• 한국자동차공학회논문집
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• 제25권1호
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• pp.103-110
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• 2017

Most commercial vehicles have adopted the hydraulic power steering system. To reduce fuel consumption and to improve steering controllability, a hybrid electric power steering system is being developed for commercial vehicles. In this study, the HILS (Hardware In the Loop Simulation) system equipped with a commercial vehicle hybrid electric power steering system was developed and the vehicle dynamic performance of a truck with the steering system was evaluated. The hybrid electric power steering system is composed of the EHPS motor pump, column mounted EPS system, and ball nut steering gear box for heavy commercial vehicles. The accuracy of vehicle models equipped with the HILS system was verified with comparisons between the simulation results and field test results. The road reaction forces of the steering system were generated from the vehicle model and verified using field test results. Step steering tests using the verified HILS system were carried out and the performance of a newly developed commercial vehicle hybrid electric power steering system was evaluated.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.353-356
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• 1997

Vehicle steering system determines the direction of a vehicle. A manual steering system consists of mechanical connections between the steering wheel and tires. Recent power steering system adds an actuator to help a driver to steer easily at low speed. However, at front collision, the driver can be injured by steering shaft and the power steering pump decreases the engine power. To solve these problems, electronic power steering system which connects the steering wheel and tires with electronic connection is proposed, that has advantages such as decrease of engine load and increase of driver safety reactive. Since the ratio between driver's steering torque and steering torque of tires can be controlled freely, the torque which is delivered from the road to the driver through tires and steering wheel can be reshaped to make the driver feel comfortable. In this paper, the ratio of delivering steering torque and the magnitude of force to be delivered from road to driver has been controlled using fuzzy controller, and it's effectiveness has been shown through simulation results.

• 한국공작기계학회논문집
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• 제14권3호
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• pp.81-86
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• 2005

The agricultural working tractor of this study is equipped with 4 wheel driving system developed in study 1 and 4-type wheel steering system. The wheel steering system has four type of steering methods that are front wheel steering, rear wheel steering, 4 wheel steering with opposite phase, and 4 wheel steering with corresponding phase. This study introduces the hydraulic circuit of the 4-type wheel steering system and the construction of working tractor. Judging from the field test results of the developed working tractor, it is apparent that 4-type wheel steering system has many advantages when driving in a narrow corral.

• 대한기계학회논문집A
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• 제25권6호
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• pp.923-929
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• 2001

Steering system is most important for vehicle in safety and driving feel. However, testing using real car to improve steering feel is often difficult in aspect to repeatability, safety and money. Repeatability in testing steering system is very important because steering feel for driver is variable according to the environment condition. And steering testing of vehicle is so dangerous that driver may not concentrate in testing. In this paper, the steering system simulator using front part of steering and suspension system was developed. We can test the electric power steering system for the light weight vehicle using this simulator cheap, safely and repeatably.

• Journal of Mechanical Science and Technology
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• 제17권9호
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• pp.1261-1267
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• 2003

The Steering system is the most important system for a vehicle, in terms of safety and driving feel. But in many cases, experiments to improve the steering feel using a real vehicle are very difficult in the aspects of repeatability, safety and money. Repeatability in testing steering systems is very important because the steering feel for a driver varies according to the environmental conditions. In addition to that, steering tests using vehicle are so dangerous that the driver might not concentrate on the tests. In this paper, a new steering system simulator using the front part of a steering and suspension system is described. This simulator allows cheap, safe, and repeatable testing of the steering system compared with the real vehicle test.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.129-143
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• 1998

The vibrations of steering wheel are required to be reduced for convenient ride quality and good controllability. This phenomenon, vibration of steering wheel, is occured by interaction with suspension system, steering system, vehicle body, engine/transmission and tire complicately. But reviewing the current research activities, most researches are performed for the vibration analysis of steering wheel with a simple model, and mot easy to be applied to the variation of each component element connected with steering system as well as that of the steering system. In this study, suspension system and steering system are modelled by the T.L.H. coordinate system which is usually used by a passenger car maker. Also, rigid body motions of engine and elastic motions of vehicle body in the previous study are considered. Derive the equation of motion in 29 d.o.f. and the vibration of steering wheel is analyzed numerically and verify the midelling of steering system by comparison with test results for real car. And then, the optimal design values of the engine mount system obtained from the previous study are applied to the verified steering system model and investigate the effects of various engine mount design values on the vibration of steering wheel.

• 한국정밀공학회지
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• 제16권12호
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• pp.214-221
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• 1999

In this research, a power-assisted steering system is modeled as a part of a full vehicle dynamic model. The dynamic model of the steering system incorporates hydraulic and dynamic relations between major parts of a steering system, such as steering column, control valve, rack and pinion gear. Through an experimental setup of the steering system, the steering system model is validated. The steering model is included in a full vehicle dynamic model of a car, where kinematic relations between steering and suspension system are defined, and various simulations are performed to evaluate the performance of steering system in conjunction with overall dynamic performance of the vehicle.

• 동력기계공학회지
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• 제15권6호
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• pp.86-94
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• 2011

In this paper, an electro hydraulic power steering system based on electro hydrostatic actuator (EHA) is proposed. A detailed steering model for the proposed electro hydraulic power steering system including mechanical and hydraulic subsystems is established. A conventional electro hydraulic power steering system is also modeled to evaluate the performance of the proposed power steering system such as responsiveness, assist force, command tracking and steering feel by computer simulation. From the computer simulation results, it is found that the proposed power steering system based on EHA has desirable performance.

• Journal of Mechanical Science and Technology
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• 제16권2호
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• pp.155-164
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• 2002

The power steering system for vehicles is becoming essential for supporting the steering efforts of the drivers, especially for the parking lot maneuver Although hydraulic power steering has been widely used for years, its efficiency is not high enough. The problems associated with a hydraulic howe. steering system can be solved by a motor driven power steering (MDPS) system. In this study, a dynamic model and a control algorithm for the ball screw type of MDPS system have been derived and analyzed by using the method of discrete modeling technology. To improve steering feel and power steering characteristics, two derivative gains are added to the conventional power boosting control algorithm. Through simulations, the effects of the control gain on the steering angle gain were verified in the frequency domain. The steering returnability and steering torque phase lag in on-center handling test were also evaluated in the time domain.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.37-43
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• 2005

A haptic steering system which reflects steering reaction torque has been developed for a fixed base vehicle simulator. The haptic steering system consists of a steering effort sensor, MR-clutch, AC servo motor and controller. In order to generate realistic steering torque feel to driver and at the same time to meet real-time simulation requirement, 3D torque map is constructed by experimental data and torque generation algorithm using the torque map has been also developed. 3D torque map is constructed using curve fitting and interpolation of the measured values of the steering angle, velocity and steering torque from actual slalom test on the proving ground. In order to carry out performance test of the developed haptic steering system, a fixed based vehicle simulator is constructed by integrating real time vehicle dynamics module, VR-video/audio module, and the haptic steering system. Steering torque and steering angle curves have been obtained from virtual testing in the vehicle simulator and performance of the haptic steering system has been evaluated.