An optimized controller provides consistent performance with high accuracy and precision even in ... more An optimized controller provides consistent performance with high accuracy and precision even in the presence of disturbance forces. Disturbance forces can be a cutting force or friction force or both. Tracking performance of a drive system is critically influenced by the mechanical structure, disturbance forces and work piece mass. Sliding mode controller is designed to compensate disturbance forces especially friction. This paper presents parameter tuning strategies in designing a sliding mode controller in compensating a nonlinear friction behaviour occurred in machine tools application. The main parameter properties of a sliding mode controller are identified and analyzed. The proposed methods are analytically designed and numerically validated by variability index performance. The result analysis is presented by comparison of tracking position errors of linear motion using proposed methods with lower variability index. The result shows that method a with approach b has lower tracking position error and lower variability index, hence a better chattering effect and tracking position error performance.
Accurate roundness or circularity measurement is essential to obtain correct functioning of assem... more Accurate roundness or circularity measurement is essential to obtain correct functioning of assemblies, making roundness an important quality control parameter in manufacturing industry. Since circular motion while milling a circular work piece leads to quadrant glitches, a phenomenon familiar with existence of highly nonlinear friction behavior, roundness measurement was conducted to investigate this surface location error due to feed rate of the moving work table. This paper presents friction behavior on a milling process circular work piece in line resulted from identified surface error location (SLE).
The use of electromyography (EMG) for machine control in a manufacturing environment is challengi... more The use of electromyography (EMG) for machine control in a manufacturing environment is challenging due to the inherent electrical noise, and also because machine operators lack anatomy knowledge of muscle location for electrode placement. In this research, an electrode placement scheme is proposed for this user group. An EMG preamp was constructed to observe EMG patterns in lower forearm when electrodes placed by untrained operators are in less optimal locations. Crosstalk was found to be a major issue when electrodes are placed in imperfect locations. The EMG preamplifier was deliberately constructed with low cost components to simulate the increased floor noise due to electrical interferences f however from the results, the resulting SNR is acceptable. This study shows that in designing a practical EMG input system, electrode placement is a bigger factor compared to electrical interference.
This paper presents the design and analysis of cascade NP/PI position controller for machine tool... more This paper presents the design and analysis of cascade NP/PI position controller for machine tools application. The proposed control structure is an enhancement over the classical cascade P/PI position controller whereby a nonlinear function was designed and embedded onto cascade P/PI controller scheme to add element of robustness to the controller characteristics. The controller design consisted of three steps, namely; design of speed loop, design of position loop, and design of the nonlinear function. Both the speed loop and the position loop were designed based on loop shaping method in frequency domain using gain margin and phase margin as design considerations. The controller gains were confirmed based on results of stability. Three parameters identified for the nonlinear function were rate of variation of nonlinear gain (KO), maximum value of error, (e max ) and sampling frequency, (δ). The controller tracking performances were numerically analysed and validated on an XY feed ...
JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES, 2017
The high demand in tracking performance is crucial in machine tools application. Therefore, the p... more The high demand in tracking performance is crucial in machine tools application. Therefore, the purpose of this paper is to design a Nonlinear PID (NPID) controller for improvement of tracking performance via cutting force. The method was then compared with another method which was conventional PID controller. The configuration included different cutting force disturbances of 1500rpm, 2500rpm and 3500rpm. The parameters were set to 0.4Hz and 0.7Hz frequency for every 10mm and 20mm of amplitude, respectively. The investigation was centred on a comparative study of these two techniques which focused on x-axis of Googol Tech XY ball screw drive system. Results between the designed controllers were validated based on two types of errors; the maximum tracking error and root mean square error. Results showed that the NPID controller recorded better tracking performance compared to PID controller with an error reduction of about 33%. In addition, the results proved that NPID controller is highly practical and suitable to be used for ball screw drive. The controller can be further improved with the implementation of observer such as disturbance observer to compensate the cutting forces.
International Journal of Engineering Science Technologies, 2019
The right leg drive (RLD) is a circuit associated with electrocardiography acquisition circuits. ... more The right leg drive (RLD) is a circuit associated with electrocardiography acquisition circuits. For electromyography (EMG), the RLD circuit is used to a lesser degree. In general, the RLD circuit provides better noise reduction. This study compares the output of the EMG with and without the RLD circuit. The results indicate that with a good filter design, the direct grounding method can match the RLD in terms of noise reduction. As a result, EMG application, the RLD drive can be omitted.
