Self-driving mining truck stable at 90 km/h

According to the research lead at KTH Royal Institute of Technology, the successful tests are aimed at implementing self-driving Scania trucks in mining operations within a year or two.

"We have come a long way with the work and have already proven with a real truck that the task is possible," says Bo Wahlberg, professor of control engineering at KTH.

"The truck drove itself with a maximum deviation of 20 centimeters from the road's center line," Wahlberg says. "It performs very precisely, even at higher speeds."

One of the KTH researchers involved in the project, Pedro Lima, says the prototype, named Astator, traveled "softly and stably" at its maximum speed of 90 km/h.

KTH, Scania, Linköping University, Saab and Autoliv and collaborating in a government-funded project called iQMatic, which is aimed at to develop a fully self-driving truck for difficult environments such as mines.

The next big demonstration of the Scania truck is in May. A demonstration in a real mine is scheduled for the late autumn, Wahlberg says.

The concept has developed to the point where the truck can safely handle obstacles on the road and carry out tasks such as picking up and unloading gravel.

Several researchers from KTH are participating in the project, including Lima and Wahlberg, who together with Jonas Mårtensson 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," Lima says.

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 consumption.

He adds that the control method can handle both non-linear dynamics and constraints, which is important for preventing the truck from tipping over on sharp turns.

With greater mass and built-in inertia than passenger cars, trucks present a greater challenge for autonomous driving.

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 the steering, accelerator or brakes, Wahlberg says.