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Systems and control in Aerospace and Astronautics, 2006. ISSCAA 2006. 1st International Symposium on

作者： Baolin Wu Xibin Cao Fuchun Liu Research Center of Satellite Technology Harbin Institute of Technology Harbin China Department of Control Science and Engineering Harbin Institute of Technology Harbin China

ISBN: (纸本)0780393953

Numerous controllers have been proposed based on linear Hill's equations for satellite formation control. To date, most of these controllers assumed that the system model is well defined, and the disturbances are small. Previous studies have failed to consider the problem of disturbance rejection. In this paper, H/sub /spl infin// controllers are designed for disturbance attenuation based on linear Hill's equations. The goal is to design a state-feedback control law which minimizes the H/sub /spl infin// norm of transfer function from disturbance to the regulated outputs, which guarantee stable for the closed-loop system. The problem is reduced to a convex optimization involving linear matrix inequalities (LMIs). The proposed robust controllers are evaluated in simulation. The simulation results demonstrate that the proposed controllers are capable of controlling the satellite formation system more precisely than LQR under various perturbations.

关键词： H/sup /spl infin// control aerospace control artificial satellites closed loop systems convex programming linear matrix inequalities robust control state feedback transfer functions H/sub /spl infin// controllers H/sub /spl infin// synthesis closed-loop

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Relative Attitude control in Satellite Formation Flying with Information Delay

Relative Attitude Control in Satellite Formation Flying with...

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World Congress on Intelligent control and Automation (WCICA)

作者： Huayi Li Yingchun Zhang Wenyi Qiang Baohua Li Research Center of Satellite Harbin Institute of Technology Harbin China Department of Control Science and Engineering Harbin Institute of Technology Harbin China

In leader-follower formation flying, using the leader's rate of rotation, the follower calculates the target attitude and rate of rotation, which are necessary to relative attitude control. In the process of information collecting, computing and transmitting, time delay exists that causes information delay. To deal with it, rate and attitude estimators are presented which provide target rate and attitude real time. Then a PID control law for small satellite with reaction wheels is developed based on them. Simulation results show the approach is valid

关键词： Satellites Delay effects Three-term control Delay estimation Attitude control Wheels Computational modeling NASA Global Positioning System Intelligent control

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Chaos Algorithm of Multilayer Feedforward Neural Network

Chaos Algorithm of Multilayer Feedforward Neural Network

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Chinese control Conference (CCC)

作者： Jia-hai Zhang Yao-qun Xu College of Electrical and Automatic Engineering Sanjiang University Nanjing China Center for Control Theory and Guidance Technology Harbin Institute of Technology Harbin China

By the use of the properties of ergodicity, a chaos algorithm for multilayer feedforward neural network is proposed with combining logistic mapping and BP algorithm. This algorithm can make BP algorithm to skip the lo... 详细信息

关键词： Multi-layer neural network Chaos Neural networks Feedforward neural networks Educational institutions control theory Electronic mail Logistics Convergence TV

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Application of one-degree-of-freedom QFT tracking controller to hydraulic simulator design

Application of one-degree-of-freedom QFT tracking controller...

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Systems and control in Aerospace and Astronautics, 2006. ISSCAA 2006. 1st International Symposium on

作者： Jinying Yu Keding Zhao Jian Cao Liquid Transmission and Control Laboratory Department of Mechanical Engineering Harbin Institute of Technology Harbin China

ISBN: (纸本)0780393953

Phase tracking problem is not especially considered in classical quantitative feedback theory (QFT). A modified one-degree-of-freedom QFT technique which is suitable for both magnitude and phase tracking performance index is proposed to synthesize three-axis hydraulic simulator controller. The proposed method transform uncertain plant tracking performance index into sensitivity constraint and nominal plant tracking error constraint. The former constraint form into QFT sensitivity bounds and the latter one can be founded on Nichols chart directly. Because of omitting pre-filter of classical two-degree-of-freedom QFT control structure, ramp tracking performance index is also enhanced greatly. The modified QFT technique's efficacy is validated by simulation results.

