Task-oriented rigidity optimization for 7 DOF redundant manipulators

David Busson (1) , Richard Bearee (1) , Adel Olabi (1)

1 LISPEN - Laboratoire d’Ingénierie des Systèmes Physiques et Numériques

In this work, redundancy resolution has been employed to increase the Cartesian mechanical rigidity of 7 DOF robot manipulators during tasks requiring stiff interactions with the environment (e.g. milling or drilling). The Cartesian static stiffness of the end-effector for a given joint configuration is deduced from an identified joints stiffness model. The Cartesian reflected rigidity evolution over an analytically computed self-motion of the manipulator shows significant variations that clearly highlight the need to select the right set of joint angles among the possible ones. A global optimization scheme of the redundant DOF is proposed to determine the stiffest robot configurations for a given pose of the end-effector. An experimental study on 7 DOF KUKA LBR iiwa then shows the relevance of the proposed approach in finding the redundant robot joint angles that optimize this rigidity criteria.

Mots clés: Kinematic redundancy; Joint stiffness; Cartesian rigidity; 7 DOF anthropomorphic robot arm

Domaines: Automatique / Robotique

David Busson, Richard Bearee, Adel Olabi. Task-oriented rigidity optimization for 7 DOF redundant manipulators. 20th IFAC World Congress, Jul 2017, Toulouse, France. pp.14588-14593. ⟨hal-02362128⟩