Control Systems with Input and Output Constraints

ISBN-13: 9781852333874 / Angielski / Miękka / 2003 / 504 str.

Adolf Hermann Glattfelder; A. H. Glattfelder; W. Schaufelberger

Opis

In current industrial control, PID technology is firmly established as the standard. Often, however, high control loop performance can only be obtained within narrow limits around a given steady-state operating point. If perturbations introduced by any reference or load change are outside these limitations then the actuators will constrain the system inputs. Other operational limits may also be imposed by additional variables within the plant producing output constraints. A typical method of dealing with input and output constraints, especially for PID control, has been the empirical design and implementation of an intuitive solution to an individual plant and its constraints. Such ad hoc solutions perform surprisingly well but often remain in the form of isolated practical know-how without a more general scientific basis. Control Systems with Input and Output Constraints develops this empirical approach by demonstrating how particular answers to particular industrial design problems can be systematized to cope with a wide variety of simple and more complex situations. Each class of design problems is presented in five parts: industrial situation; problem statement; currently available control structures; benchmark simulation to obtain typical transient response and nonlinear stability analysis to relate structure to response. Links to optimal control and model predictive control are also explored. These steps help the reader to learn how to choose or adapt a control architecture and design or analyse it on a systematic basis. Features: associated website contains many ready-made examples and case studies using MATLAB^(r)/Simulink^(r) to which extensive reference is made throughout the text facilitating understanding and saving time; exercises interspersed throughout each chapter that allow the student to confirm progress as he/she proceeds; logical five-step design procedure for each problem class moving from a particular industrial example to the informed choice of generic controller and the preparation of closed loop analysis. Control Systems with Input and Output Constraints will be of great benefit to advanced students of control looking to pursue a career in process and/or plant control or in applications-oriented research. The practical basis of the presentation, the systematic design procedure, the restraint on mathematical formalism and emphasis on implementability will also appeal to industrial control engineers.

Recenzje

From the reviews:

The authors emphasize that they have taken an engineering approach instead of a mathematical approach in the book. This is true and it makes the book interesting not only for researchers in the field, but also for students that should learn about the problems and the solutions. To facilitate these studies, there is a website associated with the book where the Matlab/Simulink programs used in the examples are available.

The book is also a valuable reference for engineers faced with implementation problems. The number of such engineers is large, and the number of control loops implemented poorly with respect to saturations and override control is large and increasing. Several of the dominating suppliers of instrument systems for process control deliver products where the anti-windup and override control works well for the simple feedback loop, but where the problems are unsolved, or solved in an erroneous way, when it comes to more complicated controller structures involving e.g. cascade couplings, feed-forward, and selectors. There is a need to improve the knowledge about these problems, and this book is one step on the way to achieve this.

Professor Glattfelder and Professor Schaufelberger have been the leading experts in the area of control with constraints for a long time. They have now summarized their experience in the present book, and they have succeeded in their intention to produce the first reference in the area that will be available for a broad audience. I think that this book will be a standard reference for a long time.

Control Engineering Practice 13 (2005) 131 (Reviewer: Tore Hägglund)

 

It is difficult to overstate the importance of considering control constraints in control system design: such constraints have well-known implications for the behaviour of the resulting closed-loop system, and ignoring these constraints can lead to a dramatic loss of performance and, potentially, stability...

The subject of this review is the first and, so far, the only, book to address the topic of anti-windup compensation, and it is authored by two eminent authorities in the field. Professors Glattfelder and Schaufelberger are regular contribuotrs  to the anti-windup literature and accomplished practical control engineers;...

The book is essentially split into two parts: the first part covers PI control of dominant first order systems; the second part generalizes the concepts of the first to plants of higher order with more complex controllers and also lays the foundations for multivariable anti-windup/override control.

An interesting feature of the book is the "inductive" approach which the authors adopt; rather than starting from a general treatment of the problem, the authors prefer to point out the key features of their ideas using relatively simple systems at first and then extend these ideas to more complex systems...

Overall, this is a well-written and well-structured book in which the authors have devoted considerable attention to imparting their message to the reader in a simple and direct manner... After reading the book, one is left with the sense that the schemes described within the book are not purely abstract, but that they can be applied in practice with great benefit.

