• 대한의용생체공학회:의공학회지
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• 제38권1호
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• pp.32-42
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• 2017

The aim of this study was to evaluate driving performance of Healthy and disabled groups (with or without driver's license) to control steering wheel by using steering assistive devices in the driving simulator. The persons with partial loss of use of all four limbs have problems in operation of the motor vehicle because of functional loss to operate steering wheel. Therefore, if steering assistive devices for grasping the steering wheel are used to control the vehicle on the road in persons with disabilities, the disabled persons can improve mobility in their community life by driving a motor vehicle safely. Ten healthy subjects (with or w/o driver's license) and ten subjects with physical disabilities (with or w/o driver's license) were involved in this study to evaluate driving performance to operate steering wheel by using four types of steering assistive devices (Single-pin, V-grip, Palm-grip, Tri-pin) in driving simulator. STISim Drive 3 software was used to test the steering performance in four scenarios: straight road at low and high speed of vehicle (40 km/h and 80 km/h), curved road at low and high speed of vehicle (40 km/h and 80 km/h). This study used two-way ANOVA in order to compare the effects of two factors (type of steering assistive device and subject group) in the three dependent variables of driving performance (the lateral position of vehicle, standard deviation of lateral position representing the variation of the left and right movement of the vehicle and the number of line crossing). The mean values of the three dependent variables (lateral position, standard deviation of lateral position, the number of line crossing) of steering performance were statistically significantly smaller for the healthy or disabled groups with driver's license than the other groups without driver's license on the curved road at high speed of vehicle compared to low speed of vehicle.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.151-153
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• 1993

This paper proposes a novel motor drive system for the electric vehicle. In this paper, four-wheel-direct-drive type electric vehicle system is designed and the theoretical and experimental analysis of the system is investigated. The concept of steering not with steering the wheels but with the difference of the motor torque fives the flexibility of the vehicle design and, allows the omission of the differential gear, transmission gear, and drive axles. Thus the proposed system gives the space between wheels and improves the driver's steering performance.

• 대한토목학회논문집
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• 제33권4호
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• pp.1611-1617
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• 2013

동절기 도로구간에서 차량의 운행가능성 혹은 등판 가능성 정보는 교통 운영에 매우 중요한 요소이다. 특히, 빙설 구간을 운행할 경우 차량과 노면의 마찰력은 차량의 유형, 도로 기하구조의 특성 및 노면의 특성에 따라 다양하게 나타난다. 일반적으로 노면 결빙(적설)구간에서 트럭과 같은 후륜구동 차량은 전륜구동이나 4륜 구동 차량보다 마찰력이 낮으며, 갑작스런 강설시 이러한 차량의 무리한 도로 운행은 도로의 대규모 혼잡을 발생시키는 주요 원인으로 알려져 왔다. 따라서 도로의 기하구조 및 노면 특성과 차량의 유형에 기반한 실시간 도로 등판가능성 지표의 구축은 동절기 차량 및 도로의 운영 가능성 판단에 기반이 될 것으로 판단되다. 이러한 배경 하에 본 연구는 동절기 도로의 기하구조 및 노면 특성과 차량의 유형에 따른 도로의 운행가능성 지표를 구축방향을 제시하고자 하였다. 비록 제시된 지표는 국내 도로와 차량을 통해 구축된 결과는 아니지만, 향후 동절기 도로 및 차량 운영을 위한 지표 수립의 연구에 유용하게 활용될 것으로 기대된다.

• 드라이브 ㆍ 컨트롤
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• 제17권1호
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• pp.27-36
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• 2020

The aim of this study is to design a simulation model for an electric All-Wheel-Drive (AWD) tractor to evaluate the performance of the selected component and agricultural work ability. The electric AWD tractor consists of four motors independently for each drive wheel, and each motor is combined with an engine generator, a battery pack, and reducers. The torque data of a 78 kW-class tractor was measured during plow tillage and driving operation to develop a workload cycle. A simulation model was developed by using commercial software, Simulation X, and it used the workload as the simulation condition. As a result of simulation analysis, the drive system, including an electric motor and reducers, was able to cope with high load during plow tillage. The SOC (State of Charge) level was influenced by the output power of the motor, and it was maintained in the range of 50~80%. The fuel consumed by the engine was about 18.23 L during working on a total of 8 fields. The electric AWD tractor was able to perform agricultural work for about 7 hours. In the future study, the electric AWD tractor will be developed reflecting the simulation condition. Research on the comparison between the simulation model and the electric AWD tractor should be performed.

• 한국정밀공학회지
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• 제17권2호
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• pp.80-88
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• 2000

This paper presents a method to optimize the bump steer characteristics (the change of toe angle with vertical wheel travel) with respect to hard points in the double wishbone front suspension of the four-wheel-drive vehicle using the design of experiment, multibody dynamics simulation, and optimum design program. Front and rear suspensions are modeled as the interconnection of rigid bodies by kinematic joints and force elements using DADS. The design variables with respect to the kinematic characteristics are obtained through the experimental design sensitivity analysis. An object function is defined as the area of absolute differences between the desired and experimental toe angle. By the design of experiment and regression analysis, the regression model function of bump steer characteristics is extracted. The design variables that make the toe angle optimized are selected using the optimum design program DOT. The lane change simulations and tests of the full vehicle models are implemented to evaluate the improvement of vehicle handling performances by the optimization of front bump steer characteristics. The results of the lane change simulations show that the vehicle with optimized bump steer has the weaker understeer tendency than the vehicle with initial bump steer.

