Application Of Control Strategy Research Articles

A Comparison between Two Simulation Models for Spread of Foot-and-Mouth Disease

Two widely used simulation models of foot-and-mouth disease (FMD) were used in order to compare the models’ predictions in term of disease spread, consequence, and the ranking of the applied control strategies, and to discuss the effect of the way disease spread is modeled on the predicted outcomes of each model. The DTU-DADS (version 0.100), and ISP (version 2.001.11) were used to simulate a hypothetical spread of FMD in Denmark. Actual herd type, movements, and location data in the period 1st October 2006 and 30th September 2007 was used. The models simulated the spread of FMD using 3 different control scenarios: 1) A basic scenario representing EU and Danish control strategies, 2) pre-emptive depopulation of susceptible herds within a 500 meters radius around the detected herds, and 3) suppressive vaccination of susceptible herds within a 1,000 meters radius around the detected herds. Depopulation and vaccination started 14 days following the detection of the first infected herd. Five thousand index herds were selected randomly, of which there were 1,000 cattle herds located in high density cattle areas and 1,000 in low density cattle areas, 1,000 swine herds located in high density swine areas and 1,000 in low density swine areas, and 1,000 sheep herds. Generally, DTU-DADS predicted larger, longer duration and costlier epidemics than ISP, except when epidemics started in cattle herds located in high density cattle areas. ISP supported suppressive vaccination rather than pre-emptive depopulation, while DTU-DADS was indifferent to the alternative control strategies. Nonetheless, the absolute differences between control strategies were small making the choice of control strategy during an outbreak to be most likely based on practical reasons.

Air-Path Model Predictive Control of a Heavy-Duty Diesel Engine with Variable Valve Actuation

In this paper, a model-based strategy for the air-path, fuel injection timing, and fuel pressure control of a heavy-duty Diesel engine is presented. The engine system is a six-cylinder Diesel engine, equipped with a dual-stage fixed geometry turbo system and a variable valve actuation (VVA) system. The VVA operates on the intake valves, and realizes a late Miller combustion cycle. The control strategy implemented is a multilinear - model predictive control (MPC), which manipulates the intake valve hold and closure timing, the fuel injection timing, and the needle opening pressure. The MPC objectives are: (i) to keep NOx emissions under a reference level, (ii) to keep the air-fuel ratio over a certain reference, while (iii) minimizing fuel consumption under other constraints. The use of a model predictive control strategy is motivated by the fact that the system is a multi-input multi-output system, with several constraints applied to it. This paper presents the applied control strategy and simulation results illustrating the potential of the proposed control. The simulation results show that the control strategy is applicable, and that the fuel consumption is minimized, but also that further refinements are required.

Analysis from robust control under environment constraint: application for traffic model

Traffic management solutions are increasingly called for to address problems of transport and mobility and nowadays, even to address the environmental impact. Traffic control uses strategies to reduce bottlenecks, travel time and costs. Although it is usually assumed that an improved traffic flow will result in lower vehicle emissions, little scientific research has been done concerning the effects of traffic control on emissions. Moreover, because changes in traffic flow do not necessarily influence travel times, noise and air quality in the same way, there is a clear need for a combined approach. The main idea was to apply control strategy on the road under the assumption of ensuring fluid traffic flow. In the following the gas emissions were evaluated as results of this regulation procedure. The proposed control approach is based on non-integer robust methodology. The chosen study case is a macroscopic traffic flow model.

Teaching Model Predictive Control Algorithm Using Starter Kit Robot

AbstractAdvanced control concepts present a teaching challenge, where even at master level students benefit from these concepts being implemented and demonstrated on real hardware, rather than simply modelling the plant, applying control strategy and tuning. This paper describes one of a series of three experiments demonstrating the implementation of different control strategies using adaptive cruise control (ACC) on robot models and real robots. The experiment described here utilises the model predictive control (MPC) strategy implemented in ACC. The algorithm is realised using the graphical programming language (LabVIEW) as the design environment and National Instruments Robotics Starter Kit robot as the target hardware, with the code being deployed on a field programmable gate array (FPGA), included in the robot’s architecture.Two robotic vehicles, ‘the leader’ and ‘the follower’ are programmed to execute ACC: the velocity of the leader robot and the distance between the robots are augmented into the r...