关键词： controllers feedback hydraulic control equipment Nichols chart degree-of-freedom hydraulic simulator controller magnitude tracking nominal plant tracking error constraint phase tracking quantitative feedback theory ramp tracking performance index sensiti

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Noisy image segmentation by modified snake model

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Journal of Physics: Conference Series 2006年第1期48卷 369-372页

作者： Lu, R. Shen, Y. Department of Control Science and Engineering Harbin Institute of Technology Harbin China

A novel segmentation scheme for noisy image is proposed. According to the analysis of wavelet denoising method and multiscale geometric analysis techniques, an improved wavelet denoising algorithm combined with multiscale geometric analysis is presented in this paper first. Due to the isotropic nature of wavelet transform, 2D image details are not well represented in wavelet transform, which results in over smoothing. In this new denoising method, a noisy image is processed by the wavelet denoising method first, and then edges' information which has been wrongly discarded, is picked up from the residue image by multiscale geometric analysis. The final denoising image is a combination of the wavelet denoising result and the edges' information. Furthermore, incorporating prior knowledge on the contours' shape and shape similarity metric based on Fourier descriptors of snakes, a parameter-varying snake model is introduced. It addresses the problem of varying parameters during snake method. Extensive experimental results illustrate the excellent performance. © 2006 IOP Publishing Ltd.

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A Delta-operator Approach to Robust Stabilization for Uncertain Time-delay Systems with Jumping Parameter

A Delta-operator Approach to Robust Stabilization for Uncert...

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World Congress on Intelligent control and Automation (WCICA)

作者： Kai-yu Wu Yan-ming Fu Shuang Li School of Mechanical & Power Engineering Harbin University of Science and Technology Heilongjiang China Center for Control Theory and Guidance Technology Harbin Institute of Technology Heilongjiang China

This paper deals with the robust stabilization for a class of linear Delta-operator formulated uncertain systems with state delays and jumping parameters. The transition of the jumping parameters in systems is governed by a finite-state Markov process. The class of systems is a hybrid class of systems with two components in the vector state. The first component refers to the mode and the second one to the state. The mode is described by a continuous Markov process with finite state space. The state in each mode is denoted by a stochastic differential equation. Based on stability theory in stochastic differential equations, a sufficient condition on the existence of robust stabilizing control law is derived. Based on this condition, a robust memoryless stabilizing control law is designed in terms of a set of linear matrix inequalities. A numerical example demonstrates the effect of the proposed design approach

关键词： Robustness Markov processes Stochastic processes Differential equations Robust stability Robust control Uncertain systems Delay systems Vectors State-space methods

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Optimal Piecewise State Feedback control for Nonlinear Dynamical Systems

Optimal Piecewise State Feedback Control for Nonlinear Dynam...

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World Congress on Intelligent control and Automation (WCICA)

作者： Rui Li Kok Lay Teo Guangren Duan Center for Control Theory and Guidance Technology Harbin Institute of Technology Harbin China Department of Mathematics & Statistics Curtin University of Technology Perth WA Australia

In this paper, we consider a class of optimal piecewise state feedback control problems. For this optimal control problem, the time horizon is divided into N subintervals with the end points of each subinterval being referred to as switching times. The control is given by a piecewise state feedback form, where different feedback gain matrices are allowed for different subintervals. Both the switching instants and the feedback gain matrices on the corresponding subintervals are decision variables to be determined such that a given cost functional is minimized. Our approach is to use a time scaling transform to convert this optimal piecewise state feedback control problem into an equivalent optimal parameter selection problem, where the varying time points are being mapped into fixed time points. Then the gradient formulae of the cost functional are derived. On this basis, the equivalent transformed optimal parameter selection problem can be solved as a nonlinear optimization problem. An illustrative example is solved using the proposed method

关键词： State feedback Optimal control Nonlinear control systems control systems Nonlinear dynamical systems Cost function Matrix converters Automobiles Vehicle driving Differential equations

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Robust H∞ control for Uncertain Descriptor Time-delay Systems with Markov Jumping Parameters

Robust H∞ Control for Uncertain Descriptor Time-delay Syste...

