Control of Complex Systems

The world of artificial systems is reaching complexity levels that es­ cape human understanding. Surface traffic, electricity distribution, air­ planes, mobile communications, etc. , are examples that demonstrate that we are running into problems that are beyond classical scientific or engi­ neering knowledge. There is an ongoing world-wide effort to understand these systems and develop models that can capture its behavior. The reason for this work is clear, if our lack of understanding deepens, we will lose our capability to control these systems and make they behave as we want. Researchers from many different fields are trying to understand and develop theories for complex man-made systems. This book presents re­ search from the perspective of control and systems theory. The book has grown out of activities in the research program Control of Complex Systems (COSY). The program has been sponsored by the Eu­ ropean Science Foundation (ESF) which for 25 years has been one of the leading players in stimulating scientific research. ESF is a European asso­ ciation of more than 60 leading national science agencies spanning more than 20 countries. ESF covers has standing committees in Medical Sci­ ences, Life and Environmental Sciences, Physical and Engineering Sci­ ences, Humanities and Social Sciences. The COSY program was ESF's first activity in the Engineering Sciences. The program run for a period of five years starting January 1995.

1. Introduction.- 1.1 Complex Systems and Control.- 1.2 Complex Engineering Systems.- 1.3 The Role of Feedback.- 1.4 Dynamics and Control.- 1.5 The Nature of Failures.- 1.6 Research Challenges.- 1.7 About the Book.- 2. Modeling Complex Physical Systems.- 2.1 Introduction.- 2.2 The Modelica Project.- 2.3 Composition Diagrams.- 2.4 Modelica Details.- 2.5 Non-causal Modeling.- 2.6 Advanced Modeling Features.- 2.7 Standard Libraries.- 2.8 Future Development.- 2.9 Conclusions.- 3. Passivity-based Control of Non-linear Systems.- 3.1 Introduction.- 3.2 Passivity and Stability Analysis of Feedback Interconnections.- 3.3 Feedback Passivity and Stabilization.- 3.4 Euler-Lagrange Systems.- 3.5 Disturbance Attenuation and R oo Control.- 4. An Introduction to Forwarding.- 4.1 Introduction.- 4.2 C1 Dissipative Systems.- 4.3 C1 Dis sipative Systems via Reduction or Extension.- 4.4 Exact Change of Coordinates.- 4.5 Approximate Change of Coordinates.- 5. Iterative Identification and Control Design.- 5.1 Introduction.- 5.2 Youla Parametrization.- 5.3 A Generic Two-degree of Freedom Controller.- 5.4 Optimization of the Generic Scheme.- 5.5 A New Closed-loop System Parametrization.- 5.6 Asymptotic Variances for K-B-Parametrization.- 5.7 Iterative Controller Refinement.- 5.8 Robustness and Sensitivity.- 5.9 Product Inequalities.- 6. Learning Control of Complex Systems.- 6.1 Introduction.- 6.2 Model Structures for Learning.- 6.3 Control Structures for Learning.- 6.4 Learning Paradigms.- 6.5 A General Framework for On-line Learning.- 6.6 Validation.- 6.7 Conclusions.- 7. Software for Complex Controllers.- 7.1 Introduction.- 7.2 An Evolving Paradigm.- 7.3 Emerging Software Concepts.- 7.4 On to Standardization.- 7.5 Sample Complex Software Controllers.- 7.6 The Future of Software for Control.- 8. Fault-tolerant Control Systems.- 8.1 Introduction.- 8.2 Basic Definitions.- 8.3 Analysis of Fault Propagation.- 8.4 Analysis of Structure.- 8.5 Recoverability.- 8.6 Autonomous Fault-tolerant Control.- 8.7 An Example: Ship Propulsio.- 8.8 Summary.- 9. Fault Detection and Isolation.- 9.1 The Principle of Model-based Fault Diagnosis.- 9.2 Signal-based FDI Approach.- 9.3 Quantitative Model-based FDI Approach.- 9.4 Qualitative Model-based FDI Approach.- 9.5 Summary.- 10. Residual Generation for FDI in Non-linear Systems.- 10.1 Introduction.- 10.2 Algebraic Approach.- 10.3 Geometric Approach.- 10.4 Conclusion.- 11. Predictive Methods for FTC.- 11.1 Introduction.- 11.2 Predictive Control.- 11.3 Embedding Fault Tolerance in Predictive Control.- 11.4 Model Adaptation and Management.- 11.5 Modifying Control Objectives.- 11.6 Current Industrial Practice.- 11.7 Conclusions.- 12. Three-tank Control Reconfiguration.- 12.1 The Benchmark Problem.- 12.2 Reconfigurability Analysis.- 12.3 Reconfiguration Based on a Qualitative Model.- 12.4 A Hybrid Approach to Reconfigurable Control.- 12.5 A Multi-model-based Reconfigurable Control.- 12.6 A Neural Observer-based Approach.- 12.7 Conclusions.- 13. Ship Propulsion Control and Reconfiguration.- 13.1 Introduction.- 13.2 Ship Propulsion System.- 13.3 Structural Analysis.- 13.4 Fault Detection: A Fuzzy Observer Approach.- 13.5 Fault Detection: Non-linear Approach - 1.- 13.6 Fault Detection: Non-linear Approach - 2.- 13.7 Reconfiguration Using Software Redundancy.- 13.8 Reconfiguration Using Predictive Control.- 13.9 Summary and Conclusions.- 14. Learning Control of Thermal Systems.- 14.1 Introduction.- 14.2 On Thermal System Learning Control.- 14.3 Controlling Kiln Heat Processing.- 14.4 Controlling Reheat Furnace Processes.- 14.5 Hierarchical Control for Quality Ceramic Tiles.- 14.6 Learning Control ofFBC Combustion.- 14.7 Conclusions and Future Research.- 15. Vibration Control of High-rise Buildings.- 15.1 Introduction.- 15.2 Energy and Information.- 15.3 Analytical Mechanics and HRB Modelling.- 15.4 Disturbance Decoupling.- 15.5 Passivity Based Control.- 15.6 Engineering Constraints and Feedback.- 15.7 Feedback Control and Testing.- 15.8 Conclusions and Future Research.- 16. Control of Helicopters.- 16.1 Introduction.- 16.2 Project History.- 16.3 The COSY Program.- 16.4 Hardware System.- 16.5 Software.- 16.6 Design of the Autopilot.- 16.7 Future Development.- 16.8 Conclusions.- 17. Satellite Attitude Control.- 17.1 Introduction to the Attitude Control Problem.- 17.2 Fault-tolerant Control of the 0RSTED Satellite.- 17.3 Stabilization of the Angular Velocity of a Rigid Body.- 17.4 Optimal Slew Maneuvers via Geometric Control Theory.- 17.5 Attitude Control using Magnetorquers as Sole Actuators.- 17.6 Predictive Attitude Control of Small Satellites.- 17.7 Attitude Determination without Sensor Redundancy.- 17.8 Summary.- Appendix A. List of Contributors.- Appendix B. List of Abbreviations.- References.