Coefficient diagram method: Difference between revisions

Revision as of 23:36, 12 June 2006

Revision as of 04:39, 21 June 2006

Line 7:

Modern control methods, like pole-placement, optimal control (LQR) and H¥ , use state-space representation. This representation, especially as the plant degree gets larger, involves complex calculations which require the use of a computer.

Algebraic methods like pole-placement direct method and CDM use polynomial expressions. In this representation, since the numerator and denominator of the transfer function are considered independently from each other, better results can be achieved against pole-zero cancellations. In this approach, the type and degree of the controller polynomials and characteristic polynomial of the closed-loop system are defined at the beginning. Considering the design specifications, coefficients of the polynomials are found later in the design procedure. In algebraic methods, CDM is the one which gives the most proper results with the the easiest procedure. In CDM, design specifications are equivalent time constant (t ), stability indices (yi) and stability limits (yi*). These parameters have certain relations which will be explained later with the controller polynomials (Manabe, 1994).

==See also==