On Pre-Emptive In-Wheel Motor Control for Reducing the Longitudinal Acceleration Oscillations Caused by Road Irregularities

Road irregularities induce vertical and longitudinal vibrations of the sprung and unsprung masses, which affect vehicle comfort. While the vertical dynamics and related compensation techniques are extensively covered by the suspension control literature, the longitudinal dynamics on uneven road surfaces are less frequently addressed, and are significantly influenced by the tires and suspension systems. The relatively slow response of internal combustion engines does not allow any form of active compensation of the effect of road irregularities. However, in-wheel electric powertrains, in conjunction with pre-emptive control based on the information on the road profile ahead, have some potential for effective compensation, which, however, has not been explored yet. This paper presents a proof-of-concept nonlinear model predictive control (NMPC) implementation based on road preview, which is preliminarily assessed with a simulation model of an all-wheel drive electric vehicle with in-wheel motors, including a realistic tire model for ride comfort simulation. The major improvement brought by the proposed road preview controller is evaluated through objective performance indicators along multiple maneuvers, and is confirmed by the comparison with two benchmarking feedback controllers from the literature.

Automated summary

Road irregularities can cause both vertical and longitudinal vibrations in a vehicle, impacting ride comfort. While vertical dynamics have been extensively studied, longitudinal dynamics on uneven roads have received less attention. The relatively slow response of internal combustion engines limits their ability to compensate for road irregularities. However, by utilizing in-wheel electric powertrains and pre-emptive control based on road profile information, potential solutions for effective compensation can be explored. This paper introduces a proof-of-concept nonlinear model predictive control (NMPC) implementation based on road preview, and evaluates its performance using a simulation model of an all-wheel drive electric vehicle. The results show significant improvements in ride comfort, as compared to benchmarking feedback controllers.