ON THE WORKSPACE OF GENERAL 4R MANIPULATORS

The workspace of a general 4R manipulator is analyzed by examining its cross-section evaluation to investigate its main characteristics and how they are affected by link parameters. An algebraic formulation is deduced for a workspace boundary of a general 4R manipulator from the geometry of an envelope generation. This algebraic formulation is also useful for direct computation of the workspace volume and for detection of holes and voids, in addition, both analysis and synthesis criteria are deduced from this algebraic formulation, taking into account the geometric nature of the 4R manipulator workspace as a volume of revolution. Several numerical examples show general geometries of 4R manipulator workspaces.