  This letter proposes two finite-time bearing-based control laws for acyclic
leader-follower formations. The leaders in formation move with a bounded
continuous reference velocity and each follower controls its position with
regard to three agents in the formation. The first control law uses only
bearing vectors, and finite-time convergence is achieved by properly selecting
two state-dependent control gains. The second control law requires both bearing
vectors and communications between agents. Each agent simultaneously localizes
and follows a virtual target. Finite-time convergence of the desired formation
under both control laws is proved by mathematical induction and supported by
numerical simulations. 10.1109/LCSYS.2021.3088299
