Abstract

This paper presents the analytical stiffness analysis method for a low-DOF planar parallel manipulator. An n-DOF (n＜3) planar parallel manipulator to which 1- or 2-DOF serial mechanism is connected in series may be used as a positioning device in planar tasks requring high payload and high speed. Differently from a 3-DOF planar parallel manipulator, an n-DOF planar parallel counterpart may be subject to constraint forces as well as actuation forces. Using the theory of reciprocal screws, the planar stiffness is modeled such that the moving platform is supported by three springs related to the reciprocal screws of actuations (n) and constraints (3-n). Then, the spring constants can be precisely determined by modeling the compliances of joints and links in serial chains. Finally, the stiffness of two kinds of 2-DOF planar parallel manipulators with simple and complex springs is analyzed. In order to show the effectiveness of the suggested method, the results of analytical stiffness analysis are compared to those of numerical stiffness analysis by using ADAMS.

• Keywords: Low-DOF Planar Parallel Manipulator(저자유도 평면 병렬형 기구),Theory of Reciprocal Screws(역나선 이론),Analytical Stiffness Analysis(해석적 강성해석),Reciprocal Screws of Actuations and Constraints(구동 및 구속 역나선),Joint and Link Compliances(조인트 및 링크 순응성),ADAMS(기구학/동역학 해석 S/W)