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This article aims to address the in-orbit assembly needs of truss structures in space missions by designing a robot capable of moving on trusses and manipulating parts. To enhance the stability of the robot during movement and part manipulation, inspiration was drawn from the Dynastes Hercules beetle. Building upon detailed research on the Dynastes Hercules beetle, a biomimetic structure was designed for the robot system. Based on specific task requirements, the overall plan of the robot was developed, and its kinematic and dynamic models were derived. A prototype of the robot was created, which is capable of both movement and assembly functions, including handling spherical and rod-like objects. Through a series of experiments conducted with the robot, the research results demonstrated that the proposed design can effectively achieve the intended functions. [ABSTRACT FROM AUTHOR]

The demand for high-performance underwater thrusters in marine engineering is increasing. The concealed, mobile, and efficient underwater ability of fish provides many directions for research. The black ghost knifefish uses only wavy ventral fins to swim and can hover and roll in the water. Based on the physiological and morphological characteristics of the black ghost knifefish, we explored the structure and movement mode of the ventral fin, so as to establish a two-degree of freedom (2-DOF) structural model and kinematic model. We reveal the motion mechanism of the undulating fin propulsion through the constructed model and computational fluid dynamics. It is found that when the fin surface fluctuates, a pair of vortices with opposite directions will be formed on the concave side of the fin surface. These vortices will produce a central jet on the fin surface, provide a reverse impulse for the ventral fin, and make the fin obtain power. In addition, we found that the propulsive force of the ribbon fin along the body direction is positively correlated with the swing amplitude and frequency of the fin movement, and the propulsive torque of the ribbon fin to realize the maneuvering movement increases first and then decreases with the increase of the torsion angle. The research on the structure and motion mechanism of the ribbon fin of the black ghost knifefish provides a basis for the development of a bionic prototype of multi-DOF motion and the control strategy of high-mobility motion. [ABSTRACT FROM AUTHOR]

In response to the requirements of large-scale space in-orbit assembly and the special environment of low gravity in space, this paper proposes a small robot structure with the integration of assembly, connection, and vibration reduction functionalities. Each robot consists of a body and three composite mechanical arms-legs, which can dock and transfer assembly units with the transport spacecraft unit, and also crawl along the edge truss of the assembly unit to a designated location to complete in-orbit assembly while ensuring precision. A theoretical model of robot motion was established for simulation studies, and in the research process, the vibration of the assembly unit was studied, and preliminary adjustments were made to address the vibration issue. The results show that this structure is feasible for in-orbit assembly schemes and has good adjustment ability for flexible vibration. [ABSTRACT FROM AUTHOR]

Deep space exploration can satisfy humanity's curiosity about the origin of life and the evolution of the universe and enhance our understanding of the internal geological structure and climate change of extraterrestrial bodies. The most direct way to explore extraterrestrial bodies is to sample and analyze the regolith. Drilling is the most effective sampling method, and extraterrestrial regolith drills have helped humans acquire many samples in planetary exploration. Developing high applicable and flexible ERDs for extraterrestrial regolith penetration and sampling has attracted strong attention from scientists and engineers worldwide. This paper presents a detailed review of extraterrestrial drilling technologies. Firstly, the particularities of extraterrestrial drilling are introduced. Then, the ERDs utilized in previous planetary exploration missions and the latest advances are reviewed in detail, including the categories, historical context, and (dis)advantages. Next, the general characteristics of extraterrestrial drilling are summarized, including the mainstream approaches to studying the drilling mechanics and thermophysics. Then, the critical technologies of ERDs, from a conceptual design to a practical prototype, are analyzed in depth. Finally, the prospects for extraterrestrial drilling technology are presented, including water ice drilling, long tunnel boring, deep drilling, and intelligent drilling. [ABSTRACT FROM AUTHOR]

