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Control Engineering Practice 
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ISSN (Print) 0967-0661
Published by Elsevier
[2556 journals]
[11 followers] Follow Subscription journalISSN (Print) 0967-0661
Published by Elsevier
[2556 journals]- Absolute stability analysis of sampled-data scaled bilateral teleoperation systems
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): Ali Jazayeri , Mahdi Tavakoli
Stability of a bilateral teleoperation system may be jeopardized by controller discretization, which has been shown to involve energy leaks. This paper proposes a novel approach to analyzing the absolute stability of sampled-data bilateral teleoperation systems consisting of discrete-time controllers and continuous-time master, slave, operator, and environment. The proposed stability analysis permits scaling and delay in the master and the slave positions and forces. The absolute stability conditions reported here impose bounds on the gains of the discrete-time controller, the damping terms of the master and the slave, and the sampling time. A design-related application of these results is in proper selection of various control parameters and the sampling rate for stable teleoperation under discrete-time control. To explore the trade-off between the control gains and the sampling time, it is studied that how large sampling times, which require low control gains for maintaining stability, can lead to unacceptable teleoperation transparency and human task performance in a teleoperated switching task. This shows that the effect of sampling time must be taken into account because neglecting it (as in the absolute stability literature) undermines both stability and transparency of teleoperation. The resulting absolute stability condition has been verified via experiments with two Phantom Omni robots.
PubDate: 2013-05-19T00:30:37Z
- Abstract: Publication date: August 2013
- Adaptive feed-forward compensation for hybrid control with acceleration time waveform replication on electro-hydraulic shaking table
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): Shen Gang , Zhu Zhen-Cai , Zhang Lei , Tang Yu , Yang Chi-fu , Zhao Jin-song , Liu Guang-da , Han Jun-Wei
This article presents a high fidelity acceleration time waveform replication (TWR) on an electro-hydraulic shaking table (EHST) using the hybrid control combined with an offline feed-forward compensator and an online adaptive inverse control (AIC). This study applies the acceleration and velocity feedback to improve the steady performance of the EHST, and employs the system inverse transfer function (ITF) of the acceleration closed-loop system to extend the frequency bandwidth and a modeling error compensator to improve the dynamic characteristics. Moreover, the investigation utilizes a Zero Phase Error Tracking Controller to improve the accuracy of the designed ITF. The proposed hybrid controller also utilizes an online AIC for a high fidelity TWR after that the dynamic characteristics has been improved by the feedback and feed-forward controllers. Thus, the proposed hybrid control strategy combines the merits of the offline feed-forward compensation and online AIC. Performance analysis and comparison of the experimental results demonstrate that better replication accuracy with the proposed hybrid control can be achieved in experiments on an actual EHST.
PubDate: 2013-05-19T00:30:37Z
- Abstract: Publication date: August 2013
- Integrated design of the feedback controller and topography estimator for atomic force microscopy
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): S. Kuiper , P.M.J. Van den Hof , G. Schitter
In atomic force microscopy (AFM) the force between the measurement tip and the sample is controlled in a feedback loop to prevent damage of the tip and sample during imaging, and to convert the measurement of the tip–sample force into an estimate of the sample topography. Dynamical uncertainties of the system limit the achievable control bandwidth and the accuracy of the topography estimation. This paper presents an integrated approach to design a feedback controller and topography estimator, taking into account the dynamical uncertainties of the system. The proposed methodology is experimentally demonstrated on a commercial AFM system, showing a direct trade-off between the control bandwidth and the accuracy of the topography estimation.
PubDate: 2013-05-19T00:30:37Z
- Abstract: Publication date: August 2013
- Gain scheduling adaptive control applied to a particular mixer-settler equipment
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): L.S.L. Fernandes , F.C. Moraes Filho , J.B.A. Paulo , J.A. Oliveira
The mixer-settler based on phase inversion (MSBPI) is a system used for treatment of wastewaters in order to reduce the content of oils and greases from wastewaters produced in oil industry. Its operation principle combines mixing, extraction and separation by decantation in a unique process. In particular, for control purpose, the level of the interface between organic solvent and water, in the separation section, is a critical variable to guarantee performance and security during operation of the MSBPI. In this work, an image-based detector to monitor the organic solvent–water interface level is proposed and a feedback control loop for the process is presented. Initially, a conventional controller (PID) was implemented and, subsequently, a strategy of gain scheduling adaptive control was developed in order to improve the process response in closed-loop. The experimental results showed that the adaptive control presented an efficient performance, even when disturbances of significant magnitude were applied to the process.
PubDate: 2013-05-19T00:30:37Z
- Abstract: Publication date: August 2013
- Spark ignition engine control strategies for minimising cold start fuel consumption under cumulative tailpipe emissions constraints
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): D.I. Andrianov , C. Manzie , M.J. Brear
This paper proposes a methodology for minimising the fuel consumption of a gasoline fuelled vehicle during cold starting. It first takes a validated dynamic model of an engine and its aftertreatment reported in a previous study (Andrianov, Brear, & Manzie, 2012) to identify optimised engine control strategies using iterative dynamic programming. This is demonstrated on a family of optimisation problems, in which fuel consumption is minimised subject to different tailpipe emissions constraints and exhaust system designs. Potential benefits of using multi-parameter optimisation, involving spark timing, air–fuel ratio and cam timing, are quantified. Single switching control policies are then proposed that perform close to the optimised strategies obtained from the dynamic programming but which require far less computational effort.
