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.

April 1, 2024

Kami Buchholz

The TUM Autonomous Motorsports team from the Technical University of Munich (Germany) won the 2024 autonomous challenge at CES. The racecar reached a maximum speed of more than 150 mph (241 km/h). (IAC)

After 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 second-generation IAC racecar is referred to as the IAC AV-24. (IAC)

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.

“Testing and proving out systems at high speeds opens up the potential for use cases that may still be a decade or more from happening, but will eventually be part of our mobility ecosystem” – Paul Mitchell, IAC. (IAC)

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.”

In a first for high-speed autonomous racing, the KAIST (Korea Advanced Institute of Science & Technology) car and the TUM Autonomous Motorsport car raced side-by-side, two wide, and wheel-to-wheel through turns one and two, getting as close as 1500 mm (4.9 ft) from each other during the 2024 IAC event at CES. (IAC)

A patent-pending, custom-engineered drive-by-wire system on the IAC AV-24 replaced off-the-shelf steer-by-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 modular design of the IAC AV-24’s robotics system is crucial for allowing interchangeability and integration across different vehicle platforms.” – Janam Sanghavi, IAC. (IAC)

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, PoliMOVE-MSU’s perception engineer, said. Three long-range lidar sensors are mounted in the cockpit to provide front and side views, and a fourth faces rearward from near the rear wing.

Integration of long-range lidar on the racecar posed several engineering challenges, including the issue of reduced point density. To overcome the various challenges, a perception module was developed. “This custom module effectively harnesses and consolidates all the available information from the sensor, ensuring an optimized utilization of the long-range lidar data,” Poli said, noting the tailored solution enables precise and reliable vehicle-detection capabilities that address the demands of a racing environment. In addition to the lidar, the IAC AV-24 is equipped with two radar sensors supplied by Continental – positioned front and rear – as well as multiple cameras. “The sensor suite ensures a robust and versatile perception system for the racecar,” Poli said.

The racers’ patent-pending modular robotics system allows for interchangeability and integration across different low-speed or high-speed vehicle platforms. “This approach — an adaptive robotics stack with agnostic design — not only facilitates extensive testing, but it also enhances software robustness and paves the way for the development of mass-market driverless products,” IAC’s Sanghavi said. The modularity of IAC AV-24’s robotics system also benefits maintenance, component/system swapping and upgrading tasks.

Hands-off after green

Once an autonomous race starts, teams basically become spectators. “We can only send safety-related commands from the pit-lane if we see any kind of problem from the live telemetry,” PoliMOVE-MSU’s Senofieni said. Specific commands, to follow a certain speed or switch between multiple trajectories, for example, are sent to the vehicle during practice and test sessions, according to Senofieni.

Teams have been using team-developed or commercial partner simulation tools since 2021, but the ability to compete against other teams in a simulated environment has been limited because not all teams have been using the same tools. “Over the next few months, we’re rolling out dSPACE software-in-the-loop simulation to teams, which will allow AI driver training as well as head-to-head racing,” Mitchell said.

IAC’s 2024 competition year began with an event during January’s Consumer Electronics Show (CES) in Las Vegas, Nevada. Other events scheduled this year will take place in the UK – a hill climb during the Festival of Speed at Goodwood in July – in the U.S. at the Indianapolis Motor Speedway in September, and in Europe at the F1 circuit in Milan, Italy, on a yet-to-be-determined date.