Modern Practice in Servo Design

Modern Practice in Servo Design

International Series of Monographs in Electrical Engineering

1st Edition - January 1, 1970

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  • Editor: D. R. Wilson
  • eBook ISBN: 9781483145471

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International Series of Monographs in Electrical Engineering, Volume 2: Modern Practice in Servo Design focuses on servomechanics and feedback control systems. The selection first takes a look at basic servomechanism theory, including block diagrams, servo components and compensation, power amplification, absolute stability, transfer functions, and frequency response design methods. The book then discusses the design of a large servomechanism and development of the servo design, as well as digital servo techniques, effects of disturbances, performance specification, mechanical resonance, and completed control loop and its stability. The text describes the design of large antennas for radio telescope and satellite trackers. Topics include servo system performance, tracking accuracy requirements, closed loop performance, and dynamic performance. The book also takes a look at the application of analog computers to the design of a servomechanism and the use of hybrid computers in servo design. The selection is a valuable source of information for readers interested in servomechanics and feedback control systems.

Table of Contents

  • Contents



    Chapter 1. Basic Servomechanism Theory

    1.1. Introduction

    1.2. The Laplace Transform and Complex Frequencies

    1.3. Transfer Functions

    1.4. The Complex Frequency Plane

    1.5. Block Diagrams

    1.6. Closed Loop Transfer Functions

    1.7. Absolute Stability

    1.8. Frequency Response Design Methods

    1.8.1. NyquistPlot

    1.8.2. Bode Plot

    1.8.3. Nichols Charts

    1.8.4. The Root Locus Method

    1.8.5. Servo Design Using the Root Locus Method

    1.8.6. Routh's Stability Criterion

    1.9. Servo Components

    1.9.1. Error Detectors

    1.9.2. Potentiometer Detectors

    1.9.3. Synchro Error Detectors

    1.9.4. Block Diagram of the Error Detector

    1.10. Servo Compensation

    1.11. Power Amplification

    1.12. The d.c. Servo Motor

    1.13. Gearing and Mechanical Load Resonance

    1.14. Conclusion


    Chapter 2. Preliminary Design of a Large Servomechanism

    2.1. Introduction

    2.2. Performance Specification

    2.3. Steady State and Transient Performance

    2.3.1. Servomechanism Errors

    2.3.2. Steady-state Error Coefficients

    2.4. Selection of Motor and Gear Ratio

    2.4.1. d.c. Servo Motors

    2.4.2. Gear Ratio Selection

    2.4.3. Motor Rating

    2.5. Effects of Disturbances

    2.5.1. Evaluation of Errors from Spectral Density Functions

    2.6. Example: Ward-Leonard Speed Regulator

    2.6.1. Series Compensation

    2.6.2. Feedback Compensation


    Chapter 3. Development of the Servo Design

    3.1. Introduction

    3.2. Mechanics

    3.3. The Motors

    3.4. The Power Stage

    3.4.1. General Requirements

    3.4.2. The Rotary Power Drive

    3.5. The Exciter and Servo Amplifiers

    3.6. The Completed Control Loop and Its Stability

    3.7. Saturation Levels and Designed Non-linearities

    3.7.1. Effects of Saturation on Stability

    3.7.2. The Error Channels

    3.7.3. Saturation Levels

    3.7.4. Coarse Braking

    3.8. Mechanical Resonance

    3.8.1. Resonance Inside the Feedback Loop

    3.8.2. Resonance

    3.8.3. Anti-resonance

    3.8.4. Locked Rotor Resonant Frequency

    3.8.5. The Anti-resonant Rotor Frequency

    3.8.6. The Free Rotor and Load Resonance

    3.8.7. Resonance Outside the Servo Loop

    3.8.8. Cascaded Resonances and Compensation

    3.8.9. Example

    3.9. Additional Factors

    3.10. Summary

    3.11. Appendix


    Chapter 4. Digital Servo Techniques

    4.1. Introduction

    4.2. Speed Control

    4.3. Digital Codes

    4.3.1. Binary Code

    4.3.2. BCD Code

    4.3.3. Gray Code

    4.4. Digital Circuitry

    4.4.1. Logic Functions

    4.4.2. Boolean Algebra

    4.4.3. Bi-stable Memory Unit

    4.4.4. Binary Counters

    4.4.5. 8421 BCD Counter

    4.4.6. 2421 BCD Counter

    4.4.7. Bi-directional Counters

    4.4.8. Digital Subtractors

    4.5. Digital Encoders

