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Roll angular rate extraction based on modified spline-kernelled chirplet transform

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Defence Technology（防务技术） 2022年第5期18卷 876-890页

作者： Hui Zhao Zhong Su Qing Li Fu-chao Liu Ning Liu School of Automation Beijing Institute of TechnologyBeijing100081China Beijing key laboratory of High dynamic Navigation Technology Beijing Information Science and Technology UniversityBeijing100192China

The roll angular rate is much crucial for the guidance and control of the *** the high-speed rotation of the projectile brings severe challenges to the direct measurement of the roll angular ***,the radial magnetometer signal is modulated by the high-speed rotation,thus the roll angular rate can be achieved by extracting the instantaneous frequency of the radial magnetometer *** objective of this study is to find out a precise instantaneous frequency extraction method to obtain an accurate roll angular *** reach this goal,a modified spline-kernelled chirplet transform(MSCT)algorithm is proposed in this *** to the nonlinear frequency modulation characteristics of the radial magnetometer signal,the existing time-frequency analysis methods in literature cannot obtain an excellent energy concentration in the time-frequency plane,thereby leading to a terrible instantaneous frequency extraction ***,the MSCT can overcome the problem of bad energy concentration by replacing the short-time Fourier transform operator with the Chirp Z-transform operator based on the original spline-kernelled chirplet *** introduction of Chirp Z-transform can improve the construction accuracy of the transform *** the construction accuracy of the transform kernel determines the concentration of time-frequency distribution,the MSCT can obtain a more precise instantaneous *** performance of the MSCT was evaluated by a series of numerical simulations,high-speed turntable experiments,and real flight *** evaluation results show that the MSCT has an excellent ability to process the nonlinear frequency modulation signal,and can accurately extract the roll angular rate for the high spinning projectiles.

关键词： High spinning projectile Roll angular rate Time-frequency analysis Spline-kernelled chirplet transform Chirp Z-transform

Observation of specific ion effects in humus aggregation process

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Pedosphere 2021年第5期31卷 736-745页

作者： Rui TIAN Xinmin LIU Xiaodan GAO Rui LI Hang LI Chongqing key laboratory of Soil Multi-scale Interfacial process College of Resources and EnvironmentSouthwest UniversityChongqing 400715(China)

Specific ion effects play a vital role in a variety of colloidal and interfacial ***,few studies have reported the specific ion effects in the humus aggregation process,which strongly influence the transport and fate of environmental *** this study,soil humus colloids were prepared and characterized,and the specific ion effects on humus aggregation in electrolyte solutions were investigated at a variety of concentrations and pH values using dynamic light scattering *** energy(ΔE),which is known to reflect the dynamics and stability of a colloidal system,was used to quantitatively characterize the specific ion *** results showed that given ΔE value of 2.48×10^(3) J mol^(-1) at pH 3.0,the electrolyte concentrations were 91.6,58.2,3.8,and 0.8 mmol L^(-1) for Na^(+),K^(+),Mg^(2+),and Ca_(2+),respectively,thus indicating significant specific ion effects in the humus aggregation *** importantly,decreasing the electrolyte concentrations increased the differences in the ΔE value between two cation species with the same valence(i.e.,ΔE_(Na)-ΔE_(K) and ΔE_(Mg)-ΔE_(Ca)),while increasing the pH increased the magnitude of ΔE_(Mg)-ΔE_(Ca).However,the classic Derjaguin,Landau,Verwey,and Overbeek(DLVO)theory and the double layer theory,as well as the currently widely used ionic hydration and dispersion effects,failed to predict the experimentally observed increase in the specific ion effects with decreasing electrolyte concentrations in a quantitative *** results have implications for the necessity of involving specific ion effects for a better understanding of humus aggregation and interactions in aqueous and soil systems.

关键词： Derjaguin Landau Verwey and Overbeek theory double layer theory ionic dispersion ionic hydration supramolecular aggregates

Nonlinear asymptotic attitude tracking control of an underactuated 3-degree-of-freedom helicopter using neural network feedforward term

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控制理论与应用（英文版） 2013年第3期11卷 428-435页

作者： Xiang LIU Bin XIAN Jianchuan GUO Bo ZHAO Chen DIAO Institute of Robotics and Autonomous System Tianjin Key Laboratory of Process Measurement and Control and School of Electrical Engineering and Automation Tianjin University

This paper proposes a new asymptotic attitude tracking controller for an underactuated 3-degree-of-freedom （DOF） laboratory helicopter system by using a nonlinear robust feedback and a neural network （NN） feedforward term. The nonlinear robust control law is developed through a modified inner-outer loop approach. The application of the NN-based feedforward is to compensate for the system uncertainties. The proposed control design strategy requires very limited knowledge of the system dynamic model, and achieves good robustness with respect to system parametric uncertainties. A Lyapunov-based stability analysis shows that the proposed algorithms can ensure asymptotic tracking of the helicopter＇s elevation and travel motion, while keeping the stability of the closed-loop system. Real-time experiment results demonstrate that the controller has achieved good tracking performance.

关键词： 3-DOF helicopter Nonlinear Robust control Asymptotic tracking

Improved High Order Model-Free Adaptive Iterative Learning Control with Disturbance Compensation and Enhanced Convergence

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Computer Modeling in Engineering & Sciences 2023年第1期134卷 343-355页

作者： Zhiguo Wang Fangqing Gao Fei Liu key laboratory of Advanced process Control for Light Industry(Ministry of Education) Institute of AutomationJiangnan UniversityWuxi214122China

In this paper,an improved high-order model-free adaptive iterative control(IHOMFAILC)method for a class of nonlinear discrete-time systems is proposed based on the compact format dynamic linearization *** method adds the differential of tracking error in the criteria function to compensate for the effect of the random ***,a high-order estimation algorithmis used to estimate the value of pseudo partial derivative(PPD),that is,the current value of PPD is updated by that of previous *** the rapid convergence of the maximumtracking error is not limited by the initial value of *** convergence of the maximumtracking error is deduced in *** method can track the desired output with enhanced convergence and improved tracking *** examples are used to verify the convergence and effectiveness of the proposed method.

