A closed-loop speed control system is subjected to a disturbance due to a load, as shown in Figure DP4.1. The desired speed is vd1t2 = 100 rad>s, and the load disturbance is a unit step input Td1s2 = 1>s.

Assume that the speed has attained the no-load speed of 100 rad/s and is in steady state.

(a) Determine the steady-state effect of the load disturbance, and (b)

plot v1t2 for the step disturbance for selected values of gain so that 10 … K … 25. Determine a suitable value for the gain K.

FIGURE DP4.1 Speed control system. w(s) Desired speed Controller K S Load disturbance T(s) G(s) 1 w(s) s+4 Actual speed