Robot-Assisted Drone Recovery on a Wavy Surface Using Error-State Kalman Filter and Receding Horizon Model Predictive Control

Recovering a drone on a disturbed water surface remains a significant challenge in maritime robotics. In this paper, we propose a unified framework for Robot-Assisted Drone Recovery on a Wavy Surface that addresses two major tasks: Firstly, accurate prediction of a moving drone's position under wave-induced disturbances using an Error-State Kalman Filter (ESKF), and secondly, effective motion planning for a manipulator via Receding Horizon Control (RHC). Specifically, the ESKF predicts the drone's future position 0.5s ahead, while the manipulator plans a capture trajectory in real time, thus overcoming not only wave-induced base motions but also limited torque constraints. We provide a system design that comprises a manipulator subsystem and a UAV subsystem. On the UAV side, we detail how position control and suspended payload strategies are implemented. On the manipulator side, we show how an RHC scheme outperforms traditional low-level control algorithms. Simulation and real-world experiments - using wave-disturbed motion data - demonstrate that our approach achieves a high success rate - above 95% and outperforms conventional baseline methods by up to 10% in efficiency and 20% in precision. The results underscore the feasibility and robustness of our system, which achieves state-of-the-art (SOTA) performance and offers a practical solution for maritime drone operations.

Unsupervised Cross-spectral Stereo Matching by Learning to Synthesize

Unsupervised cross-spectral stereo matching aims at recovering disparity given cross-spectral image pairs without any supervision in the form of ground truth disparity or depth. The estimated depth provides additional information complementary to individual semantic features, which can be helpful for other vision tasks such as tracking, recognition and detection. However, there are large appearance variations between images from different spectral bands, which is a challenge for cross-spectral stereo matching. Existing deep unsupervised stereo matching methods are sensitive to the appearance variations and do not perform well on cross-spectral data. We propose a novel unsupervised cross-spectral stereo matching framework based on image-to-image translation. First, a style adaptation network transforms images across different spectral bands by cycle consistency and adversarial learning, during which appearance variations are minimized. Then, a stereo matching network is trained with image pairs from the same spectra using view reconstruction loss. At last, the estimated disparity is utilized to supervise the spectral-translation network in an end-to-end way. Moreover, a novel style adaptation network F-cycleGAN is proposed to improve the robustness of spectral translation. Our method can tackle appearance variations and enhance the robustness of unsupervised cross-spectral stereo matching. Experimental results show that our method achieves good performance without using depth supervision or explicit semantic information.