PubDate: 2013-05-15T00:30:32Z
- Abstract: Publication date: August 2013
- Operational predictive optimal control of Barcelona water transport network
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): J. Pascual , J. Romera , V. Puig , G. Cembrano , R. Creus , M. Minoves
This paper describes the application of model-based predictive control (MPC) techniques to the supervisory flow management in large-scale drinking water networks including a telemetry/telecontrol system. MPC is used to generate flow control strategies (set-points for the regulatory controllers) from the sources to the consumer areas to meet future demands, optimizing performance indexes associated to operational goals such as economic cost, safety storage volumes in the network and smoothness of the flow control actions. The designed management strategies are applied to a model of a real case study: the drinking water transport network of Barcelona (Spain).
PubDate: 2013-05-15T00:30:32Z
- Abstract: Publication date: August 2013
- Model-driven engineering of process control software – beyond device-centric abstractions
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): Tomaž Lukman , Giovanni Godena , Jeff Gray , Marjan Heriǒko , Stanko Strmǒnik
This paper presents a new, two-level, model-driven engineering approach to industrial process control software. The first level (infrastructure engineering) is concerned with the following: the definition of the development process and guidelines, the definition of a domain-specific modeling language, the specification of the model transformations, and the development of a tool suite. This tool suite enables modeling of the process control software and the automatic code generation for programmable logic controllers. In the second level (application engineering), the process control software is engineered using the results of the infrastructure level. The approach is demonstrated on excerpts from an industrial project.
PubDate: 2013-05-15T00:30:32Z
- Abstract: Publication date: August 2013
- Adaptive configuration control of multiple UAVs
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): Zachary T. Dydek , Anuradha M. Annaswamy , Eugene Lavretsky
Several missions including surveillance, exploration, search-and-track, and lifting of heavy loads are best accomplished by multiple unmanned aerial vehicles (UAVs). Another important advantage to utilizing multiple vehicles is a reduction in the risk to successful completion of a mission due to the loss of a single vehicle. This increased robustness can lead to a commensurate decrease in vehicle specifications and cost, further improving the argument for swarm operations. This paper describes the development of an adaptive configuration controller for multiple vehicles executing a cooperative task in the presence of parametric uncertainty. A novel adaptive outer-loop controller that uses both local and global information is presented.
PubDate: 2013-05-15T00:30:32Z
- Abstract: Publication date: August 2013
- An acceleration measurements-based approach for helicopter nonlinear flight control using Incremental Nonlinear Dynamic Inversion
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): P. Simplício , M.D. Pavel , E. van Kampen , Q.P. Chu
Due to the inherent instabilities and nonlinearities of rotorcraft dynamics, its changing properties during flight and the engineering difficulties to predict its aerodynamics with high levels of fidelity, helicopter flight control requires the application of special strategies. These strategies must allow to cope with the nonlinearities of the system and assure robustness in the presence of inaccuracies and changes in configuration. In this paper, a novel approach based on an Incremental Nonlinear Dynamic Inversion is applied to simplify the design of helicopter flight controllers. With this strategy, by employing the feedback of acceleration measurements to avoid the need for information relative to any aerodynamic change, the control system does not need any model data that depends exclusively on its states, thus enhancing its robustness to model uncertainties. The overall control system is tested by simulating two tasks with distinct agility levels as described in the ADS-33 helicopter handling qualities standard. The analysis shows that the controller provides an efficient tracking of the commanded references. Furthermore, with the robustness properties verified within the range of inaccuracies expected to be found in reality, this novel method seems to be eligible for a potential practical implementation to helicopter vehicles.
PubDate: 2013-05-15T00:30:32Z
- Abstract: Publication date: August 2013
- A unified discussion on signal filtering in PID control
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): Tore Hägglund
The major input signals entering the PID controller are; the set point, the process output, and measurable load disturbances. By feeding these signals through suitable filters, the properties of the feedback loop can be improved significantly. The goal of this paper is to provide a unified discussion about these filters. The paper treats set-point handling, feedforward from load disturbances, TITO (two input two output) control, noise filtering, and process dynamics compensation. An industrial case from the steel industry is also presented.
PubDate: 2013-05-15T00:30:32Z
- Abstract: Publication date: August 2013
- An observer looks at the cell temperature in automotive battery packs
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): Maxime Debert , Guillaume Colin , Gérard Bloch , Yann Chamaillard
The internal temperature of Li-ion batteries for electric or hybrid vehicles is an important factor influencing their ageing. Generally not measured, it can be reconstructed from an external measurement and a model. This paper presents the simplified modelling of heat transfers in a battery module, leading to a Linear Parameter-Varying (LPV) model. Then, a polytopic observer is proposed to estimate the cell temperature and internal resistance, ensuring a tradeoff between the convergence speed and the noise of the estimated states. Experimental results show the good quality of the estimation and the diagnosis potential offered by internal resistance reconstruction.
