CAJ | 학술논문

为了得到单级6自由度悬浮工作台的运动学模型,将非接触驱动和支承等效为由万向联轴器、伸缩杆和平面运动副组成的支链,在移动台转角很小的情况下,平面运动与离面运动相互独立,且不受伸缩杆与基座表面垂直度误差的影响.基于欧拉转动定理,通过计算工作台在2个不同位置时光轴与反射镜镜面交点之间的距离,建立了工作台平面运动测量系统三维对准误差模型.测量误差的分布及其对误差源的灵敏度表明,二维对准误差分析方法忽略的离面对准误差的灵敏度最大可达平面对准误差灵敏度的25%,L形反射镜绕z轴偏转造成的对准误差及镜面垂直度误差是影响测量误差的主要因素.
위료득도단급6자유도현부공작태적운동학모형,장비접촉구동화지승등효위유만향련축기、신축간화평면운동부조성적지련,재이동태전각흔소적정황하,평면운동여리면운동상호독립,차불수신축간여기좌표면수직도오차적영향.기우구랍전동정리,통과계산공작태재2개불동위치시광축여반사경경면교점지간적거리,건립료공작태평면운동측량계통삼유대준오차모형.측량오차적분포급기대오차원적령민도표명,이유대준오차분석방법홀략적리면대준오차적령민도최대가체평면대준오차령민도적25%,L형반사경요z축편전조성적대준오차급경면수직도오차시영향측량오차적주요인소.
A kinematic model of a 6-DOF precision levitation stage is developed by equivalent chains consisting of universal joints,extensible legs and planar joints instead of non-contact actuators and bearings.The moving platform in-plane motion is independent of its out-of-plane motion while rotation displacements are small,and this kinematic characteristic does not change if extensible legs are not perpendicular with the base surface,so the accuracy of this stage mainly depends on the measurement system accuracy.Based on Euler's rotation theorem,a 3-D measurement alignment error model for in-plane motion of the precision levitation stage is derived by calculating the distance of two intersection points of the L-shape mirror and the laser beam,and the influence of alignment errors on measurement error is analyzed by calculating error distributions and their sensitivity to error sources.The results show that the sensitivity of out-of-plane alignment errors,and which is ignored in the previous 2-D analysis,may reach to 25%of the sensitivity of in-plane alignment error,and the most important error sources include L-shape mirror alignment error caused by rotation around z-axis and its orthogonal error.