Stable Output Feedback Control Research Articles

Combustion Control System Design of Diesel Engine via ASPR based Output Feedback Control Strategy with a PFC

In this paper, a design method of an output feedback control system with a simple feedforward input for a combustion model of diesel engine will be proposed based on the almost strictly positive real-ness (ASPR-ness) of the controlled system for a combustion control of diesel engines. A parallel feedforward compensator (PFC) design scheme which renders the resulting augmented controlled system ASPR will also be proposed in order to design a stable output feedback control system for the considered combustion model. The effectiveness of our proposed method will be confirmed through numerical simulations.

Stable adaptive output feedback controller for a class of uncertain non‐linear systems

This study deals with design of an adaptive output feedback tracking controller for a class of non-linear systems with unknown fixed control direction. By using neural networks and deriving adaptive rules based on the steepest descent algorithm, the authors present a stable output feedback control scheme, which is applicable to a wide class of unknown complicated non-linear systems. Therefore an approach based on the dynamic back propagation algorithm is proposed to develop the adaption laws for systems with more general model structure. Using Lyapunov's direct method, uniformly ultimately boundedness of all signals of the closed-loop system is also ensured. Moreover, it is shown that the bounds on the tracking errors depend on the designing parameters. Hence, an arbitrarily small tracking error can be achieved by adjusting the parameters properly. Finally, simulation results performed on a non-affine uncertain non-linear system having internal dynamics are given to demonstrate the effectiveness of the proposed scheme and the theoretical discussions.

Output Feedback Control for a Class of Switched Fuzzy Systems

The output feedback control problem is addressed for a class of switched fuzzy Systems. Using multiple Lyapunov function method and switching law, the relevant closed-loop system is asymptotically stable, with the switching law designed to implement the global asymptotic stability. The sufficient conditions to ensure the output feedback asymptotically stable output feedback control of closed-loop system are studied. The sufficient condition is transformed into Linear Matrix Inequality (LMI) problem which are more solvable. Finally, a numerical simulation example is employed to illustrate the effectiveness and the convergence of the design methodologies.

Robust $H^{\infty }$ Control of an Uncertain System Via a Stable Output Feedback Controller

This technical note presents a new approach to the robust control of an uncertain system via a stable output feedback controller. The uncertain systems under consideration contain structured uncertainty described by integral quadratic constraints. The controller is designed to achieve absolute stabilization with a specified level of disturbance attenuation. The main result involves solving a state feedback version of the problem by solving an algebraic Riccati equation dependent on a set of scaling parameters. Then two further algebraic Riccati equations are solved, which depend on a further set of scaling parameters.

A novel adaptive control algorithm based on non-linear Laguerre—Volterra observer

By expanding each kernel using an orthonormal Laguerre series, a Volterra functional series is used to represent the input—output relation of a non-linear dynamic system. When Volterra series and Laguerre series truncations are allowed, an appropriate choice of the Laguerre filter pole permits a description of the process dynamics with a small number of parameters. Feeding back the error of the outputs of the plant and the model, we design a novel non-linear state observer, based on which a stable output feedback control law is derived for both regulator and tracking problems. To support this algorithm, we present the theoretical analyses of its nominal stability, which allows us to obtain the state feedback gain and the observer gain solely by solving two linear matrix inequalities (LMIs). In addition, another theorem is also given to show its capability of minimizing the steady-state tracking errors. To handle more complex dynamics, we improve the standard recursive least square estimation (RLSE) identification method to a normalized one with guaranteed convergence. Finally, control simulations on a benchmark problem — a continuous stirring tank reactor (CSTR) process — and experiments on a chemical reactor temperature control system are performed. This method, especially its essential idea of a Volterra non-linear observer, has shown great potential for the control of a large class of non-linear dynamic systems.

Exponentially Stable Output Feedback Control of Induction Motor

A new nonlinear output feedback control algorithm is designed for a full order model of an induction motor. The control algorithm is based on the concept of indirect field orientation and guarantees global exponential tracking of speed and flux reference trajectories in presence of unknown constant load torque. Besides, it provides new properties on system dynamic performance and has simple implementation.

Semiglobal exponential output feedback control of ships

This paper describes a semiglobal exponentially stable output feedback control law for automatic heading control of ships described by a nonlinear model. Only compass (yaw angle) feedback is used. The yaw rate signal is reconstructed by a linear observer. A wave filter is included in the observer to reduce wear and tear on the rudder servo due to first-order wave-induced disturbances. Integral action is included in the control law to compensate for wave drift (second-order wave disturbances), low-frequency wind, and current disturbances. The performance and robustness of the controller are demonstrated in a simulation study of two medium-sized ships.