  Level 3+ automated driving implies highest safety demands for the entire
vehicle automation functionality. For the part of trajectory tracking,
functional redundancies among all available actuators provide an opportunity to
reduce safety requirements for single actuators. Yet, the exploitation of
functional redundancies must be well argued if employed in a safety concept as
physical limits can be reached. In this paper, we want to examine from a
trajectory tracking perspective whether such a concept can be used. For this,
we present a model predictive fault-tolerant trajectory tracking approach for
over-actuated vehicles featuring wheel individual all-wheel drive, brakes, and
steering. Applying this approach exemplarily demonstrates for a selected
reference trajectory that degradations such as missing or undesired wheel
torques as well as reduced steering dynamics can be compensated. Degradations
at the physical actuator limits lead to significant deviations from the
reference trajectory while small constant steering angles are partially
critical.
