Design of direct MRAC augmented with 2 DoF PIDD controller: An application to speed control of a servo plant

Abstract

An adaptive control with reference model provides the solution for uncertainty in dynamics, transient performance characteristics of autonomous systems. The high frequency oscillation and poor settling time are the important challenges in adaptive control methodology. This article proposes the Model Reference Adaptive Control (MRAC) augmented with Proportional Integral Double Derivative (PIDD) controller for a solution of such kind of problems. This proposed multi-loop structure consists of two loops: a primary outer loop executes MRAC with two adjustment mechanism and a secondary inner loop act as a normal closed loop 2 DoF PIDD controller with plant dynamics. The function of 2 DoF PIDD controller is act as a filter for primary adaptive loop to control the high frequency oscillations and pulsating signals. This cascade or multi-loop structure will makes the secondary loop is more stable. The tuning of 2 DoF PIDD parameters again a challenging task due to the presence of extra two parameters and it was done by particle swarm optimization (PSO) algorithm. The effectiveness of the proposed methodology has been tested in servo plant model.