Task-space coordinated tracking of multiple heterogeneous manipulators   via controller-estimator approaches
  This paper studies the task-space coordinated tracking of a time-varying leader for multiple heterogeneous manipulators (MHMs), containing redundant manipulators and nonredundant ones. Different from the traditional coordinated control, distributed controller-estimator algorithms (DCEA), which consist of local algorithms and networked algorithms, are developed for MHMs with parametric uncertainties and input disturbances. By invoking differential inclusions, nonsmooth analysis, and input-to-state stability, some conditions (including sufficient conditions, necessary and sufficient conditions) on the asymptotic stability of the task-space tracking errors and the subtask errors are developed. Simulation results are given to show the effectiveness of the presented DCEA. 
Ming-Feng Ge, Zhi-Hong Guan, Chao Yang, Chao-Yang Chen, Ding-Fu Zheng,   Ming Chi
cs.SY