PubDate: 2013-05-15T00:30:32Z
- Abstract: Publication date: August 2013
- A passivity-based controller for coordination of converters in a fuel cell system
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): M. Hilairet , M. Ghanes , O. Béthoux , V. Tanasa , J-P. Barbot , D. Normand-Cyrot
The problem of converters coordination of a fuel cell system involving a hydrogen fuel cell with super-capacitors for applications with high instantaneous dynamic power is addressed in this paper. The problem is solved by using a non-linear controller based on passivity. The controller design is based on the interconnection and damping assignment approach, where the proof of the local system stability of the whole closed-loop system is shown. Simulation and experimental results on a reduced scale system prove the feasibility of the proposed approach for a real electrical vehicle.
PubDate: 2013-05-15T00:30:32Z
- Abstract: Publication date: August 2013
- Second-order sliding mode observer for multiple kinetic rates estimation in bioprocesses
- Abstract: Publication date: Available online 12 May 2013
Source:Control Engineering Practice
Author(s): Sebastián Nuñez , Hernán De Battista , Fabricio Garelli , Alejandro Vignoni , Jesús Picó
Specific kinetic rates are key variables regarding metabolic activity in bioprocesses. They are non-linear functions of concentrations and operating conditions and therefore of difficult access for process control. In this paper, a multiple kinetic rates observer based on second-order sliding mode ideas is proposed. The main difference with other proposals is that smooth estimates are achieved in finite-time without adding additional dynamics. The resulting estimator is robust against uncertainty in the model of the estimated variables. Experimental results from continuous fermentation of S. cerevisiae are presented, where microbial specific growth rate and net ethanol production rate are estimated.
PubDate: 2013-05-15T00:30:32Z
- Abstract: Publication date: Available online 12 May 2013
- A nonlinear hybrid controller for swinging-up and stabilizing the Furuta pendulum
- Abstract: Publication date: August 2013
Source:Control Engineering Practice, Volume 21, Issue 8
Author(s): J. Aracil , J.Á. Acosta , F. Gordillo
The conventional switching strategy for solving the inverted pendulum control problem is based on two steps: swinging-up and stabilization. In this note, first, a new strategy for swinging the Furuta pendulum up towards the desired upright position is designed using the Speed-Gradient method, which uses only directly measured coordinates. Then, a nonlinear controller, based on the Forwarding approach, stabilizes the upright position. As a new contribution the latter leads to a nonlinear stabilizer around the upright position, whose Lyapunov function yields a larger size estimation of the domain of attraction than the one obtained with the traditional linear approach. This estimation allows us to use it in a global switching strategy in the practical implementation and guarantees almost-global asymptotic stability of the equilibrium. Successful experimental results are reported with the available laboratory Furuta pendulum.
PubDate: 2013-05-07T00:30:39Z
- Abstract: Publication date: August 2013
- OBC ‐ Autogenerate contents and barcode
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
PubDate: 2013-05-03T00:31:10Z
- Abstract: Publication date: July 2013
- IFC ‐ Editorial Board / Funding body / agreements policies
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
PubDate: 2013-05-03T00:31:10Z
- Abstract: Publication date: July 2013
- Control of diesel engine dual-loop EGR air-path systems by a singular perturbation method
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
Author(s): Fengjun Yan , Junmin Wang
This paper presents a singular perturbation based method for controlling the dual-loop exhaust gas recirculation (DL-EGR) air-path systems on advanced diesel engines. A DL-EGR air-path system, consisting of a high-pressure loop EGR (HPL-EGR) and a low-pressure loop EGR (LPL-EGR), has significantly different time-scales (fast and slow) due to the inherent difference in the HPL-EGR’s and LPL-EGR’s corresponding control volumes. Such a feature of the DL-EGR systems makes the cooperative control of intake manifold gas conditions challenging. By considering the DL-EGR air-path system as a singularly perturbed system, a composite control law was devised to achieve systematic control of the air-path conditions including gas pressure, temperature, and oxygen fraction in the intake manifold. The effectiveness of the control method is experimentally evaluated on a medium-duty diesel engine.
PubDate: 2013-04-25T00:30:31Z
- Abstract: Publication date: July 2013
- Observer-based backstepping control of linear stepping motor
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
Author(s): Chen-Sheng Ting , Yong-Nong Chang
This paper introduces an observer-based control approach for linear stepping motor (LSM) drive systems. The nonlinear motor dynamics is addressed in the backstepping control framework. Based on this model, a systematic analysis and design algorithm is developed to deal with stabilization and trajectory tracking of linear stepping motor systems. Moreover, to broaden the application range, the backstepping control method is extended to the output feedback control scheme. With simply measuring mover position, an observer-based backstepping controller is constructed to ensure satisfactory performance. In contrast to the conventional current regulated control strategy, this investigation considers a voltage-controlled pulse-width modulation (PWM) strategy with a complete theoretic exploration. The numerical simulations and experimental results illustrate the correctness and effectiveness of proposed approach.
