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Adaptive Prescribed Performance Control for Flexible Spacecraft with Input saturation and Actuator Misalignment

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Tsinghua Science and Technology 2019年第6期24卷 694-705页

作者： Jiawei Tao Tao Zhang Yongfang Nie Department of Automation Tsinghua UniversityBeijing 100084China Department of Strategic Missile and Underwater Weapon Naval Submarine AcademyQingdao 266071China

In this paper, a flexible spacecraft attitude control scheme that guarantees vibration suppression and prescribed performance on transient-state behavior is proposed. Here, parametric uncertainty, external disturbance, unmeasured elastic vibration, actuator saturation, and even configuration misalignment are considered. To guarantee prescribed performance bounds on the transient-and steady-state control errors, a performance constrained control law is formulated with an error transformed function. An elastic modal observer is employed to estimate the unmeasured flexible modal variables, and a command filter is adopted to avoid the tedious analytical computations of time derivatives of virtual control inherent in the control design. Subsequently, a novel auxiliary system is developed to compensate the adverse effects of the actuator saturation constraints, and a compensation term is integrated into the control law to tackle the configuration misalignment. A comparative simulation study is carried out to illustrate the effectiveness and advantages of the proposed approach.

关键词： flexible spacecraft modal observer vibration suppression prescribed performance input saturation actuator misalignment

Smart homing guidance strategy with control saturation against a cooperative target-defender team

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Journal of Systems Engineering and Electronics 2019年第2期30卷 366-383页

作者： GUO Hang FU Wenxing FU Bin CHEN Kang YAN Jie School of Astronautics Northwestern Polytechnical University

A smart homing guidance strategy with control saturation against a target-defender team is derived. It is noteworthy that a cooperative strategy of the target-defender team is applied,which has been proved more challenging for the homing guidance.The defender missile is launched by the target and guided by a cooperative augmented proportional navigation(APN). At the same time, the target performs a one-switch maneuver to cooperate and minimize the defender's acceleration requirement. The problem is analyzed for arbitrary-order linear dynamics of the agents in the linearized form but validated by the mathematical simulations by using nonlinear kinematics. The perfect information of three agents' states is assumed. Then, a method to deal with the target-defender team is proposed. It contains a combined performance index penalizing the miss distance relative to the target and energy consumption in the whole duration. Besides, the specific miss distance related to the defender is regarded as an inequality constraint. An analytical solution for the smart guidance strategy against the APN guided defender is derived. Meanwhile, the control saturations are introduced to get more realistic and reasonable insights to this practical target-missile-defender problem. A simple but effective iterative searching technique is proposed to determine the saturation time points. The solution provides an optimal homing strategy to evade the defender with a specific miss distance and intercept the target with the minimum miss distance in the minimum energy manner. Nonlinear two-dimensional simulation results are used to validate the theoretical analysis. By comparison with the optimal differential game guidance(ODGG) and the combined minimum effort guidance(CMEG), the superiority of this smart guidance strategy is concluded.

关键词： smart homing guidance control saturation targetmissile-defender iterative searching technique

Robust adaptive compensation control for unmanned autonomous helicopter with input saturation and actuator faults

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Chinese Journal of Aeronautics 2019年第10期32卷 2299-2310页

作者： Kun YAN Mou CHEN Qingxian WU Ronggang ZHU College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Luoyang Institute of Electro-Optical Equipment of AVIC Luoyang 471000China

This paper studies a robust adaptive compensation Fault Tolerant Control(FTC)for the medium-scale Unmanned Autonomous Helicopter(UAH)in the presence of external disturbances,actuator faults and input saturation.To improve the disturbance rejection capacity of the UAH system in actuator healthy case,an adaptive control method is adopted to cope with the external disturbances and a nominal controller is proposed to stabilize the system.Meanwhile,compensation control inputs are designed to reduce the negative effects derived from actuator faults and input saturation.Based on the backstepping control and inner-outer loop control technologies,a robust adaptive FTC scheme is developed to guarantee the tracking errors convergence.Under the presented FTC controller,the uniform ultimate boundedness of all closed-loop signals is ensured via Lyapunov stability analysis.Simulation results demonstrate the effectiveness of the proposed control algorithm.

