Fault Tolerant Control of Integrated Autonomous Wheel Module Vehicle Subject to Independent Steering Actuator Degradation

This study investigates the issue of fault-tolerant motion control in the distributed chassis system (DCS) subject to degradation in independent steering actuators. First, the dynamic behavior of the independent steering system is analyzed to establish a fault-dynamics model for independent steering. The steering powertrain degradation coefficient is then mapped to the contraction of the feasible tire-force region. Subsequently, the model predictive controller (MPC) is designed to solve for the required generalized forces/torques. Moreover, along the direction of the generalized demand force vector, the boundary values for the current cycle are obtained and used to correct the generalized demand force. Finally, an adaptive weighting scheme for the tire force distribution objective function, which accounts for degradation coefficients, is proposed. Sequential quadratic programming (SQP) is employed to achieve optimal utilization of tire forces. Simulation studies for different steering degradation scenarios and road conditions are conducted using a CarSim 2019 and Simulink 2021B co-simulation platform. The simulation results demonstrate that the proposed integrated chassis motion controller maintains excellent motion control performance even under independent steering actuator degradation.