International Journal of Robust and Nonlinear Control 14 (2004) 1299 - 1300  (Reviewer: Matthew Turner)

In Control Systems with Input and Output Constraints, the authors address control problems for linear plants ... . In Part I of the book, the authors begin their discussion of control with input constraints ... . The nice feature of Part I of the book is that it is targeted to an industrial audience and is written in a practically oriented style ... . Part II can be seen as an interesting overview of recent advanced techniques for more complicated problem settings.

IEEE Control Systems Magazine June (2005) 96 - 99  (Reviewers: Andrew R. Teel and L. Zaccarian)

A typical method of dealing with input and output constraints, especially for PID control, has been the empirical design and implementation of an intuitive solution to an individual plant and its constraints. ... Control Systems with Input and Output Constraints develops this empirical approach ... . The practical basis of the presentation, the systematic design procedure, the restraint on mathematical formalism ... will also appeal to industrial control engineers. Written for graduate students in control engineering, academic researchers in control engineering ... .

Automatisierungstechnische Praxis ATP 45/12 (2003)

"This book familiarizes the reader with PID control design methodologies when the inputs and/or outputs can saturate. The authors present their topics in an inductive manner from simple cases to more complicated ones, but they do not loose themselves in this way. The text is well structured. ... The book is of interest to engineers and students in control system design.

Zentralblatt MATH 1030 (2004) (Reviewer: A. Akutowicz)

