Final colloquium Chris van der Ploeg

21 November 2018 10:00 till 10:45 - Location: instruction room G, 3me - By: DCSC

"Fault Detection and Isolation for Lateral Control of an Autonomous Vehicle: A Model Based Approach"

This work presents a set of novel methods for fault detection and isolation for a generalized set of linear time-invariant and parameter-varying systems. The faults under investigation in this work comprise of an additive fault acting as an offset on the system and a multiplicative fault acting non-linearly on a set of known signals. Furthermore, the system is subjected to exogenous disturbances. The first challenge proposed is the lack of isolability of the additive and multiplicative fault using conventional linear estimation techniques. The second challenge proposed is the design of a fault detection mechanism for linear parameter-varying systems subject to exogenous faults and disturbances.

The first contribution of this research provides a moving least-squares based approach as an extension to an existing nullspace computation based parity-space fault detection filter. Use of this novel combination allow a decoupled estimation of the additive and multiplicative fault. The second contribution of this thesis work provides an extension to the first contribution by attacking one of the largest sources of error, the dynamical content of the parity-space filter. The estimation performance of the combined fault detection and isolation filter of both contributions is provided with a guaranteed performance bound, providing not only an intuitive tool to push down the estimation error but also shows possible trajectories for future work. The third and final theoretical contribution of this thesis work adapts the linear time-invariant parity space method for a linear parameter-varying environment. A convex quadratic optimization problem is used which has an exact analytical solution for approximately rejecting the parameter-varying effects of the system.

Implementation of the theoretical framework is shown in a practical case study in fault detection and isolation for lateral control of autonomous vehicles. In this application there is a particular interest in detecting and isolating the additive and multiplicative fault for compensation or decision making of the autonomous system in faulty scenarios. After having proven out the theoretical framework in a linearized simulation environment, the final contribution shows the systematic approach of applying the contributions in an experimental setting on an autonomous vehicle in a low excitation scenario. The experimental results confirm the theorems, showing that the faults can be detected and isolated in theory and in practice. 

Dr. M. Alirezaei