PubDate: 2013-04-21T00:30:34Z
- Abstract: Publication date: July 2013
- Lyapunov-based switched extremum seeking for photovoltaic power maximization
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
Author(s): Scott J. Moura , Yiyao A. Chang
This paper presents a practical variation of extremum seeking (ES) that guarantees asymptotic convergence through a Lyapunov-based switching scheme (Lyap-ES). Traditional ES methods enter a limit cycle around the optimum. Lyap-ES converges to the optimum by exponentially decaying the perturbation signal once the system enters a neighborhood around the extremum. As a case study, we consider maximum power point tracking (MPPT) for photovoltaics. Simulation results demonstrate how Lyap-ES is self-optimizing in the presence of varying environmental conditions and produces greater energy conversion efficiencies than traditional MPPT methods. Experimentally measured environmental data is applied to investigate performance under realistic operating scenarios.
PubDate: 2013-04-21T00:30:34Z
- Abstract: Publication date: July 2013
- RBF neural network inferential sensor for process emission monitoring
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
Author(s): Surajdeen A. Iliyas , Moustafa. Elshafei , Mohamed A. Habib , Ahmed A. Adeniran
Inferential sensing, or soft sensing, gained popularity in recent years as an alternative to continuous emission monitoring systems because of its simplicity, reliability, and cost effectiveness as compared to analogous hardware sensors. In this paper we address the problem of NO x emission using a model of furnace of an industrial boiler, and propose a neural network structure for high performance prediction of NO x as well as O2. The studied boiler is 160MW, gas fired with natural gas, water-tube boiler, having two vertically aligned burners. The boiler model is a 3D problem that involves turbulence, combustion, radiation in addition to NO x modeling. The 3D computational fluid dynamic model is developed using Fluent simulation package. The model provides calculations of the 3D temperature distribution as well as the rate of formation of the NO x pollutant, enabling a better understanding on how and where NO x are produced. The boiler was simulated under various operating conditions. The generated data is then used for initial development and assessment of neural network soft sensors for emission prediction based on the conventional process variable measurements. The performance of the proposed soft sensor is then evaluated using actual data from an industrial boiler. The developed soft sensor achieves comparable accuracy to the continuous emission monitor analyzer, however, with substantial reduction in the cost of equipment and maintenance.
PubDate: 2013-04-21T00:30:34Z
- Abstract: Publication date: July 2013
- Experimental-based feedforward control for a DoD inkjet printhead
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
Author(s): M. Ezzeldin , P.P.J. van den Bosch , S. Weiland
Markets demand continuously for higher quality, higher speed, and more energy-efficient professional printers. Drop-on-Demand (DoD) inkjet printing is considered as one of the most promising printing technologies. It offers many advantages including high speed, quiet operation, and compatibility with a variety of printing media. Nowadays, it has been used as low-cost and efficient manufacturing technology in a wide variety of markets. Although the performance requirements, which are imposed by the current applications, are tight, the future performance requirements are expected to be even more challenging. These print requirements are related to the jetted drop properties, namely, drop velocity, drop volume, drop velocity consistency, productivity, and reliability. Meeting these performance requirements is restricted by several operational issues that are associated with the design and the operation of inkjet printheads. Major issues that are usually encountered are residual vibrations and crosstalk among ink channels. These result in a poor printing quality for high-speed printing. The main objective is to design a feedforward control strategy such that variations in the velocity and volume of the jetted drops are minimized. In this article, an experimental-based feedforward control scheme is proposed to improve the performance of a professional inkjet printer.
PubDate: 2013-04-21T00:30:34Z
- Abstract: Publication date: July 2013
- A robust extended H∞ filtering approach to multi-robot cooperative localization in dynamic indoor environments
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
Author(s): Yan Zhuang , Zidong Wang , Haiyang Yu , Wei Wang , Stanislao Lauria
Multi-robot cooperative localization serves as an essential task for a team of mobile robots to work within an unknown environment. Based on the real-time laser scanning data interaction, a robust approach is proposed to obtain optimal multi-robot relative observations using the Metric-based Iterative Closest Point (MbICP) algorithm, which makes it possible to utilize the surrounding environment information directly instead of placing a localization-mark on the robots. To meet the demand of dealing with the inherent non-linearities existing in the multi-robot kinematic models and the relative observations, a robust extended H ∞ filtering (REHF) approach is developed for the multi-robot cooperative localization system, which could handle non-Gaussian process and measurement noises with respect to robot navigation in unknown dynamic scenes. Compared with the conventional multi-robot localization system using extended Kalman filtering (EKF) approach, the proposed filtering algorithm is capable of providing superior performance in a dynamic indoor environment with outlier disturbances. Both numerical experiments and experiments conducted for the Pioneer3-DX robots show that the proposed localization scheme is effective in improving both the accuracy and reliability of the performance within a complex environment.
