scholarly journals Robust Stability Clearance of Flight Control Law Based on Global Sensitivity Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Liuli Ou ◽  
Lei Liu ◽  
Shuai Dong ◽  
Yongji Wang

To validate the robust stability of the flight control system of hypersonic flight vehicle, which suffers from a large number of parametrical uncertainties, a new clearance framework based on structural singular value (μ) theory and global uncertainty sensitivity analysis (SA) is proposed. In this framework, SA serves as the preprocess of uncertain model to be analysed to help engineers to determine which uncertainties affect the stability of the closed loop system more slightly. By ignoring these unimportant uncertainties, the calculation ofμcan be simplified. Instead of analysing the effect of uncertainties onμwhich involves solving optimal problems repeatedly, a simpler stability analysis function which represents the effect of uncertainties on closed loop poles is proposed. Based on this stability analysis function, Sobol’s method, the most widely used global SA method, is extended and applied to the new clearance framework due to its suitability for system with strong nonlinearity and input factors varying in large interval, as well as input factors subjecting to random distributions. In this method, the sensitive indices can be estimated via Monte Carlo simulation conveniently. An example is given to illustrate the efficiency of the proposed method.


2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
H. Saberi Najafi ◽  
A. Refahi Sheikhani ◽  
A. Ansari

We analyze the stability of three classes of distributed order fractional differential equations (DOFDEs) with respect to the nonnegative density function. In this sense, we discover a robust stability condition for these systems based on characteristic function and new inertia concept of a matrix with respect to the density function. Moreover, we check the stability of a distributed order fractional WINDMI system to illustrate the validity of proposed procedure.



2019 ◽  
Vol 16 (1) ◽  
pp. 172988141881995
Author(s):  
Francisco G Salas ◽  
Jorge Orrante-Sakanassi ◽  
Raymundo Juarez-del-Toro ◽  
Ricardo P Parada

Parallel robots are nowadays used in many high-precision tasks. The dynamics of parallel robots is naturally more complex than the dynamics of serial robots, due to their kinematic structure composed by closed chains. In addition, their current high-precision applications demand the innovation of more effective and robust motion controllers. This has motivated researchers to propose novel and more robust controllers that can perform the motion control tasks of these manipulators. In this article, a two-loop proportional–proportional integral controller for trajectory tracking control of parallel robots is proposed. In the proposed scheme, the gains of the proportional integral control loop are constant, while the gains of the proportional control loop are online tuned by a novel self-organizing fuzzy algorithm. This algorithm generates a performance index of the overall controller based on the past and the current tracking error. Such a performance index is then used to modify some parameters of fuzzy membership functions, which are part of a fuzzy inference engine. This fuzzy engine receives, in turn, the tracking error as input and produces an increment (positive or negative) to the current gain. The stability analysis of the closed-loop system of the proposed controller applied to the model of a parallel manipulator is carried on, which results in the uniform ultimate boundedness of the solutions of the closed-loop system. Moreover, the stability analysis developed for proportional–proportional integral variable gains schemes is valid not only when using a self-organizing fuzzy algorithm for gain-tuning but also with other gain-tuning algorithms, only providing that the produced gains meet the criterion for boundedness of the solutions. Furthermore, the superior performance of the proposed controller is validated by numerical simulations of its application to the model of a planar three-degree-of-freedom parallel robot. The results of numerical simulations of a proportional integral derivative controller and a fuzzy-tuned proportional derivative controller applied to the model of the robot are also obtained for comparison purposes.



