AP7.8 A position control system for a DC motor is shown in Figure AP7.8. Obtain the root locus for the velocity feedback constant K, and select K so that all the roots of the characteristic equation are real (two are equal and real). Estimate the step response of the system for the K selected. Compare the estimate with the actual response.

FIGURE AP7.8 A position control system with velocity feedback. R(s) 120 (s+2)(s+17) K 115 Y(s) Position