Shanghai Key Laboratory of Space Intelligent Control Technology

Shanghai, China

Shanghai Key Laboratory of Space Intelligent Control Technology

Shanghai, China
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Tan T.-L.,Shanghai Institute of Technology | Tan T.-L.,Shanghai Key Laboratory of Space Intelligent Control Technology | Wu H.-L.,Shanghai Institute of Technology | Wu H.-L.,Shanghai Key Laboratory of Space Intelligent Control Technology
Yuhang Xuebao/Journal of Astronautics | Year: 2016

According to the requirements of space applications such as spacecraft RVD, formation flight and on-orbit operation, the relative motion between spacecraft is analyzed and modeled. Under the assumption of the constant thrust action, the relative motion is solved analytically. The expected deviation of the relative position and relative velocity of the spacecraft is obtained by using the model prediction method. A full state feedback controller about minimum norm and least square of the expected deviation is constructed based on the generalized inverse transformation. A guidance law generally applicable to nearly circular orbit and elliptical orbit is proposed, which can realize orbital rendezvous, hovering and fly-around with high precision and high stability by the synchronous control of the relative position and velocity. The simulation results verify the feasibility and effectiveness of the proposed method. © 2016, Editorial Dept. of JA. All right reserved.


Tan T.-L.,Shanghai Institute of Technology | Tan T.-L.,Shanghai Key Laboratory of Space Intelligent Control Technology
Yuhang Xuebao/Journal of Astronautics | Year: 2016

According to the requirement of space applications such as spacecraft RVD, formation flight and in-orbit operation in high elliptical orbits, the relative motion between the spacecraft in high elliptical orbit is analyzed and modeled. Using the method of power series, the approximate solutions of the system are solved in two cases, i.e. under the impulse thrust control and under the constant thrust control. By the transformation of the system solutions and the reconstruction of the system states, three guidance laws for rendezvous are given. The pulse guidance law under the assumption of impulse thrust control is similar to Hill's Guidance for near-circular orbit. However, the full state feedback guidance law under the assumption of constant thrust force control realizes the control of both relative position and relative velocity in the process of rendezvous guidance, hovering and tracking fly-around control. By constructing the new system states, the variable coefficient full state feedback guidance law improves the guidance accuracy of the relative velocity and reduces the maximal orbit control acceleration needed in the relative guidance process. The guidance effect of these three guidance laws is verified and compared by means of mathematical simulation. The methods proposed in this paper solve the relative rendezvous guidance, hovering and tracking fly-around control problem in the elliptical orbits. © 2016, Editorial Dept. of JA. All right reserved.


Zhang S.,Harbin Institute of Technology | Zhao Y.,Harbin Institute of Technology | Chen M.,Harbin Institute of Technology | Cao X.,Harbin Institute of Technology | He L.,Shanghai Key Laboratory of Space Intelligent Control Technology
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2011

The reaction wheels play an important role in shaping satellite attitude command. To ensure the reliability of satellite in orbit, the reaction wheels are often overactuated with more than three reaction wheels. Therefore, dynamic control allocation method based on pseudo-inverse method distributing the desired control command among the reaction wheels is proposed. But for controls constrained to operational limits, the pseudo-inverse approach yields admissible control deflections for only a small portion of the set of attainable moments. So a null-space method is used to modify the results. Under the assumption that the attitude changes smoothly when satellite is stabilized, the minimum-torque dynamic control allocation can remove the unexpected signals and reduce noise effect in attitude control by limiting the differences between current value and one-step previous value. In this way, the precision of attitude control system is improved. Finally, the proposed dynamic control allocation method is tested in removing undesired signals and reducing noise effects. The method is proved to be feasible and effective after simulation.


