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Journal Cover Control Engineering Practice
   [18 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0967-0661
     Published by Elsevier Homepage  [2571 journals]   [SJR: 1.522]   [H-I: 59]
  • Control of human arm movement in machine-human cooperative welding process
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): YuKang Liu , YuMing Zhang
      This paper studies accurate control of human arm movement in machine-human cooperative control of GTAW process. An innovative teleoperated virtualized welding platform is utilized to conduct dynamic experiments to correlate the human welder arm movement with the visual signal input. An adaptive ANFIS model is proposed to model the intrinsic nonlinear and time-varying characteristic of the human welder response. A model based predictive control algorithm is then proposed and an analytical solution is derived. Human control experimental results verify that the proposed controller is able to track varying set-points and is robust under measurement and input disturbances.


      PubDate: 2014-10-12T07:09:25Z
       
  • Semi-active magnetorheological dampers for reducing response of high-speed
           railway bridges
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): M. Luu , M.D. Martinez-Rodrigo , V. Zabel , C. Könke
      To reduce the resonant response of high-speed railway bridges, semi-active magnetorheological dampers are proposed in this study. The elements are connected to the structure in a double beam configuration. An H ∞ control algorithm to drive magnetorheological damping forces of MR dampers is derived. Feasible solutions for an uncertain time-delay model are obtained by using standard linear matrix inequality techniques. Weight functions as a loop shaping procedure are also introduced in the feedback controllers to improve the tracking ability of magnetorheological damping forces. To this end, the effectiveness of magnetorheological dampers controlled by the proposed scheme, along with the effects of the uncertain and the time-delay parameters on the models, are evaluated and compared with the performance of fluid viscous dampers in similar applications reported in previous research through numerical simulations.


      PubDate: 2014-10-12T07:09:25Z
       
  • A simple output-feedback strategy for the control of perfused mammalian
           cell cultures
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Mihaela Sbarciog , Daniel Coutinho , Alain Vande Wouwer
      This paper presents a framework for the multivariable robust control of perfusion animal cell cultures. It consists of a cascade control structure and an estimation algorithm, which provides the unmeasurable variables needed in the design of the control law, and ensures the regulation of the cell and glucose concentrations at imposed levels by manipulating the bleed and the dilution rates. The cascade control structure uses a feedback linearizing controller in the inner loop and linear (PI) controllers in the outer loops, and requires the measurement of the cell concentration and the glucose concentration in the bioreactor. Two approaches are provided: the first one assumes the availability of an approximate model of the process kinetics and uses an extended Kalman filter (EKF) to estimate the system states; the second approach does not require the prior knowledge of the process kinetics. These are estimated from the available measurements using sliding mode observers (SMO). A receding horizon optimization algorithm is employed to (periodically) tune the gains of the outer loop controllers. The proposed framework is easy to implement and tune, and may be applied to a general class of perfusion cell culture systems. Its effectiveness and robustness are illustrated by means of simulation results.


      PubDate: 2014-10-12T07:09:25Z
       
  • On interval goal programming switching surface robust design for Integral
           Sliding Mode Control
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Alfredo Del Sole Lordelo , Heloise Assis Fazzolari
      This paper presents a systematic technique for Integral Sliding Mode Control design applied to linear time-invariant systems, subject to disturbances, whose uncertain parameters belong to closed intervals. This approach considers a computational optimization-based procedure for the switching surface design, formulated as an interval goal programming problem, equivalent to the interval Ackermann׳s equation for the robust eigenvalue placement problem. The design objective is the minimization of the overall deviation from the specified performance for the transient response of the controlled system, which is represented by a polytope of characteristic polynomials. The controllability of interval systems is also numerically treated within an interval analysis framework. An experimental implementation of this switching surface design technique was compared with a classic robust LMI-based design procedure of the switching surface in the position control of a DC motor, coupled to different loads, to illustrate its main features and efficiency.


      PubDate: 2014-10-12T07:09:25Z
       
  • Co-surge in bi-turbo engines: Measurements, analysis and control
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Andreas Thomasson , Lars Eriksson
      In parallel turbocharged V-engines, with two separate air paths connected before the throttle, an oscillation in the flow can occur. If the compressor operates close to the surge line, typically during low speed and high load, and a disturbance alters the mass flow balance, the compressors can begin to alternately go into surge. This phenomenon is called co-surge and is unwanted due to high noise and risk of turbocharger destruction. Co-surge is measured on a test vehicle in a chassis dynamometer and the system analyzed and modeled using a mean value engine model. The investigation shows that alternating compressor speeds have an important role in the prolonged oscillation. A reconstruction of the negative flow from measurements is made and compared to simulation results, showing similar amplitudes, and supports the model validation. A new co-surge detection algorithm is presented, suitable for a pair of sensors measuring either mass flow, boost pressure or turbo speed in the two air paths. Furthermore, a new controller is proposed that uses a model based feedforward for the throttle, together with wastegate actuation to force the compressor speeds together and improve balance at the recovery point. This has been shown to be sufficient for moderate to high pressure ratios over the throttle, and only for zero or very low pressure drop the use of bypass valves is necessary. The advantage of not opening the bypass valves is a smaller drop in boost pressure which also reduces the torque disturbance. The performance of the controller is evaluated both in simulation and in the test vehicle.


