title: Two-layer observer based control for a class of uncertain systems with multi-frequency disturbances.
abstract: A novel disturbance estimation approach is presented for a class of uncertain systems subject to multiple-sinusoidal disturbances with unknown frequencies. Different from existing results on disturbance observer based control (DOBC), a new methodology with a two-layer observer structure is developed to effectively estimate and reject the disturbances. In the proposed control architecture, an auxiliary observer is derived to generate a disturbance representation in a parametric uncertainty form. Furthermore, the unknown parameters can be reduced to a constant vector with the dimension of the number of harmonic components in the disturbances. Then an augmented observer is designed to estimate the corresponding unknown parameters of the disturbances. As a result, the uncertain systems with disturbances constituting of multiple unknown-frequency sinusoidal components can be controlled within the DOBC framework, where asymptotic stability can be guaranteed. The proposed approach is successfully validated on a robotic manipulating example.
authors.affiliation: School of Electronic Information Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi 030024, China.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Wen
authors.affiliation: Key Laboratory of High-efficiency and Clean Mechanical Manufacture, Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, China; School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China. Electronic address: pengyan2007@gmail.com.
authors.forename: Peng
authors.initials: P
authors.lastname: Yan
keywords: Disturbance estimation and rejection; Disturbance observer based control; Robotic manipulator; Two layer observer