Computerised Control
Objectives
The objective of this unit is learning the concept of discrete time dynamic system, including the control design.
There are several derives concepts, namely:
- what is a discrete system, how is characterized and what mathematical representations admits;
- differences between continuous and discrete signals;
- stability and performance;
- discrete time domain and complex frequency domain;
- feedback and closed loop stability;
- application limits of digital control;
- state-space representation;
the student should also know how to:
- convert a continuos system in its discrete equivalent;
- identify the poles and zeros of the transfer function and estimate the performance/stability from its pole-zero diagram;
- plot and analyse Bode and Nyquist diagrams;
- conclude about the stability of a closed loop system from its open loop Bode and Nyquist diagrams;
- compute the eigenvalues of the state-space representation and conclude about the stability;
- design a state variables feedback controller;
additionally, the student acquires the following non-technical competences:
- make a report on experimental work;
- manage time and meet deadlines;
- collaborative team work; abstract and formal reasoning;
- abstract modelling of problems; sub-optimal solutions;
General characterization
Code
10960
Credits
6.0
Responsible teacher
Rui Alexandre Nunes Neves da Silva
Hours
Weekly - 4
Total - 52
Teaching language
Inglês
Prerequisites
Although not mandatory, because of the chaining subjects, it is desirable to have successfully performed before the discipline of Control Theory from the previous semester or equivalent in other school.
All the concepts learned in Control Theory are here transported to the discrete time using the transformation z, in place of the Laplace Transform used in continuous time.
Bibliography
Neves-Silva, Rui, Folhas da disciplina de Controlo por Computador. CLIP
Franklin; Powell; Emami-Naeini, Feedback Control of Dynamic Systems, Addison-Wesley
Teaching method
-Theorectical-practical classes and individual study for knowledge acquisition.
-Practical and laboratory group sessions to test acquired knowledge.
Evaluation method
The approval in the Control Theory UC presents the previous requirement to obtain frequency in the practical component. Obtaining the frequency is conditioned to an average of 9.5 values (in 20) in the evaluation of 3 laboratory works.
The evaluation of the theoretical component is obtained through:
1. The average of the results of two tests performed during the semester; OR
2. The result of an exam in an appeal period (or special period).
For 1. and 2. there is a minimum score of 9.5 values in 20.
The final result of the evaluation will be calculated by the formula:
FR = 25% (Practical Comp) + 75% (Theoretical Comp)
Subject matter
Sampling, control law, discrete transfer function.
Response to impulse and step signals. BIBO stability.
Sampled transfer function of process with the invariant step, discretization of analog controllers.
Mapping between s to z domains. Root locus.
Frequency response, Nyquist and Bode diagrams, permanent error.
Stability criteria.
Control design in the state-space domain.