A dexterity measure for trajectory planning and kinematic design of redundant manipulators

A novel measure for end-effector dexterity called stochastic manipulability is proposed. This index is based on a kinematic value that is invariable according to the degrees of freedom (DOFs) of manipulator mechanisms and those of task spaces. The harmonic mean manipulability index is improved by normalizing the measure through stochastic consideration of manipulator motion and by adopting the average of joint speeds in place of the sum. This measure can compare the dexterities of manipulators having various DOFs. Therefore, the measure is effective not only for trajectory planning but also for kinematic design by simulation comparisons. The application to 2-DOF and 3-DOF planar manipulators demonstrates the usefulness of the index