      PubDate: 2014-10-12T07:09:25Z
       
  • A novel intelligent controller for combating stiction in pneumatic control
           valves
    • Abstract: Publication date: December 2014
      Source:Control Engineering Practice, Volume 33
      Author(s): Puneet Mishra , Vineet Kumar , K.P.S. Rana
      Pneumatic control valve introduces limit cycles in process variables due to stiction nonlinearity. In this paper a novel stiction combating intelligent controller (SCIC) based on fuzzy logic has been proposed. The proposed technique reduces the complexity of the overall control scheme as it does not require any additional compensator. The SCIC controller is a variable gain fuzzy Proportional Integral (PI) controller making use of Takagi-Sugeno (TS) scheme. The performance of the SCIC controller has been investigated and compared with conventional PI controller on a laboratory scale flow process. SCIC controller outperformed PI controller and provided promising performance with lesser aggressive stem movement.


      PubDate: 2014-10-12T07:09:25Z
       
  • IFC - Editorial Board / Funding body / agreements policies
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32




      PubDate: 2014-10-12T07:09:25Z
       
  • Active vibration isolation feedback control for Coriolis Mass-Flow Meters
    • Abstract: Publication date: December 2014
      Source:Control Engineering Practice, Volume 33
      Author(s): L. van de Ridder , M.A. Beijen , W.B.J. Hakvoort , J. van Dijk , J.C. Lötters , A. de Boer
      Active Vibration Isolation Control (AVIC) can be used to reduce the transmissibility of external vibrations to internal vibrations. In this paper a proposal is made for integrating AVIC in a Coriolis Mass-Flow Meter (CMFM). Acceleration feedback, virtual mass and virtual skyhook damping are added to a passively suspended CMFM, resulting in a lowered suspension frequency. In addition, position feedback of the internal deformation is used to damp the internal mode. The controller design is based on a simplified model and is validated on an experimental setup. Results show that the sensitivity to external vibrations is reduced by 40dB for the RMS measurement error.


      PubDate: 2014-10-12T07:09:25Z
       
  • Formal representation of GRAFCET to automatically generate control code
    • Abstract: Publication date: December 2014
      Source:Control Engineering Practice, Volume 33
      Author(s): Frank Schumacher , Alexander Fay
      Within the engineering of control code, model-based approaches become more and more important. Basically GRAFCET serves as a suitable modeling language but lacks an exhaustive formal representation of its structure and dynamic behavior since current approaches only consider subclasses of GRAFCET. Within this article the authors depict a systematic approach for an exhaustive formal model of GRAFCET, specifically by taking enclosing steps, forcing orders and time constraints into account. Based on this formal model of GRAFCET a method together with a tool framework are presented allowing for the automatic generation of control code.


      PubDate: 2014-10-12T07:09:25Z
       
  • 2-DOF skew control of boom cranes including state estimation and reference
           trajectory generation
    • Abstract: Publication date: December 2014
      Source:Control Engineering Practice, Volume 33
      Author(s): Ulf Schaper , Christina Dittrich , Eckhard Arnold , Klaus Schneider , Oliver Sawodny
      In small and midsize harbors, boom cranes are used for multiple applications. These include bulk cargo handling and container transloading. For container handling, a spreader is attached to the crane hook. While grabbing a container with the spreader, both the position and the orientation of the spreader and the container must match. The spreader orientation is usually referred-to as skew angle. Other synonyms are yaw angle or spreader heading. The skew angle is controlled using a hook-mounted rotator motor. Since wind, impact, and uneven load distribution can cause skew vibrations, active skew control is desirable for facilitating crane operation, improving positioning accuracy, and increasing turnover. Different skewing device designs are used for different types of cranes. This contribution presents the skew dynamics on a boom crane along with an actuator model and a sensor configuration. Subsequently a two-degrees of freedom control concept (2-DOF) is derived which comprises a state observer for the skew dynamics, a reference trajectory generator, and a feedback control law. The control system is implemented on a Liebherr mobile harbor crane and its effectiveness is validated with multiple test drives.


      PubDate: 2014-10-12T07:09:25Z
       
  • OBC - Autogenerate contents and barcode
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32




      PubDate: 2014-10-12T07:09:25Z
       
  • Differential geometry based active fault tolerant control for aircraft
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): P. Castaldi , N. Mimmo , S. Simani
      This work shows how to use a differential geometry tool to design a novel nonlinear active fault tolerant flight control system for aircraft. The proposed control scheme consists of two main subsystems: a controller, which is designed for the nominal plant, and a fault detection and diagnosis module, which provides fault estimation. A further feedback loop exploits the fault estimation to accommodate faults affecting the system. The estimate convergence and the stability of the active fault tolerant flight controller are theoretically proved. Finally, high fidelity simulations show the effectiveness of the scheme.


      PubDate: 2014-10-12T07:09:25Z
       
  • Cooperative allocation and guidance for air defence application
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): S. Le Ménec , H.-S. Shin , K. Markham , A. Tsourdos , H. Piet-Lahanier
      This project proposes a centralised algorithm to design cooperative allocation strategies and guidance laws for air defence applications. Scenarios in naval and ground context have been defined for performance analysis by comparison to a benchmark target allocation policy. The cooperative target allocation algorithm is based on the following features: No Escape Zones (differential game NEZ) computation to characterise the defending missile capturability characteristics; In Flight (re) Allocation (IFA algorithm, late committal guidance) capability to deal with target priority management and pop up threats; capability to generate and counter alternative target assumptions based on concurrent beliefs of future target behaviours, i.e. Salvo Enhanced No Escape Zone (SENEZ) algorithm. The target trajectory generation has been performed using goal oriented trajectory extrapolation techniques. The target allocation procedure is based on minimax strategy computation in matrix games.


