Modular truss space deployable antennas are key for future large aperture, high precision antennas, already proven in various in-orbit applications globally. This paper introduces a design method for a tetrahedral basic unit mechanism with dual height positioning nodes. A parametric model is established, and its DOF are analyzed to confirm the mechanism’s validity. The new tetrahedral basic unit mechanism constructed by this method is a single DOF mechanism and can locate different parabolic node heights. In order to further adapt to the parabolic and large aperture requirements of the deployable antenna of the truss, a combination unit and modular unit mechanism are developed based on this tetrahedral unit. The DOF and deployment characteristics of the modular unit mechanism are analyzed and validated through simulations. Various networking methods for the modular units are proposed, followed by a comprehensive performance comparison of different modular truss deployable antenna mechanisms. A prototype model of the modular unit mechanism is also developed, with deployment experiments demonstrating the mechanism’s simplicity, low DOF, and large deployment ratio. The findings of this study provide a theoretical and technical basis for the future design and development of truss deployable antenna mechanisms.

With the development of the aerospace industry, space missions are becoming more complicated and diversified, and there is a demand for antenna mechanisms with a larger physical aperture. In this paper, a planar deployable mechanism is proposed, which can form a flat reflection surface with a small gap between plates. To this end, a novel large-scale two-dimensional deployable nine-grid planar antenna mechanism is designed. First, two antenna folding schemes and four supporting mechanism schemes are proposed. Through comparison analysis, the antenna configuration scheme with the best comprehensive performance is selected. A kinematic model of the deployable mechanism is established, and its kinematic characteristics are analyzed. Then, the correctness of the kinematic model is verified by comparing the analytical and simulation results of the kinematic model. Subsequently, a finite element model of the antenna is developed. Based on the response surface method, the structural parameters of the support rods of the antenna are optimized, and a set of optimized solutions with lightweight and high fundamental frequency characteristics are obtained. Finally, a prototype of the proposed nine-grid planar antenna is fabricated. The feasibility of the deployment principle and the rationality of the designed mechanism are verified by deployment experiments.

Currently, manual detection of wall welds and surface microcracks on ships and oil tanks is not only inefficient but also potentially hazardous. This study proposes a 4SRRR legged wall-climbing robot with redundant actuation, designed to accommodate the characteristics of permeable materials, to address this issue. First, the robot's gait is examined, followed by a thorough examination of its stability on both vertical and horizontal surfaces. For vertical surfaces, a statics analysis is conducted to prevent the risk of falling, whereas, for horizontal surfaces, the margin of stability is evaluated. To determine the required degrees of freedom for the robot to complete its assigned tasks, the screw theory is applied. The De-navit-Hartenberg (D-H) method is then used to analyze the forward and inverse kinematics of the robot. In addition, the La-grange balance method is used to analyze the swing leg's dynamics. A control algorithm for impedance is developed for situations in which the swinging leg collides with the ground. A prototype is then designed and tested to assess the wall-climbing performance and the efficacy of the impedance control strategy when the swinging leg experiences an impact. This research seeks to provide a solid theoretical foundation and technical support for the engineering application of wall-climbing robots, thereby enhancing the efficiency and safety of wall weld and surface microcrack detection processes in ships and oil tanks.