Spis treści

1 Introduction.- 1.1 A Typical Case.- 1.2 A Historical Perspective.- 1.3 The Control Problem.- 1.3.1 Control Systems with Input Constraints.- 1.3.2 Control Systems with Mode Switch.- 1.3.3 Control Systems with Output Constraints.- 1.4 Expected Control Performance.- 1.5 Methods.- 1.5.1 Optimal Control.- 1.5.2 Numerical Optimization: Model Predictive Control.- 1.5.3 The Intuitive Approach.- 1.6 Contents.- 1.7 Objectives.- I Standard Techniques.- 2 PI Control with Input Saturations.- 2.1 John’s Case.- 2.1.1 Modeling.- 2.1.2 The Mechanical Governor.- 2.1.3 The Electronic Regulator.- 2.1.4 Summary.- 2.2 Problem Statement and Test Cases.- 2.3 The Reset Windup Effect.- 2.4 Antiwindup Structures.- 2.4.1 The Generic Antiwindup Feedback Structure.- 2.4.2 Control Conditioning.- 2.4.3 Reference Conditioning.- 2.4.4 Self-conditioning.- 2.4.5 Summary.- 2.5 Transient Responses for the Test Cases.- 2.5.1 The Effect of Antiwindup Feedback Structure.- 2.5.2 The Effect of Controller Tuning.- 2.5.3 Overshoot Analysis.- 2.5.4 The Effect of the Relative Pole Shift ÜT.- 2.5.5 Summary.- 2.6 Stability properties.- 2.6.1 Motivation.- 2.6.2 Methods.- 2.6.3 A Generic Result.- 2.6.4 Stability Analysis of the Test Cases.- 2.6.5 Estimating the Range of Attraction.- 2.6.6 Summary.- 2.7 Relations to Optimal Control.- 2.7.1 Motivation.- 2.7.2 The Exact Solution.- 2.7.3 Ongoing Control.- 2.8 Case Study: Batch Reactor Temperature Control.- 2.8.1 The process and the main control task.- 2.8.2 The Plant Model.- 2.8.3 Parameter Values.- 2.8.4 The Controller.- 2.8.5 The Design Program.- 2.8.6 Typical Resuhs.- 2.9 Summary.- 3 PI Control with Output Constraints.- 3.1 Arthur’s Case.- 3.1.1 Extending the Plant Model.- 3.1.2 Arthur’s Solution.- 3.1.3 An Advanced Solution.- 3.2 The Basic Concept.- 3.2.1 Problem Statement.- 3.2.2 Typical Controller Structures.- 3.3 The Benchmark Test.- 3.4 Structures for Output Constraint Control.- 3.4.1 The Nonhnear-Additive Concept.- 3.4.2 The Selector Concept.- 3.4.3 The Cascade-Limiter Concept.- 3.5 The Generic Structure.- 3.5.1 A First Version, for Direct Implementation.- 3.5.2 A Second Version, for Stability Analysis.- 3.6 Stability Analysis.- 3.6.1 The Cascade-Limiter Form.- 3.6.2 The Nonhnear-Additive and Selectors Forms.- 3.7 Stability Properties of the Test Case.- 3.8 Relations to Minimum Time Control.- 3.9 Case Study (continued): Batch Reactor Temperature Control..- 3.9.1 The Process and the Main Control Task.- 3.9.2 The Plant Model.- 3.9.3 Parameter Values.- 3.9.4 The Controller.- 3.9.5 The Design Program.- 3.9.6 Typical Results.- 3.10 Summary.- 4 PI Control with Input and Output Constraints.- 4.1 Problem Statement.- 4.1.1 The Plant Model.- 4.1.2 The Basic Control Idea.- 4.2 Benchmark System.- 4.3 Structures and Transient Responses.- 4.3.1 Form A: Sequential Max-Min-Selection.- 4.3.2 Form B: Parallel Selection.- 4.3.3 Form C: “Lowest Wins”.- 4.3.4 Form D: Sequential Nonhnear Additive.- 4.3.5 Form E: Cascade Limiter.- 4.4 Performance Analysis.- 4.4.1 Introduction.- 4.4.2 Applying Open Loop Control Sequences u(t).- 4.4.3 Generating u(t) by Proportional Feedback and Selection.- 4.4.4 Comparison.- 4.4.5 Adding Integral Action with Antiwindup Feedback.- 4.4.6 Back to the Benchmark.- 4.5 Stability Analysis.- 4.5.1 The Multivariable Circle Criterion Approach.- 4.5.2 An illustrative example.- 4.5.3 The Phase Plane Partitions Approach.- 4.5.4 A Modified Approach.- 4.5.5 A Fourth Approach to Design for Stability.- 4.5.6 Summary and Generalization.- 4.6 Case Study: Elevator Positioning Control.- 4.6.1 Plant Description and Data.- 4.6.2 Mathematical model.- 4.6.3 Suggestions for the Control System Design and Analysis.- 4.7 Summary.- 5 Further Topics on PI (aw) Control.- 5.1 PI Control with Actuator Slew and Stroke Constraints.- 5.1.1 Motivation.- 5.1.2 Actuator Modeling.- 5.1.3 Control Structures and Transient Response.- 5.1.4 An Approximation.- 5.1.5 Stability Analysis.- 5.1.6 An Implementation Alternative.- 5.2 Pl(aw) Control with Derivative Action.- 5.2.1 Introduction.- 5.2.2 The Benchmark.- 5.2.3 Transient Response.- 5.2.4 Some Solutions.- 5.2.5 Stability Analysis.- 5.2.6 Summary.- 5.3 PI(aw) Control with Measurement Noise.- 5.3.1 Introduction.- 5.3.2 Louis’ Problem.- 5.3.3 The High-Frequency Disturbance Model.