Formation Control for Fixed-Wing UAVs Modeled with Extended Unicycle Dynamics that Include Attitude Kinematics on SO(m) and Speed Constraints

We present a formation-control algorithm for agents with extended unicycle dynamics that include orientation kinematics on SO(m), first-order speed dynamics, and a hard constraint on speed. The desired interagent positions are expressed in a leader-fixed coordinate frame, which is aligned with and rotates with the leader's velocity vector. Thus, the desired interagent positions vary in time as the leader-fixed frame rotates. We assume that each agent has relative-position feedback of its neighbor agents, where the neighbor sets are such that the interagent communication (i.e., feedback) structure represents an undirected and connected graph. We also assume that at least one agent has access to a measurement its position relative to the leader. The analytic result shows that the agents converge to the desired relative positions with the other agents and the leader, and we provide sufficient conditions to ensure that each agent's speed satisfies the speed constraints. We also present an experiment with 3 fixed-wing unmanned air vehicles (UAVs) that demonstrates the leader-fixed formation-control algorithm.