Design and comparison of LQG/LTR and H∞ controllers for a VSTOL flight control system

Zarei, Jafar; Montazeri, Allahyar; Motlagh, Mohammad Reza Jahed; Poshtan, Javad

doi:10.1016/j.jfranklin.2006.02.033

Cited by 31 publications

(15 citation statements)

References 9 publications

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“…In LTR theory, there might be two options of recovering the input side (Kalman filter) or output side (LQR controller) of the system given by (14). However, the two step separation approach is popular among contemporary research community [19]- [20].…”

Section: Ltr Technique To Increase Stability Marginsmentioning

confidence: 99%

Missile attitude control via a hybrid LQG-LTR-LQI control scheme with optimum weight selection

Das

Halder

2014

2014 First International Conference on Automation, Control, Energy and Systems (ACES)

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Abstract-This paper proposes a new strategy for missile attitude control using a hybridization of Linear Quadratic Gaussian (LQG), Loop Transfer Recovery (LTR), and Linear Quadratic Integral (LQI) control techniques. The LQG control design is carried out in two steps i.e. firstly applying Kalman filter for state estimation in noisy environment and then using the estimated states for an optimal state feedback control via Linear Quadratic Regulator (LQR). As further steps of performance improvement of the missile attitude control system, the LTR and LQI schemes are applied to increase the stability margins and guarantee set-point tracking performance respectively, while also preserving the optimality of the LQG. The weighting matrix (Q) and weighting factor (R) of LQG and the LTR fictitious noise coefficient (q) are tuned using Nelder-Mead Simplex optimization technique to make the closed-loop system act faster. Simulations are given to illustrate the validity of the proposed technique.

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Section: Ltr Technique To Increase Stability Marginsmentioning

confidence: 99%

Missile attitude control via a hybrid LQG-LTR-LQI control scheme with optimum weight selection

Das

Halder

2014

2014 First International Conference on Automation, Control, Energy and Systems (ACES)

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“…The criteria of stability, robustness and performance are the objectives to be reconciled for any method of effective control. Among the most answered techniques of robust control, [1], [2] outline the solution to a range of optimal control problems. Further algorithms such as loop transfer recovery LTR were developed by [3] to improve the robustness of the more practical LQG when compared to the more robust but less practical LQR.…”

Section: Introductionmentioning

confidence: 99%

“…Since the appearance of the paper by [3] with loop transfer recovery (LTR), many papers have been written on this topic. The most notable ones for continuous time systems are [1], [4], [5] to achieve H 2 and H ∞ norm specifications [1], [6]. In this paper, synthesizing a control l a w by Linear-Quadratic-Gaussian method with loop-Transfert -Recovery (LQG \LTR) which maintains system response and error signals to within specified tolerances so that they are enable to ensure the robustness and performances for the modes of nominal and disturbed operation.…”

Section: Introductionmentioning

confidence: 99%

“…We deduce from the equation of state (17), the transfer matrix of the controller : is the process noise distribution matrix and ρ is a scaled value; then in calculation, the command by return of state (command LQ) starting from an adjustment of the matrices of weighting Q and R so that the matrix of transfer of the open loop of the unit approaches gradually that obtained by the KALMAN filter. A first stage of synthesis LQG/LTR relates to the choice of weighting matrices Q and R for the calculation of the command with return of state LQ in the following way [1], [4] :…”

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confidence: 99%

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Design of a Robust Controller by LQG/LTR Formalism for Francis hydro Turbine Driving a Synchronous Generator

Aurelien*,

Léandre,

Hervé

2019

IJEAT

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This paper presents the design and application of a robust controller by Linear-Quadratic-Gaussian method with Loop-Transfer-Recovery (LQG \LTR) at the same time to carefully attain performance and robustness objectives. To improve Stability, the robust controller has been shown to provide good performance i n normal operations conditions. Objectives cannot be suitable unless the controller can perpetuate such quality in the presence of plant uncertainties or any working conditions in the hydroelectric power plants. The approach is based to synthesizing a robust controller minimizing a quadratic criterion (controller LQG) while using the Loop Transfer Recovery (LTR), to restore robustness properties of the Estimator. In this study, we applied this robust control law on the model of a Francis hydro turbine. Computer simulations are carried out to establish a n d compare the performance and robustness of using the Infinite horizon control ( H ), internal model control (IMC), Proportional Integral Derived (PID) and LQG/LTR controllers.

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“…Therefore, it is imperative to investigate finite-time robust flight controllers for unmanned helicopters in the presence of disturbances. [3][4][5][6] In the past decades, many elegant control methods have been employed for the unmanned helicopters, such as linear quadratic gaussian, 7 H ∞ , 8 feedback-linearization control, 9 backstepping, 10 sliding-mode control (SMC). 11 Above all, the SMC method has drawn much attention for its superior disturbance rejection ability.…”

Section: Introductionmentioning

confidence: 99%

High‐order mismatched disturbance rejection control for small‐scale unmanned helicopter via continuous nonsingular terminal sliding‐mode approach

Fang

Liu

2018

Intl J Robust & Nonlinear

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In this paper, the problem of finite-time control for small-scale unmanned helicopter system with high-order mismatched disturbance is investigated via continuous nonsingular terminal sliding-mode control approach. The key idea is to design a novel nonlinear dynamic sliding-mode surface based on finite-time disturbance observer. Then, the finite-time convergence and chattering attenuation capability is guaranteed by the continuous nonsingular terminal sliding-mode control law. Additionally, rigorous finite-time stability analysis for the closed-loop helicopter system is given by means of the Lyapunov theory. Finally, some simulation results demonstrate the effectiveness and predominant properties of the proposed control method for the small-scale unmanned helicopter even in the presence of high-order mismatched disturbance. KEYWORDS continuous nonsingular terminal sliding mode control (CNTSMC), finite-time disturbance observer (FTDO), high-order mismatched disturbance, unmanned helicopter Int J Robust Nonlinear Control. 2019;29:935-948.wileyonlinelibrary.com/journal/rnc

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Design and comparison of LQG/LTR and H∞ controllers for a VSTOL flight control system

Cited by 31 publications

References 9 publications

Missile attitude control via a hybrid LQG-LTR-LQI control scheme with optimum weight selection

Missile attitude control via a hybrid LQG-LTR-LQI control scheme with optimum weight selection

Design of a Robust Controller by LQG/LTR Formalism for Francis hydro Turbine Driving a Synchronous Generator

High‐order mismatched disturbance rejection control for small‐scale unmanned helicopter via continuous nonsingular terminal sliding‐mode approach

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