Desired Response Time Research Articles

Designs and Feasibility Assessments of an Integrated Linear Electromagnetic Actuator for Cold Roll Mill Applications

This paper will present the detailed design and feasibility assessments of a linear electromagnetic actuator for providing the required roll-gap adjustment forces directly. A systematic analyzing scheme will be developed to optimize the system structures within specified physical constraints and steady-state operational requirements. The magnetic fluxes and thrusts that can be provided by the proposed system will be analyzed in detail, and the installation comparisons with those rotary electromagnetic counterparts will be discussed. By considering the desired system response times, the corresponding dynamic operational performances are also investigated. From these investigations, the technical feasibilities of adopting such electromagnetic systems for those commonly used hydraulic cylinder/servo valve compositions in the tandem roll mill can then be confirmed.

Design of a diagnostic residual gas analyzer for the ITER divertor

One of the ITER diagnostics having reached an advanced design stage is a diagnostic RGA for the divertor, i.e. residual gas analysis system for the ITER divertor, which is intended to sample the divertor pumping duct region during the plasma pulse and to have a response time compatible with plasma particle and impurity lifetimes in the divertor region. Main emphasis is placed on helium (He) concentration in the ducts, as well as the relative concentration between the hydrogen isotopes (mainly in the form of diatomic molecules of H, D, and T). Measurement of the concentration of radiative gases, such as neon (Ne) and nitrogen (N2), is also intended. Numerical modeling of the gas flow from the sampled region to the cluster of analysis sensors, through a long (∼8m long, ∼110mm diameter) sampling pipe originating from a pressure reducing orifice, confirm that the desired response time (∼1s for He or D2) is achieved with the present design.

FPGA implementation of current-sharing strategy for parallel-connected SEPICs

The attempt echoes to evolve an equal current-sharing algorithm over a number of single-ended primary inductance converters connected in parallel. The methodology involves the development of state-space model to predict the condition for the existence of a stable equilibrium portrait. It acquires the role of a variable structure controller to guide the trajectory, with a view to circumvent the circuit non-linearities and arrive at a stable performance through a preferred operating range. The design elicits an acceptable servo and regulatory characteristics, the desired time response and ensures regulation of the load voltage. The simulation results validated through a field programmable gate array-based prototype serves to illustrate its suitability for present-day applications.

Design and implementation of fractional order pole placement controller to control the magnetic flux in Damavand tokamak.

In this paper, a routine algorithm is presented to design a fractional order controller for tracking the reference model. Using this algorithm, a pole placement controller can be designed by assigning the desired integer and fractional order closed loop transfer functions. Considering the desired time response and using the generalized characteristic ratio assignment (CRA) method for fractional order systems and coefficient diagram method (CDM) for integer order systems, the desired closed loop system can be achieved. For various practical experiments, having the desired time responses is vital for magnetic flux in Damavand tokamak. To approach this, at first, the desired reference models are obtained based on CRA and CDM methods. After that, a fractional order pole placement controller is designed and simulated by this algorithm. At last, this controller is implemented on a digital signal processor to control the vertical magnetic flux of Damavand tokamak plant. The practical results show the satisfactory performance of the controller.

Optimal transient droop compensator and PID tuning for load frequency control in hydro power systems

Abstract This paper presents an optimal method to tune the Proportional, Integral and Derivative (PID) controller for a hydraulic turbine coupled with the corresponding Transient Droop Compensator (TDC). The proposed methodology is based on the Desired Time Response Specification (DTRS) of the input guide vane servomotor that includes typical rate limiters and gain saturation in power plants. Therefore, the problem consists of adjusting both the parameters of the controller and compensator such as the time response remains close to the specified one. To avoid suboptimal solutions at local minimum points, it is necessary to solve the resulting non linear problem in two steps: (i) firstly, solve a linear programming (LP) to determine the values of PID & TDC block using state space representation to match the input and output time responses specifications and (ii) determine the final values of the PID and TDC parameters using the previous results in a new non linear programming. The proposed methodology has presented the advantage of tuning the PID coordinated with the TDC spending low computational time. The results show that the performance of the method covers a wide range of operating conditions of the system. Comparisons were also made with existing methods in the literature to show the effectiveness of the proposed methodology.

Design of set-point weighting PIλ + Dμ controller for vertical magnetic flux controller in Damavand tokamak.

In this paper, a simple method is presented for tuning weighted PI(λ) + D(μ) controller parameters based on the pole placement controller of pseudo-second-order fractional systems. One of the advantages of this controller is capability of reducing the disturbance effects and improving response to input, simultaneously. In the following sections, the performance of this controller is evaluated experimentally to control the vertical magnetic flux in Damavand tokamak. For this work, at first a fractional order model is identified using output-error technique in time domain. For various practical experiments, having desired time responses for magnetic flux in Damavand tokamak, is vital. To approach this, at first the desired closed loop reference models are obtained based on generalized characteristic ratio assignment method in fractional order systems. After that, for the identified model, a set-point weighting PI(λ) + D(μ) controller is designed and simulated. Finally, this controller is implemented on digital signal processor control system of the plant to fast/slow control of magnetic flux. The practical results show appropriate performance of this controller.