To obtain the resources of the moon, humans have launched a series of exploration activities on the moon, and the landing buffer device is an indispensable device on the lander required to perform lunar surface exploration missions. It can effectively protect the lander during landing scientific payloads such as instruments on the lander. Based on the mechanical properties and deformation mechanism of the aluminum honeycomb as buffer material, this paper compares and analyzes different simulation schemes and finally establishes the bonding model of the honeycomb by using the discrete element method; the parameters of the honeycomb material are matched through compression experiments to verify the discrete element honeycomb simulation and the feasibility of the scheme and its parameters. To meet the buffering requirements of large landers, a spider web honeycomb structure is proposed, its modeling method is studied by using the discrete element secondary development program, and the model is compressed as a whole to verify the energy consumption characteristics of the spider web honeycomb structure. Aiming at the honeycomb buffer device during the landing process, the cobweb honeycomb buffer structure and its corresponding landing coupling model were established using the discrete element method, the landing process was simulated and analyzed, and the landing results were predicted to verify the feasibility of the device, providing a reference for the design of the lander and its buffer device. [ABSTRACT FROM AUTHOR]

The seahorse relies on the undulatory motion of the dorsal fin to generate thrust, which makes it possess quite high maneuverability and efficiency, and due to its low volume of the dorsal fin, it is conducive to the study of miniaturization of the driving mechanism. This paper carried out a study on the undulatory motion mechanism of the seahorse's dorsal fin and proposed a dynamic model of the interaction between the seahorse's dorsal fin and seawater based on the hydrodynamic properties of seawater and the theory of fluid-structure coupling. A simulation model was established using the Fluent software, and the 3D fluid dynamic mesh was used to study the undulatory motion mechanism of the seahorse's dorsal fin. The effect of the swing frequency, amplitude, and wavelength of the seahorse's dorsal fin on its propulsion performance was studied. On this basis, an optimized design method was used to design a bionic seahorse's dorsal fin undulatory motion mechanism. The paper has important guiding significance for the research and miniaturization of new underwater vehicles. [ABSTRACT FROM AUTHOR]

Water droplet unidirectional adhesion, wetting, and transport on the asymmetric superhydrophobic surfaces have attracted much research interest in theory analyses and applications. In this study, inspired by the butterfly wings and lotus leaf, a novel anisotropic superhydrophobic surface with different tilt angles of the wedge‐shaped structures is prepared on aluminum surfaces via laser ablation inside water. It is demonstrated experimentally that the resistant force of water droplets on the bioinspired surfaces is different along the tilt direction of the wedge‐shaped structure and the inverse direction. The sliding and bouncing behaviors of water droplets on different bioinspired wedge‐shaped structure surfaces are simulated and tested to understand better the mechanism of the rolling and bouncing droplets induced by asymmetric wedge‐shaped structures. Furthermore, the effect of the tilt wedge‐shaped structures on the anisotropic superhydrophobic properties is revealed from the mechanical point of view. The relationship between the anisotropic superhydrophobic properties and the tilt angle of the wedge‐shaped structure is investigated. [ABSTRACT FROM AUTHOR]

The predation behavior of the pistol shrimp is extremely special, and the predation process will produce a huge popping sound, which has caused extensive research by scholars from all over the world. This article carried out a study on the rapid closing jet mechanism of pistol shrimp's claws. A theoretical model, based on the hydrodynamic characteristics of seawater and the theory of fluid-structure coupling, was proposed for the interaction between the claws and seawater. A simulation model was established using the finite volume software Fluent, and the rapid closing jet mechanism of pistol shrimp's claws was verified by using fluid dynamic grid. This article studied the influence of different fluid models on the simulation results. The effects of the claws' closing angular velocity and angular acceleration on the interaction between the claws and seawater were analyzed, which provides a theoretical basis for the development of new underwater kinetic energy weapons. [ABSTRACT FROM AUTHOR]

