Article Per Year (5 Year)
p-Index From 2020 - 2025
0.983
P-Index
This Author published in this journals
All Journal International Journal of Power Electronics and Drive Systems (IJPEDS) TELKOMNIKA (Telecommunication Computing Electronics and Control) Bulletin of Electrical Engineering and Informatics Indonesian Journal of Electrical Engineering and Computer Science
Mohd Ashraf Ahmad
Universiti Malaysia Pahang
Computer Science & IT Control & Systems Engineering Electrical & Electronics Engineering

Published : 7 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 7 Documents
Search

 1 
A piecewise affine PI controller for buck converter generated DC motor Mohd Ikhmil Fadzrizan Mohd Hanif; Mohd Helmi Suid; Mohd Ashraf Ahmad
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 10, No 3: September 2019
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (744.053 KB) | DOI: 10.11591/ijpeds.v10.i3.pp1419-1426

Abstract

This paper presents a new Piecewise Affine Proportional-Integral (PA-PI) controller for angular velocity tracking of a buck converter generated dc motor. A Safe Experimentation Dynamics (SED) algorithm is employed as a data-driven optimization tool to find the optimal PA-PI controller parameters such that the integral square of error and input are reduced. The essential feature of the PA-PI controller is that the parameters of proportional and integral gains are adaptive to the error variations according to the Piecewise Affine (PA) function. Moreover, the proposed PA function is expected to provide better control accuracy than the other existing variable structure PID controller. In order to verify the effectiveness of the PA-PI controller, a widely known buck converter generated dc motor is considered. The performances of the proposed controller are observed in terms of the integral square of error and input, and the responses of the angular velocity and duty ration input. The simulation results verify that the proposed PA-PI controller yields higher control accuracy than the other existing controllers of buck converter generated dc motor.
H-infinity controller with graphical LMI region profile for liquid slosh suppression Mohd Zaidi Mohd Tumari; A. Shamsul Rahimi A. Subki; Mohd Shahrieel Mohd Aras; Mohammad 'Afif Kasno; Mohd Ashraf Ahmad; Mohd Helmi Suid
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 5: October 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i5.11252

Abstract

This paper presents a H-infinity synthesis with pole clustering based on LMI region schemes for liquid slosh control. Using LMI approach, the regional pole placement known as LMI region combined with design objective in H-infinity controller guarantee a fast input tracking capability and very minimal liquid slosh. A graphical profile of the transient response of liquid slosh suppression system with respect to pole placement is very useful in giving more flexibility to the researcher in choosing a specific LMI region. With the purpose to confirm the design of control scheme, a liquid slosh model is considered to represent the lateral slosh movement. Supremacy of the proposed approach is shown by comparing the results with hybrid model-free fuzzy-PID controller with derivative filter. The performance of the control schemes is examined in terms of time response specifications of lateral tank tracking capability and level of liquid slosh reduction.
Grey wolf optimizer for identification of liquid slosh behavior using continuous-time hammerstein model Mohd Ashraf Ahmad; Zulkifli Musa; Mohd Helmi Suid; Mohd Zaidi Mohd Tumari
Bulletin of Electrical Engineering and Informatics Vol 9, No 2: April 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (604.454 KB) | DOI: 10.11591/eei.v9i2.2074

Abstract

This paper presents the identification of liquid slosh plant using the Hammerstein model based on Grey Wolf Optimizer (GWO) method. A remote car that carrying a container of liquid is considered as the liquid slosh experimental rig. In contrast to other research works, this paper consider a piece-wise affine function in the nonlinear function of the Hammerstein model, which is more generalized function. Moreover, a continuous-time transfer function is utilized in the Hammerstein model, which is more suitable to represent a real system. The GWO method is used to tune both coefficients in the nonlinear function and transfer function of the Hammerstein model such that the error between the identified output and the real experimental output is minimized. The effectiveness of the proposed framework is assessed in terms of the convergence curve response, output response, and the stability of the identified model through the bode plot and pole zero map. The results show that the GWO based method is able to produce a Hammerstein model that yields identified output response close to the real experimental slosh output.
Sigmoid PID based adaptive safe experimentation dynamics algorithm of portable duodopa pump for Parkinson’s disease patients Najwa Hidayah Abdul Razak Ramesh; Mohd Riduwan Ghazali; Mohd Ashraf Ahmad
Bulletin of Electrical Engineering and Informatics Vol 10, No 2: April 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v10i2.2542

