Kinematic control of redundant robots with guaranteed joint limit avoidance

•A novel kinematic control signal guaranteeing joint limit avoidance is proposed.•In sensor driven tasks it generates feasible paths to the target.•With planned task trajectories it can act as a null-space velocity.•Smooth joint trajectories and accurate target reaching are achieved.•Experimental results with a KUKA LWR4+ manipulator demonstrate its performance.

A novel approach for addressing the inverse differential kinematics of redundant manipulators in the presence of hard joint position constraints is presented. A prescribed performance signal for joint limit avoidance guarantees is proposed that can be utilized with both planned and on-line generated trajectories. In the first case, it is a null space velocity for the primary task velocity mapping while in the second case, it modifies the generated reference by acting on the whole velocity space producing a feasible path to the target. Experimental results utilizing a 7DOF KUKA LWR4+ arm demonstrate the performance of the proposed kinematic controller.