PubDate: 2013-04-21T00:30:34Z
- Abstract: Publication date: July 2013
- Subspace identification analysis of RFX and T2R reversed-field pinches
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
Author(s): K. Erik J. Olofsson , Anton Soppelsa , Tommaso Bolzonella , Giuseppe Marchiori
Input–output datasets from two magnetic confinement fusion (MCF) experiments of the reversed-field pinch (RFP) type are examined. The RFP datasets, which are samples of the distributed magnetic field dynamics, are naturally divided into many smaller batches due to the pulsed-plasma operation of the experiments. The two RFP experiments considered are (i) EXTRAP T2R (T2R) with 64 inputs and 64 outputs and (ii) RFX-mod (RFX) with 192 inputs and 192 outputs. Both T2R and RFX are magnetohydrodynamically unstable and operates under magnetic feedback with optional dither injection. Using subspace system identification techniques and randomised cross-validation (CV) methods to minimise the generalisation error, state-space orders of the empirical systems are suggested. These system orders are compared to “stabilisation diagrams” commonly used in experimental modal analysis practice. The relation of the CV system order to the decay of the singular values from the subspace method is observed. Both (i) stable vacuum diffusion and (ii) unstable plasma response datasets are analysed. Apparent simulation and prediction errors are quantified for both cases using a deviation-accounted-for index. These results are purely data-driven. A simple approach towards exploitation of the subspace techniques for finite-element model refinement and data confrontation is presented.
PubDate: 2013-04-17T00:30:35Z
- Abstract: Publication date: July 2013
- Detection and reduction of middle frequency resonance for an industrial servo
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
This work proposes a novel strategy for middle frequency resonance detection and reduction for the speed control of industrial servo systems. The report includes an analysis of the drawbacks of the traditional resonance reduction method based on an adaptive notch filter in the middle frequency range, and the main drawback is summarized as the difference between the resonance frequency and the oscillation frequency. In the proposed method, a self-tuning low-pass filter with a corner frequency determined using FFT results and several self-tuning rules is introduced in the speed feedback path. Consequently, the effective range of the adaptive filter is extended across the middle frequency range. The simulation and experimental results show that the frequency detection is accurate, and the resonances are successfully reduced during steady-state and dynamic speeds.
PubDate: 2013-04-13T00:30:38Z
- Abstract: Publication date: July 2013
- Sensor fault detection and isolation in a thermal power plant steam separator
- Abstract: Publication date: July 2013
Source:Control Engineering Practice, Volume 21, Issue 7
A fault detection and isolation approach, specially designed for steam separators in thermal power plants, is presented in the paper. The first step of the proposed algorithm is to identify the process. Because of the presence of sporadic high-intensity measurement noise (outliers), the paper proposes a robust version of recursive identification. Starting from the parameter vector of the identified model, the second step of the proposed procedure has the form of a data-driven fault detector. This particular fault detection and isolation approach was implemented at TEKOB1 Kostolac Thermal Power Plant in Serbia, whose nominal power output is 330MW.
PubDate: 2013-04-13T00:30:38Z
- Abstract: Publication date: July 2013
- IFC ‐ Editorial Board / Funding body / agreements policies
- Abstract: Publication date: June 2013
Source:Control Engineering Practice, Volume 21, Issue 6
PubDate: 2013-04-09T00:30:39Z
- Abstract: Publication date: June 2013
- OBC ‐ Autogenerate contents and barcode
- Abstract: Publication date: June 2013
Source:Control Engineering Practice, Volume 21, Issue 6
PubDate: 2013-04-09T00:30:39Z
- Abstract: Publication date: June 2013
- Robust finite-frequency H2 analysis of uncertain systems with application to flight comfort analysis
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
In many applications, design or analysis is performed over a finite-frequency range of interest. The importance of the H 2 norm highlights the necessity of computing this norm accordingly. This paper provides different methods for computing upper bounds of the robust finite-frequency H 2 norm for systems with structured uncertainties. An application of the robust finite-frequency H 2 norm for a comfort analysis problem of an aero-elastic model of an aircraft is also presented.
PubDate: 2013-03-31T23:13:54Z
- Abstract: June 2013
- SCADA system with predictive controller applied to irrigation canals
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
This paper applies a model predictive controller (MPC) to an automatic water canal with sensors and actuators controlled by a PLC network (programmable logic controller), and supervised by a SCADA system (supervisory control and data acquisition). This canal is composed by a set of distributed sub-systems that control the water level in each canal pool, constrained by discharge gates (control variables) and water off-takes (disturbances). All local controllers are available through an industrial network managed by the SCADA system, where the centralized predictive controller runs. In this paper a complete new platform connecting the SCADA supervisory system and the MATLAB software (named SCADA–MATLAB platform) is built, in order to provide the usual SCADA systems with the ability to handle complex control algorithms. The developed MPC-model presents a novelty in the control of irrigation canals as it allows the use of industrial PLCs to implement high complex controllers, through the new developed SCADA–MATLAB platform. Experimental results demonstrate the reliability and effectiveness of the proposed strategy in real-life typical situations, including gate malfunctioning and extreme water off-take conditions.
PubDate: 2013-03-28T00:11:35Z
- Abstract: June 2013
- Experimental validation of the discrete-time MCS adaptive strategy
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
This paper is concerned with the implementation and experimental validation of a discrete-time model reference adaptive control strategy, known as Minimal Control Synthesis (MCS) algorithm. After discussing the proof of stability of the algorithm when applied to discretized models of continuous-time plants, the problem of controlling a highly nonlinear electro-mechanical device is taken as a representative case of study. It is shown that the discrete-time MCS is an effective strategy to solve the problem while guaranteeing robustness to unmodeled nonlinear dynamics over a wide range of test manoeuvres.
