Search

The problem of lunar interferometric synthetic aperture radar (InSAR) satellite formation configuration design is studied. Firstly, the relative dynamic model of lunar InSAR satellite based on relative eccentricity/inclination (E/I) vector is established. Then, the long-term stable flight conditions of formation flying under the perturbation environment of lunar orbit are studied. Taking the relative altimetry accuracy and fuzzy altitude as optimization indexes, and considering the inter-satellite safety, the objective function of formation configuration design is given. In response to the existing research methods are unable to solve the multi-objective problem of configuration design, an improved multi-objective ant-lion optimization algorithm in applied to achieve the configuration design of lunar InSAR satellite formations. Simulation results show that the proposed algorithm in better in baseline utilization rate, which verities the adaptability and effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

As cast and extruded 6063 aluminum alloy containing rare earth Y was prepared and anodized. The morphology of the anodic oxide film of the alloy was studied and its effect on the hardness and corrosion resistance of the alloy was analyzed. The results showed that compared with ordinary 6063 aluminum alloy, the oxide film of 6063 aluminum alloy modified by rare earth Y has dense surface, no defects and is closely combined with the matrix, and the corresponding surface roughness Sa value is the smallest. The chemical composition of anodic oxide film is mainly alumina, which can significantly improve the surface microhardness of the alloy. After coating, the self- corrosion potential of extruded rare earth Y modified 6063 aluminum alloy is corrected, the self-corrosion current deny is small, the total impedance value is high, and it shows the characteristics of capacitive arc resistance n high frequency region, and the corrosion resistance is better. [ABSTRACT FROM AUTHOR]

The issue of robust actuator fault reconstruction for a class of Takagi‐Sugeno (T‐S) fuzzy systems with actuator fault and unknown input via a novel Synthesized Learning and Sliding‐Mode Observer (SLSMO) is investigated in this paper. Through a coordinate transformation technique, the considered T‐S fuzzy system is decomposed into two separate subsystems: Subsystem 1 affected only by actuator fault and Subsystem 2 affected by unknown input and actuator fault. In the SLSMO methodology, for Subsystem 1, a new reduced‐order Fuzzy Learning Observer (FLO) is explored to accurately reconstruct actuator fault, while a reduced‐order Fuzzy Sliding Mode Observer (FSMO) is employed for Subsystem 2 such that it has strong robustness against actuator fault and unknown input. Stability and convergence of the fuzzy SLSMO are explicitly proved using Lyapunov's indirect method. The design issue of the reduced‐order FLO and of the reduced‐order FSMO can be uniformly formulated in terms of some Linear Matrix Inequalities (LMIs) that can be directly solved using LMI optimization technique. In addition, a new full‐order FLO is suggested for actuator fault reconstruction in a class of T‐S fuzzy system without unknown input. At the end, a numerical example is applied to verify the effectiveness and superiority of the proposed approaches. [ABSTRACT FROM AUTHOR]

This Special Issue aims to highlight the state-of-the-art techniques that are used for advanced fault diagnosis and the fault-tolerant control technology of spacecraft, especially for intelligent fault diagnosis algorithm development and sliding mode fault-tolerant control. Therefore, alongside recent developments in various learning algorithms, advanced observer design, intelligent control, etc., the application of advanced fault diagnosis and FTC techniques to single complicated spacecrafts or distributed spacecraft systems (spacecraft formation flying system, spacecraft cluster, etc.) will be extensively investigated in this Special Issue. In order to complete the various tasks in advanced space missions, such as communication, navigation, and remote sensing, single complicated spacecraft and many distributed spacecraft systems have been launched into orbit. [Extracted from the article]

With growing global concern for mainstreaming of environmental protection measures, the promotion of climate change and sustainable development policies, the international community, represented by international organizations, research institutions, and world‐wide businesses, has focused on green finance. Existing research on green finance in the context of environmental trends has been reviewed in terms of the products and determinants of green finance. This study aims to assess the impact of green finance on the decarbonization of economies in the context of a review of current and potential problems and prospects. Based on the examples of the People's Republic of China, the Russian Federation, and the United States of America, the study suggests that today green finance has not yet demonstrated a tangible effect in these countries. Based on the results of the study, it can be argued that in the three countries, the main tool of green finance in the field of decarbonization is green bonds; other types of green finance are used to a limited extent. The progress of the United States and China is not so obvious, but based on the overall involvement of relevant government agencies and businesses in the green bond market, it can be assumed that the results will be observed in the near future. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of integrated fault reconstruction and fault-tolerant control in linear systems subject to actuator faults via learning observers (LOs). A reconfigurable fault-tolerant controller is designed based on the constructed LO to compensate for the influence of actuator faults by stabilising the closed-loop system. An integrated design of the proposed LO and the fault-tolerant controller is explored such that their performance can be simultaneously considered and their coupling problem can be effectively solved. In addition, such an integrated design is formulated in terms of linear matrix inequalities (LMIs) that can be conveniently solved in a unified framework using LMI optimisation technique. At last, simulation studies on a micro-satellite attitude control system are provided to verify the effectiveness of the proposed approach. [ABSTRACT FROM PUBLISHER]