采用单框架控制力矩陀螺群的卫星侧摆机动控制研究

研究使用单框架控制力矩陀螺群 (SGCMGs)进行卫星姿态侧摆机动控制。研究频繁机动情况下由五棱锥构形和金字塔构形陀螺群进行侧摆机动控制的可行性 ,并探讨陀螺群构形奇异的避免问题。针对不同的陀螺群构形设计了不同的控制律 ,并比较两种构形的控制特性的异同。仿真结果验证了使用SGCMGs实现侧摆机动控制的有效性。     

Maneuver planning of a rigid spacecraft with two skew control moment gyros

The attitude maneuver planning of a rigid spacecraft using two skew single-gimbal control moment gyros (CMGs) is investigated. First, two types of restrictions are enforced on the gimbal motions of two skew CMGs, with each restriction yielding continuous control torque along a principal axis of the spacecraft. Then, it is proved that any axis fixed to the spacecraft can be pointed along an arbitrary inertial direction by at most two sequent rotations around the two actuated axes. Given this fact, a two-step eigenaxis rotation strategy, executing by the two single-axis torques respectively, is designed to point a given body-fixed axis along a desired direction. Furthermore, a three-step eigenaxis rotation strategy is constructed to achieve an arbitrary rest-to-rest attitude maneuver. The rotation angles required for the single-axis pointing and arbitrary attitude maneuver schemes are all analytically solved. Numerical examples are presented to demonstrate the effectiveness of the proposed algorithms.     

轮控小卫星姿态大角度机动递阶饱和控制器设计

针对采用反作用飞轮的小卫星姿态大角度机动控制，在反作用轮输出力矩受限、速率饱和的约束条件下，采用递阶饱和方法，即限制卫星每次姿态机动的最大偏差，对姿态偏差进行逐次消除。在毋需获知最优机动轨迹规划的情况下，可用于卫星任意时刻的姿态捕获和机动控制。数学仿真结果表明，本文设计的控制算．去能够实现快速姿态机动任务，具有良好的鲁棒性。     

一种改进的SGCMGs奇异鲁棒伪逆操纵律算法

以单框架控制力矩陀螺（SGCMG）为卫星动量交换机构,基于建立的姿态控制系统与SGCMG系统的动力学模型,设计零动量卫星的PD（比例微分）解耦姿态控制律。为逃避奇异,提出了一种改进的单框架控制力矩陀螺群（SGCMGs）奇异鲁棒伪逆操纵律算法。某航天器姿态控制仿真结果表明：改进算法可避免奇异,算法有效性得以验证。     

三轴稳定通信卫星在地球搜索模式下的陀螺标定

本文介绍三轴稳定通信卫星在转移轨道远地点点火前，在地球搜索模式下的陀螺标定方法和计算公式。此种陀螺标定需进行两次姿态机动，利用太阳敏感器和速率积分陀螺遥测数据标定陀螺的常值漂移。     

使用混合执行机构的快速机动卫星力矩分配算法

针对单框架控制力矩陀螺群（SGCMGs）存在奇异和单框架控制力矩陀螺（SGCMG）存在框架转速死区的问题,研究了SGCMG与飞轮联合作为执行机构的控制力矩分配算法,以SGCMG功耗、飞轮功耗和飞轮角动量的二次型加权矩阵求和为性能指标,提出了一种形式简洁的混合执行机构力矩分配算法,通过分析,证明该分配算法能够有效的避免SGCMGs的奇异;设计了一种SGCMG功耗加权矩阵的调节策略,解决了SGCMG陷入转速死区的问题,设计了一种飞轮角动量加权矩阵的调节策略,通过对加权矩阵的实时调节实现了对飞轮角动量的管理,解决了飞轮转速的饱和与过零问题。数学仿真结果验证了该力矩分配算法的有效性。     

Attitude controller design for orbital target tracking of geostationary satellite under avoidance constraint

A coordinated attitude control problem is addressed for which a geostationary satellite should maintain communication with a ground station while simultaneously tracking space objects. The coordinated attitude control discussed in this study is related to the attitude maneuvers of a tracking satellite and to the orbital motion of targets placed in orbits of lower altitudes. Modified Rodrigues parameters are employed to avoid singularities even in the presence of large attitude maneuvers. The initial attitude error is calculated based upon an arbitrary initial configuration for the target tracking, so that a sequential tracking from one to another target can be achieved easily. Additionally, avoidance maneuvers aimed at protecting sensitive onboard sensors from the Sun and the Moon are designed using the so-called navigation function. When the avoidance areas are on the transient path due to the coordinated attitude maneuver command, the maneuver is performed with no violation against the given constraint areas by adopting the navigation function.     

