Design and optimization of stable initial heliocentric formation on the example of LISA

Space-based gravitational wave (GW) detector such as the LISA (Laser Interferometer Space Antenna) mission requires high-precision and stability of the triangular formation. The dynamic environment of the detectors is complex, the science requirements for the formation are tight, and consequently, design and optimization of this high-standard formation with essentially many decision variables are very challenging. This paper studies the design and optimization of the stable initial formation of the heliocentric GW detector by taking the LISA as an example. The linearization method based on relative orbital elements is used for formation design in the two-body system. Three constraints are presented to reduce the number of decision variables to fourteen. The geometric features of the arm length and breathing angle of the triangular formation and the relative position of LISA to the Earth are analyzed and numerically verified in a high-fidelity dynamic model, from which the relationships of multiple requirements of LISA are studied, and a single index is summarized to simplify the optimization. Sobol sensitivity analysis is used to quantitatively evaluate the sensitivities of the decision variables to the cost function, with which a self-adaptive adjustment algorithm of the region of the variables is presented to improve the computational efficiency. The availability of the method to quickly and precisely find a stable initial formation in an extensive neighborhood of the nominal formation is verified by numerical simulation, where the best solution decreases about 47.54% of the arm length change from the requirement. This study shows that the initial formation should be deployed appropriately away from the Earth, and the gravitations of Venus and Jupiter should be utilized to maintain the formation stability.     

编队星座星间相对状态测量的间接实现

研究利用编队卫星间伪距测量值 ,自主确定编队星座星间相对状态的有关问题。文中针对编队星座的卫星之间存在发射和接收天线不能相互覆盖的情况 ,提出了间接覆盖概念。并给出系统的数学模型 ,分析实现间接覆盖的方法并进行协方差分析。最后 ,对间接覆盖情况作了仿真 ,仿真结果证明间接覆盖在星间相对状态测量中的可行性     

水面无人艇集群编队控制技术综述

随着海上作业任务的日渐复杂以及水面无人艇控制理论的发展，单水面无人艇航行控制能力的局限性逐渐显现，集群编队控制技术得到了广泛关注。针对水面无人艇集群编队控制技术，分析了当前国内外应用情况与技术研究现状，重点从典型编队队形适用性、编队控制系统结构形式、编队协同控制方法、编队控制通信技术及异构条件下协同控制技术等方面分析了水面无人艇集群编队控制技术的研究进展。最后，进行了总结和展望，以期为水面无人艇集群编队控制技术的研究提供有益的参考。     

基于预设性能控制的超紧密航天器编队防避撞协同控制

研究了考虑具有外界干扰和防避撞约束的近地轨道超紧密航天器构型控制问题,将反步控制技术、预设性能控制相结合,提出了一种基于预设性能鲁棒控制的六自由度编队协同鲁棒控制方法。首先,给出了近地轨道完整的编队航天器相对位置和相对姿态非线性动力学方程,并根据状态约束条件转换了相对位置动力学模型。其次,设计了预设性能函数,通过误差转换,建立系统等效误差模型,基于反步法设计了预设性能鲁棒控制器,进一步应用Lyapunov稳定性定理证明了其闭环系统的一致最终有界性。最后在MATLAB/Simulink平台上进行了仿真验证,结果表明了方法的有效性。