Dynamic stability and vibration isolation property of a foot-leg coupling bio-inspired vibration isolation structure

Inspired that Kangaroo could buffer the shock and vibration from ground and keep the body and head steady and low/wide-frequency vibration isolation performance, a novel foot-leg coupling bio-inspired vibration isolation (FLBVI) system is proposed considering the synergy among skeleton, ligament/muscle and articulation. Based on the statics model, the static properties are investigated, and the idealized loading capacity and quasi-zero stiffness (QZS) range could be easily obtained by adjusting structure parameters. Combining with the dynamic model, the dynamic equation of the FLBVI structure is derived by Lagrange principle, and the nonlinear properties are analyzed by incremental harmonic balance method (IHBM). Based on verifying validity and feasibility of theoretical model with experiment results, the dynamic behaviors and vibration isolation performances of FLBVI structure are revealed from the visual angle of resonance characteristic and displacement transmissibility under different parameters. The results show that the FLBVI could availably reduce response amplitude, broaden the vibration isolation bandwidth, and then improve vibration isolation performance (below 5 Hz) and stability with proper parameters. The research of the FLBVI structure provides an innovative strategy of the designing bio-inspired vibration isolation structure.