Control system

In this work an optimized version of the field-mill sensor structure for atmospheric electric field measurements was presented. Both the mechanical structure and the electronic front-end, acquisition and control system are optimized in order to reduce the power consumption and to enhance the instrument metrological performance in term of sensitivity and frequency band. A solar power operated system was realized and tested. The developed system is also equipped with a GPS receiver, allowing data synchronization. This feature enables the implementation of a distributed measurement system for the monitoring of the atmospheric electric field.

To achieve desired accuracy, precision and surface roughness during laser-material removal process, monitoring and control of the process parameters related to laser, optics, workpiece material and its motion are required. Focus position, defined as a gap between the focusing lens and the surface of the sample workpiece, is one of the most critical process parameters, which determines the projection of the intensity of the laser beam on the surface to be ablated and therefore directly affects volume and geometry of the material removed and there by machining quality. In this paper, acoustic emission (AE) generated by laser-material interactions was statistically analyzed with respect to the variations in the focus position. The study involved on-line measurements of the AE signal from the laser-material interaction zone as a function of the focus position and the width of the machined trenches. Several basic statistical parameters, e.g. average amplitude, variance and power spectrum density were analyzed to select distinct informational parameters. Pattern recognition analysis of three informational parameters based on variances within frequency diapasons of 20-180, 180-300, and 300-500 kHz was used for reliable classification of the focus position and width of the machined trenches. The results provide important information for future development of on-line monitoring and control systems for laser-material removal process. Crown

Electric lighting is one of the major energy consuming items in many non-domestic buildings. Using appropriate energy-efficient light fittings with dimming controls and proper daylighting schemes can help reduce the electrical demand and contribute to visual comfort and green building development. This paper presents a study on the energy and lighting performances for energy-efficient fluorescent lamps associated with electronic ballasts and high frequency photoelectric dimming controls installed in a school building. Electricity expenditures and indoor illuminance levels for a workshop and a classroom employing high frequency dimming controls were analyzed. Simple prediction methods were used to illustrate the lighting savings. The findings provide the operational and performance information, which would be applicable to other spaces with similar building layouts and lighting schemes.

Inspection of loaded printed circuit boards (PCBs) using 3D laser striping range data is described. The work presented here is intended to assess the feasibility of using 3D depth data for robust identification of PCB defects. A knowledge-based control system interrogates a 2D CAD database for PCB layout information. Test strategies are then implemented with efficient multiresolution data capture. Inspection algorithms use 3D scene models to detect and interpret faults. This paper describes the implementation of the 3D ...

For many years the Fermilab physics program has been dominated by the superconducting Tevatron accelerator producing beams for many fixed target and the proton-antiproton colliding beam experiments CDF and D0. More recently, major experiments have used beam from intermediate accelerators. The MiniBooNE and MINOS experiments use 8 and 120 GeV beam respectively for neutrino oscillation studies. Several other experiments and test beams have also used 120 GeV beam. This paper describes the control system for the accelerator complex that was originally developed for the start of Tevatron operation in 1983. This system is common to all accelerators in the chain, and has been successfully evolved to accommodate new hardware, new software platforms, new accelerators, and increasingly complex modes of operation.

High penetration of renewable energy sources such as wind generation in microgrids (MGs) causes fluctuations of power flow and significantly affects the power system operation. This can lead to severe problems, such as system frequency oscillations, and/or violations of power lines capability. With the proper control, superconducting magnetic energy storage (SMES) is able to significantly enhance the dynamic security of the power system. In a SMES system, the power conditioning system (PCS) is the crucial component that directly influences the validity of the SMES in the dynamic control of the power system. This paper proposes the use of an improved SMES controller for the stabilization and control of the power flow of wind-hybrid MGs. In this sense, the design and implementation of a novel high performance PCS scheme of the SMES is described. Moreover, a detailed model of the SMES unit is derived and a novel three-level control scheme is designed, comprising a full decoupled current control strategy in the d-q reference frame and an enhanced power system frequency controller. The dynamic performance of the proposed systems is fully validated by computer simulation.

