The parameter study on the grasping characteristics of the humanoid robot hand with a spherical four bar linkage as a finger joint. The humanoid robot hand has one thumb and three fingers, each of which has two spherical four bar linkages, respectively. The humanoid robot hand is 280mm long and less than 2.5kg by weight. The robot hand totally has 13 degree of freedom: one thumb has 4 degree of freedom: each finger has 3 degree of freedom. The spherical four bar linkage was specially designed to rotate like a human finger joint.The robot hand can perform the dexterous motion like a human hand but also the relatively powerful grasping.Two parameters for the grasping characteristics studied in this paper were a diameter of a cylinder to be grasped, the
type of grasping. The contact force of the finger joints
were calculated for four cases. Numerical analysis had
been done in a position control mode by Recurdyn with
Matlab/Simulink.