Digital Fractional Order PID Controller Design And Realization

In this paper a special kind of PID controller has been designed and implemented which is called fractional order PID (FOPID) controller whose derivative and integral are fractional rather than integers. The FOPID controller has five parameters which have been tuned by using an intelligent particle swarm optimization (PSO) algorithm by minimizing the fitness function given as integral of time weighted absolute error (ITAE). The digital fractional order PID (DFOPID) controller in discrete time with suitable sampling period has been attained utilizing special approximation method called continued fraction expansion (CFE) that lead to convert the s domain transfer function into z domain using MATLAB tools. As a case of study the DFOPID controller has been designed and realized by software in C language on PIC microcontroller for DC motor as a position control. The results showed software fulfillment of DFOPID, with alike time domain performance of closed loop system for both continuous and discrete.