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Study on the Behavior of Solar Array Deployment with Root Hinge Drive Assembly

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Chinese Journal of Aeronautics 2012年第2期25卷 276-284页

作者： DING Xilun LI Xin XU Kun YANG Qiaolong PU Hailing Robotics Institute Beihang University Beijing 100191 China beijing Institute of spacecraft system engineering Beijing 100094 China

In this paper, a method of using a root hinge drive assembly （RHDA） to control the solar array deployment is provided and a multi-DOF mechanism dynamic model of the system is established. In this way, the root hinge torque can be calculated iteratively. Then taking the predicted torque as a reference, a RHDA is designed for a large multiple-stage packaging and deployable solar array system. The control effect of the drive assembly is validated by ground tests. The test results indicate that the solar arrays can be deployed smoothly, and the deployment velocities are restricted by the drive assembly as expected. During the tests, the RHDA output speed and output torque are obtained. In order to examine the impact force when the yoke is lock-up with a hard stop, dynamics simulations are performed according to the actual behavior. The simulation result indicates that the designed RHDA reduces the impact force significantly and improves the lock-up reliability effectively.

关键词： solar array root hinge drive assembly multi-DOF model dynamics simulation reliability lock-up

Experimental Studies on Condensation Heat Transferof the Moist Air outside the Horizontal Circular Pipe witha Porous Layer

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Journal of Thermal Science 1999年第2期8卷 108-113页

作者： Liu Qiang Zhang Jiaxun Zhong Qi(Beting Institute of spacecraft system engineering, R.O. Box 9628-5, beijing 100086, China) beijing Institute of spacecraft system engineering Beijing China

This paper presents the structure design of four kinds of circular pipes with porous layer and the experimental resultsof condensation heat transfer of the moist air outSide the horizontal choular pipes. By comparison with theexperiments on bare Pipes, it is concluded that, the designed pipes not only have good condensation heattransfer Performance, but also have the ability to collect and remove condensed liquid under zero gravity. They canbe aPPlied to the thermal control system for future large spacecraft.

关键词： condensation capillary wick convection

Precipitate Characteristics and Mechanical Performance of Cast Mg–6RE–1Zn–xCa–0.3Zr(x=0 and 0.4 wt%) Alloys

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Acta Metallurgica Sinica(English Letters) 2022年第4期35卷 596-608页

作者： Zijian Yu Xi Xu Baotian Du Kang Shi Ke Liu Shubo Li Xiuzhu Han Tao Xiao Wenbo Du College of Materials Science and engineering Beijing University of TechnologyBeijing 100124China beijing Institute of spacecraft system engineering Beijing 100094China

In this study,the Mg–4Y–1Gd–1Nd–xCa–1Zn–0.3Zr(x=0 and 0.4 wt%)cast alloys with low rare earth concentration were prepared in different routes of heat treatments,and their microstructures and mechanical properties were *** Mg–4Y–1Gd–1Nd–1Zn–0.4Ca–0.3Zr cast alloy with ultimate tensile strength(UTS)of 264±7.8 MPa,tensile yield strength(TYS)of 153±1.2 MPa and elongation to failure(EL)of 17.2±1.2% was successfully developed by appropriate heat *** improved mechanical performance was attributed to the combined strengthening effects of fine grains,Mg24RE5,β′,β_(1),γ′and LPSO *** the heat treatment process,cooling method of T4 treatment affected the microstructure,which consequently determined the mechanical properties air cooling,rather than water cooling,gave rise to the formation of γ′phase in the alloy without Ca ***,Ca addition facilitated the formation of γ′phase,and the γ′phase precipitated in the alloy after T4 treatment either by water cooling or by air cooling,but the air cooling increased the number density of γ′phase in comparison to the water *** the γ′phase strengthened the studied alloys,the formation of γ′phase inhibited the precipitatition of β′and β_(1) phases in the following T6 treatment,and consequently reduced the strengthening effect ofβ′andβ_(1) *** results showed that the mechanical performance of the studied alloys was largely determined by the precipitation of γ′phase,which was regulated by the Ca addition and the cooling method of T4 treatment.

关键词： Magnesium alloy Microstructure Mechanical properties Rare earth Heat treatment

A solution using only electromagnetic coils for relative pose control in satellite docking

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Chinese Journal of Aeronautics 2024年第3期37卷 258-281页

作者： Guangzheng RUAN Lijian WU Bo WANG Yaobing WANG Runqi HAN College of Electrical engineering Zhejiang UniversityHangzhou 310012China beijing Institute of spacecraft system engineering Beijing 100094China

This paper proposes an electromagnetic coil topology and its control strategy,which can be incorporated into the electromagnetic docking device to achieve relative pose control in satellite *** target satellite has a main coil;the chaser satellite possesses a main coil of the same size accompanied by six and four evenly arranged secondary coils inside and outside the main coil,*** coil on the target satellite is DC energized,while the currents in the coils of the chaser satellite are *** remove the coupling between the pitch/yaw torque and translational force,the internal and external secondary coils of the chaser satellite interact with the main coil of the target satellite to perform the control of relative pitch/yaw and relative translation,respectively,so relative pose control can be *** torque and force vectors exerted by the secondary coils of the chaser satellite are synthesized onto the pitch and yaw axes of the body *** to their spatial composition relationship,the formulas are proposed,which obtain the magnetic moment vectors of the coils from the set torques and *** controllers regulating pitch/yaw,translation,and distance utilize a three-loop cascaded structure that consists of an outer position loop,a middle velocity loop and an inner current *** control strategy is verified by dynamics simulation.

