Coverage path planning (CPP) of multiple Dubins robots has been extensively applied in aerial monitoring, marine exploration, and search and rescue. Existing multi-robot coverage path planning (MCPP) research use exact or heuristic algorithms to address coverage applications. However, several exact algorithms always provide precise area division rather than coverage paths, and heuristic methods face the challenge of balancing accuracy and complexity. This paper focuses on the Dubins MCPP problem of known environments. Firstly, we present an exact Dubins multi-robot coverage path planning (EDM) algorithm based on mixed linear integer programming (MILP). The EDM algorithm searches the entire solution space to obtain the shortest Dubins coverage path. Secondly, a heuristic approximate credit-based Dubins multi-robot coverage path planning (CDM) algorithm is presented, which utilizes the credit model to balance tasks among robots and a tree partition strategy to reduce complexity. Comparison experiments with other exact and approximate algorithms demonstrate that EDM provides the least coverage time in small scenes, and CDM produces a shorter coverage time and less computation time in large scenes. Feasibility experiments demonstrate the applicability of EDM and CDM to a high-fidelity fixed-wing unmanned aerial vehicle (UAV) model.

Robotic technologies and applications have recently witnessed remarkable advancements. A major challenge is the shortest-path planning problem of a curvature-bounded vehicle from the known starting configuration to visit a target point and finally return to the starting configuration in an obstacle environment. Spurred by this significant issue in robotic surveillance and patrolling applications, this paper proposed the Two-trip Obstacle-environment Relaxed Dubins Problem (TORDP). In TORDP, the vehicle’s target-visiting heading is a critical variable. Analytical approaches have existed for simpler scenarios than TORDP. However, these approaches are unavailable when solving the complex TORDP simultaneously with bounded curvature, variable target heading and unified ability to tackle with- or without- obstacle cases. Hence, we develop the mixed-integer piecewise-linear program (MIPWLP) approach, making the otherwise intractable complex scenario unifiedly solved with guaranteed good quality. Extensive experiments demonstrate that the proposed approach demonstrates effective performance. Furthermore, the objective approximation error in some cases was analyzed to achieve a length near the optimal length within $h^{2}/(2\sqrt {2})$ tolerance where h is the approximation piece length. The proposed MIPWLP approach could also offer a generalizable optimization framework for broader robotic path-planning applications in constrained environments.

Nowadays, Unmanned Aerial Vehicles (UAVs) are playing increasingly important roles in agriculture, rescuing and surveillance due to their small size, low cost and strong adaptability. Coverage Path Planning (CPP) is a fundamental problem for UAV applications, which means to find a path covering all the targets or regions of interest. Researches on CPP in a single region have been studied for decades, but rare to be devoted to covering multiple scattered regions of multiple UAVs. This paper proposes an attempt to solve this problem in a short time and take the task balance of multiple UAVs into account meanwhile. This work constructs a model for multiple UAVs to cover scattered regions firstly. In view of the high computational complexity of the precise solution, we keep innovating a heuristic measure based on the model to make the solving process feasible. To settle the problem of imbalanced time consumption caused by super regions, we improve the previously built model furthermore. A series of experiments validated that the presented approaches exhibit the effectiveness and balance of time consumption in diverse scenarios.

Rotating machinery is essential to modern industrial systems, where rolling bearings play a critical role in ensuring mechanical stability and operational efficiency. Failures in bearings can result in serious safety risks and significant financial losses, which highlights the need for accurate and robust methods for diagnosing bearing faults. Traditional diagnostic methods relying on single-source data often fail to fully leverage the rich information provided by multiple sensors and are more prone to performance degradation under noisy conditions. Therefore, this paper proposes a novel bearing fault diagnosis method based on a multi-level fusion framework. First, the Symmetrized Dot Pattern (SDP) method is applied to fuse multi-source signals into unified SDP images, enabling effective fusion at the data level. Then, a combination of RepLKNet and Bidirectional Gated Recurrent Unit (BiGRU) networks extracts multi-modal features, which are then fused through a cross-attention mechanism to enhance feature representation. Finally, information entropy is utilized to assess the reliability of each feature channel, enabling dynamic weighting to further strengthen model robustness. The experiments conducted on public datasets and noise-augmented datasets demonstrate that the proposed method significantly surpasses other single-source and multi-source data fusion models in terms of diagnostic accuracy and robustness to noise.

Generative adversarial networks as a powerful technique is also used in domain adaptation (DA) problem. Existing adversarial DA methods mainly conduct domain-wise alignment to alleviate marginal distribution shift between the two domains, while it may damage latent discriminative structure hidden in data feature space and cause negative transfer accordingly. To handle this problem, we propose a joint adversarial domain adaptation method with structural graph alignment to minimize joint distribution bias by further realizing class-wise matching (conditional distribution shift) based on a simple sampling strategy except for the domain-wise alignment, and validate that simultaneously considering these two types of shift can approximately reduce the joint distribution bias. To explore transferable structural information and realize more sufficient transfer for DA problem, we propose to align structural graphs between the two domains which is also based on a simple sampling strategy. Notably, the structural graph describes the relationship between each two samples and it is computed on two domains. As such, we can learn new feature representation of the two domains which are more discriminative and transferable to benefit a cross-domain classification task desirably. Finally, we design a number of experiments to evaluate our approach on four public cross-domain benchmark datasets including standard and large-scale ones, and empirical results show that the proposed model can outperform compared state-of-the-art methods.