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Mohd Noh Karsiti

Bio: Mohd Noh Karsiti is an academic researcher from Universiti Teknologi Petronas. The author has contributed to research in topics: PID controller & Control theory. The author has an hindex of 13, co-authored 70 publications receiving 500 citations. Previous affiliations of Mohd Noh Karsiti include Petronas & University of California, Irvine.


Papers
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Journal ArticleDOI
TL;DR: In this article, a fractional order set-point weighted PID controller is designed for pH neutralization process to achieve adequate setpoint tracking and effective load regulation through smooth control action.
Abstract: Control of pH processes is highly challenging due to high nonlinearity and sensitivity around the equilibrium point. PID controllers being simple and the most widely used perform poorly with changing set-point and are limited to certain operating regions. Thus, they are inadequate for such applications without upgrading. In this paper, a fractional order set-point weighted PID ( $$\mathrm {SWPI^{\lambda }D^{\mu }}$$ ) controller is designed for pH neutralization process. The objective is to achieve adequate set-point tracking and effective load regulation through smooth control action. The controller parameters are tuned using accelerated particle swarm optimization which uses only global best position to achieve faster convergence. Simulation results show that for both standard and industrial configurations of the proposed approach, better performance in terms of set-point tracking, disturbance rejection and sensitivity to model parameter variation is achieved compared to PID, fractional order PID ( $$\mathrm {PI^{\lambda }D^{\mu }}$$ ) and SWPI-D.

38 citations

Journal ArticleDOI
TL;DR: The proposed two-degree-of-freedom fractional-order PID (2DOF–FOPID) controller for real-time control of pressure process in both parallel and series configurations has the advantages of improving set-point tracking and disturbance rejection performance through smoother control action over the conventional PID.
Abstract: Control of real-time pressure process is quite challenging due to high nonlinearity and sensitivity. PID controllers being the most employed for industrial applications have the potential for control of such processes. This is due to the PID’s advantages of simple structure, ease of tuning and implementation. However, its performance degrades during set-point change and high external disturbances due to high sensitivity and nonlinearity of the pressure plant. Therefore, this paper proposes the two-degree-of-freedom fractional-order PID (2DOF–FOPID) controller for real-time control of pressure process in both parallel and series configurations. Furthermore, the controller parameters are obtained experimentally using Ziegler–Nichols and closed-loop set-point approaches. The controller has the advantages of improving set-point tracking and disturbance rejection performance through smoother control action over the conventional PID. From the real-time experimental results obtained, the proposed approach outperforms PID, fractional-order PID and 2DOF-PID controllers in terms of overshoot and settling time. Hence, the approach has better set-point tracking ability and disturbance rejection capability. Furthermore, the control action of the approach is less affected by undesired oscillations and derivative kick effect thereby extending the life of actuator.

32 citations

Proceedings ArticleDOI
18 Nov 2008
TL;DR: In this article, a starting strategy for a free-piston linear engine-generator (LG) is proposed which utilizes the air-spring quality of the engine cylinders prior to combustion.
Abstract: Starting a free-piston linear engine-generator (LG) involves reciprocating a freely moving piston-magnet-translator assembly between two oppositely placed engine cylinders for combustion to occur. The machine is operated as a brushless linear motor to produce the required motion. However, due to the very large peak compression force during starting, limited current rating of stator coils and insufficient motor force constant, it is not possible to push the translator end to end in a single stroke. A strategy is proposed which utilizes the air-spring quality of the engine cylinders prior to combustion. Energizing the coils with fixed DC voltage and open-loop, rectangular commutation of injected current, sufficiently high motoring force is produced to reciprocate the translator in small amplitudes initially. Due to repeated compression-expansion of the engine cylinders and constant application of motoring force in the direction of natural bouncing motion, the translatorpsilas amplitude and speed is expected to grow - due to mechanical resonance - to finally reach the required parameters for combustion. This work discusses the starting problem and its mechanical aspects for a specific LG configuration, builds a mechanical model of LG and presents simulation results on the viability of the starting strategy using different values of constant-magnitude motoring force.

31 citations

Journal ArticleDOI
TL;DR: A two-level scheduling technique in which heuristic rules are used to determine the job-to-machine routing and the job sequencing and the effectiveness of this strategy on jobs that arrive continuously with prescribed due dates is studied.

30 citations


Cited by
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Book
01 Jan 2005
TL;DR: In this article, the authors propose a formalization theory for the realization of deterministic problems in linear algebra and disctrete-time linear systems based on the Kalman filter.
Abstract: Introduction Part I: Preliminaries Linear Algebra and Preliminaries Disctrete-time Linear Systems Stochastic Processes Kalman Filter Part II: Realization Theory Realization of Deterministic Problems Stochastic Realization Theory I Stochastic Realization Theory II Part III: Subspace Identification Subspace Identification I: ORT Subspace Identification II: CCA Identification of Closed-loop System Appendices Least-squares Method Input Signals for System Identification Overlapping Parametrization Matlab(R) Programs Solutions to Problems

235 citations

Journal ArticleDOI
TL;DR: Increased needle diameter was found to increase peak forces, and conical needles were found to create higher peak forces than beveled needles, and many questions remain open for investigation, especially those concerning the influence of tissue characteristics.

205 citations

Journal ArticleDOI
TL;DR: A rescheduling methodology is proposed that uses a multiobjective performance measures that contain both efficiency and stability measures and is tested on a simulated job shop to determine the impact of the key parameters on the performance measures.

193 citations