Joseph R. Corrado

Robust resilient dynamic controllers for systems with parametric uncertainty and controller gain variations

A feedback control design problem involving structured plant parameter uncertainties and controller gain variations is considered. Specifically, the robust fixed-structure guaranteed cost controller synthesis framework is extended to address the design of robust resilient fixed-order (i.e., full- and reduced-order) dynamic controllers for systems with structured parametric uncertainty and controller gain uncertainty. Several examples are provided which clearly demonstrate the need for robust resilient control.

Resilient dynamic controller design via quadratic Lyapunov bounds

One of the fundamental problems in feedback control design is the ability of the control system to maintain stability and performance in the face of system uncertainties. To this end, elegant multivariable robust control design frameworks such as /spl Hscr//sub /spl infin// control, /spl Lscr//sub 1/ control, and /spl mu/ synthesis have been developed to address the robust stability and performance control problem. An implicit assumption inherent in these design frameworks is that the controller will be implemented exactly. In a paper by Keel and Bhattacharyya (1996) it was shown that even though such frameworks are robust with respect to system uncertainty, they are extremely fragile with respect to errors in the controller coefficients. In this paper, we extend the fixed-structure controller synthesis approach to develop non-fragile or resilient controllers to controller gain variations.

Static output feedback controllers for systems with parametric uncertainty and controller gain variation

A feedback control design problem involving structured plant parameter uncertainties and controller gain variations is considered. Specifically, the robust guaranteed cost controller synthesis framework is extended to address the design of robust resilient static output feedback controllers for systems with structured parametric uncertainty and controller gain uncertainty.

State space modeling and robust reduced-order control of combustion instabilities ☆

Abstract Thermoacoustic instabilities in combustion processes can have adverse effects on system performance. In this paper we formulate the problem of active control of combustion instabilities in a form that lends itself to the application of robust feedback control design. Using an uncertain state-space combustion system model, the parameter-dependent Lyapunov function framework for robust fixed-order controller design developed by Haddad and Bernstein is used to design high-performance reduced-order robust controllers for suppressing thermoacoustic oscillations in combustion chambers.

Robust fixed-structure controller synthesis using the implicit small-gain bound

Abstract In this paper we explore the applicability of the implicit small-gain guaranteed cost bound for controller synthesis. For flexibility in controller synthesis, we adopt the approach of fixed-structure controller design which allows consideration of arbitrary controller structures, including order, internal structure, and decentralization. A numerical example that has been addressed in the literature by means of alternative guaranteed cost bounds is presented to demonstrate the fixed-structure/implicit small-gain approach to robust controller synthesis.

Fixed-order dynamic compensation for axial flow compression systems

We develop linear fixed-order (i.e., full and reduced order) pressure rise feedback dynamic compensators for axial flow compressors with throttle valve actuation. Unlike the nonlinear static controllers proposed in the literature possessing gain at all frequencies, the proposed dynamic compensators explicitly account for compressor performance versus sensor accuracy, compressor performance versus processor throughput, and compressor performance versus disturbance rejection. Furthermore, the proposed controller is predicated on only pressure rise measurements, providing a considerable simplification in the sensing architecture over the bifurcation-based and backstepping controllers proposed in the literature.

Stable ?2-optimal controller synthesis

This paper considers fixed-structure stable ℋ2-optimal controller synthesis using a multiobjective optimization technique which provides a trade-off between closed-loop performance and the degree of controller stability. The problem is presented in a decentralized static output feedback framework developed for fixed-structure dynamic controller synthesis. A quasi-Newton/continuation algorithm is used to compute solutions to the necessary conditions. To demonstrate the approach, two numerical examples are considered. The first example is a second-order spring–mass–damper system and the second example is a fourth-order two-mass system, both of which are considered in the stable stabilization literature. The results are then compared with other methods of stable compensator synthesis. Copyright

State space modeling and robust reduced-order control of combustion instabilities

Thermoacoustic instabilities in combustion processes can have adverse effects on system performance. In this paper we formulate the problem of active control of combustion instabilities in a form that lends itself to the application of robust feedback control design. Using the uncertain state-space system model, the parameter-dependent Lyapunov function framework for robust fixed-order controller design developed by Haddad and Bernstein (1995) is used to design high performance reduced-order robust controllers for suppressing thermoacoustic oscillations in combustion chambers.

Pressure feedback reduced-order dynamic compensation for axial flow compression systems

We develop linear, fixed-order (i.e., full and reduced-order) pressure rise feedback dynamic compensators for axial flow compressors. Unlike the nonlinear static controllers proposed in the literature possessing gain at all frequencies the proposed dynamic compensators explicitly account for compressor performance versus sensor accuracy, compressor performance versus processor throughput, and compressor performance versus disturbance rejection. Furthermore, the proposed controller is predicated on only pressure rise measurements, providing a considerable simplification in the sensing architecture over the bifurcation-based and backstepping controllers proposed in the literature.

Robust reduced-order control of combustion instabilities

Thermoacoustic instabilities in combustion processes can have adverse effects on system performance. In this paper we formulate the problem of active control of combustion instabilities in a form that lends itself to the application of robust feedback control design. Using the uncertain state-space system model, the parameter-dependent Lyapunov function framework for robust fixed-order controller design developed by Haddad and Bernstein (1995) is used to design high performance reduced-order robust controllers for suppressing thermoacoustic oscillations in combustion chambers.