双驱动六点支承平台设计及调平算法

Algorithm and design of leveling stages with six point supports and two inputs

针对传统三点支承平台的欠约束和欠驱动问题,基于运动学原理提出了一种双驱动六点支承平台。该平台在自然状态下具有确定位姿,在输入状态下具有确定运动,由此解决了三点支承平台的欠约束和欠驱动问题。以加速度计作为测量传感元件,提出了一种基于重力加速度方向矢量的两输入调平算法,并利用平台法线矢量运动变换获得了平台的转动角度。该平台调平范围±5°,水平重复精度优于0.001 7°,具有运动确定以及稳定性高的特点,可用于精密仪器及机械的自动调平。最后,指出了调平的二转动自由度姿态控制的运动学本质。

Aiming at the under-constraint and under-actuator for leveling stages with three point supports, a stage with six point supports using two inputs only is proposed. The stage possesses definite position and orientation in natural states and definite motion in input states. A leveling algorithm of the acceleration of gravity via two inputs is presented. The rotational angle of the platform is acquired via motion transformation of normal vector by measuring the acceleration of gravity. The experiment result shows that the repeatability of leveling is superior to 0. 001 7 degree in two directions. The orientation and motion of the mechanism are deterministic and with high stability. The stage can be used for precision machines and instruments. Finally, the kinematic nature of two degrees of freedom orientation control for leveling is pointed out.