本文以火星探测器着陆过程中的防热大底分离和背罩分离为背景，针对分离过程中面临的不确定风险，采用7索驱动机器人开展地面模拟实验。在构建出基于索驱动机器人的地面模拟实验装置后，系统地对绳索的静态索力传递特性、动态索力传递特性、扰动力的设计和施加策略等开展理论研究工作，并对所建理论模型进行实验验证。以背罩轴向分离为背景，建立索驱动机器人基本运动学模型，并基于有限元法和牛顿运动定律推导绳索的动力学模型，利用假设模态法，给出索力传递的表达式。提出用于评价静态索力传递特性的指标定义：静态索力超调量、静态索力相应时间和静态索力平均相对误差。采用数值计算的方法探索了绳索杨氏模量、绳索线密度、预紧力、绳索长度和负载等因素对静态索力传递特性的影响规律。并采用索驱动机器人对所建理论和模型进行实验验证。以防热大底轴向分离为背景，根据所提出的绳索动力学模型，针对防热大底的短期分离阶段和长期分离阶段，推导相关的边界条件和初值条件，并针对短期分离阶段中可能出现的绳索松弛现象，给出相应的处理方法。提出用于评价高速动态索力传递特性的指标定义：索力松弛时间、索力峰值、动态索力平均相对误差。采用数值计算的方法探索火工品推力、绳索杨氏模量和预紧力等因素对高速动态索力传递的影响规律。并采用索驱动机器人对绳索动态索力传递特性的研究内容进行实验验证。以防热大底和背罩分离过程中扰动力的模拟为背景，设计一种新型的扰动力施加单元，提出扰动力可控工作空间的定义，并给出工作空间质量系数的计算方法，用于评价末端执行器到达扰动力可控工作空间边缘的接近程度，作为扰动力施加稳定性的性能指标，并对扰动力施加单元的数量和位置布局进行优化分析，最后给出相应的扰动力施加策略。通过仿真计算的方法分析轴向力、扰动力、和扰动力矩对末端执行器位置和姿态的影响，并通过防热大底和背罩的模拟件对所建模型的正确性和有效性进行实验验证。基于本文所提出的主要理论，以防热大底和背罩的真实件进行最后的实验验证，实验结果满足相关技术指标，为我国火星探测任务的地面模拟实验提供了理论指导和借鉴。
In this paper, a 7-cable driven robot is used to conduct ground simulation experiments for the uncertain risks during the separation process with the background of heatshield separation and backshell separation in the Mars exploration mission. After constructing the ground simulation experimental equipment based on the cable-driven robot, we systematically carry out theoretical research on the static cable force transmission characteristics, dynamic cable force transmission characteristics, design and application strategy of disturbing forces. Finally, experimental validation of the proposed theoretical model is carried out.The basic kinematic model of the cable-driven robot is established in the context of axial separation of the backshell. The kinetic model of the cable is derived based on the finite element method and Newton's law of motion. Using the assumed mode method, the expressions for the transmission of the cable force are given. The definition of the indexes used to evaluate the static cable force transmission characteristics: static cable force overshoot, static cable force corresponding time and static cable force average relative error are proposed. The influence of Young's modulus, cable density, pretention, cable length and load on the static cable force transmission characteristics is explored by numerical calculation. The proposed theory and model are experimentally verified by using a cable-driven robot.In the context of the axial separation of the heatshield, the relevant boundary conditions and initial conditions are derived for the short-term separation and long-term separation of the heatshield according to the proposed cable dynamics model. The treatment method is given for the cable slack phenomenon that may occur in the short-term separation. The definitions of indexes used to evaluate the high-speed dynamic cable force transmission characteristics are proposed: slack time of cable force, peak cable force, and average relative error of dynamic cable force. Numerical calculation method is used to investigate the influence law of thrust, Young's modulus and pretension on high-speed dynamic cable force transmission. Using the cable-driven robot as the research object, the research content of the dynamic cable force transmission characteristics of the cable is verified through experiments.A novel disturbing force application unit is designed in the context of the simulation of disturbing force during the separation of heatshield and backshell. The definition of the disturbing force controllable workspace is proposed and the calculation method of the workspace quality coefficient is given for evaluating the proximity of the end-effector to the edge of the disturbing force controllable workspace. It depicts the stability of the disturbing force. The number and location layout of the disturbing force application units are optimized and analyzed. Then, the corresponding disturbing force application strategy is given. The effects of axial force, disturbing force, and disturbing moment on the position and orientation of the end-effector are analyzed. Finally, the correctness and effectiveness of the proposed model are experimentally validated. Based on the main theory proposed in this paper, real heatshield and backshell are used to implement experimental verification. The experimental results meet the relevant technical indexes. The contributions in this paper provide theoretical guidance and reference for the ground simulation experiments of China's subsequent Mars exploration missions.
