Structural analysis of a vehicle dynamics model for fault detection and isolation on the ROboMObil

The ROboMObil, a mobility prototype under development at the DLR, differs from most current road vehicles with its high degree of overactuation with regards to the vehicle dynamics. This is due to the independent traction motor drives and steering actuators in each wheel, as well as one brake-by-wire actuator for each axle. Together with the large number of sensors, these provide opportunities for control and also lead to challenges for fault detection and isolation. In this study, the ROboMObil is represented by the dual track vehicle dynamics model. Structural analysis methods are used to determine the Minimally Structurally Overdetermined Sets of constraints. Each of these can be used to check the consistency of the constraints which it contains. A minimal set of MSO sets is selected to achieve the maximal isolation for the faults of interest. The validity of this method is illustrated using a simulation and simple analytic redundancy relations for selected MSO sets.