Optimal load distribution for two cooperating robots using a force ellipsoid

Abstract

SUMMARY The concept of the force ellipsoid and the manipulability ellipsoid of robotic mechanism is extended to two cooperating robot arms, and the equations of the dual arm force and manipulability ellipsoids are derived. The load distribution problem for two cooperating robots is studied using the concept of the force ellipsoid. The problem is usually underspecified mathematically and a variety of optimal solutions may exist. A new solution approach utilizing the force ellipsoid is proposed in this paper. The load distribution problem is formulated as a nonlinear optimization problem with a quadratic cost function and inequality constraints. The optimality criterion is the minimum energy, and two different cases are considered depending on the presence of the constraints on joint torques.