This paper presents the development of the system identification (SI) for the highly nonlinear pi... more This paper presents the development of the system identification (SI) for the highly nonlinear piezoelectric patch actuator. The transfer function is determined by using the nonlinear least square (NLS) method after the direct measurements of input-output data are taken from the actuator that is installed on a well-equipped platform. The results were validated to ensure that the transfer function derived fits well with the experimental output.
Accurate and precise positioning control is critical in designing a positioning servo pneumatic s... more Accurate and precise positioning control is critical in designing a positioning servo pneumatic system. The internal friction force of the pneumatic is one of the disturbances that make it challenging to achieve accurate and precise positioning. Dynamic friction identification and modelling are usually very complex and computationally exhaustive. In addition, pneumatic actuators are nonlinear systems, and applying linear control to the system is a mismatch. This study proposes an enhanced triple nonlinear hyperbolic PID controller with static friction (T-NPID+FSS) feedback module. T-NPID is integrated with nonlinear hyperbolic functions at each PID gain, hence the name. The reference in designing the T-NPID is the Popov stability criterion. Meanwhile, static friction (comparatively more straightforward than dynamic friction) is identified by measuring the actuator's internal friction at various velocities and applying it to the static friction model. T-NPID+FSS is compared to a ...
Life in Belgium for a Malaysian can be a lonely experience (there are not many of us here). Howev... more Life in Belgium for a Malaysian can be a lonely experience (there are not many of us here). However, since the last two years, the students community has grown with the arrival of other Malaysian students and families (although there are all not in Leuven). I would like to extend my sincere appreciation to: Zaini and Ros, Saifullah, Yeong and family, Helmi and Natrah, Am and Nurul, Dr Razak and family, abang Zam, kak Zu and family, and Kelvin and family. Thank you for the friendship and hospitalities. I would also like to thank Akmal and Zura for their warm heart and hospitality towards me and my wife and for all the trips that you have taken us to. Finally, to the Embassy of Malaysia in Brussels, thank you for all the nice receptions and your kind treatment of myself and my wife for all the five years that we are in Belgium. I am also grateful to have known many kind and warm hearted Indonesian friends and families especially Pak Oemar, Mbak Leen and Esti, Gandjar and family, Tegoeh, Ira and family, Singgih, Uly and the kids, Arie and Sarah, and Freddy, Novita and family. This work is made possible with the financial supports of the Ministry of Higher Education Malaysia (SLAB) and the University Technical of Malaysia-Malacca (UTeM). These financial supports are greatly appreciated and indebted. I also wish to express my sincere gratitude towards the International Student Office of K.U.Leuven for the financial support that I have received during the final three months of my stay in Leuven. This financial support has enabled me to complete my study here uninterruptedly and successfully. Finally and most importantly, I wish to express my deepest gratitude to both my parents, Hj. Jamaludin and Hjh Khatijah Bee, my brother Saifullah, and the families in Kedah and Singapore for their prayers, loves, cares, and support. I am greatly indebted to them and may God repay all their deeds and sacrifices. To my wife Zila, there are no words to describe how grateful I am for your company during both the easy and the difficult times of this journey. I salute your patient, dedication, love, and care that have brought happiness and serenity to our life.
A novel CAD/CAM-control system (CADCAMConSys) interpreter functions to communicate data seamlessl... more A novel CAD/CAM-control system (CADCAMConSys) interpreter functions to communicate data seamlessly between CAD/CAM and control system of a machine tool. It was developed using MATLAB graphical user interface that serves as an alternative graphical input interface for position controller. The developed interpreter is capable to interpret CAD/CAM data to be utilized as an alternative reference input for position control scheme designed in MATLAB/Simulink environment. The interpreter aims to further enhance the flexibility and capability of a prototype XYZ milling machine that integrates CAD/CAM data with position control schemes and algorithms designed in MATLAB/Simulink platform. This paper focuses on the analysis of the compatibility of the interpreted CAD/CAM data as the input reference for the controller. This research is expected to produce a control system with versatility in input signal forms.
