On-board electric powertrain control for the compensation of the longitudinal acceleration oscillations caused by road irregularities

Road irregularities affect vehicle comfort by causing vertical and longitudinal acceleration oscillations. While the current ride comfort enhancement solutions are based on the compensation
of the vertical acceleration of the sprung mass, the compensation of the longitudinal dynamics
excited by road irregularities has been successfully explored only for in-wheel powertrains. The
scope of this study is to demonstrate that also on-board electric powertrains with torsional dynamics of the half-shafts have the potential for effective compensation, thanks to the road profile
preview. This paper presents a proof-of-concept nonlinear model predictive controller (NMPC)
with road preview, which is assessed with a validated simulation model of an all-wheel drive
electric vehicle. Three powertrain layouts are considered, with four in-wheel, four on-board, and
two on-board electric machines. The control function is evaluated along multiple manoeuvres,
through comfort-related key performance indicators (KPIs) that, for the four on-board layout
along a road step test at 40 km/h, highlight >80% improvements. Finally, the real-time implementability of the algorithms is demonstrated, and preliminary experiments are conducted on an
electric quadricycle prototype, with more than halved oscillations of the relevant variables.