Subject Code: EE4L005 Subject Name: Digital Control Systems L-T-P: 3-1-0 Credit: 4
Pre-requisite(s): Control Systems
Introduction: Basic structure of digital control systems, Sampled-data control systems, DAC, ADC, Sample-and-hold operation, Sampling and reconstruction: ZOH and frequency domain considerations, Shanon’s sampling theorem, Frequency spectrum; Transform Analysis of Sampled-Data Systems: Linear difference equation, Pulse response, Z-transform: review of properties and theorems, Inverse Ztransform, Relationship between z-plane and s-plane, Transform pairs; Discrete-Time System Modeling: Pulse transfer function, z-transfer function, discrete-time system with cascaded elements separated and not-separated by a sampler, Pulse transfer function of ZOH, Closed-loop systems, Characteristic equation, Sampled signal flow graph, Mason’s gain formula; Stability Analysis: Introduction, Theorems, Stability tests: Bilinear transformation method and Jury’s test, Performance specifications in time domain, Prototype second order system and response analysis, Steady state error analysis, Root loci; Frequency Domain Analysis: Introduction, Polar Plot, Nyquist stability criterion, Bode plot, Gain and phase margin, Closed-loop frequency response, z-domain equivalents of s-domain transfer functions; State Space Analysis: State equations and state transition equations with S/H devices, Relationship between state equations and transfer functions, Diagonalization, Computation of state transition matrix, State diagram, Decomposition of transfer functions, Realization of digital filters, Controllability and observability; Pole Placement Design and State Observers: Introduction, State feedback, Pole assignment by state feedback, Ackerman’s formula, Deadbeat control, State observers, Deadbeat observer, The Separation Principle, Reduce order observer; Design of Digital Compensators: Frequency response based designs: Lead compensator, Lag compensator, Lead-lag compensator, Design using root locus plots: Lead compensator, Lag compensator, Lead-lag compensator, Digital PID controller design.

Text/Reference Books:
  1. 1. B. C. Kuo, “Digital Control Systems”, 2nd Edition, Oxford University Press, 2012.
  2. 2. K. Ogata, “Discrete-Time Control Systems”, 2nd Edition, Prentice Hall, 2009.
  3. 3. Charles L. Phillips , Troy Nagle , James Brickley, “Digital Control System Analysis and Design”, Prentice Hall, 2014.
  4. 4. M. Gopal, “Digital Control Engineering”, New Age International Publishers, 1996.