Fuzzy cognitive map (FCM) is a well-established model of control and decision making based on neu... more Fuzzy cognitive map (FCM) is a well-established model of control and decision making based on neural network and fuzzy logic methodologies. It also serves as a powerful systematic way for analyzing real-life problems where tens of known, partially known, and even unknown factors contribute to complexity of a system. FCM-based inference requires a neural activation function much like other neural network systems. In modeling, in addition to an activation function, FCM involves with weight training to learn about relationships as they exist among contributing factors. Therefore, numerous contributing factors could be analyzed to understand the behaviors of factors within a real-life system and to represent it in form of tangible matrices of weights. This article discusses a new incremental FCM activation function, named cumulative activation, and introduces a new weight training technique using simulated annealing (SA) known as agile FCM. Smooth variation of FCM nodes that is due to cumulative nature of inference results into faster convergence, while a unique minimum cost solution is guaranteed using the SA training module that is entirely expert-independent. A combination of these two techniques suits time-related applications where inclusion of temporal features is necessary. The resulted system is examined through numerical example datasets where the candidate FCM shows sensitivity to dynamic variables over time. A real-life example case is included as well to further support the effectiveness of the developed FCM in modeling of natural and complex systems.
Communications in computer and information science, 2017
This paper presenting an improvement made on material handling system in automotive assembly line... more This paper presenting an improvement made on material handling system in automotive assembly line in order to investigate the changes or influences that affect the assembly line. Some issues from a case study arose where the current transportation took a long time to supply material at assembly line and a risk of damaging the parts is high. Thus, an improvement is done by changing the current transport equipment into AGV and the storage equipment is changed into semi-automatic pick-to-light system. A method of discrete-event simulation using Delmia Quest software is applied. Based on the simulation result, the total production output increase almost 3 folds from the current output factory can produce. It’s concluded that a combined changes give large influences to the manufacturing system. A part of that, Delmia Quest is a useful software to enable decision-making process and improve system effectively without possibility destroying the elements.
Journal of Advanced Manufacturing Technology (JAMT), 2018
Accuracy and precision are the area of interest in machine tools application. It is evaluated via... more Accuracy and precision are the area of interest in machine tools application. It is evaluated via the measurement of tracking performance of the controllers. This study presents a Fast Fourier Transform (FFT) technique that used to evaluate the tracking performance of two controllers, namely NPID Triple Hyperbolic controller and NPID Double Hyperbolic controller for XY Table Ball-screw driven system. The cutting force characteristics are observed by using a FFT technique. Peak amplitude of FFT error on harmonic frequency was observed as a cutting force occurrence on the control system. Two cutting force disturbances that are generated from spindle speed of 1500 rpm and 2500 rpm at frequency of 0.2 Hz of speed of motor were used as a configuration set up to compare the tracking performance between the two controllers. The average error
An optimized controller provides consistent performance with high accuracy and precision even in ... more An optimized controller provides consistent performance with high accuracy and precision even in the presence of disturbance forces. Disturbance forces can be a cutting force or friction force or both. Tracking performance of a drive system is critically influenced by the mechanical structure, disturbance forces and work piece mass. Sliding mode controller is designed to compensate disturbance forces especially friction. This paper presents parameter tuning strategies in designing a sliding mode controller in compensating a nonlinear friction behaviour occurred in machine tools application. The main parameter properties of a sliding mode controller are identified and analyzed. The proposed methods are analytically designed and numerically validated by variability index performance. The result analysis is presented by comparison of tracking position errors of linear motion using proposed methods with lower variability index. The result shows that method a with approach b has lower tracking position error and lower variability index, hence a better chattering effect and tracking position error performance.
Accurate roundness or circularity measurement is essential to obtain correct functioning of assem... more Accurate roundness or circularity measurement is essential to obtain correct functioning of assemblies, making roundness an important quality control parameter in manufacturing industry. Since circular motion while milling a circular work piece leads to quadrant glitches, a phenomenon familiar with existence of highly nonlinear friction behavior, roundness measurement was conducted to investigate this surface location error due to feed rate of the moving work table. This paper presents friction behavior on a milling process circular work piece in line resulted from identified surface error location (SLE).
The use of electromyography (EMG) for machine control in a manufacturing environment is challengi... more The use of electromyography (EMG) for machine control in a manufacturing environment is challenging due to the inherent electrical noise, and also because machine operators lack anatomy knowledge of muscle location for electrode placement. In this research, an electrode placement scheme is proposed for this user group. An EMG preamp was constructed to observe EMG patterns in lower forearm when electrodes placed by untrained operators are in less optimal locations. Crosstalk was found to be a major issue when electrodes are placed in imperfect locations. The EMG preamplifier was deliberately constructed with low cost components to simulate the increased floor noise due to electrical interferences f however from the results, the resulting SNR is acceptable. This study shows that in designing a practical EMG input system, electrode placement is a bigger factor compared to electrical interference.