关键词： Electromagnetic docking 6 degree of freedom Relative pose control Coil array Far field model Motion decoupling

An overview of the mission and technical characteristics of Change'4 Lunar Probe

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Science China(Technological Sciences) 2017年第5期60卷 658-667页

作者： YE PeiJian SUN ZeZhou ZHANG He LI Fei China Academy of Space Technology Beijing 100094 China Institute of spacecraft system engineering Beijing 100094 China

Change＇4 Lunar Probe will softly land on the farside of the Moon for the first time of all mankind and carry out in-situ and rovering exploration. In this paper, the scientific significance and engineering difficulties of Change＇4 are introduced and the probe＇s general design, including the aspects of landing site selection, relay communication, trajectory design of relay satellite is explained. Besides, four key technologies, namely safe landing strategy on complex terrain, orbit design and control of libration point 2, relay communication on L2, radioisotope thermoelectric generator （RTG） and electric-thermal utilization, as well as how to realize them are also discussed. Finally the prospect of the prominent technological breakthrough of Change＇4 is described.

关键词： Change'4 farside relay communication libration point South-Pole Aitken Basin RTG

Mission overview and key technologies of the first Mars probe of China

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Science China(Technological Sciences) 2017年第5期60卷 649-657页

作者： YE PeiJian SUN ZeZhou RAO Wei MENG LinZhi China Academy of Space Technology Beijing 100094 China Institute of spacecraft system engineering Beijing 100094 China

The first Chinese Mars exploration will fulfill the goals of ＂orbiting, landing and roving＂ in one mission. This paper briefly describes the process of international Mars exploration and analyzes the development of Chinese Mars exploration. It focuses on introducing the scientific significance and engineering difficulties of Mars exploration, and provides an overview of the system design of the probe, including the flight profile, the preliminary selection of the landing site, the entry, descent and landing （also known as EDL） process. Four types of key technologies, including telecommunications, autonomous control, the EDL process, and its structure and mechanism, are detailed in this paper. Finally, the paper highlights the expected scientific and engineering results of the mission.

关键词： Mars mission key technologies China

NECESSARY AND SUFFICIENT BOUNDARY INTEGRAL EQUATIONS FOR PLANE HARMONIC FUNCTIONS

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Science China Mathematics 1992年第7期35卷 861-869页

作者：胡海昌 Chinese Institute of spacecraft system engineering Beijing 100086 PRC

It is discovered that the customary boundary integral equations for plane harmonic functions are neither necessary nor sufficient. This is due to a misunderstanding that a boundary integral representation not covering all plane harmonic functions is regarded as such. This representation is modified in the present paper to cover all plane harmonic functions. Then two necessary and sufficient boundary integral equations, one with direct and the other with indirect unknowns, are established.

关键词： boundary value problem of harmonic function boundary integral equation boundary element method.

Relative roll control of satellite docking using electromagnetic coils

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Chinese Journal of Aeronautics 2023年第12期36卷 361-374页

作者： Lijian WU Guangzheng RUAN Runqi HAN Bo WANG Yaobing WANG College of Electrical engineering Zhejiang UniversityHangzhou 310012China beijing Institute of spacecraft system engineering Beijing 100094China

An electromagnetic coil topology and its control strategy,which can be incorporated into the electromagnetic docking device,have been proposed for the relative roll control of two satellites in *** target satellite and the chaser satellite are respectively embarked with four and six coils evenly arranged around the docking *** the coils on the target satellite are Direct Current(DC)energized,while the currents in the coils of the chaser satellite are regulated to achieve the relative roll *** electromagnetic force/torque model is built by utilizing the frequentlyused far field *** on the fundamental components extracted from that model,this paper proposes a real-time magnetic moment vector distribution formula that simply generates a constant roll *** paper not only presents an equation for calculating the relative roll angle through the Euler angles of two satellites,but also an equation that converts the roll torque setpoint to the setpoints of the coil currents.A 3-closed-loop positioning controller composed of angle,angular velocity,and current loop is *** proposed topology is verified by finite element simulation,and the control strategy is validated by dynamics simulation and ground-based tests.

关键词： Coil array Electromagnetic docking Electromagnets Far field model Force/torque model Relative roll control

Microstructure,Texture Evolution,and Strain Hardening Behaviour of As-extruded Mg-Zn and Mg-Y Alloys under Compression

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Journal of Wuhan University of Technology(Materials Science) 2023年第2期38卷 430-439页

作者： HAN Xiuzhu XIAO Tao YU Zijian beijing Institute of spacecraft system engineering Beijing100094China Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing100124China

Microstructure,texture evolution and strain hardening behaviour of the Mg-1Y and Mg-1Zn(wt%)alloys were investigated under room temperature *** characterization was performed by optical microscopy,scanning electron microscopy,electron back scattered diffraction and transmission electron *** experimental results show that Mg-1Zn alloy exhibits conventional three-stage strain hardening curves,while Mg-1Y alloy exhibits novel six-stage strain hardening *** Mg-1Y alloy,rare earth texture leads to weak tensile twinning activity in compression and consequently results in a moderate evolution to***,inefficient tensile twinning activity and weak slip-twinning interaction give rise to excellent ductility and high hardening capacity but low strain hardening *** Mg-1Zn alloy,basal texture leads to pronounced tensile twinning activity in compression and consequently results in rapid evolution to*** intense tensile twinning activity and strong slip-twinning interaction lead to high strain hardening rate but poor ductility and low hardening capacity.

关键词： magnesium alloy texture rare earth twinning strain hardening behavior