Robust Visual-Aided Autonomous Takeoff, Tracking, and Landing of a Small UAV on a Moving Landing Platform for Life-Long Operation

Abstract

Robot cooperation is key in Search and Rescue (SaR) tasks. Frequently, these tasks take place in complex scenarios affected by different types of disasters, so an aerial viewpoint is useful for autonomous navigation or human tele-operation. In such cases, an Unmanned Aerial Vehicle (UAV) in cooperation with an Unmanned Ground Vehicle (UGV) can provide valuable insight into the area. To carry out its work successfully, such as multi-robot system requires the autonomous takeoff, tracking, and landing of the UAV on the moving UGV. Furthermore, it needs to be robust and capable of life-long operation. In this paper, we present an autonomous system that enables a UAV to take off autonomously from a moving landing platform, locate it using visual cues, follow it, and robustly land on it. The system relies on a finite state machine, which together with a novel re-localization module allows the system to operate robustly for extended periods of time and to recover from potential failed landing maneuvers. Two approaches for tracking and landing are developed, implemented, and tested. The first variant is based on a novel height-adaptive PID controller that uses the current position of the landing platform as the target. The second one combines this height-adaptive PID controller with a Kalman filter in order to predict the future positions of the platform and provide them as input to the PID controller. This facilitates tracking and, mainly, landing. Both the system as a whole and the re-localization module in particular have been tested extensively in a simulated environment (Gazebo). We also present a qualitative evaluation of the system on the real robotic platforms, demonstrating that our system can also be deployed on real robotic platforms. For the benefit of the community, we make our software open source.

A Decade of UAV Docking Stations: A Brief Overview of Mobile and Fixed Landing Platforms

“…Some of them are Unmanned Ground Vehicles which have landing systems mounted on, like in [65][66][67][68][69][70][71]. The UGV can be used to swap the battery of a UAV, like in [72] or to wirelessly charge the battery- [35,73,74]. The UGV solutions for mobile docking stations are the most often used solutions since UAVs are mostly used above land.…”

Autonomous Quadcopter Precision Landing Onto a Heaving Platform: New Method and Experiment

“…Noting that α x and α y are the horizontal and vertical fields of view of the camera. Substituting (19) into (18) yields:…”

“…In another research presented in [15], the authors used the global positioning system (GPS) navigation to enable a quadcopter to find a moving platform and a vision-based control to approach and land onto it. Many other vision-based approaches coming with different controllers were presented including the studies in [16] with a model predictive controller, [17] with adaptive proportionalintegral-derivative (PID) altitude controllers, [18] with a neural network controller, [19] with a multi-level fuzzy logic controller, and [20] with a backstepping controller. Meanwhile, some other approaches focus more on improving the landing target state estimation [21]- [24].…”

Nano and Micro Unmanned Aerial Vehicles (UAVs): A New Grand Challenge for Precision Agriculture?

“…Interestingly, flight capacities for MAVs and NAVs can be improved based on characteristics of the flight of insects, known as the best natural fliers regarding hovering capabilities (Throneberry et al., 2017). Furthermore, although their reduced size can constrain their coverage area, swarming protocols that include several NAVs flying in a coordinated manner can overcome this issue (Kumar, 2016), or robot mobile landing platforms can widen their coverage (Palafox et al., 2019) while the batteries recharge to be ready for the next flight. Still, very few examples of these technologies can be seen currently applied to precision agriculture; however, the opportunities offered by MAVs and NAVs (reducing safety requirements and hazards due their low weight) are highly relevant to generalizing their use in precision agriculture for the purposes of resource efficiency, pest control, and productivity.…”

“…By flying closer to the plant, MAVs and NAVs increase the possibilities for measuring previously unseen variables that are important for precision agriculture and phenotyping and, in doing so, further minimize calibration requirements. These very small UAVs are at the center of an emergent and intense field of research, ranging from optimization of their flight capacities, new aircraft designs, energy supply, and swarming modes to network development to establish collaborative missions with another sensors and robots (Faryadi, Davoodi, & Mohammadpour Velni, 2019; Kumar, 2016; Palafox, Garzón, Valente, Roldán, & Barrientos, 2019; Throneberry, Hassanalian, & Abdelkefi, 2017).…”