多轴数控机床的运动仿真及干涉检查研究

发布时间：2018-06-01 05:28

本文选题：多轴数控机床 + 虚拟装配　；参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：多轴数控机床结构复杂、形式多样、运动灵活,在加工过程中容易产生碰撞问题。多轴数控机床的碰撞问题难以依靠人工进行预防,是多轴数控加工中亟需解决的问题。基于计算机图形技术,本文提出了针对任意形式的多轴数控机床的离线干涉检查方法及实时防碰撞策略。本文介绍了以组件-模型结构为基础的虚拟数控机床构建方法,并结合数控机床刚体特性选择了STL等实体网格模型作为仿真模型,同时给出了程序设计方法。在此基础上对机床坐标系和工件坐标系下的运动进行了运动学模型分析,明确虚拟数控机床运动链上各个组件及模型位置的计算方法,并介绍了实现运动仿真的关键技术。干涉检查是本文研究的重点,在离线干涉检查部分注重研究准确高效的干涉检查的算法,在分析数控机床运动特性及各种干涉检查方法的基础上,最终选取以OBB为包围体的层次包围树方法对实体模型处理,并对此方法进行优化,提出更高效的局部更新层次包围树的算法,同时以模型间三角面片相交作为干涉的判断标准,保证干涉检查的精度与建模精度一致。而在实时防碰撞部分则注重干涉检查策略的研究,针对数控机床运行于自动模式时的特点,本文提出了采用两套缓存区的防碰撞策略,通过干涉检查的安全代码才能够驱动数控机床运动。针对手动模式下的特点,本文提出了在运动方向上进行后台预检测的策略,提前检测出行程范围内的潜在碰撞位置并做出反应。基于本文的算法及策略,作者开发了防碰撞系统并进行了离线干涉检查及实时防碰撞实验,实验结果验证了本文方法的正确性及可行性。
[Abstract]:Multi-axis NC machine has complex structure, various forms and flexible motion, so it is easy to collide in the process of machining. The collision problem of multi-axis NC machine tools is difficult to be prevented manually, which is an urgent problem to be solved in multi-axis NC machining. Based on the computer graphics technology, this paper presents an off-line interference inspection method and a real-time anti-collision strategy for arbitrary multi-axis NC machine tools. This paper introduces the construction method of virtual NC machine tool based on component-model structure, and selects STL and other entity mesh model as simulation model combined with the rigid body characteristics of NC machine tool, and gives the programming method at the same time. On this basis, the kinematics model of the machine tool coordinate system and the workpiece coordinate system is analyzed, the calculation method of each component and model position on the motion chain of the virtual NC machine tool is clarified, and the key technology to realize the motion simulation is introduced. Interference detection is the focus of this paper. In the part of off-line interference inspection, we focus on the research of accurate and efficient algorithms for interference detection. On the basis of analyzing the motion characteristics of NC machine tools and various methods of interference detection, Finally, the hierarchical bounding tree method with OBB as the bounding body is selected to deal with the solid model, and the method is optimized, and a more efficient algorithm for updating the hierarchical bounding tree is proposed. At the same time, the intersection of triangular patches between the models is taken as the criterion of interference. The accuracy of interference detection is consistent with that of modeling. In the real time anti-collision part, we focus on the research of interference inspection strategy. In view of the characteristics of NC machine tool running in automatic mode, this paper proposes two sets of anti-collision strategy of buffer area. The safety code of interference check can drive the movement of NC machine tool. In view of the characteristics of manual mode, this paper proposes a strategy of background pre-detection in the direction of motion, which can detect the potential collision position in the travel range in advance and respond to it. Based on the algorithm and strategy of this paper, the anti-collision system is developed and the off-line interference inspection and real-time anti-collision experiment are carried out. The experimental results verify the correctness and feasibility of this method.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG659

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