Distributed finite-time velocity-free robust formation control of multiple underactuated AUVs under switching directed topologies

Abstract

This paper proposes a distributed finite-time velocity-free robust formation control scheme for multiple underactuated autonomous underwater vehicles (AUVs) under switching directed topologies in the presence of uncertain dynamics and unknown time-varying external disturbances. Here, a novel finite-time velocity observer is created for each AUV to estimate its neighbors’ velocities within a finite time so that only its neighbors’ positions need to be transmitted, which reduces the communication burden between AUVs. Then, a super-twisting extended state observer is constructed for each AUV to estimate its total disturbances lumped by the uncertain dynamics and the unknown time-varying external disturbances, whose estimation errors can converge to zero within a finite time. Further, a distributed finite-time velocity-free robust formation control law is proposed incorporating the above into the nonsingular terminal sliding mode technique. Theoretical analysis and simulation results indicate that the proposed formation control law can make the multiple AUVs achieve the desired formation pattern while guaranteeing the formation errors converge to zero within a finite time.