A Positioning Mooring System Design for Barge Ship Based on PID Control Approach

This paper presents some experimental results about Position Mooring (PM) system applied to the barge ship. In PM operation, the station keeping in surge, sway of vessel is provided by the mooring system. In this paper, a system, consisting of a barge vessel and mooring lines, is mathematically modeled. The position and orientation of vessel is controlled by changing the tensions in the mooring lines. The PID control strategy is applied to evaluate the efficiency of proposed system. Experimental result which corresponds to the applied control strategy is presented and discussed.

Optimization of an atmospheric air volumetric central receiver system: Impact of solar multiple, storage capacity and control strategy

Portugal has a high potential for concentrated solar power and namely for atmospheric air volumetric central receiver systems (CRS). The solar multiple and storage capacity have a significant impact on the power plant levelized electricity cost (LEC) and their optimization and adequate control strategy can save significant capital for the investors. The optimized proposed volumetric central receiver system showed good performance and economical indicators.For Faro conditions, the best 4 MWe power plant configuration was obtained for a 1.25 solar multiple and a 2 h storage. Applying control strategy #1 (CS#1) the power plant LEC is 0.234 €/kWh with a capital investment (CAPEX) of € 22.3 million. The capital invested has an internal rate of return (IRR) of 9.8%, with a payback time of 14 years and a net present value (NPV) of € 7.9 million (considering an average annual inflation of 4%). In the case of better economical indicators, the power plant investment can have positive contours, with an NPV close to € 13 million (annual average inflation of 2%) and the payback shortened to 13 years.

Passivity Based Control of a Cart with Inverted Pendulum

This paper deals with passivity based control of a cart , which can moves on a skew plain. On the cart a non actuated pendulum is assembled. Therefore, the mechanical system is non-linear, one degree under actuated and instable. The equation of motion is derived by the method of Lagrange. The goal of the control strategy is to stabilize the cart and the upper position of the pendulum. The applied control strategy is called Interconnection Damping Assignment Passivity Based Control (IDA-PBC). This method allows a physical approach with a simple proof of stability having appropriate Lyapunov function on hand. The simple proof of stability is an advantage of this theory. However, the proof of stability is fulfilled, challenging partial differential equation have to be solved to get the control law. Measurements results are presented.

Optimal Control and Strategy of Operating Mechanism for Pumping Unit Intermittent Pumping

In this work a new perspective of pumping unit intermittent pumping intelligent control in strippers is presented. The strategy consists in associating economic situations and dynamometer cards analysis in a cascaded control. In the proposal, the widely applied control strategies based on dynamometer cards and downhole pressure modeling and the overall economic efficiency, since the development of pumping unit operation mechanism plays a vital role to ensure energy saving in low-volume wells. The simulation results are analyzed in order to evaluate the operational conditions propitiated by intermittent pumping control in actual operation.

Heat load patterns in district heating substations

Future smart energy grids will require more information exchange between interfaces in the energy system. One interface where dearth of information exists is in district heating substations, being the interfaces between the distribution network and the customer building heating systems. Previously, manual meter readings were collected once or a few times a year. Today, automatic meter readings are available resulting in low cost hourly meter reading data. In a district heating system, errors and deviations in customer substations propagates through the network to the heat supply plants. In order to reduce future customer and heat supplier costs, a demand appears for smart functions identifying errors and deviations in the substations. Hereby, also a research demand appears for defining normal and abnormal heat load patterns in customer substations. The main purpose with this article is to perform an introductory analysis of several high resolution measurements in order to provide valuable information about substations for creating future applications in smart heat grids. One year of hourly heat meter readings from 141 substations in two district heating networks were analysed. The connected customer buildings were classified into five different customer categories and four typical heat load patterns were identified. Two descriptive parameters, annual relative daily variation and annual relative seasonal variation, were defined from each 1year sequence for identifying normal and abnormal heat load patterns. The three major conclusions are associated both with the method used and the objects analysed. First, normal heat load patterns vary with applied control strategy, season, and customer category. Second, it is possible to identify obvious outliers compared to normal heat loads with the two descriptive parameters used in this initial analysis. Third, the developed method can probably be enhanced by redefining the customer categories by their indoor activities.

