Browsing by Subject "PID control"
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Item 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.Item Open Access A new PI and PID control design method and its application to active queue management of TCP flows(Bilkent University, 2007) Üstebay, DenizPID controllers are continuing to be used in many control applications due to their simple structures. Design of such controllers for unstable systems with time delays is an active research area. Recently, stabilizing PI and PD controllers for a class of unstable MIMO (multi-input multi-output) systems with input/output delays have been investigated and allowable controller gain intervals for such controllers have been maximized. Motivated by these studies, this thesis proposes a new method for tuning the parameters of PI, PD and PID controllers for integrating processes with time delays. The method is based on selecting the centers of the maximized gain intervals as the controller gains for the purpose of obtaining optimal controllers. As an application of this method, controllers for AQM (Active Queue Management) of TCP (Transmission Control Protocol) flows have been designed. AQM is a congestion control method used in computer networks to increase link utilization with less queueing delays. The fluid flow model of TCP’s congestion avoidance mode based on delay differential equations supplies the mathematical background for modelling the AQM as a feedback control system and designing different control schemes accordingly. Firstly, the proposed controller design method has been applied to AQM for the case of time invariant time delay and secondly the method has been supported with switching control technique to obtain optimum system performance in the case of time varying time delay. The performance of the designed controllers for both cases has been illustrated by packet level simulations in ns-2.Item Open Access PID and low-order controller design for guaranteed delay margin and pole placement(John Wiley & Sons Ltd., 2021-04-03) Özbay, Hitay; Gündeş, A. N.This article provides a simple low-order controller design method (including PID controllers as special cases) for a class of unstable systems. First, PID controller design is considered for systems with two unstable poles and pole placement and delay margin issues are discussed. Then, a chain of integrators is considered with arbitrary stable dynamics in cascade. For a given desired minimum delay margin for this class of plants, a PID and low-order controller design method is obtained in terms of an inequality constraint on the sum of k of the desired closed-loop poles, where k is number of the integrators in the open-loop transfer function.Item Open Access PID controller synthesis for a class of unstable MIMO plants with I/O delays(Elsevier, 2006-07) Gündeş, A. N.; Özbay, Hitay; Özgüler, A. BülentConditions are presented for closed-loop stabilizability of linear time-invariant (LTI) multi-input, multi-output (MIMO) plants with I/O delays (time delays in the input and/or output channels) using PID (Proportional + Integral + Derivative) controllers. We show that systems with at most two unstable poles can be stabilized by PID controllers provided a small gain condition is satisfied. For systems with only one unstable pole, this condition is equivalent to having sufficiently small delay-unstable pole product. Our method of synthesis of such controllers identify some free parameters that can be used to satisfy further design criteria than stability. Copyright © 2006 IFAC.Item Open Access PID controller synthesis for a class of unstable MIMO plants with I/O delays(Elsevier BV, 2007-01) Gündeş, A. N.; Özbay, Hitay; Özgüler, A. B.Conditions are presented for closed-loop stabilizability of linear time-invariant (LTI) multi-input, multi-output (MIMO) plants with I/O delays (time delays in the input and/or output channels) using PID (Proportional + Integral + Derivative) controllers. We show that systems with at most two unstable poles can be stabilized by PID controllers provided a small gain condition is satisfied. For systems with only one unstable pole, this condition is equivalent to having sufficiently small delay-unstable pole product. Our method of synthesis of such controllers identify some free parameters that can be used to satisfy further design criteria than stability.Item Open Access Resilient PI and PD controller designs for a class of unstable plants with I/O delay(Applied Mathematics Scientific Research Institute, 2007) Özbay, Hitay; Gündeş, A. N.In [8] we obtained stabilizing PID controllers for a class of MIMO unstable plants with time delays in the input and output channels (I/O delays). Using this approach, for plants with one unstable pole, we investigate resilient PI and PD controllers. Specifically, for PD controllers, optimal derivative action gain is determined to maximize the allowable controller gain interval. For PI controllers, optimal proportional gain is determined to maximize a lower bound of the largest allowable integral action gainItem Open Access Resilient PI and PD controllers for a class of unstable MIMO plants with I/O delays(Elsevier, 2006-07) Özbay, Hitay; Gündeş, A. N.Recently (Gündeş et al., 2006) obtained stabilizing PID controllers for a class of MIMO unstable plants with time delays in the input and output channels (I/O delays). Using this approach, for plants with one unstable pole, we investigate resilient PI and PD controllers. Specifically, for PD controllers, optimal derivative action gain is determined to maximize a lower bound of the largest allowable controller gain. For PI controllers, optimal proportional gain is determined to maximize a lower bound of the largest allowable integral action gain. Copyright © 2006 IFAC.