Safety-oriented robot payload identification using collision-free path planning and decoupling motions

The paper presents a procedure for the identification of the inertial parameters of the payload mounted on the end-effector of a robotic manipulator operating in a collaborative setup. The procedure is therefore designed considering as a primary objective the safe execution of the payload estimation process, in terms of avoidance of physical objects and protected zones within the robot workspace, in which the presence of human operators is allowed and expected. The methods applied in the definition of the proposed operational sequence include a collision-free path planner and a joint trajectory generator that allows the safe execution of specific test motions. In particular, each one of such test motions decouples the effects of all but one inertial parameter of the payload, in order to improve the accuracy of identification. Experimental results on a redundant industrial manipulator demonstrate the feasibility of the proposed identification method.