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This article aims at flying target detection and localization of a fixed-wing unmanned aerial vehicle (UAV) autonomous take-off and landing within Global Navigation Satellite System (GNSS)-denied environments. A Chan-Vese model-based approach is proposed and developed for ground stereo vision detection. Extended Kalman Filter (EKF) is fused into state estimation to reduce the localization inaccuracy caused by measurement errors of object detection and Pan-Tilt unit (PTU) attitudes. Furthermore, the region-of-interest (ROI) setting up is conducted to improve the real-time capability. The present work contributes to real-time, accurate and robust features, compared with our previous works. Both offline and online experimental results validate the effectiveness and better performances of the proposed method against the traditional triangulation-based localization algorithm.

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One of the greatest challenges for fixed-wing unmanned aircraft vehicles (UAVs) is safe landing. Hereafter, an on-ground deployed visual approach is developed in this paper. This approach is definitely suitable for landing within the global navigation satellite system (GNSS)-denied environments. As for applications, the deployed guidance system makes full use of the ground computing resource and feedbacks the aircraft’s real-time localization to its on-board autopilot. Under such circumstances, a separate long baseline stereo architecture is proposed to possess an extendable baseline and wide-angle field of view (FOV) against the traditional fixed baseline schemes. Furthermore, accuracy evaluation of the new type of architecture is conducted by theoretical modeling and computational analysis. Dataset-driven experimental results demonstrate the feasibility and effectiveness of the developed approach.

Bionic undulating fins, inspired by undulations of the median and/or paired fin (MPF) fish, have a bright prospective for underwater missions with higher maneuverability, lower noisy, and higher efficiency. In the present study, a coupled computational fluid dynamics (CFD) model was proposed and implemented to facilitate numerical simulations on hydrodynamic effects of the bionic undulating robots. Hydrodynamic behaviors of underwater robots propelled by two bionic undulating fins were computationally and experimentally studied within the three typical desired movement patterns, i.e., marching, yawing and yawing-while-marching. Moreover, several specific phenomena in the bionic undulation mode were unveiled and discussed by comparison between the CFD and experimental results under the same kinematics parameter sets. The contributed work on the dynamic behavior of the undulating robots is of importance for study on the propulsion mechanism and control algorithms. bionic underwater robot, CFD, dynamic behavior, undulating fins Citation:Zhou H, Hu T J, Xie H B, et al. Computational and experimental study on dynamic behavior of underwater robots propelled by bionic undulating fins.