Microcontroller Implementation of a Multivariable Fractional Order PI Controller

Fractional order calculus has been used intensively to control various types of processes. The main approaches towards fractional order controllers focus on the single-input-single-output systems. The general design procedure consists in a frequency domain specification of various performance criteria followed by optimization routines. The implementation issues regarding fractional order controllers are based on Oustaloup approximations and are centered on SISO processes. The present paper addresses the problem of implementing on a microcontroller a fractional order multivariable controller for time delay processes. The paper presents a tuning algorithm for determining the parameters of the multivariable fractional order controller and the implementation issues. The multivariable time delay process is implemented in Matlab Simulink environment. The experimental results show that the fractional order multivariable controller implemented on a simple microcontroller provides similar results to that obtained by simulation, even under uncertainty conditions.