Page 512 - Mechanical Engineers' Handbook (Volume 2)

Mechanical Engineers’ Handbook: Instrumentation, Systems, Controls, and MEMS, Volume 2, Third Edition.

Edited by Myer Kutz

Copyright  2006 by John Wiley & Sons, Inc.

CHAPTER 13
CONTROL SYSTEM
PERFORMANCE MODIFICATION
Suhada Jayasuriya
Department of Mechanical Engineering
Texas A&M University
College Station, Texas
1 INTRODUCTION 503 5 ROOT LOCUS 517
5.1 Angle and Magnitude Conditions 518
2 GAIN AND PHASE MARGIN 504 5.2 Time-Domain Design Using the
2.1 Gain Margin 504 Root Locus 523
2.2 Phase Margin 504 5.3 Time-Domain Response versus
2.3 Gain-Phase Plots 505 s-Domain Pole Locations 531
2.4 Polar Plot as a Design Tool in
the Frequency Domain 506 6 POLE LOCATIONS IN THE
z-DOMAIN 532
3 HALL CHART 509 6.1 Stability Analysis of
3.1 Constant-Magnitude Circles 510 Closed-Loop Systems in the
3.2 Constant-Phase Circles 510 z-Domain 535
3.3 Closed-Loop Frequency Response 6.2 Performance Related to
for Nonunity Feedback Systems 511 Proximity of Closed-Loop Poles
3.4 Closed-Loop Amplitude Ratio 512 to the Unit Circle 536
6.3 Root Locus in the z-Domain 537
4 NICHOLS CHART 513
4.1 Closed-Loop Frequency 7 CONTROLLER DESIGN 538
Response from That of Open
Loop 514 REFERENCES 540
4.2 Sensitivity Analysis Using the
Nichols Chart 516 BIBLIOGRAPHY 540

1 INTRODUCTION
Chapter 12 presents a wide variety of tools for analyzing closed-loop control systems. This
chapter focuses on the development of additional analytical tools for closed-loop control
systems, tools aimed at performance modification and improvement. Each successive tool
presented in this chapter is useful in its ability to predict system performance and to pinpoint
the appropriate modifications so that the closed-loop system will meet its required perform-
ance objectives.
Chapter 14 also addresses the problem of system modifications, but there the emphasis
is to work with the adjustable parameters of a device called the servocontroller to achieve
the necessary result.

Reprinted from Instrumentation and Control, Wiley, New York, 1990, by permission of the publisher.

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