Automotive Engineering - April 2024 - 23

AUTOMATED DRIVING FEATURE
Full speed ahead for
second-generation Indy
autonomous racers
Major hardware and
software upgrades underpin
the Indy Autonomous Challenge
racecar for 2024, proving self-driving
vehicle capabilities at triple-digit speeds.
by Kami Buchholz
A
fter three years and more than 7,000 miles (11,265 km) of
racing, the Indy Autonomous Challenge (IAC) enters year
four with an updated platform and embedded software upgrades.
Among the highlights for the second-generation
open-wheel racecars are pending patents and first-time applications.
" We've achieved several impressive milestones since our start in
2020, " IAC President Paul Mitchell said.
The achievement list includes setting a speed record for passing in
autonomous racing (170 mph [273 km/h]), netting the autonomous
vehicle land speed record (192.2 mph [309.3 km/h]) and establishing
the fastest lap speed for an autonomous vehicle (180 mph [289.68
km/h]). " More than anything, we consider the IAC an applied-research
platform for industry and academia to work together on advancing
high-speed autonomy, " Mitchell said.
Eighteen universities from around the world are participating in
IAC 2024 events. This year's line-up features nine teams, with each
group made up of between one and four universities. Each team's
IAC-supplied racecar - fitted with sensors, GPS technology and a
central computer - operates on custom-designed instructions. " It's a
software challenge for teams, " Mitchell said. " They're competing on
the development of the AI driver, also referred to as the autonomous
software stack. Each team decides when to steer, when to brake and
what the throttle position should be. "
Each team uses the same hardware, but there is some optionality
about the wing position and the amount of downforce, Mitchell said.
IAC and partner companies install and service the cars' chassis and
company-specific components.
New platform, newer sensors
IAC's 2024 platform (IAC AV-24) dramatically differs from the original
2021 platform (IAC AV-21) via upgraded components. " The quality
of LiDAR and radar technology and onboard computing has just gotten
better because the industry is moving that fast, " Mitchell said.
" So [IAC AV-21] components were changed out, not because the
components weren't working right or weren't effective, but because
something new is available. "
AUTOMOTIVE ENGINEERING
The secondgeneration
IAC
racecar is referred
to as the IAC AV-24.
A patent-pending, custom-engineered drive-by-wire
system on the IAC AV-24 replaced off-the-shelf steerby-wire
and brake-by-wire systems, for example. The
new steer-by-wire system in AV-24 uses a high-power
motor that enables quicker steering speed, which improves
vehicle handling. IAC AV-24's brake-by-wire uses
linear actuators compared to the earlier system's servo
motors. Independently actuated front and rear master
brake cylinders are equipped with high-resolution
brake-pressure sensors. The linear actuators include a
position sensor capable of reading the absolute linear
position with a high resolution of up to two microns. " A
separate linear actuator is used for both the front and
rear braking system, allowing autonomous dynamic
brake bias and migration, " Janam Sanghavi, head of
engineering and vehicle integration for IAC, said.
The new actuating units for braking and steering, as
well as a fully upgraded sensor kit, enable new software
programming opportunities, according to Rodrigo
Senofieni, control engineer with the PoliMOVE-MSU
Autonomous Racing team comprised of Politecnico di
Milano in Italy and two U.S. schools, the University of
Alabama and Michigan State University. The new automated
race control system, " allows us to push even more
from our autonomous software stack, thanks to better
sensor specs and faster actuating units, " Senofieni said.
IAC AV-24 has the world's first autonomous vehicle
application of 360-degree long range lidar via four
Luminar Iris sensors. The IAC AV-21 used Luminar's
H3 sensors with a field of view up to 150 m (492 ft).
" These [new Luminar Iris] sensors offer a field of
view that extends up to 250 m (820 ft), allowing for
early detection of vehicles, " Riccardo Poli, PoliMOVEMSU's
perception engineer, said. Three long-range
lidar sensors are mounted in the cockpit to provide
April 2024 23
IAC
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