COMPARISON OF RIDE COMFORTS VIA EXPERIMENT AND COMPUTER SIMULATION

W. S. YOO,S. J. PARK,D. W. PARK,M. S. KIM,O. K. LIM,W. B. JEONG 한국자동차공학회 2006 International journal of automotive technology Vol.7 No.3

In this paper, the ride comfort from a computer simulation was compared to the experimental result. For measuring ride comfort of a passenger car, acceleration data was obtained from the floor and seat during highway running with different speeds. The measured acceleration components were multiplied by the proper weighting functions, and then summed together to calculate overall ride values. Testing several passenger cars, the ride comforts were compared. In order to investigate the effect of vibration signals on the steering wheel, an apparatus to measure the vibrations and weighting functions on the steering wheel were designed. The effect of the steering accelerations on the ride comfort were investigated and added for the overall ride comfort. For the computer simulations, Korean dummy models were developed based on the Hybrid III dummy models. For the Korean dummy scaling, the national anthropometric survey of Korean people was used. In order to compare and check the validity of the developed Korean dummy models, dynamic responses were compared to those of Hybrid III dummy models. The computer simulation using the MADYMO software was also compared to the experimental results.

한국형 고속철도 승차감의 감성 모형 개발

이주환,이철,김인기,윤명환,Lee, Joo-Hwan,Lee, Cheol,Kim, In-Ki,Yun, Myung-Hwan 대한인간공학회 2007 大韓人間工學會誌 Vol.26 No.1

KTX (Korea Train eXpress) is launched as the $5^{th}$ develop a ride-comfort model for high-speed rail pasengers using structural equation model (SEM). Both qualitative and quantitative factors affecting ride-comfort were investigated, and employed to construct a comprehensive ride-comfort model. The SEM model was built with twenty measurement variables and seven latent variables for the evaluation of ride-comfort of high-speed train passenger. A total of six hundreds thirty two subjects participated in the evaluation using face-to-face survey method. As a result, the proposed SEM model model fitnes (GFI=0.93). According to the results, overall ride-comfort was significantly affected by the seat-, fatigue-, interior-related, and customer satisfaction variables such as fare. Among the engineering design variables of high-speed train, seat-related variables were identified as critical factors of the ride-comfort. It is expected that the result of this study could be useful for the enhancement of ride comfort in next generation KTX.

극치이론을 이용한 표본기반의 차량승차감 신뢰성 설계

최찬규(Chan Kyu Choi),유홍희(Hong Hee Yoo) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

The properties of the system parameters in a vehicle have uncertainties due to material irregularity, manufacturing tolerances or any other uncertain factors. Since the uncertainties of the system parameters lead to the uncertainty of the vehicle ride comfort, the uncertainties of the system parameters are direct causes of declining reliability of the vehicle ride comfort. So, the uncertainty of the vehicle ride comfort should be analyzed and considered for reliable design of the vehicle ride comfort. In order to analyze the uncertainty of the vehicle ride comfort accurately, exact probability distributions of the uncertain system parameters are needed. In most of practical situations, however, obtaining the exact probability distributions of the uncertain system parameters is almost impossible because of the limited time and cost. For that case, the reliability of the vehicle ride comfort cannot be obtained. Therefore, the reliability of the vehicle ride comfort should be estimated using limited samples of the uncertain system parameters. For the purpose, samplebased reliability estimation method employing an extreme value theory was proposed in this paper. Using the proposed reliability estimation method, reliability design of the vehicle ride comfort was conducted.

Ride Comfort Measuring Approach of Tilting Train based on Bio Parameter

KwangSoo-Shin,YoungBum-Lee,YongSoo-Song,SungHo-Han,MyoungHo-Lee 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

