• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.986-995
• /
• 2008

This study introduces the testing results of the AL car body which is applied to LRT. The LRT car body is made of aluminum structure materials like a sandwich panel. The static load test was performed to evaluate the structural characteristic and stability of the AL car body. Considering the vertical, compressive, twisting load and 3-point supporting, Bend natural frequency Measurement, Twist natural frequency Measurement type as a testing terms, the structural stability of a car body was evaluated.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.1604-1612
• /
• 2009

This study introduces comparison the testing results of the AL car body which is applied to FSW and GMAW welding method. The car body is made of aluminum structure materials like a sandwich panel. The static load test was performed to evaluate the structural characteristic and stability of the AL car body. Considering the vertical, compressive, twisting load and 3-point supporting, Bend natural frequency Measurement, Twist natural frequency Measurement type as a testing terms, the structural stability of a car body was evaluated.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.8
• /
• pp.2555-2560
• /
• 1996

Inspecting the dimensional accuracy of a car-body in assembly line is a very important process to assure high productivity. Now there exist two common inspecting methods in practice. One is to measure a sampled car-body with three dimensional measuring machine, and the other is to measure car-body with three dimensional measuring machine, and the other is to measure car-body in assembly line using many sensors fixed to a large jig frame. The formal method takes too long to inspect a sampled car-body of a same sort, and cannot therefore give an useful error trend for the whole production. On the other hand, the latter lacks flexibility and is very cost-intensive. By using industrial robots and sensors, an in-line Car-Body Measuring(CBM) system which ensured high flexiblity and sufficient accuracy was developed. This CBM cell operates in real production line and measures the check points by the non-contact type using camera and laser displacement sensor(LDS). This system can handle about 15 Measuring points within a cycle time of 40 seconds. A process computer controls whole process such as data acquisition file handling and data analysis. Robot arms changes in length due to ambient temperature fluctuation affecting the measuring accuracy. To compensate this error, a robot arm calibration process was developed.

• Industrial Engineering and Management Systems
• /
• v.10 no.3
• /
• pp.185-190
• /
• 2011

A driver interacts directly with the car seat at all times. There are ergonomic characteristics that have to be followed to produce comfortable seats. However, most of previous researches focused on either static or dynamic condition only. In addition, research on car seat development is critically lacking although Malaysia herself manufactures its own car. Hence, this paper integrates objective measurements and subjective evaluation to predict seat discomfort. The objective measurements consider both static and dynamic conditions. Steven's psychophysics power law has been used in which after expansion; ${\psi}\;=\;a+b{\varphi}_s^{\alpha}+c{\varphi}_v^{\beta}$ where ${\psi}$ is discomfort sensation, ${\varphi}_s^{\alpha}$ is static modality with exponent ${\alpha}$ and ${\varphi}_v^{\beta}$ is dynamic modality with exponent ${\beta}$. The subjects in this study were local and the cars used were Malaysian made compact car. Static objective measurement was the seat pressure distribution measurement. The experiment was carried out on the driver's seat in a real car with the engine turned off. Meanwhile, the dynamic objective measurement was carried out in a moving car on real roads. During pressure distribution and vibration transmissibility experiments, subjects were requested to evaluate their discomfort levels using vehicle seat discomfort survey questionnaire together with body map diagram. From subjective evaluations, seat pressure and vibration dose values exponent for static modality ${\alpha}$ = 1.51 and exponent for dynamic modality ${\beta}$ = 1.24 were produced. The curves produced from the $E_{q.s}$ showed better $R_{-sq}$ values (99%) when both static and dynamic modalities were considered together as compared to Eq. with single modality only (static or dynamic only R-Sq = 95%). In conclusion, car seat discomfort prediction gives better result when seat development considered both static and dynamic modalities; and using ergonomic approach.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.1139-1143
• /
• 1991

