Abstract: An improved system model and control algorithm is proposed for the problem existing in the quick converging distributed algorithm for generating arbitrary shape of multiple robots. Robot set partition method based on global communication are discussed in detail, and eath robot selects its following object via some rules. The new model and algorithm can be applied to other cases in which each robot has its own height, target and obstacle. The oretical analysis shows that the improved model an reduce collision among the robots and is a more practical.