Advances in PID Control

Since the foundation and up to the current state-of-the-art in control engineering, the problems of PID control steadily attract great attention of numerous researchers and remain inexhaustible source of new ideas for process of control system design and industrial applications. PID control effectiveness is usually caused by the nature of dynamical processes, conditioned that the majority of the industrial dynamical processes are well described by simple dynamic model of the first or second order. The efficacy of PID controllers vastly falls in case of complicated dynamics, nonlinearities, and varying parameters of the plant. This gives a pulse to further researches in the field of PID control. Consequently, the problems of advanced PID control system design methodologies, rules of adaptive PID control, self-tuning procedures, and particularly robustness and transient performance for nonlinear systems, still remain as the areas of the lively interests for many scientists and researchers at the present time. The recent research results presented in this book provide new ideas for improved performance of PID control applications

Adaptive Control

Adaptive control has been a remarkable field for industrial and academic research since 1950s. Since more and more adaptive algorithms are applied in various control applications, it is becoming very important for practical implementation. As it can be confirmed from the increasing number of conferences and journals on adaptive control topics, it is certain that the adaptive control is a significant guidance for technology development.The authors the chapters in this book are professionals in their areas and their recent research results are presented in this book which will also provide new ideas for improved performance of various control application problems

1st year EFAST annual report

The present report provides information about the activities conducted during the 1st year of the EFAST project. The first chapter is dedicated to describe the inquiries conducted at the beginning of the project and to briefly summarise the main results. The second chapter is dedicated to the first EFAST workshop where some of the leading scientists in the field of earthquake engineering have met to discuss about the need and the technologies related to earthquake engineering. The third chapter contains a state of the art and future direction in seismic testing and simulation. The final chapter is dedicated to describe the preliminary design of the web portal of the future testing facility.JRC.DG.G.5-European laboratory for structural assessmen

Development of U-model enhansed nonlinear systems

Nonlinear control system design has been widely recognised as a challenging issue where the key objective is to develop a general model prototype with conciseness, flexibility and manipulability, so that the designed control system can best match the required performance or specifications. As a generic systematic approach, U-model concept appeared in Prof. Quanmin Zhu’s Doctoral thesis, and U-model approach was firstly published in the journal paper titled with ‘U-model based pole placement for nonlinear plants’ in 2002.The U-model polynomial prototype precisely describes a wide range of smooth nonlinear polynomial models, defined as a controller output u(t-1) based time-varying polynomial models converted from the original nonlinear model. Within this equivalent U-model expression, the first study of U-model based pole placement controller design for nonlinear plants is a simple mapping exercise from ordinary linear and nonlinear difference equations to time-varying polynomials in terms of the plant input u(t-1). The U-model framework realised the concise and applicable design for nonlinear control system by using such linear polynomial control system design approaches.Since the first publication, the U-model methodology has progressed and evolved over the course of a decade. By using the U-model technique, researchers have proposed many different linear algorithms for the design of control systems for the nonlinear polynomial model including; adaptive control, internal control, sliding mode control, predictive control and neural network control. However, limited research has been concerned with the design and analysis of robust stability and performance of U-model based control systems.This project firstly proposes a suitable method to analyse the robust stability of the developed U-model based pole placement control systems against uncertainty. The parameter variation is bounded, thus the robust stability margin of the closed loop system can be determined by using LMI (Linear Matrix Inequality) based robust stability analysis procedure. U-block model is defined as an input output linear closed loop model with pole assignor converted from the U-model based control system. With the bridge of U-model approach, it connects the linear state space design approach with the nonlinear polynomial model. Therefore, LMI based linear robust controller design approaches are able to design enhanced robust control system within the U-block model structure.With such development, the first stage U-model methodology provides concise and flexible solutions for complex problems, where linear controller design methodologies are directly applied to nonlinear polynomial plant-based control system design. The next milestone work expands the U-model technique into state space control systems to establish the new framework, defined as the U-state space model, providing a generic prototype for the simplification of nonlinear state space design approaches.The U-state space model is first described as a controller output u(t-1) based time-varying state equations, which is equivalent to the original linear/nonlinear state space models after conversion. Then, a basic idea of corresponding U-state feedback control system design method is proposed based on the U-model principle. The linear state space feedback control design approach is employed to nonlinear plants described in state space realisation under U-state space structure. The desired state vectors defined as xd(t), are determined by closed loop performance (such as pole placement) or designer specifications (such as LQR). Then the desired state vectors substitute the desired state vectors into original state space equations (regarded as next time state variable xd(t) = x(t) ). Therefore, the controller output u(t-1) can be obtained from one of the roots of a root-solving iterative algorithm.A quad-rotor rotorcraft dynamic model and inverted pendulum system are introduced to verify the U-state space control system design approach for MIMO/SIMO system. The linear design approach is used to determine the closed loop state equation, then the controller output can be obtained from root solver. Numerical examples and case studies are employed in this study to demonstrate the effectiveness of the proposed methods