Synthetic jet actuation strategies for momentumless trailing edge wake

Periodic addition of momentum employing a Trailing Edge Synthetic Jet Actuation (TESJA) to control the wake of a blunt trailing edge plate was investigated experimentally at Reynolds number Reh=U∞h/ν=7200, based on the trailing edge thickness, h. A pair of synthetic jets were symmetrically placed at the model base. Two-component PIV measurements were reported for natural wake and actuated wakes under different actuation strategies namely asymmetric actuation, symmetric synchronous dual-actuation, and out-of-phase dual-actuation. A pair of synthetic jets were symmetrically placed at the model base. Two positions of the TESJA on the model base (peripheral or central position) were also studied and discussed. The forcing was applied at a frequency of 0.75 the natural vortex shedding frequency, while a high momentum addition coefficient of up to 24% was applied to balance the momentum deficit and to accomplish a near momentumless state. The measurements revealed that the application of TESJA reduced the extent of the separation bubble and redistributed energy among the Reynolds stresses. A perfect lock-in of vortex shedding in the wake was achieved. The actuation efficiency depended on both the applied control strategy and the actuators' positions. Forcing was found to be most effective in achieving a near momentumless state when applied at base model extremities (peripheral configuration) to permit the interaction of synthetic jet with the neighbouring shear layers and a large entrainment. The above strategies and positions led generally to three actuated wake states: (1) vortex pair shedding vectoring for asymmetric forcing, (2) symmetric vortex shedding under in-phase synchronous forcing, and (3) alternate vortex shedding with increased vorticity and turbulence, combined with a large momentum addition when out-of-phase forcing was applied.

Real-Time Models of Hybrid Electric Vehicle Powertrains

Hybrid electric powertrains are developed for reducing the fuel consumption and the emission of carbon dioxide. In order to support this aim, the applied control strategy can be improved by testing and developing the electronic control units by means of Hardware-in-the-Loop simulation. For the simulation, a corresponding real-time model of the powertrain is required. The development of the model is a time-consuming task due to the high dynamics and switching frequencies in the electrical subsystem, comprising the electric drives, inverter and battery and due to the various configurations of the mechanical subsystem, comprising the transmissions. In this contribution, a method for an efficient modeling of different transmission configurations for power-split systems and different types of inverter is presented. Besides the required real-time capability, the models consider the correct power flows and power losses. The presented approach is proven by means of simulation results.

Teaching Fuzzy Logic Control Based on a Robotic Implementation

Advanced control concepts present a teaching challenge - even at master level students benefit from these concepts being implemented and demonstrated on real hardware, rather than simply modeling the plant, applying control strategy and tuning. This paper provides reference materials (both theoretical and test results), to be used in control teaching and assessment using a laboratory experiment, with a real-time single board computer based robotic vehicle (National Instruments Robotics Starter Kit). This paper explores the practical implementation of the ACC system through use of a real-time single board computer based robotic vehicle (National Instruments Robotics Starter Kit). The ACC algorithm based on fuzzy PID control is deployed on a field programmable gate array (FPGA), included in the robot's architecture. This robotic vehicle is programmed using a graphical programming language (LabVIEW). A Kalman filter is used to estimate the unmeasured parameters while implementing the control algorithm in the hardware (the real robot). The results obtained are compared for the simulation model and the real robot, respectively. The experiment demonstrates clear correlation between theoretical expectations and real-life system performance and at the same time offers a novel idea how to deliver this advanced control concept in an applied and visual manner.

Modelling of aerodynamic flutter on a NACA 4412 airfoil with application to wind turbine blades

The study of aeroelastic phenomena on Wind Turbines (WTs) has become a very important issue when it comes to safety and economic considerations, as WTs tend towards gigantism and flexibility. At the Wind Energy Research Laboratory (WERL), several studies and papers have been conducted and published, all focusing on Computational Fluid Dynamics (CFD model) approaches to model and simulate different aeroelastic phenomena. Despite the very interesting results obtained, CFD is very costly and is difficult to use directly for control purposes, due to the consequent computational time. This paper describes a complementary lumped system approach to CFD to model flutter phenomenon. This model is based on a Matlab-Simulink model that integrates turbulence characteristics as well as characteristics of aerodynamic physics. From this model, we elaborate on flutter eigenmodes and eigenvalues in an aim to apply control strategies and relate the ANSYS-based CFD modelling to the lumped system.