关键词： Compensation control Fault tolerant control Input saturation Tracking control Unmanned autonomous helicopter

Kinetics of carbonated decomposition of hydrogarnet with different silica saturation coefficients

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International Journal of Minerals,Metallurgy and Materials 2020年第4期27卷 472-482页

作者： Xiao-feng Zhu Ting-an Zhang Guo-zhi Lü State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China School of Material Science and Engineering Lanzhou University of TechnologyLanzhou 730050China Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education Northeastern UniversityShenyang 110819China Special Metallurgy and Process Engineering Institute School of MetallurgyNortheastern UniversityShenyang 110819China

Carbonated decomposition of hydrogarnet is one of the vital reactions of the calcification–carbonation method,which is designed to dispose of low-grade bauxite and Bayer red mud and is a novel eco-friendly method.In this study,the effect of the silica saturation coefficient(x)on the carbonation of hydrogarnet was investigated from the kinetic perspective.The results indicated that the carbonation of hydrogarnets with different x values(x=0.27,0.36,0.70,and 0.73)underwent two stages with significantly different rates,and the kinetic mechanisms of the two stages can be described by the kinetic functions R3 and D3.The apparent activation energies at Stages 1 and 2 were 41.96–81.64 and 14.80–34.84 kJ/mol,respectively.Moreover,the corresponding limiting steps of the two stages were interfacial chemical reaction and diffusion.

关键词： Bayer red mud hydrogarnet calcification carbonation kinetics silica saturation coefficient

Mechanism of contact angle saturation and an energy-based model for electrowetting

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Chinese Physics B 2016年第6期25卷 360-365页

作者：赵瑞梁忠诚 College of Optoelectronic Engineering Center of Optofluidic TechnologyNanjing University of Posts and Telecommunications

Electrowetting,as a well-known approach to increasing droplet wettability on a solid surface by electrical bias,has broad applications.However,it is limited by contact angle saturation at large voltage.Although several debated hypotheses have been proposed to describe it,the physical origin of contact angle saturation still remains obscure.In this work,the physical factors responsible for the onset of contact angle saturation are explored,and the correlated theoretical models are established to characterize electrowetting behavior.Combination of the proper 3-phase system employed succeeds in dropping the saturating contact angle below 25？,and validates that the contact angle saturation is not a result of devicerelated imperfection.

关键词： electrowetting contact angle saturation

Data-driven model-free adaptive attitude control of partially constrained combined spacecraft with external disturbances and input saturation

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Chinese Journal of Aeronautics 2019年第5期32卷 1281-1293页

作者： Han GAO Guangfu MA Yueyong LYU Yanning GUO Department of Control Science and Control Engineering Harbin Institute of Technology

This study presents an improved data-driven Model-Free Adaptive Control(MFAC)strategy for attitude stabilization of a partially constrained combined spacecraft with external disturbances and input saturation. First, a novel dynamic linearization data model for the partially constrained combined spacecraft with external disturbances is established. The generalized disturbances composed of external disturbances and dynamic linearization errors are then reconstructed by a Discrete Extended State Observer(DESO). With the dynamic linearization data model and reconstructed information, a DESO-MFAC strategy for the combined spacecraft is proposed based only on input and output data. Next, the input saturation is overcome by introducing an antiwindup compensator. Finally, numerical simulations are carried out to demonstrate the effectiveness and feasibility of the proposed controller when the dynamic properties of the partially constrained combined spacecraft are completely unknown.

关键词： Attitude control Combined spacecraft Data-driven control Discrete Extended State Observer(DESO) Input saturation

Stability analysis of uncertain fractional-order neutral-type delay systems with actuator saturation

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Frontiers of Information Technology & Electronic Engineering 2021年第10期22卷 1402-1412页

作者： Zahra Sadat AGHAYAN Alireza ALFI J.A.TENREIRO MACHADO Faculty of Electrical and Robotic Engineering Shahrood University of TechnologyShahrood 36199-95161Iran Institute of Engineering Polytechnic of PortoRua Dr.Ant´onio Bernardino de Almeida 431Porto 4249-015Portugal

This study analyzes the problem of robust stability of fractional-order delay systems of neutral type under actuator saturation.A Lyapunov–Krasovskii(LK)function is constructed and conditions of the asymptotic robust stability of such systems are given,which are formulated by linear matrix inequalities(LMIs),using the Lyapunov direct method.An algorithm is introduced to compute the gain of the state feedback controller for extending the domain of attraction.The theoretical results are validated using some numerical examples.

