A Novel Graphical Design of Fractional‐Order PI‐PD Controller for Blood Pressure Regulation

ABSTRACT This paper introduces a novel tuning approach for a fractional‐order PI‐PD controller, specifically tailored for the blood pressure regulation system. Steps to determine the fractional order of the controller based on the specified phase margin, phase, and gain crossover frequencies are derived in this manuscript. Once the fractional order is obtained, all stability region is plotted on the ‐plane, followed by mapping the boundary corresponding to a desired value of maximum sensitivity. Centroid of the triangular convex region common to all stability regions, and the desired maximum sensitivity function boundary are calculated to obtain the parameters of the inner loop controller. A similar design approach is followed to determine the parameters of the outer loop PI controller. The proposed control strategy demonstrates superior closed‐loop performance over traditional approaches, including model predictive control (MPC), PI‐ID (BFA), and FOPID (GA). Specifically, it achieves substantial reductions in settling time for all the corresponding varying patient sensitivities. For sensitive patients, the improvements are quantified as , , and , respectively. In case of nominal patients, the corresponding reductions for MPC, PI‐ID (BFA) are , , respectively. For insensitive patients, the reductions reach and . Furthermore, the proposed controller achieves enhanced closed‐loop performance, exhibiting the least undershoot and significant reductions in performance measures such as integral absolute error, integral squared error, and integral time absolute error. Simulation results are presented to validate the effectiveness and robustness of the proposed tuning methodology.