      PubDate: 2014-10-12T07:09:25Z
       
  • Simultaneous compensation of hysteresis and creep in a single
           piezoelectric actuator by open-loop control for quasi-static space active
           optics applications
    • Abstract: Publication date: December 2014
      Source:Control Engineering Practice, Volume 33
      Author(s): Xuan Wang , Valérie Pommier-Budinger , Aurélien Reysset , Yves Gourinat
      Owing to their excellent properties piezoelectric actuators are studied as embedded elements for the quasi-statically active shape control of spatial optical mirrors. However, unwanted nonlinear effects in piezoelectric actuators, i.e., hysteresis and creep, severely limit their performance. This paper aims at developing a control methodology to compensate hysteresis and creep in a piezoelectric actuator simultaneously for quasi-static space active applications. In the methodology developed, hysteresis and creep behaviors are successively compensated by open-loop control. First, a derivative Preisach model is proposed to accurately portray the hysteresis while requiring relatively few measurements and describing the detachment between major and minor loops. The inverse derivative Preisach model is derived and inserted in open-loop to achieve hysteresis compensation. Then, the creep in the hysteresis compensated piezoelectric actuator is described by the use of a nonlinear viscoelastic model and a low pass filter is suggested to eliminate the effect of the inverse derivative Preisach model on the step reference input. To invert the creep model, the concept of “input relaxation” is implemented and an inverse multiplicative structure allows identifying the parameters of the inverse model while circumventing the difficulty of a mathematical computation. Finally, by cascading the low pass filter, the inverse model of creep and the inverse derivative Preisach model one after the other with the single piezoelectric actuator, the simultaneous compensation of hysteresis and creep is achieved. Experimental results show that in the case of step-like reference signals the hysteresis and the creep in a piezoelectric actuator can be significantly reduced at the same time. It implies that the developed methodology is effective and feasible in space active optics applications for which quasi-static distortions need to be compensated.


      PubDate: 2014-10-12T07:09:25Z
       
  • Analysis and design of guidance-strategy for dynamic soaring with UAVs
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Xian-Zhong Gao , Zhong-Xi Hou , Zheng Guo , Rong-Fei Fan , Xiao-Qian Chen
      Dynamic soaring is an effective method to extract energy from wind shear to reduce energy consumption and extend flight duration. However, the design of the guidance-strategy for autonomous dynamic soaring is still suffering from the heavy computation load. In order to solve this problem, the aim of this paper is to propose a simple method to generate the guidance-strategy for autonomous dynamic soaring. Firstly, the flight path of dynamic soaring is modeled and solved by an open source optimal software named GPOPS. Secondly, the cycle of dynamic soaring is divided into four piecewise trajectories, and the characteristics of each are determined by some simple equations. Thirdly, the guidance-strategy based on the results of these equations is summarized. Simulation results indicate that the proposed guidance-strategy can present the characteristics of optimal flight very well, and it is practical and easy to be implemented by the on-board computer of Unmanned Aerial Vehicles for its simplicity.


      PubDate: 2014-10-12T07:09:25Z
       
  • Special section on aerospace control applications
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Paolo Castaldi , Radhakant Padhi , Antonio Tsourdos , Houria Siguerdidjane



      PubDate: 2014-10-12T07:09:25Z
       
  • Model predictive control of cooperative vehicles using systematic search
           approach
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Y. Rochefort , H. Piet-Lahanier , S. Bertrand , D. Beauvois , D. Dumur
      This paper describes the guidance law design of a group of autonomous cooperative vehicles using model predictive control. The developed control strategy allows one to find a feasible near optimal control sequence with a short and constant computation delay in all situations. The control strategy takes other vehicles predicted positions into account for cooperation purpose. Numerical simulations are provided where a group of quadrotors must reach several way-points while avoiding obstacles and collisions inside the group. Results obtained using a realistic model of small quadrotors show that the approach could be usable in practice.


      PubDate: 2014-10-12T07:09:25Z
       
  • Comfort-based fuzzy control optimization for energy conservation in HVAC
           systems
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Sajid Hussain , Hossam A. Gabbar , Daniel Bondarenko , Farayi Musharavati , Shaligram Pokharel
      The work presented herein illustrates the use of computational intelligence and optimization approaches for improving the fuzzy controller׳s performance in architectural heating, ventilation, and air conditioning system (HVAC). The primary purpose of the performed research is to find a method to moderate the energy use without compromising the comforts of the inhabitants. The control design used to meet this purpose includes the predicted mean vote (PMV) and predicted percentage dissatisfied (PPD) indices. The software of choice for evaluating PMV and PPD is EnergyPlus. Whereas, for the fuzzy controller and the evolutionary optimization framework, the co-simulation tool with building controls virtual test bed (BCVTB) is used in conjunction with Simulink. The ensuing comparison between EnergyPlus׳s thermal control of HVAC and our fuzzy approach is the outcome of the present research.


      PubDate: 2014-10-12T07:09:25Z
       
  • Design of event-based PI-P controllers using interactive tools
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Ángel Ruiz , Jorge Eugenio Jiménez , José Sánchez , Sebastián Dormido
      In the field of event-based control, the tuning and synthesis of controllers represent a challenging task where the lack of specific computer-aided design tools makes very difficult the consolidation of emerging approaches. Under this scenario, it recently proposed the PI-P control strategy, a promising alternative which provides the designer with a practical design and an intuitive tuning methodology. This work addresses the design task of PI-P event-based controllers through the use of interactive tools. To this aim, first, a new interactive tool is provided. The tool is the result of implementing the theoretical developments of previous researches with the aim of consolidating the strategy. Second, the tool is used to analyze in detail the design paradigm through their main trade-offs between performance and robustness. The usefulness of analyses developed is experimentally demonstrated through several meaningful designs for typical industrial examples.


