Design and implementation of fractional order (PID mu)-D-lambda controller for thermal process using stability boundary locus

Fractional order control is a new technique that uses fractional order calculus in the control applications. By introducing the fractional terms in basic control equations, we can achieve more satisfactory results with high precision in the system response, like less overshoot, reduced settling time, less steady state error, etc. It gives better control over the operating region with the help of fractional terms. Initially, the range of system stability is determined based on a novel graphical method, stability boundary locus. This method is used for tuning the fractional order controller parameters, K-p, K-i and K-d for the specified gain and phase margins. Stability of the system with controller is checked based on bode plot. This novel graphical method, stability boundary locus, in frequency domain uses less mathematical calculations and gives an idea about the system stability regions. Using this method, the gain and phase margin specification can be attained very easily without complex numerical analysis.