Formation Transformation Based on Leader-Follower Algorithm

Formation Maintenance Based on Leader-Follower Algorithm

The core of leader-follower method (Zhang, Zhang & Liu, 2008) for formation maintenance is that one or some members are appointed as the leader in a formation composed of a plurality of motive objects,, and the rest is as retinues who follow the position and orientation of the leader at a certain range, thereby keeping various formations (Lin, Hwang & Wang, 2014). The structure of group formation is composed of parallel structure and series structure in the control structure of leader-follower algorithm, as below in Figure 1.

Figure 1.

(a) Parallel structure; (b) Series structure

Leader is centrally the key of the whole group formations influencing the motion and efficiency, whose information such as status, velocity and direction are shared and visible to the its followers (Morbidi, Mariottini & Prattichizzo, 2010). In series structure, all the followers locate their own positions based on the adjacent leader’s controller; in parallel structure, every follower locates its position based on its only leader’s controller. Combining the ISS theory and its derivative form LFS theory (Consolini, Morbidi & Prattichizzo, 2008), the stability of the two fundamental formation models is analyzed and compared. The conclusion is drawn that parallel structure with a single leader is more stable than series structure. Because the formation conversion of troops concludes various leaders, parallel structure is adopted in this paper to carry out the formation transformation.