P6.9 A cassette tape storage device has been designed for mass-storage [1]. It is necessary to control the velocity of the tape accurately. The speed control of the tape drive is represented by the system shown in Figure P6.9.

(a) Determine the limiting gain for a stable system.

(b) Determine a suitable gain so that the percent overshoot to a step command is P O. . = 5%.

FIGURE P6.9 Tape drive control. Power amplifier K R(s) s+ 100 Motor and drive mechanism 10 (s+20) Y(s)