      PubDate: 2014-10-12T07:09:25Z
       
  • Controller designs for bilateral teleoperation with input saturation
    • Abstract: Publication date: December 2014
      Source:Control Engineering Practice, Volume 33
      Author(s): Seung-Ju Lee , Hyo-Sung Ahn
      Input saturation raises a stability issue in a bilateral teleoperation system when a master robot whose motion is induced by a human operator moves fast in abnormal situation and a slave robot cannot follow the motion command due to the input saturation. In this paper, we conduct rigorous stability analyses of the teleoperation system under the input saturation. We first extend analysis of teleoperation scheme proposed in Chopra and Spong (2004) to a case of the input saturation, in which analysis is valid for a local operation region whose size is dependent on the input capacity. We further develop a new control scheme that guarantees the stability for a global operation region. Therefore, the proposed control scheme can deal with extreme cases, e.g., the speed of motion of the master robot can be substantially greater than the actuator capability of the slave robot. Simulations and experiments are subsequently conducted to verify the effectiveness of the analyses.


      PubDate: 2014-10-12T07:09:25Z
       
  • Parallel implementations of the fast gradient method for high-speed MPC
    • Abstract: Publication date: December 2014
      Source:Control Engineering Practice, Volume 33
      Author(s): Helfried Peyrl , Alessandro Zanarini , Thomas Besselmann , Junyi Liu , Marc-Alexandre Boéchat
      The potential of the fast gradient method for solving linear quadratic model predictive control (MPC) problems in the sub-millisecond range was only recently recognised by Richter et al. This paper aims to push the execution-time limit even further by exploiting the computational power offered by parallel computing architectures. In particular, scalable and adaptive implementations of gradient-based optimisation methods are presented for both multi-core CPUs and field programmable gate arrays. The proposed parallel implementations broaden the applicability of MPC to problems that were considered out-of-reach till recent years.


      PubDate: 2014-10-12T07:09:25Z
       
  • Optimal control of a half-circular compliant legged monopod
    • Abstract: Publication date: December 2014
      Source:Control Engineering Practice, Volume 33
      Author(s): Yasemin Ozkan Aydin , Afsar Saranli , Yigit Yazicioglu , Uluc Saranli , Kemal Leblebicioğlu
      This paper investigates an optimal control strategy for the dynamic locomotion of a simplified planar compliant half-circular legged monopod model. We first present a novel planar leg model which incorporates rolling kinematics and a new compliance model, motivated by the use of similar leg designs on existing platforms. Two locomotion tasks, moving at a prescribed horizontal velocity and a one-shot jump to maximum possible height or length, are then investigated within this model. The designs of two high-level optimal controllers for these tasks are then described to investigate the performance and stability of resulting behaviors, based on the optimization of trajectory parameters for a closed-loop low-level Proportional-Derivative controller at the hip. Our results show that with these optimized parameters the robot can achieve stable locomotion at a desired horizontal velocity and can successfully jump over and across a specified height and length. Finally, the composition of objective functions capturing multiple criteria is also investigated for the one-shot jump task.


      PubDate: 2014-10-12T07:09:25Z
       
  • Estimation-based ILC applied to a parallel kinematic robot
    • Abstract: Publication date: December 2014
      Source:Control Engineering Practice, Volume 33
      Author(s): Johanna Wallén Axehill , Isolde Dressler , Svante Gunnarsson , Anders Robertsson , Mikael Norrlöf
      Estimation-based iterative learning control (ILC) is applied to a parallel kinematic manipulator known as the Gantry–Tau parallel robot. The system represents a control problem where measurements of the controlled variables are not available. The main idea is to use estimates of the controlled variables in the ILC algorithm, and in the paper this approach is evaluated experimentally on the Gantry–Tau robot. The experimental results show that an ILC algorithm using estimates of the tool position gives a considerable improvement of the control performance. The tool position estimate is obtained by fusing measurements of the actuator angular positions with measurements of the tool path acceleration using a complementary filter.


      PubDate: 2014-10-12T07:09:25Z
       
  • Measurement noise filtering for common PID tuning rules
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): V. Romero Segovia , T. Hägglund , K.J. Åström
      Measurement noise generates undesired control activity resulting in wear of actuators and reduced performance. The effects of measurement noise can be alleviated by filtering the measurement signal. New criteria based on the trade-offs between performance, robustness, and attenuation of measurement noise are proposed for assessment of the design. Simple rules for calculating the filter time constant based on the nominal process model and the nominal controller are derived and a complete tuning procedure is proposed. The tuning procedure accounts for the effects of filtering. It is applied to well-known tuning procedures such as Lambda, SIMC, and AMIGO. The results are illustrated by experiments.


      PubDate: 2014-09-05T00:08:42Z
       
  • OBC - Autogenerate contents and barcode
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31




      PubDate: 2014-09-05T00:08:42Z
       
  • Sensor fault detection and isolation for aircraft control systems by
           kinematic relations
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): L. Van Eykeren , Q.P. Chu
      This paper presents a new approach to Fault Detection and Isolation (FDI) for sensors of aircraft. In the most general case, fault detection of these sensors on modern aircraft is performed by a logic that selects one of, or combines, the three redundant measurements. Such a method is compliant with current airworthiness regulations. However, in the framework of the global aircraft optimization for future and upcoming aircraft, it could be required, e.g., to extend the availability of sensor measurements. Introducing a form of analytical redundancy of these measurements can increase the fault detection performance and result in a weight saving of the aircraft. This can be achieved by exploiting the knowledge of the kinematic relations between the measured variables. These relations are exactly known giving the advantage that no model-mismatches need to be accounted for. Furthermore these relations are valid over the whole flight envelope and general for any type of aircraft. Two example applications will be presented, showing the applicability of the method for the FDI of air data sensors and measurements of the inertial reference unit.


