scholarly journals Adaptive emergency braking control with underestimation of friction coefficient

2002 ◽  
Vol 10 (3) ◽  
pp. 381-392 ◽  
Author(s):  
J. Yi ◽  
L. Alvarez ◽  
R. Horowitz
Keyword(s):  
Friction Coefficient ◽  
Emergency Braking ◽  
Braking Control

scholarly journals Advanced Emergency Braking Controller Design for Pedestrian Protection Oriented Automotive Collision Avoidance System

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Guo Lie ◽  
Ren Zejian ◽  
Ge Pingshu ◽  
Chang Jing
Keyword(s):  
Collision Avoidance ◽  
Controller Design ◽  
Sliding Mode ◽  
Vulnerable Groups ◽  
Control Effect ◽  
Longitudinal Dynamics ◽  
Emergency Braking ◽  
Collision Avoidance System ◽  
Braking Control ◽  
Single Neuron Pid

Automotive collision avoidance system, which aims to enhance the active safety of the vehicle, has become a hot research topic in recent years. However, most of the current systems ignore the active protection of pedestrian and other vulnerable groups in the transportation system. An advanced emergency braking control system is studied by taking into account the pedestrians and the vehicles. Three typical braking scenarios are defined and the safety situations are assessed by comparing the current distance between the host vehicle and the obstacle with the critical braking distance. To reflect the nonlinear time-varying characteristics and control effect of the longitudinal dynamics, the vehicle longitudinal dynamics model is established in CarSim. Then the braking controller with the structure of upper and lower layers is designed based on sliding mode control and the single neuron PID control when confronting deceleration or emergency braking conditions. Cosimulations utilizing CarSim and Simulink are finally carried out on a CarSim intelligent vehicle model to explore the effectiveness of the proposed controller. Results display that the designed controller has a good response in preventing colliding with the front vehicle or pedestrian.

Autonomous Emergency Braking Control Based on Hierarchical Strategy Using Integrated-Electro-Hydraulic Brake System

2017 ◽  
Author(s):  
Xiangkun He ◽  
Xuewu Ji ◽  
Kaiming Yang ◽  
Yulong Liu ◽  
Jian WU ◽  
...  
Keyword(s):  
Brake System ◽  
Emergency Braking ◽  
Hydraulic Brake ◽  
Braking Control

scholarly journals Comparisons Between Braking Experiments and Longitudinal Train Dynamics Using Friction Coefficient and Braking Pressure Modeling in a Freight Train

2020 ◽  
Vol 14 (1) ◽  
pp. 154-163
Author(s):  
Don Bum Choi ◽  
Rag-Gyo Jeong ◽  
Yongkook Kim ◽  
Jangbom Chai
Keyword(s):  
Friction Coefficient ◽  
Time Integration ◽  
Expansion Method ◽  
Dynamics Simulation ◽  
Dynamic Simulations ◽  
Freight Train ◽  
Emergency Braking ◽  
Braking Distance ◽  
Train Dynamics ◽  
Simulation Results

Background: This paper describes the predictions and validation of the pneumatic emergency braking performance of a freight train consisting of a locomotive and 20 wagons, generally operated in Korea. It suggests the possibility of replacing the expensive and time-consuming train running tests with longitudinal train dynamic simulations. Methods: The simulation of longitudinal train dynamics of a freight train uses the time integration method of EN 14531. For reasonable simulation results, the characteristics of the train and brake equipment must be considered. For the train characteristics, specifications provided by the vehicle manufacturer are used. The braking characteristics are analyzed by friction coefficient tests and a braking pressure model. The friction coefficients of a locomotive and wagons are tested with a dynamo test bench and statistically expanded to account for variability. Freight trains should take into account the braking delay time. To reflect this in the simulation, the brake cylinder pressure pattern model uses pressures and exponential empirical equations measured at selective positions in a train of 50 vehicles. The simulation results are validated in comparison with those of the braking tests of a freight train consisting of 1 locomotive and 20 wagons. Results: The results of the longitudinal dynamics simulation show very similar results to the running test results based on the speed profile and braking distance. Conclusion: In particular, the statistical expansion method of the friction coefficient enables robust prediction of the distribution of the braking distance. The simulation can reduce or make up for costly and time-consuming repeated braking tests and reduce the risks that may arise during testing.

scholarly journals Sensorless Driving/Braking Control for Electric Vehicles

Actuators ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 22
Author(s):  
En-Ping Chen ◽  
Jiangfeng Cheng ◽  
Jia-Hung Tu ◽  
Chun-Liang Lin
Keyword(s):  
Electric Vehicles ◽  
Pulse Width Modulation ◽  
Functional Flexibility ◽  
Emergency Braking ◽  
Braking System ◽  
System A ◽  
High Speeds ◽  
Antilock Braking System ◽  
Braking Control ◽  
The Cost

A sensorless driving/braking control system for electric vehicles is explained in the present paper. In the proposed system, a field-oriented control (FOC) was used to integrate driving and braking controls in a unified module for reducing the cost of hardware and simultaneously incorporating functional flexibility. An antilock braking system can swiftly halt a vehicle during emergency braking. An electromagnetic reverse braking scheme that provided retarding torque to a running wheel was developed. The scheme could switch the state of the MOSFETs used in the system by alternating the duty cycle of pulse width modulation to adjust the braking current generated by the back electromotive force (EMF) of the motor. In addition, because the braking energy required for the electromagnetic braking scheme is related only to the back EMF, the vehicle operator can control the braking force and safely stop an electric vehicle at high speeds. The proposed integrated sensorless driving and electromagnetic braking system was verified experimentally.

scholarly journals Estimation of Brake Friction Coefficient for Blending Function of Base Braking Control

2017 ◽  
Vol 10 (3) ◽  
pp. 774-785 ◽  
Author(s):  
Vincenzo Ricciardi ◽  
Dzmitry Savitski ◽  
Klaus Augsburg ◽  
Valentin Ivanov
Keyword(s):  
Friction Coefficient ◽  
Braking Control ◽  
Blending Function
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