A novel nonsingular fixed-time control for uncertain bridge crane system using two-layer adaptive disturbance observer

This article aims to design a fixed-time control scheme for a class of uncertain bridge crane systems. Firstly, consider the existence of unknown external disturbances in the bridge crane system working in a complex environment, a novel two-layer adaptive disturbance observer (TADO) based on the principle of equivalent control is designed. Adaptation gain dynamics of TADO parameters can avoid chattering which exists in traditional disturbance observer (DO) with constant gains and enhance the TADO's robustness to different disturbances on the other hand. Secondly, according to the estimated disturbances, a novel continuous nonsingular terminal sliding mode (CNTSM) controller is proposed to achieve the control objective of bridge crane system in fixed time, and a specific expression for the convergence time of the system is provided. The process of rigorous theoretical proof is given by using Lyapunov theory. Finally, numerical simulation and experimental results show the superiority and realizability of the control law proposed in this paper.

Automated summary

This article aims to design a fixed-time control scheme for a class of uncertain bridge crane systems. A novel two-layer adaptive disturbance observer (TADO) based on the principle of equivalent control is designed to handle unknown external disturbances in the complex environment. A novel continuous nonsingular terminal sliding mode (CNTSM) controller is proposed to achieve the control objective of bridge crane system in fixed time based on the estimated disturbances.