    4.5.1. Brush Contact Encodes

    4.5.2. Optical Encoders

    4.5.3. Magnetic Encoders

    4.5.4. Inductive Encoders

    4.5.5. Capacitive Encoders

    4.5.6. Encoder Ambiguity

    4.6. Digital to Analog Convertors

    4.7. Stepper Motors

    4.8. Digital Position Control of a Large Antenna

    4.9. Conclusions


    Chapter 5. Design of Large Antennae for Radio Telescope and Satellite Trackers

    5.1. Introduction

    5.2. Servo System Performance

    5.2.1. Radio Telescopes

    5.2.2. Satellite Trackers

    5.3. Servo Control Input Equipment

    5.3.1. Radio Telescopes

    5.3.2. Other Methods of Polar Coordinate to Alt./Az. Coordinate Conversion

    5.3.3. Input Equipment for Satellite Trackers

    5.4. Choice of Servo Configuration

    5.4.1. Basic Servo Design Philosophy

    5.5. Dynamic Performance

    5.5.1. Zenith Angle Velocity

    5.5.2. Azimuth Velocity

    5.5.3. Accelerations

    5.6. Tracking Accuracy Requirements

    5.6.1. Error Distribution

    5.6.2. Acceleration Error

    5.6.3. Error Due to Tracking Receiver Noise

    5.6.4. Tracking Null Shift Error

    5.6.5. Wind Gusts: Mechanical Deflections

    5.6.6. Servo Bandwidth

    5.6.7. Aerial Inertia

    5.6.8. Motor Rating

    5.6.9. Mechanical Natural Frequency

    5.7. Closed Loop Performance

    5.7.1. Wind Gusts: Servo Errors

    5.7.2. Running into Alignment

    5.8. Commissioning and Testing

    5.8.1. Maximum Acceleration and Velocity Checks

    5.8.2. Response Tests

    5.9. Conclusion


    Chapter 6. The Practical Control System

    6.1. Introduction

    6.2. Practical Servos

    6.2.1. Interference

    6.2.2. Environment

    6.2.3. User Requirements


    6.2.5. Backlash

    6.2.6. Friction

    6.3. On-site Adjustments

    6.3.1. Zero Alignment

    6.3.2. Servo Adjustments

    6.3.3. Performance

    6.3.4. Optimization

    6.4. Measuring Devices and Error Detection

    6.4.1. Potentiometers

    6.4.2. Synchros

    6.4.3. Inductosyn

    6.4.4. Optical Measuring Device

    6.4.5. Digital Error Detectors

    6.4.6. Mechanical Shaft Encoder

    6.4.7. Optical Encoders

    6.4.8. Magnetic Encoder

    6.5. Programming the Input Command to a Servomechanism

    6.5.1. Analog Inputs

    6.5.2. Digital Inputs

    6.5.3. Digital/Analog Convertors

    6.5.4. On-line programming

    6.5.5. Satellite-tracking aerial


    Chapter 7. Application of the Analog Computer to the Design of a Servomechanism

    7.1. Introduction

    7.2. Definition of Analog Computer Functions

    7.2.1. High Gain d.c. Amplifier

    7.2.2. Virtual Earth Concept

    7.2.3. Integration

    7.2.4. Differentiation

    7.2.5. Addition

    7.2.6. Application of the Potentiometer

    7.2.7. Summary of the Basic Analog Computer Operations

    7.2.8. Read-out Facilities

    7.2.9. Programming a Simple Example

    7.3. Preparation of the Problem for the Computer

    7.3.1. Problem Description

    7.3.2. Problem Definition

    7.3.3. Scaling Factors

    7.3.4. Preparing the Computer Diagrams

    7.3.5. Static Check Procedure

    7.4. Simulation of a Position Servomechanism

    7.4.1. System Equations

    7.4.2. Scaled Equations

    7.4.3. Time Scaling

    7.4.4. Problem Check Procedure

    7.5. Design of a Compensating Network

    7.5.1. Simulation of the Compensating Network

    7.6. Non-linear Analog Methods

    7.6.1. Introduction

    7.6.2. Synthesis of Non-linearities

    7.6.3. Limiter

    7.6.4. Coulomb Friction

    7.6.5. Dead Zone

    7.6.6. Hard Limiter

    7.6.7. Half-wave Rectifier

    7.6.8. Hysteresis

    7.7.Non-linear Computer Faculties

    7.7.1. Arbitrary Function Generators

    7.7.2. Generation of Functions of Two Variables

    7.7.3. Particular Function Generators

    7.7.4. Multipliers

    7.7.5. Division

    7.7.6. Relay Comparators

    References and Bibliography

    Chapter 8. Hybrid Computers in Servo Design

    8.1. Introduction

    8.2. The Parallel Hybrid Computer

    8.2.1. Parallel Hybrid Computer Elements

    8.2.2. Analog Section Elements

    8.2.3. Logic Section Elements

    8.2.4. Linkage Elements

    8.3. Applications of the Parallel Hybrid Computer

    8.3.1. Computing the Transient Response of a System for Increasing Values of Disturbance, e.g. Increasing Values of Step Input

