Migration of ADAS from Passenger Cars towards Heavy Truck and Military Applications
By Hong Bae, Ph.D. Manager, Vehicle Systems, IAV Automotive Engineering, Inc.
Advanced Driver Assistant Systems (ADAS) features currently available in the passenger car domain include Adaptive Cruise Control (ACC), Blind Spot Detection (BSD), Lane Departure Warning (LDW), Lane Change Assist (LCA), Lane Keeping Control (LKC) and Automatic Parking Assist (APA).
Manufacturers of heavy trucks (for example, class 8 tractor-trailer trucks), mass transit buses and military vehicles are also developing ADAS features. In fact, the heavy truck industry and the military have been stronger advocates of ADAS early on and funded many research projects towards the goal of automated driving.
For example, the California PATH (formerly known as Partners for Advanced Transit and Highways) had conducted research on platooning of passenger cars and heavy trucks. As one of the earliest demonstrations of autonomous driving, PATH successfully showed platooning technology. In 1997, on an expressway in San Diego, Calif., five cars were automated for speed control, lane change, and joining and splitting of platoon. Sensing technologies included radars on the vehicles and the magnetic guidance system embedded in the road.
ADAS in Heavy Trucks
The benefit of improved safety – for the driver and others on the road – from ADAS technologies is even more obvious. Outward visibility is severely limited for heavy trucks and the consequence of an accident, such as crashing into a slow moving passenger car in front, is much more severe because of the sheer size and weight of heavy trucks.
ADAS systems can help reduce the potential for accidents, making heavy duty driving safer. As a matter of fact, the upcoming Euro NCAP rating structure would make it very hard for heavy vehicle manufacturers to score good results without active safety systems such as Automated Emergency Braking (AEB).
Another example of adaptation of a passenger car ADAS feature for heavy trucks is anti-trailer skidding control. In a phenomenon known as jack-knifing, the back of the trailer may swing around under low traction situations, such as much lower weight on the trailer axle when trailer is empty. This feature is an expanded version of Electronic Stability Control (ESC) system, where traction at the trailer tires are monitored and modulated to prevent the loss of traction.
In passenger cars, a decision to purchase ADAS features is often times based on the benefit of increased safety and convenience. In the case of commercial heavy trucks, many of them are used by logistics companies and, therefore, these companies are extremely cost sensitive, especially with ever-rising fuel costs.
This sensitivity to operation cost explains why – despite the low percentage that these ADAS may represent in an overall vehicle cost – the adoption rate has been low. What many commercial heavy duty vehicle consumers do not realize is that from the cost benefit perspective, ACC and platooning can be very attractive. Studies have shown that both the lead vehicle and the following vehicles in a platoon enjoy fuel savings of 4 to5 percent and 15 percent, respectively.
When these trucks travel routinely 80,000 miles per year, the small percentage in fuel economy improvement leads to a significant operational cost savings. For this reason, research in platooning and semi-autonomous trucks has been very active in recent years.
Predictive ACC is gaining more support where the current truck location is monitored with road grade information in digital maps, and powertrain control is adjusted to maximize fuel savings, like going uphill. Cooperative ACC (CACC) is becoming a popular R&D topic that combines ACC, platooning and Vehicle to Vehicle (V2V) ideas.
ADAS in Mining Trucks
Mining trucks also are an interesting application area. Used mainly at open pit mining sites, these vehicles are gigantic in size compared to typical passenger pickup trucks. In a modern mining truck, the top of the driver’s cabin can reach over 21 feet (6.5 m) with the vehicle length up to 50 feet (15 m).
Outward visibility from the driver’s seat in the side and rear directions is virtually non-existent, and even the forward visibility can be very challenging since the driver cannot see anything right in front of the mining truck. Therefore, in addition to lane departure warning in passenger cars, road departure warning is also critical for mining trucks.
Sometimes the mining trucks have to travel a dangerously narrow road that presents more challenges due to extremely limited visibility in mining trucks. An ADAS technology that provides a clear (essentially computer enhanced) view of surroundings would prevent a mining truck falling from the edge of narrow roads that might be otherwise invisible to the operator.
A unique challenge for mining trucks is the object detection of both positive and negative objects, for example, a bicycle and a pot hole, respectively. Detection of positive objects and proper warning or active control of the vehicle, such as braking, are beneficial equally to passenger cars and mining trucks.
A negative object is essentially a vertical disappearance of ground that vehicle is currently on. Another important example of negative objects is a sudden change of road grade. A steep downward slope that is not detected by the operator of heavy trucks may lead to unintended and uncontrolled acceleration of the vehicle down the slope. In detection of both types of objects, harsh environment conditions in which mining trucks operate also present more challenges for sensing and perception, which the use of ADAS can help mitigate.
ADAS in Military Vehicles
Military has been a major force behind ADAS and autonomous driving technology, and all the benefits of ADAS for heavy and mining trucks equally apply to military vehicles. The need of reducing human causalities is, however, much greater in military operations.
The US Congress has authorized the Defense Advanced Research Projects Agency (DARPA) to award cash prizes for high risk, high pay-off robotic research that bridges the gap between fundamental discoveries and military application. The ultimate goal was to make one third of ground forces autonomous by 2015.
With two Grand Challenge and an Urban Challenge competitions, DARPA jump-started the current interest and R&D activities in autonomous cars and, today, all major automotive OEMs and Tier-1 suppliers as well as agricultural machinery makers have some form of R&D programs towards autonomous driving.
In addition to full autonomous vehicles, the military has been interested in near term technologies, such as automated convoy. Historically, many casualties occurred in non-direct combat situations where a convoy of supply vehicles is ambushed.
If automated – ether semi- or full- automated – a convoy of robotic trucks could deliver supplies from a supply depot to a battle front while minimizing human casualties. In this type of convoying, the lead vehicle can be fully autonomous (complete computer control), tele-operated (human operation at a remote location) or human-driven. The follower vehicle (or multiple follower vehicles) follows the lead vehicle either through inter-vehicle communication (communication of trajectory, relative position, etc.), on-board perception (direct measurement of relative position without communication) or some combination of both technologies.
All forms of ground transportation can take an advantage of ADAS in the passenger car industry, thanks to rapid technical advancements and lower system cost from the economies of scale. While the detailed requirements may be different, core technologies such as automotive-grade radar sensor hardware and software are easily transferred to other applications.