Continuous-time Adaptive Control Research Articles

A continuous-time adaptive controller with integral action

This note shows how a continuous-time adaptive control law can be constructed which automatically includes integral action. The control law is based on the internal model principle. Global convergence can be readily established for the algorithm using standard methods.

A Frequency Domain Analysis of Direct Adaptive Pole Placement Algorithms in the Presence of Unmodelled Dynamics

This paper examines a general class of direct adaptive pole placement algorithms in the presence of unmodelled high frequency dynamics. The analysis is broken into three stages. The first stage addresses the robustness of the fixed control structure on which most continuous time adaptive control schemes are based. The second stage looks at the effect of unmodelled dynamics on the estimation model used in equation error formulations of continuous time algorithms. The last stage looks specifically at the identification process.

Continuous time adaptive identification and control algorithms via newly developed adaptive laws

In the first part of this paper, a continuous time adaptive identification algorithm via newly developed adaptive laws is presented. The principle of the algorithm is very simple, nevertheless the convergence property is quite excellent. In the second half part, two continuous time adaptive control algorithms via adaptive laws, as were used for adaptive identification, are presented. A new canonical form for adaptive control is first developed for this purpose. The design procedure for adaptive control systems requires neither positive realness nor augmented error signals and can be applied irrespective of the relative degree of the plant transfer function.

Stability Analysis of Continuous-Time Adaptive Control Systems

The stability properties of a fairly general continuous-time adaptive control scheme are analyzed. Sufficient conditions for $L^\infty $-stability in the presence of disturbances are given. The stability results are used to prove convergence of the process outputs in the disturbance-free case, without requiring any a priori stability assumptions.

Unification of some continuous-time adaptive control schemes

Model reference adaptive regulators based on input-output descriptions are examined. By reinterpreting the concept of "augmented error," it is shown that there are no essential differences between the model reference adaptive algorithms and the self-tuning regulators. Both types of schemes can be thought of as composed of a parameter estimator and a control law, based on the parameter estimates. It is shown that many schemes proposed are special cases of a general algorithm. The positive real condition for model reference adaptive systems is also examined. It is shown that this condition is a consequence of the choice of the estimator and that it is not crucial for stability.