Variable structure control for satellite attitude stabilization in elliptic orbits using solar radiation pressure

The paper proposes the use of solar radiation pressure for satellite attitude control in elliptic orbits based on variable structure control. The system comprises of a satellite with two-oppositely placed solar flaps. Sliding mode control and terminal sliding mode control techniques have been adopted to develop nonlinear control laws for suitably rotating the control solar flaps to neutralize the adverse effect of eccentricity normally responsible for a considerable deterioration in the attitude control performance. The detailed numerical simulation of the governing nonlinear equation of the motion including the effects of various system parameters on the controller performance, establishes the feasibility of the proposed control strategy. The proposed controller is found to be robust against parameter uncertainties and external disturbances and thereby, the control strategy presented in the paper may be applicable to future satellite missions.     

模糊神经网络控制器在卫星姿态控制系统中的应用

现代卫星的姿轨控制面临着挠性附件对本体姿态的耦合作用。本文将卫星太阳帆板挠性结构对本体姿态的影响增广进系统方程 ,在PID控制器控制刚体卫星的基础上 ,设计了模糊神经网络控制器 ,采用反向传播和最小方差估计的学习方法进行模糊规则的学习 ,仿真表明 ,模糊神经网络特有的学习和处理定性与定量知识的优点 ,将使卫星姿态在参数变化与外部干扰情况下具有较好的姿态稳定度与精度。     

An attitude control approach for compensation of satellite drift in elliptic synchronous orbits

This paper explores the possibility of developing a new attitude control method for satellites in elliptic, 24-hour orbits, in order to compensate for the effect of longitudinal periodic drift relative to the ground station. A simple solar attitude control technique has been proposed for achieving the fixed apparent satellite orientation with respect to the ground segment of the space mission. The proposed control approach appears to be quite attractive for various satellite applications as it can substantially overcome the problems created by the continual periodic angular drift as well as undesirable pitching excitation in the elliptic orbits. Generalizing the analytically developed open-loop control policy results in a significant improvement of the controller performance.     

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.     

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.     

以VSCMG为执行器的航天器姿态机动自适应动态滑模控制

针对刚体航天器姿态机动控制问题,结合变速控制力矩陀螺(VSCMG)执行器的特性,提出一种自适应动态滑模控制律,提高了姿态机动控制的扰动抑制能力和鲁棒性。此控制律采用自适应方法对扰动力矩进行估计,通过给出控制力矩变化率并对其积分得到控制力矩,以此削弱切换控制的抖振对控制力矩时间连续性的影响,从而改善系统的动态性能。仿真分析显示该控制律能够在扰动力矩作用下实现刚体航天器的快速姿态机动,并且有效减弱了滑模控制的抖振现象。     

帆板转动时卫星姿态的非线性控制

当帆板转动时，卫星姿态因系统质量特性的改变和帆板驱动力矩的作用而发生扰动，本文采用一种具有鲁棒性的非线性控制方法，实现了高精度的卫星姿态控制。     

液体远地点发动机工作期间卫星姿态的自适应控制

本文将全系数自适应控制方法用于带有液体晃动和挠性太阳帆板的三轴稳定地球同步轨道卫星在远地点发动机工作期间的姿态自适应控制。仿真结果表明,用全系数自适应控制方法设计的控制器,其动态性能好,对参数变化的适应性强,抗干扰能力强,鲁棒性好,性能指标完全满足设计要求。     

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。     

帆板驱动影响下的卫星姿态高精度高稳定度控制

受步进电机驱动作用,太阳帆板对日定向时卫星姿态受到影响。本文针对帆板驱动不平稳引起的同卫星姿态耦合干扰,提出了一种卫星姿态稳定和太阳帆板对日定向的复合控制方法。卫星姿态稳定采用自抗扰控制器,以估计补偿由帆板驱动和系统不确定性引起的干扰,并在此基础上,设计了步进电机自适应电流补偿驱动器,以克服帆板驱动机构摩擦力矩和谐波力矩影响。仿真结果表明,该方法能大大提高卫星姿态控制精度和稳定度,同时还改善了帆板对日定向的精度。
     

Inertially fixed pitch stabilization of satellites by solar radiation pressure

Utilization of solar radiation pressure to stabilize the pitch attitude of an unsymmetrical satellite along an inertially-fixed orientation is investigated. A controller employing two rotatable highly reflective control surfaces is proposed and a control strategy involving both nominal and feedback controls is synthesized. Accounting for the apparent annual motion of the Sun, the validity of the concept throughout the year is established through a stability analysis of the system. The influence of the Earth's shadow on the controller performance is also analyzed. The speed of response as well as the pointing accuracy capabilities of the system appear to be quite acceptable for long-life scientific missions.     

某多挠性体卫星姿态的模糊神经网络控制设计

为改善多挠性体卫星的姿态控制系统,研究了一种基于模糊神经网络的控制器设计.根据某卫星的姿态和挠性动力学模型,给出了模糊神经网络控制器(FNNC)结构及其简化的带动量学习算法.仿真结果表明:FNNC能较好地适应卫星本体参数变化,对外界干扰的抑制能力良好,可满足高精度、高稳定度卫星的姿控要求.     

