Development of a High-Resolution Measurement System of Rotating Tires towards Noise Prediction
Invited paper
Virginia Tech
Wednesday 3 june, 2015, 09:20 - 09:40
0.2 Berlin (90)
Abstract:
This paper presents a high-resolution measurement system of rotating tires
towards noise prediction. The developed system, to be mounted on a tire
testing machine, consists of digital cameras, strobes, a field-programmable
gate array (FPGA) board and a high-resolution encoder. The developed system
captures a clear instant image of a rotating tire irrespective of the
rotation
speed by triggering strobes with a significantly short duration. The use of
the high-resolution encoder together with the FPGA allows the system to take
an image in the order of 0.0001<sup>&_circe;</sup> resolution. Since the
rotation of a
tire on a testing machine is periodic, the system can effectively capture
the
deformation of a rotating tire at a high sampling frequency though the
digital
cameras used may not have a high frame rate. The digital cameras proposed
in
the system are commercially available digital single-lens reflex (DSLR)
cameras, which are CMOS-based and thus have high resolution, equipped with
macro lenses, which further improve resolution by zooming into the tire
deformation. This low-cost system is, therefore, considerably superior to
high-speed cameras in both frame rate and resolution and could measure tire
deformation associated with sound generation by synchronously measuring
sound
with a microphone array.
The validity of the developed system was preliminarily investigated by
rotating a tire at the speed of 120 km/h and capturing images at every
0.025<sup>&_circe;</sup> rotation. The result has validated the system by
capturing tire
deformation in clear high-resolution images. The sound measurement by the
microphone array has then shows its variation in response to the different
tire deformation.