PubDate: 2013-03-24T00:10:21Z
- Abstract: June 2013
- Fault-tolerant cruise control of electric vehicles with induction motors
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
A fault-tolerant control scheme is proposed for the cruise control of electric vehicles (trains, cars) that make use of induction motors. It relies on a rotor speed reference generator and on a flux observer which is adaptive with respect to the uncertain rotor and stator resistances and to the load torque as well. The closed loop on-line identification of those three critical uncertain parameters allows for: (i) on-line estimating and imposing the motor flux modulus reference value which minimizes power losses at steady-state and improves power efficiency; (ii) the on-line detection of speed sensor faults as well as the fast switching on redundant motor speed sensors. CarSim simulations illustrate the effectiveness of the proposed approach.
PubDate: 2013-03-24T00:10:21Z
- Abstract: June 2013
- Demand side management of a run-of-mine ore milling circuit
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
Increasing electricity costs coupled with lower prices for some metals such as platinum group metals require a reevaluation of the operation of grinding processes. Demand side management (DSM) has received increasing attention in the field of industrial control as an opportunity to reduce operating costs. DSM through grinding mill power load shifting is presented in this paper using model predictive control and a real-time optimizer. Simulation results indicate that mill power load shifting can potentially achieve cost reductions of $9.90 per kg of unrefined product when applied to a run-of-mine (ROM) ore milling circuit processing platinum bearing ore. DSM is however still not economically feasible when there is a demand to continuously run the milling circuit at maximum throughput.
Highlights ► Power load shifting was implemented on a run-of-mine ore milling circuit model. ► A real time optimizer and model predictive controller were used. ► Operating costs can be reduced for mills running below maximum capacity. ► At 93% of maximum throughput cost reductions of $9.90kg can be achieved. ► Power load shifting is not economically feasible when there is a demand to continuously run the milling circuit at maximum throughput.
PubDate: 2013-03-24T00:10:21Z
- Abstract: June 2013
- Autonomous airship path following control: Theory and experiments
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
A novel path following control method related to the planar and spatial motions for an underactuated autonomous airship is presented. First, the trajectory linearisation control (TLC) theory is briefly described and the dynamic model of the airship is introduced. Then, based on the model, a path following strategy that integrates the guidance-based path following principle and the TLC theory is deduced. The designed control system possesses a cascaded structure composed of a guidance loop, an attitude kinematics loop and a dynamics control loop. Stability analysis shows that the controlled closed-loop system is asymptotically stable. Finally, experimental flight results for the airship following typical paths are illustrated to verify the effectiveness of the proposed approach.
PubDate: 2013-03-24T00:10:21Z
- Abstract: June 2013
- Quasi-LPV modeling, identification and control of a twin rotor MIMO system
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
This paper describes the quasi-linear parameter varying (quasi-LPV) modeling, identification and control of a Twin Rotor MIMO System (TRMS). The non-linear model of the TRMS is transformed into a quasi-LPV system and approximated in a polytopic way. The unknown model parameters have been calibrated by means of the non-linear least squares identification approach and validated against real data. Finally, an LPV state observer and state-feedback controller have been designed using an LPV pole placement method based on LMI regions. The effectiveness and performance of the proposed control approach have been proved both in simulation and on the real set-up.
Highlights ► The non-linear model of the TRMS is improved and used for obtaining a quasi-LPV model. ► The quasi-LPV model is calibrated using data collected from the real lab set-up. ► The LMI-based control theory is applied for designing the controller and observer. ► The proposed modeling, identification and control are applied to a real TRMS. ► The whole procedure can be a guide for the control of complex non-linear systems.
PubDate: 2013-03-24T00:10:21Z
- Abstract: June 2013
- A model identification scheme for driver-following dynamics in road traffic
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
The driver-following, or car-following, model is one of the most fundamental driver behavior models that are applied in intelligent transport applications. Its fidelity determines the applicability of microscopic traffic simulators, where the model is often implemented to mimic real traffic. Meanwhile, the behavioral model is fundamental to the development of advanced driving assistance systems (ADAS). This paper develops a dynamic model identification approach based on iterative usage of the extended Kalman Filtering (EKF) algorithm. Among other things, this allows to carry out model identification using a rather general optimization objective on the whole physical states of the following vehicle. In particular, the method is established on the basis of the equivalence between the Kalman filter and the recursive least squares (RLS) method in a specific context of parameter identification. To illustrate the method, two car-following models are studied in numerical experiments using real car-following data. The method has shown advantages in replication and prediction of vehicle dynamics in car-following over the conventional approaches. It has also the potential to be further extended for building tactical driving controllers in intelligent transportation applications.
PubDate: 2013-03-24T00:10:21Z
- Abstract: June 2013
- Integrated FDD system for valve stiction in a paperboard machine
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
The performance of a modern industrial plant can be severely affected by the performance of its key devices, such as valves. In particular, valve stiction can cause poor performance in control loops and can consequently lower the efficiency of the plant and the quality of the product. This paper presents an integrated FDD system for valve stiction which employs various FDD methods in a parallel configuration. A reliability index was integrated into each method in order to estimate their degree of influence in the final diagnosis of the system. Each method and the integrated system were tested using industrial data.
