Institut Universitaire de Technologie
MC-AS21 Digital control systems design
Semester : 4 Course hours : 30
Course objectives :
Modelling, analysis and control of linear discret-time systems to improve their dynamic performances.
Course outcomes :
Ability to implement an analog controller on a digital computer.
Ability to discretize a continuous-time plant to design a digital control system.
Ability to model or to identify a discret-time system with a linear input-output relation..
Ability for designing quickly a control law providing
performances requirement according to stability,
steady state error, settling time response and disturbances rejection.
Key words :
Digitizing analog controller, sampling, sampling period, zero-order hold, analog-to-digital converter,
digital-to-analog converter, sampled-data system, difference equation, discrete time system, time delay
operator, z-transfer, stability, error, settling time, time finite response, anti-wind up, pole placement, root
locus, direct design method of Ragazzini, Smith predictor, identification, least-squares method.
Topics covered :
Additionnal techniques of control design for continuous-time systems :
Raggazini method, Graham-Lathrop optimal controllers.
Poles placement using the roots locus design method,construction of the roots locus, closed-
pole location and performances.
Introduction to digital control : interfaces plant computer, sample and hold, DAC, ADC.
Numerical approximation of an analog controller and implementation of a digital controller.
z-ransfers operators defined through an operational coding of linear difference equations. DC gain.
Direct design of digital control, association of transfers, poles et zeros of sampled-data systems.
Analysis of sampled-data systems : stability, Routh modified criterium, Jury criterium, steady state
error, time finite response, time and frequency response of elementary systems as transport delay.
Analyse of specification sheets, choice of a second order model, choice of the sampling period.
Digital PID controller and anti-wind up techniques.
Digital control methods : pole placement using root locus in the z-plane, direct design method of
Ragazzini and Smith predictor.
Parametric identification of a discret linear model using the least suqares method.
Frédéric Rotella, Irène Zambettakis, Automatique élémentaire, de lanalyse des système à la régulation
Hermès Lavoisier, 2008.
Frédéric Rotella, Irène Zambettakis, An automatic control course without the Laplace transform, e-STA, vol.4,
n° 4, 2008.