Robust control of vehicle suspension with electrohydraulic actuator

This paper presents a study on robust control of vehicle electrohydraulic suspension with parameter uncertainties. The change of sprung mass and the variation of spring stiffness, damping coefficient, and actuator parameters are considered as parameter uncertainties and described by different methods. A robust controller is then designed for the uncertain vehicle suspension model to optimise its performances on ride comfort, suspension deflection, and road holding ability considering suspension and actuator parameter uncertainties and actuator saturation. The sufficient conditions for designing such a controller are derived as linear matrix inequalities (LMIs) which can be solved using standard software. Numerical simulations are used to validate the effectiveness of the proposed approach. It is confirmed by the simulation results that the applied control strategy performs better than the passive suspension regardless of the parameter uncertainties.

Real-time application of shunt active power filter dynamic compensation using real-time windows target

SUMMARY In this contribution, a control strategy in phase coordinates abc is proposed as the reference current generator to be used by the shunt active power filter (APF) compensation device. The development of the proposed reference current generator is described in detail. Its control design is kept simple, and transformation between different frameworks is not needed, thus allowing the control strategy to be applicable for both three-phase and single-phase electric systems maintaining theoretical and practical advantages. The proposed control strategy for the reference current generator is tested using Matlab/Simulink® with the incorporation of the Real-Time Workshop® for the simulation of the shunt APF compensation in real time. Based on the reported real-time application, it is possible to obtain simulation conditions that are close to the true real-time environment under study using only a single computer, giving accurate results with relatively low-cost hardware and providing a more complete evaluation of the applied control strategy. The dynamic behavior and performance of the shunt APF, using the proposed reference current calculator, have shown remarkable results. Copyright © 2012 John Wiley & Sons, Ltd.

Integrated mosquito larval source management reduces larval numbers in two highland villages in western Kenya.

BackgroundIn western Kenya, malaria remains one of the major health problems and its control remains an important public health measure. Malaria control is by either use of drugs to treat patients infected with malaria parasites or by controlling the vectors. Vector control may target the free living adult or aquatic (larval) stages of mosquito. The most commonly applied control strategies target indoor resting mosquitoes. However, because mosquitoes spend a considerable time in water, targeting the aquatic stages can complement well with existing adult control measures.MethodsLarval source management (LSM) of malaria vectors was examined in two villages i.e. Fort Ternan and Lunyerere, with the aim of testing strategies that can easily be accessed by the affected communities. Intervention strategies applied include environmental management through source reduction (drainage of canals, land levelling or by filling ditches with soil), habitat manipulation (by provision of shading from arrow root plant), application of Bacillus thuringiensis var israelensis (Bti) and the use of predatory fish, Gambusia affinis. The abundance of immature stages of Anopheles and Culex within intervention habitats was compared to that within non-intervention habitats.ResultsThe findings show that in Fort Ternan no significant differences were observed in the abundance of Anopheles early and late instars between intervention and non-intervention habitats. In Lunyerere, the abundance of Anopheles early instars was fifty five times more likely to be present within non-intervention habitats than in habitats under drainage. No differences in early instars abundance were observed between non-intervention and habitats applied with Bti. However, late instars had 89 % and 91 % chance of being sampled from non-intervention rather than habitats under drainage and those applied with Bti respectively.ConclusionMost of these interventions were applied in habitats that arose due to human activities. Involvement of community members in control programs would be beneficial in the long term once they understand the role they play in malaria transmission. Apart from the need for communities to be educated on their role in malaria transmission, there is a need to develop and test strategies that can easily be accessed and hence be used by the affected communities. The proposed LSM strategies target outdoor immature mosquitoes and hence can complement well with control measures that target indoor resting vectors. Therefore inclusion of LSM in Integrated Vector Management (IVM) program would be beneficial.

