On the basis of the characteristics of optical systems in a space camera, a focusing mechanism suitable for the camera was designed optimally. Firstly, to meet the overall design requirements of the camera for the lower mass and smaller size, a double-slider mechanism combined a screw and a link was chosen to transform the screw's running into the line movement of the focusing mirror along the optical axis direction and to overcome the defocusing of the system by adjusting the image movement. Then, the focusing accuracy of the focusing mechanism was analyzed and the error source and error calculation were discussed. Finally, the vibration and accuracy tests were performed on the mechanism. It shows that the optimized focusing mechanism has a weight of only 2. 5 kg and a shape size of 186 mm×144 mm×60 mm. Furthermore, the vibration and accuracy tests indicate that the focusing mechanism can offer the first frequency of 505 Hz, positioning accuracy of 0. 008 mm, and the repeatability positioning accuracy of 0. 002 5 mm, respectively. These results satisfy the requirement of the optical system very well and show that the mechanism is characterized by the compact struc-ture, high stiffness and good accuracy.%根据轻型空间相机光学系统的特点以及相机的焦深,优化设计了一种适用于该类相机的调焦机构.为了满足相机总体要求,综合考虑重量、外型尺寸、刚度、误差等各方面的因素,选择丝杠和连杆配合使用的双滑块机构,将丝杠的转动通过连杆机构转换成调焦镜沿光轴方向的直线运动,实现了通过调整像面移动来解决离焦的问题.对该调焦机构在调焦范围内的调焦精度进行了分析,介绍了该调焦机构的误差来源和计算方法.最后,对该调焦机构进行了振动试验和精度试验.优化设计后的调焦机构总重量为2.5 kg,外型尺寸为186 mm×144mm×60 mm.振动试验和精度试验的结果表明,该调焦机构的基频为505 Hz,单向定位精度为0.008 mm,重复定位精度为0.002 5 mm,满足相机总体提出的刚度和精度要求.该调焦机构具有刚度高、结构紧凑、定位精度高等特点,能够满足空间调焦的设计要求.
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