• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.1
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• pp.19-27
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• 2017

In this paper, a simulator hardware and control design for an electronic parking brake (EPB) are proposed for emergency vehicle braking when the hydraulic break and anti-lock brake systems (ABS) fail to function. EPB systems are designed specifically for park braking and are usually installed on the rear wheels. However, in an emergency situation when all vehicle brake systems fail, the EPB can be utilized to stop the vehicle and track the target slip ratio as the ABS. This paper analyzed the non-linear EBP of the type of motor on caliper (MoC) based on experiments. A simulator hardware is also designed to validate the performance of the designed EPB controller in terms of braking distance and performance in tracking the target slip ratio. Through the experimental analysis, it is confirmed that a sliding mode controller can be applied on a non-linear EPB to track the target slip ratio.

• Journal of Drive and Control
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• v.16 no.3
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• pp.23-32
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• 2019

This study proposed a fault tolerant control algorithm for electro-hydraulic brake systems where permanent magnet synchronous motor (PMSM) drive is adopted to boost the braking pressure. To cope with motor position sensor faults in the PMSM drive, a braking pressure controller based on an open-loop speed control method for the PMSM was proposed. The magnitude of the current vector was determined from the target braking pressure, and motor rotational speed was derived from the pressure control error to build up the braking pressure. The position offset of the pump piston resulting from a leak in the hydraulic system is also compensated for using the open-loop speed control by moving the piston backward until it is blocked at the end of stroke position. The performance and stability of the proposed controller were experimentally verified. According to the results, the control algorithm can be utilized as an effective means of degraded control for electro-hydraulic brake systems in the case that a motor position sensor fault occurs.

• Transactions of The Korea Fluid Power Systems Society
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• v.5 no.4
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• pp.1-9
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• 2008

In this paper, an energy regeneration algorithm is proposed to make the maximum use of the regenerative braking energy for a parallel hybrid electric vehicle(HEV) equipped with a continuous variable transmission(CVT). The regenerative algorithm is developed by considering the battery state of charge(SOC), vehicle velocity and motor capacity. The hydraulic module consists of a reducing valve and a power unit to supply the front wheel brake pressure according to the control algorithm. In order to evaluate the performance of the regenerative braking algorithm and the hydraulic module, a hardware-in-the-loop simulation (HILS) is performed. In the HILS system, the brake system consists of four wheel brakes and the hydraulic module. Dynamic characteristics of the HEV are simulated using an HEV simulator. In the HEV simulator, each element of the HEV powertrain such as internal combustion engine, motor, battery and CVT is modelled using MATLAB/$Simulink^{(R)}$. In the HILS, a driver operates the brake pedal with his or her foot while the vehicle speed is displayed on the monitor in real time. It is found from the HILS that the regenerative braking algorithm and the hydraulic module suggested in this paper provide a satisfactory braking performance in tracking the driving schedule and maintaining the battery state of charge.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.4
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• pp.335-341
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• 2010

The electric braking system obtains its braking force by a motor instead of the hydraulic brake which has been used in conventional automobile systems. Electric braking system is consisted of fewer numbers of components than hydraulic braking system, and it has effects of improved response and reduced braking distance for the ABS(Anti-lock Brake System) and ESC(Electronic Stability Control). This paper presents the BLAC motor drive system for Electro-Magnetic Brake(EMB). Proposed control system consists of the power converter for driving a motor and the digital control system for speed control, and the vector control is applied for fast torque response. It is verified through the simulation using Matlab/Simulink and experiment that the proposed BLAC drive system can be applied to EMB.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.145-154
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• 2006

Each part of drum brake system is loaded by continual mechanical force and thermal force every time of braking, so enough strength and stability are required. Thermal characteristic is one of the important factors in drum brake systems design. This paper presents the thermal performance such as temperature distribution and thermal contact stress of drum brake system considering several braking patterns; 80th heat braking test mode, heat fade braking test mode, general road mode, steep slope road mode and off road mode. Transient heat transfer analysis and Thermo elastic contact analysis is executed to obtain the temperature distribution, and to evaluate thermal stress of drum brake by using ABAQUS/Standard code. This procedure of analysis can effectively be used to improve the quality problem of brake system and to get design guideline of the new product.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.152-167
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• 2001

Recently safety systems for the commercial vehicle have been rapidly developed. However, we still have many problems in the vehicle stability and the braking performance. Especially, a commercial vehicle may meet a dangerous braking condition when the vehicle is lightly loaded or empty and when the road is wet or slippery. Under these conditions, the truck can spin out or the tractor can jackknife or the trailer can swing out. To design the air brake system for the commercial vehicle, since the air brake system has many design variables, there must have been intensive researches on a method how to prevent dynamic instability and how to maximize the vehicle deceleration. In this study, mathematical models about the tractor-semitrailer and the air brake system including an ABS controller have been constructed for computer simulation. Also, simple examples are applied to show the usefulness of the program. Designers can use this simulation program for understanding the braking characteristics such as trajectory, braking distance, longitudinal deceleration, lateral deceleration, and yaw rate on various road conditions.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.88-93
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• 1993

This paper introduces an ARV(Autonomous Road Vehicle) system which can run on orads without help of a driver by detecting road boundaries through computer vision. This vehicle can also detect obstacles in front through sonar sensors and infrared sensors. This system largely consists of a handle steering module and a braking module. From road boundaries, the steering module determines handle turn angle. The braking module stops or decelerates to avoid collision depending on the relative speeds and distance to the obstacles detected by different sensors. This ARV system has been implemented in a small jeep and can run 30-40 km/h city traffic. In this paper, we illustrate the structure of the ARV systems and its operation principle.

• Transactions of The Korea Fluid Power Systems Society
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• v.7 no.2
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• pp.7-12
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• 2010

In these days, the researches about hybrid and fuel cell electric vehicles are actively performed due to the environmental contamination and resource exhaust. Specially, the technology of regenerative braking, converting heat energy to electric energy, is one of the most effective technologies to improve fuel economy. This paper developed a regenerative braking control algorithm that is considered vehicle stability. The vehicle has a inline motor at front drive shaft and has a EHB(Electo-hydraulic Brake) system. The control logic and regenerative braking control algorithm are analyzed by MATLAB/Simulink. The vehicle model is carried out by CarSim and the driving simulation is performed by using co-simulation of CarSim and MATLAB/Simulink. From the simulation results, a regenerative braking control algorithm is verified to improve the vehicle stability as well as fuel economy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.517-523
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• 2004

Recently, wheel slip controllers with controlling the wheel slip directly has been studied using the brake-by-wire actuator. The wheel slip controller is able to control the braking force more accurately and can be adapted to various different vehicles more easily than the conventional ABS systems. The wheel slip controller requires the information about the tire braking force and road condition in order to achieve the control performance. In this paper, the tire braking forces are estimated considering the variation of the friction between brake pad and disk due to aging of the brake, moisture on the contact area or heating. In addition, the road friction coefficient is estimated without using tire models. The estimated performance of tire braking forces and the road friction coefficient is evaluated in simulations.