Design and verification of a seat suspension with variable stiffness and damping

This paper presents an innovative seat suspension with variable stiffness and variable damping (VSVD) via magnetorheological fluid dampers to enhance ride comfort. The VSVD seat suspension is developed based on an innovative structure with springs in series and damping units, and its principles of VSVD and vibration attenuation are evaluated theoretically. The proposed VSVD seat suspension is then manufactured and tested. The test results illustrate that the equivalent stiffness of the seat suspension with power on (I-s = 2.0 A current) increased to 186% and the equivalent damping (I-d = 1.0 A) raised to 520% compared to the seat suspension with no current applied. The evaluation of vibration-attenuation capability of the seat suspension is conducted by employing Fuzzy logic controls and both harmonic and random signals are considered as vibration excitations. The experimental data show that the proposed seat suspension with controlled stiffness and damping results in lower seat acceleration compared to a passive seat or one with traditional damping control.