直连式三体绳系卫星姿态鲁棒最优跟踪控制

 针对存在参数不确定性以及外部有界干扰的直连式三体旋转绳系卫星系统姿态跟踪控制问题,提出了一种分布式鲁棒最优控制方法。该方法首先针对单体绳系卫星姿态模型,在不考虑参数不确定性和干扰的条件下,应用Hamilton-Jacobi-Bellman方程设计了最优控制器;接着,考虑到实际系统存在参数不确定性和干扰,采用自适应与鲁棒误差积分方法在线学习参数不确定性和有界干扰,与最优控制器结合设计了鲁棒最优控制器,使闭环系统满足了性能指标达到最小的要求,并应用Lyapunov稳定性定理证明了其闭环系统的渐近稳定性。进一步考虑到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直连式三体绳系卫星姿态系统,设计了分布式鲁棒最优控制器。最后在MATLAB/Simulink平台上进行了仿真,验证了方法的可行性与有效性,表明其具有潜在的应用前景。     

挠性航天器的退步直接自适应姿态跟踪控制

针对参数不确定的挠性航天器姿态跟踪控制问题,提出了一种退步直接自适应控制算法。首先验证了挠性航天器动力学子系统的近似严格正实性,并设计了具有理想控制性能的参考模型;然后对以姿态四元数描述的运动学子系统设计常系数输出反馈中间控制律,使航天器姿态四元数输出渐近跟踪参考模型输出;最后退一步,对具有参数不确定特性的动力学子系统,基于非线性直接自适应控制理论和Lyapunov稳定性理论,设计了退步直接自适应姿态跟踪控制器,并证明了闭环系统的稳定性。仿真结果表明,所提控制方法能有效抑制挠性附件的振动,对挠性航天器的控制是有效的。     

Yaw controller design of stratospheric airship based on phase plane method

Recently,stratospheric airships prefer to employ a vectored tail rotor or differential main propellers for the yaw control,rather than the control surfaces like common low-altitude airship.The load capacity of vectored mechanism and propellers are always limited by the weight and strength,which bring challenges for the attitude controller.In this paper,the yaw channel of airship dynamics is firstly rewritten as a simplified two-order dynamics equation and the dynamic characteristics is analyzed with a phase plane method.Analysis shows that when ignoring damping,the yaw control channel is available to the minimum principle of Pontryagin for optimal control,which can obtain a Bang–Bang controller.But under this controller,the control output could be bouncing around the theoretical switch curve due to the presence of disturbance and damping,which makes adverse effects for the servo structure.Considering the structure requirements of actuators,a phase plane method controller is employed,with a dead zone surrounded by several phase switch curve.Thus,the controller outputs are limited to finite values.Finally,through the numerical simulation and actual flight experiment,the method is proved to be effective.     

Feedback linearization and solar pressure satellite attitudecontrol

The question of large angle pitch attitude maneuver of satellites using solar radiation pressure is considered. For pitch axis maneuver, two highly reflective control surfaces are used to generate radiation moment. Based on dynamic feedback linearization, a nonlinear control law is derived for large pitch attitude control. In the closed-loop system, the response characteristics of the pitch angle are governed by a fourth-order linear differential equation. Robustness of control system is obtained by the integral error feedback. Simulation results are presented to show that in the closed-loop system, attitude control of the satellite is accomplished in spite of the parameter uncertainty in the system     

不确定性非线性系统的自适应输出反馈控制

研究了一种不确定性非线性系统的自适应输出反馈控制方法.首先引入伪控制信号使系统反馈线性化,然后设计一个线性动态补偿器和在线神经网络,自适应消除不确定性和建模所引起的误差.仿真结果表明,该控制方法能够消除系统的稳态误差,提高系统动态性能,并且具有较好的鲁棒性.     

Dynamics modeling and control of a transport aircraft for ultra-low altitude airdrop

The nonlinear aircraft model with heavy cargo moving inside is derived by using the separation body method, which can describe the influence of the moving cargo on the aircraft attitude and altitude accurately. Furthermore, the nonlinear system is decoupled and linearized through the input–output feedback linearization method. On this basis, an iterative quasi-sliding mode(SM)flight controller for speed and pitch angle control is proposed. At the first-level SM, a global dynamic switching function is introduced thus eliminating the reaching phase of the sliding motion.At the second-level SM, a nonlinear function with the property of ‘‘smaller errors correspond to bigger gains and bigger errors correspond to saturated gains' ' is designed to form an integral sliding manifold, and the overcompensation of the integral term to big errors is weakened. Lyapunovbased analysis shows that the controller with strong robustness can reject both constant and time-varying model uncertainties. The performance of the proposed control strategy is verified in a maximum load airdrop mission.     

