大角速度柔性航天器动力学模型修正

将拉格朗日方程及其准坐标形式用于中心刚体加柔性附件航天器的拉格朗日函数,推导了中心刚体加柔性附件航天器动力学模型。针对航天器大角速度,分析中心刚体角速度对角动量方程的影响,对传统动力学模型进行修正。航天器绕惯量主轴大角速度自旋仿真结果验证了修正后的动力学模型对于大角速度航天器的有效性。     

机动再入体的带落角约束扩展比例导引律设计

传统的各种制导律都是以获得最小脱靶量为最终目标,没有考虑到导弹击中目标时刻的末端落角.为了保证非自旋再入体完成精确打击目标的任务,针对非自旋再入体垂直打击目标的制导问题,设计了一种带落角约束的扩展比例导引律.仿真研究表明,所设计的末制导律能够保证非自旋再入体命中目标时的脱靶量和末端落角都能满足要求,可以为开展近空间非自旋再入体制导问题的研究提供测试平台.     

空间机器人抓取未知目标的质量特性参数辨识

根据动量守恒定理,研究了单臂自由飘浮空间机器人抓取未知目标的质量特性参数辨识问题。已有文献中基于动量守恒原理进行的参数辨识只适用于系统线动量和角动量为零的情况,当两者不为零时无法得到正确的辨识结果。为解决此问题,本文首先在惯性系而非本体系下推导得到了机械臂抓取未知目标后的系统线动量和角动量,保证了其各分量的守恒特性。然后基于此特性,通过在轨测量两个时刻机器人本体的线速度、角速度以及机械臂各关节的角速度和转角信息,建立了含有未知目标质量特性参数的动量增量方程。最后根据三组测量信息,从联立的动量增量方程组中求解得到未知目标的质量特性参数。数值仿真表明,此方法在系统线动量和角动量为零和不为零两种情况下都能实现高精度的参数辨识,同时还避免了方程求解的奇异问题。     

Coordinated Multiple Spacecraft Attitude Control with Communication Time Delays and Uncertainties

In this paper, we consider the coordinated attitude control problem of spacecraft formation with communication delays, model and disturbance uncertainties, and propose novel synchronized control schemes. Since the attitude motion is essential in non-Euclidean space, thus, unlike the existing designs which describe the delayed relative attitude via linear algorithm, we treat the attitude error and the local relative attitude on the nonlinear manifold-Lie group, and attempt to obtain coupling attitude information by the natural quaternion multiplication. Our main focus is to address two problems:1) Propose a coordinated attitude controller to achieve the synchronized attitude maneuver, i.e., synchronize multiple spacecraft attitudes and track a time-varying desired attitude; 2) With known model information, we achieve the synchronized attitude maneuver with disturbances under angular velocity constraints. Especially, if the formation does not have any uncertainties, the designer can simply set the controller via an appropriate choice of control gains to avoid system actuator saturation. Our controllers are proposed based on the Lyapunov-Krasovskii method and simulation of a spacecraft formation is conducted to demonstrate the effectiveness of theoretical results.     

基于角增量提取的旋转矢量算法研究

在某些由光纤陀螺或微机电陀螺组成的捷联航姿系统中,陀螺输出的是角速率。针对这种情况,归纳了基于角增量提取的二子样、三子样和四子样旋转矢量姿态算法,推导了这些算法的圆锥误差表达式,比较了它们的性能。     

基于落角约束的超声速导弹制导方案研究

针对超声速导弹具有落角约束条件下的制导问题,提出了一种新的设计方案.首先,在中制导俯冲过程中,采用攻击预先设定的虚拟目标方案,达到期望的中制导末端性能指标;然后,开始末制导俯冲段,雷达开机实时攻击实际目标,使导弹在需用过载和导引头框架角约束条件下,以期望落角命中目标.仿真结果表明,该制导律具有期望的性能要求,易于工程实现.     

基于ESO的DGVSCMG双框架伺服系统不匹配扰动抑制

针对双框架变速率控制力矩陀螺（DGVSCMG）两种工作模式下内、外框架系统存在的不匹配干扰抑制问题,提出一种基于扩张状态观测器与状态反馈的扰动抑制方法。在对飞轮工作模式和陀螺工作模式下内、外框架系统的干扰进行建模和分析的基础上,针对其不匹配干扰设计了扩张状态观测器,通过坐标变换减小框架系统扰动对不匹配通道的影响,并结合状态反馈控制设计了复合控制器,同时对全局系统稳定性进行了分析。对框架系统进行的仿真结果验证了所提复合控制方法的有效性。实验结果表明,所提出的控制方法能有效减小耦合力矩对内外框架角速率带来的影响,在飞轮模式下使得内外框架的角速率跳动量分别降低了85%和78%,且在陀螺模式下使外框架角速率跳动量降低了75%。     

Multi-coset angular sampling-based compressed sensing of blade tip-timing vibration signals under variable speeds

Blade Tip-Timing (BTT) has been regarded as a promising way of on-line blade vibration monitoring. But blind multi-band BTT vibration reconstruction is a big challenge under variable speeds and under-sampling. In order to deal with it, a novel Compressed Sensing (CS) method is proposed based on Multi-Coset Angular Sampling (MCAS) in this paper. First, multi-coset sampling scheme of BTT vibration signals is presented. Then the CS model of BTT vibration signals is derived in order domain. A sufficient condition of the number of BTT sensors is derived for perfect reconstruction and optimal placement of BTT sensors is determined by minimizing the condition number. In the end, numerical simulations are done to validate the proposed method and the performances of four reconstruction algorithms are compared, i.e., Orthogonal Matching Pursuit (OMP), Multiple Signal Classification (MUSIC), Basis Pursuit Denoising (BPDN) and Modified Focal Underdetermined System Solver (MFOCUSS). Influences of the sensor placement, the number of BTT sensors and measurement noises on the reconstruction performances are also testified. The results demonstrate that the proposed method is feasible and the overall performance of the BPDN algorithm is the best among the four algorithms. Also the reconstruction performance decreases with the accelerations of rotating speed.     

空间站组合体惯性系内角动量管理控制

针对惯性系内重力梯度力矩与气动力矩的常值部分积累引起控制力矩陀螺饱和的问题,在惯性系内建立空间站的动力学模型并进行线性化,利用滤波变量将系统状态方程扩维,采用LQR方法设计系统反馈控制增益矩阵,实现空间站在惯性系内的角动量管理控制.惯性系内重力梯度力矩、气动力矩由轨道角速度整数倍的频率成份构成,可以根据实际情况增加抑制不同频率成份的滤波变量,用于抑制不同频率成份干扰力矩对空间站姿态或控制力矩陀螺角动量的干扰,从而使空间站长期在惯性系内飞行而不需要进行角动量的卸载.仿真验证了控制器的性能.     

联合载荷作用下精密角接触球轴承动态特性演变规律

基于滚动体与套圈之间相互作用与相对位置关系,考虑离心力、陀螺力矩等非线性因素影响,建立了精密角接触球轴承五自由度拟静力学分析模型,并基于逐步搜索法原理对轴承刚度计算模型进行优化,揭示了复杂联合载荷作用下精密角接触球轴承动态特性的演变规律。研究表明:轴向载荷在一定程度上减小轴承内外圈接触角差值,削弱由于转速增大引起的刚度软化现象;力矩载荷与径向载荷单独作用时,均导致轴承接触角、接触力波动幅度增大,沿载荷作用方向轴承刚度增大,垂直于载荷作用方向刚度减小;联合载荷作用下,力矩载荷能够抑制径向载荷引起的轴承内部载荷波动,提高轴承承载能力与使用寿命。