Translation Stiffness Calculation for Serial Robots

The advantages of serial robots in flexibility, reach area and cost are considerable, while the application in many industrial fields is limited by the shortage of stiffness. Translation stiffness is a part of Cartesian stiffness, it determines the displacement of robot's end-effector when the torque is negligible. This paper proposes a calculation method of translation stiffness in the effective working space of serial robot based on traditional kinematic model and joint stiffness. With groups of measuring data of robot's end-effector displacements and corresponding external forces in different configurations, a L2-norm minimization function is used to identify joint stiffness of robot, and configurations are chosen efficiently through Design of Experiment(DoE) method. Translation stiffness of other configurations are measured to validate the calculation method.