The Common Object Request Broker Architecture (CORBA) is a middleware specification for the development of interoperable, distributed object systems. Object technology is of extreme importance in complex control system development besides its progressive use in real-time systems. This paper tries to provide a general overview of the topics in distributed object systems, focusing on CORBA aspects that are critical for control systems engineering. Some sample applications are presented.

In this paper we propose digital control methods for steering real analytic controllable systems between arbitrary state configurations. The main idea is to achieve a multirate sampled procedure to perform motions in all the directions of controllability under piecewise constant controls. When it is applied to nonholonomic control systems without drift, the procedure simplifies. In particular, it results in exact steering on chained systems recently introduced in the motion planning literature. A classical example is reported.

We developed a series of balloon experiments parachuting a 1:1 scale mock-up of the Huygens probe from an altitude just over 30 km to simulate at planetary scale the ÿnal part of the descent of the probe through Titan's lower atmosphere. The terrestrial atmosphere represents a natural laboratory where most of the physical parameters meet quite well the bulk condition of Titan's environment, in terms of atmosphere composition, pressure and mean density ranges, though the temperature range will be far higher.

The intention of the NETLANDER mission is to establish for the first time a Network of stations on the surface of Mars. Four identical surface modules are equipped with science payloads dedicated to study the atmosphere and geosphere of Mars at four different landing locations spread over the two hemispheres. The mission duration will be one Martian year. The surface modules and their sensitive electronics compartments have to withstand a wide range of hostile conditions on Mars. Further constraints are given during flight, where heat can be exchanged only across small interfaces. The purpose of the NETLANDER thermal control system is to maintain the electronics and battery temperatures within a narrow band. Contrasting demands of reduced heat leaks and effective dump of surplus heat require new technologies and advanced design concepts to be satisfied under strict mass limits imposed. Recently, the first thermal test model with the original thermal equipment has been completed and tested. The model includes a high performance insulation combined with an innovative loop heat pipe system integrated into a one-to-one lander-structure. The paper describes the design and development activities as well as the ground test campaign performed in simulated Martian environment. (N. Schneider).

Abstract— This paper presents an adaptive control scheme for suppressing jitter in laser beams. The variable-order adaptive controller is based on an adaptive lattice filter that implicitly identifies the disturbance statistics from real-time sensor data. The multi-channel adaptive ...

This study attempts to investigate the interplay of uncertainty, structure and trust on the diffusion of a subset of management information systems, namely management accounting and control systems. The article suggests that under conditions of uncertainty, trust and structure are significantly associated with the success of the implementation process. On the other hand, the importance of trust and structure is less significant when the management accounting and control system is not perceived as threatening to organizational actors. The study draws on social network theory and proposes an agent based modeling approach to study the interplay of uncertainty, trust and structure on the diffusion process.

Construction project control aims to effectively obtain real-time information and enhance dynamic control by utilizing information sharing and connecting involved participants of the projects to reduce construction conflicts and project delays. However, extending the construction project control system to job sites is not considered efficient because using notebooks in a harsh environment like a construction site is not particularly a conventional practice. Meanwhile, paper-based documents of the site processes are ineffective and cannot get the quick response from the office and project control center. Integrating promising information technologies such as personal digital assistants (PDA), bar code scanning, and data entry mechanisms, can be extremely useful in improving the effectiveness and convenience of information flow in construction supply chain control systems. Bar code scanning is appropriate for several construction applications, providing cost savings through increased speed and accuracy of data entry. This article demonstrates the effectiveness of a bar-code-enabled PDA application, called the mobile construction supply chain management

Electronic throttle is a DC motor driven valve that regulates air inflow into the engine's combustion system. The goal of the throttle control system is twofold: to achieve fast and accurate valve plate angle reference tracking, and to preserve outwearing of the throttle by constraining physical variables to their normal-operation domains. These high quality control demands are hard to accomplish since the plant is burdened with a strong nonlinear effects of friction and limp-home nonlinearity. For the purpose of controller synthesis first a discrete-time piecewise affine model of the throttle was developed and then a time-optimal model predictive control problem was solved. We propose a procedure to model friction in a discrete-time piecewise affine form that is suitable for simulation and control. The optimal controller action computation can be restated as a mixed-integer program. However, due to the small sampling time, solving such a program on-line (in a receding horizon fashion) is very prohibitive. In this paper we use recent theoretical results that enable off-line pre-computation of the optimal control law in the form of a look-up table. The technique employs invariant set computation and reachability analysis using multi-parametric programming. Finally, we compare experimental results of our approach with the performance of a tuned PID controller coupled with a feedforward compensation of the nonlinearities. We achieve more than two times faster transients while preserving the quality regarding the absence of an overshoot and static accuracy within the measurement resolution.