Using industrial robots and sensors, we developed an inline car body inspection system which proposes high flexibility and sufficient accuracy. Car Body Inspection(CBI) cell consists of two industrial robots, two corresponding carriages, camera vision system, a process computer with multi-tasking ability and several LDS's. As industrial robots guarantee sufficient repeatabilities, the CBI cell adopts the concept of relative measurement instead of that of absolute measurement. By comparing the actual measured data with reference data, the dimensional errors of the corresponding points can be calculated. The length of the robot arms changes according to ambient temperature and it affects the measuring accuracy. To compensate this error, a robot arm calibration process was realized. By measuring a reference jig, the differential changes of the robot arms due to temperature fluctuation can be calculated and compensated.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.169-174
• /
• 2007

Adopting articulated bogie system, the HSR350x and KTX have similar physical mechanical characteristic, but they show different dynamic characteristics due to different position of suspensions and those physical properties. The low level vibration frequency which effects on the ride comfort of passengers and the high level vibration frequency which is related to noise of vehicle have been measured by accelerometers mounted on Wheel sets, Bogies and Car bodies to analysis the dynamic characteristics of the High-Speed Trains. The KTX number 36 is utilized to measure the lateral and vertical acceleration value of car body, and total measurement system of HSR350x have been used to acquire acceleration data. The sampling frequency of data is 500Hz generally, but the Car body at TT2 of HSR350 has 1000Hz exceptionally.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.3
• /
• pp.569-574
• /
• 2008

In Because DTV comes to origin of car body shock or brake pedal flutter occurrence in car. This in development of measurement device that can examine this in driver protection dimension or at production early sending of goods visual point purpose of this study have. In this paper, I developed portable Brake Judder measurement system by use of the DTV.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1996.04a
• /
• pp.25-28
• /
• 1996

This paper addresses the issues and difficulties encountered in developing a 12-axis measurement system for the assessment of whole-body vibration exposed from the body contact area. The contents of related survey work and the ideas from Professor Griffin in ISVR, that have led to its successful development, are introduced here. The developed 12-axis measurement system is shown to satisfy the international standards of ISO 2631 and BS 6841 in EC. This system is expected to play a key role in assessing the ride quality of passenger cars that is rapidly becomes much interest in Korean car-makers and tyre-makers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.369-374
• /
• 2004

This study aims to measure an apparent mass of a seated human body at the sitting posture in a passenger car in the frequency range from 1 to 20 Hz and to investigate the dynamic characteristics. Thirty subjects joined the test where eight levels of acceleration from $0.1m/s^2\;to\;2.0m/s^2$ were used to excite seated human body. Most of apparent mass curves showed two peaks in the frequency range of $4\sim9Hz$, first peak was clearer at the contact point of the seat and the hip, and the second one at the contact point of the backrest and the back. Both peak frequencies were found to move down to lower frequencies with increase of acceleration magnitude. Shapes of apparent mass curves were clearly different from those at erect posture especially in the frequency range around and above the second peak.

• International Journal of Automotive Technology
• /
• v.4 no.1
• /
• pp.21-30
• /
• 2003

In this paper a systematic test procedure for evaluation of road-induced noise of a vehicle and guidelines for each test are presented. Also, a practical application of the test procedure to a small SUV is presented. According to the test procedure, all the tests were performed to evaluate road-induced booming noise that is in low frequency range. First of all the information on characteristics of road-induced noise was obtained through baseline test. Coupling effects between body structure and acoustic cavity of a compartment were obtained by means of modal tests for a structure and an acoustic cavity. Local stiffness of joint areas between chassis system and car-body was determined by test for measurement of input point inertance. Noise sensitivities of body joints to operational forces were obtained through test for measurement of noise transfer functions. Operational deflection shapes made us analyze behaviors of chassis system under running condition and then find sources of noise due to resonance of the chassis system. Finally, Principal Component Analysis and Transfer Path Analysis were utilized to investigate main paths of road-induced noise. In order to evaluate road-induced booming noise exactly, all of tests mentioned above should be performed systematically.