      PubDate: 2014-09-05T00:08:42Z
       
  • A non-conservative H−/H∞ solution for early and robust fault
           diagnosis in aircraft control surface servo-loops
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): D. Henry , J. Cieslak , A. Zolghadri , D. Efimov
      The presented work is undertaken within the FP7-ADDSAFE (Advanced Fault Diagnosis for Sustainable Flight Guidance and Control) project, a European collaborative project that aims to propose new fault diagnosis techniques for AIRBUS aircraft that could significantly advance the aircraft performance, e.g. by optimizing the aircraft structural design (weight saving) or decreasing its environmental footprint (e.g. less fuel consumption and noise). The paper discusses the design of a model-based fault detection scheme for robust and early detection of faults in aircraft control surfaces servo-loop. The proposed strategy consists of two fault detectors: The first fault detector is based on a H − / H ∞ residual generator that maximizes sensitivity to any kind of control surface servo-loop faults whilst simultaneously minimizes the influence of unknown inputs. The second fault detector consists of a pure H ∞ residual generator that is sensitive to a restricted set of faults and robust to unknown inputs. By such a structured strategy, it is shown that it is possible to discriminate between different fault types occurring in the control surfaces servo-loop. Monte-Carlo campaigns from a highly representative simulator provided by AIRBUS as well as experimental results obtained on AIRBUS test facilities demonstrate the fault detection performance, robustness and viability of the proposed technique.


      PubDate: 2014-09-05T00:08:42Z
       
  • Bridging the gap between theory and practice in LPV fault detection for
           flight control actuators
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Bálint Vanek , András Edelmayer , Zoltán Szabó , József Bokor
      Two different approaches for fault detection, the geometric and the detection filter based methods, are compared in the paper from practical aspects, using the linear parameter-varying (LPV) framework. Presenting two designs allows a comparison of global, system level, and local component level fault detection methods with special emphasis on their relevance to aircraft industry. Practical engineering design decisions are highlighted via applying them to a high-fidelity commercial aircraft problem. The successive steps of the design, including fault modeling, LPV model generation, and LPV FDI filter synthesis, including implementation aspects, are discussed. Results are presented according to the industrial assessment perspectives phrased within the EU ADDSAFE project.


      PubDate: 2014-09-05T00:08:42Z
       
  • LPV model-based robust diagnosis of flight actuator faults
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Andreas Varga , Daniel Ossmann
      A linear parameter-varying (LPV) model-based synthesis, tuning and assessment methodology is developed and applied for the design of a robust fault detection and diagnosis (FDD) system for several types of flight actuator faults such as jamming, runaway, oscillatory failure, or loss of efficiency. The robust fault detection is achieved by using a synthesis approach based on an accurate approximation of the nonlinear actuator–control surface dynamics via an LPV model and an optimal tuning of the free parameters of the FDD system using multi-objective optimization techniques. Real-time signal processing is employed for identification of different fault types. The assessment of the FDD system robustness has been performed using both standard Monte-Carlo methods as well as advanced worst-case search based optimization-driven robustness analysis. A supplementary industrial validation performed on the AIRBUS actuator test bench for the monitoring of jamming, confirmed the satisfactory performance of the FDD system in a true industrial setting.


      PubDate: 2014-09-05T00:08:42Z
       
  • Development and application of sliding mode LPV fault reconstruction
           schemes for the ADDSAFE
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Halim Alwi , Christopher Edwards
      This paper describes the development and the evaluation of a robust sliding mode observer fault detection scheme applied to an aircraft benchmark problem as part of the ADDSAFE project. The ADDSAFE benchmark problem which is considered in this paper is the yaw rate sensor fault scenario. A robust sliding mode sensor fault reconstruction scheme based on an LPV model is presented, where the fault reconstruction signal is obtained from the so-called equivalent output error injection signal associated with the observer. The development process includes implementing the design using AIRBUS׳s the so-called SAO library which allows the automatic generation of flight certifiable code which can be implemented on the actual flight control computer. The proposed scheme has been subjected to various tests and evaluations on the Functional Engineering Simulator conducted by the industrial partners associated with the ADDSAFE project. These were designed to cover a wide range of the flight envelope, specific challenging manoeuvres and realistic fault types. The detection and isolation logic together with a statistical assessment of the FDD schemes are also presented. Simulation results from various levels of FDD developments (from tuning, testing and industrial evaluation) show consistently good results and fast detection times.


      PubDate: 2014-09-05T00:08:42Z
       
  • The European ADDSAFE project: Industrial and academic efforts towards
           advanced fault diagnosis
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Philippe Goupil , Andrés Marcos
      In this article a high-fidelity aircraft benchmark, developed by Airbus for advanced flight control related studies, is presented in relation to its evolution towards advanced fault diagnosis within a European 7th Framework Program project entitled “Advanced Fault Diagnosis for Sustainable Flight Guidance and Control (ADDSAFE)”. This European project was established to study and facilitate the transfer of model-based fault detection and diagnosis methods from Academia to Industry. The importance of the project arose on the one hand, due to the representativeness of the benchmark, and on the other hand, the industrial benchmarking and validation of the developed designs. The results presented in this article represent a quantitative measure of the success of the project since five of the developed designs were successfully validated in Airbus Verification and Validation (V&V) set-ups, and are currently undergoing further tests towards a possible real aircraft implementation.


