Applied Digital Control Theory, Design and Implementation. Second Edition

by Leigh, J. R.

• ISBN13: 9780486450513
• ISBN10: 0486450511
• Edition: 2nd
• Format: Paperback
• Copyright: 2006-06-23
• Publisher: Dover Publications

Summary

An essential core text for advanced undergraduate and graduate courses in digital control, this volume develops theoretical foundations and explains how control systems work in real industrial situations. Several case histories assist students in visualizing the theory's applications. After a careful development of theoretical foundations, the text explains the practical role of control systems with detailed reviews of five commercially available distributed control systems. Numerous exercises supplement the overview of theoretical foundations, and the emphasis throughout the text is placed upon robustness and realistic adaptive control as well as the successful application of digital control theory to real problems. 1992 ed.

Table of Contents

Preface to the second edition	xiii
Preface to the first edition	xv
The structure of the book	xvii
Acknowledgements	xix
1 Introduction to the key features of digital control	1	(5)
1.1 Important generalities	1	(1)
1.2 A digital computer in the control loop	1	(3)
1.3 Control of multi-loop processes	4	(1)
1.4 Control of non-constant processes: Adaptive control	5	(1)
1.5 Commercially available computer control systems	5	(1)
2 Discrete-time signals; idealized approximation; frequency spectrum; reconstruction	6	(17)
2.1 Introduction	6	(1)
2.2 The nature of sampled signals	6	(1)
2.3 Loss of information in a sampled signal	7	(2)
2.4 Creation of spurious information in a sampled signal	9	(1)
2.5 The sampling process	9	(4)
2.6 Ideal sampling	13	(1)
2.7 Digital control of a single-input–single-output process	14	(3)
2.8 Reconstruction of the signal ƒ(t) from the discrete-time signal ƒ*(t)	17	(1)
2.9 Approximate reconstruction of ƒ(t) from ƒ*(t) using hold devices	18	(1)
2.10 An approach to the analysis of a control loop containing a digital controller	18	(2)
2.11 Other methods of sampling	20	(1)
Exercises	20	(3)
3 L transform techniques	23	(46)
3.1 Introduction	23	(1)
3.2 The l transform	23	(8)
3.3 The pulse transfer function	31	(3)
3.4 A brief description of three methods for obtaining information on system behavior between sampling instants	34	(4)
3.5 Inverse l transformation to yield time solutions	38	(3)
3.6 Difference equations	41	(4)
3.7 The z plane and its relation with the s plane	45	(10)
3.8 Correspondence between pole locations in the z plane and system time response	55	(1)
3.9 Analysis of a simple loop containing a discrete-time controller	55	(6)
Exercises	61	(8)
4 Methods of analysis and design	69	(42)
4.1 Introduction	69	(1)
4.2 Discretization	69	(16)
4.3 The root-locus diagram	85	(8)
4.4 Frequency-response methods	93	(6)
4.5 Stability tests	99	(4)
Exercises	103	(8)
5 Digital control algorithms	111	(87)
5.1 Introduction	111	(1)
5.2 Design methods	111	(32)
5.3 Design descriptions	143	(2)
5.4 Design realizations: realization of algorithms in terms of unit delays and constant multipliers	145	(3)
5.5 Design considerations	148	(39)
5.6 Oscillations in control loops	187	(1)
Exercises	187	(11)
6 Hardware Systems for Implementation	198	(31)
6.1 Introduction	198	(1)
6.2 Design of input circuits	198	(5)
6.3 Actuators	203	(2)
6.4 Analog interfacing	205	(16)
6.5 Digital interfacing	221	(3)
6.6 Microprocessors for control applications	224	(1)
Exercises	225	(4)
7 Tutorial case histories	229	(132)
7.1 Introduction	229	(1)
7.2 Outline of Problem A: Temperature control achieved by a low-cost personal computer configuration, programmed in RAPID BASIC language	229	(1)
7.3 Computation and interfacing	230	(1)
7.4 Control of data transfer	230	(1)
7.5 Identification of the oven	231	(2)
7.6 Control design	233	(2)
7.7 Choice of sampling interval	235	(2)
7.8 Input quantization	237	(1)
7.9 Alternative approach-Design of a temperature controller to achieve a particular closed-loop behavior	238	(1)
7.10 Comments on the temperature-control application	239	(1)
7.11 Outline of Problem B: Design of a thickness and flatness control system for metal rolling	240	(1)
7.12 Thickness measurement and control	240	(1)
7.13 Flatness measurement	241	(1)
7.14 Flatness control	242	(1)
7.15 Control-system specification	242	(1)
7.16 Choice of sampling interval T for the control loops	242	(1)
7.17 Choice of input-signal scanning arrangement	243	(1)
7.18 Choice of word lengths	244	(1)
7.19 Mathematical models of the process	244	(1)
7.20 Control-algorithm design	244	(1)
7.21 Fixing of the numerator N(z)	245	(1)
7.22 Calculation of the control algorithms	246	(2)
7.23 Realization of the control algorithms	248	(1)
7.24 Implementation	249	(1)
7.25 Program development	249	(1)
7.26 The complete scheme	250	(1)
Exercises	250	(7)
8 State-variable techniques	257	(79)
8.1 Introduction	257	(1)
8.2 The concept of state	257	(1)
8.3 Alternative system descriptions	258	(1)
8.4 The mapping representation of E	259	(2)
