Fractional-order PD Control of a Position Servo Using Nelder-Mead Optimization

Fractional-order PD controller was applied in this study to control a position servo. Fractional-order control was known to provide better stability and performance compared to its integer-order counterpart. However, fractional-order PD has more parameters to tune which make it more complicated to design. Nowadays, there are many tuning platforms available which make application of FOPD more convenience. In this study, we applied FOMCON toolbox to tune the FOPD with Nelder-Mead optimization method. Several performance criterions were investigated in this study including IAE and ISE. From the simulation, both criterions produced almost similar response if gain is fixed and only the order was optimized. Further investigation was conducted to evaluate the effect of the order towards output response of a position servo. It was found that, as the order is decreased, the overshoot increased.