Adaptive Distributed Attitude Consensus of a Heterogeneous Multiagent Quadrotor System: Singular Perturbation Approach

Singular perturbations easily cause the problem of high gain control (HGC) of a multiagent quadrotor system (MAQS), that easily excite hazardous high-frequency oscillations in the system states. Without HGC, this work studies the distributed fixed-time attitude consensus control problem of multiple heterogeneous quadrotors in presence of unknown Lipschitz input disturbances and directed topology. First, the second order sliding mode, composed of consensus errors of "slow" Euler angles and "fast" angular velocities, is designed to be two-time-scale. Then, an adaptive super twisting controller is designed to produce an integrated slow-fast control structure, and adjust controller gains in different time scales with respect to the disturbance gradients. On this basis, an $\epsilon$-dependent Lyapunov framework is built for the MAQS on multiple time scales, which provide a rigorous theoretical basis for the fast and robust attitude consensus, and estimate the reaching time subject to singular perturbations. Simulation results on a heterogeneous MAQS consisting of four agents are provided to verify the effectiveness and efficiency of the proposed controller.