Distributed observer-based tracking of multi-agent systems with bounded input amplitudes and rates

This work solves the distributed tracking problem for multi-agent systems with bounded inputs over directed networks. Unlike existing results focusing only on the input amplitude saturation, both input amplitude and input rate saturation are taken into account, which are more challenging due to the coupled evolutions of input amplitudes and input rates. Firstly, relative disturbance observers are developed using relative state measurements to estimate the relative disturbances, where the estimation errors converge to zero within a finite time horizon. Subsequently, distributed tracking error observers are proposed by means of a novel bounded function to estimate the tracking errors, where the estimation errors will converge to zero. Then, an observer-based saturated control strategy is designed to achieve the distributed tracking objective. Finally, simulations of DC-DC buck converters tracking and vehicles formation are provided to verify the effectiveness of the control scheme.