Xiaowei Shao, Mingxuan Song, Jihe Wang, Dexin Zhang and Junli Chen
The purpose of this paper is to present a method to achieve small satellite formation keeping operations by using the differential lift and drag to control the drift caused by J2…
Abstract
Purpose
The purpose of this paper is to present a method to achieve small satellite formation keeping operations by using the differential lift and drag to control the drift caused by J2 perturbation in circular or near-circular low earth orbits (LEOs).
Design/methodology/approach
Each spacecraft is equipped with five large flat plates, which can be controlled to generate differential accelerations. The aerodynamic lift and drag acting on a flat plate is calculated by the kinetic theory. To maintain the formation within tracking error bounds in the presence of J2 perturbation, a nonlinear Lyapunov-based feedback control law is designed.
Findings
Simulation results demonstrate that the proposed method is efficient for the satellite formation keeping and better accuracy advantage in comparison with classical approaches via the fixed maximum differential aerodynamic acceleration.
Research limitations/implications
Because the aerodynamic force will reduce drastically as the orbital altitude increases, the formation keeping control strategy for small satellites presented in this paper should be limited to the scenarios when satellites are in LEO.
Practical implications
The formation keeping control method in this paper can be applied to solve satellite formation keeping problem for small satellites in LEO.
Originality/value
This paper proposes a Lyapunov control strategy for satellite formation keeping considering both lift and drag forces, and simulation results show better performance with high accuracy under J2 perturbation.
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Keywords
Weijia Lu, Chengxi Zhang, Fei Liu, Jin Wu, Jihe Wang and Lining Tan
This paper aims to investigate the relative translational control for multiple spacecraft formation flying. This paper proposes an engineering-friendly, structurally simple, fast…
Abstract
Purpose
This paper aims to investigate the relative translational control for multiple spacecraft formation flying. This paper proposes an engineering-friendly, structurally simple, fast and model-free control algorithm.
Design/methodology/approach
This paper proposes a tanh-type self-learning control (SLC) approach with variable learning intensity (VLI) to guarantee global convergence of the tracking error. This control algorithm utilizes the controller's previous control information in addition to the current system state information and avoids complicating the control structure.
Findings
The proposed approach is model-free and can obtain the control law without accurate modeling of the spacecraft formation dynamics. The tanh function can tune the magnitude of the learning intensity to reduce the control saturation behavior when the tracking error is large.
Practical implications
This algorithm is model-free, robust to perturbations such as disturbances and system uncertainties, and has a simple structure that is very conducive to engineering applications.
Originality/value
This paper verified the control performance of the proposed algorithm for spacecraft formation in the presence of disturbances by simulation and achieved high steady-state accuracy and response speed over comparisons.
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Jihe Wang, Dexin Zhang, GuoZhong Chen and Xiaowei Shao
The purpose of this paper is to propose a new fuel-balanced formation keeping reference trajectories planning method based on selecting the virtual reference center(VRC) in a…
Abstract
Purpose
The purpose of this paper is to propose a new fuel-balanced formation keeping reference trajectories planning method based on selecting the virtual reference center(VRC) in a fuel-balanced sense in terms of relative eccentricity and inclination vectors (E/I vectors).
Design/methodology/approach
By using the geometrical intuitive relative E/I vectors theory, the fuel-balanced VRC selection problem is reformulated as the geometrical problem to find the optimal point to equalize the distances between the VRC and the points determined by the relative E/I vectors of satellites in relative E/I vectors plane, which is solved by nonlinear programming method.
Findings
Numerical simulations demonstrate that the new proposed fuel-balanced formation keeping strategy is valid, and the new method achieves better fuel-balanced performance than the traditional method, which keeps formation with respect to geometrical formation center.
Research limitations/implications
The new fuel-balanced formation keeping reference trajectories planning method is valid for formation flying mission whose member satellite is in circular or near circular orbit in J2 perturbed orbit environment.
Practical implications
The new fuel-balanced formation keeping reference trajectories planning method can be used to solve formation flying keeping problem, which involves multiple satellites in the formation.
Originality/value
The fuel-balanced reference trajectories planning problem is reformulated as a geometrical problem, which can provide insightful way to understand the dynamic nature of the fuel-balanced reference trajectories planning issue.
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Keywords
Yaquan Han, Jihe Wang, Haifeng Huang, Jun Sun and Yue Sun
This study aims to establish the laser links between satellites among large-scale distributed satellite systems; a combined attitude control strategy containing two stages is…
Abstract
Purpose
This study aims to establish the laser links between satellites among large-scale distributed satellite systems; a combined attitude control strategy containing two stages is proposed in this paper.
