Ahmad Mirabadi - Academia.edu (original) (raw)

Papers by Ahmad Mirabadi

Clean energy, Mar 1, 2024

Transportation research record, Feb 14, 2024

Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Dec 19, 2021

Proper analysis of point machine current signal provides pervasive information of health status o... more Proper analysis of point machine current signal provides pervasive information of health status of their internal components. Point machines are subjected to several failure modes during their operation. “Gearbox,” “ball bearing,” “lead screw,” and “sliding chair” faults are among common mechanical failure modes. In this article, a two-stage prediction innovative process is proposed using Fault Detection based Decision Tree strategy (FDDT) where the healthy and faulty modes are first determined, followed by classifying the types of mechanical faults based on Parallel Neural Network Architecture and Fuzzy System (PNNFS). To differentiate between faulty and healthy point machines, some relevant features are extracted from the motors’ current signals which are used as input data for the proposed FDDT_PNNFS method. Feature selection has been performed using the ReliefF to select the dominant predictors in the point machine. Firstly, the Decision Tree (DT) algorithm is used to obtain a classifier model based on the offline training method for fault detection. The performance of DT is compared with the support vector machine algorithm. In the second stage, faulty data is fed to a bank of Neural Networks, designed in Parallel Neural Network Architecture (PNNA), which is used for identifying the type of failures. Each Neural Network Algorithm (NNA) is responsible for detecting only one type of failure and assessment of the NNA outputs shows the final failure of the point machine. If there is a discrepancy between the outputs of the NNAs, fuzzy logic plays the role of modifier and judges among outputs of NNAs and determines the more probable fault type.

One of the strategies for reduction of energy consumption in railway systems is to execute effici... more One of the strategies for reduction of energy consumption in railway systems is to execute efficient driving by presenting optimized speed profile considering running time, energy consumption and practical constraints. In this paper, by using real route data, an approach based on combination of Genetic and Particle swarm (GA-PSO) algorithms in order to optimize the fuel consumption is provided. The model of train takes into account the length and mass of train, running resistance, tractive effort curves for each notch, signaling system, variations of the motor efficiency with respect to speed and effort ratio, auxiliary equipment consumption and rotary inertia. The route characteristics included in the model are speed limits, gradients, gradient transitions (and its effect along the train) and curves. GA-PSO algorithm combining the benefits of both the original algorithms GA and PSO is validated by formulating the optimization problem. The GA-PSO performance is evaluated by comparin...

1996 IEEE/SICE/RSJ International Conference on Multisensor Fusion and Integration for Intelligent Systems (Cat. No.96TH8242)

ABSTRACT

Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 2011

In this article a fuzzy logic energy management system, for hybrid light weight trains, is design... more In this article a fuzzy logic energy management system, for hybrid light weight trains, is designed and verified. The low axle load, medium-to-low speed, and short stopping distances are from characteristics of light rail vehicles, which make them suitable for implementing hybrid technology, as discussed in this article. In this research work, batteries and flywheels are considered as onboard energy storage devices and a light diesel generator as an onboard energy supply system. Efficient utilization of the mentioned energy sources throughout a cycle of movement from one stopping point to the next and also on the entire route is the aim of the energy management system, investigated in this article. The performance of the fuzzy logic energy management system, is analysed and compared with a standalone diesel and also a hybrid train using a thermostat on/off control strategy.

One of the strategies for reduction of energy consumption in railway systems is to execute effici... more One of the strategies for reduction of energy consumption in railway systems is to execute efficient driving by presenting optimized speed profile considering running time, energy consumption and practical constraints. In this paper, by using real route data, an approach based on combination of Genetic and Particle swarm (GA-PSO) algorithms in order to optimize the fuel consumption is provided. The model of train takes into account the length and mass of train, running resistance, tractive effort curves for each notch, signaling system, variations of the motor efficiency with respect to speed and effort ratio, auxiliary equipment consumption and rotary inertia. The route characteristics included in the model are speed limits, gradients, gradient transitions (and its effect along the train) and curves. GA-PSO algorithm combining the benefits of both the original algorithms GA and PSO is validated by formulating the optimization problem. The GA-PSO performance is evaluated by comparin...

