Distributed coordinated tracking control for multi-manipulator systems under intermittent communications

The distributed coordinated tracking control problem for multiple robotic manipulators under intermittent communications is researched, respectively, with a stationary leader and a dynamic leader in this note. First, three auxiliary variables are introduced and a new distributed coordinated tracking controller is established with a stationary leader, and then, a multi-step design algorithm is proposed to calculate the controller gain matrix and coupling gain. The stability of the controller is further proved, and the range of communication rate is obtained by using Lyapunov stability and switching system theories. Second, with considering a dynamic leader whose joint velocity is unavailable, the distributed velocity estimator is constructed to estimate the unknown joint velocity, and then, a distributed coordinated tracking control strategy-based velocity estimator is designed, whose unknown parameters are resolved by the new multi-step design algorithm accordingly. It is proved that the stability of the controller can be achieved, and the threshold value of the communication rate obtained by utilizing Lyapunov stability theory and LMI technology. Finally, two simulation examples and quantitative comparison are provided to demonstrate the validity and correctness of the obtained methods, and the experimented results show that the distributed tracking controllers of this work can effectively solve the distributed coordinated tracking problem for multiple two-link manipulator systems under intermittent communications.