Author(s):  
Rama K. Yedavalli

This paper presents new insight into the robust stability analysis of families of matrices described by convex combinations of Hurwitz stable 'vertex' matrices. Significant new insight is provided that removes many misconceptions that currently prevail in this problem formulation. In this connection, careful distinction is made between 'Structured' and 'Unstructured' convex combinations of matrices. The convex combinations arising from an uncertain matrix with interval parameters is labeled as 'structured' convex combinations whereas the convex combinations of 'user specified' Hurwitz stable vertex matrices are labeled as 'unstructured' convex combinations. It is clearly shown that the convex combination property in matrix case is dictated more by the nature of the 'vertex' matrices rather than by simply assigning values to the coefficients of the combination. From this analysis, it is clearly established that 'structured' and 'unstructured' convex combinations are two entirely different problem formulations and one is not a special case of the other as it is currently believed. Thus even the solution algorithms for checking the stability of these matrix families are different. After establishing this distinction, this paper then concentrates on the 'unstructured' case and provides a 'vertex solution' to a specific three vertex convex combination problem. The algorithm is illustrated with several examples. This contribution suggests that there is still considerable research needed to appreciably enhance the knowledge base in the important area of robust stability analysis of matrix families which arise in various applications.



2020 ◽  
Vol 106 ◽  
pp. 106208
Author(s):  
Boyi Chen ◽  
Jinbao Chen ◽  
Yanbin Liu ◽  
Hao Lei ◽  
Shan Jia


2014 ◽  
Vol 1006-1007 ◽  
pp. 711-714
Author(s):  
Hong Yang ◽  
Huan Huan Lü ◽  
Le Zhang

This paper investigates the problems of stability analysis and stabilization for a class of switched fuzzy discrete-time systems. Based on a common Lyapunov functional, a switching control method has been developed for the stability analysis of switched discrete-time fuzzy systems. A new stabilization approach based on a switching parallel distributed compensation scheme is given for the closed-loop switched fuzzy systems. Finally, the illustrative example is provided to demonstrate the effectiveness of the techniques proposed in this paper.



2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
Dapeng Tian ◽  
Bao Zhang ◽  
Honghai Shen ◽  
Jiaquan Li

The wave variable has been proposed to achieve robust stability against the time delay in bilateral control system. However, the influence of the force source on the overall system is still not clear. This paper analyzes this problem and proposes a supplement to the stability analysis for wave variable based bilateral control. Based on the scattering theory, it is pointed out that the design of force source decides the passivity of the two-port network of slave robot. This passivity influences the stability of overall system. Based on the characteristic equation and small gain theorem, it is clear that inappropriate designed force source in encoding the wave variable destroys the stability in the presence of time delay. A wave domain filter makes up for the broken stability. The principle of this reparation is explained in this paper. A reference is also provided by the analysis to design the parameter of the wave domain filter. Experiments prove the correctness and validity.



2021 ◽  
Vol 2070 (1) ◽  
pp. 012102
Author(s):  
V Venkatachalam ◽  
M Ramasubramanian ◽  
M Thirumarimurugan ◽  
D Prabhakaran

Abstract This paper presents an Investigation on the stability of network controlled temperature control system having Time-Invariant feedback delays, by utilizing a direct method for TDS stability analysis. A PI controller based stability analysis for temperature control system with Time invariant feedback loop delay has been constructed in this paper. The stability problem has been formulated based on the transfer function model of the closed loop system with various time delays. For different subsets of the controller parameters, based on the stability criterion’s maximal permissible bound of the network link delay that the closed loop system can accommodate without losing the stability has been computed. The effectiveness of the obtained result was validated on a benchmark temperature control system using MATLAB simulation software.



2009 ◽  
Vol 3 ◽  
pp. 119 ◽  
Author(s):  
Anderson Luiz Cavalcanti

RESUMO O presente trabalho tem o objetivo de apresentar uma análise em malha fechada do controlador Generalized Predictive Control (GPC). Esta análise visa observar, com detalhes, as características deste tipo de controlador. Os detalhes apresentados são de extrema importância na análise de estabilidade robusta. Alguns resultados de simulação são apresentados. PALAVRAS-CHAVE: Controle preditivo, sistemas em malha fechada. CLOSED-LOOP ANALYSIS OF GENERALIZED PREDICTIVE CONTROL (GPC) ABSTRACT This paper presents a closed loop analysys of Generalized Predictive Control GPC. This analysis observes, in details, the features of this kind of predictive controller The details showed are very important in robust stability analysis. Simulation results are shown. KEY-WORDS: Predictive control, closed-loop systems.



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