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1 – 10 of over 92000Traffic signal control is one of the oldest application areas of fuzzy sets in transportation. In general, fuzzy control is found to be superior in complex problems with…
Abstract
Traffic signal control is one of the oldest application areas of fuzzy sets in transportation. In general, fuzzy control is found to be superior in complex problems with multi-objective decisions. In traffic signal control, several traffic flows compete for the same time and space, and different priorities are often set to different traffic flows or vehicle groups
The public transport priorities are a very important part of the effective traffic signal control. Normally, the public transport priorities are programmed by using special algorithms, which are tailor-made for each intersection. The experiences have proved that this kind of algorithms can be very effective if some compensation algorithms and the traffic-actuated control mode are used. We believe that using the fuzzified public transport priority algorithms, the measures of effectiveness of traffic signal control can be even better. In this paper, our fuzzy control algorithm of the public transport priorities will be presented.
Evangelia Varoutsa and Robert W. Scapens
The purpose of this paper is to contribute to debates about the relationship between trust and control in the governance of inter-organisational relationships. In particular, the…
Abstract
Purpose
The purpose of this paper is to contribute to debates about the relationship between trust and control in the governance of inter-organisational relationships. In particular, the authors focus on the question of how the relationship between trust and control shifts over time.
Design/methodology/approach
An in-depth case study was conducted in a company operating in the aerospace industry. The authors aim to understand this company’s practices and, at the same time, to use the case study to deepen the knowledge of the complex trust/control nexus. The authors follow the changes in the relationship between trust and control as the company restructured its supply chain, and discuss issues which it had to address in the later phases of the supply chain restructuring.
Findings
The paper illustrates the duality of the trust/control nexus. The authors show how the studied company coped with the complex relationships with its suppliers as collaboration increased. The authors identify particular control mechanisms that the company developed to manage such complexity, such as a supplier strategy and a relationship profile tool.
Research limitations/implications
The paper studies supply chain restructuring and the changing relationship of trust and control over time only from the perspective of the assembler/manufacturer which “owns”/manages the supply chain.
Originality/value
The authors observe a move from inter-personal trust to inter-organisational trust. Furthermore, the authors illustrate how managers can intervene to maintain and stabilise trust and ensure that trust and control do not degrade or escalate beyond desirable levels.
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Hiroki Goto, Ayumu Nishimiya, Hai‐Jiao Guo and Osamu Ichinokura
The purpose of this paper is to propose a new instantaneous torque control method for switched reluctance motor (SR motor) and presents experimental data in electric vehicle (EV…
Abstract
Purpose
The purpose of this paper is to propose a new instantaneous torque control method for switched reluctance motor (SR motor) and presents experimental data in electric vehicle (EV) application.
Design/methodology/approach
The proposed control method uses two kind of techniques: a flux‐based commutation technique prevents the negative phase torque always. On the other hand, a direct phase‐torque distribution technique gives suitable each phase‐torque command under limited DC voltage. These techniques can track motor torque to the command. These control schemes are implemented on a small processor and a field programmable gate array.
Findings
The experimental results of the EV show small torque ripple at low speed on both acceleration and regenerative braking. Changing the parameter of the current stop angle can improve torque ripple at high speed. The proposed method can effectively control motor torque.
Practical implications
The proposed method can reduce torque ripple but the implementation is very simple. The proposed control method can be used for any applications. So, that contributes to expand the application of SR motors.
Originality/value
The proposed control scheme requires just static torque curve obtain by finite element analysis or simple experiments. Complex parameters, such as nonlinear inductance, current to torque profiles, and other heuristics parameters, are not necessary. The proposed control is simple but practical.
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Gerasimos G. Rigatos, Pierluigi Siano, Mohammed S. Al-Numay, Bilal Sari and Masoud Abbaszadeh
The purpose of this article is to treat the nonlinear optimal control problem in EV traction systems which are based on 5-phase induction motors. Five-phase permanent magnet…
Abstract
Purpose
The purpose of this article is to treat the nonlinear optimal control problem in EV traction systems which are based on 5-phase induction motors. Five-phase permanent magnet synchronous motors and five-phase asynchronous induction motors (IMs) are among the types of multiphase motors one can consider for the traction system of electric vehicles (EVs). By distributing the required power in a large number of phases, the power load of each individual phase is reduced. The cumulative rates of power in multiphase machines can be raised without stressing the connected converters. Multiphase motors are also fault tolerant because such machines remain functional even if failures affect certain phases.
