  Human hands can not only grasp objects of various shape and size and
manipulate them in hands but also exert such a large gripping force that they
can support the body in the situations such as dangling a bar and climbing a
ladder. On the other hand, it is difficult for most robot hands to manage both.
Therefore in this paper we developed the hand which can grasp various objects
and exert large gripping force. To develop such hand, we focused on the thumb
CM joint with wide range of motion and the MP joints of four fingers with the
DOF of abduction and adduction. Based on the hand with large gripping force and
flexibility using machined spring, we applied above mentioned joint mechanism
to the hand. The thumb CM joint has wide range of motion because of the
combination of three machined springs and MP joints of four fingers have
variable rigidity mechanism instead of driving each joint independently in
order to move joint in limited space and by limited actuators. Using the
developed hand, we achieved the grasping of various objects, supporting a large
load and several motions with an arm.
