Adaptive Spacecraft Attitude Tracking Controller Design Based on Similar Skew-symmetric Structure

This article presents an adaptive attitude tracking controller with external disturbances and unknown inertia parameters. The similar skew-symmetric structure is extended from the autonomous case to the non-autonomous case. The non-autonomous similar skew-symmetric is chosen as the desired structure of the closed loop system for attitude controller design. Based on this structure, a novel adaptive backstepping scheme is proposed to design the attitude controller by taking full advantage of the symmetry and the positive definiteness of the inertia matrix. The attitude tracking precision is enhanced by employing the linear parameterized form of the external disturbance torques. Simulation results demonstrate the effectiveness of the proposed attitude controller.     

“用户故事”在姿轨控软件需求分析中的应用

需求分析是软件开发过程中的重要环节.在国内卫星姿轨控软件设计过程中,需求分析阶段描述和定义用户需求的工作多数仍采用传统方法,过于关注软件的设计过程,而忽略了软件需要实现的功能,常常引发需求分析结果与任务方期望不一致的情况,影响开发进度.针对姿轨控软件的特点,在软件需求分析工作中引入敏捷开发所采用的＂用户故事（＂User Story）方法,可以高效清晰地描述和定义用户所需要的软件功能,提高任务方在需求分析阶段的参与程度,显著提高需求分析的准确性.     

一种基于GPS/磁强计/加速度计的组合导航/定姿方法

针对当前常用的导航、定姿方法存在的不足,提出了一种采用单天线GPS、磁强计和加速度计的组合导航、定姿方法.以常见的匀加速模型作为系统方程,以GPS输出的位置和速度作为观测量,设计了卡尔曼滤波器,获得更精确的载体速度、位置和加速度信息.在获得加速度估值之后,根据地磁场和载体比力在载体坐标系和导航坐标系的投影关系构造姿态矩...     

Stability-based SDRE controller for spacecraft momentum management

Momentum management of spacecraft aims to avoid the angular momentum accumulation of control momentum gyros through real-time attitude adjustment. An attitude control/momentum management controller based on state-dependent Riccati equation is developed for attitude-stabilized spacecraft. The governing equations of the system are formulated as three-axis coupled with full moment of inertia, which fully capture the nonlinearity of the system and are valid for systems with significant products of inertia or strong pitch to roll/yaw coupling. The state-dependent Riccati equation algorithm brings the nonlinear system to a linear structure having state dependent coefficients matrices and minimizing a quadratic-like performance index. The system equations are nondimensionalized, which avoid numerical problems at the same time make the weighting matrix more predictable. To guarantee closed-loop system stability, the state-dependent Riccati equation algorithm is also modified based on pole placement technique. The state-dependent Riccati equation is online calculated through the computational-efficient θ-D technique which reaches a tradeoff between control optimality and computation load. The dynamic characteristics of the system at torque equilibrium attitude are analyzed. Constraints on moment of inertia for successful momentum management are provided. Simulations demonstrate the excellent performance of the controller.     

Integrated orbit and attitude hardware-in-the-loop simulations for autonomous satellite formation flying

Development and experiment of an integrated orbit and attitude hardware-in-the-loop (HIL) simulator for autonomous satellite formation flying are presented. The integrated simulator system consists of an orbit HIL simulator for orbit determination and control, and an attitude HIL simulator for attitude determination and control. The integrated simulator involves four processes (orbit determination, orbit control, attitude determination, and attitude control), which interact with each other in the same way as actual flight processes do. Orbit determination is conducted by a relative navigation algorithm using double-difference GPS measurements based on the extended Kalman filter (EKF). Orbit control is performed by a state-dependent Riccati equation (SDRE) technique that is utilized as a nonlinear controller for the formation control problem. Attitude is determined from an attitude heading reference system (AHRS) sensor, and a proportional-derivative (PD) feedback controller is used to control the attitude HIL simulator using three momentum wheel assemblies. Integrated orbit and attitude simulations are performed for a formation reconfiguration scenario. By performing the four processes adequately, the desired formation reconfiguration from a baseline of 500–1000 m was achieved with meter-level position error and millimeter-level relative position navigation. This HIL simulation demonstrates the performance of the integrated HIL simulator and the feasibility of the applied algorithms in a real-time environment. Furthermore, the integrated HIL simulator system developed in the current study can be used as a ground-based testing environment to reproduce possible actual satellite formation operations.     

卫星姿态系统执行器故障的自适应控制设计

针对带冗余执行器的卫星姿态控制系统,考虑部分执行器发生未知故障(故障模式、大小、时间均未知)的情况,结合Backstepping方法设计了自适应容错控制器,使得当一个甚至多个飞轮出现未知故障时,系统能调整正常执行器的输入,补偿故障执行器的影响,保证系统闭环稳定及输出信号对参考输出量的渐近跟踪.对该算法进行仿真验证,得到了较理想的控制效果.     

基于简化误差修正的卫星姿态确定算法

针对典型的星敏感器/陀螺姿态卫星确定算法运算复杂这一问题,提出了一种基于简化误差修正的星敏感器/陀螺卫星姿态确定算法.通过对陀螺角速度进行简化修正,减少了滤波器的状态变量,降低滤波器的复杂性.仿真结果表明：该算法在保证姿态确定精度的条件下,能够减少运算量,提高算法的实时性.     

"M"型轨迹的新概念飞航导弹

基于各种新概念飞行器及弹道轨迹的特点,提出了一种"M"弹道轨迹的新概念导弹,并针对某型导弹设计了俯仰姿态控制系统,对该轨迹进行了纵向运动的全弹道仿真.仿真结果表明"M"型弹道轨迹完全可行,并且能大大节省能量.     

直升机内回路姿态模糊控制

 主要研究了直升机内回路的姿态控制技术, 将专家知识和训练数据相结合产生直升机的内回路模糊姿态控制器。由于模糊控制所固有的特点, 以及直升机的飞行状态多变, 模糊姿态控制器无法对直升机进行精确控制, 提出了利用另一个在线自适应模糊系统来补偿控制误差的方法。自适应模糊控制器的自适应学习算法通过李亚普诺夫稳定性分析得到, 从而也保证了整个系统的稳定性。仿真算例证明了本方法的有效性。关键词: 直升机; 姿态控制; 模糊控制; 自适应控制; 仿真