Design/methodology/approach
A novel nonlinear optimal control approach has been developed for five-phase IMs. The dynamic model of the five-phase IM undergoes approximate linearization using Taylor series expansion and the computation of the associated Jacobian matrices. The linearization takes place at each sampling instance. For the linearized model of the motor, an H-infinity feedback controller is designed. This controller achieves the solution of the optimal control problem under model uncertainty and disturbances.
Findings
To select the feedback gains of the nonlinear optimal (H-infinity) controller, an algebraic Riccati equation has to be solved repetitively at each time-step of the control method. The global stability properties of the control loop are demonstrated through Lyapunov analysis. Under moderate conditions, the global asymptotic stability properties of the control scheme are proven. The proposed nonlinear optimal control method achieves fast and accurate tracking of reference setpoints under moderate variations of the control inputs.
Research limitations/implications
Comparing to other nonlinear control methods that one could have considered for five-phase IMs, the presented nonlinear optimal (H-infinity) control approach avoids complicated state-space model transformations, is of proven global stability and its use does not require the model of the motor to be brought into a specific state-space form. The nonlinear optimal control method has clear implementation stages and moderate computational effort.
Practical implications
In the transportation sector, there is progressive transition to EVs. The use of five-phase IMs in EVs exhibits specific advantages, by achieving a more balanced distribution of power in the multiple phases of the motor and by providing fault tolerance. The study’s nonlinear optimal control method for five-phase IMs enables high performance for such motors and their efficient use in the traction system of EVs.
Social implications
Nonlinear optimal control for five-phase IMs supports the deployment of their use in EVs. Therefore, it contributes to the net-zero objective that aims at eliminating the emission of harmful exhaust gases coming from human activities. Most known manufacturers of vehicles have shifted to the production of all-electric cars. The study’s findings can optimize the traction system of EVs thus also contributing to the growth of the EV industry.
Originality/value
The proposed nonlinear optimal control method is novel comparing to past attempts for solving the optimal control problem for nonlinear dynamical systems. It uses a novel approach for selecting the linearization points and a new Riccati equation for computing the feedback gains of the controller. The nonlinear optimal control method is applicable to a wider class of dynamical systems than approaches based on the solution of state-dependent Riccati equations.
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Shakib Zohrehvandi, Mohammad Khalilzadeh, Maghsoud Amiri and Shahram Shadrokh
The aim of this research is to propose a buffer sizing and buffer controlling algorithm (BSCA) as a heuristic algorithm for calculating project buffer and feeding buffers as well…
Abstract
Purpose
The aim of this research is to propose a buffer sizing and buffer controlling algorithm (BSCA) as a heuristic algorithm for calculating project buffer and feeding buffers as well as dynamic controlling of buffer consumption in different phases of a wind power plant project in order to achieve a more realistic project duration.
Design/methodology/approach
The BSCA algorithm has two main phases of planning and buffer sizing and construction and buffer consumption. Project buffer and feeding buffers are determined in the planning and buffer sizing phase, and their consumption is controlled in the construction and buffer consumption phase. The heuristic algorithm was coded and run in MATLAB software. The sensitivity analysis was conducted to show the BSCA influence on project implementation. Then, to evaluate the BSCA algorithm, inputs from this project were run through several algorithms recently presented by researchers. Finally, the data of 20 projects previously accomplished by the company were applied to compare the proposed algorithm.
Findings
The results show that BSCA heuristic algorithm outperformed the other algorithms as it shortened the projects' durations. The average project completion time using the BSCA algorithm was reduced by about 15% compared to the previous average project completion time.
Originality/value
The proposed BSCA algorithm determines both the project buffer and feeding buffers and simultaneously controls their consumption in a dynamic way.