Summary. Due to their important role in providing safe conditions for train movements, railway in... more Summary. Due to their important role in providing safe conditions for train movements, railway interlocking systems are considered as safety critical systems. The reliability, safety and integrity of these systems, relies on reliability and integrity of all stages in their lifecycle including the design, verification, manufacture, test, operation and maintenance. In this paper, the Automatic generation and verification of interlocking control tables, as one of the most important stages in the interlocking design process has been focused on, by the safety critical research group in the School of Railway Engineering, SRE. Three different subsystems including a graphical signalling layout planner, a Control table generator and a Control table verifier, have been introduced. Using NuSMV model checker, the control table verifier analyses the contents of control table besides the safe train movement conditions and checks for any conflicting settings in the table. This includes settings fo...

Transport Problems, 2009

Summary. Due to their important role in providing safe conditions for train movements, railway in... more Summary. Due to their important role in providing safe conditions for train movements, railway interlocking systems are considered as safety critical systems. The reliability, safety and integrity of these systems, relies on reliability and integrity of all stages in their lifecycle including the design, verification, manufacture, test, operation and maintenance. In this paper, the Automatic generation and verification of interlocking control tables, as one of the most important stages in the interlocking design process has been focused on, by the safety critical research group in the School of Railway Engineering, SRE. Three different subsystems including a graphical signalling layout planner, a Control table generator and a Control table verifier, have been introduced. Using NuSMV model checker, the control table verifier analyses the contents of control table besides the safe train movement conditions and checks for any conflicting settings in the table. This includes settings fo...

International Journal of Electrical and Computer Engineering, 2012

This paper deals with condition monitoring of electric switch machine for railway points. Point m... more This paper deals with condition monitoring of electric switch machine for railway points. Point machine, as a complex electro-mechanical device, switch the track between two alternative routes. There has been an increasing interest in railway safety and the optimal management of railway equipments maintenance, e.g. point machine, in order to enhance railway service quality and reduce system failure. This paper explores the development of KolmogorovSmirnov (K-S) test to detect some point failures (external to the machine, slide chairs, fixing, stretchers, etc), while the point machine (inside the machine) is in its proper condition. Time-domain stator Current signatures of normal (healthy) and faulty points are taken by 3 Hall Effect sensors and are analyzed by K-S test. The test is simulated by creating three types of such failures, namely putting a hard stone and a soft stone between stock rail and switch blades as obstacles and also slide chairs’ friction. The test has been applie...

Energy management is one of the key issues in designing different types of hybrid vehicles, inclu... more Energy management is one of the key issues in designing different types of hybrid vehicles, including cars, buses and trains. In this paper a hybrid train is studied in three modes of operation, using three different power sources. In order to keep the energy consumption at an optimum level, it is necessary to consider the characteristics of all the system's elements and also their optimum point of service. A fuzzy logic based energy management system has been designed and implemented. The underlying subject of the fuzzy based energy management system is to optimize the efficiency of internal combustion engine, ICE, considering the other power sources as flywheel and battery. Simulation results have been used to evaluate the performance of the fuzzy logic energy management system.

Due to their important role in providing safe conditions for train movements, railway interlockin... more Due to their important role in providing safe conditions for train movements, railway interlocking systems are considered as safety critical systems. The reliability, safety and integrity of these systems, relies on reliability and integrity of all stages in their lifecycle including the design, verification, manufacture, test, operation and maintenance. In this paper, the Automatic generation and verification of interlocking control tables, as one of the most important stages in the interlocking design process has been focused on, by the safety critical research group in the School of Railway Engineering, SRE. Three different subsystems including a graphical signalling layout planner, a Control table generator and a Control table verifier, have been introduced. Using NuSMV model checker, the control table verifier analyses the contents of control table besides the safe train movement conditions and checks for any conflicting settings in the table. This includes settings for conflic...