三轴稳定遥感卫星姿控系统故障情况下的系统重构

论述三轴对地稳定遥感卫星姿控系统中部分轮子或部分陀螺故障情况下的姿控系统重构。文中论述了只在俯仰通道有一偏置动量轮正常工作，而滚动和偏航通道轮子故障条件下的系统重构。另外还论述了偏航陀螺故障，姿控系统其它部件正常情况下，控制系统采用Whecon原理与PIM控制相结合的设计。以上两种系统重构拟用于实际系统中，经过数学仿真验证，姿控系统在故障情况下能够完成基本任务。     

具有SGCMG系统的挠性卫星姿态机动控制及验证

针对挠性卫星在轨姿态快速机动的需求，开展了星体姿态机动控制方法及控制实现研究。基于建立的挠性卫星姿态跟踪控制误差方程，给出了PD控制与补偿控制相结合的姿态跟踪控制器形式；考虑系统实现的时延影响，利用经典频率分析方法选择了兼顾系统稳定性及宽带控制的控制参数；在控制具体实现中，采用一种新型的基于力矩矢量调节奇异规避操纵策略，克服常规鲁棒奇异规避操纵存在的框架“锁死”现象，在解决奇异规避的同时避免激发挠性振动。所提出方法的有效性通过了在轨验证。     

空间飞行器大角度机动递阶饱和控制律设计

针对以飞轮为执行机构的空间飞行器进行姿态大角度机动递阶饱和控制。在初始状念任意，反作用轮输出力矩受限、速率饱和约束条件下，提出递阶饱和的变结构机动策略，即针对飞行器的运动学模型，利用飞行器的误差四元数和角速度，通过绕瞬时欧拉轴旋转，引入误差凹元数限幅器，对姿态偏差进行逐次消除，提出了不需事先规划轨迹的绕欧拉轴逐次逼近控制算法。并且引入模糊推理规则来改进递阶饱和变结构控制设计，使得系统轨迹既能快速趋近滑动面又能降低抖振，有效减弱了一般变结构控制律中抖振问题，从而提高了变结构控制律的品质。     

On orbit control using gravity gradient effects

Possibility of orbit control using gravity gradient (GG) effects without any mass expulsion is discussed. For simplicity, a dumb-bell type satellite and circular orbits are mainly considered. It is shown that the GG effects can be applied to convert attitude torques into orbital torques and vice versa. In central gravitational force fields, maximum orbital torques or thrusts are available from the GG force when roll or pitch angle is $\text{±}\text{π}\text{4}$ provided that the attitude angle is null when the dumb-bell axis coincides with the local vertical. Such external torques as geomagnetic or solar wind pressure can be utilized to maintain the $\text{±}\text{π}\text{4}$ attitude, then the orbital torques are available forever. In non-central gravitational fields, without any external torque, the orbital radii of circular orbits can be increased by controlling the satellite attitude using electric energy. The use of the Earth's oblateness effects and the exterior Lunar potential is discussed.     

利用反作用飞轮阵实现飞行器大角度姿态机动的非线性快速控制

本文首先给出了采用姿态角速度和四元数矢量部分表示的姿态动力学模型。然后,构造了一个可逆的全局非线性坐标变换,使得非线性姿态动力学模型与一个具有可控标准形的线性系统等价。进一步的设计了反作用飞轮电机力矩的快速控制规律。给出了机动时间和系统状态的简单计算公式。最后,文中还介绍了数字仿真实例和结果。     

基于变惯量反作用飞轮的小卫星大角度姿态机动控制研究

研究以变惯量反作用飞轮作为执行机构的小卫星的大角度姿态机动控制问题。变惯量反作用飞轮是一种新型的动量交换装置,不仅可以通过改变飞轮转速输出力矩,还可以通过改变其转动惯量实现大范围的力矩输出。文中建立了带有变惯量反作用飞轮的星体姿态动力学方程,设计了姿态控制律和飞轮的操纵律。仿真结果表明,与一般反作用飞轮相比,当小卫星大角度机动时变惯量飞轮的转速更不容易饱和,且力矩的输出范围变宽,可以同时满足小卫星高精度稳定和快速大角度姿态机动的双重要求。     

