面向火星着陆器触地模拟试验的重力卸载系统  

A designed gravity compensation system for landing preview of Mars lander

作　　者：隋毅[1,2] 孙海宁 黄伟 董强[4] 黎光宇 张剑勇 张亚婧[1,2] SUI Yi;SUN Haining;HUANG Wei;DONG Qiang;LI Guangyu;ZHANG Jianyong;ZHANG Yajing(Beijing Institute of Space Mechanics&Electricity,Beijing 100094,China;Laboratory of Aerospace Entry,Descent and Landing Technology,Beijing 100094,China;Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China;Beijing Institute of Special Engineering Design and Research Institute,Beijing 100028,China)

机构地区：[1]北京空间机电研究所,北京100094 [2]航天进入减速与着陆技术实验室,北京100094 [3]清华大学机械工程系,北京100084 [4]北京特种工程设计研究院,北京100028

出　　处：《清华大学学报（自然科学版）》2023年第3期406-413,共8页Journal of Tsinghua University(Science and Technology)

基　　金：载人航天领域第四批预先研究项目(060201)。

摘　　要：在地面环境下开展可靠且快速的验证试验是保障探测器成功着陆的关键。该文基于零自由长度弹簧模拟“天问一号”火星着陆的重力卸载系统,在触地阶段为探测器提供火星表面的重力环境,破解卸载力在触地及剧烈碰撞过程中平稳、恒定输出的技术难题,利用弹簧对冲击力等高频干扰的截断能力,使重力卸载系统在剧烈动态过程中保持平稳的输出。试验结果表明:系统的恒力输出最大平均误差为1.5%,可有效保障大行程、重载、高速和冲击条件下恒定卸载力的施加。系统的负载可调设计可适配不同目标行星的重力环境,提高了相关触地模拟的试验效率。[Objective] The Tianwen lander has to follow the same sequence as most space missions landing on other planets(or back on Earth), a process known as Entry, Descent, and Landing. NASA engineers have described the descent of the Mars landing missions as “seven minutes of terror” as it is the most unpredictable. About 20 attempts to land on Mars have been made by different countries so far. Besides a considerably thinner atmosphere, Mars’ s gravitational field is weaker than that of Earth;thus, on average, it delivers 38% as much downward acceleration. In this paper, a large-scale gravity compensation system is designed to simulate the Martian environment to test the Tianwen-1 lander during the Mars landing. [Methods] Considering severe collisions and abrupt changes of states during the landing, the system uses multiple elastic elements, including springs, to eliminate undesired high-frequency vibrations, thereby enabling the system to maintain a stable output during severe dynamic processes. The compensation system is composed of an adjustment mechanism, springs, guide bar, wire rope, and oscillating bar. To achieve the target stiffness, five springs are used in parallel. By adjusting the adjustment mechanism, the initial preload of springs can be varied to match different loads with masses varying within a certain range. The guide bar can restrain the lateral movement of the spring, thereby ensuring that it maintains a stable state during shortening and elongation. Additionally, it can also offset the weight of the springs. Conversely, the equivalent replacement of the zero-free-length spring enlarges the stroke of the system. To achieve the equivalent replacement of the zero-free-length spring, an additional mechanism and pulley are designed. Then, the mechanical properties are explored from the perspective of energy conservation. Eventually, the relationships among the characteristic values of each component in the system can be determined. [Results] Three major issues had been resolved by the gravity comp

关 键 词：火星着陆器 触地模拟 重力卸载 恒拉力 

分 类 号：TH113[机械工程—机械设计及理论]