Design, Modeling and Control of Novel Transmission Systems


Student: Azrin Zulkefli

In North America, the automatic transmission dominates the automotive market. This transmission uses planetary gearsets and wet clutches to change the speed/torque ratio between the engine and the vehicle.  Clutch to clutch shift is a critical technology for automatic transmissions. The basic concept is to synchronize the engagement of the on-coming clutch and the disengagement of the off-going clutch to realize the gear shift. The shift synchronization requires that once the off-going clutch starts releasing, the on-coming clutch should immediately transfer torque to maintain a desirable output torque. To have a smooth synchronization and shift, it is crucial to place the on-coming clutch piston at a pre-determined position where the clutch piston just makes contact with the clutch packs before the shift, and this again highly depends on a precise and robust clutch control.

Figure 1. Transmission Test Fixture.

So far the clutch is primarily controlled in an open-loop fashion due to the lack of position or pressure sensors (the engine and vehicle speed signals can be used for feedback, but typically are too late to compensate for the clutch motion). So our focus has been on developing models and systematic feedback controls for the transmission clutch systems (see Figure 1). Specifically, we have developed dynamic models for the ball capsule system and analyzed its stability. We also designed a new clutch fill control method using customized dynamic programming. We further developed a nonlinear controller for the clutch system with pressure feedback. Currently we are working with our industry collaborator to incorporate a miniature MEMS based pressure sensor in the clutch system and implement the above control methods in a production vehicle. We have also worked on the driveline control for an automated manual transmission system.



    1. Sun, Z. and Hebbale, K., “Challenges and Opportunities in Automotive Transmission Control”, Proceedings of the 2005 American Control Conference, Portland, OR, pp.3284-3289, June, 2005.

    2. Song, X., Zulkefli, A., Sun, Z. and Miao, H., “Modeling, Analysis, and Optimal Design of the Automotive Transmission Ball Capsule System”, ASME Transactions on Journal of Dynamic Systems, Measurement and Control, Vol. 132, 021003, March, 2010.
    3. Song, X., MohdZulkefli, A., Sun, Z. and Miao, H., “Automotive Transmission Clutch Fill Control Using a Customized Dynamic Programming Method”, ASME Transactions on Journal of Dynamic Systems, Measurement and Control, Vol. 133, 054503, 2011.
    4. Song, X. and Sun, Z., “Pressure Based Clutch Control for Automotive Transmissions Using a Sliding Mode Controller”, in press, IEEE Transactions on Mechatronics, 2011.
    5. Song, X., Sun, Z., Yang, X. and Zhu, G., “Modeling, Control, and Hardware-in-the-Loop Simulation of an Automated Manual Transmission”, Proceedings of the IMechE, Part D, Journal of Automobile Engineering, Vol. 224, No. 2, pp.143-160, 2010.