  In this paper, we propose a novel and distributed formation control method
for autonomous robots to follow the desired formation while tracking a moving
target in dynamic environments. In our approach, the desired formations, which
include the virtual nodes arranged into specific shapes, are first generated.
Then, autonomous robots are controlled by the proposed artificial force fields
in order to converge to these virtual nodes without collisions. The stability
analysis based on the Lyapunov approach is given. Moreover, a new combination
of rotational force field and repulsive force field in designing an obstacle
avoidance controller allows the robot to avoid and escape the convex and
nonconvex obstacle shapes. The V-shape and circular shape formations with their
advantages are utilized to test the effectiveness of the proposed method.
