400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 Web: www.sae.orgSAE TECHNICAL PAPER SERIES 2004-01-1227 Development of a Slip Control System for a Lock-Up Clutch Akira Higashimata, Kazutaka Adachi, Satoshi Segawa and Nobuo Kurogo Nissan Motor Co., Ltd. Hironobu Waki Jatco Co., Ltd. Reprinted From: Transmissi on & Driveline Symposium 2004 (SP-1817) 2004 SAE World Congress Detroit, Michigan March 8-11, 2004Downloaded from SAE International by Univ of California Berkeley, Sunday, August 05, 2018All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise,without the prior written permission of SAE. For permission and licensing requests contact: SAE Permissions 400 Commonwealth DriveWarrendale, PA 15096-0001-USAEmail: [email protected]: 724-772-4891Tel: 724-772-4028 For multiple print copies contact: SAE Customer ServiceTel: 877-606-7323 (inside USA and Canada)Tel: 724-776-4970 (outside USA)Fax: 724-776-1615Email: [email protected] ISBN 0-7680-1319-4Copyright © 2004 SAE International Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. A process is available by which discussionswill be printed with the paper if it is published in SAE Transactions. Persons wishing to submit papers to be considered fo r presentation or publication by SAE should send the manuscript or a 300 word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE.Printed in USADownloaded from SAE International by Univ of California Berkeley, Sunday, August 05, 20182004-01-1227 Development of a Slip Control System for a Lock-Up Clutch Akira Higashimata, Kazutaka Adachi, Satoshi Segawa and Nobuo Kurogo Nissan Motor Co., Ltd. Hironobu Waki Jatco Co., Ltd. Copyright © 2004 SAE International ABSTRACT Lock-up operation of an automatic transmission is known as one good method of improving fuel economy. However, locking up the transmission at low vehicle speeds can often cause undesirable vibration or booming noise. Slip control of the lock-up clutch can resolve these problems, but the speed difference of the lock-up clutch needs to be cont rolled at a certain value. This control system has to overcome large changes in the parameters of the lock-up system at low vehicle speeds and also changes with regard to the speed ratio in a continuously variable transmission (CVT). In this study, this complex non-linear system has been modeled as a first-order linear parameter varying (LPV) system. A robust control algorithm was applied taking various disturbances into account to design a new slip lock-up control system. First, the feedback controller was designed using µ synthesis to attain robust stability and the desired performance for all the operating conditions considered, and t hen a feedforward controller was added to obtain better response. As a result, a two-degree-of-freedom control system was implemented, which enables slip control to start at a very low vehicle speed and the transmission is completely locked up before reaching a vehicle speed of 20 km/h. In this paper, the results of simulations and driving tests are presented to demonstrate the effectiveness of this slip control system. INTRODUCTION The use of automatic transmissions in vehicles is increasing worldwide every year for the purposes of reducing the driver’s workl oad and improving driveability. An automatic transmission has a torque converter that plays a key role in preventing engine stall when the vehicle stops, controlling jolting vibration, and assisting start-off through the effect of torque multiplication. On the other hand, the torque converter causes a loss of engine torque. The nearer the speed ratio of the input (impeller) rotati