Pulse-modulated converter systems play an important role in modern power electronics. Systems of this type also deserve considerable theoretical interest because of the complex interplay they exhibit between ordinary (smooth) bifurcations and so-called border-collision bifurcations generated by the switching dynamics. Particularly interesting are the unusual transitions to torus dynamics, i.e., to a mode of behavior in which the regular switching dynamics is modulated by another oscillatory mode that may arise through instability in the feedback control. Using the model of a two-level DC/DC converter as an example the paper provides a survey of three new mechanisms of torus bifurcation that can be observed in pulse-modulated control systems. The paper concludes with a discussion of the influence that operation in the torus regimes will have on the efficiency of the converter.

This paper aims to develop and validate an ANSYS finite element model to predict both the cured shape and snap-through of unsymmetric bistable laminates actuated by piezoelectric macro fibre composites attached to the laminate. To fully describe piezoelectric actuation the three dimensional compliance [s ij ], piezoelectric [d ij ] and relative permittivity [ε ij ] matrices were formulated for the macro fibre actuator. The deflection of an actuated isotropic aluminium beam was then modelled and compared to experimental measurements to validate the data. The model was then extended to bistable laminates actuated using macro fibre composites. Model results were compared to experimental measurements of laminate profile (shape) and snap-through voltage. The modelling approach is an important intermediate step toward enabling design of shape-changing structures based on bistable laminates.

Introduction The purpose of this paper is to serve as an introduction to neural networks and to sug-gest that neural network architecture can be used for design and application of intelligent control systems [ 11. The neural network ap-proach is introduced by defining the problem ...

This paper analyses control computation latency and jitter, which have been largely ignored in the control community for real-time (RT) control. The focus is on RT control systems with multiple control tasks running on a uniprocessor. Three strategies are proposed to reduce control latency and/or jitter: introduction of offsets into control task scheduling, decomposition of control tasks; and increasing the priority levels of output subtasks. Examples are given to demonstrate the effectiveness of the proposed methods.

Model-based design (MBD) involves designing a model of a control system, simulating and debugging it with dedicated tools, and finally generating automatically code corresponding to this model. In the domain of embedded systems, it offers the huge advantage of avoiding the timeconsuming and error-prone final coding phase. The main issue raised by MBD is the faithfulness of the generated code with respect to the initial model, the latter being defined by the simulation semantics. To bridge the gap between the high-level model and the low-level implementation, we use the synchronous programming language Lustre as an intermediate formal model. Concretely, starting from a highlevel model specified in the de-facto standard Simulink, we first generate Lustre code along with some structured "glue code", and then we generate embedded real-time code for the Xenomai RTOS. Thanks to Lustre's clean mathematical semantics, we are able to guarantee the faithfulness of the generated multi-tasked real-time code.

This paper describes the concepts that must be considered in order to achieve a flexible manufacturing system that allows the introduction of new products and new resources without an extensive reprogranming of the control system. In contrast to most other approaches a bottom-up design is attempted. A control software structure based on gen¢~ic resource models and the basic structure of a resource capability model are presented. A description of how to manufacture the products is also essential. Basic guidelines for a product model are given. Control algorithm aspects are discussed. Operator interface and system dependability are given consideration. Finally, a machining cell, used as a case study, is described.

The purpose of the paper is to illustrate the remote control of hardware in the laboratory for educational purposes, using commercial off-the-shelf equipment and available freeware. The goal is to eliminate extensive programming using high-level languages, such as Java programming to achieve remote connectivity, and focus on the primary task of implementing control algorithms. The use of MS NetMeeting for Internet-based control is described. Control experiments were easily carried out by a remote user, using Matlab-based real-time tools and MS NetMeeting.