The Korea is consisted of 70% mountain terrain and at existing railroad, which is many of curve railroad segment naturally. The tilting train cancels centrifugal force of the curve railroad segment at sway and need not decelerate speed of tilting train in the curve railroad segment by the tilting of train body. As you get a hunch as term "tilting", the biggest advantage of tilting train is that the train body is tilted when the tilting train is driven. The TTX which is Korean tilting train is acquired tilting angle range from -8° to maximum 8° and can get high speed at railroad which shared with low speed train. But the tilting of passenger compartment gives negative influence by decreasing ride comfort. Presently, the measuring method of train ride comfort is mainly based of vibration, that is, mechanical parameter. This paper would like to show the ride comfort using the biological parameter by measuring R-R interval (Peak to Peak Interval) of ECG(Electrocardiogram), event number and measuring the event area of GSR(Garvanic Skin Response), the number of zero-crossing and magnitude of EMG (Electromyogram) of Human Model. This method is more direct, based on human body response, than mechanical parameter method. In this experiment, we are supposed to know excitement, awakening, muscle fatigue, through examining bio-signals. Considering pleasance and stability, elements of ride comfort, the pleasance is restricted thoroughly and our research will just only think aspect of stability. The research about ride comfort of TTX ultimately must make advance ride comfort of TTX.

설계변수의 산포를 고려한 차량 승차감의 강건최적설계

송필곤(Song, Pil-Gon),유홍희(Yoo, Hong-Hee) 한국소음진동공학회 2008 한국소음진동공학회 논문집 Vol.18 No.12

Vehicle vibration mostly originates from the road excitation and causes discomfort, fatigue and even injury to a driver. Vehicle ride comfort is one of the most important performance indices to achieve a high-quality vehicle design. Since design parameter variations inevitably result in the vehicle ride comfort variance, the variance characteristics should be analyzed in the early design stage of the vehicle. The vehicle ride comfort is often defined by an index which employs a weighted RMS value of the acceleration PSD of a seat position. The design solution is obtained through two steps in this study. An optimization problem to obtain a minimum ride comfort index is solved first. Then another optimization problem to obtain minimum variance of the ride comfort index is solved. For the optimization problems, the equations of motion and the sensitivity equations are derived basing on a 5-DOF vehicle model. The numerical results show that an optimal solution for the minimum ride comfort is not necessarily same as that of the minimum variance of the ride comfort.

공차의 영향을 고려한 차량 승차감의 강건최적설계

송필곤(Pil Gon Song),Maksym Spiryagin,유홍희(Hong Hee Yoo) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

Vehicle vibration mostly originates from the road excitation and causes discomfort, fatigue and even injury to a driver. Vehicle ride comfort is one of the most important performance indices to achieve a high-quality vehicle design. Since design parameter tolerances inevitably result in the vehicle ride comfort variance, the variance characteristics should be analyzed in the early design stage of the vehicle. The vehicle ride comfort is often defined by an index which employs a weighted RMS value of the acceleration PSD of a seat position. The design solution is obtained through two steps in this study. An optimization problem to obtain a minimum ride comfort index is solved first. Then another optimization problem to obtain minimum variance of the ride comfort index is solved. For the optimization problems, the equations of motion and the sensitivity equations are derived basing on a 5-DOF vehicle model. The numerical results show that an optimal solution for the minimum ride comfort is not necessarily same as that of the minimum variance of the ride comfort.

승차감 분석 및 객관평가 해법, 랜덤 노면 DRA

김승한(Seunghan Kim) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

Ride comfort is a performance that combines the human emotional response to the low-frequency behavior of the vehicle on the road. Subjective rating has been carried out in the vehicle development process, and due to the uncertainty of the subjective rating, there has been a limit in that it was not possible to quickly and clearly approach a solution for improving ride comfort performance. Ride comfort is the only performance index that is difficult to derive a solution directly from the commonly known task of measuring vehicle behavior. And ride comfort is a continuously difficult performance index in vehicle development as long as the vehicle is driving on the road. This paper proposes random road DRA as the solution for the analysis and objective rating of ride-comfort.

