Automation and Control in Transport

Automation and Control in Transport reviews the significant advances in transport automation and control. All the present and future foreseeable modes of transport, particularly railways, are treated mathematically. Topics range from dynamic systems to route capacity, vehicle spacing, traffic congestion and regulation, and traffic surveillance and control. Vehicle detection and identification, sorting and marshalling, control of acceleration and power, steering, and control of braking are also given consideration. This volume consists of 16 chapters and begins with a discussion of the dynamic behavior of a system (that is, how it responds to changing situations) from the point of view of control engineering. Open-loop systems, closed-loop systems, and the use of a phase-plane diagram to represent the response of a control system are described. The chapters that follow focus on the capacity of a transport system based on the laws for vehicle following, signaling as a means of controlling vehicle spacing in railways, and traffic regulation to address problems of congestion. The reader is also introduced to the use of computers to aid in traffic surveillance and control, means for detecting and identifying the presence of a vehicle, and communication of control signals to moving vehicles. The book concludes by assessing future prospects for transport automation and control. This book will be of interest to traffic engineers as well as students and practitioners of mechanical engineering.

Foreword

Preface

Notation

1. Dynamic Systems

1.1 System Concepts

1.2 Open-Loop Systems

1.3 "Feedback"—Closed-Loop Systems

1.4 The Phase-Plane Diagram

2. Route Capacity—Laws for Vehicle Following

2.1 Lane Capacity

2.2 Car-Following Theory

2.3 Automatic Vehicle Systems

3. Control of Vehicle Spacing—Railway Signaling

3.1 Necessity for Signaling on Railways

3.2 The "Train-Order" System

3.3 The "Block" System

3.4 Lock and Block

3.5 Multiple-Aspect Signaling

4. Problems of Congestion—Traffic Regulation

4.1 Random Events

4.2 Queues—Poisson Arrivals—Constant Service Times

4.3 Exponential Service Times

4.4 Effect of Delays on Headway of Signaled Systems

4.5 Statistical Aspects of Car-Following Behavior

4.6 Traffic Waves

5. Computer Aids to Operation—Traffic Surveillance and Control

5.1 Application of Digital Computers

5.2 Continuous Progress Control (C.P.C.), Dynamic Programming

5.3 Optimum Train Sequence

5.4 Traffic Surveillance and Control

5.5 Control of Cascaded Vehicles

5.6 System Flow Charts

5.7 Train Describers

6. Measurement of Power—Analogue Computing

6.1 Mechanical Manipulation of Data

6.2 Equivalent Mechanical and Electrical Quantities

6.3 Potential and Flow

6.4 Operational Amplifiers

6.5 Vehicle Suspension Analogy

6.6 Application to Strings of Vehicles

6.7 Hybrid Computers

6.8 Simulation of Service Environment

7. Vehicle Detection

7.1 Presence Detectors

7.2 Track Circuits

7.3 Jointless Track Circuits

7.4 Guided Radar

8. Vehicle Identification

8.1 The "Identra" System

8.2 Bus Electronic Scanning Indicator

8.3 Automatic Wagon-Recording System

9. Communication of Control Signals to Moving Vehicles

9.1 Automatic Warning Systems—Cab Signaling

9.2 The "Indusi" System

9.3 The "Signum" System

9.4 Beacon devices

9.5 Coded Track Circuit

9.6 Professor Poupe's System of Coded Track Circuits

9.7 Use of Continuous Conductors in the Track

9.8 Combination of Magnetic and Inductive Loop Systems

10. Interlocking—Sequence Control

10.1 Mechanical Interlocking

10.2 Boolean Algebra

11. Sorting and Marshalling

11.1 The Hump Yard

11.2 Automatic Retarders

11.3 Dowty Retarders

12 Control of Acceleration and Power

12.1 Limitations

12.2 Equations of Motion

12.3 Values of Resistance Coefficient

12.4 Estimation of Distance-Time Relationships

12.5 Coasting

12.6 Control of Engine Speed

12.7 Automatic Transmissions

12.8 Control of Electric Motive Power

12.9 Use of Transductors in Power Control

12.10 Application of Induction Motors

12.11 Wheel-Slip Control

12.12 Control of Diesel Power

12.13 Adaptive Control

12.14 Shock Factors in Acceleration

13. Control of Braking

13.1 Forms of Braking

13.2 Physiological Aspects

13.3 Control of Slip (Slow up)

13.4 "On-Tread" Braking

13.5 "Off-Tread" Braking

13.6 Servo Actuation

13.7 The Compressed-Air Brake

13.8 The Electro-Pneumatic (E.P.) Brake

13.9 The Vacuum Brake

14. Steering—Directional Stability

14.1 Steering

14.2 Directional Stability

14.3 Hertzian Contact

14.4 Running of Coned Wheels

14.5 Inscription within Sharp Curves—Steering by Flanges

14.6 Oscillation of Bogies

14.7 Motion on Curves at Speed

14.8 Effect of Oscillation on Passengers

15. Automatic Railways

15.1 General Principles

15.2 Analysis of Human Contribution under the Present System

15.3 Possible Systems for Intensively Used Passenger Lines

15.4 Existing Installations

15.5 Systems for High-Speed Working

16. Possibilities for the Future

16.1 The Need for Development of New Transport Modes

16.2 Possible Improvements in Control on the Highway

16.3 High Capacity Systems—Effect of Station Stops

16.4 Mono- and Duorails

16.5 Transit Expressways

16.6 Steerable Wheels

16.7 Blake System

16.8 Air-Cushion Support

16.9 Linear Motors

Appendix I

Theory of Control

1. Equivalence of Dynamic and Active Systems

2. Literature Available

3. The Laplace Transform-Transfer Function

4. Effect of Time Delay

5. Criteria for Stability

6. Root Locus Plots

7. Nyquist and Bode Representation

8. Common forms of Non-Linearity

9. The Describing Function

10. Inverse Nyquist or Whitely Diagram

11. Liapunov's Second Method

12. Random Inputs

13. On-Line Control—Sampled Data

Appendix II

The S.I. Units

1. Advantages and Use of System

2. Conversion Factors

Name Index

Subject Index