Industrial Chemistry Reactions: Kinetics, Mass Transfer and Industrial Reactor Design

Nowadays, the impressive progress of commercially available computers allows us to solve complicated mathematical problems in many scientific and technical fields. This revolution has reinvigorated all aspects of chemical engineering science. More sophisticated approaches to catalysis, kinetics, reactor design, and simulation have been developed thanks to the powerful calculation methods that have recently become available. It is well known that many chemical reactions are of great interest for industrial processes and must be conducted on a large scale in order to obtain needed information in thermodynamics, kinetics, and transport phenomena related to mass, energy, and momentum. For a reliable industrial-scale reactor design, all of this information must be employed in appropriate equations and mathematical models that allow for accurate and reliable simulations for scaling up purposes. The aim of this proposed Special Issue was to collect worldwide contributions from experts in the field of industrial reactor design based on kinetic and mass transfer studies. The following areas/sections were covered by the call for original papers: Kinetic studies on complex reaction schemes (multiphase systems); Kinetics and mass transfer in multifunctional reactors; Reactions in mass transfer-dominated regimes (fluid–solid and intraparticle diffusive limitations); Kinetic and mass transfer modeling using alternative approaches (ex. stochastic modeling); Simulations in pilot plants and industrial-sized reactors and scale-up studies based on kinetic studies (lab-to-plant approach)

A study to define meteorological uses and performance requirements for the Synchronous Earth Observatory Satellite

The potential meteorological uses of the Synchronous Earth Observatory Satellite (SEOS) were studied for detecting and predicting hazards to life, property, or the quality of the environment. Mesoscale meteorological phenonmena, and the observations requirements for SEOS are discussed along with the sensor parameters

Eulerian modelling and computational fluid dynamics simulation of mono and polydisperse fluidized suspension

