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Generalized flyby trajectories around elongated minor celestial bodies as a rotating mass dipole

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Acta Mechanica Sinica 2016年第3期32卷 535-545页

作者： xiangyuan zeng Baodong Fang Junfeng Li Yang Yu School of Aerospace Engineering Tsinghua UniversityBeijing 100084 China Shanghai Satellite Engineering Research Institute Shanghai 200240 China Observatoire de la Cote d'Azur 06300 Nice France

The aim of this paper is to understand the common characteristics of the generalized flyby trajectory around natural elongated bodies. Such flyby trajectories provide a short-term mechanism to clear away vicinal objects or temporally capture ejecta into circling orbits. The gravitational potential of elongated bodies is described by a unified approximate model, i.e., the rotating mass dipole which is two point masses connected with a constant massless rod The energy power is used to illustrate the flyby effect in terms of the instantaneous orbital energy. The essential of the single flyby trajectory is studied analytically, and the relationship between the flyby trajectory and its Jacobi integral is also illustrated. Sample trajectories are given to show the variational trend of the energy increment with respect to differen orbital periapsides. The distribution of natural ejecting orbits is presented by varying the parameters of the approximate model.

关键词： Generalized flyby trajectory Natural elongated body Rotating mass dipole Natural ejecting orbits

Attitude-adjusting dynamical behavior of cubic rover on low-gravity testbed

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Astrodynamics 2024年第1期8卷 149-159页

作者： Bowen Jiang Muhammad Talha Hussain xiangyuan zeng School of Automation Beijing Institute of TechnologyBeijing100081China

Cubic rovers that traverse by hopping systems are promising in low-gravity *** several analyses of the control methods and mobility of the cubic rover are available,investigations of its attitude-adjusting behavior are still *** study derives the dynamic equations of the two attitude-adjusting modes of the cubic rover,referred to as walking and *** relationships between the speed threshold and rotation angle of the cubic rover were investigated in both rigid and regolith environments using a self-designed low-gravity *** studies were conducted by considering the experimental and simulated *** results of this study can be interesting for roving mission planning when exploring planetary moons and small celestial bodies.

关键词： low-gravitytestbed attitude-adjusting motion cubic rover experimental study

A comparative assessment of gravitational field modeling methods for binary asteroid landing

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Astrodynamics 2024年第3期8卷 417-435页

作者： Tongge Wen xiangyuan zeng Ziwen Li Yang Yu School of Automation Beijing Institute of TechnologyBeijing100081China School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China

The tradeoff between accuracy and efficiency in gravitational field modeling for binary asteroid landing is one of the challenges in dynamical *** representative gravitational modeling methods are employed and compared in this *** are the sphere-sphere model,ellipsoid-sphere model,inertia integral-polyhedron method,and finite element *** study considers the differences between these four models,particularly their effects on the landing dynamics of a lander.A framework to simulate the coupled orbit-attitude motion of a lander in a binary system is first *** simulations are then performed on the natural landings on the second primary of the(66391)Moshup-Squannit *** results show significant differences in the final landing dispersions,settling time,and sliding distance when applying the simplified *** the basis of the modeling accuracy and computational efficiency,the finite element method should be chosen for future missions.

关键词： landing dynamics contact dynamics gravitational field modeling binary asteroid

Solar sail H-reversal trajectory:A review of its advances and applications

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Astrodynamics 2019年第1期3卷 1-15页

作者： xiangyuan zeng Giovanni Vulpetti Christian Circi School of Automation Beijing Institute of TechnologyBeijing100081China International Academy of Astronautics Paris75116France Sapienza University of Rome Rome00138Italy

The set of the orbital angular-momentum reversal,or H-reversal,sailcraft trajectory was born as a type of unconventional precursor interstellar mission trajectory by using highperformance solar *** from an outline of the H-reversal sail trajectory,this paper mainly focuses on the 2D reversal-mode solution to the general solar-photon sail motion *** feasible region for H-reversal trajectories in fixed sail attitude angles is *** interesting applications of the H-reversal trajectory are presented in detail to show its *** a special case,a precursor interstellar probe can be delivered with a constant sail orientation in the H-reversal trajectory to be compared with the direct-motion sail flyby of the *** importance are the heliocentric periodic orbits in double H-reversal modes,obtained via both fixed and time-varying sail attitude *** more applications involving H-reversal trajectories are discussed in terms of asteroid deflection and transfer trajectory to rectilinear ***,some items of the mathematics behind the 3D motion-reversal trajectories are summarized.

