For spatial multibody systems, the dynamic equations of multibody systems with compound clearance joints have a high level of nonlinearity. The coupling between different types of clearance joints may lead to abundant dynamic behavior. At present, the dynamic response analysis of the spatial parallel mechanism considering the three-dimensional (3D) compound clearance joint has not been reported. This work proposes a modeling method to investigate the influence of the 3D compound clearance joint on the dynamics characteristics of the spatial parallel mechanism. For this purpose, 3D kinematic models of spherical clearance joint and revolute joint with radial and axial clearances are derived. Contact force is described as normal contact and tangential friction and later introduced into the nonlinear dynamics model, which is established by the Lagrange multiplier technique and Jacobian of constraint matrix. The influences of compound clearance joint and initial misalignment of bearing axes on the system are analyzed. Furthermore, validation of dynamics model is evaluated by ADAMS and Newton–Euler method. This work provides an essential theoretical basis for studying the influences of 3D clearance joints on dynamic responses and nonlinear behavior of parallel mechanisms.

对于空间多体系统，具有复合间隙接头的多体系统的动力学方程具有高度的非线性。不同类型的间隙接头之间的耦合可能会导致丰富的动态行为。目前，考虑三维（3D）复合间隙接头的空间并联机构动力响应分析尚未见报道。这项工作提出了一种建模方法来研究 3D 复合间隙接头对空间并联机构动力学特性的影响。为此，推导出具有径向和轴向间隙的球面间隙接头和旋转接头的 3D 运动学模型。接触力被描述为法向接触和切向摩擦，后来被引入非线性动力学模型，它是由拉格朗日乘子技术和约束矩阵的雅可比建立的。分析了复合间隙接头和轴承轴线初始不对中对系统的影响。此外，动力学模型的验证通过 ADAMS 和 Newton-Euler 方法进行评估。这项工作为研究 3D 间隙接头对并联机构的动态响应和非线性行为的影响提供了重要的理论基础。