Hyundai Motor Group develops first road noise active noise control technology; to be applied to Genesis model

Hyundai Motor Group has
developed
the first Road Noise Active Noise Control (RANC)
system. RANC builds on the Group’s current Active Noise Control
(ANC) technology, which actively reduces noise by emitting
soundwaves inverted to incoming noise.


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ANC is a software-driven technology that analyzes the in-cabin
sound to decrease engine and road noise, rather than the passive
method of blocking noise through sound insulation.

The passive noise insulation method involves sound insulations
and dynamic dampers which not only increase weight but also fail to
block the buzzing infrasound completely. In contrast, ANC utilizes
much lighter components such as microphones and controllers to
control the noise and reduces infrasound more efficiently. The
technology is already available in some Hyundai Motor Group
vehicles.

However, due to the limitations of noise measurement and
analysis technology, the existing ANC was only able to be utilized
when noise was constant and the occurrence of the noise
predictable. The Group’s current ANC technology has been most
commonly used to counteract constant engine noise. Given that it
only takes about 0.009 second for road or engine noise to reach the
passenger, the current technology was limited.

With the RANC technology, Hyundai Motor Group is able to improve
in-cabin quietness. The new system can analyze various types of
noise in real-time and produce inverted soundwaves. For example,
there are different types of road noises that the new technology
can process, such as resonant sounds created between tires and
wheels or rumble sounds coming up from the road.

The working principle of RANC is as follows: Using an
acceleration sensor, RANC calculates the vibration from the road to
the car and the control computer analyzes road noise. As its
computation and signal transfer speeds are optimized, it only takes
0.002 second to analyze the noise and produce an inverted
soundwave, generated by the DSP (Digital Signal Processor).

The microphone constantly monitors the road noise cancelation
status, and sends the information to the DSP. RANC is able to
conduct accurate noise analysis and rapid computation to combat
road noise for the driver’s seat, the passenger seat and rear seats
separately.

Based on tests evaluating road surface, vehicle speed, and
different seating positions, RANC was able to reduce in-cabin noise
by 3dB. That 3dB level is roughly half the noise level as compared
without RANC. Thanks to this achievement, the Group can potentially
decrease the amount of unsprung weight in a vehicle, utilizing
fewer sound-insulating parts and dampers as compared with
before.

Hyundai Motor Group went through six years of research and
development for the mass production of RANC. Especially, the
pre-production phase involved an open innovation between industry
and academia, with participation by Korea Advanced Institute of
Science and Technology, WeAcom, ARE, BurnYoung and more.
Furthermore, the mass production phase was carried out with global
car audio company Harman to increase degree of competition.


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Hyundai Motor Group has completed domestic and US patent
application about the location of sensors and signal selection
method, the core technology of RANC.

Looking to the future, in-cabin quietness will become more
important as internal combustion vehicles are phased out. Vehicle
interior noise primarily comes from three sources: vehicle
powertrain noise, road noise, and wind noise. There is almost no
powertrain noise from electric and fuel cell electric vehicles, so
quelling road and wind noise becomes even more imperative.
Utilizing RANC can significantly reduce road noise and create a
serene cabin for future electric and fuel cell electric
vehicles.

The technology will begin to be applied to an upcoming Genesis
model.

Source: FS – Transport 2
Hyundai Motor Group develops first road noise active noise control technology; to be applied to Genesis model



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