A self-driving truck under development by Scania and KTH Royal Institute of Technology researchers has tested successfully at speeds of up to 90 kilometers per hour, safely maneuvering around obstacles on the road and carrying out tasks such as picking up and unloading gravel.

According to KTH, the tests are aimed at readying self-driving Scania trucks for mining operations within a year or two. A demonstration of the prototype, named "Astator," is scheduled for later this year in an actual mine.

Scania's self-driving truck on the test track. Image credit: Scania. "The truck drove itself with a maximum deviation of 20 centimeters from the road's center line," says Bo Wahlberg, professor of control engineering at KTH. "It performs very precisely, even at higher speeds."

KTH researchers have spent the last two years developing the truck's control algorithm so that it is as accurate and reliable as possible. Using model predictive control (MPC), the truck can drive by itself on narrow and winding roads.

"As the name implies, the model can predict the vehicle's movements in every given situation on the basis of information about what direction it's being steered in, how much throttle is given and alternatively how much braking force is applied," says KTH researcher Pedro Lima.

MPC makes it possible to minimize deviations from the intended path and maximize passenger comfort by reducing side-to-side jerks in the steering, as well as through acceleration and braking. It can also maximize the vehicle's fuel efficiency.

With greater mass and built-in inertia than passenger cars, trucks present a greater challenge for autonomous driving. Astator's control method can handle both non-linear dynamics and constraints, which is important for preventing the truck from tipping over on sharp turns.

Moreover, Astator has two steering axles. The truck's calculation model thus has to be more complex and resource-intensive. Self-driving trucks need new information every 50 milliseconds to make the right decisions about steering, accelerating and braking, Wahlberg says.