Article history: Received: 29.02.2017 Accepted: 25.04.2017 Published:17.06.2017 One of the strate... more Article history: Received: 29.02.2017 Accepted: 25.04.2017 Published:17.06.2017 One of the strategies for reduction of energy consumption in railway systems is to execute efficient driving by presenting optimized speed profile considering running time, energy consumption and practical constraints. In this paper, by using real route data, an approach based on combination of Genetic and Particle swarm (GA-PSO) algorithms in order to optimize the fuel consumption is provided. The model of train takes into account the length and mass of train, running resistance, tractive effort curves for each notch, signaling system, variations of the motor efficiency with respect to speed and effort ratio, auxiliary equipment consumption and rotary inertia. The route characteristics included in the model are speed limits, gradients, gradient transitions (and its effect along the train) and curves. GA-PSO algorithm combining the benefits of both the original algorithms GA and PSO is validated by formu...

─ In this paper, electromagnetic sensor is considered as a train wheel detector, which is one of ... more ─ In this paper, electromagnetic sensor is considered as a train wheel detector, which is one of the most important signalling systems to determine the clearance or occupancy of a track section. The wheel detector is affected by eddy current brakes and this problem has limited its use. In order to improve the wheel detection accuracy and eliminate the eddy current brake effect, the optimal design of sensors is carried out by means of finite element method. Kriging method is utilized to reduce the computational costs. Additionally, genetic algorithm is used as a multiobjective optimization method to find the optimum

Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 2016

In this paper, hybridizing a heavy vehicle is developed. A switcher locomotive is considered for ... more In this paper, hybridizing a heavy vehicle is developed. A switcher locomotive is considered for hybridization. Due to their low operational speed, the switcher locomotives require much lower power when compared to other types of locomotives. Besides, switcher locomotives have higher loss of energy due to their frequent starting and stopping. Hybrid-powered transit vehicles are considered to be excellent replacements for ordinary transit vehicles, since hybrid powered vehicles are equipped with more than one traction power sources. Therefore, a switcher locomotive’s driving cycle is derived from the measured field data and used to calculate and design the hybrid vehicle’s components. A “fuzzy controller” is used to plan a suitable controller for the designed hybrid locomotive. Comparisons show a substantial decrease, both in the fuel consumption and the pollutions of the designed hybrid switcher locomotive versus the conventional diesel-electric locomotives.

UKACC International Conference on Control (CONTROL '98), 1998

ABSTRACT

IET International Conference on Railway Condition Monitoring, 2006

In the first section of this paper after a brief introduction to the fiber optic sensors and thei... more In the first section of this paper after a brief introduction to the fiber optic sensors and their applications in railway industry, the limitations and capabilities of different types including the intensity, phase and wavelength modulated sensors and also their important parameters in these applications have been introduced. In the second section of the paper the simulation result of FBG and FPI sensors for railway application are introduced. For this purpose the rail-wheel interaction, using ANSYS software has been simulated. Finally a sensor for the purpose of measuring the train weight has been modeled and its performance in different conditions is studied.

1996 IEEE/SICE/RSJ International Conference on Multisensor Fusion and Integration for Intelligent Systems (Cat. No.96TH8242), 1996

Advanced automatic train control (ATC) and automatic train protection (ATP) systems form key elem... more Advanced automatic train control (ATC) and automatic train protection (ATP) systems form key elements in the moves to optimise the performance of new generations of trains and railway systems. In these systems, the reliable and accurate measurement of position and speed using on-board systems, plays a vital role in reducing the need for trackside equipment. This is combined with radio transmission systems to report the measured position and speed data to the control centre. New approaches in instrumentation, applying mechatronics technology and engineering and, in particular, sensor fusion, have opened up new paths for achieving better reliability and accuracy in measurement. The authors describe both old and current methods of railway odometry and discuss sensor fusion in general and its application to railway position and speed measurement in particular

Applied Computational Electromagnetics Society Journal

In this paper electromagnetic sensor is considered as a train wheel detector, which is one of the... more In this paper electromagnetic sensor is considered as a train wheel detector, which is one of the most important signalling systems to determine the clearance or occupancy of a track section. The wheel detector is affected by eddy current brakes and this problem has limited its use. In order to improve the wheel detection accuracy and eliminate the eddy current brake effect, the optimal design of sensors is carried out by means of Finite Element Method. Kriging method is utilized to reduce the computational costs. Additionally, genetic algorithm is used as a multi-objective optimization method to find the optimum orientation.

