Although transport truck drivers routinely shift gears when going up or down hills, those hills can sometimes sneak up on them. Using Daimler’s GPS-enabled Predictive Power Control, however, the new Mercedes-Benz Actros tractor unit will now be able to see those hills coming. This will allow it to automatically change gears before the going gets tough, resulting in fuel savings of up to three percent over moderately difficult topography.
In 2009, Daimler introduced a system known as Predictive Cruise Control, on its Freightliner trucks in the U.S. This uses GPS data to control the vehicle’s speed and braking functions for maximum efficiency, given its present geographical location. Predictive Power Control is built on this system, but uses its knowledge of the road ahead to also preemptively downshift the Actros by one or two gears.
According to Daimler, the system’s performance “could only be matched by an extremely motivated truck driver with an exceptional level of concentration.”
Self-driving vehicles will really be able to take advantage of every technique to save fuel, and freight vehicles IMO are actually a great first candidate for such autodriving systems, as they'd benefit the most from the positional data from sensors and fuel savings. Can't wait for the future to be here.
Have to remember that as these vehicles are running up against their speed limiter all the time (on flats and declines), accelerating on the declines is illegal, (not possible if the speed limiter is working as designed), dangerous and not particularly energy efficient. Recovering and reusing the energy from the declines on the inclines is a much more efficient method...
All cruise controllers should have accelerometers in them, to respond as the incline increases (before the speed begins to drop. ie. deceleration), and then reduce throttle response as the incline rolls off, which would reduce oscillations and over speed conditions when driving in undulating conditions on cruise control.
(Sure we could use MPC on all systems, but it is simpler (and more understandable for many techs) to retain a nested PID control regime in many simple systems... Sure, additional loops introduces non-linearities in the controller but as they will most likely be stable, who cares.)
MPC is more possible on frequently driven roads, if the database is automatically updated for road conditions. Though a small, offline sensor suite can also provide a limited horizon for predictive modelling to improve outcomes.