      PubDate: 2014-09-05T00:08:42Z
       
  • Affine LPV-modeling for the ADDSAFE benchmark
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): S. Hecker , H. Pfifer
      General approaches are presented for approximating the nonlinear dynamics of a commercial aircraft model by affine linear parameter varying (LPV) models that are used for the design of fault detection and diagnosis (FDD) systems. One part of the paper deals with the approximation of the nonlinear actuator dynamics, where a simple analytic model is derived that accurately describes a given nonlinear, (partly) black-box model in the whole flight envelope. The second part presents a new two step approach for generating an affine LPV model for the nonlinear aircraft dynamics. Starting from a given trim-point in the flight envelope, the goal of the first step is to maximize the size of the region around this trim point, for which the simple affine LPV description is still valid. The second step then tries to further simplify the affine LPV model, which helps to reduce both the computational burden for FDD synthesis methods and the order of the linear fractional representations (LFRs) that are generated from these LPV models.


      PubDate: 2014-09-05T00:08:42Z
       
  • CEP special section issue on Advanced Fault Diagnosis for Sustainable
           Flight Control—The European ADDSAFE Project
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Andreas Varga , Philippe Goupil , Andrés Marcos



      PubDate: 2014-09-05T00:08:42Z
       
  • A multi-agent architecture for diagnosing simultaneous faults along water
           canals
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): João Lemos Nabais , Luís F. Mendonça , Miguel Ayala Botto
      Water is intensively used in mankind activities, in particular in agriculture. Water is commonly conveyed for agriculture purposes through water canal networks which are large-scale spatially distributed systems crossing extensive regions. In the presence of leaks, unauthorized water withdrawals, water depth sensor faults or gate faults, the quality of service can be severely compromised. A system able to diagnose which type of fault is present at a given time is of vital importance to access the current state of the water canal and proceed to restore its nominal condition. This paper proposes a multi-agent architecture to simultaneously detect, isolate and estimate lateral outflows (e.g., leaks or water withdrawals) and hardware faults (e.g., a gate obstruction or a downstream water depth sensor fault) in water canal networks. First, the main canal network is broken down into several subsystems composed of a single canal pool with the corresponding gate. Then, an agent is assigned to each subsystem aiming at its fault diagnosis. The approach is based on the generation and evaluation of residuals obtained from the comparison of model-based output signals with real data. Application to an experimental water canal bears out the proposed architecture as a valuable tool for monitoring and supervising general water canals.


      PubDate: 2014-09-05T00:08:42Z
       
  • IFC - Editorial Board / Funding body / agreements policies
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31




      PubDate: 2014-09-05T00:08:42Z
       
  • Editorial for the special section of the 8th IFAC SAFEPROCESS 2012
           Symposium
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Cristina Verde R.



      PubDate: 2014-09-05T00:08:42Z
       
  • Second order sliding mode observers for the ADDSAFE actuator benchmark
           problem
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Halim Alwi , Christopher Edwards
      This paper presents the evaluation process and results associated with two different fault detection and diagnosis (FDD) schemes applied to two different aircraft actuator fault benchmark problems. Although the schemes are different and bespoke for the problem being addressed, both are based on the concept of a second order sliding mode. Furthermore both designs are considered as ‘local’ in the sense that a localized actuator model is used together with local sensor measurements. The schemes do not involve the global aircraft equations of motion, and therefore have low order. The first FDD scheme is associated with the detection of oscillatory failure cases (OFC), while the second scheme is aimed at the detection of actuator jams/runaways. For the OFC benchmark problem, the idea is to estimate the OFC using a mathematical model of the actuator in which the rod speed is estimated using an adaptive second order exact differentiator. For the jam/runaway actuator benchmark problem, a more classical sliding mode observer based FDD scheme is considered in which the fault reconstruction is obtained from the equivalent output error injection signals associated with a second order sliding mode structure. The results presented in this paper summarize the design process from tuning, testing and finally industrial evaluation as part of the ADDSAFE project.


      PubDate: 2014-09-05T00:08:42Z
       
  • Hybrid predictive control of a coaxial aerial robot for physical
           interaction through contact
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Kostas Alexis , Christoph Huerzeler , Roland Siegwart
      This paper deals with the control of an unmanned coaxial helicopter designed towards active physical interaction with its environment. The system design is tailored to robust interaction through contact (e.g. docking and sliding on walls). Due to the rapid change of the dynamics from free-flight to the helicopter subject to the contact forces, a hybrid model is developed. This model captures all modes of the vehicle dynamics and is the basis for the design of a hybrid model predictive control strategy that ensures the stability of the hybrid dynamics and provides optimal maneuvering, docking on walls as well as sliding on them. The proposed control law is evaluated through experimental studies.
      Graphical abstract image Highlights

      PubDate: 2014-09-05T00:08:42Z
       
  • An application of adaptive techniques to vibration rejection in adaptive
           optics systems
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Riccardo Muradore , Lorenzo Pettazzi , Richard Clare , Enrico Fedrigo
      In modern Adaptive Optics (AO) systems, lightly damped sinusoidal oscillations resulting from telescope structural vibrations have a significant deleterious impact on the quality of the image collected at the detector plane. These oscillations can be observed in any mode of a generic modal representation of the AO wave-front sensor. A technique for the rejection of periodic disturbances recently presented in the literature has been adapted to the problem of rejecting vibrations in AO loops. The proposed methodology aims at estimating the harmonic disturbance together with the response of the plant at the vibration frequency. The algorithm has been tested in simulation on realistic scenarios and at the telescope.


