Singular perturbations and order reduction in control theory - An overview
Automatica (Journal of IFAC)
Brief paper: Stability analysis of adaptively controlled systems subject to bounded disturbances
Automatica (Journal of IFAC)
Preventing bursting in approximate-adaptive control when using local basis functions
Fuzzy Sets and Systems
A fully adaptive decentralized control of robot manipulators
Automatica (Journal of IFAC)
On the performance of high-gain observers with gain adaptation under measurement noise
Automatica (Journal of IFAC)
Paper: Decentralized adaptive control of interconnected systems with reduced-order models
Automatica (Journal of IFAC)
Automatica (Journal of IFAC)
Brief Robust high-order tuner of simplified structure
Automatica (Journal of IFAC)
Automatica (Journal of IFAC)
Design of a unified adaptive fuzzy observer for uncertain nonlinear systems
Information Sciences: an International Journal
Hi-index | 22.16 |
The effects of unmodeled high frequency dynamics and bounded disturbances on stability and performance of adaptive control schemes are analyzed. Five possible types of instability mechanisms-parameter drift, 'linear' instability, 'fast adaptation' instability, 'high frequency' instability, and 'throughput' instability-are analyzed using simple examples. A procedure is used to construct Lyapunov-like functions for a modified adaptive controller applied to a dominant plant of relative degree one, in the presence of parasitics and disturbances, and obtain sufficient conditions under which none of the five types of instability can occur. The modified scheme is robust in the sense that it guarantees the existence of a large region of attraction from which all the trajectories remain bounded and the state errors converge exponentially to a much smaller residual set. The size of the region of attraction depends on the speed of parasitics in such a way that as the parasitics become infinitely fast, the region of attraction becomes the whole space.