Title: Slope shift strategy for automatic transmission vehicles based on road slope and vehicle mass identification

Authors: Guang Xia; Ruiqi Yan; Xiwen Tang; Baoqun Sun

Addresses: Institute of Automotive Engineering, Hefei University of Technology, Hefei, Anhui 230009, China ' Institute of Automotive Engineering, Hefei University of Technology, Hefei, Anhui 230009, China ' School of Electronic Confrontation, National University of Defense Technology, Hefei, Anhui 230037, China ' Institute of Automotive Engineering, Hefei University of Technology, Hefei, Anhui 230009, China

Abstract: Road gradient and vehicle mass are estimated using a method with variable forgetting factor, which has strong adaptability and following capability. A control strategy with hierarchical correction is proposed for a vehicle that shifts on a slope. The shifting process is composed of the upper identification decision and lower shift correction executive layers. The upper layer focuses on collecting vehicle parameters, estimating road gradient and vehicle mass, and presenting a modified control decision. The lower layer performs the slope shift schedule from the upper layer. Results of the simulation test are shown. Furthermore, the designed strategy can duly downshift the gear uphill and avoid frequent shifting, thereby reducing the wear of the transmission parts and downshifting the gear timely downhill to utilise the torque characteristics of engine braking and reduce the wear of the braking system.

Keywords: double-clutch automatic transmission; forgetfulness factor; slope estimation; mass estimation; shift modification; hierarchical control; least square method.

DOI: 10.1504/IJVD.2019.111585

International Journal of Vehicle Design, 2019 Vol.81 No.3/4, pp.191 - 211

Accepted: 18 May 2020
Published online: 02 Dec 2020 *

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