Active steering wheel shimmy control for electric vehicle by sampled-data output feedback

Area of Science:

• Automotive Engineering
• Control Systems Theory
• Mechanical Vibrations

Background:

• Shimmy instability in electric vehicle (EV) steering systems poses a significant safety risk.
• Independent suspension systems in EVs can be susceptible to complex dynamic disturbances.
• Existing control methods may not adequately address uncertain disturbances in EV steering dynamics.

Purpose of the Study:

• To develop a robust two Degree of Freedom (DOF) shimmy dynamic model for EVs with independent suspension.
• To propose an active control strategy using a sampled-data output feedback controller to mitigate shimmy.
• To ensure global stability and disturbance attenuation in the EV steering system under uncertain conditions.

Main Methods:

• Modeling the EV steering dynamics using Lagrange's theorem.
• Designing a sampled-data output feedback controller for active shimmy suppression.
• Employing the output feedback domination approach with a scaling gain to handle uncertain disturbances.
• Calculating optimal sampling periods and scaling gains for system stability.

Main Results:

• A validated two DOF shimmy dynamic model for electric vehicles was established.
• The proposed sampled-data output feedback controller effectively suppressed steering shimmy.
• The control strategy demonstrated significant disturbance attenuation capabilities.
• Simulations and tests confirmed the controller's effectiveness under various operating conditions.

Conclusions:

• The developed dynamic model accurately represents EV steering shimmy.
• The active control method provides a viable solution for mitigating shimmy instability in EVs.
• The controller ensures robust performance and enhances steering safety in electric vehicles.