COMPARISON OF RIDE COMFORTS VIA EXPERIMENT AND COMPUTER SIMULATION

Yoo, W.S.,Park, S.J.,Park, D.W.,Kim, M.S.,Lim, O.K.,Jeong, W.B. The Korean Society of Automotive Engineers 2006 International journal of automotive technology Vol.7 No.3

In this paper, the ride comfort from a computer simulation was compared to the experimental result. For measuring ride comfort of a passenger car, acceleration data was obtained from the floor and seat during highway running with different speeds. The measured acceleration components were multiplied by the proper weighting functions, and then summed together to calculate overall ride values. Testing several passenger cars, the ride comforts were compared. In order to investigate the effect of vibration signals on the steering wheel, an apparatus to measure the vibrations and weighting functions on the steering wheel were designed. The effect of the steering accelerations on the ride comfort were investigated and added for the overall ride comfort. For the computer simulations, Korean dummy models were developed based on the Hybrid III dummy models. For the Korean dummy scaling, the national anthropometric survey of Korean people was used. In order to compare and check the validity of the developed Korean dummy models, dynamic responses were compared to those of Hybrid III dummy models. The computer simulation using the MADYMO software was also compared to the experimental results.

현가장치 내 감쇠 제어를 이용한 캡슐트레인 승차감 향상 연구

이진호,임정열,유원희,이관섭 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.10

In this study, damping control devices were applied to the suspension system of a capsule train, and the effects were investigated to improve the ride comfort. The superconductor electrodynamic suspension (SC-EDS) method is used for the capsule train levitation. This method has advantages such as no gap control and a large gap. However, the SC-EDS method has disadvantages such as large gap variation and small damping characteristics against outer vibration, which causes degradation of the ride comfort. In this study, the damping control devices in the primary and secondary suspension were considered to improve the ride comfort in the capsule train. Damping control devices in the primary and secondary suspension can reduce the vibration transmission from outer disturbances to the bogie and from the bogie to the car body, respectively. Simulations for dynamic characteristics analyses were conducted based on the capsule train dynamic model to investigate the effects of the damping control devices on the ride comfort. As a result, it was confirmed that the ride comfort requirements according to the ISO standard can be satisfied by applying the damping control in the capsule train suspension. 본 연구에서는 캡슐트레인의 승차감 향상을 위하여 캡슐트레인 모델 내의 현가장치에 감쇠 제어 장치를 적용하고 그 효과를 검토하였다. 캡슐트레인의 부상 방식으로 사용되는 초전도 유도 반발식 부상은 별도의 부상제어가 필요 없고 부상 공극이 큰 장점이 있다. 하지만, 본 부상 방식은 공극 변화량이 크고 외부로부터 유입되는 진동에 대한 작은 감쇠 특성으로 인해 캡슐트레인의 승차감을 저하시키는 단점이 있다. 본 연구에서는 캡슐트레인의 승차감 향상을 위해서 1차 및 2차 현가장치 내에 적용되는 감쇠 제어 장치를 고려하였다. 1차 현가장치에 적용되는 감쇠 제어 장치는 외란에 의해 발생하는 진동이 대차로 전달되는 것을 감소시키는 역할을 하고, 2차 현가장치 적용되는 감쇠 제어 장치는 대차의 진동이 차체로 전달되는 것을 감소시키는 역할을 한다. 감쇠 제어가 승차감에 미치는 효과를 검토하기 위하여 캡슐트레인 모델을 기반으로 한 동특성 해석 시뮬레이션을 수행하였다. 검토 결과, 현가장치 내 감쇠 제어를 통해 ISO 기준의 승차감 규격을 만족할 수 있음을 확인하였다.

차량 승차감에 미치는 공차의 영향 분석을 위한 해석적 방법

김범석(Beomseok Kim),김봉수(Bongsoo Kim),유홍희(Honghee Yoo) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Drivers are exposed to the vehicle vibration which mostly originates from the interaction between the road and the vehicle. Vibration can cause discomfort, fatigue, and sometimes even injury to a driver. So, the vehicle ride comfort is one of the most important performance indices to achieve a qualitatively excellent vehicle design. From the previous research works, it is obvious that the ride comfort is affected by various parameters of a vehicle model. Therefore. the effects of the parameters on the ride comfort need to be evaluated quantitatively based on the whole-body vibration of the vehicle. An analytical method to analyze the tolerance effects of major vehicle parameters on the vehicle ride comfort is proposed in this paper. The weighted RMS values of the acceleration PSD of a seat position are employed to define the ride comfort. The equations of motion and the sensitivity equations are derived based on a 5DOF vehicle model.