Control System In Order Research Articles

MODERNIZAÇÃO DO SISTEMA DE CONTROLE DA USTULAÇÃO NA VOTORANTIM METAIS

This paper discusses the modernization of the Zinc plant control system, implemented at Votorantim Metais, Juiz de Fora. Over a short period, a complete automation project was deployed, including development, commissioning, start up and assisted operation. The project’s requirements to migrate the existing platform included a new control system to increase plant’s robustness and reliability, as well as, a system capable of absorbing the remotes chassis already installed. It was adopted a unified supervision and control system in order to get a steady operation. The centralization of the maintenance and control activities, the agility in fault diagnosis and a reliable process database provided the operation and maintenance teams with a more detailed plant’s follow up and asset management. This way, allowing better planning of the Ustulation area. This was evidenced by the reduction of unplanned stoppages and increased process reliability.

The coordination of upper and lower arm rotation

We tested the hypothesis that the upper and lower arm act as a coordinative structure coupled through a higher order control system. Five healthy participants moved their hand between two targets in ten conditions via internal/external rotation of the shoulder. In eight conditions, the task required concurrent rotation of the lower arm (180 degrees pronation/supination). Movements were stereotypical within a condition but plotting the upper and lower arm angle against each other produced an asymmetrical pattern. With internal rotation, the upper arm reached peak angular velocity slower than the lower arm but this was reversed with external rotation. In two conditions, participants were asked to move faster and slower than their normal speed. The peak speed, time to peak speed and duration were predictable for the different tasks. Internal and external asymmetries decreased with faster movements. In addition a decrease in upper arm amplitude (from 90 degrees to 30 degrees) removed the asymmetry. The asymmetry was unaffected by initial posture but was exaggerated when external rotation was paired with pronation rather than supination, and internal rotation combined with supination (versus pronation). However, the presence of the same fundamental pattern suggests that the asymmetry is not due to biomechanical factors but might arise because of the difficulties involved in visually monitoring the hand when it is close to the body. The results support the idea that functional coupling can occur between upper and lower arm rotations and thus provides further evidence for a higher order control system which is responsible for coordination of arm segment movement.

Special issue on swarm robotics

Swarm robotics is a new approach to the coordination of multi-robot systems. In contrast with traditional multi-robot systems which use centralised or hierarchical control and communication systems in order to coordinate robots’ behaviours, swarm robotics adopts a decentralised approach in which the desired collective behaviours emerge from the local interactions between robots and their environment. Such emergent or self-organised collective behaviours are inspired by, and in some cases modelled on, the swarm intelligence observed in social insects. The potential for swarm robotics is considerable. Any task in which physically distributed objects need to be explored, surveyed, collected, harvested, rescued, or assembled into structures is a potential real-world application for swarm robotics. The key advantage of the swarm robotics approach is robustness, which manifests itself in a number of ways. Firstly, because a swarm of robots consists of a number of relatively simple and typically homogeneous robots, which are not pre-assigned to specific roles or tasks within the swarm, then the swarm can self-organise or dynamically re-organise the way individual robots are deployed. Secondly, and for the same reasons, the swarm approach is highly tolerant to the failure of individual robots. Thirdly, the fact that control is completely decentralised means that there is no common-mode failure point or vulnerability in the swarm. Indeed, it could be said that the high level of robustness evident in robotic swarms comes for free in the sense that it is intrinsic to the swarm robotics approach, which contrasts with the high engineering cost of fault tolerance in conventional robotic systems. The realisation of the potential of swarm robotics requires the solution of a number of very challenging problems. Firstly, in algorithm design: swarm roboticists face the problem of designing both the physical morphology and behaviours of the individual robots such that when those robots interact with each other and their environment, the desired overall collective behaviours will emerge. At present there are no principled approaches to the design of low-level behaviours for a given desired collective behaviour. Secondly, in implementation

Cortical activation during delay discounting in abstinent methamphetamine dependent individuals

Methamphetamine (MA)-dependent individuals prefer smaller immediate over larger delayed rewards in delay discounting (DD) tasks. Human and animal data implicate ventral (amygdala, ventral striatum, ventrolateral prefrontal cortex insula) and dorsal (dorsolateral prefrontal cortex, dorsal anterior cingulate cortex and posterior parietal cortex) systems in DD decisions. The ventral system is hypothesized to respond to the salience and immediacy of rewards while the dorsal system is implicated in the process of comparison and choice. We used functional Magnetic Resonance Imaging to probe the neural correlates of DD in 19 recently abstinent MA-dependent patients and 17 age- and gender-matched controls. Hard DD choices were associated with greatest activation in bilateral middle cingulate, posterior parietal cortex (PPC), and the right rostral insula. Control subjects showed more activation than MA patients bilaterally in the precuneus and in the right caudate nucleus, anterior cingulate cortex (ACC), and dorsolateral prefrontal cortex (DLPFC). Magnitude of discounting was correlated with activity in the amygdala, DLPFC, posterior cingulate cortex and PPC. Our findings were consistent with a model wherein dorsal cognitive systems modulate the neural response of ventral regions. Patients addicted to MA, who strongly prefer smaller immediate over larger delayed rewards, activate the dorsal cognitive control system in order to overcome their preference. Activation of the amygdala during choice of delayed rewards was associated with a greater degree of discounting, suggesting that heavily discounting MA-dependent individuals may be more responsive to the negative salience of delayed rewards than controls.

