Browsing by Subject "Infinite Dimensional System"

Now showing 1 - 3 of 3

Open Access
Design of P and PI controllers for head positioning in hard disk drives with time delay
(2015) Koyuncu, Havva Buket
In today’s high performance positioning applications, due to stringent design objectives, it is very challenging to cope with input-output time delays. In Hard Disk Drive (HDD) servo system, the information flow between process and the controller is under a time delay. Typical state-space based modern control algorithms are not applicable to such infinite dimensional plants. In this thesis several control design objectives are considered and various types of stabilizing controllers are derived for this infinite dimensional plant. The objective of this thesis is to determine alternative simple (low order) controllers to the previously designed H∞ controller and controllers designed from Pade approximations. For this purpose, six different P and P I controllers for the unstable infinite dimensional plant are obtained. Comparisons of the controllers with each other are done and advantages of every approach are demonstrated.
Open Access
On mixed H2=H∞ controller design for systems with time delay
(2018-07) Ghomi, Meysam
This study discusses mixed H2=H∞ controller design problem for uncertain Linear Time-Invariant (LTI) systems with a time delay. More precisely, the goal is to find an internally stabilizing controller that minimizes the H2 performance measure subject to robust stability condition which bounds the H∞ norm of the weighted closed loop transfer function. Two different methods are used to find the optimal H2 controller. The first method is inspired from the H∞ control design to reduce the two block problem into one block. Second method, however is the implementation of the Mirkin's formula. These methods are compared and their pros and cons are discussed. The key point in the optimal controller is that, it is in Smith predictor form that includes an internal feedback in the form of an Finite Impulse Response (FIR) filter. These types of controllers are easy to implement and programmed in physical systems. A case study is considered to show the exact way to controller design. The simulation results and the effects of delay term on the performance measure are also provided.
Open Access
Stability analysis and controller design for the heat equation with time delayed feedback
(2010) Çalışkan, Sina Yamaç
In this thesis, the stability analysis for the system defined by the heat equation with time delayed feedback is performed. In the first part of the thesis, stability conditions in terms of LMI conditions which are obtained from the analysis in time domain, are explained. Necessary and sufficient conditions for stability are obtained using a frequency domain analysis. In the second part of the thesis, robust stability conditions are obtained for the system with parametric uncertainty. In the third part, an 퐻∞ controller design procedure is given for this type of plants described by the heat equation with time delayed feedback. Finally, the results are illustrated with simulations.