OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in: http://oatao.univ-toulouse.fr/ Eprints ID: 16782 To cite this version: Bolting, Jan and Fergani, Soheib and Biannic, Jean-Marc and Defay, François and Stolle, Martin Discrete Sliding Mode control of small UAS in tight formation flight under information constraints. (Abstract: This paper is concerned with a new control strategy based on discrete sliding mode control of small Unmanned Aerial Systems (UAS) in tight formation flight under information constraints. Tight formation flight enables, among other advantages, significant performance benefits due to wake vortex interactions. A discrete robust control strategy based on the sliding mode approach and a leader-follower scheme is proposed to achieve the desired flight performances while assuming realistic information constraints imposed by limited inter-vehicle communication bandwidth and availability of relative localization sensors. For the discrete sliding mode controller (DSMC), a novel predictive reaching law is proposed and compared to a linear reaching law. This predictive sliding mode control (PDSMC) strategy allows to avoid actuator saturation by solving an optimization problem at each time step. Also, this paper presents a meaningful study and comparison of the two discrete sliding mode control designs and time sampling continuous sliding mode control (TSCSMC). Here, the comparison focuses on the effect of discrete sampling on the control error analytically and in simulation. Effects on mesh stability are evaluated in simulation. Simulation results of a flight scenario with two different sampling frequencies demonstrate the efficiency of the proposed control strategy and show clearly the effect of the sampling time on the formation flight performance of the UAS obtained by the considered control strategies.