High dynamics control under voltage/current and harmonic constraints: SM-PMSM application for AC railways

The main objective of the proposed work is to perform stator flux and torque high dynamics response related to specific railway requirements such as anti-slid re-adhesion control. Moreover, this type of application takes into account DC bus voltage and current limitations. In addition, systems controlled by pulse width modulation (PWM) line side converters, injects harmonic current into the feeding overhead line. Therefore, it is necessary to consider an additional harmonic constraint (harmonic shape) as an entire part of the global control system in order not to interfere with signaling systems. Consequently, the high dynamics control objectives must be considered together with the PWM constraint and voltage/current limitations, as a single control task. Real-time simulation as well as experimental results for a specific railway test bench will be presented to highlight the performances of such control algorithm.

UAV Classical Flight Control Systems

Abstract:One of the attractive and challenging design problems is the Unmanned Air Vehicle (UAV) where theflight control system is designed to achieve robust stability and acceptable performance acrossspecified flight envelope in the presence of uncertainties. Therefore, this paper is devoted to designadequate automatic flight control systems in order to stabilize the attitudes and natural modes of aflying fixed wing (Aerosonde) UAV under exogenous disturbances. Toward this objective, a nonlinearmathematical model for the underlying aircraft is developed and linearized yielding a state-spacemodel. This linear model is then decoupled into two smaller models associated to the longitudinal andlateral motions of the aircraft. The natural modes for both motions are analyzed by initializing thesystem matrix with the real parts of eigenvector corresponding to each mode. Classical PID tuningtechniques have been utilized with the longitudinal model to design flight control systems that achievethe performance requirements; including good tracking and the rejection of disturbances.

Power output regularization in the active reproduction of sound fields in rooms

In this paper we address the problem of using a multi-channel active control system in order to reproduce a harmonic sound field in a large part of the volume of a reverberant room. The problems associated with the calculation of the inverse system matrix are confronted by introducing a term that is proportional to the sound power-output of the system in the cost function that is obtained by the multiple point method. Simulation results show that this technique results to a better conditioning of the system matrix at low frequencies, comparing to other traditional regularization techniques. Moreover, it is shown that this method can be employed to increase the spatial robustness of the control sensor array inside the listening room.

Nucleus accumbens is involved in human action monitoring: evidence from invasive electrophysiological recordings

The Nucleus accumbens (Nacc) has been proposed to act as a limbic-motor interface. Here, using invasive intraoperative recordings in an awake patient suffering from obsessive-compulsive disease (OCD), we demonstrate that its activity is modulated by the quality of performance of the subject in a choice reaction time task designed to tap action monitoring processes. Action monitoring, that is, error detection and correction, is thought to be supported by a system involving the dopaminergic midbrain, the basal ganglia, and the medial prefrontal cortex. In surface electrophysiological recordings, action monitoring is indexed by an error-related negativity (ERN) appearing time-locked to the erroneous responses and emanating from the medial frontal cortex. In preoperative scalp recordings the patient's ERN was found to be significantly increased compared to a large (n = 83) normal sample, suggesting enhanced action monitoring processes. Intraoperatively, error-related modulations were obtained from the Nacc but not from a site 5 mm above. Importantly, cross-correlation analysis showed that error-related activity in the Nacc preceded surface activity by 40 ms. We propose that the Nacc is involved in action monitoring, possibly by using error signals from the dopaminergic midbrain to adjust the relative impact of limbic and prefrontal inputs on frontal control systems in order to optimize goal-directed behavior.

Iterative Feedforward Tuning for Residual Vibration Reduction

An iterative approach for the determination of an input-output inversion feedforward control law for residual vibration reduction is proposed in this paper. In particular, point-to-point motion planning of vibratory servosystems is considered. The method aims at estimating recursively the parameters of the system in order to determine the exact command input to be applied to the control system in order to achieve a predefined motion without oscillations. In this context, a gradient based minimisation of the integrated square error cost function is performed. Simulation results show the effectiveness of the methodology.

