Abstract
In this paper, a stability-driven optimal disturbance observer (DO) is proposed. The proposed method does not require any plant inverse dynamics to detect introduced disturbances or a stabilizing Q filter. It does not require additional compensators to resolve causality problems, due to the relative degree, or filters to solve instability problems of non-minimum phase plants. Using this method enables wideband and narrowband disturbances to be attenuated by simply multiplying the corresponding peak filters by the baseline weight function. Furthermore, the proposed DO guarantees the stability of closed-loop systems because the already designed outer-loop systems are considered as a target plant to be stabilized and because of the Lyapunov stability-based H∞ control. In the application example, it was confirmed that the proposed method is effective, and the position error signals were improved by 20.9% in commercial hard disk drives and 36.6% in optical image stabilization systems.
Highlights
One of the main causes of tracking performance degradation in the motion control systems is a disturbance
A star tracker system based on a two-axis inertially stabilized platform, which was controlled by a disturbance observer (DO), was proposed for improving the stability accuracy [8]
An iterative learning control (ILC)-based DO was used to compensate for the difference between the ILC prediction and the true disturbance
Summary
One of the main causes of tracking performance degradation in the motion control systems is a disturbance. Unlike a conventional DO, in that study, the proposed high-order DO guarantees fast convergence of the estimated error To reduce both noise and uncertainty, a modified DO was proposed, and the method was applied to brushless DC motor drive systems [5]. As an another usage of the LMI approach, there is a loop shaper in the frequency domain, such as the H∞ control, and numerous studies have been conducted using these features To achieve their unique goals, the researchers have suggested new cost functions to be minimized, even suggesting modified design frameworks. It is not simple to apply the DO design to the standard LMI framework because the closed loop systems are mixed with a plant, a conventional controller, and a DO.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
