The Movable lunar landing leg is a novel multi - closed parallel mechanism with sub-closed loop. Moreover, there are multiple passive and active joint variables in the mobile lunar landing legged mechanism (MLLLM), Due to the complex dynamic relationship between the passive joint variables and the active joint variables, it is difficult to derive the dynamic modeling of parallel mechanisms by the non-redundant parallel mechanism using the traditional Lagrangian formulation method. In order to solve this problem, the utilization of the virtual work principle makes the application of the Lagrangian formulation for parallel mechanisms possible and efficient. The MLLLM is divided into several serial open-loop sub-chains. Explicit dynamic equations of each sub-chain can be derived by using the Lagrangian formalism straightforwardly with respect to their own local generalized coordinates. Secondly, when transforming between different generalized coordinates, the dynamic equation is transformed into different coordinate subsystems by using the principle of virtual work, and the Jacobian matrix and Hessen matrix are introduced as constraints to ensure the explicit form of the dynamic equation, by combining the differential dynamics equations of each subsystem with the virtual work principle, the explicit dynamics model of the MLLLM under the active generalized coordinates is obtained. Finally, the position error of the end-effector caused by the active and passive joints of the parallel mechanism was evaluated. Compared with the previous methods, the inverse dynamic analysis formula presented in this paper is more concise, the calculation efficiency is higher, and the position error evaluation method is more accurate than the traditional method.

可移动的月球着陆腿是一种新颖的多闭合并联机构，具有亚闭合回路。此外，在移动登月着陆机构（MLLLM）中存在多个被动关节和主动关节变量，由于被动关节变量和主动关节变量之间复杂的动力学关系，因此很难通过并行推导得出并联机构的动力学模型。使用传统拉格朗日公式化方法的非冗余并行机制。为了解决这个问题，虚拟工作原理的利用使得拉格朗日公式在并行机制中的应用成为可能和有效。MLLLM分为几个串行开环子链。可以通过使用拉格朗日形式主义直接针对其自身的局部广义坐标来导出每个子链的显式动力学方程。其次，在不同的广义坐标之间进行变换时，利用虚功原理将动力学方程转化为不同的坐标子系统，并引入雅可比矩阵和黑森矩阵作为约束条件，通过结合动力学方程来保证显式形式。利用虚拟工作原理，求各子系统的微分动力学方程，得到主动广义坐标下MLLLM的显式动力学模型。最后，评估了由并联机构的主动和被动关节引起的末端执行器的位置误差。与以前的方法相比，