Desired Workspace-Based Structural Analyses of a Parallel Mechanism with Sub Closed-Chains for 6-DOF Controller.

The realization of desired workspace is vital for structural design of a 6-DOF controller. For this intention, an ELM modeling-based analyzing method of critical rod scales of the 6-DOF controller mechanism is presented in this paper. Firstly, kinematics inverse solution of the parallel mechanism with sub closed-chains for the 6-DOF controller is described, and then its workspace is analyzed by a numerical researching based on this solution. Secondly, the relationships from the workspace volume and its 3 projective areas to their corresponding critical rod scales (l(4)-l(7)) of this mechanism are constructed by ELM modeling method. With desired values of its workspace volume and 3 projective areas being the input vector, the rod scales above are calculated by the established ELM model. Ultimately, the model reliability is verified by the agreement between the workspace volume and its 3 projective areas based on the calculated rod scales and their desired scales. Furthermore, combined with the designer judgment onto the actual workspace shapes, the proposed method can calculate critical rod scales for parallel mechanism with sub closed-chains to meet the designer expectations for actual use of a 6-DOF controller.