This paper proposes several speech technology improvements for increasing robustness, reliability and ergonomics in speech interfaces for controlling aerial vehicles. These improvements consist of including a statistical language model for increasing the robustness against spontaneous speech, incorporating confidence measures for evaluating the performance of on-line the speech engines (better reliability), and a flexible response generation for improving the interface ergonomics. This paper includes a detailed description of the speech control interface developed as a result of the collaboration between the GTH (Grupo de Tecnología del Habla or Speech Technology Group) at Universidad Politécnica de Madrid (UPM) and the company Boeing Research and Technology Europe under the contract No. 206/05. This interface includes modules that perform speech recognition, natural language understanding and response generation via a speech synthesizer. In the system evaluation, the final results reported a 96.4% Word Accuracy and a 92.2% Semantic Concept Accuracy. This paper also provides a state-of-art review of using Speech Technology for controlling aerial vehicles, comparing the main initiatives carried out. A significant conclusion of this work is that Speech Technology is now ready enough to be considered as a new modality (in parallel with traditional ones) for introducing high level commands while the controller is carrying out others actions when interacting with these control systems. In critical applications (such as this) the best performance of this technology is achieved when all the configuration possibilities of the speech engines are accessible and the speech interface is designed in collaboration with Speech Technology experts.

This work is aimed at looking into the flatness control of the crane detailing adopted mechanisms and approaches in order to be able to control this system and to solve problems encountered during its functioning. The control objective is the sway free transportation of the crane s load taking the commands of the crane operator into account. Based on the mathematical model linearizing and stabilizing control laws for the slewing and luffing motion are derived using the input/output linearization approach. The method allows for transportation of the payload to a selected point and ensures minimisation of its swings when the motion is finished. To achieve this goal a mathematical model of the control system of the displacement of the payload has been constructed. A theory of control which ensures swing free stop of the payload is presented. Selected results of numerical simulations are shown. At the end of this work, a comparative study between the real moving and the desired one has been presented.

Twelve individuals took part in an experiment which investigated the feasibility of using physiological sensors to apply a pacing mitigation strategy to help prevent cognitive-overload-induced performance declines. The participants performed tasks using a ...

This paper presents the implementation of a fully digital smart charging system for traction lead-acid batteries for Electric Vehicles (EV). The charger uses a fast charge strategy, through the combination of constant high current charge periods with pulsant current charge periods. This charge system takes into account the actual battery charge state as well as the battery record, referred to previous charges and discharges. To obtain this smart charging system, it is necessary to develop a fast battery charge control system, a power source and a battery data acquisition system to periodically store the most important battery parameters during the discharge process. The fast charging of electric vehicle batteries promises a technically feasible approach to increase customer acceptability of Electric Vehicles (EV), and its main objetive includes short recharge times, high charge efficiencies and improved battery cycle life. The aim of the present work is the development of a smart charging strategy integrated with a digital data acquisition system implemented with a XC40010E FPGA from Xilinx.

As of November 1999, you may electronically access NUREG-series publications and other NRC records at NRC's Public Electronic Reading Room at http://www.nrc.gov/reading-rm.html. Publicly released records include, to name a few, NUREG-series publications; Federal Register ...

The SOLEIL control system, namely TANGO, developed in collaboration with ESRF, is now mature and stable. TANGO has been also chosen now by several other laboratories. High-level control applications implemented in the control-room for the storage ring, the two transfer lines, and the booster will be described in this paper. Three kinds of tools for commissioning are used. First the generic TANGO tools (alarms, simple graphical control applications), which allow us to control in a simple way any TANGO Device Server. Secondly a Matlab Middle Layer (adapted from ALS and SPEAR3): Matlab is fully interconnected with TANGO; it is used primarily for writing physics control applications. Finally GlobalSCREEN, a commercial SCADA software devoted for building operation applications has been selected (panels for controlling or displaying setpoint, readback values, status of equipments). In addition an overview of the historical and shortterm databases developed in house will be given.

Formations of multi-agent systems, such as satellites and aircraft, require that individual agents satisfy their kinematic equations while constantly maintaining inter-agent constraints. In this paper, we develop a systematic framework for studying formations of multiagent systems. In particular, we consider undirected formations for centralized formations and directed formations for decentralized formations. In each case, we determine differential geometric conditions that guarantee formation feasibility given the individual agent kinematics. Our framework also enables us to extract a smaller control system that describes the formation kinematics while maintaining all formation constraints.