关键词： Pseudo partial derivative enhanced convergence tracking error disturbance compensation

Robust tracking control design for a flexible air-breathing hypersonic vehicle

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Journal of Central South University 2014年第1期21卷 130-139页

作者：张垚鲜斌刁琛赵勃郭建川 Institute of Robotics and Autonomous System Tianjin Key Laboratory of Process Measurement and ControlSchool of Electrical Engineering and AutomationTianjin University

A nonlinear robust controller was presented to improve the tracking control performance of a flexible air-breathing hypersonic vehicle(AHV) which is subjected to system parametric uncertainties and unknown additive time-varying *** longitudinal dynamic model for the flexible AHV was used for the control ***-gain observers were designed to compensate for the system uncertainties and additive *** gain theorem and Lyapunov based stability analysis were utilized to prove the stability of the closed loop *** uniformly ultimately bounded tracking of the vehicle's velocity,altitude and attack angle were achieved under aeroelastic effects,system parametric uncertainties and unknown additive ***/Simulink simulation results were provided to validate the robustness of the proposed control *** simulation results demonstrate that the tracking errors stay in a small region around zero.

关键词： hypersonic vehicles nonlinear robust control flexible mode small gain theorem Lyapunov

Predictive control of a class of bilinear systems based on global off-line models

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第12期7卷 1984-1988页

作者： ZHANG Ri-dong WANG Shu-qing Institute of Advanced process Control National Key Laboratory of Industrial Control Technology Zbejiang University Hangzhou 310027 China

A new multi-step adaptive predictive control algorithm for a class of bilinear systems is presented. The structure of the bilinear system is converted into a simple linear model by using nonlinear support vector machine (SVM) dynamic approximation with analytical control law derived. The method does not need on-line parameters estimation because the system’s internal model has been transformed into an off-line global model. Compared with other traditional methods, this control law reduces on-line parameter estimating burden. In addition, its overall linear behavior treating method allows an analytical control law available and avoids on-line nonlinear optimization. Simulation results are presented in the article to illustrate the efficiency of the method.

关键词： Bilinear systems Model predictive control (MPC) Adaptive control Support vector machine (SVM)

Output feedback control of hypersonic vehicles based on neural network and high gain observer

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Science China(Information Sciences) 2011年第3期54卷 429-447页

作者： LI XinDong,XIAN Bin,DIAO Chen,YU YanPing,YANG KaiYan & ZHANG Yao The Tianjin key laboratory of process Measurement and Control,School of Electrical Engineering and Automation,Tianjin University,Tianjin 300072,China The Tianjin key laboratory of process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China

In this paper,the output feedback control problem for a genetic hypersonic vehicle is considered under the restriction that only the vehicle’s velocity and altitude are measurable. High gain observers (HGO) are utilized to provide estimation signals for unmeasurable derivatives of the vehicle’s velocity and altitude. Neural network based feedforward function is designed to compensate for model uncertainties. The proposed control design require less knowledge of the hypersonic vehicle’s dynamic model. A comprehensive stability analysis of the closed loop system under the output feedback control is carried to prove that the proposed control law yields semiglobal uniformly ultimately bounded tracking while keeping all the closed loop signals bounded. Numerical simulation results are presented to validate the proposed control design.

关键词： hypersonic vehicle nonlinear output feedback control neural network high gain observer

Data-driven cooperative output regulation of multi-agent systems under distributed denial of service attacks

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Science China(Information Sciences) 2023年第9期66卷 5-20页

作者： Weinan GAO Zhong-Ping JIANG State key laboratory of Synthetical Automation for process Industries Northeastern University Department of Electrical and Computer Engineering Tandon School of Engineering New York University

This paper addresses an optimal, cooperative output regulation problem for multi-agent systems with distributed denial of service attacks and unknown system dynamics. Unlike existing studies, the proposed solution is essentially a learning-based control strategy such that one can obtain a distributed control policy with internal models through online data and analyze the resilience of closed-loop systems, both without the precise knowledge of system dynamics in the state-space model. The efficiency of the proposed methodology is validated using computer simulations.

关键词： cooperative output regulation adaptive dynamic programming learning-based control multi-agent systems cybersecurity

Bayesian estimation for nonlinear stochastic hybrid systems with state dependent transitions

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Journal of Systems Engineering and Electronics 2012年第2期23卷 242-249页

作者： Shunyi Zhao Fei Liu key laboratory of Advanced process Control for Light Industry(Ministry of Education) Institute of AutomationJiangnan UniversityWuxi 214122P.R.China

The Bayesian approach is considered as the most general formulation of the state estimation for dynamic systems. However, most of the existing Bayesian estimators of stochastic hybrid systems only focus on the Markov jump system, few liter- ature is related to the estimation problem of nonlinear stochastic hybrid systems with state dependent transitions. According to this problem, a new methodology which relaxes quite a restrictive as- sumption that the mode transition process must satisfy Markov properties is proposed. In this method, a general approach is presented to model the state dependent transitions, the state and output spaces are discreted into cell space which handles the nonlinearities and computationally intensive problem offline. Then maximum a posterior estimation is obtained by using the Bayesian theory. The efficacy of the estimator is illustrated by a simulated example .

关键词： Bayesian estimation nonlinear stochastic hybrid sys- tem state dependent transition cell space.