Research On Balance System Of Portable Articulated Coordinate Measuring Machine

Portable Articulated Coordinate Measuring Machine(PACMM)is a kind of coordinate measuring apparatus with large measuring range and flexible and portable features.At present,in order to reduce the impact of PACMM self-weight on the comfort,its balance mechanism is usually external,complex structure,the existence of measuring dead ends,and affect the measurement flexibility and measurement accuracy.This paper mainly researches the PACMM balance system to improve PACMM measuring comfort without affecting its measuring accuracy.The main work includes:1.By analyzing the mechanical structure and measurement principle of PACMM,the influence factors of the accuracy of PACMM are analyzed.These factors are taken into account when designing the balance system to avoid the influence of PACMM measurement accuracy.The gravity model of joint coordinate measuring machine is established,which provides the theoretical basis for designing balance system.Using the arc spring build PACMM balance system is put forward.2.Overview spring parts’ synthesized property and infer the formula of the elastic characteristic of the arc spring.Then,the parameters of the elastic properties of the arc spring are obtained,and the specific effects of these parameters on the elastic properties are analyzed,so as to obtain the best parameters of the arc spring.3.Analyze the elastic moment that the arc spring generated to the first swing joint,and the gravity moment that parts after the first joint generated to the first swing joint.The matching degree between the elastic moment of the arc spring balance system and the gravity moment is verified by establishing the unbalanced moment model.The influence of parameters of the arc spring on the unbalanced moment is studied.And parameters are adjusted to achieve the optimal matching.4.The effect of the balance of the arc spring balance system is verified by experiments.Using laser displacement sensor to detect whether the arc spring will cause deformation of the PACMM base.By comparing the measurement accuracy of the PACMM before and after the assembly of the arc spring balance system,it is checked whether the arc spring balance system affects the measurement accuracy of the PACMM by affecting the accuracy of the first swing joint.