Highlights ► We made a comparison study of FDD algorithms for valve stiction. ► We describe a reliability index for the studied FDD methods. ► We propose implementing several FDD algorithms and reliability indices in an Integrated FDD system for valve stiction. ► The integrated system provides more consistent and reliable results.
PubDate: 2013-03-24T00:10:21Z
- Abstract: June 2013
- Intelligent controls for electro-hydraulic poppet valves
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
This paper describes an intelligent controller that combines an auto-calibration state-trajectory-based control method with a simple algorithm that enables fault detection. The application of the controller to achieve intelligent electronic pressure control in a fluid power system is included. More specifically, the proposed control algorithm is designed to learn the inverse input-state map of an Electro-Hydraulic Poppet Valve (EHPV) with the aid of a Nodal Link Perceptron Network (NLPN). While in operation, the controller enforces the tracking of a desired hydraulic supply pressure profile at the same time that it learns the inverse input-state calibration map and monitors the latter for deviations from prescribed bounds. The tracking performance of the auto-calibration scheme is validated experimentally and the fault detection algorithm is explored via a computer simulation.
PubDate: 2013-03-24T00:10:21Z
- Abstract: June 2013
- Online fault diagnosis using recursive subspace identification: Application to a dam-gallery open channel system
- Abstract: June 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 6
The paper presents an online strategy for sensor and/or actuator fault detection and isolation applied to a dam-gallery. A recursive subspace identification algorithm is used to estimate the dam-gallery model parameters. The main contribution consists in developing a specific identification scheme, insensitive to a certain type of faults. That is, the identified parameters are invariant to the faults. A fault estimation procedure is proposed to detect potential faults. The proposed approach appears to be suitable for open channel systems for which the characteristics are not easily measurable.
PubDate: 2013-03-24T00:10:21Z
- Abstract: June 2013
- IFC ‐ Editorial Board / Funding body / agreements policies
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
PubDate: 2013-03-16T00:10:23Z
- Abstract: May 2013
- Synthesis of loss-free resistors based on sliding-mode control and its applications in power processing
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
A systematic procedure to synthesize loss-free resistors (LFRs) based on sliding-mode control (SMC) of DC–DC switching converters is presented. Candidates for LFR operation are determined from the topological constraints imposed in a power converter by inducing sliding-mode motions. Two examples illustrate the use of the synthesized LFRs in power processing. The first one shows the application of the LFR as a pre-regulator stage for power factor correction (PFC) in single-phase circuits, while the second one describes its use for DC impedance matching in photovoltaic (PV) systems.
PubDate: 2013-03-16T00:10:23Z
- Abstract: May 2013
- Robust input–output sliding mode control of the buck converter
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
An input–output based feedback controller is proposed for the sliding mode control of a large class of switched systems. The method avoids state measurements, or the use of observers, and it extends the sliding mode control design methodology to input–output descriptions of the plant. The approach regards the average Generalized Proportional Integral (GPI) output feedback controller as a guide for defining the switched implementation of the average sliding mode features via a Sigma–Delta modulation strategy. The considerations are circumscribed to the class of differentially flat systems. Experimental results are presented for a trajectory tracking problem on a DC-to-DC switched power supply of the “buck” type with unknown loads subject to abrupt variations.
PubDate: 2013-03-16T00:10:23Z
- Abstract: May 2013
- Sliding mode control with gain adaptation—Application to an electropneumatic actuator
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
A novel adaptive sliding mode controller is proposed for a class of nonlinear MIMO systems with bounded uncertainties/perturbations whose bounds are unknown. The adaptation algorithm ensures that the gain is not overestimated, which leads to a reduction of chattering; furthermore, the controller ensures the establishment of a real sliding mode (which induces the practical stability of the closed-loop system). The algorithm is applied to position–pressure control of an electropneumatic actuator. The results of the experimental study are presented and confirmed the efficacy of the proposed adaptive sliding mode control.
PubDate: 2013-03-16T00:10:23Z
- Abstract: May 2013
- Variable structure systems techniques in applications VSS/SMC
- Abstract: Available online 1 March 2013
Publication year: 2013
Source:Control Engineering Practice
PubDate: 2013-03-04T00:12:23Z
- Abstract: Available online 1 March 2013
- Optimizing low-order controllers for haptic systems under delayed feedback
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
In this paper, a PD controller design for haptic systems under delayed feedback is considered. More precisely, a complete stability analysis of a haptic system where local dynamics are described by some second-order mechanical dynamics is presented. Next, using two optimization techniques ( H ∞ and stability, margin optimization) an optimal choice for the controller gains is proposed. The derived results are tested on a three degree-of-freedom real-time experimental platform to illustrate the theoretical results.
