High-order LTD Based Predictive LADRC for Uncertain Systems with Time Delay

This paper is concerned with the control problem for a class of uncertain systems with input delay. To accommodate large time delay and various uncertainties, a predictive linear active disturbance rejection control (PLADRC) approach is proposed, where the multi-order Taylor expansion is used for approximating the time-delay link more accurately, and then a high-order linear tracking differentiator (LTD) is introduced to obtain the multi-order derivatives of the virtual control generated by Taylor expansion. The time-domain stability of the closed-loop system is proved that estimation errors and tracking errors can be infinitely small as the gain of a linear extended state observer (LESO) increases. Numerical simulation results show the effectiveness of the modified PLADRC and its superiority over the original PADRC.