Study on the static stiffness of the parallel flexure joint robot

The parallel flexure joint robot is a micromanipulator with ultra-precise positioning ability. As using the un-normal pairs, its positioning accuracy under load mainly depends on static stiffness. Therefore, it is very important for the designer to be able to predict the stiff property of such micromanipulator. In this paper, the mapping between the end-effector's perturbation displacement of position and attitude and the micro deformation of the flexure joints was derived through the transformations of a series of coordinate systems; The static stiffness model was established by the principle of virtual work; The static stiffness properties of the parallel flexible joint robot was discussed. An example was given and the results show the model reveals that both transmission stiffness and the flexible joint stiffness influence the static stiffness and can be used to guide the optimal design of the structure.