Robust Stabilizing Controller Design for Inverted Pendulum System

In this paper the design of robust stabilizing state feedback controller for inverted pendulum system is presented. The Ant Colony Optimization (ACO) method is used to tune the state feedback gains subject to different proposed cost functions comprise of H-infinity constraints and time domain specifications. The steady state and dynamic characteristics of the proposed controller are investigated by simulations and experiments. The results show the effectiveness of the proposed controller which offers a satisfactory robustness and a desirable time response specifications. Finally, the robustness of the controller is tested in the presence of system uncertainties and disturbance.

A novel input shaping method based on system output

This paper proposes a novel input shaping method for under-damped systems. The most important advantage of this method is that only the signals of system outputs are required for the filter design. As the model information on the target system is not needed, the problem of parameter uncertainty is avoided. The designed filter can minimize the difference between the outputs of the actual system and the reference model. Simulation and experimental results showed that the resulting filters were not only able to effectively eliminate the vibrations in the system outputs, but also achieve the desired system response time. The robustness of the resulting filters against the parameters variation was also verified by simulation and experimental results.

A novel “Turn-On” fluorescent probe for F− detection in aqueous solution and its application in live-cell imaging

A novel probe incorporating quaternized 4-pyridinium group into a BODIPY molecule was synthesized and studied for the selective detection of fluoride ions (F−) in aqueous solution. The design was based on a fluoride-specific desilylation reaction and the “Turn-On” fluorescent response of probe 1 to F− was ascribed to the inhibition of photoinduced electron transfer (PET) process. The probe displayed many desired properties such as high specificity, appreciable solubility, desirable response time and low toxicity to mammalian cells. There was a good linearity between the fluorescence intensity and the concentrations of F− in the range of 0.1–1mM with a detection limit of 0.02mM. The sensing mechanism was confirmed by the NMR, electrospray ionization mass spectrum, optical spectroscopy and the mechanism of “Turn-On” fluorescent response was also determinated by a density functional theory (DFT) calculation using Gaussian 03 program. Moreover, the probe was successfully applied for the fluorescence imaging of F− in human epithelial lung cancer (A549) cells and alveolar type II (ATII) cells under physiological conditions.

Application of Active Suspension System to Reduce Aircraft Vibration using PID Technique and Bees Algorithm

dynamic load and vibration caused by landing impact and the unevenness of runway will result in airframe fatigue, discomfort of crew/passengers and the reduction of the pilot's ability to control the aircraft. The aim of the current paper is to design Proportional Integral Derivative classical controller based on Bees Intelligent Algorithm as the optimization technique for nonlinear model of active landing gear system that chooses damping and stiffness performance of suspension system at touchdown as optimization object. Optimal setting of controller parameters to achieve desirable time response using numerical software method based on Bees Algorithm is easier and more effective than other traditional methods because it does not need high experience and complex calculations and leads to better results. This research develops nonlinear two-dimensional mathematical model to describe landing gear system with oleo-pneumatic shock absorber and linear tire. Based on this model, the dynamic equations derived are used to investigate the behavior of an aircraft active landing gear system subject to runway disturbance excitation and the stability conditions of the landing system around static equilibrium position is studied according to the Routh-Hurwitz criterion. Simulink control system simulation software is utilized to validate the theoretical analysis of system stability and results comparison and adaptation of this paper with research of Wang and Xing about investigation of active landing gear system. Results of system numerical Simulation with optimized controller using Bees Algorithm in MATLAB software shows that the transmitted impact load to airframe, the vertical vibration of aircraft and time to return static equilibrium position at touchdown are significantly improved compared with other control performances.

Synthesis of Controllers for MIMO Systems with Time Response Specifications

This paper proposes the design of fixed low order controllers for Multi Input Multi Output (MIMO) decoupled systems. The simplified decoupling is used as a decoupling system technique due to its advantages compared to other decoupling methods. The main objective of the proposed controllers is to satisfy some desired closed loop step response performances such as the settling time and the overshoot. The controller design is formulated as an optimization problem which is non convex and it takes in account the desired closed loop performances. Therefore, classical methods used to solve the non convex optimization problem can generate a local solution and the resulting control law is not optimal. Thus, the thought is to use a global optimization method in order to obtain an optimal solution which will guarantee the desired time response specifications. In this work the Generalized Geometric Programming (GGP) is exploited as a global optimization method. The key idea of this method consists in transforming an optimization problem, initially, non convex to a convex one by some mathematical transformations. Simulation results and a comparison study between the presented approach and a Proportional Integral (PI) controller are given in order to shed light the efficiency of the proposed controllers.

