  This paper deals with the design of Fractional Order Proportional Integral
(FO-PI{\lambda}) controller for the speed control of DC motor. A mathematical
model of DC motor control system is derived and based on this model fractional
order PI{\lambda} controller is designed using stability boundary locus method
to satisfy required gain margin (GM) and phase margin (PM) of the system. Servo
and Regulatory tracking simulation runs are carried out for the speed control
of DC motor. The performance of the fractional order PI{\lambda}
(FO-PI{\lambda}) controller is compared with Integer Order Relay Feedback
Proportional Integral (IO-RFPI) controller. Finally the stability of both
control system is considered.
