Improved AEB algorithm combined with estimating the adhesion coefficient of road ahead and considering the performance of EHB

Abstract

This paper proposes an improved autonomous emergency braking (AEB) algorithm intended for intelligent vehicle. Featuring a combination with the estimation of road adhesion coefficient, the proposed approach takes into account the performance of electronic hydraulic brake. In order for the accurate yet fast estimate of road ahead adhesion coefficient, the expectation maximization framework is applied depending on the reflectivity of ground extracted by multiple beams lidar in four major steps, which are the rough extraction of ground points based on 3 σ criterion, the accurate extraction of ground points through principal component analysis (PCA), the main distribution characteristics of ground as extracted using the expectation maximum method (EM) and the estimation of road adhesion coefficient via joint probability. In order to describe the performance of EHB, the response characteristics, as well as the forward and adverse models of both braking pressure and acceleration are obtained. Then, with two typical roads including single homogeneous road and fragment pavement, the safe distance of improved AEB is modeled. To validate the algorithm developed in this paper, various tests have been conducted. According to the test results, the reflectivity of laser point cloud is effective in estimating the road adhesion coefficient. Moreover, considering the performance of EHB system, the improved AEB algorithm is deemed more consistent with the practicalities.

Road Adhesion Coefficient Estimation Based on Second‐Order Linear Extended State Observer

“…where y and u are the output and input variables of the controller; f(y(t), _ y(t), 1) , w(t)) is a nonlinear time-varying unknown dynamics including internal dynamics of the system and external interference; w (t) is the external disturbance, which can be the time-varying or stationary; b is the control gain. Te equation (33) can be written as…”

“…Te real-time, fast, and accurate identifcation of road adhesion coefcient is one of the hot spots and difcult issues in the feld of automobile intelligence, which directly afects vehicle active safety, vehicle state estimation accuracy, and vehicle handling stability [1][2][3]. Te electronic control technology and control strategy of active safety system are developed rapidly, which can regulate the force between the tire and road surface.…”

Design of advanced emergency braking system based on vehicle-road cooperation

“…The distance-based safety model in triggering all levels of warning and braking mainly relies on the comparison with the relative distance D between the self vehicle and the collision risk and the braking control trigger distance threshold, so the accuracy of the braking control trigger distance threshold is the key to the distance-based safety model braking control collision avoidance. [8]However, under the actual operating conditions of vehicles, there are often complex and variable road conditions and meteorological conditions, so the distance-based safety model control parameters need to be optimized and calculated for various scenarios.…”

Evaluation of autonomous emergency braking by using a theoretical formula and dual cameras

“…Woo et al 13 authored “Design and simulation of a vehicle test bed based on Intelligent Transport Systems (ITS).” Specifically, ITS-based intelligent vehicle test bed was constructed, satisfying the requirements of ISO/TC204 standards, to meet the growing demand of testing and verification for ADAS and ITS systems. Peng et al 14 authored “AEB effectiveness research methods based on reconstruction results of truth vehicle-to-two wheel (TW) accidents in China,” Zeng et al 15 authored “Improved AEB algorithm combined with estimating the adhesion coefficient of road ahead and considering the performance of electro-hydraulic brake,” Kinosada et al 16 authored “Trusting other vehicles’ automatic emergency braking decreases self-protective driving,” and Ahmad et al 17 authored “Simulation and experimental investigation of vehicle braking system employing a fixed caliper based electronic wedge brake.” Finally, Soule et al 18 authored “Testing an automated collision avoidance and emergency braking system for buses.”…”