• Title, Summary, Keyword: Slip Ratio Control

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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
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    • v.12 no.2
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    • pp.21-26
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    • 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.

Experimental Research on Finding Best Slip Ratio for ABS Control of Aircraft Brake System (항공기용 제동장치의 ABS 제어를 위한 최적 슬립율 결정에 관한 시험적 연구)

  • Yi, Miseon;Song, Wonjong;Choi, Jong Yoon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.5
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    • pp.597-607
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    • 2017
  • The general control method for Anti-lock Brake System(ABS) is that the wheel slip ratio is observed and the braking force is controlled in real time in order to keep the wheel slip ratio under the value of the best slip ratio. When a wheel runs on the state of the best slip ratio, the ground friction of the wheel approaches the highest value. The value of best slip ratio, theoretically, is known as the value between 10 and 20 % and it is dependant on the ground condition such as dry, wet and ice. It is an important parameter for the braking performance and affects the braking stability and efficiency. In this thesis, an experimental method is suggested, which is a reliable way to decide the best slip ratio through dynamo tests simulating aircraft taxiing conditions. The obtained best slip ratio is proved its validity by results of aircraft taxiing tests.

ABS Sliding Mode Control considering Optimum Road Friction Force of Tyre (타이어의 최적 노면 마찰력을 고려한 ABS 슬라이딩 모드 제어)

  • Kim, Jungsik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.1
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    • pp.78-85
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    • 2013
  • This paper presents the sliding mode control methods for anti-lock brake system (ABS) with the friction force observer. Using a simplified quarter car model, the sliding mode controller for ABS is designed to track the desired wheel slip ratio. Here, new method to find the desired wheel slip ratio which produces the maximum friction force between road and tire is suggested. The desired wheel slip ratio is varying according road and tire conditions to produce maximum friction force. In order to find optimum desired wheel slip ratio, the sliding mode observer for friction force is used. The proposed sliding mode controller with observer is evaluated in simulation, and the control design is shown to have high performance on roads with constant and varying adhesion coefficients.

Optimal Wheel Slip Control for Vehicle Stability During Cornering (선회시 차량의 주행 안정성을 위한 최적의 구동차륜 슬립제어)

  • 박종현;김찬영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.4
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    • pp.190-198
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    • 1997
  • Traction control systems are used to prevent the wheel slippage and to maximize the traction force. A new scheme of controlling the wheel slip during cornering by varying the slip ration as a function of the slip angle is proposed and dynamically simulated with the model of a front wheel driven passenger vehicle. Simulation results show that the proposed scheme is superior to conventional ones based on the fixed slip ratio during cornering and lane changes.

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A Study of ADS Slip Ratio Control using Solenoid Valve (전자밸브를 이용한 ABS 슬립율 제어에 관한 연구)

  • Choi, Jong-Hwan;Kim, Sung-Su;Yang, Soon-Yong;Park, Sung-Tae;Lee, Jin-Kul
    • Proceedings of the KSME Conference
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    • pp.676-681
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    • 2001
  • ABS is a safety device, which adds hydraulic system to the existing brake system to prevent wheel from locking, so we can obtain maximum braking force on driving. The hydraulic system to control braking pressure consists of sol-flow type using solenoid valve, flow control valve or consists of sol-sol type using two solenoid valve. In this paper, the hydraulic system in ABS is composed of sol type using a 3port-2position solenoid valve, and vehicle system is composed of 1/4 vehicle model. And slip ratio is controlled using PWM (Pulse-Width-Modulation) control algorithm. Braking friction coefficient and tracking friction coefficient which are described by slip ratio's function have maximum value when slip ratio has its value from 0.1 to 0.3. And slip ratio is controlled constantly in this boundary value even in the variation of road's condition in some boundary.

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A Study on Optimal Design of Automotive Hydraulic Control System for Slip Ratio Control (슬립율 제어를 위한 자동차용 유압 조절시스템의 최적 설계에 관한 연구)

  • 김대원;김진한;최석창
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.10
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    • pp.41-50
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    • 1998
  • In this study, to investigate a characteristics of slip ratio control of H.C.U for ABS, half car model tester were developed and a new H.C.U. was compactly designed comparing to the commercical H.C.U. for ABS. In half car model tester, variable inertia wheel has been used to load the car weights and braking forces according to the road surface conditions which were realized by pneumatic cylinder. And solenoid valves using P.W.M. (Pulse Width Modulation) method were installed in the new H.C.U The slip ratio characteristics of tire had been measured using half car model tester and the results were used in the control simulation for a new H.C.U.

