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A novel approach to robust controller design with input hard constraints is presented. The proposed design procedure contains robust stability condition based on the M-delta structure and it is used for system with additive uncertainty. The obtained results, illustrated on example, show the applicability of the designed robust controller and its ability to cope with model uncertainties.
Repetitive control (RC) is a widely used effective approach for periodic reference tracking and periodic disturbance rejection. In this paper, its use for periodic disturbance rejection and piecewise constant reference tracking is analyzed in a continuous-time framework. First, two previously proposed repetitive control structures, namely the basic repetitive controller and the current iteration repetitive...
Fractional-order models have been found to provide a more realistic and compact representation to real world and man-made systems. On the other side, fractional-order controllers have proved their efficacy over the conventional integer-order controllers by providing more flexibility in the design as well as by guaranteeing a more robust closed-loop configuration. In this paper, Bode's ideal loop transfer...
This paper proposes a model-based predictive sampled-data controller with a large fixed sampling rate h. Although the linear-time-invariant (LTI) plant is unknown, a nominal model is available. This nominal model is used to predict and compensate the influence of the large sampling using the measured information from the plant. The controller is designed on the basis of the nominal model. The robustness...
This paper present the Composite Nonlinear Feedback Control and Proportional Integral Sliding Mode Control (CNF-PISMC). The advantages of Composite Nonlinear Feedback Control are reducing overshoot; improve transient performance and fast response. The advantages of PISMC are to overcome uncertainties and steady state error in the system. The used of a boundary layer solution in the control law of...
In this paper, μ-synthesis is used to design a robust voltage controller for the cascaded boost dc-dc converter in continues conduction mode. The open loop is analyzed using a nominal frequency transfer function. The state space averaging technique and a structured uncertainty modeling approach are used to develop the controller model. The D-K iteration method is used to design a robustly performing...
In designs of a state feedback controller, the resulting system is desired to be robust stable, even when the plant has a time-delay and an uncertainty which have possible to not only reduce the controller performance, but to also destabilize the system. In this paper, we propose a design method to construct a robust linear quadratic regulator (robust LQR) for a neutral system with a time-varying...
In this paper, we discuss event-triggering scheme with sliding mode control where sensors are distributed over network. Here, a decentralized event-triggering mechanism is proposed where event is observed at each sensor nodes with local information for possible triggering and control update is done whenever a centralized event is triggered. In order to achieve this, the states are sampled at any one...
Recently the authors have shown that the general design ideas for robust controllers that are suitable for stable systems with step reference and disturbance signals are valid for more general classes of signals: in [1] for linear combinations of sinusoids and in [2] for linear combinations of sinusoids and polynomials and their products. The analysis in [1] is for parabolic systems in the time domain...
A discontinuous control law exponentially stabilizing a simple nonholonomic system is discussed and analyzed in detail. Basic properties, such as existence and uniqueness of the closed loop system trajectories, and simple robustness issues are studied. Continuous modifications of the considered discontinuous control law are proposed and discussed in detail. The considered controller is representative...
In this paper, an approach of designing optimal controllers for minimal overshoot and undershoot within specific settling time and decreasing rate is presented for SISO discrete-time systems. Utilizing the linear programming the optimal controllers are achieved conveniently when the zeros and poles inside or on the unit disc and the specific input signal are known previously. Also, the unity of optimal...
Polytopic models cover a large class of nonlinear dynamic systems. An algorithm is proposed that partitions the state-space into a number of disjoint clusters on which a gain-scheduling controller is defined. Then, an iterative synthesis algorithm based on LMIs is developed that guarantees globally robust stability of the closed loop system. Finally, an analysis method is presented that makes it possible...
In this paper we consider frequency properties and robustness of H∞ suboptimal state feedback. It is shown that in spite of large gain and phase margins (at the plant input), the closed-loop H∞ suboptimal system may not be robust in the sense that small parameter variations in the plant and/or the controller matrices may lead to instability. This situation is illustrated by a simple example.
In this paper, a non linear autopilot for a missile pitch axis is designed over a wide flight envelope. The controller is obtained by a Linear Parametrically Varying (LPV) synthesis applied to the H¥/loop-shaping criterion. The resulting controller depends on the angle of attack, the Mach number and the altitude. Robust stability and performance are firstly checked by means of linear analysis and...
This paper addresses the issue of robustness of the LMS-driven Adaptive Periodic Noise Canceller (APNC) in a closed-loop system. The concept of robustness provides a framework within which it is possible to make a useful assessment of algorithm performance. By adopting an analysis based on H∞-theory, conditions are shown under which the APNC, driven by the LMS algorithm, will exhibit robust performance...
A practical example of multivariable control analysis and design for a pilot plant within Individual Channel Analysis and Design (ICAD) framework is presented. The pressure-level plant is used for studying the dynamics of variables like gas pressure and liquid level that often occur in the process industries. The device is very problematic since it is highly nonlinear and it is not diagonal dominant...
The problem of bounded disturbance rejection for linear impulsive systems with polytopic uncertainties is considered in this paper. By using the Lyapunov function and positively invariant set method, a sufficient condition for robustly internal stability and L1-performance of the impulsive systems is obtained in terms of linear matrix inequalities. A simple algebraic approach to the design of a linear...
This paper focuses on a path-following problem for a suitable class of Chaplygin-like non linear uncertain systems. A feedforward/feedback strategy is proposed where the feedforward action is based on an exact dynamic inversion of the nominal system and the feedback correction depends on the error of the actual output with respect to the path to be followed. A convergence analysis of the resulting...
We consider robust adaptive control designs for relative degree one, minimum phase linear systems of known high frequency gain. The designs are based on the dead-zone and projection modifications, and we compare their performance w.r.t. a worst case transient cost functional penalising the L∞ norm of the output, control and control derivative. If a bound on the L∞ norm of the disturbance is known,...
In this paper, one method of robust control based on sliding mode and fuzzy logic techniques is presented. It combines hierarchical control with high gain approach for multivariable and nonlinear systems; in order to eliminate chattering in presence of disturbances. Simulation results are presented to illustrate the applicability of the approach.
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