Velocity free leader-follower formation control for autonomous underwater vehicles with line-of-sight range and angle constraints

This paper investigates the problem of leader-follower formation control of underactuated autonomous underwater vehicles (AUVs), where the Line-of-sight (LOS) range and angle are constrained. An observer is involved to estimate the leader velocity in finite time with zero error, alleviating the need of communications between the AUVs. Based on the finite time observer, the formation controllers of the AUVs are designed using time-varying In-type barrier Lyapunov function (BLF) method, which can guarantee that the resulting AUVs formation control system is uniformly ultimately bounded. To deal with the problem of explosion of differentiation terms in backstepping control, we introduce a command filter to realize the derivative of virtual variables. At the same time, a compensating signal is constructed (based on the auxiliary system technique) to compensate for the errors of the command filter. Simulation results have demonstrated the effectiveness of the proposed method. (C) 2019 Elsevier Inc. All rights reserved.