Effective solutions for asset management become increasingly important in modern automation and control systems. They are especially required in the area of process control. The control systems used here usually consist of PLCbased networks, which are optimised concerning the special temporal and topological requirements of the process. Asset management functions have to be introduced to those systems, without any influence on the existing equipment. The paper shows an object-oriented solution based on PROFIBUS-PA device. By automatically evaluating a system structure and mapping the profile-relevant parameters of devices to proxy objects, different application modules for asset management functions can be implemented acting on these objects.

This paper presents a control strategy for the coordination of multiple mobile robots. A combination of the virtual structure and path following approaches is used to derive the formation architecture. A formation controller is proposed for the kinematic model of two-degree-of-freedom unicycle-type mobile robots. The approach is then extended to consider the formation controller by taking into account the physical

This paper presents the development of two multibody dynamics models to predict the whirl-flutter stability of a stiff-inplane tiltrotor wind-tunnel model and correlates the predictions with experimental data. Comprehensive, multibody-based dynamics analyses of rotorcraft enable modeling and simulation of the rotor system at a high level of detail so that complex mechanics and nonlinear effects associated with control system geometry and various types of hinges and joints are able to be considered. A parametric study of key design variables, such as control system stiffness, pitch-flap coupling, and aerodynamic compressibility was completed as part of this investigation, which may help to determine suitable design criteria for future stiff-inplane tiltrotor systems. Analytical results indicate consistent capabilities of multibody dynamics analyses in predicting the stiff-inplane tiltrotor whirl-flutter stability and show generally good agreement with the experimental results. Both analytical and experimental results show the destabilizing effects of pitch-flap coupling and aerodynamic compressibility on the whirl-flutter stability of a stiff-inplane tiltrotor whereas both results also indicate that a reduction in control system stiffness has little effect on whirl-flutter stability.

Robustness is pivot for robots operating in all-terrain environments. This demand comes mainly due to the highly heterogeneous and unstructured nature of the terrain. Two particular topics are sensitive to this problem: locomotion control and wheel odometry. A behaviour-based approach is proposed for the locomotion control system, whereas a heuristic exploiting the kinematic and dynamical constraints of the robot is used to enhance wheel odometry accuracy. Experimental results on the Ares robot, which is a 1.5 m 2 vehicle with four independently steered wheels, show the ability of the proposed methods to cope with all-terrain environments. In addition, the modules for localisation, mapping, and obstacle avoidance are also addressed in order to provide a global perspective over the Ares robot's control system. 4

Agile and flexible manufacturing systems make it mandatory that control programs have features such as agility, flexibility and reusability to meet fast changing, customer demands. To cope with this, a task-oriented model of the control system provides control code, data mapping and generating PLC code according to assembly sequences. The model is defined with the unit functions which can describe

A block course of 12 days is described. It is considered to be appropriate for both physiologically naive and sophisticated students entering either a traditional or a problem-based curriculum. It is adaptable for medical schools in both developed and developing countries. Six problem-based small-group sessions, based on everyday human situations, are the core of the course. They are supplemented by a lecture series, laboratory experiments using student volunteers as subjects, laboratory demonstrations, and patient presentations. Student assessment is carried out by criterion-referenced examinations using take-home assignments, oral examinations, and a multiple-choice test containing context-dependent questions. The course is well received by students and faculty. Pre- and posttesting show that all students acquire a basic understanding of physiological control systems and of homeostatic mechanisms as they operate in intact human beings.

