Singularity-avoidance adaptive interval type-2 fuzzy predefined-time cooperative formation control for multiple QUAVs

Abstract

In this work, the singularity-avoidance predefined-time cooperative formation control for multiple quadrotor unmanned aerial vehicles with preassigned accuracy is investigated. First, an improved fixed-time performance function is introduced in the formation design framework to achieve the convergence constraint on the formation neighborhood tracking error at a specified time. Then, interval type-2 fuzzy logic systems are utilized to approximate the nonlinear function on the controlled vehicles, and a compensation function is presented to weaken the impact of approximation errors and unknown disturbances. In contrast to traditional dynamic surface control schemes, a predefined-time filter is devised to guarantee that the filter error converges within a predefined time. Furthermore, a singularity-avoidance interval type-2 fuzzy predefined-time formation control protocol is developed to achieve the predefined time convergence property of the formation tracking error and to eliminate the difficulty of adjusting the settling time existing in finite/fixed-time control strategies. The boundedness of all signals in the closed-loop system is assured by stability analysis. Finally, the practicality and superiority of the presented control protocol are verified by simulation.