature optic flow sensors [21] (commercial optical flow sensors derived from optical mouse sensors, like the Pixart PMW3901MB, weight a few mg and can work in low-light conditions [22]).…”

Minimalistic optic flow sensors applied to indoor and outdoor visual guidance and odometry on a car-like robot

“…An extended Kalman filter (EKF) was used to estimate the robot's velocity and steering angle using only the OF measurements delivered by two downwardfacing sensors, as presented in [52] in the case of a single indoor environment. In the present paper, the tests were extended to various indoor (see online supplementary video 1) and outdoor (see online supplementary video 2) testing conditions, including various light levels, ground textures, trajectories and vibrations, and the robot's absolute position and orientation were estimated in real time using the EKF estimates and the Ackerman steering model.…”