Solving reachable workspace of some parallel manipulators by computer-aided design variation geometry

To shape the workspace of some novel parallel manipulators (PMs) is significant. A novel computer-aided design (CAD) variation geometry approach is proposed to shape and solve the reachable workspace of some PMs with three to six degrees of freedom (DOFs). Some basic techniques are described for designing the simulation mechanism and solving the reachable workspace. The simulation mechanisms of some PMs with three to six DOFs are created. When varying the driving dimensions of the active legs in the given extent, the simulation mechanisms vary correspondingly, and the position components of the moving platform are solved automatically. By transferring the position solutions into spatial spline curves in the simulation mechanism, all the boundary surfaces of the workspace can be created and visualized dynamically. Comparing with analytic approaches for solving workspace, the CAD variation geometry approach is simple, straightforward, accurate, and repeatable.