“…Each vehicle has its own relative position in the body and tracks the desired trajectory which is translated from the desired motion of the rigid body (Askari, Mortazavi, & Talebi, 2013;Li & Liu, 2008). The standard artificial potential field (APF) approach is based on applying the negative gradient of an artificial potential function as control inputs to drive the overall formation to convergence (Do, 2007;Krick, Broucke, & Francis, 2009;Xue, Yao, Chen, & Yu, 2010). Further, a unified optimal control approach consisting of formation control, trajectory tracking, and obstacle avoidance was presented by J.…”