The multitarget tracking of multirobot systems has a wide range of applications, including urban security, search, and rescue. However, these tasks often take place in obstacle-rich environments, posing significant challenges, such as an unknown global map, unclear target locations, and inefficient resource allocation. In this article, we propose an air–ground cooperative hierarchical method for multitarget tracking. The uncrewed aerial vehicle (UAV) is equipped with a fisheye camera to provide a wide field of view (FOV) for multitarget detection and an initial global map generated from segmented aerial images. Multiple targets are assigned to uncrewed ground vehicles (UGVs) using the task allocation method, which is based on the PIO and auction mechanism. UGV track targets through motion planning to avoid obstacles and keep their assigned targets in the FOV. Experimental validation confirmed the effectiveness of our method, demonstrating that UGVs can autonomously and reliably track targets in obstacle-rich environments with UAV assistance.

Flapping Wing Rotorcraft (FWR) combines flapping and rotating wing motion in one element. Such a hybrid design integrates the high-efficiency characteristics of the rotating wing and the high-lift feature of the flapping wing under low Reynolds number, providing a broader range of simultaneous lift and power efficiency optimization. Nevertheless, the flight performance of the current FWRs is limited by their complex transmission mechanisms. Such mechanical constraints not only induce coupled wing kinematics but also render tedious assembly work and fabrication imperfections. In order to fundamentally address the constraints, we propose a motor-driven FWR with mechanically decoupled wings. The wing of the proposed DFWR is directly actuated by two bi-directional rotating motors instead of using the crank rocker (or alike) transmission. The proposed DFWR flaps within 25Hz to 35Hz, with about 12.4 grams of system weight and 185mm wingspan. With the direct-drive principle, the wing kinematics can be modulated properly by real-time motor control. In particular, we tuned the flapping frequency, stroke amplitude, and mid-stroke angle of the proposed direct-drive FWR to attain its best lift performance. As a result, it can generate about 16 grams of maximum total lift. In order to validate the proposed design, free flight tests have been conducted. The proposed FWR demonstrates stable liftoff.