Fixed-time coordinated tracking for second-order multi-agent systems with bounded input uncertainties

In this paper, we study the fixed-time coordinated tracking problem for second-order integrator systems with bounded input uncertainties. Two novel distributed controllers are proposed with which the convergence time of the tracking errors is globally bounded for any initial condition of the agents. When relative state measurements are available for each follower, an observer-based distributed control strategy is proposed which achieves fixed-time coordinated tracking for the perturbed second-order multi-agent systems. When only relative output measurements are available, uniform robust exact differentiators are employed together with the observer-based controller which is able to achieve fixed-time coordinated tracking with reduced measurements. Simulation examples are provided to demonstrate the performance of the proposed controllers. (C) 2016 Elsevier B.V. All rights reserved.