    8.3.2. Computing Transient Responses for Increasing Values of Initial Conditions

    8.3.3. Computing Transient Responses for Increasing Values of Parameters

    8.3.4. Boundary Value Problems

    8.3.5. Simulation of Systems which Contain Decision-making Elements

    8.4. Optimization of a Position Servomechanism

    8.4.1. Method of Solution

    8.4.2. Solution on a Parallel Hybrid Computer

    References and Bibliography

    Chapter 9. Servo Amplifier Design

    9.1. Introduction

    9.2. Amplifiers for Large Position Servos

    9.2.1. d.c. Transistor Amplifiers

    9.3. Low Power a.c. Servo Amplifiers

    9.4. Low Power d.c. Servo Amplifiers

    9.5. Power Output Stages

    9.6. Low Level Amplifiers

    9.7. Modern Techniques and Construction

    9.7.1. Silicon Integrated Circuits

    9.7.2. Thin Film Circuits

    9.7.3. Thick Film Circuits

    9.7.4. Micro-welding Techniques

    9.7.5. Potting and Encapsulation

    9.7.6. Multi-layer Printed Circuit Boards and Plated-through Techniques

    9.7.7. Semiconductor Cooling Devices and Vapour-phase Cooling Systems

    9.8. Summary and Future Trends

    9.9 Examples


    Chapter 10. Thyristor Applications

    10.1. Introduction

    10.2. Thyristors, Firing Circuits and Ratings

    10.2.1. Construction and Operation of the Thyristor

    10.2.2. Trigger Requirements

    10.2.3. A Typical Firing Circuit with Phase Control

    10.2.4. Thyristor Ratings

    10.3. Thyristor Power Amplifiers

    10.4. Design of a Thyristor Power Amplifier for a 50 h.p. d.c. Motor Velocity Servo

    10.4.1. System Specification

    10.4.2. Selection of Amplifier Configuration

    10.4.3. Voltage Rating of Thyristors and Protection

    10.4.4. Thyristor Current Ratings and Protection

    10.4.5. Amplifier Design Fuse Protection Calculations

    10.4.6. Steady-state System Design

    10.4.7. Regenerative Braking and Reversing

    10.4.8. Ripple Instability

    10.5. Variable Speed a.c. Motor Drives

    10.5.1. Variable Frequency Control

    10.5.2. Variable Voltage Control

    10.5.3. Modified Kramer Drive


    Chapter 11. Reliability

    11.1. Introduction

    11.2. The Fundamentals of Reliability Theory

    11.2.1. The Exponential Reliability Model

    11.3. Component and Equipment Testing Using Different Approaches

    11.3.1. The Established Reliability Approach

    11.3.2. AGREE Testing

    11.3.3. The "Testing Extra" Approach to Equipment Reliability

    11.4. The Designer's Approach to Equipment Reliability

    11.4.1. Reliability Through Derating

    11.4.2. Derating of Semiconductors

    11.4.3. Derating of Capacitors

    11.4.4. Derating of Resistors

    11.5. The Achievement of Reliability Through Equipment Construction

    11.5.1. Equipment Sealing

    11.5.2. The Use of Plated-through Printed Circuit Boards

    11.5.3. Printed Circuit Connectors to Interconnect Boards

    11.5.4. Wire-wrapped Joints

    11.5.5. Encapsulation of Components or Modules

    11.5.6. Exotherm

    11.5.7. Shrinkage Stress

    11.5.8. The Use of Fillers

    11.5.9. Ingress of Moisture

    11.6. Equipment Reliability Through Component Selection and Examples

    11.7. Equipment Reliability Through Redundancy Techniques

    11.8. Reliability Through the Use of Micro-electronics Techniques

    11.9. Summary of the Approach to Equipment Design




    Other Titles in the Series

Product details

  • No. of pages: 332
  • Language: English
  • Copyright: © Pergamon 1970
  • Published: January 1, 1970
  • Imprint: Pergamon
  • eBook ISBN: 9781483145471

About the Editor

D. R. Wilson

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  • LarryMiller Fri Jun 08 2018

    Modern Practice in Servo Design

    I am 77. This ancient tome uses the math I was taught in college. Guess what, the laws of physics haven't changed even if the method of teaching has! Very practical design examples of real systems from start to finish. Get out your slide rule!