Design/methodology/approach
These two stages are: one is the attitude initial pointing control to change the attitude of satellite pointing to the other satellite based on the position information of each satellite; the other one is the high precision attitude tracking control to scan the uncertainty cone because the initial pointing control accuracy is not enough to establish the laser link. At the initial pointing control stage, a method to determine the target attitude of each satellite is presented based on the position information of each satellite, and the fuzzy adaptive control algorithm is used to control the satellites to its calculated attitude. Then, at the high precision attitude tracking control stage, a strategy for laser link acquisition and scanning the uncertainty cone by the lasers of the spacecraft is proposed, and an angular velocity tracking scanning controller is designed while the convergence of the attitude tracking error is ensured through Lyapunov–Krasovskii theory.
Findings
Simulations are conducted to verify the effectiveness of the proposed control algorithm, and the laser link for a large-scale distributed satellite system with super long distance is achieved through a combined attitude control strategy.
Research limitations/implications
A combined attitude control strategy is valid for a large-scale distributed satellite system with super long distance.
Practical implications
A combined attitude control strategy can be used to achieve laser link acquisition for a large-scale distributed satellite system like space gravitational wave detection.
Originality/value
A combined attitude control strategy can provide a way to solve the typical problem that pointing control accuracy is not enough to establish the laser link for a large-scale distributed satellite system.
Details
Keywords
Xiaowei Shao, Jihe Wang, Dexin Zhang and Junli Chen
The purpose of this paper is to propose a modified fuel-balanced formation keeping strategy based on actively rotating satellites in the formation in the J2 perturbed environment.
Abstract
Purpose
The purpose of this paper is to propose a modified fuel-balanced formation keeping strategy based on actively rotating satellites in the formation in the J2 perturbed environment.
Design/methodology/approach
Based on the relative orbital elements theory, the J2 perturbed relative motions between different satellites in the formation are analyzed, and then, the method to estimate fuel required to keep the in-plane and out-of-plane relative motions is presented, based on which a modified fuel-balanced formation keeping strategy is derived by considering both in-plane and out-of-plane J2 perturbations.
Findings
Numerical simulations demonstrate that the modified fuel-balanced formation keeping strategy is valid, and the modified fuel-balanced formation keeping strategy requires less total fuel consumption than original Vadali and Alfriend’s method.
Research limitations/implications
The modified fuel-balanced formation keeping strategy is valid for formation flying mission whose member satellite is in circular or near-circular orbit.
Practical implications
The modified fuel-balanced formation keeping strategy can be used to solve formation flying keeping problem, which involves multiple satellites in the formation.
Originality/value
The modified fuel-balanced formation keeping strategy is proposed by considering both in-plane and out-of-plane J2 perturbations, which further reduce the fuel consumption than the original Vadali and Alfriend’s method.
Details
Keywords
Wenjing Zhu, Dexin Zhang, Jihe Wang and Xiaowei Shao
The purpose of this paper is to present a novel high-precision relative navigation method for tight formation-keeping based on thrust on-line identification.
Abstract
Purpose
The purpose of this paper is to present a novel high-precision relative navigation method for tight formation-keeping based on thrust on-line identification.
Design/methodology/approach
Considering that thrust acceleration cannot be measured directly, an on-line identification method of thrust acceleration is explored via the estimated acceleration of major space perturbation and the inter-satellite relative states obtained from space-borne acceleration sensors; then, an effective identification model is designed to reconstruct thrust acceleration. Based on the identified thrust acceleration, relative orbit dynamics for tight formation-keeping is established. Further, using global positioning system (GPS) measurement information, a modified extended Kalman filter (EKF) is suggested to obtain the inter-satellite relative position and relative velocity.
Findings
Compared with the normal EKF and the adaptive robust EKF, the proposed modified EKF has better estimation accuracy in radial and along-track directions because of accurate compensation of thrust acceleration. Meanwhile, high-precision relative navigation results depend on high-precision acceleration sensors. Finally, simulation studies on a chief-deputy formation flying control system are performed to verify the effectiveness and superiority of the proposed relative navigation algorithm.
Social implications
This paper provides a reference in solving the problem of high-precision relative navigation in tight formation-keeping application.
Originality/value
This paper proposes a novel on-line identification method for thrust acceleration and shows that thrust identification-based modified EKF is more efficient in relative navigation for tight formation-keeping.
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Keywords
Jihe Wang and Shinichi Nakasuka
The purpose of this paper is to propose an intuitive and effective cluster flight orbit design method for fractionated spacecraft.
Abstract
Purpose
The purpose of this paper is to propose an intuitive and effective cluster flight orbit design method for fractionated spacecraft.
Design/methodology/approach
Based on the concept of fractionated spacecraft, orbit design requirements for cluster flight in the case of fractionated spacecraft are proposed, and categorized into three requirements: stabilization requirement, passive safety requirement, and the maximum inter‐satellite distance requirement. These design requirements are then reformulated in terms of relative eccentricity and inclination vectors (E/I vectors) using a relative motion model based on relative orbital elements (ROEs). By using ROEs theory, the cluster flight orbit design issue is modelled as the distribution of relative E/I vectors for each member satellite in the cluster, and solved by combining three different heuristic search methods and one nonlinear programming (NLP) method.