8.5 The modelling of continuous-time systems through state-space equations	261	(2)
8.6 Calculation of time solutions using the transition matrix	263	(8)
8.7 Properties of the transition matrix	271	(1)
8.8 Relation between the transfer-matrix description and the vector-matrix description	271	(1)
8.9 Equivalent systems	272	(1)
8.10 System realization	273	(1)
8.11 Stability	273	(1)
8.12 Reachability, controllability, observability and reconstructibility for continuous-time systems	274	(2)
8.13 The unforced state equation in discrete time	276	(1)
8.14 Solution of the discrete-time state equation with forcing	277	(1)
8.15 Obtaining the transform equivalent of the state equation	278	(1)
8.16 Stability tests	278	(1)
8.17 Reachability, controllability, observability and reconstructibility for discrete-time systems	279	(2)
8.18 Canonical state-space representations	281	(12)
8.19 The state-variable approach to control-system design	293	(1)
8.20 Design of non-interacting controllers	293	(5)
8.21 Design to achieve a specified closed-loop characteristic equation	298	(3)
8.22 A brief introduction to optimal control	301	(5)
8.23 State estimation	306	(8)
8.24 The separation theorem	314	(2)
Worked examples	316	(10)
Exercises	326	(10)
9 Control of large-scale systems	336	(25)
9.1 Introduction	336	(1)
9.2 Initial approaches to system decomposition	337	(2)
9.3 Hierarchical control	339	(1)
9.4 Multilayer control	339	(2)
9.5 Multilayer optimization	341	(4)
9.6 Digraphs as a tool in the modelling of complex systems	345	(7)
9.7 Multilevel control	352	(1)
9.8 The coordination problem in multilevel control	353	(1)
9.9 The steady-state coordination problem in multilevel control	354	(1)
9.10 The direct method of coordination	355	(1)
9.11 Implementation of the direct method using penalty functions	356	(1)
9.12 The interaction balance method	357	(1)
9.13 Coordination with feedback for on-line control	358	(1)
Exercises	359	(2)
10 Control system implementation and integration	361	(24)
10.1 Introduction	361	(1)
10.2 Implementation—some initial points	361	(1)
10.3 Computers for control design, for real-time software development and validation and for implementation	362	(1)
10.4 Computers for control applications	363	(2)
10.5 Distributed Control System (DCS) for control of interlinked processes	365	(14)
10.6 Integration of process control systems into overall systems of plant management	379	(1)
10.7 Safety-critical and high-integrity designs	380	(3)
10.8 The interaction of control with information technology (IT) and with software engineering	383	(1)
Exercises	384	(1)
11 Commercially available computer control systems and their industrial application	385	(67)
11.1 Introduction	385	(1)
11.2 Computer integrated manufacturing through the Fisher PROVOXplus System	386	(10)
11.3 The Bristol Babcock System	396	(2)
11.4 The TCS 6000 System	398	(3)
11.5 The Contronic P Systems of Hartmann and Braun	401	(3)
11.6 The Analog Devices System	404	(5)
11.7 The Siemens Teleperm M System	409	(5)
11.8 The Honeywell TDC System	414	(16)
11.9 The Foxboro System	430	(1)
11.10 Case history C: Control of a 1000 tonne press	430	(2)
11.11 Case history D: Control of a fully automatic woodworking machine	432	(1)
11.12 Case history E: Control of a paper-mill complex	433	(1)
11.13 Case history F: Computer integrated manufacture at a photographic film plant	434	(3)
11.14 Case history G: Computer integrated manufacture at a chemical manufacturing plant	437	(3)
11.15 Case history H: Control of a pumped storage scheme	440	(2)
11.16 Case history I: Control of a batch process	442	(4)
11.17 Case history J: Enhanced boiler drum level control	446	(5)
11.18 Concluding Remarks	451	(1)
11.19 Miniproject	451	(1)
12 Adaptive and robust control	452	(39)
12.1 Introduction	452	(2)
12.2 Some simple initial ideas on adaptive and self-tuning control	454	(3)
12.3 Approaches to adaptive control	457	(1)
12.4 Approaches to self-tuning control	458	(1)
12.5 Identification methods for adaptive and self-tuning control	458	(1)
12.6 Linear difference equation process models	459	(3)
12.7 Approaches to the control design phase	462	(1)
12.8 Model reference adaptive control (MRAC)	463	(3)
12.9 Trajectory following control	466	(2)
12.10 Controller scheduling	468	(3)
12.11 Batch-to-batch adaptation for batch processes	471	(1)
12.12 Predictive–iterative control using a fast process model	472	(1)
12.13 Commercially available adaptive controllers	473	(2)
12.14 Robustness	475	(8)
12.15 Some practical points on process identification and modelling	483	(4)
12.16 Some final realism	487	(1)
12.17 Conclusions	488	(1)
Miniprojects	489	(2)
Appendix A The structure and operation of a peripheral interface adaptor (PIA chip)	491	(7)
A1 Addressing the PIA chip	492	(2)
A2 PIA control lines	494	(4)
Appendix B Examples of VME bus and Personal Computer Systems for control implementation	498	(2)
Appendix C Tables of transform pairs	500	(3)
Bibliography—general	503	(5)
References—adaptive, self-tuning and robust control	508	(12)
Glossary of symbols	520	(2)
Index	522