On the control of a single flexible arm robot via Youla-Kucera parameterization

SUMMARYIn this paper, based on the Youla-Kucera (Y-K) parameterization, the control of a flexible beam acting as a flexible robotic manipulator is investigated. The method of Youla parameterization is the simple solution and proper method for describing the collection of all controllers that stabilize the closed-loop system. This collection comprises function of the Youla parameter which can be any proper transfer function that is stable. The main challenge in this approach is to obtain a Youla parameter with infinite dimension. This parameter is approximated by a subspace with finite dimensions, which makes the problem tractable. It is required to be generated from a finite number of bases within that space and the considered system can be approximated by an expansion of the orthonormal bases such as FIR, Laguerre, Kautz and generalized bases. To calculate the coefficients for each basis, it is necessary to define the problem in the form of an optimization problem that is solved by optimization techniques. The Linear Quadratic Regulator (LQR) optimization tool is employed in order to optimize the controller gains. The main aim in controller design is to merge the closed-loop system and the second order system with the desirable time response characteristic. The results of the Youla stabilizing controller for a planar flexible manipulator with lumped tip mass indicate that the proposed method is very efficient and robust for the time-continuous instances.

Efficient distributed skyline computation using dependency-based data partitioning

Skyline queries, together with other advanced query operators, are essential in order to help identify sets of interesting data points buried within huge amount of data readily available these days. A skyline query retrieves sets of non-dominated data points in a multi-dimensional dataset. As computing infrastructures become increasingly pervasive, connected by readily available network services, data storage and management have become inevitably more distributed. Under these distributed environments, designing efficient skyline querying with desirable quick response time and progressive returning of answers faces new challenges. To address this, in this paper, we propose a novel skyline query scheme termed MpSky. MpSky is based on a novel space partitioning scheme, employing the dependency relationships among data points on different servers. By grouping points of each server using dependencies, we are able to qualify a skyline point by only comparing it with data on dependent servers, and parallelize the skyline computation among non-dependent partitions that are from different servers or individual servers. By controlling the query propagation among partitions, we are able to generate skyline results progressively and prune partitions and points efficiently. Analytical and extensive simulation results show the effectiveness of the proposed scheme.

E2ARS : An Energy-Effective Adaptive Replication Strategy in Cloud Storage System

In order to solve the urgent issue of the energy consumption in the cloud storage system. An Energy-effective adaptive replication strategy (E 2 ARS) is proposed in this paper, in which data partition mechanism, minimal replicas determining model, replicas placement strategies and the adaptive gear-shifting mechanism are elaborately designed. We try to conserve the energy consumption while satisfying the users' desired response time by our E 2 ARS scheme. Mathematical analysis show that our E 2 ARS scheme will save energy consumption definitely when the system's workload is light or desir ed response time is loose. And the simulation experiment results demonstrate that through our E 2 ARS scheme energy consumption can be saved while with Qos satisfied and data availability

Algoritmo didáctico para la Asignación Implícita de Polos mediante la Especificación de Características Temporales deseadas usando Controladores PI Industriales

The aim of the work reported is the development of an algorithm for designing PI controllers with a didactic approach. This paper proposes a unified approach to guide the student step by step through the process of design and implementation of a controller in this class. Although PID control use in the industry is widespread, the fact is that the process of tuning the gains of these controllers in the industrial environment is empirical in most occasions. This article links naturally to controller design based on a desired time response with pole assignment process, which allows students to design controllers that are easily transferable to industrial control platforms and in particular programmable logic controllers (PLC , for its acronym in English). In applying the algorithm, students can observe how analytical design can succeed in the practical implementation, which would in principle to develop greater confidence in the design deterministic and metacognitive connections between the abstract and the real.

Dynamic analysis of cracks using the SGBEM for elastodynamics in the Laplace-space frequency domain

Abstract Dynamic analysis of a system can be carried out either in the time or frequency domains. Time responses/histories of this system may be directly obtained using time-domain formulations. In the frequency domain, analysis can be performed in either the Fourier or Laplace spaces. The symmetric-Galerkin boundary element method (SGBEM) for 2-D elastodynamics in the Fourier-space frequency domain has been previously reported in the literature. In this paper, the SGBEM for elastodynamics in the Laplace-space frequency domain using the standard continuous quadratic element and its application to dynamic analysis of cracks is presented for the first time. The technique developed is employed together with the fast Laplace inverse transform by Durbin to obtain time-dependent results for several typical examples including both crack and non-crack problems. These results are highly accurate when compared to those obtained from other numerical techniques. It is shown in this work that the very same boundary element code can be utilized to perform frequency domain analysis in either the Fourier or Laplace spaces. However, if time responses are required, the accuracy and computational effectiveness of the analysis may depend on the type of space selected as it determines the type of transforms (inverse Fourier/Laplace transforms) needed for converting frequency solutions to the desired time responses.