Yuan C.-X.,Harbin Institute of Technology | Zhou Z.-X.,Harbin Institute of Technology | Yue F.,Shanghai Key Laboratory of Space Intelligent Control Technology
Proceedings - 2012 5th International Conference on Intelligent Computation Technology and Automation, ICICTA 2012 | Year: 2012

The properties of Terahertz (THz) waves propagation in a bounded plasma slab with high plasma density and high collision frequency are studied in this paper. The method of impedance transformation in multiple dielectrics is used to describe the propagation of THz waves in the plasma layer. The effect of various plasma parameters such as the plasma density, sheet thickness, incident wave frequency and collision frequency on the power transmission, absorption and reflection is investigated. The calculated numerical results show that a THz wave can transmit though a dense and high collision frequency (to the order of 10 12-THz) plasma with reflectionless and absorptionless power. When the change of plasma density leads the plasma frequency to be in the vicinity of the incident THz wave frequency, the plasma can absorb the most THz wave power. The potential applications of these propagation properties are discussed in this paper. © 2012 IEEE.


Wang Y.,Harbin Institute of Technology | Yuan C.,Harbin Institute of Technology | Zhou Z.,Harbin Institute of Technology | Gao R.,Harbin Institute of Technology | And 2 more authors.
Physics of Plasmas | Year: 2012

The propagation characteristics of a Gaussian laser beam in cold plasma with the electron collision frequency modulated by laser intensity are presented. The nonlinear dynamics of the ponderomotive force, which induce nonlinear self-focusing as opposed to spatial diffraction, are considered. The effective dielectric function of the Drude model and complex eikonal function are adopted in deriving coupled differential equations of the varying laser beam parameters. In the framework of ponderomotive nonlinearity, the frequency of electron collision in plasmas, which is proportional to the spatial electron density, is strongly interrelated with the laser beam propagation characteristics. Hence, the propagation properties of the laser beam and the modulated electron collision frequency distribution in plasma were studied and explained in depth. Employing this self-consistent method, the obtained simulation results approach practical conditions, which is of significance to the study of laser-plasma interactions. © 2012 American Institute of Physics.


Wang Y.,Harbin Institute of Technology | Yuan C.,Harbin Institute of Technology | Zhou Z.,Harbin Institute of Technology | Li L.,Shanghai Key Laboratory of Space Intelligent Control Technology | Du Y.,Shanghai Key Laboratory of Space Intelligent Control Technology
Physics of Plasmas | Year: 2011

The propagation characters of Gaussian laser beam in plasmas of Drude model have been investigated by complex eikonal function assumption. The dielectric constant of Drude model is representative and applicable in describing the cold unmagnetized plasmas. The dynamics of ponderomotive nonlinearity, spatial diffraction, and collision attenuation is considered. The derived coupling equations determine the variations of laser beam and irradiation attenuation. The modified laser beam-width parameter F, the dimensionless axis irradiation intensity I, and the spatial electron density distribution n/n0 have been studied in connection with collision frequency, initial laser intensity and beam-width, and electron temperature of plasma. The variations of laser beam and plasma density due to different selections of parameters are reasonably explained, and results indicate the feasible modification of the propagating characters of laser beam in plasmas, which possesses significance to fast ignition, extended propagation, and other applications. © 2011 American Institute of Physics.


Yuan C.-X.,Harbin Institute of Technology | Zhou Z.-X.,Harbin Institute of Technology | Zhang J.W.,Harbin Institute of Technology | Xiang X.-L.,Shanghai Key Laboratory of Space Intelligent Control Technology | And 2 more authors.
IEEE Transactions on Plasma Science | Year: 2011

A multilayer radar-absorbing structure with plasma- and radar-absorbing material (RAM) is established to investigate the stealth mechanisms of the multilayer absorber. The method of impedance transformation with multiple dielectrics is used to analyze the propagation of electromagnetic (EM) waves in the multilayer structure. The dependences of EM waves attenuation on the parameters of the plasma and RAMs are provided. The numerical results indicate that generally speaking, the joint attention effect of RAM and plasma is better than the effect of either RAM or plasma solely. The attenuation of an EM wave in the structure is strongly affected by: a) the characteristics of RAMs; b) the width of the plasma layer; c) the parameters of the outer layer material; d) the electron density of the plasma; and e) the collision frequency between electrons and neutrals. It is demonstrated that detailed numerical analyses are useful in practical applications pertaining to the control of the reflection of EM waves through a multilayer radar-absorbing structure with plasma and RAMs. © 2011 IEEE.


