Truck & Off-Highway Engineering - August 2018 - 8

TECHNICAL INNOVATIONS

OPERATOR COMFORT

Link readies semi-active cab suspension
for intro on select 2020 models

vehicles can talk to each other.
"In a mixed environment where sometimes this information
might be available, sometimes not, it can become a source of
potentially useful information, but if it is unreliable you may
not want to base safety decisions on this data source,"
Williams said.
The National Traffic Highway Safety Administration's
(NHTSA) tardiness in mandating a rollout date has created
questions around adoption. Cellular promoters say that 5G
connections provide enough bandwidth to provide many of
the benefits.
Called C-V2V, it is gaining some interest from automakers
who feel they can eliminate the cost of a DSRC link by using
cellular modems that are likely to be on most cars in a few
years. Given the lack of usage in cars and trucks, some groups
have discussed selling some of the 5.9-GHz DSRC spectrum.
That's not palatable for most DSRC proponents.
"We're working with the FCC to protect our wireless spectrum," Brandis said. "If we get narrower bandwidth, it will restrict the amount of data we can send. That's important for
the future, when even more data will be sent."
Having a communications infrastructure capable of handling lots of data is viewed as an important element in the
drive to automate all driving. Data on road and weather conditions can help autonomous vehicles navigate safely.
Vehicles could also share information about pedestrians near
roadways, as well as providing real-time traffic info. V2V input
is often viewed as sensor information that extends farther
than on-board sensors. Increasing the volume and confidence
levels of environmental data will be important as autonomous
trucks move from limited applications to mainstream driving.
"Further out, we will use more sensing to identify safety
issues all around the vehicle, and combine longitudinal and
lateral control," Williams said. "These associated functions
will help to improve safety and efficiency of commercial vehicles, and lead to increasing levels of automation. The first
automated vehicles will appear in duty cycles that are relatively easy to navigate, such as hauling from a mine pit to a
railhead on a remote road, or maintaining a lane on a limited
access highway."
Terry Costlow

8 August 2018

In-house-developed system

The project team determined that most of the system's development could be accomplished in-house. Link created its own
control system, writing proprietary algorithms to govern system performance. The team continues to work with its shock
absorber suppliers to perfect dampers that will be exclusive to
the semi-active Cabmate application. Both magnetorheological
(MR) dampers and hydraulic actuation are being explored.

Shock absorbers using magnetorheological technology employ voltage
from the Cabmate's ECU causing fluid in the shock to quickly become
more or less viscous, making the shock stiffer or softer as needed.
TRUCK & OFF-HIGHWAY ENGINEERING

FROM TOP: VOLVO TRUCKS; LINK MANUFACTURING

Platooning brings many benefits, but regulations for certifying V2V
remain elusive.

Link Manufacturing targets heavy-duty vehicles that transition from on- to off-road terrain, in particular, for what it
claims will be the industry's first intelligent semi-active cab
suspension. The benefits of such a system are many, according to the company's VP of Engineering, Bill Ott. Chief among
them is an improved work environment for operators, which
could ultimately help with driver retention, he said.
Less stress on the cab, its structure and the driver also
means lower maintenance costs, better vehicle handling and
reduced driver fatigue, which could result in increased productivity. For these reasons-and the not-insignificant matter
of reasonable cost-Ott believes the time has finally come for
market acceptance of this technology.
"Not surprisingly, it will cost more than our traditional
Cabmate due to the added components and complexity. The
level of integration into the OEM electronics will also have a large
impact on the final cost. When all the dust settles, I believe our
system will be less than the cost of installing two premium seats
in a sleeper cab," he told Truck & Off-Highway Engineering.
Link began exploring semi-active cab suspensions prior to
2006 but shelved the project because the technology was costprohibitive. The company's engineering team revisited the idea
in 2014. "Our skunkworks team started by determining that we
could simplify the dampers and control systems for a cab suspension because the cab suspension is itself suspended by a
primary system," Ott said. "We're taking this into account to reduce the cost and complexity of our semi-active Cabmate."

Truck & Off-Highway Engineering - August 2018

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