Time parametrization of prioritized inverse kinematics based on terminal attractors

Classical prioritized inverse kinematics (PIK) allows to generate admissible trajectories for redundant robotic systems according to a prioritized finite set of kinematic tasks to simultaneously handle multiple posture constraints. In this paper, we propose a novel regulation scheme that permits to define terminal attractors (TA) at each priority level for satisfying an additional constraint which is the final time. TA were first introduced in the context of movement neuroscience for studying the targeting problem in reaching movements. Based on the underlying properties of TA, we extend PIK methods for achieving desired time convergence of each task while guaranteeing smooth transitions between active and inactive tasks during execution. The proposed scheme is illustrated in simulation with branched robotic manipulators and verified with a real redundant robotic arm.