Design Method of Fault Detector for Injection Unit

Abstract An injection unit is considered as a speed control system utilizing a reaction-force sensor. Our purpose is to design a fault detector that detects and isolates actuator and sensor faults given that the system is disturbed by a reaction force. First described is the fault detector's general structure. In this system, a disturbance observer that estimates the reaction force is designed for the speed control system in order to obtain the residual signals, and then post-filters that separate the specific frequency elements from the residual signals are applied in order to generate the decision signals. Next, we describe a fault detector designed specifically for a model of the injection unit. It is shown that the disturbance imposed on the decision variables can be made significantly small by appropriate adjustments to the observer bandwidth, and that most of the sensor faults and actuator faults can be detected and some of them can be isolated in the frequency domain by setting the frequency characteristics of the post-filters appropriately. Our result is verified by experiments for an actual injection unit.

The Monitoring and Control System of the LHCb Event Filter Farm

The LHCb experiment at CERN will have an on-line trigger farm composed of up to 2000 PCs. In order to monitor and control each PC and to supervise the overall status of the farm, a farm monitoring and control system (FMC) was developed. The FMC is based on distributed information management (DIM) system as network communication layer, it is accessible both through a command line interface and through the Prozeszligvisualisierungs und Steuerungssystem (PVSS) graphical interface, and it is interfaced to the finite state machine (FSM) of the LHCb experiment control system (ECS) in order to manage anomalous farm conditions. The FMC is an integral part of the ECS, which is in charge of monitoring and controlling all on-line components; it uses the same tools (DIM, PVSS, FSM, etc.) to guarantee its complete integration and a coherent look and feel throughout the whole control system.

Autonomous atmospheric entry on mars: Performance improvement using a novel adaptive control algorithm

Upcoming landing missions to Mars will require on-board guidance and control systems in order to meet the scientific requirement of landing safely within hundreds of meters to the target of interest. More specifically, in the longitudinal plane, the first objective of the entry guidance and control system is to bring the vehicle to its specified velocity at the specified altitude (as required for safe parachute deployment), while the second objective is to reach the target position in the longitudinal plane. This paper proposes an improvement to the robustness of the constant flight path angle guidance law for achieving the first objective. The improvement consists of combining this guidance law with a novel adaptive control scheme, derived from the so-called Simple Adaptive Control (SAC) technique. Monte-Carlo simulation results are shown to demonstrate the accuracy and the robustness of the proposed guidance and adaptive control system.

A Design Methodology for a Self-Oscillating Electronic Ballast

This paper presents a design methodology and analysis of electronic ballast employing the self-oscillating-command circuit. The self-oscillating electronic ballast is represented as a relay control system in order to determine its parameters using the describing-function method and an extended Nyquist stability criterion. Simulation and experimental results of the electronic ballast supplying a 40-W fluorescent lamp are presented in order to confirm the feasibility of the performed design methodology.

스마트 스페이스를 위한 난방, 환기 및 공기조화 시스템의 지능형 디지털 제어

This paper studies an automation problem of a heating, a ventilating, and an air conditioning (HVAC) for the development of smart space. The HVAC system is described by the fuzzy system for the stability analysis and the controller design. The linear matrix inequalities (LMIs) conditions are derived for the stabilization problem of the closed-loop system under the analog control. Also, it is required to digitally redesign the pre-designed the analog HVAC control system in order to accomplish the remote control via web. It is shown the this digital redesign problem can be converted to the convex optimization problem with the LMI constraints. An example is provided to show the effectiveness of the proposed method.

STRONG FEASIBILITY IN INPUT-MOVE-BLOCKING MODEL PREDICTIVE CONTROL

Time-invariant input-move-blocking regimes are used in many practical online model predictive control systems in order to reduce the computational complexity of the associated finite-horizon optimal control problem, and have been shown to be beneficial for offline model predictive control methods also. However, until now there exists no method to ensure strong feasibility. In this paper a least-restrictive method to enforce strong feasibility in time-invariant input-move-blocking model predictive control problems is proposed, where the state of the first prediction step is constrained to a novel type of controlled invariant set, called here a controlled invariant feasible set. An algorithm to determine maximal controlled invariant feasible sets is proposed. This algorithm is shown to be semi-decidable for the case of linear, time-invariant plants with time-invariant, polytopic state and control input constraint sets.

