摘要
With the changes in joint torque and driving state caused by robot postures, the stiffness properties behave differently. However, constant joint stiffness parameters cannot accurately reflect the deformation of different robot postures. To solve this problem, based on the hypothesis of flexible joints, this paper proposes a pose-dependent identification method for joint stiffness. By changing the load at the end of the robot, the laser tracker is used to monitor the slight change of the measuring point on the link near the joint, and the joint deformation monitoring is realized with the analysis of micro displacements. Combined with the external loads monitored by the dynamometer, the change of joint torque is obtained through structural analysis, and then the joint stiffness at a given joint position is identified. Based on the joint stiffness identification results of different joint positions, the joint stiffness is fitted by a polynomial function, and then the varied robot joint stiffness model is obtained. Jacobean transformation and conservative congruence transformation are combined to predict the Cartesian stiffness of the robot. The effectiveness of the stiffness model proposed in this paper is verified by the loading experiments at the end of the robot and robot deformation measurement for milling long aluminum strip.
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单位华中科技大学