Is the closed loop transfer function the same as Hyr?
Submitted by: lars Submitted on: December 1, 2003 Identifier: L10.1 Yes, we call Hyr the closed loop transfer function. Consider the case where we have a feedback control system with a plant P, compensator C and some delay or sensor effect G. The transfer function in this case (which we also call the closed loop TF) is Hyr = PC / (1 + PCG). This can be checked through careful block diagram algebra. In general, for a single negative feedback loop, the closed loop (r to y) transfer function is F/(1+L), where F is the forward path transfer function, and L is the (open) loop transfer function, which includes any blocks on the feedback path. NB: The initial response posted to this question was erroneous. [Back to Top] • What properties does L need to satisfy Bode’s integral formula? Submitted by: lars Submitted on: December 3, 2003 Identifier: L10.1 L needs to be of relative degree (degree of the denominator minus degree of numerator) greater than or equal to 2.
