• Title, Summary, Keyword: Braking systems

Search Result 230, Processing Time 0.032 seconds

MAXIMUM BRAKING FORCE CONTROL UTILIZING THE ESTIMATED BRAKING FORCE

  • Hong, D.;Hwang, I.;SunWoo, M.;Huh, K.
    • International Journal of Automotive Technology
    • /
    • v.8 no.2
    • /
    • pp.211-217
    • /
    • 2007
  • The wheel slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS (Anti-lock Brake System) systems. In realizing the wheel slip control systems, real-time information such as the tire braking force at each wheel is required. In addition, the optimal target slip values need to be determined depending on the braking objectives such as minimum braking distance and stability enhancement. In this paper, a robust wheel slip controller is developed based on the adaptive sliding mode control method and an optimal target slip assignment algorithm is proposed for maximizing the braking force. An adaptive law is formulated to estimate the braking force in real-time. The wheel slip controller is designed based on the Lyapunov stability theory considering the error bounds in estimating the braking force and the brake disk-pad friction coefficient. The target slip assignment algorithm searches for the optimal target slip value based on the estimated braking force. The performance of the proposed wheel slip control system is verified in HILS (Hardware-In-the-Loop Simulator) experiments and demonstrates the effectiveness of the wheel slip control in various road conditions.

Implementation and Tests of Antilock Braking Algorithm for a heavy vehicle

  • Lee, Ki-Chang;Jeongwoo Jeon;Donha Hwang;Kim, Yongjoo
    • 제어로봇시스템학회:학술대회논문집
    • /
    • /
    • pp.67.4-67
    • /
    • 2002
  • Antilock brake System (ABS) is a essential safety equipment for modern vehicles. It prevents wheels from being locked-up when emergency braking of a vehicle is required. So it can improves directional stability of the vehicle, shortens stopping distance. Heavy Vehicles such as trucks and buses use mainly pneumatic pressures for their braking systems, where pneumatic modulators control the flow rate of compressed air thus braking pressures in the wheels. In this paper, a antilock braking algorithm which is suitable for heavy vehicles was developed. This algorithm uses limit cycle of wheels and is implemented in the ABS ECU. The developed algorithm and ECU were tested in the labo..

  • PDF

Maximum Braking Force Control Using Wheel Slip Controller and Optimal Target Slip Assignment Algorithm in Vehicles (휠 슬립 제어기 및 최적 슬립 결정 알고리즘을 이용한 차량의 최대 제동력 제어)

  • Hong Dae-Gun;Hwang In-Yong;SunWoo Myoung-Ho;Huh Kun-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.30 no.3
    • /
    • pp.295-301
    • /
    • 2006
  • The wheel slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS systems. In order to achieve the superior braking performance through the wheel-slip control, real-time information such as the tire braking force at each wheel is required. In addition, the optimal target slip values need to be determined depending on the braking objectives such as minimum braking distance, stability enhancement, etc. In this paper, a robust wheel slip controller is developed based on the adaptive sliding mode control method and an optimal target slip assignment algorithm. An adaptive law is formulated to estimate the longitudinal braking force in real-time. The wheel slip controller is designed using the Lyapunov stability theory and considering the error bounds in estimating the braking force and the brake disk-pad friction coefficient. The target slip assignment algorithm is developed for the maximum braking force and searches the optimal target slip value based on the estimated braking force. The performance of the proposed wheel-slip control system is verified In simulations and demonstrates the effectiveness of the wheel slip control in various road conditions.

Anti-lock Braking System for Commercial Vehicles with Pneumatic Brake System by Using Slip Ratio (슬립률을 이용한 상용차용 공압식 브레이크 기반 ABS 알고리즘 개발)

  • Kim, Jayu;Kwon, Baeksoon;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
    • /
    • v.12 no.2
    • /
    • pp.21-26
    • /
    • 2020
  • This paper presents an anti-lock braking system for commercial vehicles with pneumatic brake system by using slip ratio. By virtue of system reliability, most commercial vehicles adopt pneumatic brake system. However, pneumatic brake systems control is more difficult than hydraulic systems due to a longer time delay and the system nonlinearity. One of the major factors in generating braking forces is the wheel slip ratio. Accordingly, the proposed ABS strategy employs the slip ratio threshold-based valve on/off control. This threshold-based algorithm is simple but effective to control the pneumatic brake systems. The control performance of the proposed algorithm has been validated via simulation studies using MATLAB/Simulink and Trucksim. The results show ABS by using slip ratio reduces the braking distance and improves vehicle control.

HILS of the Braking System of a High Speed Train (고속전철 제동시스템의 HILS)

  • Hwang, Won-Ju;Kang, Chul-Goo
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.7 no.5
    • /
    • pp.432-437
    • /
    • 2001
  • Korea High Speed Train(KHST) is supposed to run up 350km/h, in which the braking system has a crucial role for the safety of the train. In the design st데 of the braking system, its very hard to ac-quire information data for design guidelines. A HILS(Hardware-In-the-Loop Simulation) system can be used to get design data which could simulate the braking system of the real train in real-time. In this paper, cars are modelled including car dynamics, brake blending algorithms, pneumatic actuator dynamics, the models of each braking devices, adhesive coefficients, and soon. Real-time braking time, distance, and other design parameters are simulated using a DSP board and C language which shows the validity of the proposed method.

