RST controller

The block diagram of a two degree of freedom RST controller is as follows:

where B/A is the plant model and R,S and T are the polynomials of q-1.

R(q-1) = r0+r1q-1+...+rnrq-nr

S(q-1) = 1+s1q-1+...+snsq-ns = 1+q-1S'(q-1)

T(q-1) = t0+t1q-1+...+tntq-nt

The control input u(t) is computed by:

u(t)=-S'(q-1)u(t)+T(q-1)r(t)-R(q-1)y(t)

The main advantage of this representation (RST form) is that all type of controllers can be represented by an RST controller. For example, a controller K=R/S in feedforward with unit feedback is equivalent of chossing T=R and a controller K=R/S in feedback is equivalent of chossing T=S and etc.

See: Closed loop identification module .

Help topics.

(file rst.htm)