Robust adaptive formation tracking of autonomous surface vehicles with guaranteed performance and actuator faults

Abstract

This paper investigates a performance-guaranteed formation tracking problem of autonomous surface vehicles (ASVs) under uncertain environments. Especially, model uncertainties, external disturbances and actuator faults exist simultaneously. Based on graph theory and adaptive techniques, a novel two-layer robust adaptive fault-tolerant formation scheme is developed. In kinematic layer, a transformation is made to get a performance unconstrained problem and an adaptive control strategy is incorporated to stabilize transformed errors. In kinetic layer, two types of robust adaptive fault-tolerant formation controllers, i.e. the fault-based one and the fault-unknown one, are designed for different fault scenarios. These controllers share the same structure of single-parameter updating laws to adjust adaptive parameters. It is shown that: 1) using the proposed formation scheme with either designed fault-tolerant controller, desired formation configurations of ASVs are achieved if the interaction topology is connected and control parameters satisfy given conditions; 2) prescribed formation tracking performance can be ensured and all error signals are guaranteed to be uniformly ultimately bounded; 3) a trade-off between two designed controllers exists, that is although the assumption for fault-unknown controller is weaker, larger control parameters are required to behave like fault-based one. Simulations and comparisons are provided to illustrate the effectiveness of theoretical results.