Abstract

This paper emphasizes on the development of an appropriate closed-loop control strategy for traditional portable duodopa pump (PDP); thereby ensuring an automated drug infusion without wearing off. In particular, a sigmoid proportional integral derivative (SPID) controller is adopted to control the blood plasma level of dopamine. The parameters of SPID controller are tuned using the adaptive safe experimentation dynamics (ASED) algorithm. The efficiency of the suggested SPID-ASED is evaluated by concerning the convergence plot of the cost function, the amount of dopamine in the blood plasma (BP) of the patient, the statistical analysis of cost function, norm of error and norm of input, and time responses specifications. The simulation results show that the proposed SPID-ASED outperforms the standard PID controller in terms of better control accuracy with minimum overshoot and settling time.
Data-based PID control of flexible joint robot using adaptive safe experimentation dynamics algorithm Mohd Ashraf Ahmad; Haszuraidah Ishak; Ahmad Nor Kasruddin Nasir; Normaniha Abd Ghani
Bulletin of Electrical Engineering and Informatics Vol 10, No 1: February 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v10i1.2472

Abstract

This paper proposes the data-based PID controller of flexible joint robot based on adaptive safe experimentation dynamics (ASED) algorithm. The ASED algorithm is an enhanced version of SED algorithm where the updated tuning variable is modified to adapt to the change of the objective function. By adopting the adaptive term to the updated equation of SED, it is expected that the convergence accuracy can be further improved. The effectiveness of the ASED algorithm is verified to tune the PID controller of flexible joint robot. In this flexible joint control problem, two PID controllers are utilized to control both rotary angle tracking and vibration of flexible joint robot. The performance of the proposed data-based PID controller is assessed in terms of trajectory tracking of angular motion, vibration reduction and statistical analysis of the pre-defined control objective function. The simulation results showed that the data-based PID controller based on ASED is able to produce better control accuracy than the conventional SED based method.
Robust super-twisting sliding mode controller for the lateral and longitudinal dynamics of rack steering vehicle Norsharimie Mat Adam; Addie Irawan; Mohd Ashraf Ahmad
Bulletin of Electrical Engineering and Informatics Vol 11, No 4: August 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v11i4.3641

Abstract

Inertia phenomenon in steering vehicle is major factor that allow oversteering incident in which come from the insufficient steering and slip control over the vehicle itself. The efficient and robust control system is required to consider both precision and stability of the vehicle for better manuevering especially in cornering road. Therefore, this research has taken the initiative to contribute a better solution for vehicle control according to the mentioned problem and situation with a proposed robust super-twisting sliding mode control (ST-SMC) by simplified torque on wheel and steering angle input with decoupling lateral and longitudinal errors. This control technique approach to allow coping with the issue by reducing forces and inertia for optimum speed at the cornering period and with the almost precise steering positioning. The dynamic model of rack steering vehicle (RSV) is used as the model plant and the proposed control system is simulated for verification. The results shows that the proposed ST-SMC offers improved performance in terms of speed increase time and vehicle stability that gives impact to the RSV being skidded or collided to any obstacles during cornering period.
Liquid slosh control by implementing model-free PID controller with derivative filter based on PSO Mohd Zaidi Mohd Tumari; Amar Faiz Zainal Abidin; A Shamsul Rahimi A Subki; Ab Wafi Ab Aziz; Muhammad Salihin Saealal; Mohd Ashraf Ahmad
Indonesian Journal of Electrical Engineering and Computer Science Vol 18, No 2: May 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v18.i2.pp750-758

Abstract

Conventionally, the control of liquid slosh system is done based on model-based techniques that challenging to implement practically because of the chaotic motion of fluid in the container. The aim of this article is to develop the tuning technique for model-free PID with derivative filter (PIDF) parameters for liquid slosh suppression system based on particle swarm optimization (PSO). PSO algorithm is responsible to find the optimal values for PIDF parameters based on fitness functions which are Sum Squared Error (SSE) and Sum Absolute Error (SAE) of the cart position and liquid slosh angle response. The modelling of liquid slosh in lateral movement is considered to justify the design of control scheme. The PSO tuning method is compared by heuristic tuning method in order to show the effectiveness of the proposed tuning approach. The performance evaluations of the proposed tuning method are based on the ability of the tank to follow the input in horizontal motion and liquid slosh level reduction in time domain. Based on the simulation results, the suggested tuning method is capable to reduce the liquid slosh level in the same time produces fast input tracking of the tank without precisely model the chaotic motion of the fluid.
Co-Authors A Shamsul Rahimi A Subki A. Shamsul Rahimi A. Subki Ab Wafi Ab Aziz Addie Irawan Ahmad Nor Kasruddin Nasir Amar Faiz Zainal Abidin Haszuraidah Ishak Mohammad 'Afif Kasno Mohd Helmi Suid Mohd Helmi Suid Mohd Ikhmil Fadzrizan Mohd Hanif Mohd Riduwan Ghazali Mohd Shahrieel Mohd Aras Mohd Zaidi Mohd Tumari Muhammad Salihin Saealal Najwa Hidayah Abdul Razak Ramesh Normaniha Abd Ghani Norsharimie Mat Adam Zulkifli Musa