Adaptive Integral-type Sliding Mode Control for Spacecraft Attitude Maneuvering Under Actuator Stuck Failures

A fault tolerant control (FTC) design technique against actuator stuck faults is investigated using integral-type sliding mode control (ISMC) with application to spacecraft attitude maneuvering control system. The principle of the proposed FTC scheme is to design an integral-type sliding mode attitude controller using on-line parameter adaptive updating law to compensate for the effects of stuck actuators. This adaptive law also provides both the estimates of the system parameters and external disturbances such that a prior knowledge of the spacecraft inertia or boundedness of disturbances is not required. Moreover, by including the integral feedback term, the designed controller can not only tolerate actuator stuck faults, but also compensate the disturbances with constant components. For the synthesis of controller, the fault time, patterns and values are unknown in advance, as motivated from a practical spacecraft control application. Complete stability and performance analysis are presented and illustrative simulation results of application to a spacecraft show that high precise attitude control with zero steady-error is successfully achieved using various scenarios of stuck failures in actuators.     

基于变结构控制器的敏捷卫星姿态机动方法

随着遥感卫星观测能力的逐步提升,对卫星敏捷机动能力提出了更高的要求。针对敏捷卫星大角度姿态机动问题,以6个单框架控制力矩陀螺(SGCMG)组成五棱锥构型的姿态控制系统执行机构,在构建敏捷卫星姿态运动数学模型以及设计SGCMG系统操纵律的基础上,对卫星绕Euler轴进行姿态机动的角轨迹进行规划,并设计了一种基于误差四元数与误差角速度的变结构控制器。仿真及在轨验证结果表明,该控制器能够完成规划轨迹的良好跟踪且具有较强的鲁棒性,研究成果对敏捷卫星姿态控制系统的设计具有重要的参考意义。     

基于BOWA小脑模型的高精度稳定 电动加载系统

 随着电动加载系统的不断发展,对控制精度、动态特性和稳定性提出了更高的要求,常规的小脑模型(CMAC)和PD控制相结合的复合控制策略难以满足加载指标要求。针对无人机舵机电动加载系统的控制需求,提出了一种基于平衡学习、最优权值和自适应学习率的新型小脑模型(BOWA-CMAC)复合控制策略,它在保留小脑模型算法正常学习过程的同时,避免了算法的过学习现象,保证了系统的稳定,同时提高了跟踪精度和动态特性。仿真和实验结果表明,BOWA-CMAC复合控制策略具有很强的鲁棒性,抑制了加载系统的多余力矩,保证了系统的稳定性,有效提高了系统的跟踪精度和动态特性,非常适合于实时控制。     

一种基于在线辨识和专家系统的飞行器智能姿态控制方法

针对未来战场形势对攻击型飞行器提出的大包线飞行、大不确定、主动容错控制问题,提出了一种基于在线辨识和专家系统的智能姿态控制方法。该方法通过在线估计飞行器的时域、频域关键参数,驱动专家系统实时计算并调整控制器参数;结合时域、频域辨识结果诊断、定位故障,实现故障隔离、控制策略调整。该方法综合了飞行器结构、气动试验数据和专家知识,通过在线辨识和估计丰富了专家系统推理计算所需信息,促进了专家系统的在线应用,是一种近期可实现的智能控制方法。仿真结果表明,采用该方法,姿态发散概率由无容错控制时的45%降低到容错控制时的0%,姿态控制任务完成率100%。     

航天器有限时间输出反馈姿态控制

研究在角速度不可测时航天器的有限时间姿态控制问题。基于有限时间控制技术,提出了由修正Rodrigues参数进行姿态描述的航天器输出反馈姿态控制算法。首先设计了单个航天器的输出反馈姿态控制器,在没有角速度反馈时也能够保证航天器姿态在有限时间内调节到期望姿态。之后,设计了无需绝对角速度和相对角速度信息的多航天器分布式输出反馈姿态控制器。使用Lyapunov理论和图论,对闭环系统全局有限时间稳定性进行了严格的证明。最后对提出的控制算法进行了数值仿真,其结果验证了所设计的航天器输出反馈控制算法的可行性和有效性。     

基于MRP的全局稳定的PID刚体姿态控制

针对刚性航天器姿态控制问题,建立了由修正Rodrigues参数(MRP)表示的混杂姿态模型,并基于此模型设计了一种具有迟滞特性的非线性比例-积分-微分(PID)切换控制器.该控制器包含一个对克里奥利力矩和期望机动力矩的前馈补偿项和一个用于消除轨迹跟踪误差的PID反馈项.通过一个特别的Lyapunov函数分析得到了全局渐...     

