基于实体模型的虚拟微装配视觉伺服研究

微装配的主要问题是装配的器件小,装配精度高,一般用显微镜作为视觉传感器对装配运动进行控制。在大放大倍数下,显微镜的视场和景深很小,这时操作对象和操作工具就不会同时处在焦平面内,使得图像模糊,操作很难完成。利用显微镜的聚焦理论,提取对象的三维信息,构造对象的实体模型,使微装配在虚拟环境中进行,而实际环境只起监视的作用,当对象和工具不动时,虚拟操作环境不变化,而当操作对象和工具位置变化时,重构三维环境,使得虚拟环境和实际环境具有严格的位置对应关系。试验和仿真结果表明,该方法可以克服物体在显微镜下的失焦问题,而且操作方便。

STUDY OF VISUAL SERVOING FOR VIRTUAL MICROASSEMBLY BASED ON SOLID MODEL

The major obstacles encountered in microassembly are that the to-be-assembled objects are very small in size and thus strict precision on assembly is required. Usually a microscope is used as a visual sensor to control the assembling movement. Under high magnitude of resolution and amplification, the viewing field and focal depth are too small and too short to allow the objects and tools become focused within the same focal plane at the same time, resulting in the blurred images, therefore the microscope fails to accomplishes the expected task. The focus theory of microscope is exploited fully to obtain the three dimension information of object and tool to constitute a solid model, the microassembly is carried out in virtual environment, object and tool in reality environments serve to check the correspondence between virtual microassembly and the changes in reality. When there are no changes in the objects and tool, virtual environment is kept stable, upon the changes in the objects and tool, virtual environment become reconstituted. Our results on experimentation and simulation show that virtual microassembly approach helps to avoid the defocus problem under the microscope and also to make the operation feasible and easier.