Chapter 13: Digital Control Systems 1 ©2000, John Wiley & Sons, Inc. Nise/Control Systems Engineering, 3/e Chapter 13 Digital Control Systems

©2000, John Wiley & Sons, Inc.

Nise/Control Systems Engineering, 3/e

Chapter 13: Digital Control Systems1

Chapter 13

Digital Control Systems




Figure 13.1Conversion of antennaazimuth positioncontrol system from:a. analog control tob. digital control




Figure 13.2a. Placement of the digital computer within the loop;b. detailed blockdiagram showingplacement of A/D and D/A converters




Figure 13.3Digital-to-analogconver ter




Figure 13.4Steps in analog-to-digital conversion:

a. analog signal;b. analog signal after sample-and-hold;c. conversion ofsamples to digitalnumbers




Figure 13.5Two views of uniform-ratesampling:a. switch opening and closing;b. product of timewaveform andsampling waveform




Figure 13.6Model of sampling with a uniform rectangularpulse train




Figure 13.7Ideal sampling and thezero-order hold




Table 13.1Partial table of z- and s-transforms




Table 13.2z-transform theorems




Figure 13.8Sampled-datasystems:a. continuous;b. sampled input;c. sampled inputand output




Figure 13.9Sampled-data systems and their z-transforms




Figure 13.10Steps in blockdiagram reductionof a sampled-data system




Figure 13.11Digital system forSkill-AssessmentExercise 13.4




Figure 13.12Computer-controlledtorches cut thicksheets of metal usedin construction

© BlairSteitz/Photo Researchers.




Figure 13.13Mapping regions of the s-plane onto the z-plane




Figure 13.14Finding stability ofa missile controlsystem:a. missile;b. conceptual blockdiagram;c. block diagram;d. block diagramwith equivalent singlesampler




Figure 13.15Digital system forExample 13.7




Table 13.3Routh table for Example 13.8




Figure 13.16Digital system forSkill-AssessmentExercise 13.5




Figure 13.17a. Digital feedbackcontrol system forevaluation ofsteady-state errors;b. phantom samplersadded;c. pushing G(s) and its samplers to the right past the pickoff point;d. z-transformequivalent system




Figure 13.18Constant dampingratio, normalizedsettling time, andnormalized peak time plots on the z-plane




Figure 13.19The s-plane sketch of constant percentovershoot line




Figure 13.20Generic digitalfeedback controlsystem




Figure 13.21Digital feedbackcontrol forExample 13.10




Figure 13.22Root locusfor the systemof Figure 13.21




Figure 13.23Root locus for the system of Figure 13.21 with constant0.7 damping ratiocurve




Figure 13.24Sampled stepresponse of thesystem ofFigure 13.21 withK = 0.0627




Figure 13.25a. Digital controlsystem showingthe digital computerperformingcompensation;b. continuous systemused for design;c. transformed digitalsystem




Figure 13.26Closed-loop responsefor the compensatedsystem of Example13.12 showing effectof three differentsampling frequencies




Figure 13.27Block diagramshowing computeremulation of a digitalcompensator




Figure 13.28Flowchart for a second-orderdigital compensator




Figure 13.29Flowchart toimplement




Figure 13.30Antenna controlsystem:a. analogimplementation;b. digitalimplementation




Figure 13.31Analog antenna azimuth positioncontrol system converted to a digital system




Figure 13.32Root locussuperimposed over constant damping ratio curve




Figure 13.33Sampled stepresponse of theantenna azimuthposition controlsystem




Figure 13.34Simplified blockdiagram of antennaazimuth controlsystem




Figure 13.35Closed-loop digitalstep response forantenna controlsystem with a leadcompensator.




Figure 13.36Flowchart for digital lead compensator




Figure P13.1




Figure P13.2




Figure P13.3




Figure P13.4




Figure P13.5




Figure P13.6




Figure P13.7




Figure P13.8




Figure P13.9Simplified blockdiagram for robotswing motion




Figure P13.10Simplified blockdiagram of a floppydisk drive




Table 13.1Partial table of z- and s-transforms




Table 13.2z-transform theorems




Table 13.3Routh table for Example 13.8

Documents

Chapter 13: Digital Control Systems 1 ©2000, John Wiley & Sons, Inc. Nise/Control Systems Engineering, 3/e Chapter 13 Digital Control Systems