Manipulability Measures taking Necessary Joint Torques for Grasping into consideration

This paper presents new manipulability measures to evaluate how much easily the robot manipulates the grasped object, simultaneously taking how much magnitude of joint torque we need to keep grasping into consideration. For the purpose, we use operation range. The operation range is for actuator attached to every joint of robot and provides generable joint torque and velocity and their relation (between generating torque/velocity and addable velocity/torque). While we introduced a manipulability measure using the operation range in our previous paper, it was for a limited class due to large computational effort and we could not evaluate whole space of object velocity and could not consider whole space of external wrench. This paper proposes new manipulability measures which can evaluate whole space of object velocity, taking the effect of external wrench in whole space into consideration. ©2010 IEEE

Softness Effects on Manipulability and Grasp Stability

This paper presents a novel analysis for the effects of softness at the fingertip on the manipulability and stability of grasping. The stability for grasping can be regarded that how much magnitude of external wrench we can balance. We formulate manipulability and the set of generable object wrenches for grasping system, taking deformation of the fingertips into consideration, and show that the increase of the softness decreases the manipulability while it increases generable object wrench. The validity of our analysis is shown by numerical examples. © 2011 IEEE