关节臂式坐标测量机热误差仿真建模及补偿

Modeling and Compensation of Thermal Error for Articulated Arm Coordinate Measuring Machine

关节臂式坐标测量机受工业现场环境温度的影响较大,对其进行热误差建模及补偿是提高测量精度和稳定性的重要方法。为探明关节臂式坐标测量机热变形规律及其对运动学参数的影响,建立了关节臂式坐标测量机的三维模型进行有限元分析,得到了热变形分布图。提出一种虚拟坐标测量方法。通过分析发现了温度变化对关节臂式坐标测量机的单点重复精度影响很小,但对空间距离测量精度影响非常显著。在有限元分析基础上,得到关节臂式坐标测量机各运动学参数的热变形规律,并建立了热误差补偿模型。通过对热误差模型进行仿真验证,距离误差从0.035 mm提高到了0.014 mm,极大提高了关节臂式坐标测量机的空间距离精度及稳定性。

The articulated arm coordinate measuring machine(AACMM)is affected by the ambient temperature of the industrial site.Thermal error modeling and compensation is an important method to improve the accuracy and stability of AACMM.To explore the thermal deformation law of the AACMM and its influence on the kinematic parameters,the finite element model of the AACMM is established,with which the finite element analysis is carried out and the thermal deformation distribution map is obtained.To obtain the kinematic parameters of the AACMM from the finite element model,a virtual coordinate measurement method is proposed.By analysis,it is found that the temperature change has little influence on the single point repetition accuracy of the AACMM,but has a significant impact on the spatial distance measurement accuracy.Based on the finite element analysis,the thermal deformation law of kinematic parameters of the AACMM is obtained and the thermal error compensation model is established.Through the simulation and verification of the thermal error model,the distance error is decreased from 0.035 mm to 0.014 mm,which greatly improves the measurement accuracy and stability of the articulated arm coordinate measuring machine.