自驱动关节臂坐标测量机精度保障技术研究

The technology of articulated arm coordinate measuring machine has been mature and applied in certain measuring fields after more than 30 years development. Some problems such as bad reliability and reproducibility existing in the measurement results have become the major issue for urgent solution, which are caused by the different measuring force, speed and acceleration during manual measurement and can not meet the need of national intelligent manufacturing and online automatic measurement. The self-driven articulated arm coordinate measuring machine is used as the research object in this project. Its new structure is designed based on the obtained quasi-static research results of the articulated arm coordinate measuring machine. In order to improve the dynamic measurement precision and to realize automatic measurement, the research self-driven articulated arm coordinate measuring machine will be regarded as a measuring system with rigid-flexible coupling and nonlinearity characteristic. Its dynamic characteristic and dynamic error research will be done. Collaborative optimization mechanism between the control model and structure design of self-driven articulated arm coordinate measuring machine will be researched based on the synthesize motion analysis and dynamic analysis. The full measuring error compensation model and the composite control model of self-driven articulated arm coordinate measuring machine will be built. The measuring error distribution model of the spatial measurement point will be further analyzed and established. The determining method of the optimal measurement position and attitude for the measured object will be determined based on the established measuring error spatial distribution model. And the measurement trajectory planning method will be researched, by which the high-precision and stable measurement of low precision measuring machine will be realized. The above research results will provide the theoretical and technical support for developing the self-driven articulated arm coordinate measuring machine, which is suitable for on-line measurement of intelligent manufacturing and for improving its measuring precision.

关节臂坐标测量机经过30多年发展，技术已成熟，形成一定的应用领域，但其手动测量及带来的不同测量力、速度和加速度，引起测量结果存在可靠性和复现性差等问题，不能满足国家智能制造和在线自动检测的需要，急需突破。本项目拟以自驱动关节臂坐标测量机为研究对象，在已取得的关节臂坐标测量机准静态研究成果基础上，设计其新型结构。以提高自驱动关节臂坐标测量机动态测量精度和实现自动测量为目标，针对具有刚柔耦合、非线性特性的测量机，以其动力学特性和动态误差研究为切入点，探索综合运动分析和动力学分析的测量机结构设计和控制模型协同优化机制。建立全误差补偿模型和复合控制模型，进一步分析和建立空间测量点误差分布规律模型，提出面向被测对象的最优测量位姿实用化确定方法，及在此基础上研究测量轨迹规划方法，实现低精度测量机高精度稳定测量。为研制适用于智能制造在线测量的自驱动关节臂坐标测量机和提高测量机测量精度提供理论和技术支撑。

关节臂坐标测量机广泛应用于汽车、航空、机械制造等领域，面对人工智能、智能制造的飞速发展，以及拖拽式关节臂坐标测量机存在的问题，本课题研究自驱动关节臂坐标测量机及精度保障技术，使关节臂坐标测量机可在线自动测量。本项目取得的成果包括：. 研究了自驱动关节臂坐标测量机机械结构，利用结构静力学分析和模态分析完成了关键部件的结构优化设计，解决了测量机因结构柔性变形引起的测头端定位偏差等问题，为测量机的自驱动控制和高精度定位测量提供理论基础。. 建立了自驱动关节臂坐标测量机测量模型，研究了自驱动关节臂测量机的静态、动态误差来源及其特性，针对角度误差、臂杆变形静态误差分别建立误差模型并加以修正，研究结构参数误差标定技术；探明了自驱动关节臂坐标测量机各项误差源对其定位与测量误差传递规律，建立了动态综合误差补偿模型，有助于提高自驱动关节臂坐标测量机的测量与定位精度。. 研究了自驱动关节臂坐标测量机同步控制策略、不同运动参数下的动态特性，针对测量机变速靠近和匀速触测方案，分别实现了S型曲线轨迹规划和直线插补轨迹规划。对自驱动关节臂坐标测量机最佳测量位姿的确定方法进行了研究，确定了最佳测量姿态规律，结合轨迹规划，为制定最优测量策略提供理论基础，实现低精度测量机高精度测量。. 在理论研究支持下，完成了自驱动关节臂坐标测量机样机研发，并配备了测控系统和专用测量及控制软件，实现了对测量机的运动控制和自动测量等功能，取得了一套较为完善的相关基础理论和研发经验。测量机对标准球和量块进行自动测量，小尺寸球的测量精度为0.008mm，较大尺寸部件的测量精度为0.126mm，重复性误差分别为0.038mm和0.192mm（k=2）。研究取得的成果和经验将为后续的自驱动关节臂坐标测量机的研究提供理论和技术支撑。