Integrating Gear Shifting Preference into Personalized Shift-Scheduling Calibration

Shift-scheduling calibration of automatic transmission (AT) vehicles is vital for both driving experience and automobile industry. Shifting schedules are usually calibrated with the consideration of fuel economy and drivability while neglecting the individual driving preference. In this work, we propose to exemplify the individual shifting preference by integrating the manual transmission (MT) shifting habit into the AT shift-scheduling calibration, where the habit is reflected as the shifting points and is available in most automated manual transmission (AMT) vehicles. The automated calibration of AT shifting schedules is directed by using the particle swarm optimization (PSO), during the virtual automobile cycle test, i.e., FTP-72. Candidate shifting-schedules are generated in the overlapped zone of MT shifting points and the space around the base map, and are evaluated on both shifting quality and fuel economy. Through iterations, the generated candidate shift schedules are tested and assessed until the overall performance reach the optimum. Experimental results are presented to show the effectiveness of the proposed method, which retains the shifting preferences as well as enhances the performance index by about 5%, 4%, and 2% for the drivers with aggressive, moderate, and mild styles, respectively.

Influence of the Sleeve Teeth Shape Parameters on the Shifting Process of Automated Manual Transmission for Electric Vehicles

Electric vehicles equipped with automated manual transmission (AMT) provide the potential for improving the power and economic performance. However, due to the direct connection between the driving motor and the input shaft of the transmission, the higher moment of inertia at the input of AMT would lead to a poor shift quality. Based on the dynamic analysis of the engagement process of AMT without synchronizer, the dynamic model of the engagement process was established by using AMESim software. Through the analysis of the engagement process, it was concluded that the higher contact force and longer meshing duration under reverse contacting engagement condition is the main reason for the shift difficulty. In order to improve the shift quality, the influences of the sleeve teeth shape parameters of reverse contacting chamfer on the engagement process were analyzed and the simulation validation was performed. The simulation results showed that reducing the width and increasing the angle of the reverse contacting chamfer can effectively reduce the engagement duration and the contact force impulse, although the vehicle jerk was increased slightly, which did not exceed the most stringent criterion value of 10 m·s-3. Optimization of teeth shape parameters of reverse contacting chamfer can be considered to improve the shift quality of the electric vehicle equipped with an AMT.

Integrated Prognostics Observer for Condition Monitoring of an Automated Manual Transmission Dry Clutch System

The closed loop feedback control system of an Automated Manual Transmission (AMT) electro-pneumatic clutch actuator is used for intelligent real time condition monitoring, enhanced diagnostics and prognostic health management of the dry clutch system, by integrating with the existing gearbox prognostics observer. The real-time sensor data of the clutch actuator piston position is analyzed for monitoring the condition of the clutch system. Original parameters of the new clutch are stored in the Electrically Erasable Programmable Read-only Memory (EEPROM) of the AMT controller and the real-time data is used by the observer for assessing the degradation/wear of the frictional clutch parts. Also, clutch slip during torque transmission is monitored, using the engine speed and the gearbox input shaft speed from Controller Area Network (CAN). Condition monitoring of clutch system provides enhanced prognostic functionality for AMT system which ensures consistent clutch performance, gear shift quality and timely warning for recalibration, repair and/or replacement of the critical wear and tear parts. Also, systematic analysis of the monitored data provides an accurate diagnosis of a developing fault. Thus, with the advanced control systems in place for AMT, a closed loop feedback based condition monitoring system is modelled for improved diagnostics and prognostics of AMT clutch system.