PhD, University of Cincinnati, 2018, Engineering and Applied Science: Mechanical Engineering
System health assessment, as one of the most critical tasks in industrial data analytics, focuses on determining the current health condition and detecting the incipient fault. Recently, it has been challenging that the conventional strategy, which relies on a static health reference model along with a fixed threshold, is asked to fulfill the assessment requirements in the nonstationary monitoring environment. The dynamic data contexts might bring incorrect health estimation to the system. This dissertation presents an enhanced systematic online health assessment approach with adaptive self-learning techniques. The method enables the identification of novel working condition states, such as new rotating speed or processing recipe, and the recognition of new degradation extent in the arriving monitoring data, and includes them into the prior learning models. Hence, such continuously growing model could achieve the assessment more efficiently and accurately.
This research work proposes the methodology of the enhanced health assessment approach, along with detailed technologies utilized in each implementation step, including a self-learning technique, a change detection and recognition strategy, and a clustering algorithm. Through a toy case on a rotor test bed, the dissertation intuitively described the detailed assessment process and demonstrated that the proposed approach, compared with the static model solution, could successfully capture the newly encountered patterns in the testing data.
The feasibility of the proposed approach was demonstrated by two industrial use cases. For the semiconductor manufacturing process monitoring case, the proposed approach was able to correctly estimate the health states of the data measured from different experiments while being trained by one experiment observations. Additionally, it surpassed two existed assessment methods with higher overall assessment accuracy. For the power electronics modules monitoring case, the (open full item for complete abstract)
Committee: Jay Lee Ph.D. (Committee Chair); Thomas Richard Huston Ph.D. (Committee Member); Jay Kim Ph.D. (Committee Member); Manish Kumar Ph.D. (Committee Member)
Subjects: Mechanical Engineering