Study On AMT Fault Diagnosis And Tolerant Control Of A Hybrid Electrical Vehicle

Automated Manual Transmission (AMT) is based on Manual Transmission (MT), which changes the manual shift mechanism to automated shift mechanism. Due to the advantages of little changes of production line and inheriting the high efficiency characteristic of manual transmission in the same time, it’s widely used in small cars, commercial vehicles and trucks. Because AMT’s operating performance and operational stability has important influence on vehicle driving safety, so many domestic and foreign scholars draw their attention to the AMT’s fault diagnoses research.This thesis first briefly introduces the hybrid cars with AMT, then introduce the development of fault diagnosis and recent research production of domestic and international scholar. In order to fully study the AMT feature when fault occurs, and how the fault influence hybrid system. Using Functional Analysis (Functional Analysis) and failure mode and effects Analysis (FMEA) find possible failure of all parts of AMT and what causes them as well as the harms of these faults on the system. Then getting its critical failure according the risk priority number (RPN), which include motor failure, push and pull cable failure, shifting fork failure/synchronizer and MT gear/bearing failure. After studying the fault simulation methods of the critical failure and those parts’ dynamics analysis, building the AMT mathematic model of failure diagnosis. Using the model above to simulate the reflection of the displacement sensor, the current sensor and the output shaft speed sensor when those critical failure occurs. Thus the influence of the fault on the system can be obtained. For the faults of AMT sensors, Using the signal redundancy to find out the relationships of those sensors. After that, establishing AMT sensor fault diagnosis model, and using it to Study vehicle’s performance as well as the treatment when these failure occurs.The studies using the failure mode and effects analysis (FMEA) to find out critical failure and analyze their influence on HEV AMT system. Using the signal redundancy to analyze sensors’fault. Above research of AMT failure analysis can improve the HEV installed AMT’s safety in the process of design and vehicle operation.