Vojtech Veselý

Robust model predictive control design with input constraints

The paper addresses the problem of designing a robust output/state model predictive control for linear polytopic systems with input constraints. The new predictive and control horizon model is derived as a linear polytopic system. Lyapunov function approach guarantees the quadratic stability and guaranteed cost for closed-loop system. The invariant set and an algorithm approach similar to Soft Variable-Structure Control (SVSC), ensures input constraints for the model predictive plant control system. In the proposed control scheme, the required on-line computation load is significantly less than in MPC literature, which opens the possibility to use these control design schemes not only for plants with slow dynamics, but also for faster ones.

Robust stability conditions for polytopic systems

The paper provides a survey of some recent robust stability conditions, their mutual comparisons, and presents new robust stability conditions for continuous- and discrete-time systems with convex polytopic uncertainty. Robust stability analysis is based on LMI conditions and parameter-dependent Lyapunov functions. The developed stability conditions are appropriate for output feedback design. Numerical examples thoroughly illustrate the power of the considered robust stability analysis methods and show which of them provides the less conservative results.

Robust output feedback controller design: genetic algorithm approach

This paper proposes guaranteed cost design of robust output feedback controller for continuous linear parametric uncertain systems. New necessary and sufficient conditions for static output feedback stabilizability of linear continuous time systems underly the design procedure. Proposed algorithms are computationally simple and tightly connected with the Lyapunov stability theory and the LQR optimal state feedback design. The proposed approach allows for prescribing the structure of the output feedback gain matrix (including the decentralized one) by the designer. New design method proposed in this paper, exploit genetic algorithm to design robust controller with guaranteed cost for polytopic linear continuous time systems. Numerical example is given to illustrate the performance of the proposed robust controller.

DESIGN OF ROBUST OUTPUT AFFINE QUADRATIC CONTROLLER

Abstract The paper addresses the problem robust output feedback controller design with guaranteed cost and affine quadratic stability for linear continuous time affine systems. The proposed design method leads to a non-iterative LMI based algorithm. A numerical example is given to illustrate the design procedure.

Design of robust gain-scheduled PI controllers

A novel approach to robust gain-scheduled controller design is presented. The proposed design procedure is based on the robust stability condition developed for an uncertain LPV system model introduced in this paper. The feasible design procedures are obtained in the form of BMI or LMI. The obtained design results and their properties are illustrated in simulation examples.

GAIN-SCHEDULED CONTROLLER DESIGN: VARIABLE WEIGHTING APPROACH

Abstract Among the most popular approaches to non-linear control is gain-scheduled (GS) controller, which can have better performance than robust and other ones. Our approach is based on a consideration that in linear parameter varying (LPV) system, scheduling parameters and their derivatives with respect to time are supposed to lie in a priori given hyper rectangles. To access the performance quality a new quadratic cost function is used, where weighting matrices are time varying depends on scheduled parameter. The class of control structure includes decentralised fixed order output feedbacks like PID controller. Numerical examples illustrate the effectiveness of the proposed approach.

Robust static output feedback controller LMI based design via elimination

Abstract A linear algebra result, known as Elimination Lemma, has been used to solve a large number of filtering and control problems. In this paper for special case we present a robust version of this result which simplifies, among other problems, the design of a robustly stabilizing static output feedback for linear polytopic systems.

Robust Output Feedback Design of Discrete-Time Systems - Linear Matrix Inequality Methods

Abstract Two novel linear matrix inequality (LMI) - based procedures to receive stabilizing robust output feedback gain are presented, one of them being modification of previous results of (Oliveira et al., 1999). The proposed robust control law stabilizes the respective uncertain discrete-time system described by polytopic model with guaranteed cost. The obtained results are compared with other LMI results from literature and illustrated on the example.

A frequency domain design technique for robust decentralized controllers

Abstract The paper proposes a new frequency domain approach to the design of robust decentralized controllers (DC) for continuous-time systems described by a set of transfer function matrices. To guarantee the nominal stability and the prespecified nominal performance, the recently developed DC design technique (Kozakova and Veselý, 2003) has been applied, adapted so as to guarantee the robust M -δ structure based stability conditions modified for the closed-loop system under decentralized controller as well. Unlike the standard robust approaches to the DC, this technique allows the inclusion of the nominal interactions into the nominal model; thus the conservativeness of the robust stability conditions is relaxed.

Robust Output Feedback Control Synthesis: LMI Approach

Abstract The paper addresses the problem of robust output feedback controller design with a guaranteed cost and parameter dependent Lyapunov function quadratic stability for linear continuous time polytopic systems. The proposed design methods lead to a non-iterative LMI based algorithm. Numerical example is given to illustrate the design procedure.