      PubDate: 2014-09-05T00:08:42Z
       
  • Online detection of time-variant oscillations based on improved ITD
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Zixu Guo , Lei Xie , Taihang Ye , Alexander Horch
      An online detector for time-variant oscillations in univariate time-series is proposed. This paper is motivated by the fact that it is still an open problem to design a real-time oscillation detector which is applicable to non-linear, non-stationary and intermittent oscillations. The proposed procedure is based on intrinsic time-scale decomposition (ITD) and contains (i) an improved iteration termination condition for ITD with on-line back-redecomposition and (ii) a novel hypothesis test with a robust statistic of variation coefficient which enables online monitoring of time-variant oscillations. The proposed approach is computationally efficient, does not require a priori supervision window and is better applicable for online detection of time-variant oscillations. In addition, it preserves nonlinear features in process variables which facilitates subsequent oscillation diagnosis. Simulation examples and industrial applications are provided to demonstrate the effectiveness of the proposed online oscillation detector.


      PubDate: 2014-09-05T00:08:42Z
       
  • Multiobjective model predictive control for dynamic pickup and delivery
           problems
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Alfredo Núñez , Cristián E. Cortés , Doris Sáez , Bart De Schutter , Michel Gendreau
      A multiobjective-model-based predictive control approach is proposed to solve a dynamic pickup and delivery problem in the context of a potential dial-a-ride service implementation. A dynamic objective function including two relevant dimensions, user and operator costs, is considered. Because these two components typically have opposing goals, the problem is formulated and solved using multiobjective model predictive control to provide the dispatcher with a more transparent tool for his/her decision-making process. An illustrative experiment is presented to demonstrate the potential benefits in terms of the operator cost and quality of service perceived by the users.


      PubDate: 2014-09-05T00:08:42Z
       
  • Nonlinear model reference adaptive impedance control for human–robot
           interactions
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Mojtaba Sharifi , Saeed Behzadipour , Gholamreza Vossoughi
      Four nonlinear Model Reference Adaptive Impedance Controllers are introduced, tested, and compared for the control of the robot impedance with uncertainties in model parameters. The intended application area is human–robot interactions (HRI), particularly rehabilitation robots and haptic interfaces. All of the controllers make the closed-loop dynamics of the robot similar to the reference impedance model besides providing asymptotic tracking of the impedance model for the robot end-effector in Cartesian coordinates. The tracking and global stability are proved using Lyapunov stability theorem. Based on the simulations and experiments on a two-DOFs robot, the effectiveness of the proposed controllers is investigated.


      PubDate: 2014-08-18T22:32:21Z
       
  • Vision-based target tracking with a small UAV: Optimization-based control
           strategies
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Steven A.P. Quintero , João P. Hespanha
      This paper considers the problem of a small, fixed-wing UAV equipped with a gimbaled camera autonomously tracking an unpredictable moving ground vehicle. Thus, the UAV must maintain close proximity to the ground target and simultaneously keep the target in its camera׳s visibility region. To achieve this objective robustly, two novel optimization-based control strategies are developed. The first assumes an evasive target motion while the second assumes a stochastic target motion. The resulting optimal control policies have been successfully flight tested, thereby demonstrating the efficacy of both approaches in a real-world implementation and highlighting the advantages of one approach over the other.


      PubDate: 2014-08-18T22:32:21Z
       
  • A method for detecting non-stationary oscillations in process plants
    • Abstract: Publication date: November 2014
      Source:Control Engineering Practice, Volume 32
      Author(s): Vesa-Matti Tikkala , Alexey Zakharov , Sirkka-Liisa Jämsä-Jounela
      Persistent oscillations are a common problem in process plants since they cause excessive variation in process variables and may compromise the product quality. This paper proposes a method for detecting oscillations in non-stationary time series based on the statistical properties of zero-crossings. The main development presented is a technique to remove a non-stationary trend component from a signal before applying an oscillation detection procedure. The properties and performance of the method are analyzed using simulation experiments, a comparative study using industrial benchmark data, and tests with paperboard machine data. Finally, the simulation and industrial results are analyzed and discussed.


      PubDate: 2014-08-14T22:21:33Z
       
  • Iterative learning control for robotic-assisted upper limb stroke
           rehabilitation in the presence of muscle fatigue
    • Abstract: Publication date: Available online 5 August 2014
      Source:Control Engineering Practice
      Author(s): Wenkang Xu , Bing Chu , Eric Rogers
      The use of iterative learning control to regulate assistive functional electrical stimulation applied to the muscles of patients undergoing robotic-assisted upper limb stroke rehabilitation has been followed through small scale clinical trials. These trials confirmed that an increase in patient ability to complete the specified task also led to a reduction in the level of electrical stimulation required. This previous work assumed that the effects of muscle fatigue could be neglected but if a patient suffers fatigue during a rehabilitation session then their the session goals are not achieved or, more likely, the session must be abandoned due to the time limits imposed by the ethical approval required to conduct such sessions. In this paper the results of the first investigation into enhancing the control scheme to remove or lessen the effects of fatigue and hence make better use of the time available for a session are given. The scheme considered adds a feedback loop around the muscle model used, where the performance results given are based on a model for the dynamics constructed using patient data collected in previous clinical trials.


