Twice-optimal control design with construction pruning for second order plus time delay systems

To effectively control a class of second-order plus time delay (SOPTD) systems, based on twice-optimal control (TOC) and construction pruning (CP) methods, an SOPTD-TOCCP controller is proposed, which can achieve strong robustness and excellent set-point tracking performance. The TOC controller of the SOPTD is designed based on a classical cascade controller and an extended state observer (ESO). A fast and accurate method is proposed to help engineers obtain the optimal time scale, which is the most critical parameter for regulating control performance. The influence of different parameter sensitivities on SOPTD is studied. In addition, a new robust enhancement method is proposed for SOPTD systems. A construction pruning method for SOPTD systems is proposed to further improve control performance, particularly robustness. Finally, a comparison with other control methods demonstrates that the SOPTD-TOCCP controller is simple, reliable, and versatile and can achieve better control performance.