Research On Design Of Flexture Jointed Stewart Platform

Optical systems are widely used in precision engineering areas such asoptical microscopy, semiconductor manufacture and space observation. Toensure accuracy of the optical systems, the optical elements should notonly have low surface shape error but also to be accurately positioned. Inthis thesis, design of flexure jointed Stewart platform or hexapods (FJH) isresearched under the application background of optical elements precisepositioning. The main works are as following:Firstly, each leg of FJH is treated as6degrees of freedom serial robot.Coordinates are established for each leg based on Denavit–Hartenbergrepresentation method. Inverse kinematics is solved for each leg. Based onthe principle of virtual work inverse dynamics of the FJH is developed.The relationships of flexure stiffness, workspace and actuator forces can beexplored based on inverse dynamics of FJH. The kinematics and dynamicof FJH is the basis of the design research.Secondly, based on inverse kinematics and inverse dynamicsdeveloped previously, design target of flexure hinges and actuators arecalculated, including but not limited to displacement capacity and stiffnessof the flexures, range of motion and output force of the actuators. Flexuresand the actuator are designed accordingly to ensure the designed FJHmeets requirements of workspace, resolution and load capacity.Lastly, the performance of the designed FJH is analyzed. Stiffnessmatrix of the whole structure is evaluated utilizing stiffness transformationmatrix and the modal characteristic is analyzed using FEM software.Stiffness matrix of the whole structure is verified by comparing withresults analyzed by FEM software.