空间相机均力输出式调焦机构

Focusing mechanism with equal output forces for space camera

为了补偿空间相机因所处复杂运载环境和空间运行环境导致的焦平面偏移,研制了一套利用均力输出组件驱动,正反双曲柄滑块机构传动,直动组件导向的新型高精度调焦机构。介绍了其结构组成和运动原理,并对其误差来源及影响因素进行了深入分析。该调焦机构采用两点支撑方式,两支撑点均力输出且无同步性误差,机构内应力小,运行平稳,调焦精度高;运动副采用预压消间隙措施,有效消除配合间隙,无空回,重复精度高。在模拟空间环境条件下,对其各项参数进行了测试。试验结果表明,该调焦机构可在±1.77mm间调焦,直线定位精度大于±8μm,重复性优于±2μm;同步性误差小于±4μm,重复性优于±3μm;调焦行程范围内调焦反射镜转角精度优于±5″,重复性优于±1.5″。得到的结果能够满足空间相机在复杂空间环境下的成像需求。

To compensate the offset from optimal focal plane position of a space camera due to its complicated launch environment and space operating environment,a new high-precision focusing mechanism was proposed.The mechanism is driven by equal output components,transmitted by apositive and negative slider-crank mechanisms and its guiding is completed by a direct-acting component.The structural composition and motion mechanism were introduced and its error sources and influence factors were analyzed.The focusing mechanism was supported by the direct-acting component with two points and the output force of each point was equivalence,so that it has no synchronization motion error,and characterized by low internal stress in the organization and high swing angle precision.Furthermore,the gap relieving by preload was used in all kinematics pairs to eliminate the error of back lash in the focusing mechanism to improve focusing accuracy.The test parameter was tested in a sim-ulated space environment,and the analysis and experiment results show that the focusing range of the focusing mechanism is±1.7 7mm,the linear position precision and repeatability are better than±8μm and ±2μm respectively,the synchronization motion error is less than ±4μm,and the repeatability better than±1″.In focusing travel ranges,the tilt angle accuracy of the focusing mirror and its repeatability are better than± 5″and±1.5″,respectively.These results meet the needs of complex spatial imaging environments.