Industrial robots are traditionally used at machining cells for machine feeding and workpiece handling. A reassignment of tasks to improve the productivity requires a modelling of the robot behaviour from the point of view of its position precision. This paper characterizes and predicts the precision achievable when drilling with an industrial robot in order to use it in machining operations.

Robot behaviour and drilling phenomena are analysed to determine working accuracy and their contribution in position deviation and uncertainty. An efficient model for drilling is developed, applying quaternions and considering the influence of all cutting tool angles, providing a very precise estimation of drilling torques and forces. An innovative model for the robot is developed based on multibody systems, using mixed natural coordinates that enhance the computing and deliver outputs with direct interpretation. Besides, the effect of stiffness is added in joints as additional element.

The complete robot-process model shows the significative process influence in working precision against robot influence. This influence is responsible of up to 40% of the total uncertainty. The model and the tests performed show that the deviations and their uncertainties depend strongly on drilling forces and the robot configuration. In the other hand, the model allows to correct the systematic behaviour in robot deviations and improve with that the position tolerance of the holes to be drilled.

传统上，工业机器人通常在加工单元中用于机器进给和工件处理。为了提高生产率而重新分配任务需要从其位置精度的角度对机器人行为进行建模。本文描述并预测了使用工业机器人进行钻孔以将其用于加工操作时可达到的精度。

分析机器人的行为和钻孔现象，以确定工作精度及其对位置偏差和不确定性的影响。使用四元数并考虑所有切削刀具角度的影响，开发了一种有效的钻探模型，可以非常精确地估算钻探扭矩和力。该机器人的创新模型是基于多体系统开发的，使用混合自然坐标来增强计算能力并通过直接解释提供输出。此外，刚度的效果作为附加元素添加到了接头中。

完整的机器人过程模型显示了在工作精度方面对机器人影响的重要过程影响。这种影响最多占总不确定性的40％。进行的模型和测试表明，偏差及其不确定性在很大程度上取决于钻孔力和机器人的配置。另一方面，该模型可以校正机器人偏差中的系统行为，并通过提高待钻孔的位置公差来改善。