• 대한안전경영과학회지
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• 제3권2호
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• pp.181-188
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• 2001

This paper deals with a newly developed direction indicator system of a car which displays left turn and U-turn signal differently, so that the following driver can identify the intent of the next car ahead easily. In general, when a car want to change its direction, the driver move the blinker lever below the steering wheel up or down. However, as the left turn and U-turn signal are the same, there always be the risk of rear-end collision by misinterpreting U-turn signal as left turn signal. In this paper, a new direction indicator system which differentiates left turn and U-turn signal is developed. The left turn signal is the same as before, but when a driver want to U-turn, an additional U-turn signal blinks at the rear of the car. By identifying the direction signals clearly, the developed system is expected to alleviate the risk of car accident.

• International Journal of Automotive Technology
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• 제6권6호
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• pp.615-623
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• 2005

In this research, an effective technique was examined to improve the drift running performance. Concretely, the driver model by which the counter steer was done was assumed to the model by which the vehicle body slip angle (and the vehicle body slip angle velocity) was feed back. Next, the effectiveness of the system which added the assist steer angle corresponding to the steering wheel angle velocity to a front wheel steer angle was clarified as a drift running performance improvement technique of the vehicle. As a result, because the phase advances when the differentiation steer assistance is added, it has been understood to be able to cover the delay of the counter steer when the drift running. Therefore, it has been understood that the drift control does considerably easily. Moreover, it has been understood that the differentiation steer assistance acts effectively at the drift cornering by which the drift angle is maintained in cornering and the severe lane change with a drift at a situation. That is, it was understood to be able to settle to the drift angle of the aim quickly at the time of the drift cornering because the delay of the control steer angle of the counter steer was improved. Moreover, it was understood for the transient overshoot of the vehicle tracks to be able to decrease, and to return to the state of stability quickly at the severe lane change.

• 한국자동차공학회논문집
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• 제15권5호
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• pp.180-187
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• 2007

This paper presents a mathematical vehicle model that is designed to analyze the dynamic performance and to develop various safety control systems. Wheel slip controllers for ABS is also formulated to improve the vehicle response and to increase the safety on slippery road. Validation of the model and controller is performed by comparison with a commercial software package, CarSim. The result shows that performances of developed vehicle model are in good accordance with those of the CarSim on various driving conditions. Developed ABS controller is applied to the vehicle model and CarSim model, and it achieves good control performance. ABS controller improves lateral stability as well as longitudinal one when a vehicle is in turning maneuver on slippery road. A driver model is also designed to control steer angle of the vehicle model. It also shows good performance because the vehicle tracks the desired lane very well.

• 전자공학회논문지
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• 제53권4호
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• pp.149-155
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• 2016

본 논문에서는 운전자의 체중 이동을 활용한 메카넘 휠 기반 전방향 전동 보드 제어 방법을 제안한다. 운전을 위한 별도의 운전 장치를 사용하지 않으며, 다수의 센서를 활용하여 측정한 체중 분포로부터 무게 중심의 위치를 구하여 전방향 전동 보드의 병진 운동과 회전 운동의 3 자유도 운전 명령을 생성한다. 체중 이동은 운전 명령으로 반영됨과 동시에 관성력을 극복하기 위한 운전자의 동작과 일치하여 직관적인 장점이 있다. 전체 제어 구조를 제시하며, 실험에 적용하여 제안된 방식의 타당성을 확인한다.

• 한국산학기술학회논문지
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• 제18권11호
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• pp.697-704
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• 2017

