空间气动连续体机器人及其捕获特性研究

More on-orbit service will be needed for non-cooperative targets in the future, however, current space capturing systems couldn’t fully meet these requirements. Based on the built models for typical geometric features and probability distribution of non-cooperative targets in space, a new design for pneumatic continuum robot with self-adaptive capturing characteristics is presented. The nonlinear mechanical model for robot is established, and the influence law between structure parameters and mechanical properties is revealed. The stiffness and damping models for robot by parameter identification, meanwhile its equivalent kinematic model is built and the self-adaptive capture strategy is proposed. The contact force model of interaction zone between robot and grasping target is established to describe their interaction behavior from the view of microscopic point, and the force closure grasping criterion is acquired. To build the collision mechanics model during the grasping process and the grasping regulation is given with different grasping posture. The nonlinear dynamic model of combination bodies is established for the analysis of dynamic response and stability in space. The test platform is built to verify proposed methods and built models by different experiments, providing theoretical support for the space application in the debris cleaning and attack-defense filed with a number of non-cooperative target operation.

未来空间在轨服务会涉及更多针对空间非合作目标的操作，而现有的空间抓捕系统还无法完全满足这一需求。基于建立的空间非合作目标典型几何特征及其概率分布模型，提出一种具有自适应捕获特性的气动连续体机器人新构型，建立机器人非线性力学模型，揭示机器人结构参数对其力学性能的影响规律。通过参数辨识获得机器人的刚度和阻尼矩阵模型，建立机器人等效的运动学模型并提出自适应抓捕策略。建立机器人与抓持目标相互作用区域的接触力模型，从细观角度描述机器人与抓持目标的相互作用行为，获得机器人对目标实施可靠力封闭抓持的判据。建立抓持过程的碰撞力学模型，提出机器人不同抓持姿态下的抓持规程。构建抓持后形成的组合体非线性动力学模型，开展微重力环境下组合体的动态响应和稳定性分析。搭建地面模拟试验平台，采用试验手段验证本项目所提方法及建立模型的合理性和正确性，为我国在空间碎片清理、空间攻防等非合作目标操控领域工程应用提供理论支撑。

本项目针对典型的非合作目标几何外形，设计了多种气动连续体机器人结构进行对比。针对不同的机器人结构，分别建立其输入输出特性模型，并采用有限元分析的方法，对几何结构参数进行优化。为了解决气动连续体机器人刚度和载荷能力不足的问题，对于设计的不同软体机器人结构，本项目提出了响应的刚度增强方法。实验结果表明，本项目所提出的刚度增强方法可大幅度提高气动软体机器人的载荷承受能力。本项目结合刚性机器人的运动学建模方法，通过近似和简化建立了气动连续体机器人的从驱动空间到操作空间的运动学模型。为了实时监测运动学模型的精确性，本项目设计了一种基于液态金属的柔性传感器。通过检测柔性传感器的电阻变化情况，可实时测得每个检测点的传感器长度变化情况，进而通过运动学模型计算出气动软体机器人端部的位姿。本项目还建立了气动连续体机器人在抓取过程的碰撞动力学模型以及抓取后的组合体动力学模型，为气动连续体机器人的可靠抓取提供了控制基础。最后，本项目制作了多种气动连续体机器人样机，针对不同尺寸和外形的目标开展了抓取实验，实验结果验证了设计方法的可行性和理论模型的正确性。