面向非沿迹成像的姿态跟踪扩展观测器滑模控制

针对地面兴趣点不沿星下点轨迹的动态非沿轨迹成像问题,设计一种结合扩展状态观测器的非奇异快速终端滑模控制器。首先根据非沿轨迹成像模型的需求推导卫星姿态参考轨迹。其次,根据由误差四元数描述的跟踪误差运动模型设计了非奇异快速终端滑模控制律。考虑到干扰抑制,引入了扩展状态观测器来观测系统的总扰动,从而降低滑模控制律中的切换增益,削弱系统抖振。然后再用模糊自适应系统对切换项进行在线逼近,柔化控制信号,进一步减振。最后,对具有干扰和参数不确定的姿态控制系统进行了数值仿真,结果表明该方法收敛速度快,控制精度高。     

一种模型独立自适应姿态跟踪滑模控制器

以一种能够自适应变化的伪转动惯量,基于Lyapunov稳定定理,推导出一种模型独立的航天器自适应姿态跟踪控制律。理论和数值仿真结果表明,与一般情况下需确知模型参数确定性部分的滑模姿态控制律相比,该控制律能够在不依赖于模型参数确定性部分的情况下良好地实现姿态跟踪,并对模型误差的不确定性和外干扰力矩具有一定的鲁棒性。     

再入飞行器自适应最优姿态控制

针对再入飞行器姿态控制问题，应用自适应动态规划（ADP）理论设计了姿态控制器。将再入飞行器的姿态控制建模为非线性系统的最优控制问题，提出单网络积分型强化学习（SNIRL）算法进行求解，该算法简化了积分型强化学习（IRL）算法在迭代计算中的执行-评价双网络结构，只需要采用评价网络估计值函数就可以求得最优控制律，其收敛性得到了理论证明。基于SNIRL算法设计了自适应最优控制器，并证明了闭环系统的稳定性。通过数值仿真校验了SNIRL算法比IRL算法计算效率更高，收敛速度更快，并校验了自适应最优姿态控制器的有效性 。     

含不确定性的绳系卫星姿态的鲁棒最优控制

针对绳长变化的旋转二体绳系卫星姿态跟踪控制问题,提出了一种分布式鲁棒最优控制方法。首先针对单体绳系卫星姿态模型,在假设模型精确和不存在干扰的条件下,设计基于HamiltonJacobiBellman方程的最优控制器;进一步考虑到实际系统存在参数不确定性和干扰,采用自适应方法和鲁棒误差积分方法隐式学习参数不确定性和有界干扰,与最优控制器结合设计鲁棒最优控制器,并应用Lyapunov稳定性定理证明其闭环系统的渐近稳定性。其次,根据绳系卫星系统的运动同步性,将单体绳系卫星姿态控制器设计扩展至二体绳系卫星系统,设计二体绳系卫星姿态系统的分布式鲁棒最优控制器。最后在Matlab/Simulink平台上进行仿真验证,结果表明了所设计控制器的可行性与有效性。     

基于鲁棒控制方法的卫星姿态控制

针对卫星姿态控制系统 ,建立了简化的线性数学模型 ,利用鲁棒控制方法设计了卫星姿态控制律 ,由于在设计中考虑了建模过程中的简化而带来的不确定性 ,因而基于线性模型所设计的控制律能够应用于非线性卫星姿态系统的控制     

绳系太阳能发电卫星姿态机动的主动振动控制

针对绳系太阳能发电卫星大角度回转机动时太阳能板的振动抑制问题,提出了主姿态控制和基于绳中张力的主动振动控制技术相结合的复合控制方法。建立了绳系太阳能发电卫星系统的动力学方程,并基于任务函数控制算法设计了主控制器保证卫星姿态的渐近稳定和挠性结构振动的衰减性;考虑到绳的非线性特性,基于任务函数控制算法设计了绳系卫星系统的主动振动抑制辅助控制器来抑制挠性结构的振动。设计的同时证明了系统的稳定性。将该方法应用于绳系卫星的大角度单轴回转机动的仿真研究,结果表明:该方法不仅能够使绳系卫星完成姿态机动,而且能够有效地抑制太阳能板的振动。     

大挠性多体卫星的自抗扰姿态控制系统设计

研究了最近提出的非线性自抗扰控制器 (ADRC)在大挠性多体卫星姿态控制中的应用问题。提出了一种双闭环自抗扰姿态控制器 (ADRAC) ,并从鲁棒性、干扰抑制、动静态性能指标和振动抑制等方面与使用于某挠性卫星的传统PID控制器进行了比较。在考虑了反作用轮和敏感器的实际非线性和敏感器噪声的影响情况下进行了仿真 ,结果表明 ,双闭环自抗扰姿态控制器各方面性能均优于传统的PID。本文提出的自抗扰姿态控制器 ,对实现挠性多体卫星的高精度高稳定度姿态控制 ,具有实际的应用价值     

小卫星的鲁棒自适应姿态控制

对于中低轨道的小卫星而言，设计能克服参数不确定性及非参数不确定性影响的鲁棒自适应控制器具有重要的工程意义和理论价值。考虑存在参数不确定性及非参数不确定性，分析了小卫星的姿态动力学及运动学方程，设计出了一种鲁棒自适应控制器，证明了该控制器可以保证控制系统全局一致最终有界稳定。仿真结果验证了该控制器的有效性。