• 전자공학회논문지S
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• 제34S권4호
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• pp.12-24
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• 1997

An intelligent steering control system is designed for the steering control of a 4 wheel drive (4WD) electric vehicles without steering mechanism, where the vehicle is assumed to have 3 degree of freedom and input-output feedback linearization is employed. Especially, a fuzzy-rule-based side force estimator is suggested to avoid uncertain highlynonlinearexpression sof relations between side forces and their factors. Also, aneural-network-based predictive compensator is additionally utilized for the vehicle model to be correctly controlled with unstructured uncertainties. The proposed overall control system is numerically shown to be robust against drastic change of the external environments.

• Journal of Advanced Marine Engineering and Technology
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• 제24권6호
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• pp.155-163
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• 2000

A technology of full time four wheel drive(4WD) vehicle has been improved greatly, and the market share of full time 4WD has been extended steadily in recent days. The transfer case is an essential element in the 4WD automobile. In this paper, the details of electronically controlled transfer case is described. In order to achieve easy shifting, the shifting, the developed system automate the conversion of "$4\times2\longleftrightarrow4\times4(H)\longleftrightarrow4\times4(L)$". Furthmore, this system employs an chain drive type instead of gear drive type for drive type and synchromesh type instead of constant-mesh type for gear mesh type. Therefore, the developed transfer case is accomplished light-weight, low noise, and compact.d compact.

• 한국산림과학회지
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• 제84권2호
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• pp.218-225
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• 1995

이 논문에서는 임업용 트랙터의 집재작업 분석에 요구되는 역학분석모델을 제시하고 사례분석을 통해 적용성을 검토하였다. 역학분석모델은 크게 견인목의 역학구조해석모델, 차량하중분석모델 및 주행중인 차량의 구동력과 저항력 분석모델의 3부분으로 구성되어 있다. 사례분석에서는 가상적인 집재작업 시나리오를 만들어 역학적으로 중요하거나 혹은 집재생산성에 중요한 인자들에 대한 영향력분석을 통해 모델의 적용성을 검토하였다. 사례분석은 1) 당김줄을 견인목에 묶는 방법이 견인력에 미치는 영향, 2)주행속도 및 견인목 하중이 차륜의 동력요구에 미치는 영향, 3) 2륜구동과 4륜구동 트랙터의 견인작업 수행 성능 비교에 관한 내용을 포함한다.

• 한국지능시스템학회논문지
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• 제26권2호
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• pp.153-159
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• 2016

본 논문는 대각선 주행이 가능한 전방향 퍼스널 모빌리티의 메커니즘을 제안한다. 현대 사회에서 이동성은 인간의 기본적인 활동을 영위하는데 수반되는 전제조건이다. 퍼스널 모빌리티는 새로운 이동수단으로 자동차와 동일한 바퀴구조를 가지고 있으며 이동성 역시 자동차와 유사하다. 최근 노약자와 교통약자를 위한 퍼스널 모빌리티도 4륜 전동카트가 널리 보급되었다. 일반적으로 전동카트는 주행경로를 변경할 때 차체는 조향하는 방향으로 회전하며 이 때 곡률반경에 따른 충분한 공간을 확보해야 한다. 제안하는 퍼스널 모빌리티는 대각선 주행이 가능해지면서 이동성의 한계를 극복할 수 있다. 또한 주행경로에 장애물이 존재하거나 건물내부와 같은 좁은 공간에서도 주행이 가능해지면서 교통약자도 다양한 주행환경을 극복할 수 있다. 이 논문에서는 제안하는 퍼스널 모빌리티의 메커니즘과 개발한 퍼스널 모빌리티의 조향성능을 실험하고 대각선 주행이 가능함을 입증한다.

• 한국자동차공학회논문집
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• 제8권2호
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• pp.120-128
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• 2000

At the initial design stage of a new vehicle, the chassis layout has the most important influence on the overall vehicle performance. Most chassis designers have achieved the target performances by trial and error method as well as individual knowhow. Accordingly, a general procedure for determining the optimum location of suspension hard points with respect to the kinematic characteristics needs to be developed. In this paper, a method to optimize the toe angle in the double wishbone type front suspension of the four-wheel-drive vehicle is presented using the design of experiment, multibody dynamic simulation, and optimum design program. The handling performances of two full vehicle models having the initial and optimized toe angle are compared through the single lane change simulation. The sensitive design variables with respect to the kinematic characteristics are selected through the experimental design sensitivity analysis using the perturbation method. An object function is defined in terms of the toe angle among those kinematic characteristics. By the design of experiment and regression analysis, the regression model function of toe angle is obtained. The design variables which make the toe angle optimized ae extracted using the optimum design program DOT. The single lane change simulation and test of the full vehicle model are carried out to survey the handling performances of vehicle with toe angle optimized. The results of the single lane change simulation show that the optimized vehicle has the more improved understeer tendency than the initial vehicle.