In the real world, a human tourist can quickly arrive at a target along the route planned by his/her instinctive cognition of prepared maps. While on the mobile robot, it is required to know every way-points of the static or dynamic planning paths to reach a goal point. The previous navigation modes are mostly from sensor location, speech interaction, grid maps and so on. They rely on sensing performance, the speech instruction of site personnel or complex algorithms for the path searching and tracking. For improving the performance of interaction and tele-operated path tracking, in this paper, a novel interactive navigation based on the recognition of hand-drawn paths is proposed for mobile robots. Pen, paper, and camera are employed as the interface between users and the mobile robot. Initially, the image of a hand drawn path in the paper map is captured by a camera and segmented from the background by the color detection model. It is hypothesized that the captured frame of hand-drawn paths is slant to the original orthogonal map. Therefore, this method should firstly project the smoothed skeleton of slant path into the coordinate space of orthogonal map to guide the robot to perform path tracking. Then the hand-drawn path is rectified and remapped into the registered reference image of the orthogonal map through feature matching and perspective transformation. The combination of SIFT and RANSAC algorithms are employed for improving the accuracy of the projection of slant paths in the orthogonal map. Sequentially, a limited number of way-points are picked out from the corrected path in an orthogonal 2D map space usable for 2D navigation. The oriented sequential motion vectors are estimated by linking all successive way-points and employed for the path tracking along the predefined route step by step. Eventually, random navigation paths are designed to validate the robustness, effectiveness and accuracy of the constructed interactive navigation system. [ABSTRACT FROM AUTHOR]

In this paper, an initiative Martian dust fluid simulating research based on the energy dissipation method was developed to simulate the deposition process of Martian dust fluid which was caused by surface adhesion between particles and Martian rovers. Firstly, an energy dissipation model of particles based on the Discrete Element Method (DEM) was established because of the characteristics of Martian dust particles such as tiny size and viscoelasticity. This model is based on the existing DMT model to analyze the collision deposition of dust fluid particles, including particle-spacecraft collision and particle-particle collision. Secondly, this paper analyzed the characteristics of particles after their first collision, then, established the stochastic model of critical wind speed for the particle deposition process. Finally, a series of simulations of the Martian dust fluid particle deposition process were done based on DEM-CFD. The results verified the accuracy of the energy dissipation model and the stochastic model, which could also verify the feasibility and effectiveness of the computing method of Martian dust fluid based on the DEM-CFD technology. [ABSTRACT FROM AUTHOR]

Abstract With the development of ISRU Technology, lunar soil has become an important kind of building material for lunar base. Although the particle shape of lunar soil is extremely irregular, the non-linear mechanical property of lunar soil particles is rarely researched. In this paper, the relationship between the displacement and the contact force of lunar soil particles were researched. First, a series of experiments on normal mechanical properties of lunar soil particles based on the high-precision micro-operation test bed were carried out. Second, a contact model for irregular lunar soil particles was established. The irregular particles are equivalent to spherical particles, and an equivalent algorithm based on piecewise function fitting was proposed. Finally, a series of simulation were carried out to verify the equivalent algorithm in the discrete element method software EDEM. The results provided a solid theoretical basis for the calculation of contact forces between irregularly shaped lunar soil particles. Graphical abstract Unlabelled Image Highlights • Normal mechanical properties of lunar soil particles were tested. • A contact model for irregular lunar soil particles was established. • An equivalent algorithm based on piecewise function fitting was proposed. • Simulations based on EDEM were performed to verify the validity of the theory. [ABSTRACT FROM AUTHOR]

In this paper, the adhesion between irregularly shaped Martian dust particles and the Martian probe in the dust storm is studied. First, the characteristics of irregularly shaped Martian dust particles are analyzed using fractal theory and the discrete element simulation model of irregularly shaped Martian dust particles is built. Second, the mechanical model of the adhesion of Martian dust onto the Martian probe is established, and the analytical solution of the critical wind speed is calculated. Finally, a series of simulations based on DEM-CFD are performed to analyze the creeping of irregularly shaped Martian dust particles in the Martian atmospheric environment. The research can provide a theoretical basis for the processes of dust protection and cleaning in a Martian dust storm. [ABSTRACT FROM AUTHOR]