Page 629 - 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 15
CONTROLLER DESIGN
Thomas Peter Neal
Consultant
Lake View, NY
1 INTRODUCTION 620 5.3 Feedforward 654
2 FUNDAMENTALS OF CLOSED- 6 PID CONTROLLERS 656
LOOP PERFORMANCE 621 6.1 Equivalence to Frequency
2.1 Accuracy and Loop Gain 621 Compensation 656
2.2 Dynamic Response and Stability 625 6.2 Systems Having No Inherent
Integration 659
3 FREQUENCY COMPENSATION 6.3 Systems Having an Inherent
TO IMPROVE OVERALL Integration 660
PERFORMANCE 632
3.1 Well-Damped Systems 633 7 EFFECTS OF NONLINEARITIES 660
3.2 Poorly Damped Systems 637 7.1 Simple Nonlinearities 663
3.3 Higher Order Effects 641 7.2 Complex Nonlinearities 668
7.3 Computer Simulation 668
4 INNER FEEDBACK LOOPS 645
4.1 Derivatives of the Controlled 8 CONTROLLER
Variable 646 IMPLEMENTATION 669
4.2 Alternative Inner Loop Variables 649 8.1 Analog Controllers 669
4.3 Nonelectronic Inner Loops 650 8.2 Hard-Wired Digital Controllers 672
8.3 Computer-Based Digital
5 PREFILTERS AND Controllers 673
FEEDFORWARD 651
5.1 Lag Prefilters 651 REFERENCES 677
5.2 Lead Prefilters 652

1 INTRODUCTION

The purpose of this chapter is to provide a basis for the specification and functional design
of electronic servocontrollers. No attempt is made to treat the subject of electronic circuit
design. Instead, the goal is to aid the engineer in selecting and applying a suitable off-the-
shelf controller or in specifying the controller requirements to a circuit designer. The em-
phasis is on position, velocity, or force control of mechanical loads, although many of the
techniques are applicable to controller design in general. Specialized subjects such as mul-
tiaxis control and adaptive control are beyond the scope of this chapter.
As a starting point, it is presumed that a servoactuator has been selected and mounted,
together with a suitable power supply, drive amplifier, and mechanical drive mechanism. In
addition, the primary feedback transducer has been chosen, and a simple loop closure has
been analyzed to determine whether the specified closed-loop performance can be obtained.

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

620