Design of an Active, Fault-tolerant Motion Control of Wheel-individual Controlled Vehicles

Four-wheel drive and four-steered electric vehicles
(4WD4WS EV) represent a passenger transportation system
using decentralized drive together with wheel individual steering
angles. Such concepts aim to satisfy future demands of urban societies,
like increasing traffic and local emission reduction. In the
present work, an active, fault-tolerant vehicle dynamics control
for a 4WD4WS EV is designed with the goal to follow a reference
velocity trajectory. The redundant, over-actuated structure of the
drive and steering actuators is used to increase the reliability of
the vehicle in order to maintain driving safety. This is done by
actively reconfiguring feedforward control together with control
allocation techniques in the event of faulty actuators. Therefore,
physically motivated failure cases based on the tire’s slip behavior
are discussed. For the considered vehicle topology, failure cases
of the actuators leading to specific effector configurations are
discussed, whereby, stable, blocked as well as inactive states of
both engines at each wheel are considered.