Question

The below figure represents:

(a) Lead network

(b) Lag network

(c) PI controller

(d) PD controller

I had been asked this question in an interview.

Question is taken from Differential Equations of Physical Systems and Dynamics of Robotic Mechanisms in portion Mathematical Models of Physical Systems of Control Systems

Answer 1

Right option is (b) Lag network

To explain I would say: The equations of performance are

B1(dX1/dt-dX2/dt)+k1(X1-X0)=k2X0

T=k1(1+B1s/K1)/k1+k2(1+sB1/k1+k2)

X0(s)/X1(s)=1/a(1+aTs/1+Ts).