• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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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.

• Journal of the Korean Society for Railway
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• v.5 no.1
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• pp.18-25
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• 2002

This paper is to study a comparison of ride stabilities for the guideway vehicle between its three primary steering types; the front-rear wheel steering type, tile independent wheel steering and the front wheel steering. A numerical model were built to investigate various factors to have an influence on the vehicular stability. It was shown that dynamic stabilities of the three types were dependent on the steering gain ratio of front wheel steering to rear. The front-rear wheel steering type was more stable for the value of positive steering gains and the shorter distance between front axle and guide link showed better stabilities. On the contrary, the independent wheel steering was more stable for the value of negative gains and the longer distance between front axle and guide link showed better stabilities. Ride characteristics of he front wheel steering seemed to be found midway. Ride behaviors due to time delay from front steering to rear were very different from steering type to type.

• Journal of Biosystems Engineering
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• v.21 no.1
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• pp.34-43
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• 1996

The present pesticide application technology widely used with a power sprayer in Korea is assessed as the problem awaiting solution in the point of view of its ineffectiveness, inefficiency, and environmental contamination. As one approach to get rid of these problems, the boom spraying with ultra-low volume and precision application technology has been recommended. The study was undertaken to investigate plants damages incurred by the self-propelled boom-sprayer vehicle, to develop the design criteria of vehicle wheel, and to compare plant damages caused by the front wheel steering vehicle, the 4-wheel drive vehicle and the articulated vehicle, by the computer simulation. The experiment showed that the amount of damaged plants incurred by the self-propelled boom sprayer were about 0.29% in average in the field size of 100m$\times$50m(0.5ha), about 60~80% of which recovering while growing. The recommandable wheel size was analyzed to be 70~100cm in diameter, 8~15cm in width from the vehicle-plant-soil relationship. The simulation on damaged plants anticipated to be incurred by various steering vehicles showed that the smaller the turning radius, the lesser the damaged plants within its range of 3~5m. Average plant damage rate by the front wheel steering vehicle, the 4-wheel drive vehicle and articulated vehicle was relatively assessed to be 2 : 1.8 : 1.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1366-1370
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• 2005

As the development of microprocessor technology, electric power steering (EPS) system which uses an electric motor came to use a few years ago. It can solve the problems associated with hydraulic power steering. The motor only operates when steering assistance is needed, so it can save fuel and can reduce weight and cost by eliminating hydraulic pump and piping. As one of performance criteria of EPS systems, the transmissibility from road wheel load to steering wheel torque is considered in the paper. The transmissibility can be studied by fixing the steering wheel and calculating the torque needed to hold the steering wheel from road wheel load. A proportion-plus-derivative control is needed for EPS systems to generate desired static torque boost and avoid transmissibility of fluctuation. A pure proportion control can't satisfy both requirements.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.39-40
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• 2006

The operation of wheel-loader is mainly divided into steering and excavating. The existing wheel-loader is used by handle for steering operation and by joystic for excavating operation. When we do steering and excavating operation simultaneously, we feel so uncomfortable because we have to use handle and joystic simultaneously. Therefore, we need to develop eletro-joystic steering system instead of hydraulic-handle steering system. So we can improve driving convenience in industrial field. This paper analyze spool of steering wheel and joystic and drive open area diagram. As a result, we can know characteristics of each valve before developing new electro-joystic steering system for wheel-loader.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.3
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• pp.71-78
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• 2004

The loader of this study is an agriculture machine for a stock farmer. We has much researched about power train and steering system in order to develop a new stock machine. So, the loader developed in this study has a 4 wheel driving system and a 4-type wheel steering system. Though the technological region is some large and general, these technologies are very important and their technical life may be very long. The power train of the loader is consisted of many units as follows, engine, clutch, transmission, and axles. And, the 4-type wheel steering system is consisted of oil tank, oil pump, steering valve, solenold valve, electronic controller, hydraulic cylinders, and touch sensors. This study shows construction logics of power train and steering system. We could know from many working tests that the developed loader with 4-type steeling system has many advantages when driving in a narrow corral.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.217-223
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• 2003

The power steering system has been adopted in most vehicle system for an easy maneuverability. In this paper, a hydraulic power steering(HPS) model for the computer simulation is developed and used to power steering simulation. The simulation shows that the steering wheel torque with HPS model is less than that without HPS model. In addition, the shimmy vibration at the steering wheel is also simulated and compared to the test data. The lateral displacement of the steering wheel is calculated by imposing the lateral acceleration of the knuckle as a vibration input. The frequency response of the steering wheel is in a good agreement to the test data.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.149-150
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• 2007

By adding Gyro sensor to support the steering wheel angle sensor, an improved functional DR solution is proposed in this paper The proposed angle data algorism is developed based on the steering wheel with Gyro sensor for DR. The Gyro sensor support the error of steering wheel sensor to improve the angle data for the DR algorism.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.1
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• pp.45-55
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• 2013

With the recent advancement of control method and battery technology, the electric vehicle have been researched to replace the conventional vehicle with electric vehicle with the view point of the environmental concerns and energy conservation. An electric vehicle which is equipped with the independent front steering system and in-wheel motors has advantage in terms of control. For example, the different torque which generated by left and right wheels directly can make yaw moment and the independent steering using outer wheel control is able to reduce the sideslip angle. Using of independent steering and driving system, the 4 wheel electric vehicle can improve a performance better than conventional vehicle. In this paper, we consider the method for improving the cornering performance of independent front steering system and in-wheel motor used electric vehicle with the compensated outer wheel angle and direct yaw moment control. Simulation results show that the method can improve the cornering performance of 4 wheel electric vehicle. We also apply the steering motor failure to steer the vehicle turned by the torque difference without steering. This paper describes an independent front steering and driving, consist of three parts; Vehicle Model, Control Algorithm for independent steering and driving and simulation. First, vehicle model is application of TruckSim software for independent front steering and 4 wheel driving. Second, control algorithm describes the reduced sideslip and direct yaw moment method in view of cornering performance. Last is simulation and verification.