Clean energy, Mar 1, 2024

Transportation research record, Feb 14, 2024

Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Dec 19, 2021

Proper analysis of point machine current signal provides pervasive information of health status o... more Proper analysis of point machine current signal provides pervasive information of health status of their internal components. Point machines are subjected to several failure modes during their operation. “Gearbox,” “ball bearing,” “lead screw,” and “sliding chair” faults are among common mechanical failure modes. In this article, a two-stage prediction innovative process is proposed using Fault Detection based Decision Tree strategy (FDDT) where the healthy and faulty modes are first determined, followed by classifying the types of mechanical faults based on Parallel Neural Network Architecture and Fuzzy System (PNNFS). To differentiate between faulty and healthy point machines, some relevant features are extracted from the motors’ current signals which are used as input data for the proposed FDDT_PNNFS method. Feature selection has been performed using the ReliefF to select the dominant predictors in the point machine. Firstly, the Decision Tree (DT) algorithm is used to obtain a classifier model based on the offline training method for fault detection. The performance of DT is compared with the support vector machine algorithm. In the second stage, faulty data is fed to a bank of Neural Networks, designed in Parallel Neural Network Architecture (PNNA), which is used for identifying the type of failures. Each Neural Network Algorithm (NNA) is responsible for detecting only one type of failure and assessment of the NNA outputs shows the final failure of the point machine. If there is a discrepancy between the outputs of the NNAs, fuzzy logic plays the role of modifier and judges among outputs of NNAs and determines the more probable fault type.

One of the strategies for reduction of energy consumption in railway systems is to execute effici... more One of the strategies for reduction of energy consumption in railway systems is to execute efficient driving by presenting optimized speed profile considering running time, energy consumption and practical constraints. In this paper, by using real route data, an approach based on combination of Genetic and Particle swarm (GA-PSO) algorithms in order to optimize the fuel consumption is provided. The model of train takes into account the length and mass of train, running resistance, tractive effort curves for each notch, signaling system, variations of the motor efficiency with respect to speed and effort ratio, auxiliary equipment consumption and rotary inertia. The route characteristics included in the model are speed limits, gradients, gradient transitions (and its effect along the train) and curves. GA-PSO algorithm combining the benefits of both the original algorithms GA and PSO is validated by formulating the optimization problem. The GA-PSO performance is evaluated by comparin...

1996 IEEE/SICE/RSJ International Conference on Multisensor Fusion and Integration for Intelligent Systems (Cat. No.96TH8242)

ABSTRACT

Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 2011

In this article a fuzzy logic energy management system, for hybrid light weight trains, is design... more In this article a fuzzy logic energy management system, for hybrid light weight trains, is designed and verified. The low axle load, medium-to-low speed, and short stopping distances are from characteristics of light rail vehicles, which make them suitable for implementing hybrid technology, as discussed in this article. In this research work, batteries and flywheels are considered as onboard energy storage devices and a light diesel generator as an onboard energy supply system. Efficient utilization of the mentioned energy sources throughout a cycle of movement from one stopping point to the next and also on the entire route is the aim of the energy management system, investigated in this article. The performance of the fuzzy logic energy management system, is analysed and compared with a standalone diesel and also a hybrid train using a thermostat on/off control strategy.

One of the strategies for reduction of energy consumption in railway systems is to execute effici... more One of the strategies for reduction of energy consumption in railway systems is to execute efficient driving by presenting optimized speed profile considering running time, energy consumption and practical constraints. In this paper, by using real route data, an approach based on combination of Genetic and Particle swarm (GA-PSO) algorithms in order to optimize the fuel consumption is provided. The model of train takes into account the length and mass of train, running resistance, tractive effort curves for each notch, signaling system, variations of the motor efficiency with respect to speed and effort ratio, auxiliary equipment consumption and rotary inertia. The route characteristics included in the model are speed limits, gradients, gradient transitions (and its effect along the train) and curves. GA-PSO algorithm combining the benefits of both the original algorithms GA and PSO is validated by formulating the optimization problem. The GA-PSO performance is evaluated by comparin...