Vehicle dynamics with LMS Virtual.Lab Motion

LMS Virtual.Lab Motion is a complete and integrated solution to simulate realistic motion and loads of mechanical systems. It permits engineers to quickly analyse and optimize the real-world behavior of the mechanical design, before committing to expensive physical prototype testing. LMS Virtual.Lab Vehicle Motion simulates all types of vehicle ride and handling behavior from passenger cars and motor sport vehicles to multi-axle vehicles like trucks and buses. Through the multi-attribute nature of the LMS Virtual.Lab Solution, different vehicle performances can be balanced and optimized. This allows performing studies for example to improve the road noise while keeping the handling performance untouched. For handling analyses, LMS Virtual.Lab Motion Vehicle includes the possibility to quickly run standardized events. The industry driver ‘IPG-DRIVER’ is integrated in LMS Virtual.Lab Motion, which allows to simulate all the actions a human driver performs while driving a vehicle. The main tire models integrated in LMS Virtual.Lab Motion are the TNO Delft tire models (MF-Tyre and MF–SWIFT) and CDTire. Other tire models can be integrated using the Standard Tire Interface. The interface with Matlab/Simulink and LMS Imagine.Lab Amesim allows the integration of detailed models of electronic as well as hydraulic control systems in order to perform combined simulations to analyze for example the effect of active safety systems on the vehicle dynamics. As such, LMS Virtual.Lab Motion Vehicle provides a complete package to efficiently perform vehicle dynamics studies.

Broadband Robust Controller Design of Multi-Frequency-Band Parallel Control System

This paper proposes an approach on broadband robust controller design of multi-frequency-band parallel control system in order to achieve a significant vibration reduction in broadband frequency range. Mechanical systems usually have vibration and noise problems in various frequency ranges. A complex high-order modeling has to be conducted to control the vibration and noise in broadband frequency range. In this case, the modeling error is generally increased, resulting in a degradation of control performance. This study designs the multiple subcontrollers based on the multiple sub-models derived in the corresponding frequency ranges. The order of each sub-model becomes small and so the modeling accuracy is improved. The total controller is constructed as the parallel circuit with each sub-controller designed in each frequency range. Each sub-controller is designed to satisfy the closed-loop stability against the interference to other sub-controllers in thisstudy. It is verified that the calculation efficiency and control performance can be enhanced by the proposed control strategy.

2223 周波数帯域分離型並列コントローラによる広帯域ロバスト協調制御法(スマート構造システム同定・振動制御・診断)

This paper proposes an approach on broadband robust controller design of multi-frequency-band parallel control system in order to achieve a significant vibration reduction in broadband frequency range. Mechanical systems usually have vibration and noise problems in various frequency ranges. A complex high-order modeling has to be conducted to control the vibration and noise in broadband frequency range. In this case, the modeling error is generally increased, resulting in a degradation of control performance. This study designs the multiple sub-controllers based on the multiple sub-models derived in the corresponding frequency ranges. The order of each sub-model becomes small and so the modeling accuracy is improved. The total controller is constructed as the parallel circuit with each sub-controller designed in each frequency range. Each sub-controller is designed to satisfy the closed-loop stability against the interference to other sub-controllers in this study.

An Adaptive Variable Structure Control Law for Sensorless Induction Motors

This paper presents a new sensorless adaptive robust control for induction motor drives. The proposed design employs the so called vector (or field oriented) control theory for the induction motor drives and the designed control law is based on an integral sliding-mode algorithm that overcomes the system uncertainties. The proposed sliding-mode control law incorporates an adaptive switching gain that avoid calculating an upper limit of the system uncertainties. The design includes rotor speed estimation from measured stator terminal voltages and currents. The estimated speed is used as feedback in an indirect vector control system in order to achieve the speed control without the use of shaft mounted transducers. The stability analysis of the proposed controller under parameter uncertainties and load disturbances is provided using the Lyapunov stability theory. Finally simulated results show on the one hand that the proposed controller with the proposed observer provides high-performance dynamic characteristics, and on the other hand that this scheme is robust with respect to plant parameter variations and external load disturbances.

T-50 가로-방향축 비행제어법칙 설계 및 궤환이득의 변화에 따른 항공기 동특성에 관한 연구

The T-50 advanced trainer aircraft combines advanced aerodynamic features and a fly-by-wire flight control system in order to produce a stability and highly maneuverability. The flight control system both longitudinal and lateral-directional axes to achieve performance enhancements and improve stability. The T-50 employs the RSS concept in order to improve the aerodynamic performance in longitudinal axis and the longitudinal control laws employ the dynamic inversion with proportional-plus-integral control method. And, lateral-directional control laws employ the blended roll system both beta-betadot feedback and simple roll rate feedback with proportional control method in order to guarantee aircraft stability. This paper details the design process of developing lateral-directional control laws, utilizing the requirement of MIL-F-8785C and MIL-F-9490D. And, this paper propose the analysis of aircraft characteristics such as dutch-roll mode, roll mode, spiral mode, gain and phase margin about gains for lateral-directional inner loop feedback.