KINEMATIC ANALYSIS AND SINGULARITY LOCI OF SPATIAL FOUR-DEGREE-OF-FREEDOM PARALLEL MANIPULATORS

摘要

The kinematic analysis and the determination of the singularity loci of spatial four-degree-of-freedom parallel manipulators with prismatic or revolute actuators are discussed in this article. After introducing the architecture of the spatial parallel four-degree-of-freedom manipulators, algorithms for the solution of the inverse kinematic problem are provided for the two kinds of manipulators considered. Two different methods are presented for the derivation of the velocity equations and the corresponding Jacobian matrices are derived. The numerical determination of the workspace boundaries is then briefly discussed. Finally, the determination of the singularity loci is performed using the velocity equations and examples are given to illustrate the results obtained. Spatial four-degree-of-freedom parallel manipulators can be used in several robotic applications as well as in fight simulators. The determination of their singularity loci is a very important design issue.