排序方式: 共有306条查询结果,搜索用时 15 毫秒
141.
The tracking control problem for Flexible Joint Manipulator Control System(FJMCS)with unmeasurable states is addressed in this paper. Firstly, a High-Gain Observer(HGO) is constructed to estimate the unmeasurable states and the uncertainties. Then, a Dynamic Surface Control(DSC) scheme is developed by using the estimation of HGO. The newly proposed controller has two advantages over the existing methods:(A) a novel Spike Suppression Function(SSF) is developed to avoid the estimation spike proble... 相似文献
142.
The Strategic Priority Program on Space Science in 2011-2017 (hereafter referred to as SPP I), which officially went ahead in 2011, marks that a new chapter of Chinese space endeavor has been opened. The 4 satellites, Wukong/DAMPE, SJ-10, Mozi/QUESS and Insight/HXMT, has been achieving promising scientific results since their launch, e.g., Wukong directly detected a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons. To enable the sustainable development of China's space science endeavor, the Strategic Priority Program Ⅱ on Space Science (hereafter referred to as SPP Ⅱ) was officially approved in late 2017. SPP Ⅱ includes 4 satellites-EP, ASO-S, SMILE and GECAM, Intensive Study of Future Space Science Missions, Advanced Research of Space Science Missions and Payloads, Space Science Mission Concept Research, and Data Analysis Research. Dedicated to exploring the unknown, the program is aiming to address scientific questions such as the origin and evolution of the universe and life, search for extraterrestrial life, and the impact of the Sun and the solar system on Earth and human development. Chinese space science community is committed to contributing to the progress of human civilization. 相似文献
143.
The Chinese Meridian Space Weather Monitoring Project (Meridian Project) is a ground-based geospace monitoring chain in China. It consists of 15 ground-based observation stations located roughly along 120°E longitude and 30°N latitude. In recent two years, using data from the Meridian Project, significant progress has been made in space weather and space physics research. These advances are mainly in four aspects:regional characteristics of space environment above China or along 120°E meridian line, coupling between space spheres at different heights and different physical processes, space weather disturbance and its propagation along the meridian chain, and space weather effects on ground technical facilities. 相似文献
144.
Progress of Solar Wind Magnetosphere Ionosphere Link Explorer(SMILE) Mission 总被引:1,自引:1,他引:0 下载免费PDF全文
SMILE (Solar wind Magnetosphere Ionosphere Link Explorer) mission is a joint ESA-CAS space science project. The working orbit is a 19 Re 5000 km HEO with 4 scientific instruments:Soft X-ray Imager(SXI), Ultra-Violet Imager (UVI), Magnetometer (MAG) and Light Ion Analyzer (LIA). SMILE aims to understand the interaction between the solar wind and the Earth's magnetosphere through the images of SXI and UVI and in-situ measurement from LIA and MAG. After the kick-off in 2016, the SMILE project went to Phase A study. The mission adoption is scheduled for November 2018, with a target launch date in 2022-2023. In this paper, the background of the mission, scientific objectives, the design and characteristics of scientific instruments and the mission outline will be introduced in details. 相似文献
145.
During the past two years (2016-2018), great achievements have been made in the Chinese research of interplanetary physics, with nearly 100 papers published in the academic journals. The achievements are including but not limited to the following topics:solar corona; solar wind and turbulence; filament/prominence and jets; solar flare; radio bursts; particle acceleration at coronal shocks; magnetic flux ropes; instability; instrument; Coronal Mass Ejections (CMEs) and their interplanetary counterparts; Magnetohydrodynamic (MHD) numerical modeling; solar energetic particles and cosmic rays. The progress further improves our understanding of the eruptions of solar activities, their evolutions and propagations in the heliosphere, and final geoeffects on our Earth. These results were achieved by the Chinese solar and space scientists independently or via international collaborations. This paper will give a brief review of these achievements. 相似文献
146.
Application of ERA5 Reanalysis to the Construction of Initial Conditions for WACCM Simulations 总被引:1,自引:1,他引:0 下载免费PDF全文
WANG Yegui JING Wenqi CUI Yuanyuan CAI Qifa LAN Weiren FANG Hanxian WENG Libin NIU Jun 《空间科学学报》2018,38(4):460-468
This study uses ECMWF fifth-generation reanalysis, ERA5, which extends to the mesopause, to construct the Initial Conditions (IC) for WACCM (Whole Atmosphere Community Climate Model) simulations. Because the biases between ERA5 and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature data are within ±5 K below the lower mesosphere, ERA5 reanalysis is used to construct IC in the lower atmosphere. Four experiments are performed to simulate a Stratospheric Sudden Warming (SSW) event from 5 to 15 February 2016. The simulation using the WACCM default climatic IC cannot represent the sharp meteorological variation during SSW. In contrast, the 0~4 d forecast results driven by ERA5-constructed IC is consistent with ERA5 reanalysis below the middle mesosphere. Comparing with WACCM climatology ICs scheme, the ICs constructing method based on ERA5 reanalysis can obtain 67%, 40%, 22%, 4% and 6% reduction of temperature forecast RMSE at 10 hPa, 1 hPa, 0.1 hPa, 0.01 hPa and 0.001 hPa respectively. However, such improvement is not shown in the lower thermosphere. 相似文献
147.
Gongyu WANG Shulei YAO Yuxin CHI Chengcheng ZHANG Ning WANG Yalong CHEN Rongsheng LU Zhuang LI Xiancheng ZHANG 《中国航空学报》2024,(1):377-390
Submerged abrasive waterjet peening(SAWJP) is an effective anti-fatigue manufacturing technology that is widely used to strengthen aeroengine components. This study investigated the correlation of SAWJP process parameters on surface integrity and fatigue life of titanium alloy TA19. SAWJP with different water pressures and standoff distances(SoDs) was conducted on the TA19 specimens. The surface integrity of the specimens before and after SAWJP with different process parameters was experimentall... 相似文献
148.
The large manipulator outside the space cabin is a multi-degree of freedom actuator for space operations. In order to realize the automatic control and flexible operation of the space manipulator, a novel spoke structure piezoelectric six-dimensional force/torque sensor with redundancy ability, high stiffness and good decoupling performance is innovatively proposed. Based on the deformation coordination relationship, the redundancy measurement mechanism is revealed.The mathematical models of the... 相似文献
149.
Jian QIU Maliya HEINI Jusha MA Wenjia HAN Xunchun WANG Jun YIN Yan SHI Cunfa GAO 《中国航空学报》2024,(1):173-185
During long-term service in space, Gallium Arsenide(GaAs) solar cells are directly exposed to electron irradiation which usually causes a dramatic decrease in their performance. In the multilayer structure of solar cells, the germanium(Ge) layer occupies the majority of the thickness as the substrate. Due to the intrinsic brittleness of semiconductor material, there exist various defects during the preparation and assembly of solar cells, the influences of which tend to be intensified by the irr... 相似文献
150.
During the whole service lifetime of aircraft structures with composite materials, impacts are inevitable and can usually cause severe but barely visible damages. Since the occurrences of impact are random and unpredictable, it is a hotspot direction to develop an online impact monitoring system that can meet strict limitations of aerospace applications including small size, light weight, and low power consumption. Piezoelectric(PZT) sensor, being able to generate impact response signals with no... 相似文献