Wobble of a spin stabilized satellite with cross products of inertia and magnetic attitude control

Asymmetrical spin stabilized satellite dynamics in the vicinity of the required motion is considered. The principal axis of the maximum moment of inertia slightly deviates from its assumed direction in the satellite reference frame. This is formalized in the cross products of inertia. This inertial uncertainty results in a wobble, that is undesired angular velocity components perpendicular to the rotation axis, and oscillations of this axis near the required direction. The torque-free motion is investigated first. Expressions that explicitly relate satellite inertia parameters to wobble are provided. Wobble evolution under the action of magnetic damping control is analyzed next. Its amplitude approximate exponential decay behavior and residual unavoidable wobble level are derived. These expressions are compared with numerical simulation results of nonlinear equations of motion including various disturbance sources.     

求解非稳态对流占优问题的非标准无网格Galerkin方法

用θ加权法离散时间域,并将四种稳定化方案与无网格Galerkin方法相耦合进行空间域的离散。在无网格Galerkin方法中,采用线性基和具有连续的权函数,基于移动最小二乘法构造了高阶导数连续的形函数,从而避免了有限元方法中采用线性元插值时,因忽略稳定项中二阶导数项而降低计算精度的问题。数值计算表明:本文构造的方法成功地消除了非定常对流扩散方程中对流项占优时的数值伪振荡现象,并具有计算精度高、稳定性好、算法实施简单、前后处理方便的优点。特别是所构造的MFLS方法非常适宜于求解非定常的对流扩散方程。     

滞后不确定组合大系统的鲁棒控制

本文讨论了具有时滞互联不确定组合大系统的镇定问题。这种不确定性是时变的,它可作为不确定参数及输入摄动存在于每个子系统中,也可能存在于互联项中。不确定性在假设可能知道它的边界的情况下,利用本文构造的线性分散状态反馈控制律,系统是实际可稳定的,即系统可镇定。     

光学稳像技术在空间通信及航空、航天中应用的探讨

论述了光学稳像的一般概念，并给出了分析稳像问题的普遍公式，解决了空间通信及航空、航天相机的稳瞄及图像稳定问题．实际算例表明，光学稳像技术可普遍应用到空间技术中，可为稳像光学系统的设计提供重要的理论基础。     

A heuristic design method for attitude stabilization of magnetic actuated satellites

In this paper a heuristic design strategy for stabilizing the satellite attitude has been proposed. It is assumed that the satellite is actuated by a set of mutually perpendicular magnetic coils. Using well-known Lyapunov direct stability method it is shown that the proposed controller causes to a global asymptotic stable system for all near polar orbits. The design procedure is based on analyzing of the conceptual effects of magnetic coils on the satellite attitude motion. Considering these effects lead to some intuitive results which determine the global stabilizing control law. The performance and robustness of the designed controller against actuators saturation and quantization error have been verified using a real-time-hardware–software in-loop (RTHSIL) simulation results. These results show that the global stability can be achieved although some disturbances and restrictions exist. This stabilizing controller can be simply combined with a linear explicit model predictive controller (EMPC) to achieve a full three-axis control law.     

高速精密激光干涉测量的研究现状及其关键技术

总结了高速精密激光干涉测量的研究现状；分析了影响测量精度和提高测量速度的主要因素及解决问题的关键技术，包括激光稳频技术和光学反馈、精度与测速的制约关系、空气折射率的影响及补偿、电子细分技术、光学非线性误差等     

采用 CARMH 模型的广义最小方差自校正控制器的全局收敛性

在一种新的预测模型的基础上，建立了一般的广义最小方差自校正控制器，并证明了当辨识算法采用随机逼近法时这种自适应算法的全局收敛性，从而为这种新型模型的进一步应用提供了一定的理论依据。     

工业废渣制备软土地基固化剂设计方法探讨

探讨了拟加固土的化学性质因素对固化剂水化物生成的影响和对策、形成最佳固化土结构需要的水化物体系特点、不同种类水化物生成过程的协调性及调控方法.在此基础上,根据工业废渣在制备软土固化剂中的技术优势,提出了利用工业废渣制备软土地基固化剂的设计思想与方法,并给出设计实例.试验结果表明利用工业废渣制备固化剂时采用本设计方法,固化土28d无侧限抗压强度比水泥固化土提高了1.5~2.75倍.     

区间离散系统的鲁棒控制

用值集凸分析方法研究了区间离散系统鲁棒镇定问题。当系统传函仅低次项系数受扰时,导出了一阶控制器鲁棒镇定区间系统的顶点结果,并举例说明了控制器的设计方法.     

小型控制力矩陀螺扰动建模及性能指标分析

为实现遥感卫星的高精度指向能力,对遥感卫星星上常用执行机构控制力矩陀螺扰动及性能指标评定进行了研究。首先,充分考虑小型控制力矩陀螺的静动不平衡量以及框架轴的安装误差,根据动量定理和动量矩定理建立了完整的星载小型控制力矩陀螺的动力学模型,并对所建立模型的正确性进行了理论分析和仿真验证;其次,将含有扰动特性的小型控制力矩陀螺应用到星上,建立了整星动力学模型,并选用合适的框架伺服控制系统和转子伺服控制系统,完成整星的姿态稳定控制任务;最后,采用数值仿真的方式分析了陀螺转子静动不平衡因素以及框架角测量误差对星体姿态精度和稳定度带来的影响。结合任务要求,对小型控制力矩陀螺设计提出静动不平衡量等指标要求,以期使其满足星上光学有效载荷的成像要求。