MIT16_30F10_lec19

MIT16_30F10_lec19 - Topic #19 16.31 Feedback Control...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Topic #19 16.31 Feedback Control Systems • Stengel Chapter 6 • Question: how well do the large gain and phase margins discussed for LQR map over to DOFB using LQR and LQE (called LQG)? Fall 2010 16.30/31 19–2 Linear Quadratic Gaussian (LQG) • When we use the combination of an optimal estimator (not discussed in this course) and an optimal regulator to design the controller, the compensator is called Linear Quadratic Gaussian (LQG) • Special case of the controllers that can be designed using the sep- aration principle. • Great news about an LQG design is that stability of the closed-loop system is guaranteed . • The designer is freed from having to perform any detailed mechanics- the entire process is fast and automated. • Designer can focus on the “performance” related issues, being con- fident that the LQG design will produce a controller that stabilizes the system. Selecting values of R zz , R uu and relative sizes of R ww & R vv • This sounds great – so what is the catch?? • Remaining issue is that sometimes the controllers designed using these state space tools are very sensitive to errors in the knowledge of the model. • i.e., the compensator might work very well if the plant gain α = 1 , but be unstable if α = 0 . 9 or α = 1 . 1 . • LQG is also prone to plant–pole/compensator–zero cancelation, which tends to be sensitive to modeling errors. • J. Doyle, ”Guaranteed Margins for LQG Regulators”, IEEE Transac- tions on Automatic Control , Vol. 23, No. 4, pp. 756-757, 1978. November 5, 2010 Fall 2010 16.30/31 19–3 • The good news is that the state-space techniques will give you a controller very easily....
View Full Document

This note was uploaded on 02/03/2012 for the course AERO 16.30 taught by Professor Ericferon during the Fall '04 term at MIT.

Page1 / 12

MIT16_30F10_lec19 - Topic #19 16.31 Feedback Control...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online