Performance Evaluation of a Single Sensor Control Scheme Using a Twin-Tube MR Damper Based Semi-active Suspension

Abstract

Magneto-rheological (MR) dampers have a promising future for application in automotive semi-active suspensions. The damping force produced by MR dampers can be modulated by controlling the electric current supplied to it. The present work explores a twin-tube MR damper working in valve mode for application in a semi-active SUV suspension system. Further, the performance of a single sensor control scheme is evaluated. The MR damper is characterized in a damper testing machine to demonstrate the MR behaviour and also to show that it develops similar magnitude of force as a passive damper used in SUV suspension. To prove the superiority of semi-active suspension, a single degree of freedom quarter car test rig is built and ground excitation is given in the form of displacement input from a hydraulic actuator. Constant current control, Skyhook control and Rakheja-Sankar (RS) control method are employed as three different control strategies and compared with passive suspension to study the advantages. Peak acceleration response of the sprung mass is studied for better passenger ride comfort and peak ground force is studied for preventing damage to road surface as well as to vehicle suspension elements. RS control provides much lower sprung mass vertical acceleration than Skyhook control and constant current control. RS control method led to 36% reduction of peak ground force when compared to Skyhook control. For a semi-active suspension using twin-tube MR damper, RS control method provides better ride comfort to passengers due to lower peak vertical acceleration when compared to constant current control or Skyhook control method. Moreover, for preventing damage to road surface as well as to vehicle suspension elements, RS control method, requiring a single sensor, is a much better choice.