一种并联机床运动平台位姿测量方法

提出一种采用附加测量机构直接测量并联机床运动平台位姿精度的方法。其基本思想是根据运动平台的运动特性在固定平台和运动平台之间增设附加测量机构，当运动平台运动时带动测量机构运动，通过安装在测量机构上的传感器测得广义坐标参量， 经运动学建模即可得到运动平台的位姿。当测量机构位姿正解求解速度满足实时控制要求时，利用该反馈信息对机床进行实时精度补偿和控制。基于上述思想建立的并联机床位姿测量系统可部分排除机床切削力变形和运动副间隙等误差， 从而提高机床的位姿测量精度。以一种五坐标并联机床为例，介绍采用附加测量机构直接测量运动平台位姿精度的建模方法。其中， 测量机构的综合十分重要。测量机构的组成决定了运动学模型的复杂程度， 即决定了运动学模型的计算效率。

In order to directly measure the position and orientation of the platform of parallel machine tool, a new method based on additional measuring mechanisms is proposed. The mechanism is designed and installed between movable and fixed platforms according to the characteristics of the movable one. And the position and orientation can be obtained by modeling the kinematics in generalized coordination while the resolution speed of the model meets the need of real time control, it will be further used for compensating the errors of the machine tool.This measuring system can partly eliminate the deformation errors caused by cutting force and the errors caused by clearance between two relatively moved parts, and raise the precision of the machine tool. Taking the five-axis parallel machine tool as an example, the kinematics model of such a measuring mechanism is derived. Moreover, the synthesis of the measuring mechanism, which determines the model complexity and the calculation efficiency, is also studied.

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