Perceptions of urgency: Defining the gap between what physicians and nurses perceive to be an urgent issue

IntroductionThrough our research into the design and evaluation of technology systems to improve the quality and safety of clinical communication, we have discovered that physicians and nurses differ in perspective regarding clinical prioritization and desirable response times. This has a number of important consequences including unnecessary interruptions, escalating conflict and deterioration in interprofessional relationships. Understanding the differing perspectives on clinical prioritization, or the gap in perceived urgency, may improve interprofessional relationships. MethodsWe conducted a mixed-methods study utilizing both qualitative (semi-structured interviews) and quantitative (surveys) methods to determine the gap between perceived urgency among physicians and nurses. The survey comprised of real messages extracted from the clinical communication system that was implemented. Physicians and nurses reviewed the messages and assigned an urgency level to each. The semi-structured interviews used open-ended questions to act as a guide to highlight key themes of interest. Thematic analysis, frequency tabulation, and triangulation were used to analyze the data. ResultsAlthough the surveys demonstrated concordance between physicians and nurses when independently ranking the urgency of clinical messages (kappa=0.66 SE 0.15), agreement was only fair in comparison to the urgency identified by the original nurse who sent the message (kappa=0.22 SE 0.18). We hypothesize that clinical context has a major role in defining urgency and may explain this finding. The survey data was triangulated with the semi-structured interview data and it was determined that the desired response time significantly impacted the sender's message prioritization. For example, shift changes and anxious family members were associated with discordant prioritizations. DiscussionThis study demonstrated that the perceived communication urgency gap between sending nurses and receiving physicians was primarily related to timeframe and context, not clinical condition. Most disagreement occurred when nurses used urgent messaging for time sensitive but not clinically urgent issues in an effort to expedite the resolution of their issue by the physicians. These results indicate the need for clinical communication systems to incorporate decision support around both clinical prioritization and expected response time in their design. Effective interprofessional communication is essential to the provision of safe, quality-based healthcare; these results highlight some of the sociotechnical aspects of health information technology implementation that must be considered.

Fuzzy Hardware: A Retrospective and Analysis

Worldwide, fuzzy systems are becoming a very useful mathematical tool to deal with nonlinear problems by inferring from a rule base that contains the necessary knowledge extracted from an expert. There are diverse forms to implement a fuzzy system depending on the desired response time, for which hardware implementations are best suited for high-speed demands. Fuzzy hardware has been exploited since the mid-1980s, and there have been many interesting architecture cases with different functional and performance characteristics that are reviewed in this paper from a categorical and historical point of view.

An adaptive energy-conserving strategy for parallel disk systems

Although various parallel disk systems have been developed to achieve high I/O performance and energy efficiency, most existing parallel disk systems lack an adaptive way to conserve energy in dynamically changing workload conditions. To solve this problem, we develop an adaptive energy-saving scheme or DCAPS in parallel disk systems. We show that adaptability in energy conservation can be achieved through the integration of a dynamic disk scheduling scheme and power management in parallel disk systems. DCAPS consists of a data partitioning mechanism, a response time estimator, and an adaptive energy-conserving mechanism. The Data partitioning mechanism allows DCAPS to adjust the parallelism degrees of write requests based on dynamic workload conditions. Apart from supporting the data partitioning mechanism, the response time estimator makes it possible for the adaptive energy-conserving mechanism to dynamically adjust voltage supply levels while guaranteeing desired response times. We conducted extensive experiments to quantitatively evaluate the performance of the proposed energy-conserving strategy. Experimental results consistently show that DCAPS significantly reduces energy consumption of parallel disk systems in a dynamic environment over the same disk systems without using DCAPS.

FPGA Implementation of Voltage Sharing Strategy for Series Connected SEPICS

paper orients to develop a strategy, with a view to ensure that the output voltage is equally shared among a number of Single Ended Primary Inductance Converters (SEPICs), in addition to ensuring regulation of the load voltage. It attempts to exploit the robustness of a Variable Structure Controller (VSC) to offset the circuit parasitic and extract a stable output irrespective of the variations in input voltage, circuit parameters and/or load. The methodology envisages characterizing the desired time response and acclaiming an acceptable steady state and transient results. It involves the use of a Field Programmable Gate Array (FPGA) to implement the proposed scheme and illustrate its practical viability. The performance evaluated through MATLAB based simulation is adequately validated using a suitable prototype to project its applicability over a preferred operating range.