본 연구는 영업운행 중인 고속열차의 진동 문제를 고찰하고, 이를 개선하기 위하여 진행되었다. 먼저 고속열차의 진동 수준을 알기 위하여 차체 진동가속도에 대한 측정이 수행되었다. 측정결과 운전실이 객차보다 진동이 크며, 열차 후미로 갈수록 진동이 더 커졌다. 운전실 및 객차 모두 수직방향 진동이 횡방향 진동에 비해서 크며, 콘크리트 구간에 비해 자갈궤도에서 진동의 최대값이 크다. KTX-산천 진동 경향과 개선점을 도출하기 위하여 동역학 해석을 수행하였다. 해석결과는 시험 결과와 유사하였으며, 객차 양 끝단의 단부객차 상부와 동력차량의 진동을 저감시킬 필요가 있었다. 객차의 진동을 저감하기 위하여 KTX-호남(200호대) 차량은 4가지 개선 설계를 수행하였고, 이 중 KTX-산천에 적용할 수 있는 방법을 해석에 적용하였을 때, 정상구간에서는 2.2%, 분기기구간에서는 11% 정도 진동이 감소할 것으로 예상되었다. 동력차량의 진동 저감을 위해 2차 코일스프링의 강성을 감소시키고, 2차 수직댐퍼의 댐핑계수를 증가시키는 방안을 제안하였다. 현가장치의 불량, 오조립 등 성능저하가 차체 및 대차의 진동을 증가시키는 것을 시운전 결과와 해석결과를 통하여 살펴보았으며, 현가장치 올바른 유지보수가 차량 진동을 저감시킴을 알 수 있었다. 차륜 마모에 대한 적절한 관리는 운행 효율 및 차체 진동저감에 중요한 역할을 하며, 현재 차륜 프로파일을 변경하여 차륜 삭정간의 주행거리를 늘리려는 연구가 진행 중이다.

• 대한인간공학회지
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• 제35권1호
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• pp.11-27
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• 2016

Objective: The purpose of this study was to develop and evaluate high technology adaptive driving controls, such as mini steering wheel-lever system and joystick system, for the people with physical disabilities in the driving simulator. Background: The drivers with severe physical disabilities have problems in operation of the motor vehicle because of reduced muscle strength and limited range of motion. Therefore, if the remote control system with driver-by-wire technology is used for adaptive driving controls for people with physical limitations, the disabled people can improve their quality of life by driving a motor vehicle. Method: We developed the remotely controlled driving simulator with drive-by-wire technology, e.g., mini steering wheel-lever system and joystick system, in order to evaluate driving performance in a safe environment for people with severe physical disabilities. STISim Drive 3 software was used for driving test and the customized Labview program was used in order to control the servomotors and the adaptive driving devices. Thirty subjects participated in the study to evaluate driving performance associated with three different driving controls: conventional driving control, mini steering wheel-lever controls and joystick controls. We analyzed the driving performance in three different courses: straight lane course for acceleration and braking performance, a curved course for steering performance, and intersections for coupled performance. Results: The mini steering wheel-lever system and joystick system developed in this study showed no significant statistical difference (p>0.05) compared to the conventional driving system in the acceleration performance (specified speed travel time, average speed when passing on the right), steering performance (lane departure at the slow curved road, high-speed curved road and the intersection), and braking performance (brake reaction time). However, conventional driving system showed significant statistical difference (p<0.05) compared to the mini steering wheel-lever system or joystick system in the heading angle of the vehicle at the completion point of intersection and the passing speed of the vehicle at left turning. Characteristics of the subjects were found to give a significant effect (p<0.05) on the driving performance, except for the braking reaction time (p>0.05). The subjects with physical disabilities showed a tendency of relatively slow acceleration (p<0.05) at the straight lane course and intersection. The steering performance and braking performance were confirmed that there was no statistically significant difference (p>0.05) according to the characteristics of the subjects. Conclusion: The driving performance with mini steering wheel-lever system and joystick control system showed no significant statistical difference compared to conventional system in the driving simulator. Application: This study can be used to design primary controls with driver-by-wire technology for adaptive vehicle and to improve their community mobility for people with severe physical disabilities.

• 제어로봇시스템학회논문지
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• 제21권2호
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• pp.95-101
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• 2015

In this paper, we develop a sliding mode control for steering wheel angle control based on torque overlay in order to resolve the problem of previous methods for Electric Power Steering (EPS) systems in the Lane Keeping System (LKS) of autonomous vehicles. For the controller design, we propose a 2nd order model of the electric power steering system in an autonomous LKS. The desired state model is designed to prevent a rapid change of the steering wheel angle. The sliding mode steering wheel angle controller is developed for the robustness of the disturbance. Since the proposed method is designed based on torque overlay, torque integration with basic functions of the EPS system for the steering wheel angle control is available for the driver's convenience. The performance of the proposed method was validated via experiments.