      PubDate: 2014-08-05T21:53:08Z
       
  • Modelling and control of an assembly/disassembly mechatronics line served
           by mobile robot with manipulator
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Eugenia Minca , Adrian Filipescu , Alina Voda
      The aim of this paper is to reverse an assembly line using a mobile platform equipped with a manipulator. By reversibility we mean that the line is able to perform disassembly. For this purpose, an assembly/disassembly line balancing (A/DLB) and a synchronised hybrid Petri nets (SHPN) model will be used to model and control an assembly/disassembly mechatronics line (A/DML), with a fixed number of workstations, served by a wheeled mobile robot (WMR) equipped with a robotic manipulator (RM). The SHPN model is a hybrid type, where A/DML is the discrete part, and WMR with RM is the continuous part. Moreover, the model operates in synchronised mode with signals from sensors. Disassembly starts after the assembly process and after the assembled piece fails the quality test, in order to recover the parts. The WMR with RM is used only during disassembly, to transport the parts from the disassembling locations to the storage locations. Using these models and a LabView platform, a real-time control structure has been designed and implemented, allowing automated assembly and disassembly, where the latter is assisted by a mobile platform equipped with a manipulator.
      Graphical abstract image

      PubDate: 2014-07-27T21:06:02Z
       
  • Automated synthesis of hybrid Petri net models for robotic cells in the
           aircraft industry
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Francesco Basile , Fabrizio Caccavale , Pasquale Chiacchio , Jolanda Coppola , Alessandro Marino , Diego Gerbasio
      The use of robots in the aircraft structural assembly is a challenge. The presence of human operators, auxiliary systems and industrial robots makes hybrid the dynamic behavior of a robotic cell in this context. Here, the focus is on the automated synthesis of a model for the sequencing of the activities of a robotic cell in the aircraft industry. The cell model is obtained from a simple specification of resources and tasks, considered the main cell components, running the algorithm presented in this paper. The effectiveness of the model is shown using a case study defined by the ongoing European project LOCOMACHS (LOw COst Manufacturing and Assembly of Composite and Hybrid Structures, http://www.locomachs.eu/).


      PubDate: 2014-07-27T21:06:02Z
       
  • Active carbody roll control in railway vehicles using hydraulic actuation
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Edoardo F. Colombo , Egidio Di Gialleonardo , Alan Facchinetti , Stefano Bruni
      Carbody tilting is used in railway vehicles to reduce the exposure of passengers to lateral acceleration in curves, allowing these to be negotiated at higher speeds with the same level of comfort. This, however, requires a rather complex actuation system that increases vehicle weight and reduces space for passengers. This paper introduces a new concept that provides a limited amount of carbody tilt using hydraulic actuation. The device consists of interconnected hydraulic actuators attached to the carbody and bogies, replacing the passive anti-roll bar used in railway vehicles and in addition permitting active tilt control. Three control strategies for the active hydraulic suspension are proposed, and the regulator gains are defined using Genetic Algorithm optimisation, based on numerical simulation of the running behaviour of the actuated railway vehicle in a high-speed curve. Finally, the performance of the actuated vehicle is assessed on the basis of numerical simulations, showing it is possible to increase significantly the vehicle׳s running speed in fast curves compared with a vehicle equipped with passive suspension.


      PubDate: 2014-07-27T21:06:02Z
       
  • Quality prediction and analysis for large-scale processes based on
           multi-level principal component modeling strategy
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Zhiqiang Ge
      This paper proposed a multi-level principal component regression (PCR) modeling strategy for quality prediction and analysis of large-scale processes. Based on decomposition of the large data matrix, the first level PCR model divides the process into different sub-blocks through uncorrelated principal component directions, with a related index defined for determination of variables in each sub-block. In the second level, a PCR model is developed for local quality prediction in each sub-block. Subsequently, the third level PCR model is constructed to combine the local prediction results in different sub-blocks. For process analysis, a sub-block contribution index is defined to identify the critical-to-quality sub-blocks, based on which an inside sub-block contribution index is further defined for determination of the key variables in each sub-block. As a result, correlations between process variables and quality variables can be successfully constructed. A case study on Tennessee Eastman (TE) benchmark process is provided for performance evaluation.


      PubDate: 2014-07-27T21:06:02Z
       
  • An experimental assessment of finite-state Predictive Torque Control for
           electrical drives by considering different online-optimization methods
    • Abstract: Publication date: October 2014
      Source:Control Engineering Practice, Volume 31
      Author(s): Fengxiang Wang , Zhenbin Zhang , Alireza Davari , José Rodríguez , Ralph Kennel
      Finite-State Predictive Torque Control (FS-PTC) is experimentally investigated based on different online-optimization methods by using a two-level voltage source inverter for an induction machine. The calculation time and the switching frequencies are important research points for FS-PTC industrial applications. Long-step FS-PTC methods are expected to improve the performance of the system. However, the calculation time will increase exponentially with the increase of the prediction horizon. A reduced switching frequency PTC (RSF-PTC) method by considering the reductions of the switching frequency and the calculation time is tested. Based on this algorithm, an extended prediction horizon is proposed and verified on a common test bench. A torque-band based PTC (TB-PTC) method is proposed and discussed in this paper. The TB-PTC method pre-calculates the torque error between the predicted torque and the torque reference. The optimization method focuses on the flux error and the switching frequency for switching states which constrain the torque error within the torque-band. The conventional FS-PTC method, the RSF-PTC method with one-step and two-step horizons and the TB-PTC method are developed and experimentally compared in this work. The results confirm that conventional FS-PTC, RSF-PTC and TB-PTC methods can work well in the full speed range. When the switching frequencies and the calculation effort are taken into consideration, the RSF-PTC algorithm shows the better performance. However, the conventional FS-PTC method and the TB-PTC method have better current performance.


      PubDate: 2014-07-27T21:06:02Z
       
 
 
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