Summary. Due to their important role in providing safe conditions for train movements, railway in... more Summary. Due to their important role in providing safe conditions for train movements, railway interlocking systems are considered as safety critical systems. The reliability, safety and integrity of these systems, relies on reliability and integrity of all stages in their lifecycle including the design, verification, manufacture, test, operation and maintenance. In this paper, the Automatic generation and verification of interlocking control tables, as one of the most important stages in the interlocking design process has been focused on, by the safety critical research group in the School of Railway Engineering, SRE. Three different subsystems including a graphical signalling layout planner, a Control table generator and a Control table verifier, have been introduced. Using NuSMV model checker, the control table verifier analyses the contents of control table besides the safe train movement conditions and checks for any conflicting settings in the table. This includes settings fo...

Transport Problems, 2009

Summary. Due to their important role in providing safe conditions for train movements, railway in... more Summary. Due to their important role in providing safe conditions for train movements, railway interlocking systems are considered as safety critical systems. The reliability, safety and integrity of these systems, relies on reliability and integrity of all stages in their lifecycle including the design, verification, manufacture, test, operation and maintenance. In this paper, the Automatic generation and verification of interlocking control tables, as one of the most important stages in the interlocking design process has been focused on, by the safety critical research group in the School of Railway Engineering, SRE. Three different subsystems including a graphical signalling layout planner, a Control table generator and a Control table verifier, have been introduced. Using NuSMV model checker, the control table verifier analyses the contents of control table besides the safe train movement conditions and checks for any conflicting settings in the table. This includes settings fo...

International Journal of Electrical and Computer Engineering, 2012

This paper deals with condition monitoring of electric switch machine for railway points. Point m... more This paper deals with condition monitoring of electric switch machine for railway points. Point machine, as a complex electro-mechanical device, switch the track between two alternative routes. There has been an increasing interest in railway safety and the optimal management of railway equipments maintenance, e.g. point machine, in order to enhance railway service quality and reduce system failure. This paper explores the development of KolmogorovSmirnov (K-S) test to detect some point failures (external to the machine, slide chairs, fixing, stretchers, etc), while the point machine (inside the machine) is in its proper condition. Time-domain stator Current signatures of normal (healthy) and faulty points are taken by 3 Hall Effect sensors and are analyzed by K-S test. The test is simulated by creating three types of such failures, namely putting a hard stone and a soft stone between stock rail and switch blades as obstacles and also slide chairs’ friction. The test has been applie...

Energy management is one of the key issues in designing different types of hybrid vehicles, inclu... more Energy management is one of the key issues in designing different types of hybrid vehicles, including cars, buses and trains. In this paper a hybrid train is studied in three modes of operation, using three different power sources. In order to keep the energy consumption at an optimum level, it is necessary to consider the characteristics of all the system's elements and also their optimum point of service. A fuzzy logic based energy management system has been designed and implemented. The underlying subject of the fuzzy based energy management system is to optimize the efficiency of internal combustion engine, ICE, considering the other power sources as flywheel and battery. Simulation results have been used to evaluate the performance of the fuzzy logic energy management system.

Due to their important role in providing safe conditions for train movements, railway interlockin... more Due to their important role in providing safe conditions for train movements, railway interlocking systems are considered as safety critical systems. The reliability, safety and integrity of these systems, relies on reliability and integrity of all stages in their lifecycle including the design, verification, manufacture, test, operation and maintenance. In this paper, the Automatic generation and verification of interlocking control tables, as one of the most important stages in the interlocking design process has been focused on, by the safety critical research group in the School of Railway Engineering, SRE. Three different subsystems including a graphical signalling layout planner, a Control table generator and a Control table verifier, have been introduced. Using NuSMV model checker, the control table verifier analyses the contents of control table besides the safe train movement conditions and checks for any conflicting settings in the table. This includes settings for conflic...

