Effective envelope method for Stewart platform workspace

The workspace of Stewart platform is the intersection of 6 sun workspaces o f 6 loop chains, so it is important to determine the boundary of the son wo rkspace when locating the boundary of the son workspace. An effective envel ope method is proposed in this paper. Firstly the envelope theory of a fami ly of singular parameter curve surfaces is used to find the envelope surfac es of the son workspace. Then the numerical method is applied to determine the effective envelope surface. And after that the full boundary of the son workspace, which is the envelope of the effective envelope surfaces, is de termined. Finally the workspace can be obtained with a section plane method .