PubDate: 2013-03-04T00:12:23Z
- Abstract: May 2013
- Obstacle surpassing and posture control of a stair-climbing robotic mechanism
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
In this study, we propose a new kinematic control for a robotic stair-climbing mechanism which allows successful obstacle surpassing when faced with typical architectural barriers such as curbs, ramps or staircases while maintaining the passenger's comfort and the seat's inclination within security margins. The scheme also takes into account perturbations in the system due to the fact that the environment is not perfectly known. The actuated degrees of freedom in charge of the locomotion device and the posture device are controlled in a different way. The locomotion control is achieved with a feedforward term and a standard proportional derivative (PD) control position. The posture control is obtained with a novel variant of multilevel feedback controller design via a suitable combination of a Lyapunov feedback controller design along with a multilevel generalization of the sliding mode based Sigma–Delta ( Σ – Δ ) modulator coupled with an adequate selection of the trajectory of the center of mass. The main features of this novel kinematic control algorithm are: maintenance of the passenger comfort, high degree of perturbation rejection regarding modeling error, independence of the designed control law on the environment parameters, computational efficiency and minimal sensor requirements. Numerical simulations illustrate the performance of the proposed method when the prototype is to surpass an obstacle with different heights with the value of the height obstacle being unknown. Finally, experimental results validate the behavior of the prototype for, both, obstacle surpassing and posture control when the wheelchair prototype ascends a curb of 180mm.
PubDate: 2013-02-28T00:05:56Z
- Abstract: May 2013
- UNIT: A freely available system identification toolbox
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
This paper presents a Matlab-based software package for the estimation of dynamic systems. It has been developed primarily as a platform to support the objective evaluation of novel approaches relative to existing methods within a common software framework. This is designed to streamline comparisons. The work here provides an explanation of the toolbox's design and use together with an overview of the underlying supported models and algorithms. An application study involving a lightly damped resonant system and a simulation example involving two non-linear systems are also presented in order to illustrate the use and capabilities of the toolbox.
PubDate: 2013-02-28T00:05:56Z
- Abstract: May 2013
- Modeling and compensation of the machine directional register in roll-to-roll printing
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
For mass manufacturing of printed electronics using roll-to-roll printing, high-resolution register control among multi-layers is required. A mathematical model of a machine directional (MD) register was derived, where the compensation method was proposed to cancel out the upstream disturbance of the MD register. The proposed MD register model and compensator could be used to improve the performance of the MD register controller in multi-layer roll-to-roll printed electronics. The proposed compensator was experimentally verified at various operating conditions. The results show that the proposed compensator improves the control performance of the MD register in overcoming upstream disturbances
Graphical abstract
Highlights
PubDate: 2013-02-28T00:05:56Z
- Abstract: May 2013
- Improved DCT-based method for online detection of oscillations in univariate time series
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
Automatic oscillation detection for univariate time series is the very first step in detection and compensation of oscillations in process industries. This paper is motivated by our industrial experience of applying the discrete cosine transform (DCT)-based method for oscillation detection. An improved DCT-based method is proposed with three main modifications, namely, a revised hypothesis test based on the confidence interval of coefficient of variation, a fitness index to determine a dominant oscillation component, and a hypothesis test on the regularity of oscillation magnitudes. These modifications are also applicable to other oscillation detection methods in the literature. Moreover, an online oscillation detection method is proposed, with a mechanism by which the size of a supervision time window is adaptive to frequency variation of process variables. Industrial examples are provided to demonstrate the effectiveness of the two proposed methods.
PubDate: 2013-02-28T00:05:56Z
- Abstract: May 2013
- Power system stability enhancement by WAMS-based supplementary control of multi-terminal HVDC networks
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
This paper deals with supplementary control of a MTDC network designed for the stability enhancement of a AC power system. The proposed control is a WAMS-based control modulating the real and reactive power at the terminals of the DC network. Relevant control formulas have been derived for a linear multi-machine system model with the application of the direct Lyapunov method. Validity and robustness of the proposed control has been verified by computer simulation for a multi-machine test system using a nonlinear model and detailed modeling of power system components. The proposed control is robust and insensitive to changes in the network configuration and loading conditions in the AC power system. In the case, when more of the MTDC networks and/or the HVDC links are used in one interconnected power system the proposed stabilizing control produces additive damping i.e. each controlled network element contributes to the positive damping. Some practical aspects have also been discussed. The proposed WAMS-based stabilizing control of the MTDC network is innovative by both its main concept and the derivation of control formulas using the direct Lyapunov method.
Highlights ► MTDC networks can be used to enhance transient stability of AC power systems. ► The proposed control is insensitive to changes in the network configuration. ► The proposed control is insensitive to changes in the loading conditions. ► Each device controlled by proposed method contributes with positive damping. ► The proposed control can be realized as the WAMS-based supplementary control.
PubDate: 2013-02-28T00:05:56Z
- Abstract: May 2013
- Optimal fast-response sliding-mode control for flexible-substrate measurement
- Abstract: May 2013
Publication year: 2013
Source:Control Engineering Practice, Volume 21, Issue 5
In order to control bending radii of flexible substrates in displays, this paper presents an optimal fast-response sliding-mode control method. Maximum driving voltages are utilized in sliding-mode control based on a linear quadratic estimator. An optimal design for the threshold value and the reaching-law parameter are obtained by using a procedure of the fast-response regulation. Implementing the proposed method, this study measures electrical resistances for different widths of line patterns on polyethylene terephthalate/indium tin oxide substrates up to 11,000 bending times.
Highlights ► An optimal fast-response sliding-mode control (OFRSMC) method has been developed. ► We have successfully controlled bending radii of flexible substrates by OFRSMC. ► Electrical characteristics of flexible substrates for bending 11,000 times are presented.
PubDate: 2013-02-28T00:05:56Z
- Abstract: May 2013
