A Multiple-Model MRAC Scheme for Discrete-Time Multivariable Systems with Uncertain Actuation Delays

In this paper, a novel multiple-model based model reference adaptive control (MRAC) scheme is designed for discrete-time multivariable systems with uncertain actuation delays. Such an adaptive control scheme is capable of handling the structure uncertainties caused by uncertain actuation delays. A set of system structure uncertainty patterns is formed, and corresponding to each pattern, a reference model system is chosen. Multiple direct adaptive controllers are designed for the system under different structure uncertainties, based on different reference model systems. A control switching mechanism is designed with multiple modified performance indexes based on normalized estimation errors, which is desirable for selecting the most appropriate controller. The results shows an important step forward in employing the minimal amount of necessary prior knowledge to design a stable control scheme for a linear multivariable system.