  • PDF

Influence of the Braking Time on the Soundness of Ventilated Disc Brake Systems (제동시간이 통풍형 디스크 브레이크 시스템의 건전성에 미치는 영향)

  • Gwak, Woo-Gyeong;Hong, Chang-Ki;Kim, Youn-Jea
    • Journal of Auto-vehicle Safety Association
    • /
    • v.8 no.1
    • /
    • pp.7-12
    • /
    • 2016
  • In order to analyze the soundness of ventilated disc brake systems, numerical study was performed with various vane shapes. In particular, two different vane type, and the braking time from 3.0 s to 4.5s with the interval of 0.5s were considered. Transient temperature distributions on the ventilated disc brake assembly were calculated using ANSYS CFX ver. 16.1. To elucidate the soundness of ventilated disc brake systems, moreover, the heat transfer coefficients were evaluated. Results were graphically depicted with different geometrical vane configurations and braking time.

Robust Wheel Slip Controller for Vehicle Stability Control

  • Kwak, Byung-Hak;Park, Young-Jin
    • 제어로봇시스템학회:학술대회논문집
    • /
    • /
    • pp.174.4-174
    • /
    • 2001
  • Vehicle stability control system can enhance the vehicle stability and handling in the emergency situations through the control of traction and braking forces at the individual wheels. To achieve the desired performance, the wheel slip controller manages the hydraulic braking system to generate the desired braking force at each wheel. In this study, we propose the wheel slip controller for the generation of the braking forces based on multiple sliding mode control theory with the pulse width modulation. The proposed controller follows to the slip ratio and the brake pressure the desired ones so that the vehicle stability controller can Intervene braking force at each wheel. We show the validity and usefulness of the proposed controller through computer simulations.

  • PDF

Robust Wheel Slip Control for Brake-by-Wire System (Brake-by-Wire 시스템을 위한 강인한 휠 슬립 제어)

  • Hong Daegun;Huh Kunsoo;Kang Hyung-Jin;Yoon Paljoo;Hwang Inyong
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.13 no.3
    • /
    • pp.102-109
    • /
    • 2005
  • Wheel-slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS systems. But, in order to achieve the superior braking performance through the wheel-slip control, real-time information such as the tire braking force is required. For example, in the case of EHB (Electro-Hydraulic Brake) systems, the tire braking force cannot be measured directly, but can be approximated based on the characteristics of the brake disk-pad friction. The friction characteristics can change significantly depending on aging of the brake, moisture on the contact area, heat etc. In this paper, a wheel slip The proposed wheel slip control system is composed of two subsystems: braking force monitor and robust slip controller In the brake force monitor subsystem, the tire braking forces as well as the brake disk-pad friction coefficient are estimated considering the friction variation between the brake pad and disk. The robust wheel slip control subsystem is designed based on sliding mode control methods and follows the target wheel-slip using the estimated tire braking forces. The proposed sliding mode controller is robust to the uncertainties in estimating the braking force and brake disk-pad friction. The performance of the proposed wheel-slip control system is evaluated in various simulations.

Capacitance Estimation Method of DC-Link Capacitors for BLDC Motor Drive Systems

  • Moon, Jong-Joo;Kim, Yong-Hyu;Park, June-Ho;Kim, Jang-Mok
    • Journal of Electrical Engineering and Technology
    • /
    • v.11 no.3
    • /
    • pp.653-661
    • /
    • 2016
  • This paper proposes a capacitance estimation method of the dc-link capacitor for brushless DC motor (BLDCM) drive systems. In order to estimate the dc-link capacitance, the BLDCM is operated in quadrant-II or -IV among four-quadrant operation. Quadrant-II and -IV are called reverse braking and forward braking, respectively. During the braking operation of the BLDCM, the capacitor is charged by the phase current and then the voltage is increased during the braking operation time. The capacitor current and voltage can be obtained by using the phase current sensor of BLDCM and the dc-link voltage sensor. The capacitance and be easily obtained by the voltage equation of the capacitor. The proposed method guarantees the reliable and simple calculation of the dc-link capacitance without additional hardware system except several the sensors already installed for the motor control system. The effectiveness of the proposed method is verified through both the simulation and experimental results.

Absolute Vehicle Speed Estimation using Neural Network Model (신경망 모델을 이용한 차량 절대속도 추정)

  • Oh, Kyeung-Heub;Song, Chul-Ki
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.19 no.9
    • /
    • pp.51-58
    • /
    • 2002
  • Vehicle dynamics control systems are. complex and non-linear, so they have difficulties in developing a controller for the anti-lock braking systems and the auto-traction systems. Currently the fuzzy-logic technique to estimate the absolute vehicle speed is good results in normal conditions. But the estimation error in severe braking is discontented. In this paper, we estimate the absolute vehicle speed by using the wheel speed data from standard 50-tooth anti-lock braking system wheel speed sensors. Radial symmetric basis function of the neural network model is proposed to implement and estimate the absolute vehicle speed, and principal component analysis on input data is used. Ten algorithms are verified experimentally to estimate the absolute vehicle speed and one of those is perfectly shown to estimate the vehicle speed with a 4% error during a braking maneuver.