UIO-Based Prescribed Performance Attitude Tracking Control of UAV

A problem of prescribed performance attitude tracking control of quadrotor UAV with external disturbances is studied in this article. Firstly, for the attitude system with external disturbances, an unknown input observer (UIO) is designed to estimate disturbances accurately. One of the advantages of UIO is that the upper bound of disturbances and their derivatives do not need to be known in advance. Secondly, a control method is designed based on a new predefined-time prescribed performance function (PTPPF), combined with the estimates provided by UIO. The proposed control strategy ensures that tracking error converges to an arbitrarily small residual set within a predefined time. The Lyapunov stability criterion and simulations can verify the effectiveness and superiority of this scheme.