System Diagnosis and Fault Mitigation Strategies for an Automated Manual Transmission

The introduction of hybrid vehicle architectures into the mass car market has dramatically increased fault detection and mitigation strategies seen in vehicles to match the growth in potential failures coming from increasingly complex powertrain architectures. To meet this increased demand for fault detection and mitigation of multiple powertrain components, advanced methodologies have been developed to determine the functional safety of systems. This paper focuses on the use of one of those advanced methodologies, structural analysis, to develop the design, implementation, diagnostics, and control of a prototype automated manual transmission. Structural analysis is the concept of analyzing the mathematical structure of a system to determine the diagnostic coverage of sensors in the system. From this information, a controls strategy can be developed to address potential failure modes of a system utilizing the derived equations and knowledge of which sensors provide coverage for failure modes analyzed. Additionally, lack of coverage for failure modes can be seen through this analysis and the need for additional sensors determined to provide coverage in those areas. Using structural analysis, the Ohio State University EcoCAR 3 research team carried out a diagnostic and mitigation study during the development of their automated manual transmission.