Attitude control schemes for the first recovery mission of India

This paper describes the attitude control schemes for the various phases such as acquisition, on-orbit, orbit maneuver, de-boost maneuvers and coast phases of the India's first recovery mission Space Capsule Recovery Experiment-I (SRE-1). During the on-orbit phase, the SRE was configured to point the negative roll axis to Sun. The attitude referencing of SRE-1 was based on dry tuned gyros with updates from the attitude determined using on-board Sun sensors and magnetometer. For attitude acquisition, attitude maneuvers and for providing the velocity corrections for de-orbiting operations; a set of eight thrusters grouped in functionally redundant blocks were used. The control scheme with thrusters was based on proportional derivative controller with a modulator. In order to ensure micro-gravity environment during the on-orbit payload operations a linear quadratic regulator (LQR) based control scheme was designed to drive an orthogonal configuration of magnetic torquers which in turn produced three-axis control torque with the interaction of Earth's magnetic field. Proportional derivative control scheme with modulator was designed to track the steering commands during the velocity reduction as well as during the coasting phase of the de-orbiting operations. A novel thruster failure detection, isolation and reconfiguration scheme implemented on-board for the de-orbiting phase is also discussed in this paper.     

探月卫星变轨时的姿态控制研究

基于伪速率调制器的原理,提出了利用脉宽调制器替代伪速率调制器 实现姿态控制的方法,并针对于三种不同干扰力矩,对探月飞行器变轨时的姿态 控制加以仿真。仿真结果表明,脉宽调制器在功能上可以代替伪速率调制器。     

基于前馈补偿的高精度卫星姿态控制

研究带有大型单翼太阳帆板的三轴稳定卫星在稳态运行期间姿态精确定向问题。计算了卫星运行空间的环境干扰力矩，分析了传统控制方法的局限性，并给出一种新的卫星姿态高精度动态补偿控制算法。推导了卫星的挠性动力学模型，在此基础上通过仿真比较了此方法和传统方法的实际效果。结果表明，该方法可以显著提高姿态控制的响应速度和精度。     

The results of flight tests of an attitude control system for the Chibis-M microsatellite

The attitude control system of the Chibis-M microsatellite is described. Results of flight experiments on damping the initial angular velocity (made using magnetorquers) are considered, as well as stabilization in the orbital referece frame, and orientation of solar arrays toward the Sun using reaction wheels. The operation of algorithms of satellite attitude determination on sunlit and shadow segments of the orbit is also under study. The general logic of operation of the attitude control system in automatic mode is presented and discussed.     

某卫星姿态角的确定和对测量部件的故障诊断

卫星三轴姿态的确定是对卫星进行姿态控制的基础,利用陀螺和红外敏感器互补的特性,并对测量所得到的数据进行处理,便可得到卫星姿态角的估计值。陀螺和红外地球敏感器是卫星姿态控制系统中关键的测量部件,两者的测量输出通过卫星运动学方程相关,有冗余关系,可以用于故障检测。本文对所设计的观测器进行了数值仿真,证实了其有效性,并直接利用所设计的观测器进行故障检测,首先得出陀螺和红外地球敏感器在各种故障下的输出残差曲线,然后分析陀螺和红外地球敏感器的不同故障对输出残差信号的不同影响,找出各种故障与不同输出残差的对应关系,从而确定发生故障的部件。     

非零初末角速度约束下的卫星实时姿态机动规划

针对存在初末角速度非零约束的卫星姿态机动任务,提出了一种基于旋转分解的实时解析规划算法。该方法通过将卫星三维旋转分解为多个绕固定轴的一维欧拉旋转,使非线性规划问题转换为多个一维空间上的线性规划问题,再将各个线性规划的结果通过四元数运算融合为最终的姿态机动规划结果。与过去针对此类问题经常采用的非线性规划方法相比,该规划算法可以通过解析的形式给出,因此不需要通过多次数值迭代得到可行解,运算量少,可以实时进行计算,适合实际在轨应用。