Industrial robots are promising and competitive alternatives for performing machining operations due to their advantages of good mobility, high flexibility and low cost. However, the application of industrial robots in the field of high-precision machining such as grinding is hugely limited by the characteristic of weak stiffness. Aiming at this problem, a whole-path posture optimization method of robotic grinding based on multi-performance evaluation indices is proposed in this paper. Firstly, a kinematic performance evaluation index is utilized to directly refine the regions of the robot workspace. Secondly, a stiffness performance evaluation index comprehensively considering the characteristics of grinding process is put forward. Simultaneously, a space conversion method is proposed to convert the stiffness index from the robot end to the tool end, and then a task-oriented flexibility ellipsoid on the tool-workpiece contact point is established. Furtherly, on these bases, aiming for the motion smoothness and the overall maximum stiffness of the robot in the whole grinding path, and taking the performance of the robot body as the constraint synergistically, an optimization model is established to optimize the posture of the robot. Finally, three groups of comparative grinding experiments are carried out on a KUKA kr210–2 robotic grinding platform. The results demonstrate that by using the posture optimization algorithm proposed in this paper, a better comprehensive performance including stiffness and motion smoothness in the whole grinding path can be achieved, and the workpiece after grinding has a higher removal depth and a better consistency, whose roughness has also been enhanced. These phenomenons indicate that the proposed method can significantly improve the accuracy and stability of grinding, thereby the effectiveness of this method is verified.

中文翻译：

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基于多性能评价指标的机器人磨削全路径姿态优化方法


工业机器人具有良好的机动性、高灵活性和低成本的优势，是执行机械加工操作的有前途且有竞争力的替代方案。然而，工业机器人在磨削等高精度加工领域的应用受到刚度弱的特点的极大限制。针对该问题，提出一种基于多性能评价指标的机器人磨削全路径姿态优化方法。首先，利用运动学性能评价指标来直接细化机器人工作空间的区域。其次，综合考虑磨削工艺特点，提出了刚度性能评价指标。同时，提出了一种空间转换方法，将机器人端的刚度指标转换到工具端，然后建立工具-工件接触点上面向任务的柔性椭球。进一步，在此基础上，以机器人在整个磨削路径中的运动平稳性和整体最大刚度为目标，协同以机器人本体的性能为约束，建立优化模型来优化机器人的姿态。 。最后在KUKA kr210-2机器人磨削平台上进行了三组对比磨削实验。结果表明，采用本文提出的位姿优化算法，可以在整个磨削路径中获得更好的刚度和运动平滑度等综合性能，磨削后的工件具有更高的去除深度和更好的一致性，其粗糙度也得到了增强。 这些现象表明，该方法可以显着提高磨削精度和稳定性，从而验证了该方法的有效性。