Automated Visual Guidance and Direct Metrology for Precision Manufacturing

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The objective of this research project is to determine if the pose of a three-dimensional object can be completely defined by the lateral-fringe distribution of white light interferometry in just one image, and if white light interferometry can be applied to simultaneously measure multi-axis motions of multiple micro objects. The approach is to firstly establish the mathematical relationship between the resulting lateral-fringe distribution and the six-degree-of-freedom motion of the targeted object, based on which an observer and the associated observability of the object's pose will be derived. Experiments will be conducted to verify the derived observability and to examine the achievable motion resolution in relation to structural vibration and image quantization. Secondly, real-time computation for lateral-fringe pattern analysis will be optimized and the associated temporal resolution of the proposed observer will be experimentally verified. Specifically, the achievable temporal resolution in relation to image size, object's geometry, and number of objects will be established. After motion resolution and temporal resolution are verified, this approach will be applied to measure six-degree-of-freedom motions of multiple micro objects within the field of view of a white light interferometer system.If successful, this research will lead to novel sensor technology that is capable of simultaneously measuring six-degree-of-freedom motions of multiple micro objects, including engineered devices, biological structures, measurement probes or manipulators, with nanometer resolution. It will also enable automated visual guidance for achieving automatic positioning, alignment, dynamic tracking, and controlled manipulation of multi-scale micro devices. When integrated with innovative design and implementation of tooling, the proposed measurement technique can be applied to various precision manufacturing processes. It can achieve direct metrology, placed to measure the motion which matters most to the application, and direct visual servo control, eliminating the effects of calibration error, nonlinearity, thermal drift of structure, and sensor drift. It will have potential applications in a wide spectrum of precision engineering problems, and a major impact on control of advanced instrumentation and automation of modern fabrication processes for precision manufacturing. Furthermore, the interdisciplinary nature of the project will broaden the education and training of graduate and undergraduate students. It is expected that the results of the project will enrich broader curriculum development efforts, particularly in the areas of sensor design, optical metrology, visual servo control, and micro/nano technology.