Safeguarding a mobile manipulator using dynamic safety fields

Abstract

This paper presents a novel approach for safeguarding a mobile manipulator. To overcome the shortcomings of state-of-the-art safeguarding techniques, we present a dynamic approach capable of covering different situations and adapting itself to the situation at hand. The proposed approach is based on the continuous dynamic update of a safety field using both exteroceptive and proprioceptive data. The proprioceptive data are the platform velocity vector and the manipulator position; the exteroceptive data refers to the environment in which the mobile manipulator is moving, namely distances to obstacles acquired by laser scanners. The effectiveness of the proposed approach has been validated in an industrial test case scenario in which the robot had to execute a fetch and carry task while safely coexisting with human workers. Experimental results proved that the use of dynamic protection fields allowed the robot to carry out its tasks with a significant reduction (about 50%) of the execution time.