This paper presents the design and analysis of cascade NP/PI position controller for machine tool... more This paper presents the design and analysis of cascade NP/PI position controller for machine tools application. The proposed control structure is an enhancement over the classical cascade P/PI position controller whereby a nonlinear function was designed and embedded onto cascade P/PI controller scheme to add element of robustness to the controller characteristics. The controller design consisted of three steps, namely; design of speed loop, design of position loop, and design of the nonlinear function. Both the speed loop and the position loop were designed based on loop shaping method in frequency domain using gain margin and phase margin as design considerations. The controller gains were confirmed based on results of stability. Three parameters identified for the nonlinear function were rate of variation of nonlinear gain (KO), maximum value of error, (e max ) and sampling frequency, (δ). The controller tracking performances were numerically analysed and validated on an XY feed ...
JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES, 2017
The high demand in tracking performance is crucial in machine tools application. Therefore, the p... more The high demand in tracking performance is crucial in machine tools application. Therefore, the purpose of this paper is to design a Nonlinear PID (NPID) controller for improvement of tracking performance via cutting force. The method was then compared with another method which was conventional PID controller. The configuration included different cutting force disturbances of 1500rpm, 2500rpm and 3500rpm. The parameters were set to 0.4Hz and 0.7Hz frequency for every 10mm and 20mm of amplitude, respectively. The investigation was centred on a comparative study of these two techniques which focused on x-axis of Googol Tech XY ball screw drive system. Results between the designed controllers were validated based on two types of errors; the maximum tracking error and root mean square error. Results showed that the NPID controller recorded better tracking performance compared to PID controller with an error reduction of about 33%. In addition, the results proved that NPID controller is highly practical and suitable to be used for ball screw drive. The controller can be further improved with the implementation of observer such as disturbance observer to compensate the cutting forces.
International Journal of Engineering Science Technologies, 2019
The right leg drive (RLD) is a circuit associated with electrocardiography acquisition circuits. ... more The right leg drive (RLD) is a circuit associated with electrocardiography acquisition circuits. For electromyography (EMG), the RLD circuit is used to a lesser degree. In general, the RLD circuit provides better noise reduction. This study compares the output of the EMG with and without the RLD circuit. The results indicate that with a good filter design, the direct grounding method can match the RLD in terms of noise reduction. As a result, EMG application, the RLD drive can be omitted.
This paper presents the development of the system identification (SI) for the highly nonlinear pi... more This paper presents the development of the system identification (SI) for the highly nonlinear piezoelectric patch actuator. The transfer function is determined by using the nonlinear least square (NLS) method after the direct measurements of input-output data are taken from the actuator that is installed on a well-equipped platform. The results were validated to ensure that the transfer function derived fits well with the experimental output.
Accurate and precise positioning control is critical in designing a positioning servo pneumatic s... more Accurate and precise positioning control is critical in designing a positioning servo pneumatic system. The internal friction force of the pneumatic is one of the disturbances that make it challenging to achieve accurate and precise positioning. Dynamic friction identification and modelling are usually very complex and computationally exhaustive. In addition, pneumatic actuators are nonlinear systems, and applying linear control to the system is a mismatch. This study proposes an enhanced triple nonlinear hyperbolic PID controller with static friction (T-NPID+FSS) feedback module. T-NPID is integrated with nonlinear hyperbolic functions at each PID gain, hence the name. The reference in designing the T-NPID is the Popov stability criterion. Meanwhile, static friction (comparatively more straightforward than dynamic friction) is identified by measuring the actuator's internal friction at various velocities and applying it to the static friction model. T-NPID+FSS is compared to a ...
Life in Belgium for a Malaysian can be a lonely experience (there are not many of us here). Howev... more Life in Belgium for a Malaysian can be a lonely experience (there are not many of us here). However, since the last two years, the students community has grown with the arrival of other Malaysian students and families (although there are all not in Leuven). I would like to extend my sincere appreciation to: Zaini and Ros, Saifullah, Yeong and family, Helmi and Natrah, Am and Nurul, Dr Razak and family, abang Zam, kak Zu and family, and Kelvin and family. Thank you for the friendship and hospitalities. I would also like to thank Akmal and Zura for their warm heart and hospitality towards me and my wife and for all the trips that you have taken us to. Finally, to the Embassy of Malaysia in Brussels, thank you for all the nice receptions and your kind treatment of myself and my wife for all the five years that we are in Belgium. I am also grateful to have known many kind and warm hearted Indonesian friends and families especially Pak Oemar, Mbak Leen and Esti, Gandjar and family, Tegoeh, Ira and family, Singgih, Uly and the kids, Arie and Sarah, and Freddy, Novita and family. This work is made possible with the financial supports of the Ministry of Higher Education Malaysia (SLAB) and the University Technical of Malaysia-Malacca (UTeM). These financial supports are greatly appreciated and indebted. I also wish to express my sincere gratitude towards the International Student Office of K.U.Leuven for the financial support that I have received during the final three months of my stay in Leuven. This financial support has enabled me to complete my study here uninterruptedly and successfully. Finally and most importantly, I wish to express my deepest gratitude to both my parents, Hj. Jamaludin and Hjh Khatijah Bee, my brother Saifullah, and the families in Kedah and Singapore for their prayers, loves, cares, and support. I am greatly indebted to them and may God repay all their deeds and sacrifices. To my wife Zila, there are no words to describe how grateful I am for your company during both the easy and the difficult times of this journey. I salute your patient, dedication, love, and care that have brought happiness and serenity to our life.
