Geared Dc motors can be controlled by many controllers which may include the conventional PID controllers and various other techniques. The sliding mode control is one of the good controllers which can be used for conditions like disturbances and parameter variations. The system responses are compared when PID controller is applied to the system. SMC methods yield nonlinear controllers which are robust against unmodeled dynamics and, internal and external perturbations. Also, due to system uncertainties that can lead to chattering phenomena in control law which can excite non-modeled dynamics and may damage the process, different approaches, like intelligent techniques, are used to minimize these effects. In this paper, the FL will be considered in the design of SMC. Also, a PID will be used in the outer loop in the control law then the gains of the sliding term and PID term are tuned on-line by a fuzzy system, so the chattering is eliminated and response of system is improved against external load here. Presented simulation results make sure that the above proposal and demonstrate the performance improvement to the example of DC motor. The results obtained with SMC with changed gains are compared with the traditional PID controller and fuzzy sliding mode controller. The advantages and limitations of each method are discussed.

1. Ogata K. , "Modern control Engineering". New Jersey, Prentice-Hall, 1990.
2. EL Sharkawi M and Huang C. , "Variable structure tracking of DC motor for high performance applications". IEEE Trans. on Energy Conversion, V 4, 1989, pp. 643-650.
3. Ghazy M. , "State of the art control techniques used in servo DC motor applications". Report: Elect. Dep. , Helwan University, Egypt, 2002 .
4. M. E. Haque, and M. F. Rahman," Influence of stator resistance variation on controlled interior permanent magnet synchronous motor drive performance and its compensation", IEEE Trans. On Energy Conversion , 2001, pp. 2563-2569.
5. Ciro Attaianese, Vito Nardi, Aldo Perfetto and Giuseppe Tomasso. . Vectorial torque ontrol: A novel approach to torque and flux control of induction motor . , IEEE Trans. On Indust. Appl, Vol. 35, No. 6, December 1999, pp. 1399-1405.
6. M. F. Rahman, E. Haque, and L. Zhong, . Problems associated with the direct torque control of an interior permanent magnet synchronous motor drive and their remedies. , IEEE Trans. On Indust. Electronics. , Vol. 51, No. 4, August 2004, pp. 799-908.
7. A. M. Abdel Ghany and Ahmed Bensenouci, "Improved Free-chattering variable-structure for a DC servomotor position control". 3rd Saudi Technical Conf. , V 2, December 2004, pp. 21-30.
8. Orges Gjini, Takaynki Kaneko and Hirosh Ohsawa. "A new controller for PMSM servo drive based on the sliding mode approach with parameter adaptation". IEE Trans. On IA, V 123, No. 6, 2003, pp. 675-680.
9. Astrom K. J. and Hagglund T. . , "PID controllers: theory, design and tuning". Instrument Society of America, 2nd edition, 1995.
10. Kristiansson, B. and Lennartson, B. , "Robust and optimal tuning of PID controllers", IEE Proc. Control theory and application, V 149, 2002, pp. 17-25

Pid Controller Sliding Mode Controller Fuzzy Sliding Mode Controller Geared Dc Motor.