This research project is concerned with the Eulerian-Eulerian mathematical modelling of fluidized suspensions. We first derive new averaged equations of motion for particulate systems made up of a finite number of monodisperse particle classes; this clarifies the mathematical origin and physical meaning of the terms featuring in the equations and allows to attain a well-posed multiphase model. We then tackle the closure problem of the fluid-particle interaction force in monodisperse fluidized suspensions, laying emphasis on the buoyancy, drag and elastic forces. We analyze critically several constitutive relations used to express these forces, we identify their shortcomings and we advance new, and more accurate, closure equations. To validate them we study, analytically and computationally, the expansion and collapse of homogeneous fluidized beds and their transition to the bubbling regime, comparing the result with experimental data. We then address the mathematical modelling of polydisperse fluidized suspensions, which are characterized by a continuous distribution of the particle properties, such as size or velocity. Here we adopt a more powerful modelling approach based on the generalized population balance equation (GPBE). Whereas the classical transport equations of continuum mechanics are three-dimensional, the GPBE is usually higher-dimensional and incompatible with customary computational schemes. To solve it, we use the method of moments (MOM), which resorts to a limited number of GPBE moments to derive three-dimensional transport equations that can be handled by normal CFD codes. The limited set of equations, which replaces the single multidimensional GPBE, keeps the problem tractable when applied to complicated multiphase flows; the main obstacle to the method is that the moment transport equations are mathematically unclosed. To overcome the problem, we present two very efficient methods, the direct quadrature method of moments (DQMOM) and the quadrature method of moments (QMOM). Both approximate the volume density function (VDF) featuring in the GPBE by using a quadrature formula. The methods are very flexible: the number of nodes in the quadrature corresponds to the number of disperse phases simulated. The more the nodes, the better the quadrature approximation; more nodes, however, entail also more complexity and more computational effort. For monovariate systems, i.e., systems with only one internal coordinate in the generalized sense, the methods are entirely equivalent from a theoretical standpoint; computationally, however, they differ substantially. To conclude the work, we use DQMOM to simulate the dynamics of two polydisperse powders initially arranged as two superposed, perfectly-segregated packed systems. As fluidization occurs, the simulation tracks the evolution in time and physical space of the quadrature nodes and weights and predicts the mixing attained by the system. To validate the method, we compare computational predictions with experimental results

Application of robust control in unmanned vehicle flight control system design

The robust loop-shaping control methodology is applied in the flight control system design of the Cranfield A3 Observer unmanned, unstable, catapult launched air vehicle. Detailed linear models for the full operational flight envelope of the air vehicle are developed. The nominal and worst-case models are determined using the v-gap metric. The effect of neglecting subsystems such as actuators and/or computation delays on modelling uncertainty is determined using the v-gap metric and shown to be significant. Detailed designs for the longitudinal, lateral, and the combined full dynamics TDF controllers were carried out. The Hanus command signal conditioning technique is also implemented to overcome actuator saturation and windup. The robust control system is then successfully evaluated in the high fidelity 6DOF non-linear simulation to assess its capability of launch stabilization in extreme cross-wind conditions, control effectiveness in climb, and navigation precision through the prescribed 3D flight path in level cruise. Robust performance and stability of the single-point non-scheduled control law is also demonstrated throughout the full operational flight envelope the air vehicle is capable of and for all flight phases and beyond, to severe launch conditions, such as 33knots crosswind and exaggerated CG shifts. The robust TDF control law is finally compared with the classical PMC law where the actual number of variables to be manipulated manually in the design process are shown to be much less, due to the scheduling process elimination, although the size of the final controller was much higher. The robust control law performance superiority is demonstrated in the non-linear simulation for the full flight envelope and in extreme flight conditions

Effects of errorless learning on the acquisition of velopharyngeal movement control

Session 1pSC - Speech Communication: Cross-Linguistic Studies of Speech Sound Learning of the Languages of Hong Kong (Poster Session)The implicit motor learning literature suggests a benefit for learning if errors are minimized during practice. This study investigated whether the same principle holds for learning velopharyngeal movement control. Normal speaking participants learned to produce hypernasal speech in either an errorless learning condition (in which the possibility for errors was limited) or an errorful learning condition (in which the possibility for errors was not limited). Nasality level of the participants’ speech was measured by nasometer and reflected by nasalance scores (in %). Errorless learners practiced producing hypernasal speech with a threshold nasalance score of 10% at the beginning, which gradually increased to a threshold of 50% at the end. The same set of threshold targets were presented to errorful learners but in a reversed order. Errors were defined by the proportion of speech with a nasalance score below the threshold. The results showed that, relative to errorful learners, errorless learners displayed fewer errors (50.7% vs. 17.7%) and a higher mean nasalance score (31.3% vs. 46.7%) during the acquisition phase. Furthermore, errorless learners outperformed errorful learners in both retention and novel transfer tests. Acknowledgment: Supported by The University of Hong Kong Strategic Research Theme for Sciences of Learning © 2012 Acoustical Society of Americapublished_or_final_versio