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Sandip Mukhopadhyay, Harry Bouwman and Mahadeo Jaiswal
This paper aims to study the critical role played by interorganizational control mechanisms in a mobile ecosystems and how the portfolios of control evolves when the service…
Abstract
Purpose
This paper aims to study the critical role played by interorganizational control mechanisms in a mobile ecosystems and how the portfolios of control evolves when the service moves from an initial idea to a solution that reaches market acceptance. Existing literature provides limited insight into (portfolios of) control mechanisms and how (portfolios of) control dynamically evolve(s) during the various stages of service innovation.
Design/methodology/approach
Based on the Resource Dependency Theory (RDT), this study makes use of multiple cases to identify and validate the key roles of behavioural input and output control mechanisms and how they evolve during different phases of service development.
Findings
Based on multiple cases, it is concluded that a dominant actor uses portfolios of control to acquire complimentary resources, coordinate interdependence between multiple partners and ensure a favourable value distribution for itself. Behavioural control is used in a limited way during the implementation and commercialisation phases, while input control is mostly used during the development phase and output controls are mostly used during implementation and commercialisation phases. The high occurrence of input control in the development phase ensures the lower occurrence of behavioural controls in the implementation phase. This study is very practical in nature, and it provides important insight on how to develop mobile services in collaboration with other organisations.
Research limitations/implications
A limitation of this study is that it is based on two cases in a specific regulatory, cultural and institutional environment, i.e. India, which means that further testing of the propositions, with large-scale samples and within a more international setting, would be required. However, this study does provide some interesting insights that have to be corroborated by additional case studies and a large-scale questionnaire, initially with a focus on India.
Originality/value
From an academic perspective, this study examines organisational controls in a less researched yet dynamic services industry, and is one of the first studies that the researchers have come across that uses RDT to explain the dynamics of control in value networks in the mobile industry. This study is also one of the very few to focus on understanding the objectives of the portfolios of control from the perspective of the structural player. As mentioned earlier, research focussing on integrating governance mechanisms and portfolios of control may provide new insights. From a practical perspective, this study may shed light on how to develop mobile services in collaboration with other organisations.
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Zaatar Makni and Kamel Bouallaga
The starting hesitation of a switched reluctance motor (SRM) is an issue which must be considered in the early motor design. It is mostly handled as a control concern. The…
Abstract
Purpose
The starting hesitation of a switched reluctance motor (SRM) is an issue which must be considered in the early motor design. It is mostly handled as a control concern. The starting procedure of a SRM using a single Hall-effect position sensor is analysed in this paper. This low cost position measurement solution requires a specific control strategy. That has been developed for a three-phase 6/4 SRM. The paper aims to discuss these issues.
Design/methodology/approach
The starting procedure begins with a rotor alignment step intending to bring the rotor to a known position. Afterward, only one phase is supplied on a periodic basis, to drive the rotor in the desired direction and accelerate up to a predefined speed threshold. Thus, the proposed procedure drastically simplifies the control strategy and permits a low cost sensor based control. 2D finite elements simulations are performed to analyse the starting performances in terms of response time and power efficiency. Both electrical and mechanical transients are considered in the simulation model thanks to simplifying assumption which consists in applying a time averaged voltages instead of instantaneous switching. Finally, the entire starting procedure with a one phase supply procedure is tested experimentally.
Findings
A starting procedure of a three-phase SRM is implemented. The control effectiveness is validated by complementary FE calculations and measurements.
Originality/value
The starting hesitation issue of a three-phase SRM is solved with an easy control strategy. During the acceleration phase, only one phase is self-controlled.
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Shaofei Chen, Hongfu Liu, Jing Chen and Lincheng Shen
The purpose of this paper is to plan the penetration trajectory for unmanned aerial vehicle (UAV) in the presence of radar‐guided surface to air missiles (SAMs).
Abstract
Purpose
The purpose of this paper is to plan the penetration trajectory for unmanned aerial vehicle (UAV) in the presence of radar‐guided surface to air missiles (SAMs).
Design/methodology/approach
The penetration trajectory planning problem is modelled based on four aspects of radar tracking features. As penetration just utilizes the low observability of radar cross section (RCS) to satisfy temporal constraints of tracking, the problem is formulated as multi‐phase trajectory planning with detected probability (MTP‐DP). While utilizing both the low observability of RCS and the radial velocity blind area of radar, the problem is formulated as multi‐phase trajectory planning with detected probability and radial velocity (MTP‐DP&RV). The pseudospectral multi‐phase optimal control based trajectory planning algorithm is proposed.
