Monocular Snapshot-based Sensing and Control of Hover, Takeoff, and Landing for a Low-cost Quadrotor

Abstract

Autonomous control of a low-cost micro air vehicle (MAV) is considered, using a single camera and inertial measurement unit. Integration of loom is used to determine the approximate height during takeoff and landing, and to provide an initial height for hover. Contrary to most optic-flow-based approaches that lack positional feedback, a “snapshot” paradigm is utilized in this paper that takes and stores an image of the ground under the MAV as a reference image, and the position of the vehicle can then be estimated from the transformation of the following images with respect to the reference image so that long-term drift can be contained. In this new work, the implementation of the snapshot algorithm is considered with a focus on real-time performance on a slow processor and the difficulties posed by illumination change and external disturbance. We also extend earlier work with extensive flight experiments conducted in various situations to evaluate the closed-loop performance of the proposed algorithm.