Audi details piloted driving technology

Before autonomous vehicles make drivers obsolete, electronic technologies will depend on people to make decisions when something unusual happens. During normal driving conditions, autonomous controls could pilot the vehicle, relying on humans when complex decisions are required.

Audi recently provided technical insight into its piloted vehicle project, in which an Audi A7 concept car drove from San Francisco to Las Vegas earlier this year. The vehicle drove itself most of the journey, though drivers had to remain alert to take over when alerts directed them to resume driving.

The concept car has a range of computers in the trunk. Audi engineers plan to reduce them to a single board over time. The mainstays of the piloted vehicle technologies are an array of cameras, radar, and ultrasonic sensors that are controlled by what’s called the zFAS board. It combines sensor inputs to give the car its view of the world.

“All raw signals from the sensors is collected in a sensor fusion box,” Matthias Rudolph, Head of Architecture Driver Assistance Systems at Audi AG said during the recent Nvidia GPU Technology Conference. “From that input, a virtual environment is created.”

Four semiconductors are the basis of the zFAS board. An Nvidia k1 processor collects data from four cameras and “does everything while driving at low speeds,” Rudolph said. An Infineon Aurix processor handles additional chores. Mobileye’s EyeQ3 performs vision processing, while an Altera Cyclone FPGA (field programmable gate array) performs sensor fusion.

The software architecture is layered, with the perception sensor programs forming the first layer. Above that, there’s a fusion layer that blends data from the sensors with information from maps, road graphs, and other sources. Rudolph noted that combining inputs provides better information and increases confidence in the analysis.

“Radar is not good at determining the width of a car,” Rudolph said. “A camera does that well. If we fuse data from each of them we get good information on what’s ahead.”

Ensuring that the zFAS boards detect potential threats and respond to them correctly without false alerts is critical. If vehicles stop or swerve to avoid something that isn’t a true danger, drivers are likely to stop using the system.

“If the car brakes and nothing’s there, it will destroy the confidence of the driver,” Rudolph said. “We have had no false positives; that’s been proven with over 10,000 hours of driving at an average speed of 60 kph (37 mph) in situations including snow and freezing rain.”

Audi looks at moving objects to analyze their potential impact given the vehicle’s driving path and speed. All stationary items are viewed with a single goal.

“We look at static images as the same,” Rudolph said. “It doesn’t matter if it’s a wall or a parked car, we don’t want to hit it.”

Pedestrians are a major challenge for all types of autonomous systems. They’re harder to spot and categorize than vehicles, and they have more degrees of freedom. The system uses a single monocular camera to search for pedestrians. Given the erratic behavior of some walkers, Audi doesn’t stop for pedestrians unless they’re truly in harm’s way.

“When we detect pedestrians, we compute the time to contact,” Rudolph said. “We’re close when the vehicle stops. We want to be close, just a few centimeters away. We do not want to stop far away.”

Though the piloted system aims to avoid pedestrians and most everything else, Audi realizes that collisions can’t always be prevented.

“If we can’t avoid an accident, we steer to use the structure of the car to minimize the chance of injury,” Rudolph said.

Such an action would occur mainly when the human driver didn’t take over in time to avoid a collision. Audi uses an LED alert system to tell drivers when they need to take charge. They can do that by hitting the brakes or making a sharp steering wheel movement. An internal-looking camera watches drivers so the system knows whether the LED alert needs to be augmented with an audible warning.

“In the piloted driving mode, we may need to get the driver back, so we need to know what he’s doing,” Rudolph said.

Schaeffler developing novel powertrain for 2015/2016 FIA Formula E season

“We are in the process of developing an electric motor and a new transmission in the defined specification that FIA came up with,” said Prof. Dr.-Ing. Peter Gutzmer, Deputy CEO and Chief Technology Officer for Schaeffler AG.

Gutzmer and Schaeffler’s CTO for the Americas, Jeff Hemphill, sat down with Automotive Engineering prior to Formula E’s March 14 street race in Miami, the first U.S. stop in the 2014/2015 inaugural season of all-electric racing in Europe, Asia, and the Americas.

As Team ABT Sportsline’s exclusive technology partner, Schaeffler is developing a novel power unit to replace the McLaren Applied Technologies powertrain. “We are now starting to get parts in for the prototype model,” said Gutzmer.

Schaeffler technical specialists are leveraging their extensive application development know-how together with the ABT race team and other technology experts to develop jointly a powertrain for Team ABT Sportsline. Said Hemphill, “One of our strengths in the automotive arena is systems engineering, and we’ll apply that systems approach to this development task.”

Each Formula E racecar in the 2014/2015 season uses a 57-lb (26-kg) motor to accelerate the single-seat car from 0 to 62 mph (100 km/h) in 3 seconds. The motor mates to a Hewland Engineering five-speed paddle shift sequential gearbox.

Audi Sport ABT driver Daniel Abt told Automotive Engineering that the electric racecar’s instant torque means “whenever you hit the throttle, it just goes. There is no delay. And there’s a lot less noise than if you had a screaming V8 engine behind your back.”

Virtually no technical details about the under-development powertrain are being publicized. “I hesitate to talk too much. There are seven competitors producing electric motors for next season, so it’s getting very interesting,” said Gutzmer.

Jacky Eeckelaert said the next race season is all about increasing the powertrain efficiency. “And the whole package will be lighter and at a lower center of gravity,” Eeckelaert, race engineer for ABT team driver Lucas Di Grassi, told Automotive Engineering.

While Schaeffler has supplied bearing components and alternator overrun systems for baja, endurance, and touring series cars powered by internal-combustion engines, developing an electric racecar powertrain is new territory. Said Gutzmer, “This is the first time that Schaeffler will be providing a functional, complete unit.”

One desirable for the Schaeffler powertrain is improved cooling efficiency.

Team owner Hans-Jurgen Abt spoke with Automotive Engineering while a crew member put dry ice inside the air intake ports for the battery cooling system and the engine cooling system.

“The dry ice can lower the temperature about 25°C. We need to pull the temperature down because then you can increase the power. In the race you have only the cooling from the air, and it doesn’t help if you have not the right temperature to start,” Abt said prior to the 39-lap, 1.34-mi (2.16-km) Miami race.

Developing an electric powertrain for a racing application will mean challenges and victories.

“You have to work with suppliers on different materials; that’s a challenge. You have to have a very fast loop of re-engineering if re-engineering is necessary,” Gutzmer said, referencing some of the challenges. “But the knowledge that we gain during this process will be fruitful for future developments.”