Findings
The simulation results show that the NLP method is valid and efficient in solving the cluster flight orbit design problem and that for some cluster flight scenarios, the heuristic search methods can be adopted to give feasible solutions without the NLP method.
Research limitations/implications
The cluster flight scenario in this paper is limited because the cluster should be in the near‐circular low earth orbit (LEO), and the relative distance between the member satellites should be small enough to satisfy the relative motion linearization assumption.
Practical implications
The cluster flight orbit design method proposed in this paper can be applied by fractionated spacecraft mission designers to propose potential cluster flight orbit solutions.
Originality/value
In this paper, the relative E/I vectors method is adopted to propose an intuitive and effective cluster flight orbit design method for fractionated spacecraft.
Details
Keywords
Jihe Wang, Xibin Cao and Jinxiu Zhang
The purpose of this paper is to propose a fuel‐optimal virtual centre selection method for formation flying maintenance in the J2 perturbed environment.
Abstract
Purpose
The purpose of this paper is to propose a fuel‐optimal virtual centre selection method for formation flying maintenance in the J2 perturbed environment.
Design/methodology/approach
Based on the relative orbital elements (ROE) theory, the J2 perturbed relative motions between different satellites in the formation are analyzed, and then the fuel‐optimal virtual centre selection issue for formation flying maintenance are parameterized in terms of ROE. In order to determine the optimal virtual centre, two theories are proposed in terms of ROE.
Findings
Numerical simulations demonstrate that the fuel‐optimal virtual centre selection method is valid, and the control of the ROE of each satellite with respect to a virtual optimal centre of the formation is more efficient regarding the fuel consumption than the control of all satellites with respect to a satellite belonging to the formation.
Research limitations/implications
The fuel‐optimal virtual centre selection method is valid for formation flying mission whose member satellite in circular or near circular orbit.
Practical implications
The fuel‐optimal virtual centre selection approach can be used to solve formation flying maintenance problem which involves multiple satellites in the formation.
Originality/value
The paper proposes a fuel‐optimal virtual centre selection method in terms of ROE, and shows that keeping the formation with respect the optimal virtual centre is more fuel efficient.
Details
Keywords
Haykel Hamdi and Jihed Majdoub
Risk governance has an important influence on the hedging performances in option pricing and portfolio hedging in both discrete and dynamic case for both conventional and Islamic…
Abstract
Purpose
Risk governance has an important influence on the hedging performances in option pricing and portfolio hedging in both discrete and dynamic case for both conventional and Islamic indexes. The paper aims to discuss these issues.
Design/methodology/approach
This paper explores option pricing and portfolio hedging in a discrete and dynamic case with transaction costs. Monte Carlo simulations are applied to both conventional and Islamic indexes in US and UK markets. Simulations show that conventional and Islamic assets do not exhibit the same price and portfolio hedging strategy governance.
Findings
The authors conclude that Islamic assets show different option price and hedging strategy compared to their conventional counterpart.
Originality/value
The research question of this paper aims at filling the gap in the empirical literature by exploring option price and hedging structure for both conventional and Islamic indexes in US and UK stock markets.
Details
Keywords
Bifeng Zhu and Gebing Liu
The research on sustainable campus is related to environmental protection and the realization of global sustainable development goals (SDGs). Because the sustainable campus…
Abstract
Purpose
The research on sustainable campus is related to environmental protection and the realization of global sustainable development goals (SDGs). Because the sustainable campus development in China and Japan is carried out around buildings, this paper takes Kitakyushu Science and Research Park as a case to study the characteristics and typical model of sustainable campus in Japan by combined with the characteristics of Chinese sustainable campus.
Design/methodology/approach
This study compares the evaluation standards of green buildings between China and Japan, then compares the assessment results of the same typical green building case and finally summarizes the development mode and main realization path by discussing the implications of green buildings on campus sustainability.
Findings
The results show that (1) the sustainable campus evaluation in Japan mainly pays attention to the indoor environment, energy utilization and environmental problems. (2) Buildings mainly affect the sustainability of the campus in three aspects: construction, transportation and local. (3) The sustainable campus development model of Science and Research Park can be summarized as follows: taking green building as the core; SDGs as the goals; education as the guarantee; and the integration of industry, education and research as the characteristics.
Practical implications
It mainly provides construction experience for other campuses around the world to coordinate the contradictions between campus buildings and the environment based on sustainable principles in their own construction. It proposes a new sustainable campus construction path of “building–region–environment” integrated development.
Originality/value
This study provides theoretical framework for the development of sustainable campuses that includes long-term construction ideas and current technological support greatly improving the operability of practical applications. It not only enriches the sample cases of global sustainable campuses but also provides new ideas and perspectives for the sustainable development research of the overall campus through quantitative evaluation of building and environmental impacts.