Maximum isotropic force capability maps in planar cooperative systems: A practical case study

Abstract

In robotics, the force capability is defined as the maximum wrench that can be applied (or sustained) by a manipulator. This property is dependent on the robot’s posture, actuation limits and redundancies and, by considering all possible directions of the applied wrench, a polar force capability plot can be generated for a given pose. The concept of isotropic force capability appeared as a subset of the classic force capability and it was formally defined as the maximum magnitude force that a robot can apply or support in all directions according to a posture. A relevant condition which must be studied is when there is load distribution processes between cooperative robots, e.g. when two or more arms are carrying the same load, if the load distribution fails, one of the arms may overload causing structural or material damage during the process. The main objective of this paper is to develop a method to determine the area in the workspace of a cooperative robot composed by two planar serial 3R manipulators which presents the maximum isotropic force capability. The isotropic force capability maps are generated for three different load’s orientations and four working modes and they are compared among themselves.