Onboard Hover Control of a Quadrotor using Template Matching and Optic Flow

Autonomous hover control of a low-cost Micro Air Vehicle (MAV) is considered in this paper. To avoid the long-term drift during hover, the ‘snapshot’ idea is practiced, where an image of the ground under the MAV is stored as the reference image, and the following images are directly compared with this reference image for estimating horizontal position. For hover control, the measured position is used in conjunction with the speed estimated from frame-to-frame image motion. All computations are performed onboard the vehicle and controller parameters are roughly tuned in the experiments. Flight tests carried out both indoors and outdoors prove the effectiveness of the proposed method for the hover control of a MAV.