“…However, a real robot is never a point, and therefore collision avoidance cannot be negligible when several robots work together in a region. Collision avoidance itself, especially for nonholonomic mobile robots, is a challenging problem (see Kan, Dani, Shea, &Dixon, 2012, Mastellone, Stipanović, Graunke, Intlekofer, &Spong, 2008 andreferences therein). Designing a totally distributed and mathematically provable bearing-only collision avoidance algorithm remains an unsolved problem and we are still working on it.…”