An Adaptive Seat Suspension System for the Mitigation of Whole-Body Vibration

This paper presents the development, and design optimization of a novel MRE-based semi-active seat suspension system to mitigate the whole-body vibration (WBV) transmitted to the helicopter’s pilot. The semi-active seat suspension system includes an MRE-based isolator along with “parallel-series passive springs” to mitigate the vibration transmitted to human body. The proposed suspension system permits relatively large strokes for the suspension system to tolerate the human body’s weight, while maintaining the MRE to be operated within its linear deformation range. To this end, several MRE samples with 25% volume fraction of iron particles were fabricated and characterized under shear mode. A field- and frequency-dependent phenomenological model is developed to predict the MREs’ mechanical properties (storage and loss moduli) as functions of the excitation frequency and applied magnetic field. The proposed model permitted design optimization of a C-shaped MRE vibration isolator. The MRE isolator along with the three passive springs were optimally designed with large strokes of 15mm. Results showed that by increasing the applied current from 0 to 2A, the equivalent stiffness of the adaptive seat suspension increased from 8.94kN/m to 17.5kN/m. The system resonance frequency shift from 1.76Hz to 2.27Hz, corresponding to a frequency shift percentage of 29%.