Kinematic Modelling of a Stewart-Gough Platform with Modified Cardan Joints

This study introduces the design and features of a fixturing mechanism based on a passive Stewart-Gough platform, called hexapod, along with its kinematic modeling. The proposed hexapods are used as versatile fixturing elements for holding workpieces in industrial production lines. While based on the original design proposed by Stewart and Gough, our design incorporates the use of custom-made Cardan joints at the platform’s joints to enhance its capacity for bearing loads. This modification necessitates adjustments in the kinematic model of the platform, which must be accounted for in the kinematic analysis. The paper outlines the kinematic model for the proposed hexapods and presents a numerical method for determining both the direct and inverse kinematics of the system.