Abstract: By integrating multiple modes of locomotion, such as aerial, ground, and surface or underwater operations, multi-modal unmanned aerial vehicles (UAVs) overcome the inherent limitations of single-mode robots in terms of endurance, terrain adaptability, and operational range. They have thus become a significant research direction in the field of robotics. This paper systematically reviews the recent research progress in multi-modal UAV technology, presenting a comprehensive overview from four dimensions: system configuration, key technologies, challenges, and future trends. In terms of configuration, amphibious aerial-ground, aerial-aquatic, and tri-modal UAVs are classified according to their structural design characteristics, and the advantages, disadvantages, and applicable scenarios of solutions such as wheeled, legged, and morphing structures are analyzed. Regarding key technologies, this review summarizes existing research achievements and their limitations, focusing on core issues including motion planning and trajectory optimization, control system design, and cross-medium communication and perception. Building on this analysis, the paper explores the main challenges currently facing multi-modal UAVs, such as structural lightweighting, robustness during mode switching, energy management, and autonomous decision-making. Finally, it identifies the deep integration of structure and function, intelligent control and autonomous decision-making, collaborative swarm operations, and the application of novel energy sources and advanced materials as critical directions for future development. Read More

Abstract: This paper addresses the issue of lateral vibration of high - speed train car bodies caused by random track irregularity excitation and random wind excitation. It proposes an active control method based on the SABO - LQR algorithm and the secondary suspension system to enhance the running stability and safety of high - speed trains by suppressing the lateral vibration of the car body. First, a dynamic model of the cross - wind - vehicle - track system is established, taking into account both random track irregularity excitation and random wind excitation. Second, considering the difficulty in selecting the weight matrices Q and R during the design of the LQR controller, the SABO algorithm is used for iterative optimization to obtain the optimal weight matrices and the controller. Finally, the effectiveness of the proposed method is further verified through simulation. The results show that the proposed active control method based on the SABO - LQR algorithm and the secondary suspension system has the potential to effectively suppress the lateral vibration of the train car body. Compared with the passive suspension method and the LQR control method, this method can reduce the amplitude of the car body's lateral vibration by 67.13% and 50.30% respectively, thus improving the riding comfort and the running stability of high - speed trains. Read More

Abstract: Hexapod robots, their exceptional static stability, redundant limb structures, and strong terrain adaptability, demonstrate broad application prospects in fields such as interstellar exploration, disaster rescue, military reconnaissance, and complex environment operations. Based on a systematic review of multiple high-quality academic papers published in recent years, this paper provides an in-depth review of the current state of hexapod robot technology from key dimensions, including mechanical structure design and optimization, kinematics and dynamics modeling, gait planning and motion control, environmental perception and autonomous decision-making, and adaptability under special operating conditions. The analysis indicates that current research is shifting from traditional single-structure, regular gait, and model-dependent control toward lightweight/reconfigurable structures, adaptive gaits for complex terrains, and intelligent control based on deep reinforcement learning. In the future, integrating advanced sensing technologies and achieving higher autonomy and environmental robustness will be key breakthroughs in hexapod robot research. Read More

Abstract: Excavators are important equipment in many construction projects. In the process of intelligentisation, the technological advancements they have undergone are no longer covered solely by hydraulic technology, but are being explored from multiple perspectives towards the integration of mechanical, electrical, and hydraulic systems. In recent years, the industry has made certain progress in three-dimensional environmental perception and remote operation, and some key technologies have initially established a foundation for engineering applications. However, due to the poor robustness of perception systems and the difficulty of establishing accurate models under complex working conditions, a high level of autonomous operation capability cannot yet be achieved. These issues need to be addressed in the future for excavators to enter the era of intelligentisation Read More

Abstract: Thermal management of lithium-ion batteries is critical to ensuring their safe and efficient operation. Phase change materials (PCM) and heat transfer enhancement with fins are mainstream technical solutions at present. In this paper, a topology-optimized fin-PCM composite thermal management model is constructed for 2×3 array 18650 lithium-ion batteries. The thermal performance of three PCMs is compared via numerical simulation, and the influences of phase change temperature, latent heat and thermal conductivity on the maximum battery temperature, maximum temperature difference and liquid fraction are analyzed. The results show that PCM 2 achieves the optimal balance among latent heat capacity, phase change temperature and thermal conductivity under 3C and 4C discharge conditions. At the end of discharge, the maximum temperature of PCM 2 is reduced by 2.49% and 6.17% (3C), 8.54% and 6.12% (4C) compared with PCM 1 and PCM 3, respectively. Meanwhile, PCM 2 presents a stable liquid fraction variation and the best thermal buffering effect. This study can provide a reference for material selection and structural design of passive thermal management systems for high-rate lithium-ion batteries. Read More