Robust Gain-Scheduling Output Feedback Control of State-Delayed LFT Systems Using Dynamic IQCs

2015 ◽  
Author(s):  
Chengzhi Yuan ◽  
Fen Wu ◽  
Chang Duan
Keyword(s):  
Feedback Control ◽  
Output Feedback ◽  
Output Feedback Control ◽  
Gain Scheduling ◽  
Linear Matrix ◽  
Feedback Controllers ◽  
State Delay ◽  
Synthesis Conditions ◽  
Output Behavior ◽  
Gain Scheduled

This paper is concerned with the robust gain-scheduling output feedback control problem for a class of linear parameter-varying systems with time-varying state delay. The controlled plant under consideration is described as a linear fractional transformation (LFT) model of scheduling parameters. Dynamic integral quadratics (IQCs) are employed to characterize the input-output behavior of the state-delay nonlinearity. The robust stability and the L2-gain performance are first analyzed using quadratic Lyapunov function. Then, the design of dynamic output-feedback controllers robust against the plant state-delay nonlinearity and gain-scheduled by parameters is examined. The synthesis conditions of such robust gain-scheduling controllers are formulated in terms of linear matrix inequalities (LMIs) plus a line search, which can be solved effectively using existing algorithms. A numerical example has been used to demonstrate the effectiveness and advantages of the proposed approach.

scholarly journals Static Output-Feedback Control for Vehicle Suspensions: A Single-Step Linear Matrix Inequality Approach

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Josep Rubió-Massegú ◽  
Francisco Palacios-Quiñonero ◽  
Josep M. Rossell ◽  
Hamid Reza Karimi
Keyword(s):  
Feedback Control ◽  
Output Feedback ◽  
Output Feedback Control ◽  
Vehicle Suspension ◽  
Linear Matrix ◽  
Static Output Feedback ◽  
Matrix Inequality ◽  
Feedback Controllers ◽  
Feedback Information ◽  
Static Output

In this paper, a new strategy to design static output-feedback controllers for a class of vehicle suspension systems is presented. A theoretical background on recent advances in output-feedback control is first provided, which makes possible an effective synthesis of static output-feedback controllers by solving a single linear matrix inequality optimization problem. Next, a simplified model of a quarter-car suspension system is proposed, taking the ride comfort, suspension stroke, road holding ability, and control effort as the main performance criteria in the vehicle suspension design. The new approach is then used to design a static output-feedbackH∞controller that only uses the suspension deflection and the sprung mass velocity as feedback information. Numerical simulations indicate that, despite the restricted feedback information, this static output-feedbackH∞controller exhibits an excellent behavior in terms of both frequency and time responses, when compared with the corresponding state-feedbackH∞controller.

Robust Gain-Scheduling Output Feedback Control With Noisy Scheduling Parameters

2015 ◽  
Author(s):  
Ali Khudhair Al-Jiboory ◽  
Guoming Zhu
Keyword(s):  
Output Feedback ◽  
Sufficient Conditions ◽  
Output Feedback Control ◽  
Gain Scheduling ◽  
Linear Matrix ◽  
Synthesis Methods ◽  
Matrix Inequalities ◽  
Feedback Controllers ◽  
Comparison Results ◽  
H2 Performance

Robust Gain-Scheduling (RGS) control strategy has been considered in this paper. In contrast to the conventional gain-scheduling synthesis methods, the scheduling parameters are assumed to be inexactly measured. This is a practical assumption since measurement noise is inevitable even with very accurate sensors. Multi-simplex modeling approach was used to model the scheduling parameters and their uncertainties in a convex domain. Sufficient conditions in terms of Parametrized Linear Matrix Inequalities (PLMIs) for synthesizing dynamic output-feedback controllers are derived. The resulting controller not only guarantees robust stability and H2 performance but also ensures robustness against scheduling parameters uncertainties. The effectiveness of the developed conditions is demonstrated through numerical example with simulation and comparisons with existing approaches from literature. The comparison results confirm that the developed approach outperforms the existing ones considerably.

H ∞ Control for Continuous-Time Switched Linear Systems

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Grace S. Deaecto ◽  
José C. Geromel
Keyword(s):  
Feedback Control ◽  
Linear Systems ◽  
Output Feedback ◽  
Continuous Time ◽  
Design Problem ◽  
State Feedback ◽  
Output Feedback Control ◽  
Control Design ◽  
Linear Matrix ◽  
Switched Linear Systems

This paper deals with the output feedback H∞ control design problem for continuous-time switched linear systems. More specifically, the main goal is to design a switching rule together with a dynamic full order linear controller to satisfy a prespecified H∞ level defined by the L2 gain from the input to the output signal. Initially, the state feedback version of this problem is solved in order to put in evidence the main difficulties we have to face toward the solution of the output feedback control design problem. The results reported in this paper are based on the so called Lyapunov–Metzler inequalities, which express a sufficient condition for switched linear systems global stability. The solution of the previously mentioned output feedback control design problem through a linear matrix inequality based method is the main contribution of the present paper. An academic example borrowed from literature is used for illustration.

Delayed Output Feedback Control for Nonlinear Systems With Fuzzy Observers

2012 ◽  
Author(s):  
Mansour Karkoub ◽  
Tzu Sung Wu
Keyword(s):  
Feedback Control ◽  
Nonlinear System ◽  
Nonlinear Systems ◽  
Output Feedback ◽  
Tracking Error ◽  
Sufficient Conditions ◽  
Output Feedback Control ◽  
Linear Matrix ◽  
External Disturbances ◽  
Control Scheme

In this paper, the design problem of delayed output feedback control scheme using two-layer interval fuzzy observers for a class of nonlinear systems with state and output delays is investigated. The Takagi-Sugeno type fuzzy linear model with an on-line update law is used to approximate the nonlinear system. Based on the fuzzy model, a two-layer interval fuzzy observer is used to reconstruct the system states according to equal interval output time delay slices. Subsequently, a delayed output feedback adaptive fuzzy controller is developed to override the nonlinearities, time delays, and external disturbances such that the H∞ tracking performance is achieved. The linguistic information is developped by setting the membership functions of the fuzzy logic system and the adaptation parameters to estimate the model uncertainties directly for using linear analytical results instead of estimating nonlinear system functions. The filtered tracking error dynamics are designed to satisfy the Strictly Positive Realness (SPR) condition. Based on the Lyapunov stability criterion and linear matrix inequalities (LMIs), some sufficient conditions are derived so that all states of the system are uniformly ultimately bounded and the effect of the external disturbances on the tracking error can be attenuated to any prescribed level and consequently an H∞ tracking control is achieved. Finally, a numerical example of a two-link robot manipulator is given to illustrate the effectiveness of the proposed control scheme.

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