Article history: Received: 29.02.2017 Accepted: 25.04.2017 Published:17.06.2017 One of the strate... more Article history: Received: 29.02.2017 Accepted: 25.04.2017 Published:17.06.2017 One of the strategies for reduction of energy consumption in railway systems is to execute efficient driving by presenting optimized speed profile considering running time, energy consumption and practical constraints. In this paper, by using real route data, an approach based on combination of Genetic and Particle swarm (GA-PSO) algorithms in order to optimize the fuel consumption is provided. The model of train takes into account the length and mass of train, running resistance, tractive effort curves for each notch, signaling system, variations of the motor efficiency with respect to speed and effort ratio, auxiliary equipment consumption and rotary inertia. The route characteristics included in the model are speed limits, gradients, gradient transitions (and its effect along the train) and curves. GA-PSO algorithm combining the benefits of both the original algorithms GA and PSO is validated by formu...

─ In this paper, electromagnetic sensor is considered as a train wheel detector, which is one of ... more ─ In this paper, electromagnetic sensor is considered as a train wheel detector, which is one of the most important signalling systems to determine the clearance or occupancy of a track section. The wheel detector is affected by eddy current brakes and this problem has limited its use. In order to improve the wheel detection accuracy and eliminate the eddy current brake effect, the optimal design of sensors is carried out by means of finite element method. Kriging method is utilized to reduce the computational costs. Additionally, genetic algorithm is used as a multiobjective optimization method to find the optimum

Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 2016

In this paper, hybridizing a heavy vehicle is developed. A switcher locomotive is considered for ... more In this paper, hybridizing a heavy vehicle is developed. A switcher locomotive is considered for hybridization. Due to their low operational speed, the switcher locomotives require much lower power when compared to other types of locomotives. Besides, switcher locomotives have higher loss of energy due to their frequent starting and stopping. Hybrid-powered transit vehicles are considered to be excellent replacements for ordinary transit vehicles, since hybrid powered vehicles are equipped with more than one traction power sources. Therefore, a switcher locomotive’s driving cycle is derived from the measured field data and used to calculate and design the hybrid vehicle’s components. A “fuzzy controller” is used to plan a suitable controller for the designed hybrid locomotive. Comparisons show a substantial decrease, both in the fuel consumption and the pollutions of the designed hybrid switcher locomotive versus the conventional diesel-electric locomotives.

UKACC International Conference on Control (CONTROL '98), 1998

ABSTRACT

IET International Conference on Railway Condition Monitoring, 2006

In the first section of this paper after a brief introduction to the fiber optic sensors and thei... more In the first section of this paper after a brief introduction to the fiber optic sensors and their applications in railway industry, the limitations and capabilities of different types including the intensity, phase and wavelength modulated sensors and also their important parameters in these applications have been introduced. In the second section of the paper the simulation result of FBG and FPI sensors for railway application are introduced. For this purpose the rail-wheel interaction, using ANSYS software has been simulated. Finally a sensor for the purpose of measuring the train weight has been modeled and its performance in different conditions is studied.

1996 IEEE/SICE/RSJ International Conference on Multisensor Fusion and Integration for Intelligent Systems (Cat. No.96TH8242), 1996

Advanced automatic train control (ATC) and automatic train protection (ATP) systems form key elem... more Advanced automatic train control (ATC) and automatic train protection (ATP) systems form key elements in the moves to optimise the performance of new generations of trains and railway systems. In these systems, the reliable and accurate measurement of position and speed using on-board systems, plays a vital role in reducing the need for trackside equipment. This is combined with radio transmission systems to report the measured position and speed data to the control centre. New approaches in instrumentation, applying mechatronics technology and engineering and, in particular, sensor fusion, have opened up new paths for achieving better reliability and accuracy in measurement. The authors describe both old and current methods of railway odometry and discuss sensor fusion in general and its application to railway position and speed measurement in particular

Applied Computational Electromagnetics Society Journal

In this paper electromagnetic sensor is considered as a train wheel detector, which is one of the... more In this paper electromagnetic sensor is considered as a train wheel detector, which is one of the most important signalling systems to determine the clearance or occupancy of a track section. The wheel detector is affected by eddy current brakes and this problem has limited its use. In order to improve the wheel detection accuracy and eliminate the eddy current brake effect, the optimal design of sensors is carried out by means of Finite Element Method. Kriging method is utilized to reduce the computational costs. Additionally, genetic algorithm is used as a multi-objective optimization method to find the optimum orientation.