Study on Oil Pressure Characteristics and Trajectory Tracking Control in Shift Process of Wet-Clutch for Electric Vehicles

Junqiu Li,Yihe Wang,Jianwen Chen,Zongping He

doi:10.1155/2016/4869891

Junqiu Li, Yihe Wang + Show 2 more

Open Access

https://doi.org/10.1155/2016/4869891

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Abstract

Accurate control of oil pressure of wet-clutch is of great importance for improving shift quality. Based on dynamic models of two-gear planetary transmission and hydraulic control system, a trajectory tracking model of oil pressure was built by sliding mode control method. An experiment was designed to verify the validity of hydraulic control system, through which the relationship between duty cycle of on-off valve and oil pressure of clutch was determined. The tracking effect was analyzed by simulation. Results showed that oil pressure could follow well the optimal trajectory and the shift quality was effectively improved.

Highlights

Electric vehicles are gaining popularity because of high energy efficiency, low emission, and diversified energy source [1]
Two-gear planetary transmission and wet-clutch can be well matched with high speed motor, which has good application prospect and practical value in electric vehicles
It is required that vehicles should be smooth and steady in shift process; the friction elements of clutch should work with low heat load

Summary

Introduction

Electric vehicles are gaining popularity because of high energy efficiency, low emission, and diversified energy source [1]. It is required that vehicles should be smooth and steady in shift process; the friction elements of clutch should work with low heat load. These two targets are both affected by clutch toque, which is decided by oil pressure if the physical structure of clutch is confirmed [2, 3]. In previous researches, based on optimal control theory, with shifting jerk and sliding friction work selected as control targets, the authors have obtained optimal trajectory of oil pressure in shift process [4]. Due to the complex nonlinear characteristics of clutch, changeable liquid viscosity, and variable external load, there is a great necessity to work out a strategy with strong robustness and preferable tracking quality. Controller is designed to track optimal trajectory of shifting oil pressure in this paper, the accuracy and robustness of control system are well improved

Structure and Dynamic Modeling of Two-Gear Transmission

Sliding Mode Controller Design of Combined Clutch

At4 12

Result

Conclusion