关键词： Fractional-order system Stability Neutral delay Robust saturation

LPV modeling and controller design for body freedom flutter suppression subject to actuator saturation

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Chinese Journal of Aeronautics 2020年第10期33卷 2679-2693页

作者： Wei TANG Yu WANG Jiawei GU Zhiwei SUN School of Automation Northwestern Polytechnical UniversityXi’an 710129China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China Research Institute of Unmanned Aerial Vehicle Northwestern Polytechnical UniversityXi’an 710072China

In recent years,the Active Flutter Suppression(AFS)employing Linear ParameterVarying(LPV)framework has become a hot spot in the research field.Nevertheless,the flutter suppression technique is facing two severe challenges.On the one hand,due to the fatal risk of flight test near critical airspeed,it is hard to obtain the accurate mathematical model of the aeroelastic system from the testing data.On the other hand,saturation of the actuator may degrade the closed-loop performance,which was often neglected in the past work.To tackle these two problems,a new active controller design procedure is proposed to suppress flutter in this paper.Firstly,with the aid of LPV model order reduction method and State-space Model Interpolation of Local Estimates(SMILE)technique,a set of high-fidelity Linear Time-Invariant(LTI)models which are usually derived from flight tests at different subcritical airspeeds are reduced and interpolated to construct an LPV model of an aeroelastic system.And then,the unstable aeroelastic dynamics beyond critical airspeed are‘predicted’by extrapolating the resulting LPV model.Secondly,based on the control-oriented LPV model,an AFS controller in LPV framework which is composed of a nominal LPV controller and an LPV anti-windup compensator is designed to suppress the aeroelastic vibration and overcome the performance degradation caused by actuator saturation.Although the nominal LPV controller may have superior performance in linear simulation in which the saturation effect is ignored,the results of the numerical simulations show that the nominal LPV controller fails to suppress the Body Freedom Flutter(BFF)when encountering the actuator saturation.However,the LPV anti-windup compensator not only enhances the nominal controller’s performance but also helps the nominal controller to stabilize the unstable aeroelastic system whenencountering serious actuator saturation.

关键词： Anti-windup compensation Flutter suppression Linear parameter-varying interpolation Model order reduction saturation

Adaptive nonsingular fast terminal sliding mode control for underwater manipulator robotics with asymmetric saturation actuators

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Control Theory and Technology 2020年第1期18卷 81-91页

作者： Zeng cheng ZHOU Guoyuan TANG Hui HUANG Lijun HAN Ruikun XU School of Naval Architecture and Ocean Engineering Huazhong University of Science and TechnologyWuhan Hubei 430074China Collaborative Innovation Center for Advanced Ship and Deep-sea Exploration(CISSE) Wuhan Hubei 430074China

In this paper,an adaptive nonsingular fast terminal sliding mode control(ANFTSMC)is proposed for underwater manipulator robotics with asymmetric actuator saturations and unknown time-varying(TV)external disturbances.Firstly,the nonsingular fast terminal sliding mode(NFTSM)control scheme is conducted for the underwater manipulator robotics,which guarantees the boundedness of all the signals in the control system.Secondly,the adaptive method and the smooth hyperbolic tangent(tanh)function are introduced to address the unknown TV external disturbances and the input saturation errors.Thus the prior knowledge about the upper bounds of the system uncertainties is not needed in this paper.To deal with the nonlinear asymmetric input saturation issue,a Gaussian error function is employed in the asymmetric saturation module so that the discontinuous input signals can be transformed into smooth forms.Thirdly,the rigorous mathematical verification is conducted to demonstrate the stability and finite-time convergence of the closed-loop control system via the Lyapunov theory.Finally,numerical simulations are performed on a two-link underwater manipulator robotic system to illustrate the effectiveness of the proposed controller.

关键词： Finite time stability sliding mode control asymmetric saturation underwater manipulator Gaussian error function