Self-Driving Trucks Could Alleviate Supply Chain Problems

“Automated driving features offered by many OEMs are at Level 2 or Level 2+,” Malleichervu says, where the plus designates increased autonomy without quite reaching Level 3. “With these levels, the advanced driver assistance system (ADAS) on the vehicle controls the braking system, accelerating, and steering, with the human driver still responsible for monitoring the environment at all times and performing all other driving tasks.”

This relatively limited level of autonomy is due in part to the safety concerns inherent in testing and developing ADAS for vehicles in urban environments.

This is where TuSimple’s trucks have an advantage, Han says. While the company doesn’t expect its trucks to be out on the road in full force until at least 2024, testing this technology on less densely driven highways instead of city centers offers an easier path toward achieving full autonomy. To test autonomous vehicles in a city, companies must first come to agreements with local authorities on where, how often, and at what speeds their vehicles can be tested. This often means reducing the area and time available for testing.

Another bonus for highway testing is that it faces fewer pedestrian obstacles than in cities and largely avoids stop-and-go traffic and narrow or uneven roads. While this doesn’t completely remove the risk of harm to other drivers should something go wrong, it does lessen the likelihood of a deadly accident.

Right now, Han says that TuSimple’s trucks are at Level 4 autonomy. This means that the vehicles can drive themselves under limited conditions without the assistance of a human driver—although in TuSimple’s case the company plans to still have human drivers supervise from the driver’s seat. Unlike trucking today, which requires constant vigilance from human drivers, Level 4 or 5 autonomous trucks would give them an opportunity to rest while driving through the night on empty roads.

A crucial aspect of this autonomy that Han and his team have been developing is an autonomous by-wire braking system. The weight of the big rigs, along with the dynamics associated with pulling a fully loaded trailer, makes it harder for them to quickly stop. A fully loaded truck can weigh as much as 36,000 kg (80,000 pounds), whereas a passenger car weighs closer to 1,360 kg (3,000 pounds). The braking system must be able to safely stop the momentum of a heavy truck traveling at highway speeds.

“The by-wire braking system is very complex,” says Han. “The whole pipeline starts from perception, where our program looks at its surroundings in the front and back of the vehicle. This includes motion planning, prediction, and the control algorithm.”

Using perception and sensors such as lidar, TuSimple’s L4 autonomous system sees 360 degrees around the vehicle and 1,000 meters in front of it. The data is then passed along to the safety-critical brake-by-wire control system, Han explains, which then makes the connection between software perceptions to the truck’s hardware to activate safe braking.

“Braking is the most fundamental system in autonomous driving,” says Han. “The safety level for braking is above all the other systems.”

These stricter standards for the braking system are also reflected in its redundancies, Han explains, which allow human controllers to intervene and brake manually if something goes wrong.

“For other parts of the vehicle, such as the engine, a certain level of redundancy will suffice,” Han says. “However, because braking systems are the most safety-critical part of the vehicle, we must have full redundancy including the physical, signal, power, and software systems.”