Distributed Attitude Synchronization and Tracking Control for Multiple Rigid Bodies

This paper investigates the distributed attitude synchronization and tracking control for multiple rigid bodies when a common time-varying reference attitude is available to only a subset of the group members. The unit quaternion is used for the attitude representation because of its globally nonsingular property. A decentralized sliding mode observer is presented to obtain an accurate estimate of the reference attitude in finite time. Two distributed attitude coordination control schemes are proposed based on the separation principle. The angular velocity measurements are required in the first control scheme while this requirement is removed in the second case. Both control schemes guarantee all rigid bodies to track the common reference attitude. One important and novel feature of this paper lies in the fact that the proposed distributed control schemes do not require all rigid bodies to have access to the common reference attitude. Simulation results of a scenario of six rigid bodies are presented to demonstrate the performance of the distributed controllers.