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Position Control of Wafer Lift Pin for the Reduction of Wafer Slip in Semiconductor Process Chamber

  • Koo, Yoon Sung;Song, Wan Soo;Park, Byeong Gyu;Ahn, Min Gyu;Hong, Sang Jeen
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.4
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    • pp.18-21
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    • 2020
  • Undetected wafer slip during the lift pin-down motion in semiconductor equipment may affect the center to edge variation, wafer warpage, and pattern misalignment in plasma equipment. Direct measuring of the amount of wafer slip inside the plasma process chamber is not feasible because of the hardware space limitation inside the plasma chamber. In this paper, we demonstrated a practice for the wafer lift pin-up and down motions with respect to the gear ratio, operating voltage, and pulse width modulation to maintain accurate wafer position using remote control linear servo motor with an experimentally designed chamber mockup. We noticed that the pin moving velocity and gear ratio are the most influencing parameters to be control, and the step-wised position control algorithm showed the most suitable for the reduction of wafer slip.

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Robust Wheel Slip Controller for Vehicle Stability Control

  • Kwak, Byung-Hak;Park, Young-Jin
    • 제어로봇시스템학회:학술대회논문집
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    • pp.174.4-174
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    • 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.

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A FUZZY LOGIC CONTROLLER DESIGN FOR VEHICLE ABS WITH A ON-LINE OPTIMIZED TARGET WHEEL SLIP RATIO

  • Yu, F.;Feng, J.-Z.;Li, J.
    • International Journal of Automotive Technology
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    • v.3 no.4
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    • pp.165-170
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    • 2002
  • For a vehicle Anti-lock Braking System (ABS), the control target is to maintain friction coefficients within maximum range to ensure minimum stopping distance and vehicle stability. But in order to achieve a directionally stable maneuver, tire side forces must be considered along with the braking friction. Focusing on combined braking and turning operation conditions, this paper presents a new control scheme for an ABS controller design, which calculates optimal target wheel slip ratio on-line based on vehicle dynamic states and prevailing road condition. A fuzzy logic approach is applied to maintain the optimal target slip ratio so that the best compromise between braking deceleration, stopping distance and direction stability performances can be obtained for the vehicle. The scheme is implemented using an 8-DOF nonlinear vehicle model and simulation tests were carried out in different conditions. The simulation results show that the proposed scheme is robust and effective. Compared with a fixed-slip ratio scheme, the stopping distance can be decreased with satisfactory directional control performance meanwhile.

Predicting Maximum Traction for Improving Traversability of Unmanned Robots on Rough Terrain (무인 로봇의 효율적 야지 주행을 위한 최대 구동력 추정)

  • Kim, Ja-Young;Lee, Ji-Hong
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.10
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    • pp.940-946
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    • 2012
  • This paper proposes a method to predict maximum traction for unmanned robots on rough terrain in order to improve traversability. For a traction prediction, we use a friction-slip model based on modified Brixius model derived empirically in terramechanics which is a function of mobility number $B_n$ and slip ratio S. A friction-slip model includes characteristics of various rough terrains where robots are operated such as soil, sandy soil and grass-covered soil. Using a friction-slip model, we build a prediction model for terrain parameters on which we can know maximum static friction and optimal slip with respect to mobility number $B_n$. In this paper, Mobility number $B_n$ is estimated by modified Willoughby Sinkage model which is a function of sinkage z and slip ratio S. Therefore, if sinkage z and slip ratio are measured once by sensors such as a laser sensor and a velocity sensor, then mobility number $B_n$ is estimated and maximum traction is predicted through a prediction model for terrain parameters. Estimation results for maximum traction are shown on simulation using MATLAB. Prediction Performance for maximum traction of various terrains is evaluated as high accuracy by analyzing estimation errors.