The course aims at making the students able to: - understand the basics of feedback control for a linear time-invariant continuous-time and discrete-time dynamical system; -analyse the closed loop stability even in front of disturbamces or parametric perturbations; - understand the performances of a control system, both in the time and in the frequency domani; - perform the design of a feedback controller for a linear time-invariant, time-continuous system, with the possibility to derive a digital implementation; - perform the controller design via standad PID controllers
1. Introduction to control systems; Characteristics of the response for linear systems of the first and the second order in the time domain: time constant, response time, rising time, settling time. relation between the response characteristics and the pole-zero position in the s plane. Characteristics of the frequency response for first and second order systems, cut-off frequency, band, resonance modulus. Non minimum phase systems. Polar plots.
2. Open and closed loop control. feedback influence on the sensitivity to parameter variations, disturbance both in the direct chain and in the feedback path, and to the band width for a linear system. Steady state accuracy for a feedback system for input signals like step, ramp, parabolic ramp; classification of control systems in "types". Stability analysis via the Nyquist criterion. Gain and Phase margins.
3. Performances of a control system: static and dynamic performances. Transformation of time domain to frequency domain performances. Frequency response design using lead and lag elementary controller network using Bode diagrams. Realization of controller networks via operational amplifiers. Standard PID controllers: empirical and analytical tuning strategies.
4. Realization of controller networks via operational amplifiers. Standard PID controllers: empirical and analytical tuning strategies.
5. Relation between the s plane and the z plane. Bilinear transformation. Discretization and reconstruction of a signal. Sampling theorem. Performances of a discrete control system. Design of a discrete control system via translation of a continuous controller.
6. Exercitations. The practical lessons are focussed ad deepening of theoretical aspects using key exercises, using the Matlab tool. particular examples are related to the frequency response design and root locus design.
1. Norman Nise, Controlli Automatici,,CittàStudi;
2. Dorf, Bishop, Controlli Automatici, Pearson