Significant progress has been made in the application of low plasticity burnishing (LPB) technology to military engine components, leading to orders of magnitude improvement in damage tolerance. Improved damage tolerance can facilitate inspection, reduce inspection frequency, and improve engine operating margins, all leading to improved military readiness at significantly reduced total costs. Basic understanding of the effects of the different LPB process parameters has evolved, and finite element based compressive residual stress distribution design methodologies have been developed. By incorporating accurate measurement of residual stresses to verify and validate processing, this combined technology leads to a total solutions approach to solve damage problems in engine components. An example of the total solution approach

Battery energy storage systems, comprising lead-acid batteries, power conversion systems, and control systems, are in commercial operation around the world. They are used by three main groups: power generating utilities; power distributing utilities; and major power consumers (such as electric furnace foundries). The principal advantages of battety energy storage systems to generating utilities include: load leveling: frequency control; spinning re-.\erve; modular construction; convenient siting; no emissions; and investment deferral for new generation and transmission equipment. Power distributing utilities and major power consumers can avoid costly demand changes by discharging their batteries Lit peak periods and then recharging with lowjer cost off-peak power (say, at night). Battery energy storage systems are most cost effective when designed for discharge periods qf less than 5 I!; other systems (for example, pumped water storage) are better Juited for longer discharges. It is estimated that by the year 2000 there will be a potential need for 4000 MW of' battery c'nergy storage. New construction of five plants totaling 100 MW is presently scheduled for completion by the Puerto Rico Electric Power Authority between 1992 and 1995.

Phase II of the ISAC radioactive beam facility adds a superconducting Linac and a second experimental hall to the existing accelerator [1]. This addition will increase the size of the EPICS based control system by approximately 50%. The upgrade is done in parallel with beam delivery in ISAC-I. The paper will describe the control system additions and focus on the enhancement and webbased integration of tools used by the controls group.

XACML is commonly used as a policy exchange mechanism, decision engines are available, and verification tools are under development. However, no support for legacy access control systems exists yet. To explore the feasibility to support legacy systems, we designed and implemented a mapping of the IBM R Tivoli R Access Manager policy language into XACML. Although the Tivoli Access Manager policy language, being ACL-based, is simpler in general, it turned out to be a non-trivial task to encode the interplay of the Tivoli Access Manager policy elements and decision logic within XACML. To achieve this task, we had to come up with a novel use of XACML features.

Electricity interruption gives rise to a complete disorder in the society and is therefore unappreciated and highly criticized. Consequently, it becomes a great concern for national and/or private energy companies to conduct their power systems under severe requirements. These companies are asked to ovoid failures that induce power oscillation, voltage drop and high frequency deviations because these phenomena can produce the loss of the system integrity by rapid voltage collapse or any transient stability mechanism. New technology alternatives such as FACTS (flexible alternative current transport systems) can positively support conventional control systems such as PSSs (power system stabilizer), AVRs (automatic voltage regulator) and TGs (turbine governor). But at the same time, it is to recognize that power system control becomes more complicate and requires suitable global strategies. The paper deals with this problem and aims to show that UPFC is a suitable device in particular ...

This paper illustrates a new approach to the problem of making a logical network resource configuration, adapt to customer utilisation. This is to be achieved through the use of distributed multi-agent based control techniques. The agents have goals derived from different quality metrics, which the network has to provide. In ATM networks a well designed Virtual Path Connection (VPC) overlay network tries to maximise the probability of being able to accommodate connection demand within the control plane for that particular time frame. We assume that there already exists a reasonable VPC route topology in operation. The distributed agent control architecture (Tele-MACS) describes how the coupling of planning agents with reactive agents can adapt the network resource configuration to comply with changes in user demand. The changes to the VPC route topology or capacity assignments are a requirement for the network to adapt to user behaviour and our control architecture demonstrates a mechanism for achieving the reconfigurations. The network scenario is considered a closed system, where the network operator has full control over the network elements, such as the routing tables and switching capabilities. We demonstrate our concepts with a focus on a core node ATM wide area network example, where the control system seeks to maintain network survivability and efficient use of bandwidth resources.

The aim of this experimental study was to reduce electric energy consumption in marble cutting operation. We designed a prototype circular saw block cutting machine for marble cutting experiments. Fully computer-controlled this experimental setup has a LabVIEW based data acquisition and control system. In this study, manual and automatic cutting experiments were performed for three natural rocks (Cankiri beige and Afyon white marble and Denizli travertine). In experiments, travel speed is kept fixed in manual mode as usual in industry. Travel speed is controlled in automatic mode during the cutting process. Travel speed is controlled depending on specific energy. It is observed that, if automatic cutting is performed, electric energy saving can be provided in all of three rocks. Though energy saving is provided in all of three rocks, the best energy saving is provided in Cankiri beige marble.