考虑关节间隙的多维隔振系统振动特性分析

Vibration characteristics analysis of multi-dimensional vibration isolationsystem with joint clearance

为隔离车载精密仪器承受的多维振动,引入基于并联机构且考虑机构关节间隙的多维被动隔振系统。通过GF集(Generalized Function Set)型综合理论,得到一种具有三平移一转动运动特性的4-PUU(移动副-虎克副-虎克副)并联机构,在主动关节处添加弹簧和黏滞阻尼器,建立考虑关节间隙的多维隔振系统运动学和动力学方程,研究存在关节间隙的多维隔振系统在谐波、随机路面激励下的时域、频域隔振能力。研究结果表明:存在关节间隙的多维隔振系统能够实现多维振动在时域和频域中的有效衰减;随着关节间隙数值逐渐增大,隔振能力沿x轴方向变化最敏感,沿y轴方向变化最不敏感;系统第一阶共振峰对关节间隙变化敏感,向低频区域移动,隔振能力恶化。

Aiming at reducing multi-dimensional vibration experienced by vehicle-mounted precise instrument,a multi-dimensional passive vibration isolator is built based on parallel mechanism with joint clearance.The 4-PUU parallel mechanism with axes 45°offset value,which exhibits three translations and one rotation characteristics is synthesized by GF set type synthesis theory.The springs and viscous dampers are added on the active joints,meanwhile the kinematics and dynamics of the multi-dimensional vibra-tion isolator are established.The vibration isolation capability with different values of joint clearance under harmonic and road ran-dom excitations is addressed.The results demonstrate that the proposed multi-dimensional isolator with joint clearance can inhibit multi-dimensional vibration in time and frequency domain significantly.As the value of joint clearance increasing,the vibration iso-lation capability degenerates,especially in x direction.Meanwhile,the first order resonance peak is sensitive to joint clearance,which shifts to low frequency range.