Browsing by Subject "Stability margins"

Now showing 1 - 4 of 4

Open Access
Controller redesign for delay margin improvement
(Elsevier, 2020-01) Gündeş, A. N.; Özbay, Hitay
Two important design objectives in feedback control are steady-state error minimization and delaymargin maximization. For many practical systems it is not possible to have infinite delay margin andzero steady state error for unit step reference input. This paper proposes a re-design method forcontrollers initially designed to satisfy the steady-state error requirement. The objective is to makestructural changes in the controller so that a lower bound of the delay margin is improved withoutaffecting the steady-state error. The order of the new controller is (ν+1) higher than the order of theoriginal controller, whereνis the number of unstable poles of the plant.
Open Access
Delay margin optimization for systems with ınternal delayed feedback
(Elsevier, 2021-07-16) Özbay, Hitay
In this brief paper, controller design for delay margin optimization is considered for systems with internal feedback delays (systems with delays in the state variables). Similar to existing results on delay margin optimization for finite dimensional systems with I/O delays, it is shown that the problem considered can be solved by using Nevanlinna-Pick interpolation involving non-minimum phase zeros of the plant.
Open Access
Low-order controller design for haptic systems under delayed feedback
(2012) Liacu, B.; Koru, A. T.; Özbay, Hitay; Niculescu, S. -I.; Andriot, C.
In this paper, we consider PD controller design for haptic systems under delayed feedback. More precisely, we present a complete stability analysis of a haptic system where local dynamics are described by some second-order mechanical dynamics. Next, using two optimization techniques (H ∞ and stability margin optimization) we propose an optimal choice for the controller gains. The derived results are tested on a three degree of freedom real-time experimental platform to illustrate the theoretical results. © 2012 IFAC.
Open Access
Strongly stabilizing controllers for a two-link robotic system
(2024-01) Andaç, Adile Merve
Strong stabilization is defined as finding a stable controller that stabilizes the feedback system for a given plant. This study addresses the strong stabilization of a robotic system called the “acrobot”, which is a two-linked underactuated planar robot system. The linearized system is fourth-order, with two poles and one zero in the right half-plane. In this thesis, stable second-order controllers designed with different methods have been investigated for this system. The sta-bility margins are analyzed with respect to various free parameters. In addition, the time-domain transient response analysis is illustrated through simulations. Furthermore, the effects of nonlinearities are studied by estimating the region of attraction for each linear controller considered.