Stiffness Identification And Analysis Of Industrial Robot

In this paper we study the stiffness of a 6DOF vertical-multi-articulated industrial robot. The stiffness model which maps the joint stiffness to cartesian stiffness is established and the properties and physical meaning of the stiffness and compliance matrix is presented.We compute the joint stiffness of the industrial robot through the mechanical structure the transmission components. The transmission system of every joint is divided and the evaluation of component's stiffness is given through its mechanical structure parameters.By converting every component's to the joint, we get the evaluation of the joint stiffness.A experimental method to identify the joint stiffness is presented. The load is exerted on the end point of the robot and the displacement of the end point is measured by a laser tracker.Then the joint stiffness is identified by using the stiffness model and least squares method. We give the modeling and simulation results of flexible joint robot by using MATLAB/SimMechanics toolbox. Then the identification method is practically applied to an industrial robot. The results verify the validity of the identification method.In this paper, we investigate the stiffness index of robot in workspace by using the maximum singularity value of the compliance matrix, and describe the relationship between the direction of force and displacement by using direction stiffness. We also study the effect of joint stiffness and link length on the stiffness index.