Findings
The results of the examples illustrate that the multi‐phase trajectory planning method can finely utilize the radar tracking features to optimize the comprehensive efficiency of penetration. The pseudospectral multi‐phase optimal control based trajectory planning algorithm could effectively solve the trajectory planning problem.
Originality/value
This paper provides new structured method to plan UAV penetration trajectory for military application and academic study.
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Keywords
Moez Abassi, Omar Khlaief, Oussama Saadaoui, Abdelkader Chaari and Mohamed Boussak
Electric vehicles (EVs) require uninterrupted and safe conditions during operations. Therefore, the diagnostic of power devices and electric motor faults are needed to improve the…
Abstract
Purpose
Electric vehicles (EVs) require uninterrupted and safe conditions during operations. Therefore, the diagnostic of power devices and electric motor faults are needed to improve the availability of the system. Hence, fault-tolerant control (FTC), which combines switch fault detection, hardware redundancy and post-fault control, is used. This paper aims to propose an accurate open-phase fault detection and FTC of a direct torque control permanent magnet synchronous motor electrical vehicles by using discrete Fourier-transform phase method.
Design/methodology/approach
The main idea is to propose detection and identification of open-phase fault (faulty leg) among three phases voltage source invertor (VSI)-fed permanent magnet synchronous motor drives. Once the faulty leg is detected and isolated, a redundant phase leg insertion, shared by a three-phase VSI, is done by using independent bidirectional TRIAC switches to conduct FTC system. This accurate fault detection significantly improves system availability and reliability. The proposed method of open-phase fault detection and identification is based only on stator phase current measurement.
Findings
A novel method is proposed with experimental validation for fault detection, isolation and FTC for a three-phase VSI-fed permanent magnet synchronous motor.
Originality/value
The novel discrete Fourier-transform phase method is proposed to detect an open phase based on the measurement in real time of the instantaneous phase of stator current components in the stationary frame. The experimental implementation is carried out on powerful dSpace DS1104 controller board based on the digital signal processor TMS320F240. The validity of the proposed method has been experimentally verified.
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Mehdi Mosharaf-Dehkordi and Hamid Reza Ghafouri
The purpose of this paper is to present detailed algorithms for simulation of individual and group control of production wells in hydrocarbon reservoirs which are implemented in a…
Abstract
Purpose
The purpose of this paper is to present detailed algorithms for simulation of individual and group control of production wells in hydrocarbon reservoirs which are implemented in a finite volume-based reservoir simulator.
Design/methodology/approach
The algorithm for individual control is described for the multi-lateral multi-connection ones based on the multi-segment model considering cross-flow. Moreover, a general group control algorithm is proposed which can be coupled with any well model that can handle a constraint and returns the flow rates. The performance of oil production process based on the group control criteria is investigated and compared for various cases.
Findings
The proposed algorithm for group control of production wells is a non-optimization iterative scheme converging within a few number of iterations. The numerical results of many computer runs indicate that the nominal power of the production wells, in general, is the best group control criterion for the proposed algorithm. The production well group control with a proper criterion can generally improve the oil recovery process at negligible computational costs when compared with individual control of production wells.
Research/limitations/implications
Although the group control algorithm is implemented for both production and injection wells in the developed simulator, the numerical algorithm is here described only for production wells to provide more details.
Practical/implications
The proposed algorithm can be coupled with any well model providing the fluid flow rates and can be efficiently used for group control of production wells. In addition, the calculated flow rates of the production wells based on the group control algorithm can be used as candidate solutions for the optimizer in the simulation-optimization models. It may reduce the total number of iterations and consequently the computational cost of the simulation-optimization models for the well control problem.
Originality/value
A complete and detailed description of ingredients of an efficient well group control algorithm for the hydrocarbon reservoir is presented. Five group control criteria are extracted from the physical, geometrical and operating conditions of the wells/reservoir. These are the target rate, weighted potential, ultimate rate and introduced nominal power of the production wells. The performance of the group control of production wells with different group control criteria is compared in three different oil production scenarios from a black-oil and highly heterogeneous reservoir.
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