A novel CAD/CAM-control system (CADCAMConSys) interpreter functions to communicate data seamlessl... more A novel CAD/CAM-control system (CADCAMConSys) interpreter functions to communicate data seamlessly between CAD/CAM and control system of a machine tool. It was developed using MATLAB graphical user interface that serves as an alternative graphical input interface for position controller. The developed interpreter is capable to interpret CAD/CAM data to be utilized as an alternative reference input for position control scheme designed in MATLAB/Simulink environment. The interpreter aims to further enhance the flexibility and capability of a prototype XYZ milling machine that integrates CAD/CAM data with position control schemes and algorithms designed in MATLAB/Simulink platform. This paper focuses on the analysis of the compatibility of the interpreted CAD/CAM data as the input reference for the controller. This research is expected to produce a control system with versatility in input signal forms.
Fuzzy cognitive map (FCM) is a well-established model of control and decision making based on neu... more Fuzzy cognitive map (FCM) is a well-established model of control and decision making based on neural network and fuzzy logic methodologies. It also serves as a powerful systematic way for analyzing real-life problems where tens of known, partially known, and even unknown factors contribute to complexity of a system. FCM-based inference requires a neural activation function much like other neural network systems. In modeling, in addition to an activation function, FCM involves with weight training to learn about relationships as they exist among contributing factors. Therefore, numerous contributing factors could be analyzed to understand the behaviors of factors within a real-life system and to represent it in form of tangible matrices of weights. This article discusses a new incremental FCM activation function, named cumulative activation, and introduces a new weight training technique using simulated annealing (SA) known as agile FCM. Smooth variation of FCM nodes that is due to cumulative nature of inference results into faster convergence, while a unique minimum cost solution is guaranteed using the SA training module that is entirely expert-independent. A combination of these two techniques suits time-related applications where inclusion of temporal features is necessary. The resulted system is examined through numerical example datasets where the candidate FCM shows sensitivity to dynamic variables over time. A real-life example case is included as well to further support the effectiveness of the developed FCM in modeling of natural and complex systems.
Communications in computer and information science, 2017
This paper presenting an improvement made on material handling system in automotive assembly line... more This paper presenting an improvement made on material handling system in automotive assembly line in order to investigate the changes or influences that affect the assembly line. Some issues from a case study arose where the current transportation took a long time to supply material at assembly line and a risk of damaging the parts is high. Thus, an improvement is done by changing the current transport equipment into AGV and the storage equipment is changed into semi-automatic pick-to-light system. A method of discrete-event simulation using Delmia Quest software is applied. Based on the simulation result, the total production output increase almost 3 folds from the current output factory can produce. It’s concluded that a combined changes give large influences to the manufacturing system. A part of that, Delmia Quest is a useful software to enable decision-making process and improve system effectively without possibility destroying the elements.
Journal of Advanced Manufacturing Technology (JAMT), 2018
Accuracy and precision are the area of interest in machine tools application. It is evaluated via... more Accuracy and precision are the area of interest in machine tools application. It is evaluated via the measurement of tracking performance of the controllers. This study presents a Fast Fourier Transform (FFT) technique that used to evaluate the tracking performance of two controllers, namely NPID Triple Hyperbolic controller and NPID Double Hyperbolic controller for XY Table Ball-screw driven system. The cutting force characteristics are observed by using a FFT technique. Peak amplitude of FFT error on harmonic frequency was observed as a cutting force occurrence on the control system. Two cutting force disturbances that are generated from spindle speed of 1500 rpm and 2500 rpm at frequency of 0.2 Hz of speed of motor were used as a configuration set up to compare the tracking performance between the two controllers. The average error
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