Synergistic control of joint angle variability: Influence of target shape

Reaching movements are often used to study the effectiveness of motor control processes with respect to the final position of arm and hand. Empirical evidence shows that different targets can be grasped with similar final position accuracy. However, movements that achieve similar accuracy at their final position may nevertheless be controlled differently. In particular, control strategies may differ in the control of the abundant degrees of freedom with respect to the task-specific costs. The objective of the present study was to investigate whether the applied control strategy was influenced by the shape of the target to be grasped. It was investigated whether mechanical constraints, imposed on final hand orientation or final hand position by the shape of the targets, affected the synergistic coordination of the kinematic degrees of freedom of the arm. Subjects were asked to grasp either a cylindrical or a spherical target, which imposed different constraints on final hand orientation and position. Besides temporal movement aspects, variability of the joint angles of the arm, as well as variability of hand orientation and hand position was analyzed over the whole time course of movement execution, using the uncontrolled manifold method. Overall movement duration differed between cylindrical and spherical target condition, due to differences in deceleration duration. Reaching movements towards the cylindrical target, which was more constraint in final hand orientation and position, took longer than movements towards the spherical target. Analysis further revealed that the degrees of freedom of the arm were synergistically coordinated to stabilize both hand orientation and hand position, when grasping either the spherical or the cylindrical target. This suggests that the applied control strategy in natural reaching movements can simultaneously account for multiple task constraints. The analysis further revealed that stabilization of hand orientation was stronger when reaching towards a cylindrical target, which imposed more constraints on final hand orientation. In contrast, hand position was more strongly stabilized in the spherical target shape condition, where stronger constraints on final hand position were applied. This suggests that different target shapes do influence the control strategy of reaching movements even though variability at movement end was not affected.

Modeling and Simulation of a Novel Hydraulic Disc Brake for Truck-Mounted Drilling Rig

Hydraulic disc brake is essential for meeting the requirements of safety and economic efficiency during drilling and work-over procedure. To address this need, we have developed a programmable logic controller controlled novel hydraulic disc brake system with capability to apply control strategy similar to anti-lock braking system for hoisting system of truck-mounted drilling rig. This paper is to investigate the complicated interaction between the work clamp and the hydraulic control system. So designers can use this model to decide which control strategies are more suitable for the disc brake. This is demonstrated by modeling the advanced hydraulic system and simulating influential factors on dynamic characteristics of hoisting system disc brake, with the application of the Advanced Modeling Environment for Simulations of Engineering Systems. The method of modeling and simulation provides a simple, effective approach to studying hydraulic disc brake for hoisting system.

Does a crouched leg posture enhance running stability and robustness?

Humans and birds both walk and run bipedally on compliant legs. However, differences in leg architecture may result in species-specific leg control strategies as indicated by the observed gait patterns. In this work, control strategies for stable running are derived based on a conceptual model and compared with experimental data on running humans and pheasants ( Phasianus colchicus). From a model perspective, running with compliant legs can be represented by the planar spring mass model and stabilized by applying swing leg control. Here, linear adaptations of the three leg parameters, leg angle, leg length and leg stiffness during late swing phase are assumed. Experimentally observed kinematic control parameters (leg rotation and leg length change) of human and avian running are compared, and interpreted within the context of this model, with specific focus on stability and robustness characteristics. The results suggest differences in stability characteristics and applied control strategies of human and avian running, which may relate to differences in leg posture (straight leg posture in humans, and crouched leg posture in birds). It has been suggested that crouched leg postures may improve stability. However, as the system of control strategies is overdetermined, our model findings suggest that a crouched leg posture does not necessarily enhance running stability. The model also predicts different leg stiffness adaptation rates for human and avian running, and suggests that a crouched avian leg posture, which is capable of both leg shortening and lengthening, allows for stable running without adjusting leg stiffness. In contrast, in straight-legged human running, the preparation of the ground contact seems to be more critical, requiring leg stiffness adjustment to remain stable. Finally, analysis of a simple robustness measure, the normalized maximum drop, suggests that the crouched leg posture may provide greater robustness to changes in terrain height.

Response of a planar solid oxide fuel cell to step load and inlet flow temperature changes

To explore the dynamic characteristics of the SOFC systems and to develop relevant control strategies, a previously developed steady state SOFC model is converted to a dynamic model. The model includes mass, momentum, thermal and electrochemical analysis, as well as the kinetic model of hydrocarbon reactions. Applying two control strategies i.e., cell constant fuel flow rate and constant fuel utilization during the transient time, the model is implemented to analyse the dynamic behaviour of a planar direct internal reforming (DIR) SOFC cell under several step-load changes. Transient response, resulting from an inlet temperature variation, is also investigated. The results show that the relaxation time is strongly related to the thermal behaviour of the cell and the applied control strategy. However, it is almost independent of the load variation magnitude.