Output Regulation of n-Link Robotic Manipulator Using Feedback Linearizable Systems under the Approach of Cascade High Gain Observers

Abstract

The High gain observer (HGO) is found to be a very effective tool against output feedback control. However, this observer faces the numerical challenge of having peaking phenomena for high order systems. A new class of observer named Cascade high gain observer (CHGO), is manipulated for high order systems. CHGO is a useful technique for accurate estimation of the higher unknown dimensions of the plant. The observers having lower dimension have saturation function in between them in CHGO. Let the plant has dimension ρ and parameter of high gain K, then the gain for the CHGO is limited to an order of K in contrast to the gain of the HGO having Kρ-1. In this research, output regulation of a feedback linearizable system was achieved under a CHGO approach and results are compared with the high gain observer results. It is worthy to mention here that while using CHGO the peaking was limited to the order of (1/ϵ) for plants of higher dimension.