Adaptive task-space cooperative tracking control for manipulators with a desired trajectory estimator and a velocity observer

In this article, the task-space cooperative tracking control problem of robotic manipulators without velocity measurements is investigated, where the desired trajectory of an unknown object is only available to the root manipulator. A cooperative tracking control scheme is presented, which is composed of a task-space desired trajectory estimator, a task-space velocity observer and an adaptive cooperative control law. The estimator is presented to provide the desired trajectory for each manipulator, and the observer is designed to obtain the task-space velocity in the absence of velocity measurements. Based on the estimator and velocity observer, an adaptive cooperative control law is proposed to satisfy task tracking and motion synchronization of manipulators in the presence of kinematic and dynamic uncertainties. Furthermore, strict stability analysis is conducted to prove that the task-space tracking and synchronization errors converge to zero under a connected directed graph. Finally, simulation results are given to demonstrate the superiority of the proposed scheme.