为实现火星采样返回任务中火星上升器热发射过程的高精度地面模拟, 该文提出一种包含水平随动机构的5索驱动低重力模拟试验装置。该文基于运动学和动力学建立了动态误差传递模型, 分析了水平随动机构位移误差、索力误差和外扰力对火星上升器6自由度轨迹精度的影响, 并提出了基于模型预测的动态误差限求解方法。仿真结果表明：单误差源/多误差源作用下模型计算与多体动力学仿真所得的误差曲线均吻合, 随机正弦波误差源输入下轨迹误差均位于理论误差限内, 验证了动态误差传递模型和动态误差限求解方法的有效性。该文研究结果可为试验装置的可行性评估及误差综合提供理论依据, 也可为后续控制优化和工程应用提供参考。

Objective: Mars sample-return missions require high-precision ground testing of the Mars Ascent Vehicle thermal launch process to verify key technologies in a low-gravity environment. This task requires a simulation mechanism with high operating speed, large stroke, and heavy load, which aligns well with the advantages of cable-driven mechanisms. However, although dynamic error analysis is critical for the early-stage design of such cable-driven systems, it has not been fully discussed—specifically regarding trajectory accuracy under the influence of multiple time-varying error sources. This study aims to design a low-gravity ground test facility and develop a dynamic error calculation method for evaluating the facility's feasibility for Mars Ascent Vehicle thermal launch simulations. Methods: In this study, a test facility that is driven by five cables and equipped with a horizontal follow-up mechanism is presented. The system consists of a test tower, a fixture for inclined launch, a cable-suspension gravity unloading system, and a cable-driven thrust-simulation system. Kinematic and dynamic models are developed to depict the six-degree-of-freedom motion of the Mars Ascent Vehicle mockup. The dynamic error propagation model is obtained through first-order perturbation expansion around the nominal trajectory, considering displacement errors of the two horizontal platforms, cable force fluctuations, and external disturbances as error sources. A model-predictive approach based on linear time-varying system discretization and linear programming is used to determine dynamic error bounds for trajectory deviations. The dynamic error propagation model is verified using the error calculation results of the model under single and multiple error sources, with a multibody dynamics model established in Maplesim as a reference. Tests for a random sine wave error input are also conducted through simulation to verify the effectiveness of dynamic error bounds calculated by the proposed method. Results: Theoretical analysis showed that an approximately linear propagation relationship existed between the error sources and the Mars Ascent Vehicle trajectory error in the test facility, which enabled the decomposition of error analysis problems under complex error sources into individual analysis problems under single-error-source conditions. When each error source acted independently, the maximum displacement error for each degree of freedom during the Mars Ascent Vehicle thermal launch process mostly increased over time, which was consistent with the error accumulation effect. The effects of different error sources displayed significant magnitude variations. The simulation results further revealed the following: (1) Under the conditions of single-and multiple-error sources, the trajectory errors computed by the dynamic error propagation model agreed well with those from the dynamics simulations, which suggested the effectiveness of the model in characterizing the error transmission mechanisms of the test facility. (2) When random sine wave error sources within specified amplitude ranges were presented, all the Mars Ascent Vehicle trajectory errors persisted within the theoretical error bounds forecasted by the proposed method, which demonstrated its capability to produce reliable dynamic error range estimates for uncertain environments. Conclusions: This study offers a design scheme for cable-driven ground test facilities for spacecraft. The dynamic error analysis of the facility reveals its error propagation mechanism, which lays a foundation for its error synthesis, optimization of mechanical structures, and control method design. In addition, this research also develops a generalizable theoretical framework for dynamic error analysis in similar cable-driven parallel mechanisms.