Unified analysis and design of robust disturbance attenuation algorithms using inherent structural equivalence

Model based disturbance compensating methods such as disturbance observer, adaptive robust controller, etc. are well known control structures for robust motion controller which can satisfy desired performance and robustness of high-accuracy positioning systems. In this paper, these are shown to be the same with different parameterizations. To do this, a general framework, called as RIC(robust internal-loop compensator) structure is proposed and the analysis of the conventional schemes is performed in the RIC framework. Through this analysis, it can be shown that there are inherent similarities between the schemes and advantages of the RIC in the viewpoint of controller design. This is verified through simulation works.