Nonlinear Dynamic Analysis of a Novel Multi-coupled Quadrupedal Bio-inspired Vibration Isolation Platform

In order to achieve ultra-low and broadband frequency vibration suppression, a structurally compact and parameter-adaptable Multi-coupled Quadrupedal Bio-inspired Vibration Isolation platform (MQBVI) based on the mechanical features of the quadruped is proposed in this research. Due to the large working stroke and strong nonlinearity of the platform, the virtual work method and incremental harmonic balance method are utilized to systematically analyze the static and dynamic characteristics, respectively. The comparison validations of bio-inspired platform are conducted by Incremental Harmonic Balance Method (IHBM), ADAMS, numerical method and physical prototype. The investigation revealed that the restoring force and equivalent stiffness are nonlinear and asymmetrical, which lead to the MQBVI platform exhibits superior High Static Low Dynamic Stiffness (HSLDS) characteristics and strong stability. The vibration suppression performance of the MQBVI structure is investigated with installation angle, spring stiffness, connecting rod length, isolated mass and excitation amplitude, which exhibits low resonance frequency and wide effective vibration attenuation frequency band. Notably, the minimum critical values of resonance frequency and vibration suppression effect are reduced to 0.27 Hz and 0.39 Hz with α = 30°, respectively. Overall, the proposed MQBVI platform is an efficient ultra-low frequency vibration suppression structure with excellent adaptability, and the bio-inspired vibration buffering and isolation mechanism are revealed.