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Vibration measurement in rear view mirror: an approach in relation to the driving visual quality
2002 (English)Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
Abstract [en]

Vibrational behaviour on the rearview mirror surface of truck is one of the critical targets in evaluating the quality of the mirror, which has high influence on visual quality of the rear view field. The vibration on the mirror is induced by tyre/road interaction, engine, gearbox/powertrain, and airflow surrounding mirror body. However it is unknown how much the influence from wind load is. Meanwhile, when consider the visual quality of rearview mirror, the most significant parameter is the angular displacements, especially in low frequency domain. If an angle of the mirror is rotated, the image of the object that a driver sees from the mirror is double rotated, i.e.,. If the angular displacements are beyond the standard, the driver may perceive the wrong information from the mirror which can lead the dangerous judgments. Moreover, the driver may feel the visual fatigue if the vibrational displacements are intensive on the mirror or if he/she drives in the vibration environment for long time. This project is focused on finding out the vibration behaviours induced by wind and engine inputs, and how it affects on the visual quality. Measurements are performed at engine idle sweep in Volvo Lundby Work Shop (Gothenburg), and field tests in Volvo Proving Ground (Hällered), to find out vibration behaviours. The angular accelerations and of the rigid mirror glass are measured. The angular displacements are obtained by using commercial analyzer in the post-process. The results indicate that the most serious mirror vibration in the field test is yaw displacement (z) in low frequency domain. This vibration is mainly induced by high engine revolution (beyond 1000 rpm). The max. yaw displacement can reach a value 47 times as high as the target, and max. pitch displacement can reach a value 5 times as high as target. It is found that this short test (40 to 70 sec. in each direction) is very sensitive. A small difference among the repeated tests can cause high changes. The max. increments for repeating the test can reach over 600%. Driving with and without trailer weight does not contribute much to change the mirror vibration compared with the test reproducibility. Wind effect is not so clear from the test due to low reproducibility.

Place, publisher, year, edition, pages
2002.
Keyword [en]
Technology, rear view mirrors, trucks, vibration
Keyword [sv]
Teknik
Identifiers
URN: urn:nbn:se:ltu:diva-55761ISRN: LTU-EX--02/278--SELocal ID: c96d9d6a-2f12-44fc-be46-2b24735ce68bOAI: oai:DiVA.org:ltu-55761DiVA: diva2:1029145
Subject / course
Student thesis, at least 15 credits
Educational program
Ergonomics, master's level
Examiners
Note
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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