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World Congress on Intelligent control and Automation (WCICA)

作者： Kai-yu Wu Yan-ming Fu Shi-jie Xie School of Mechanical and Power Engineering Harbin University of Science and Technology Heilongjiang China Center for Control Theory and Guidance Technology Harbin Institute of Technology Heilongjiang China

This paper deals with the robust stabilizability and H infin disturbance attenuation for a class of uncertain descriptor time-delay systems with jumping parameters. The transition of the jumping parameters in the systems is governed by a finite-state Markov process. A sufficient condition on robust stabilizability is established based on the stability theory for stochastic differential equations. With the help of a set of coupled linear matrix inequalities, robust H infin controllers are designed to stochastically stabilize the given systems with a prescribed disturbance attenuation level represented by an H infin norm bound constraint. A numerical example demonstrates the effect of the proposed design approach

关键词： Robustness Attenuation Robust stability Markov processes Sufficient conditions Stochastic processes Differential equations Linear matrix inequalities Robust control control systems

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CORRECTING SEMI-MAJOR TO REDUCE EFFECT OF J2 PERTURBATION ON FORMATION FLYING

CORRECTING SEMI-MAJOR TO REDUCE EFFECT OF J2 PERTURBATION ON...

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2006 International Conference on Machine Learning and Cybernetics(IEEE第五届机器学习与控制论坛)

作者： HUA-YI LI BAO-HUA LI YING-CHUN ZHANG WEN-YI QIANG Research Center of Satellite Technology Harbin Institute of Technology Harbin 150001 China Department of Control Science and Engineering Harbin Institute of Technology Harbin 150001China

After the relative motion coordinate frame is defined,linear equations of relative motion described by small orbital element bias are developed with respect to it. And then the differential expressions of relative position drifts due to J2 perturbation are established. Integrating them along the orbit,the drifts without effects of true anomaly are obtained. A cost function denoting the magnitude of drifts is selected. The optimal solution to the function is the optimal correction of semi-major. The calculating formula is available. Numerical simulations are employed to check the fidelity of the *** of illustrations show that the approach has more advantages in reducing the relative position drifts and better shape the relative orbit.

关键词： Formation flying Relative orbit Relative position drift J2 perturbation

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A Fusion Algorithm for Building Maps in Confined Environments for Mobile Robots

A Fusion Algorithm for Building Maps in Confined Environment...

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Computational engineering in Systems Applications, CESA, IMACS Multiconference on FLAGGED

作者： Guoliang Liu Wanjun Hao Shizuo Yan Zengqi Sun Wenyi Qiang Department of Control Science and Engineering Harbin Institute of Technology Harbin China Department of Science and Technology Tsinghua University Beijing China

Some problems associated with building map in confined environments for mobile robots are studied in this work. The uncertainties arising from specular reflection of ultrasonic sensors cannot make mobile robots recognize their surrounding environments correctly when mobile robots navigate in a confined environment. If the environment is known and unchanged, its map can be built with ultrasonic sensors in advance before navigation is performed. This map can provide reliable information about the environment when mobile robots work. A multi-layer fusion algorithm is proposed for building the map in advance. For the situation that the environment is unknown or variable, an adaptive ultrasonic sensor model is applied to build map dynamically. The experiment results indicate that the above fusion algorithms improve the performance of ultrasonic sensors

关键词： Mobile robots Optical reflection Navigation Uncertainty Sensor fusion Robot sensing systems Sensor phenomena and characterization Systems engineering and theory Ash Heuristic algorithms

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