【摘要】 载人的大惯量Stewart平台,多采用液压伺服系统驱动,其必然存在液压-机械综合谐振问题。这是由于油液的可压缩性、传动铰链的弹性及负载惯性等引起的。本文首先根据力-变形关系推导出Stewart平台的刚度矩阵,然后分别根据铰链和液压缸各自组成构件的串并联关系,推导出三维万向铰链和液压弹簧刚度的数学模型。进而建立了液压Stewart平台的无阻尼动力学方程,并据此研究了系统的综合谐振频率。理论计算与实验结果表明,平台的位姿、油液与铰链的刚度等因素决定了系统的综合谐振频率。更多还原

【Abstract】 The large inertia Stewart platform is usually driven by a hydraulic servo system,which inevitably brings about the hydraulic and mechanical resonance problem caused by the condensability of oil,the elasticity of transmission joints and load inertia etc.The paper derived the stiffness matrix of the Stewart platform from the relationship between force and deformation and then the mathematical models for the stiffness of a universal 3D joint and a hydraulic spring respectively from the serial and parallel relationships between the joints of a limb and the components of a hydraulic cylinder.As a result,the undamped motion differential equation for the hydraulic Stewart platform was obtained,thus analyzing the synthetical resonance frequency of the hydraulic servo system.The calculation results show that the system’s synthetical resonance frequency depends on such factors as the position and orientation of the platform,the stiffness of the joint and the oil.更多还原