# Digital Control

Master's degree in Electrical Engineering (specialization in Control and Industrial Electronics)

6 ECTS; 1º Ano, 1º Semestre, 28,0 T + 28,0 PL + 5,0 OT + 2,0 O

Lecturer

Prerequisites
Not applicable.

Objectives
The objectives are to provide knowledge on several digital control systems structures; and to be able to design and analyse digital control designs. Be able to discretize a continuous-time plant to design a digital control system.

Program
1 - Introduction to digital control: discrete systems analysis; computer controlled systems.
2 - Z-transform and Inverse Z-Transform.
3 - Discrete systems analysis using Z-transform;
4 - Sampling: ideal sampler; sample and hold. Mapping between the s-plane and the z-plane.
5 - Digital controller design by numerical approximation of an analog controller. Digital PID controller.
6 - Direct design of digital controller: methods; choice of the sampling period.
7 - Stability of digital control systems: stability, Routh modified criterium, Jury criterium, steady state error, root
locus in the z-plane.
8 - State-space models: discretization of continuous-time state-space equations.
9 - Controllability, attainability and observability.
10 - State-space design: design of state feedback and output feedback control; Ackermann's formula; pole
11 - Introduction to estimators.

Evaluation Methodology
Exam (50%) and practical assignments (50%). The student must obtain a minimum grade of 8 marks (on a scale of 0 to 20) in the exam and a minimum grade of 9.5 marks (on a scale of 0 to 20) in the practical assignments. The average of the two components must be greater than or equal to 9.5 marks (on a scale of 0 to 20).

Bibliography
- Wittenmark, B. e Astrom, K. (1997). Computer-controlled systems: theory and design. USA: Prentice-Hall
- Ogata, K. (1994). Discrete-time Control Systems. USA: Prentice-Hall
- Franklin, G. e Workman, M. e Powell, J. (1998). Digital Control of Dynamic Systems. USA: Addison-Wesley

Method of interaction
Lectures incorporating illustrative cases. Theoretical-practical lessons focused on concept application and problem-solving.Practical exercises.

Software used in class