Estimation and Adaptive Control Algorithms [About This Issue

Abstract

This issue of IEEE Control Systems Magazine contains two feature articles that provide extensive tutorials on advanced control and estimation algorithms. The first feature, “Retrospective Cost Adaptive Control-Pole Placement, Frequency Response, and Connections with LQG Control,” by Yousaf Rahman, Antai Xie, and Dennis S. Bernstein, presents an in-depth analysis of the retrospective cost adaptive control (RCAC) algorithm. A primary goal of the article is to present RCAC in sufficient detail so that readers can grasp all of the key steps in the algorithm. The RCAC approach minimizes the residual between an intercalated injection and the performance measure based on a target model that must be chosen during the design. The article highlights that RCAC uses extremely limited modeling in - formation about the system, and this target model incorporates the required modeling information. Several numerical examples are used to demonstrate adaptive pole placement using RCAC; compare RCAC with discrete-time linear quadratic Gaussian control; and investigate the robustness of the algorithm to sensor noise, model error, and time-varying dynamics. These examples include plants with various types of stability, control architectures, and exogenous signals, along with several problem objectives.