A Switched Control Strategy for Avoiding Flip Ambiguities in 3D Formations

Flip ambiguities are a notorious issue with distance-based formation control due to the presence of unwanted equilibrium points in the formation dynamics. We propose a switched control system for preventing these ambiguities in 3D formations composed of tetrahedra. The approach contains a switching strategy that steers the formation of mobile robots towards the desired configuration for all initial positions, excluding certain collocated, collinear, or coplanar cases, by applying the standard distance-based controller and/or rigid-body maneuvers to subformations. Simulations demonstrate that the proposed formation control system can lead to faster formation acquisition and less control effort than an existing method.