Huang H.,Nanjing University of Aeronautics and Astronautics | Pan M.,Nanjing University of Aeronautics and Astronautics | Lu Z.,Nanjing University of Aeronautics and Astronautics | Lu Z.,Shanghai Key Laboratory of Space Intelligent Control Technology
Chinese Journal of Aeronautics | Year: 2015

Hardware-in-the-loop (HWIL) simulation technology can verify and evaluate the radar by simulating the radio frequency environment in an anechoic chamber. The HWIL simulation technology of wide-band radar targets can accurately generate wide-band radar target echo which stands for the radar target scattering characteristics and pulse modulation of radar transmitting signal. This paper analyzes the wide-band radar target scattering properties first. Since the responses of target are composed of many separate scattering centers, the target scattering characteristic is restructured by scattering centers model. Based on the scattering centers model of wide-band radar target, the wide-band radar target echo modeling and the simulation method are discussed. The wide-band radar target echo is reconstructed in real-time by convoluting the transmitting signal to the target scattering parameters. Using the digital radio frequency memory (DRFM) system, the HWIL simulation of wide-band radar target echo with high accuracy can be actualized. A typical wide-band radar target simulation is taken to demonstrate the preferable simulation effect of the reconstruction method of wide-band radar target echo. Finally, the radar target time-domain echo and high-resolution range profile (HRRP) are given. The results show that the HWIL simulation gives a high-resolution range distribution of wide-band radar target scattering centers. © 2015 The Authors.


Yuan C.-X.,Harbin Institute of Technology | Zhou Z.-X.,Harbin Institute of Technology | Zhang J.W.,Harbin Institute of Technology | Xiang X.-L.,Shanghai Key Laboratory of Space Intelligent Control Technology | And 2 more authors.
IEEE Transactions on Plasma Science | Year: 2011

Terahertz (THz) waves have been attracting much attention for a variety of technologies in recent years. However, only limited several experimental investigations on the terahertz characterization of plasmas have been reported. In this paper, a finite-difference time-domain method is applied to model the terahertz wave propagation in a high-temperature unmagnetized plasma. The rational polynomial function is established based on a hot plasma dispersion relation, and then, the relationship between andis deduced in the time domain. In the frequency domain, the reflection and transmission coefficients of terahertz waves through the hot unmagnetized plasma slab are computed, and their dependences on plasma frequency, plasma thickness, and collision frequency are studied. The results show theoretically that, when the terahertz wave passes through the plasma layer, its amplitude is obviously modulated by the electron density profile, the collision frequency, and the electron temperature. Finally, the potential application of terahertz waves in plasma diagnostics has been discussed. © 2011 IEEE.


Cheng Y.,Nanjing University of Aeronautics and Astronautics | Jiang B.,Nanjing University of Aeronautics and Astronautics | Sun J.,Shanghai Aerospace Control Engineering Institute | Sun J.,Shanghai Key Laboratory of Space Intelligent Control Technology | And 2 more authors.
ICIC Express Letters | Year: 2011

This paper is concerned with the design of a robust actuator fault diagnosis and tolerant control scheme for satellite attitude control systems. A bank of sliding mode observers (SMOs) are firstly investigated to detect and isolate single actuator fault for satellite attitude control systems with input disturbance. When an actuator undergoes unknown fault, it is disabled. Under such condition, a novel fault tolerant controller based on sliding mode control method is proposed to keep system safe using the remaining actuators. Simulation results demonstrate the effectiveness of the proposed method for satellite attitude control systems. © 2011 ISSN 1881-803X.

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