An Approach to Optimization of Terminal Rendezvous

The optimal solution is presented to a cooperative game which is described by a common quadratic cost functional subject to linear ordinary differential equation constraints. The optimal feedback controller is constructed for both players when all components of the state vector can be measured. For the case that only some components of the state vector are available, the optimal feedback controller is designed using a dynamic observer. As a specific application, the approach is used in determining the optimal feedback controllers for two satellites which are performing a rendezvous on a circular orbit. Simulation results are presented to illustrate the applicability of the approach.     

绕飞监测小卫星姿轨联合自适应控制研究

针对小卫星近距操作过程中轨道和姿态控制问题,建立了小卫星相对轨道和姿态的误差动力学模型。采用相对轨道和姿态联合控制策略,并考虑小卫星作业过程中质量和转动惯量的不确定性,设计了自适应输出反馈控制律,并证明了其稳定性。最后以对圆轨道目标星近距离环航为例,根据作业任务和姿态指向要求,设计了小卫星相对轨道和姿态的期望运动,应用所提出的控制策略及相应的控制律进行了数值仿真。结果表明,系统跟踪误差能够较快收敛,说明了控制策略的有效性。     

半捷联位标器稳定跟踪与弹体姿态一体化控制

半捷联位标器安装在弹体上,由于寄生回路的存在,使得位标器稳定跟踪控制回路和弹体姿态控制回路产生严重耦合,影响了位标器的稳定与跟踪。针对半捷联导引头稳定平台的稳定与跟踪问题,提出了一种半捷联位标器稳定跟踪控制与弹体姿态控制的一体化方法。基于反步控制原理设计了控制律,通过合理选择反馈增益可保证系统的稳定性与动态性能。最后对一体化设计与传统分离设计进行了仿真对比。仿真结果表明：考虑位标器稳定跟踪回路与导弹姿态回路耦合的一体化控制器,不仅能够保证弹体姿态控制系统快速响应,还可以提高位标器的稳定跟踪性能,并降低位标器跟踪不上高速目标的可能性。     

Line-of-sight pointing stability for "drifting" satellites

Explored here is the feasibility of a new attitude control approach for satellites in high altitude elliptic orbits, in order to compensate for the effect of longitudinal periodic drift relative to the ground station. A simple attitude control technique using tethers has been proposed for achieving the fixed apparent satellite orientation with respect to the ground segment of the space mission. Combining the proposed feedback tether length control law with the analytically developed open-loop control policy results in a significant improvement of the controller performance. To illustrate implementation of the proposed concept, the particular case of 24 h elliptic orbits has been considered. A high degree of satellite pointing along the drifting line-of-sight made possible even with modest tether lengths makes the concept particularly attractive.     

执行器故障的挠性航天器姿态滑模容错控制

针对挠性航天器执行器卡死与失效故障的姿态稳定控制问题,提出一种改进型滑模容错控制策略.与传统的滑模控制相比,该方法能削弱传统滑模控制中抖振现象对姿态控制精度的影响,且它采用自适应技术在线估计系统中的不确定参数,从而保证控制性能对外部干扰、不确定甚至时变转动惯量具有良好的鲁棒性.该控制器并不需要任何在线或离线的故障信息,...     

Super twisting controller for on-orbit servicing to non-cooperative target

A relative position and attitude coupled controller is proposed for rendezvous and docking between two docking ports located in different spacecraft. It is concerned with servicing to a tumbling non-cooperative target spacecraft in arbitrary orbit subjected to external disturbances.By considering both kinematic and dynamical coupled effects of relative rotation on relative translation, a coupled dynamic model is established to represent the relative motion of docking port on target spacecraft with respect to another on the service spacecraft. The spacecraft control is based on the second order sliding mode algorithm of super twisting(ST). It is schemed to manipulate the relative position and attitude synchronously. A formal proof of the finite time convergence property of the closed-loop system is derived theoretically by the second method of Lyapunov. Numerical simulations with the designed ST controller are presented to validate the analytic analysis by contrast with the twisting control algorithm. Simulation results demonstrate that the proposed relative position and attitude integrated controller is characterized by high precision, strong robustness and high reliability.     

鲁棒性固定反馈增益阵控制系统设计

讨论了一种鲁棒性控制器的设计方法。此法已在总能量控制系统(TECS)的设计中得到应用。本文基于根平面理论来讨论这一问题,从而避免了复杂的数学计算,仅利用几何作图或计算机辅助设计,使控制器成为满足一定带宽和超调要求的鲁棒控制器。