Adaptive pneumatic vibration isolation platform

Abstract

Abstract A novel adaptive pneumatic vibration isolation platform (APVIP) which is built by combining two opposite stiffness mechanisms is proposed. The positive stiffness mechanism including the wedge, the roller and the air spring is used to support the load (named load bearing mechanism LBM) meanwhile the dynamic stiffness of the APVIP can be reduced by introducing a stiffness correction mechanism (SCM) configured the negative stiffness comprising the cam, the roller and the air spring. The significant feature of the APVIP is explored that both its easily adjusted stiffness according to the mass variation of the isolated object and its improved isolation effectiveness. The paper presents theoretical and experimental analyses of the proposed system. Firstly, the pneumatic-mechanical model of the LBM and SCM is analytically expressed, then, the original and approximate restoring forces of the proposed model are found. Secondly, the dynamic equation of the platform is obtained and the Normal form method is used to analyze the primary resonance response of the APVIP. Simultaneously, due to the nonlinear dynamic system, the numerical integration and Poincare map are employed to analyze the complex dynamical equation including coexistence of solutions and bifurcation phenomena. Next, an experimental apparatus has been set up to verify theoretical model and simulation. Finally, the results demonstrate that the APVIP outperforms the equivalent isolation platform without SCM (shorten platform without SCM).