- 5.3.4 PI(aw) Control.- 5.3.5 PI(aw) Control with Derivative Action.- 5.3.6 PI(aw)-P cascade control.- 5.3.7 Some Solutions.- 5.3.8 Conclusion.- II Advanced Techniques.- 6 Generalized Antiwindup.- 6.1 Introduction.- 6.2 A Motivating Example: Peter’s Case.- 6.2.1 The Control Loop.- 6.2.2 Transient Responses.- 6.2.3 Peter’s Analysis.- 6.3 Problem Statement.- 6.3.1 The Plant.- 6.3.2 Controller structures.- 6.3.3 Controller Parameters.- 6.3.4 Test Sequence.- 6.3.5 Saturation Limits.- 6.3.6 Antiwindup Feedback.- 6.4 Nonlinear Stability Analysis.- 6.4.1 The P+ Case.- 6.4.2 Stability Charts.- 6.4.3 The I(aw)-P+ Case.- 6.4.4 Another Approach to the Graphic Stability Test.- 6.5 Transient Analysis.- 6.6 Design Methods: An Overview.- 6.7 Design by De-tuning ?.- 6.8 The “Nested Loops” Method.- 6.8.1 Transient Response.- 6.8.2 Stability Properties.- 6.8.3 Checking the Design Procedure.- 6.9 First-order Dynamic Antiwindup Feedback.- 6.9.1 The Design Procedure.- 6.9.2 Stability Analysis.- 6.9.3 Checking Peter’s Method.- 6.10 Trajectory Generators with Antiwindup Feedback.- 6.10.1 The Design Procedure.- 6.10.2 Stability Properties.- 6.10.3 Checking the Transient Response.- 6.11 The “Continued States” Concept.- 6.12 The Group of “Add-on Output Constraints”.- 6.13 The Cascade Limiter Method.- 6.13.1 Problem Specification.- 6.13.2 The Design Procedure.- 6.13.3 Transient Response.- 6.13.4 Stability Analysis.- 6.14 Selection for Approach Speed.- 6.14.1 The Design Procedure.- 6.14.2 The Second-order Case G(s) = l/(sT)2.- 6.14.3 The Third-order Case G(s) = l/(sT)3.- 6.15 Selection for Lower-bandwidth R1-Control.- 6.15.1 The Design Procedure.- 6.15.2 Stability Properties.- 6.15.3 Transient Response.- 6.15.4 Checking the design procedure.- 6.16 Links to Model Predictive Control.- 6.16.1 Introduction.- 6.16.2 The Benchmarks.- 6.16.3 Classic Model Predictive Control.- 6.16.4 Exphcit Model Predictive Control.- 6.16.5 Comparison with Previous Design Methods.- 6.17 Summary and Outlook.- 7 Generalized Override Control.- 7.1 Introduction.- 7.2 Systems with Dominant First-order Plants.- 7.2.1 Actuation on the Inflow.- 7.2.2 Actuation on the Outflow: Direct vs. Reverse Control..- 7.2.3 Main Control on the Inflow and Overrides on the Outflow.- 7.2.4 Output Limitation with N2 > N1.- 7.3 Systems with Dominant Higher-order Plants.- 7.3.1 Open Integrator Chain Plants.- 7.3.2 Output Constraint Control on a Flexible Transmission..- 7.4 Load Gradient Control.- 7.4.1 Henry’s Case.- 7.4.2 Modeling.- 7.4.3 Controller Structures and Transient Response.- 7.4.4 Stability properties.- 7.4.5 Some Suggestions for Case Studies.- 7.5 Override Action on the Reference Input.- 7.5.1 Introduction.- 7.5.2 The Benchmark.- 7.5.3 The Design Targets.- 7.5.4 Form A: Nonlinear y2-Feedback.- 7.5.5 Form B: Override Structure with P Controllers.- 7.5.6 Form C: Override Control with Integral Action.- 7.5.7 Summary.- 7.6 A Compromise Between y1- and y2-Control.- 7.7 Links to Model Predictive Control.- 7.7.1 Introduction.- 7.7.2 Case ii: The Double-integrator Plant.- 7.7.3 Case iii: The Triple-integrator Plant.- 7.7.4 Conclusions.- 7.8 Summary.- 8 Multivariable Control with Constraints.- 8.1 Introduction.- 8.2 An Overview.- 8.2.1 Multiple Overrides.- 8.2.2 Multiple Actuators of the Same Type.- 8.2.3 Sequentially Acting Control Loops.- 8.2.4 Parallel-acting Control Loops.- 8.2.5 The General Multi-input Multi-output Case.- 8.3 Parallel Actuators.- 8.3.1 Structure.- 8.3.2 Transient Response and Stability Analysis.- 8.4 Sequenced Control Loops.- 8.4.1 Structure.- 8.4.2 Transient Response.- 8.4.3 Stability Analysis.- 8.5 Parallel Control Loops.- 8.5.1 The Plant Model.- 8.5.2 State Feedback Control.- 8.5.3 Additional Integral Action in the Local Controllers.- 8.5.4 Stability Analysis.- 8.6 Interacting Control Loops.- 8.6.1 The Plant.- 8.6.2 Local P Controllers.- 8.6.3 Decoupling Control.- 8.6.4 A Different Control Concept.- 8.6.5 Transient Response.- 8.7 Summary.- 9 Conclusion.- 9.1 Approach.- 9.2 Achievements.- 9.3 Limitations.- 9.4 Some Further Research Areas.- A Nonlinear Stability Tests.- A.l The Canonical Loop Structure and Stability of Motion.- A.2 Final Steady State and the Sector Criteria.- A.3 Limit Cycles and the Describing Function Method.- A.4 Summary.- References.