Subspace based direct adaptive ℋ︁∞ control

This paper presents extensions of the model free subspace based ℋ∞ control approach. In particular, a fast algorithm for computing a subspace predictor from experimental data is introduced. The paper also describes a fast algorithm for updating the subspace predictor when new experimental data are available. These algorithms can be applied in conjunction with model free subspace based ℋ∞ control in order to create a novel adaptive control law. A defining feature of this control law is that an estimate of achievable performance is maintained throughout the operation of the closed-loop system. These algorithms are used to demonstrate the closed-loop control of a flexible structure. Copyright © 2001 John Wiley & Sons, Ltd.