MODELING AND ESTIMATION FOR STEPPED AUTOMATIC TRANSMISSION WITH CLUTCH-TO- CLUTCH SHIFT TECHNOLOGY DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Sarawoot Watechagit, M.S. ***** The Ohio State University 2004 Dissertation Committee: Approved by Professor Krishnaswamy Srinivasan, Advisor Professor Chia-Hsiang Menq ______________________________ Professor Gregory Washington Advisor Department of Mechanical Engineering Copyright by Sarawoot Watechagit 2004 ABSTRACT A major problem in designing controllers for automatic transmissions in automobiles is that many of the relevant variables characterizing the performance of the power train are not measurable because of sensor cost and reliability considerations. This dissertation presents the development of model-based estimation for a stepped automatic transmission with clutch-to-clutch shift technology, to provide real-time information about some necessary but un-measurable variables. Specifically, model-based real-time estimation of clutch pressures for the clutches involved in the gear shifting process is developed and validated. In this dissertation, mathematical models for all systems affecting the dynamic behavior of the transmission, namely, the torque converter, transmission mechanical components, shift hydraulic system, and vehicle and driveline are developed. The main focus, however, is on the development of mathematical models describing the dynamic behavior of the transmission mechanical components, viz, the dynamics of the gear sets inside the transmission and the shift hydraulic system. This dissertation presents the development of a nonlinear dynamic model for the shift hydraulic system for the transmission of interest. The result of the model development presented here includes a fully detailed model, which is complex and highly nonlinear, as well as a simplified ii model which is used for real-time implementation. Resulting models are validated against experimental data. The availability of the shift hydraulic model leads to the development of the model-based clutch pressure observer. Sliding mode observers are used due to their ability to deal with nonlinear systems, robustness against uncertainties, and ease of implementation. In this dissertation, both continuous-time and discrete-time sliding mode observers are developed and implemented. Since the turbine torque is needed by the observer but is not available, an adaptive sliding mode observer is also implemented in this research to improve the on-line estimation of the turbine torque, and hence improve the accuracy of the clutch pressure estimation. The resulting observers are validated via off-line simulation tests, and are also implemented in real-time at different sampling frequencies on a test vehicle, in order to demonstrate observer performance and establish the feasibility of using the designed observers on current transmission control units. iii Dedicated to my mother iv ACKNOWLEDGMENTS I would like to thank firstly my advisor, Professor Krishnaswamy Srinivasan. No words can describe my appreciation for his invaluable guidance, support, encouragement, challenge, technical assistance, as well as his patience in correcting my language and scientific errors. I cannot thank him enough for introducing me to the field of System Dynamics and Automatic Control, as well as motivating me for doing research in the field of Automotive Engineering. Having him as an advisor and a role model made my stay at the Ohio State University a very rich academic experience. I thank also my committee members, Professor Chia-Hsiang Menq and Prof. Gregory Washington, for their time, as well as their helpful comments and suggestions. I want to express my thanks to Professor Vadim Utkin who introduced me to the field of Sliding Mode Control. His expert advice and comments have been very valuable and have helped me through out this research. I want to extend my thanks to Delphi Automotive Systems for their financial support. I want to thank Delphi Automotive System - Technical Center, Brighton, particularly for their hospitality during the period of my experimentation using the test vehicle. Especially, I would like to thank Dr. Quan Zheng for her technical suggestions, comments, and friendly support. I thank also Marty Temple for his help with my experimentation, as well as his expert advice on real-time implementation. My thanks v also go to Kyoung-Pil Hwang for his diverse technical comments. I also want to thank Dave Dues, Transmission Controls Staff Engineer, and Andrew Herman, Transmission Control Project Team Leader, for approving this project, and giving me a unique opportunity to work on a research project with such a real impact. I want to thank my friends, Pisit (New), Smart, Dr. Ratanatriwong, Dr. Wongsa- ngasri, Dr. Sitathanee, and many others for always being there for me. They have made my life in US very pleasant. I also wish to thank my friends in Ann Arbor, Michigan, for their hospitality, help, and support during the time I was running the experimentation at Delphi, especially, Prussara and Jian who let me use her house as my own house. To my mother, Amornrat, my deepest thanks for her unlimited love, sacrifice, support, and understanding during all these years of my education. I would not be who I am without her. My sincere thanks also go to my sister and brother-in-law, Sindrea and Sacha, for their continuous and unconditional support. And last, but not least, I want to thank my wife, Parasuang, with all my heart. She has been always on my side no matter what the problem is. I really thank her for her understanding and patience in letting me spend as much time as I needed to finish my education. I also want to thank the financial support during my early years in the graduate program from the Royal Thai Government, and the Department of Mechanical Engineering, Mahidol University. vi VITA September 27, 1971……………………….. Born – Samutsongkhram, Thailand 1990 – 1994 ……………………………...... B. S., Mechanical Engineering Kasetsart University, Thailand 1994 – 1996 ………………………………. Automotive-Technical Engineer Tripetch Isuzu Sales Co, Ltd., (Thailand) 1996 – 1999 ………………………………. M. S., Mechanical Engineering The Ohio State University 1999 – present ………………....................... Graduate Research Associate The Ohio State University PUBLICATIONS Watechagit, S., and Srinivasan, K., “Modeling and Simulation of a Shift Hydraulic System for a Stepped Automatic Transmission,” SAE Technical Paper, No. 2003-01- 0314, 2003 Watechagit, S., and Srinivasan, K., “Online estimation of operating variables for stepped automatic transmissions,” Proceedings of IEEE Conference on Control Applications, Vol. 1, pp. 279-284, June 2003 FIELD OF STUDY Major Field: Mechanical Engineering System Dynamics, Measurement and Controls; Modeling and Control of Smart Materials, Automotive System, Hydraulic Systems, and Automatic transmission vii TABLE OF CONTENTS Page Abstract ………………………………………………………………………………….. ii Dedication ………………………………………………………………………………. iv Acknowledgments ………………………………………………………………………. v Vita …………………………………………………………………………………..... vii List of Tables …………………………………………………………………………... xi List of Figures ………………………………………………………………………….. xii Nomenclature ………………………………………………………………………… xviii Chapters: 1. Introduction..................................................................................................................... 1 1.1 Background and Motivation ................................................................................... 1 1.2 Objectives of the Research...................................................................................... 4 1.3 Organization of the Dissertation ............................................................................. 7 2. Literature review............................................................................................................. 9 2.1 Transmission Model Development......................................................................... 9 2.1.1 Torque Converter......................................................................................... 11 2.1.2 Transmission Mechanical Subsystem.......................................................... 13 2.1.3 Driveline and Vehicle Dynamics................................................................. 16 2.1.4 Shift Hydraulic Subsystem .......................................................................... 17 2.2 Online Estimation for Automatic Transmissions.................................................. 19 2.3 Clutch-to-Clutch Controller Development ........................................................... 21 2.4 Conclusion ............................................................................................................ 25 viii 3. Transmission model development ................................................................................ 27 3.1 System Components.............................................................................................. 28 3.2 Torque Converter Model....................................................................................... 29 3.3 4-Speed Transmission Mechanical Subsystem Model ......................................... 30 3.3.1 Planetary Gear Train Model......................................................................... 31 3.3.2 Models of Transmission Shift Dynamics..................................................... 35 3.3.3 Clutch Torque Calculation