Robust Fractional Digital Control of a First Order Plus Integrator Process

• Published in: 2012 IEEE Ninth Electronics, Robotics and Automotive Mechanics Conference pp. 225 - 230
• Main Authors: Sergio, L., Cristian, R. R., Julian, P., Victor, S.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.11.2012
• Subjects: Fractional Calculus - Control of non-integer order - Processes with parametric uncertainty
• ISBN: 9781467350969; 1467350966
• DOI: 10.1109/CERMA.2012.43

In this article an approach based on fractional calculus to control a second order linear process with pure integration at the output is presented. The main contribution of this work is the control strategy, which is a variant of the double loop controller where the proportional outer loop controller is replaced by a fractional derivative one, in order to increase the robustness of the controlled system. A digitalization of the non-integer derivative is performed by a continued fraction expansion and Euler conversion method. Simulation results are shown for a reference tracking and disturbance rejection. In addition, it is compared with a conventional state feedback controller in the presence of uncertainty in the process. Thus, a reasonable response rate is accomplished with no overshoot neither system steady -- state error. These features were kept quite unchanged under a relative uncertainty degree of plus-minus 50% in the plant parameters.