about a tutorial on the GM adaptive cruise control system?
Specifically, I’m curious as to whether the GM system uses engine
or mechanical braking, or combinations thereof, in decelerating
vehicles when encountering slower traffic. When decelerating, the
brake lights are not activated. Doesn’t this pose a hazard to
understand other manufacturers use a laser system rather than
millimeter-wave radar. Are other technologies involved? I have a
2008 Cadillac DTS and love it.
come a long way from the first cruise control system found on the
’58 Chrysler. Conventional cruise control systems use throttle
only to try to balance operator-desired speed versus actual vehicle
speed. On downgrades, vehicle speed may overrun the desired set
cruise control can have many names and is typically found on luxury
vehicles, because of its fairly high cost. It is trickling down and
may become standard equipment on all vehicles, given time. Adaptive
cruise control, or ACC, uses radar, LIDAR (laser) and/or cameras to
perceive vehicles ahead and their behavior. Should you come upon a
slower-moving vehicle with ACC engaged, engine throttle is reduced
and, if need be, brakes are applied to maintain your desired
following distance. Brake lights are deployed when your deceleration
rate reaches a calculated threshold.
ACC employs a
complex network of vehicle modules to manage things smoothly. Your
Caddy uses a distance-sensing cruise control module, located behind
the grille, to ping the roadway ahead and classify objects. A yaw
sensor tells the system if you are traveling straight or turning.
Brake and accelerator pedal sensors also indicate possible override
input, and your selection of desired following distance is also
considered. Participating modules include the engine control module,
transmission control module, electronic brake control module,
instrument panel module and even the radio amplifier. The system is
smart enough to predict brake temperature and downshift the
transmission as needed for engine holdback. And should the radio
amplifier not work, ACC will stand down, since audible warnings
wouldn’t be available.
systems are the most popular by a wide margin. In some cases,
cameras provide additional object classification, coupled with GPS
to determine road and intersection characteristics. These
super-smart systems can predict the car ahead with a flashing turn
signal will probably turn off at the exit — yikes!
mitigation is a logical spinoff of ACC capabilities and is available
on many systems. Even with cruise control disengaged, these systems
will detect threats ahead and warn you, disengage throttle, and
apply brakes as needed to avoid a collision. Let’s hope folks don’t
become complacent and expect the car to keep them safe in every
circumstance. No system can be expected to function perfectly every
In the future,
we’ll move from autonomous to cooperative systems, where vehicles
will communicate with each other. This will allow tightening of
following distances and less reactive stop-and-go maneuvering,
speeding traffic along more smoothly.