Dynamic Characteristic Analysis of Large Space Deployable Articulated Mast

AbstractEquivalent continuum beam model and finite element model of space deployable articulated mast are developed. Dynamic characteristics of the mast without and with tip load are analyzed based on two models respectively. Frequencies and mode shapes of the mast are calculated and simulated by Euler beam theory and finite element simulation, and theoretical solutions are compared with simulation results. Influence of mast structural parameters on mast natural frequencies is analyzed, the sensitivities of mast bending, torsional, axial frequencies to structural parameters are calculated. The measure for improving mast dynamic characteristic is proposed through sensitivity analysis

Intelligent Drilling and Coring Technologies for Unmanned Interplanetary Exploration

The robotic technology, especially the intelligent robotics that can autonomously conduct numerous dangerous and uncertain tasks, has been widely applied to planetary explorations. Similar to terrestrial mining, before landing on planets or building planetary constructions, a drilling and coring activity should be first conducted to investigate the in-situ geological information. Given the technical advantages of unmanned robotics, utilizing an autonomous drill tool to acquire the planetary soil sample may be the most reliable and cost-effective solution. However, due to several unique challenges existed in unmanned drilling and coring activities, such as long-distance time delay, uncertain drilling formations, limited sensor resources, etc., it is indeed necessary to conduct researches to improve system’s adaptability to the complicated geological formations. Taking drill tool’s power consumption and soil’s coring morphology into account, this chapter proposed a drilling and coring characteristics online monitoring method to investigate suitable drilling parameters for different formations. Meanwhile, by applying pattern recognition techniques to classify different types of potential soil or rocks, a drillability classification model is built accurately to identify the current drilling formation. By combining suitable drilling parameters with the recognized drillability levels, a closed-loop drilling strategy is established finally, which can be applied to future interplanetary exploration

New Protections for Healthcare Workers

<p>Supplemental material, Video 1: sj-vid-1-pic-10.1177 0954406218779612 for Self-adaptive grasp analysis of a novel under-actuated cable-truss robotic finger by Shangling Qiao, Hongwei Guo, Rongqiang Liu, Yong Huang and Zongquan Deng in Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science</p

Design and Dynamic Equivalent Modeling of Double-Layer Hoop Deployable Antenna

This study proposes deployable units driven by elastic hinges and a double-layer hoop deployable antenna composed of these units. A rational modeling method based on the energy equivalence principle is presented to develop an equivalent model of the double-layer hoop antenna in accordance with the structural characteristics of the antenna. The equivalent beam models of the rods with elastic hinges are proposed. The relationship of geometrical and material parameters is established considering the strain energy and the kinetic energy of the periodic unit, which are the same as those of the equivalent beam in the same displacement field. The equivalent model of the antenna is obtained by assembling several equivalent beam models in the circumferential direction. The precision of the equivalent model of the antenna is acceptable as found by comparing the modal analysis results obtained through equivalent model calculation, finite element simulation, and modal test