Predefined-time tracking control of unmanned helicopter:a time-varying gain disturbance observer-based approach
HAO Chuanmin
CAO Teng
GUO Baodi
WANG Yujie
YANG Shaohua
Abstract：This paper proposes a predefined-time tracking control scheme to address the trajectory tracking problem of unmanned helicopters subject to time-varying disturbances.To overcome the dependence of finite-time control on initial states and the conservatism of fixed-time control in estimating the convergence time upper bound,the predefined-time theory is introduced.This approach enables the precise presetting of the system convergence time using a single control parameter,eliminating the need for complex parame-ter tuning.First,a nonlinear dynamic model of the unmanned helicopter is established,and a time-varying gain disturbance observer is designed to estimate unknown time-varying disturbances.Second,utilizing a disturbance compensation mechanism,a sliding mode-based predefined-time controller is developed to en-sure that the helicopter's attitude and altitude strictly converge to the desired trajectory within a preset time window,independent of the initial system states.Rigorous analysis based on Lyapunov stability theo-ry verifies the predefined-time convergence characteristics of the closed-loop system.Finally,comparative simulation experiments demonstrate that the proposed strategy offers superior performance over existing methods in terms of convergence time controllability,tracking error suppression,and steady-state robust-ness.
Keywords：unmanned helicopterdisturbance observerpredefined-time controlsliding mode controltracking control
Publication Date：2026-06-25
Online Publishing Date：2026-08-28(First online date of this platform, not the publication date of the document)
Pages：12( 317-327,373 )