Designing an Indirect Adaptive Multiple Controller for LTI Systems with Large Time-Varying and Unknown Delays in Control Input Based on Online Estimation of Delay by Kalman Filtering

The present study presents an adaptive controller for LTI systems with an unknown and time-variant input time delay with the purpose of tracking. Due to the wide area considered for time delay variations, the structure of the proposed controller is considered to be in the form of Multiple Adaptive Control (MAC). The presented adaptive control system is of indirect type, i.e., at any moment, one band of time delay is first identified using a proposed estimator, and then the main control signal, which is a linear combination of multiple controllers output, is formed with a switching rule in the supervisory subdivision. In fact, each multiple controller in the MAC structure with fit weights participates in forming the main control signal. The multiple controllers used in this study are of PID type. It should be noted that the parameters for the individual multiple controllers, for the system under control, are adjusted offline and proportional to its corresponding time-delay sub-band using a genetic algorithm. Finally, simulation results show the relatively desirable performance of the proposed control system and observer in facing with wide unknown and time-variant delays.