• 한국도로학회논문집
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• 제20권1호
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• pp.9-18
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• 2018

PURPOSES : In this research, the initiation and development of corrugation on a gravel road with certain wheel and boundary conditions were evaluated using a coupled discrete-element method (DEM) with multibody dynamics (MBD). METHODS : In this study, 665,534 particles with a 4-mm diameter were generated and compacted to build a circular roadbed track, with a depth and width of 42 mm and 50 mm, respectively. A single wheel with a 100-mm diameter, 40-mm width, and 0.157-kg mass was considered for the track. The single wheel was set to run slowly on the track with a speed of 2.5 rad/s so that the corrugation was gradually initiated and developed without losing contact between the wheel and the roadbed. Then, the shape of the track surface was monitored, and the movement of the particles in the roadbed was tracked at certain wheel-pass numbers to evaluate the overall corrugation initiation and development mechanism. RESULTS : Two types of corrugation, long wave-length and short wave-length, were observed in the circular track. It seems that the long wave-length corrugation was developed by the longitudinal movement of surface particles in the entire track, while the short wave-length corrugation was developed by shear deformation in a local section. Properties such as particle coefficients, track bulk density, and wheel mass, have significant effects on the initiation and development of long-wave corrugation. CONCLUSIONS : It was concluded that the coupled numerical method applied in this research could be effectively used to simulate the corrugation of a gravel road and to understand the mechanism that initiates and develops corrugation. To derive a comprehensive conclusion for the corrugation development under various conditions, the driver's acceleration and deceleration with various particle gradations and wheel-configuration models should be considered in the simulation.

• 대한인간공학회지
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• 제31권5호
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• pp.637-646
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• 2012

Objective: The aim of this study was to develop the adaptive device for severe physical disabilities using smart device in the driving simulator and its performance evaluation. Development of appropriate driving adaptive device for the people with serious physical limitation could contribute to maintain their community mobility. Background: There is lack of adaptive driving devices for the people with disabilities in Korea. However, if smart device systems like iPod and iPhone are used for driving a car, the people with serious physical limitations can improve their community mobility. Method: Both gyroscope and accelerometer from iPod were used to measure the tilted angle of the smart device for driving. Customized Labview program was also used to control three axis motors for steering wheel, accelerator and brake pedals. Thirteen subjects were involved in the experiment for performance evaluation of smart device in simulator. Five subjects had driver licenses. Another four subjects did not have driver licenses. Others were people with disabilities. Results: Average driving score of the normal group with driver license in the simulator increased 46.6% compared with the normal group without driver license and increased 30.4% compared with the disabled group(p<0.01). There was no significant difference in the average driving score between normal group without driver license and disabled group(p>0.05). Conclusion: The normal group with driver license showed significantly higher driving score than other groups. The normal group without driver license and disabled group could improve their driving skills with training in simulator. Application: If follow-up studies would be continued and applied in adapted vehicle for on road environment, many people with more severe disabilities could drive and improve the quality of life.

• 한국융합학회논문지
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• 제9권8호
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• pp.179-184
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• 2018

자동차의 구동방식은 전륜구동, 후륜구동, 4륜구동의 방식이 있다. 구동방식에서 운전자가 원하는 방향으로 전환하는 것과 바퀴에 동력을 전달하여 구동하는 두 가지의 역할을 수행하는데 있어 가장 중요한 부품이 등속 조인트이다. 도로상에서 주행 시에는 노면의 상태에 따라서 동력을 전달하는 부품들에 충격이 가해질 수 있다. 본 연구에서는 각각 샤프트의 길이가 다른 3개의 등속 조인트 각 모델들은 CATIA로 모델링하였고 ANSYS를 이용하여 구조 및 피로해석을 수행하였다. 본 연구 결과로는 Model 2가 다른 모델 대비 뛰어난 내구성을 가짐을 알 수 있었다. 이러한 결과를 이용하여 충격에 대한 내구성을 가지는 등속 조인트 설계를 할 때에 유용한 자료가 될 것이라고 사료되며, 등속 조인트의 디자인을 융합기술에 접목하여 미적 감각을 나타낼 수 있다.