关键词： solar-photon sailing sailcraft lightness number orbital H-reversal mode

Feasibility analysis of the angular momentum reversal trajectory via hodograph method for high performance solar sails

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Science China(Technological Sciences) 2011年第11期54卷 2951-2957页

作者： zeng xiangyuan BAOYIN HeXi LI JunFeng GONG ShengPing School of Aerospace Tsinghua University Beijing 100084 China

In this paper a new phase space of hodograph method is adopted to investigate and better understand the two-dimensional angular momentum reversal(H-reversal) trajectories for high performance solar sails within a fixed cone *** the hodograph method and the H-reversal trajectory are not very common,both of them are briefly *** relationship between them are constructed and addressed with a sample *** the phase space varies according to the sail quality and the fixed sail cone angle is also *** variation of the phase space,the minimum sail lightness number can be obtained by solving a set of algebraic equations instead of a parameter optimization *** a given sail lightness number,there are three types of the two-dimensional possible heliocentric motion,including the spiral inward trajectories towards the Sun,the H-reversal trajectories and the directly outward escape *** boundaries that separate these different groups are easily determined by using the phase ***,the method and procedures to achieve the feasible region of the H-reversal trajectory with required perihelion distance are presented in detail.

关键词： solar sail angular momentum reversal (H-reversal) hodograph method

Age estimation from facial images based on Gabor feature fusion and the CIASO-SA algorithm

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CAAI Transactions on Intelligence Technology 2023年第2期8卷 518-531页

作者： Di Lu Dapeng Wang Kaiyu Zhang xiangyuan zeng School of Measurement and Communication Engineering Harbin University of Science and TechnologyHarbinChina Cheriton School of Computer Science University of WaterlooWaterlooOntarioCanada

Aiming at the problem of long time-consuming and low accuracy of existing age estimation approaches,a new age estimation method using Gabor feature fusion,and an improved atomic search algorithm for feature selection is ***,texture features of five scales and eight directions in the face region are extracted by Gabor wavelet *** statistical histogram is introduced to encode and fuse the directional index with the largest feature value on Gabor ***,a new hybrid feature selection algorithm chaotic improved atom search optimisation with simulated annealing(CIASO-SA)is presented,which is based on an improved atomic search algorithm and the simulated annealing ***,the CIASO-SA algorithm introduces a chaos mechanism during atomic initialisation,significantly improving the convergence speed and accuracy of the ***,a support vector machine(SVM)is used to get classification results of the age *** verify the performance of the proposed algorithm,face images with three resolutions in the Adience dataset are *** the Gabor real part fusion feature at 48�48 resolution,the average accuracy and 1-off accuracy of age classification exhibit a maximum of 60.4%and 85.9%,*** results prove the superiority of the proposed algorithm over the state-of-the-art methods,which is of great referential value for application to the mobile terminals.

关键词： age estimation atom search algorithm feature selection Gabor feature simulated annealing

Periodic orbits in the Chermnykh problem

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Astrodynamics 2017年第1期1卷 41-55页

作者： xiangyuan zeng Kyle T.Alfriend School of Automation Beijing Institute of TechnologyBeijing 100081China Department of Aerospace Engineering Texas A&M UniversityCollege StationTexas 77840USA

Periodic orbits in irregular gravitational fields are significant for an understanding of dynamical behaviors around asteroids as well as the engineering aspect for deep space explorations. The rotating mass dipole, referred to as the Chermnykh problem, is a good alternative model to study qualitative dynamical environments near elongated asteroids, like the asteroid 1620 Geographos, 216 Kleopatra, or 25143 Itokawa. In this paper a global searching method is adopted to search for periodic orbits around the dipole model based on the concept of Poincaré section of surface. Representative families of periodic orbits are illustrated with respect to all three topological cases of the dipole model. Topological transitions of orbits during iso-energetic continuations are also presented as well as identification of new types of periodic orbits.

关键词： periodic orbits the Chermnykh problem topological transition iso-energetic continuation

Finite-Time Control Based On The Time-Varying Sliding Mode For Spacecraft Body-Fixed Hovering Over an Asteroid 36

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Finite-Time Control Based On The Time-Varying Sliding Mode F...

Integrated guidance and control based on high-order sliding mode method 36

第36届中国控制会议

作者： Jinsong Zhao Yongzhi Sheng xiangyuan zeng Zhirong Lei School of Automation Beijing Institute of Technology School of Automation Northwestern Polytechnical University

ISBN: (纸本)9781538629185

This paper investigates a finite time control for spacecraft hovering in highly uncertain dynamical environments,typically found around *** control method is based on the time varying second order sliding mode ***,feedback linearization is exploited to transform the dynamic equations for spacecraft into three independent second order uncertain ***,a simplified model of the natural elongated body is introduced to describe its gravitational *** proposed control scheme for the hovering maneuvers is proved with a stability ***,numerical simulations are performed to evaluate the effectiveness of the proposed control scheme.

关键词： Hovering spacecraft Finite-time convergence High-order sliding mode Chattering alleviation Sliding mode control

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Integrated guidance and control based on high-order sliding ...