Impacts of the Observation of the Steering Torque Disturbance on the Stability of a Time-Delayed Control System for a Corner Module with Steering

Corner modules decouple chassis functions and enable independent wheel steering, but their control is highly sensitive to external disturbances and feedback delays. Disturbance observers (DObs) are often introduced to mitigate such disturbances, yet their additional dynamics can also compromise closed-loop stability when delays are present. This paper establishes the closed-loop control system of a corner module steering system based on its dynamics, designs the corresponding control law, and incorporates a DOb. Classical stability analysis is carried out using D-curve mapping and eigenvalue validation. The results reveal that feedback delay progressively shrinks the stable domain. When a DOb is introduced, disturbance rejection is improved; however, the admissible control gain region becomes narrower, and larger observer gains further constrain the derivative action, generating additional unstable regions. This paper mechanistically elucidates the impact of disturbance observation on the stability of a time-delayed control system for a corner module with steering.