Innovatory structure design for parallel manipulators: Essential change of design methods

By analyzing the constraint characteristic of each limb which connected the fixed platform with the moving platform of parallel manipulators, the form of limbs can be designed corresponding to certainty kinetic catachrestic form of parallel manipulator. Conventional design method is that one or more actuated joints included in one limb and other joints are passive, then the coefficients of these passive joints baffled the analysis process of inverse/forward kinematics solutions. In this paper, the limbs form of parallel manipulators are classified to two kinds, one is called constraint limb and the other is called actuated limb, that is, the function of constraint limb only provided constraint for parallel manipulator and determine the kinetic characteristic for parallel manipulator, and the function of actuated limb only provided drive for parallel manipulator. The actuated limbs are composed by UCU, SPS and so on. By this innovatory structural design method, analyses of kinematics of the parallel manipulators are simpler than conventional design method.