Investigating Functional Redundancies in the Context of Vehicle Automation - A Trajectory Tracking Perspective
This work addresses safety requirements for Level 3+ automated driving by exploring actuator redundancy, but the findings are incremental and limited to a single reference trajectory.
The paper investigates whether functional redundancies among vehicle actuators can compensate for degradations in trajectory tracking for automated driving. Results show that degradations like missing wheel torques or reduced steering dynamics can be compensated, but physical limits cause significant deviations.
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.