KINEMATIC ISOTROPY AND THE OPTIMUM DESIGN OF PARALLEL MANIPULATORS

The differential kinematic equations (DKE) of parallel manipulators us ually involve two Jacobian matrices that, depending on the role they p lay in the kinetostatic transformation between the joint and Cartesian variables, are commonly referred to as the forward and the inverse Ja cobians. In this article, we make use of the special structure of thes e Jacobians to define a set of conditions under which a parallel manip ulator con be rendered isotropic. These conditions are general, and pr ovide a systematic method for the optimum kinematic design of parallel manipulators, with or without introducing structural constraints. The application of the proposed conditions is illustrated in detail throu gh a few examples, one of which pertains to the design of a 6-DOF isot ropic parallel manipulator.