ENBIS-8 in Athens

21 – 25 September 2008 Abstract submission: 14 March – 11 August 2008

An Overview of Stream of Variation Theory and Applications

22 September 2008, 14:20 – 14:40


Submitted by
Jianjun Shi
Jianjun Shi The Carolyn J. Stewart Chair Professor
Georgia Institute of Technology
This presentation will provide an overview of research and applications in the theories of Stream of Variation, which is a model-based methodology for monitoring, diagnosis, and control of multistage manufacturing processes (MMP). A MMP involves multiple workstations or operations to produce products. The variations may occur at any operations, which further propagate to the down stream operations. The final product quality is a stack-up, or accumulation of all process variations. Variation modeling, analysis and control for MMP is a very challenging problem due to the complexity in its configuration, variation sources, and interactions among multiple components. In the SoV theory, a state space modeling approach is developed to describe the variation propagation and links the product quality with the process faults in a MMP. This model integrates the product design (CAD) information and the process planning (CAPP) information such as the fixture layout and workpiece setup at each stage. Based on this model, a system level process design, monitoring, sensor-distribution, root cause identification, and active dynamic control are pursued by integrating system and control theory, advanced statistics with engineering knowledge. Besides the SoV research, its applications in industrial processes will also be presented.
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