Dissertation Defense: Fault Estimation and Fault-Tolerant Control for In-Wheel Motor Electric Vehicles

Committee Members

• Professor Junmin Wang, Chair (Mechanical Engineering)
• Professor Ahmet Kahraman (Mechanical Engineering)
• Professor Chia-Hsiang Menq (Mechanical Engineering)

Abstract

With the fast development of batteries, sensors, and electric motors in the past decade, the ground vehicles are increasingly electrified. With more sensors and actuators being equipped, they may suffer from increased possibility of sensor and actuator faults. This dissertation therefore addresses the fault estimation for sensors and actuators and fault-tolerant control for one type of electrified ground vehicle, i.e., the in-wheel motor electric vehicle. First, the prototype in-wheel motor electric vehicle is presented and the experimental platform is discussed. Then the problem of sensor fault estimation and reconstruction of contaminated signal is studied. Yaw rate signal is chosen as the contaminated signal and a robust gain-scheduling observer is proposed accordingly. Second, the steering motor fault estimation approach is developed, since steering motor faults always impose a great threat to vehicle stability and safety. Furthermore, fault-type identification is also considered, which can provide detailed information of the type and magnitude of the actuator fault. Last, to deal with actuator fault and recover the faulty vehicle, an active fault-tolerant control system is proposed for the in-wheel motor electric vehicles. It uses a baseline controller to accommodate actuator faults and stabilize the faulty vehicle when an actuator fault occurs. Actuator fault is detected and estimated by the fault detection and diagnosis mechanism. After that, a proper reconfigurable controller is switched to recover the faulty vehicle. The proposed sensor and actuator fault estimation approaches and active fault-tolerant control system have been validated through simulations in CarSim® and/or vehicle experimental tests on the electric vehicle. Future works and directions are given, which may further address the problems discussed in this dissertation.