Active Steering and Driving/Braking Coupled Control Based on Flatness Theory and a Novel Reference Calculation Method

Yuqiong Wang,Yi Xu,Shuming Shi,Song Gao,Pengwei Wang

doi:10.1109/access.2019.2959941

Yuqiong Wang, Yi Xu + Show 3 more

Open Access

https://doi.org/10.1109/access.2019.2959941

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Journal: IEEE Access	Publication Date: Jan 1, 2019
Citations: 8	License type: CC BY 4.0

Affiliation: Shandong University of Technology, Jilin University

Abstract

Vehicle handing stability under the combined acceleration steering and braking steering conditions has a great impact on the vehicle safety. Therefore, the coupled steering and driving/braking stability control is essential. Thus, a novel controller based on differential flatness and vehicle stability region is proposed. First, the reference vehicle state variables are calculated and the vehicle stability region is established based on vehicle dynamics and bifurcation analysis. Then, the flatness-based controller is designed which can ensure the vehicle handing stability by controlling the vehicle states approaching their references. Based on the driver preview model, the vehicle can keep good path tracking effect by tracking the lateral deviation. The simulation results of the double lane change tests show that the proposed control method can ensure both the vehicle handing stability and the path tracking effect. Compared to vehicle equipped with the integration of active front steering and direct yaw moment control, vehicle controlled by flatness-based controller performs better in both handing stability and path tracking.

Highlights

The vehicle may lose its stability and cause heavy traffic accidents when running in high speed steering, acceleration steering or braking steering
This paper proposes a coupled steering and driving/ breaking stability control method based on differential flatness theory and preview follower theory
OPEN-LOOP TEST In order to analyze the effectiveness of the proposed integrated control system under the open-loop experiment, a cycle sinusoidal of 30deg/0.25Hz steering wheel angel input is given, the vehicle speed is set at 30m/s and the and the tire–road adhesion coefficient is set to 0.85

Summary

INTRODUCTION

The vehicle may lose its stability and cause heavy traffic accidents when running in high speed steering, acceleration steering or braking steering. The longitudinal wind resistance is considered in vehicle system modeling and the new reference calculation method based on road information and nonlinear dynamics bifurcation theory is proposed. VEHICLE STEERING AND DRIVING/BREAKING MODEL The planar motion stability is mainly considered than roll or pitch stability since the study is aimed at the coupled longitudinal and lateral control. The lateral and longitudinal forces of front and rear wheels can be calculated according to the vehicle dynamics model as follows: Fsf. Flr = (−I wwr − Tbr )/Rw where Cf and Cr represent the lateral stiffness of front and rear axles, respectively. We take (2), (3) and (4) into (1), the differential equation of the three-degree-of-freedom dynamics model can be obtained as (5): mvx This dynamics model (5) introduces both steering angle of front wheel and the longitudinal driving torque and braking torque of the wheels. The target path and the reference vehicle variables which can evaluate the vehicle handing stability should be studied firstly

REFERENCE PATH

REFERENCE LONGITUDINAL VELOCITY

REFERENCE YAW RATE

SIMULATION RESULTS AND ANALYSIS

CONCLUSION