自主交会对接若干问题

自主交会对接是交会对接技术的发展趋势。本文首先介绍了国际上自主交会对接的研究概况，然后研究了假设目标航天器为刚体，运动在圆轨道或近圆轨道上，追踪航天器与目标航天器在近距离范围内实现自主交会对接的若干问题，即信息自主获取的测量技术，智能自主的控制技术和保证飞行状态及避免碰撞的人工智能技术。为实现自主交会对接，智能控制是非常重要的手段。     

电激励因素影响合成射流的实验研究

设计了合成射流双膜激励器及实验测试系统。采用热线风速仪对激励器出口下游不同点的速度进行测量并分析合成射流的发展演化，对电激励因素即激励电压幅值、频率及信号波形对合成射流的影响进行试验和分析，对激励器在不同激励频率下启动工作时合成射流的响应及建立时间进行了考察。     

网络化飞行器执行机构故障自适应容错控制

针对存在随机短时延和外部干扰的网络化飞行器执行机构故障问题,提出了一种自适应容错控制方法。首先利用扩张状态观测器(Extended State Observer, ESO)对系统不确定性进行估计,并构建了自抗扰控制器对不确定性进行补偿。在此基础上,设计了一种基于跟踪误差的自适应容错控制方法。当执行机构发生未知故障后执行机构指令能自适应逼近设计值,使得重构的控制系统精确跟踪参考模型。最后利用Lyapunov函数方法证明了闭环控制系统的有界稳定。数值仿真校验了所提方法的有效性。     

基于增广观测器的非线性系统执行器故障诊断

针对一类满足李普希茨条件的非线性系统,提出了一种新的执行器故障诊断方法。将执行器故障作为增广状态向量的一部分构造一个增广系统,然后利用线性矩阵不等式方法设计一个增广状态观测器,能够同时获得原系统的状态和执行器故障的渐近估计。利用李亚普诺夫理论分析了增广状态观测器的稳定性和收敛性。最后,将所提出的方法用于卫星姿态控制系统执行器的故障诊断,仿真结果验证了该方法的有效性。     

Onboard actuator model-based Incremental Nonlinear Dynamic Inversion for quadrotor attitude control: Method and application

This paper addresses the robust attitude control problem for quadrotors subject to model mismatch and disturbances. A dynamic inversion based attitude control scheme is proposed, which consists of an outer loop attitude controller and an inner loop angular acceleration controller. The attitude controller is designed based on the Nonlinear Dynamic Inversion (NDI) to precisely linearize the nonlinear dynamics between the angular acceleration and the attitude. An onboard actuator model-based Incremental Nonlinear Dynamic Inversion (INDI) controller is designed in the angular acceleration control loop to improve the robustness against the model mismatch and disturbances. Meanwhile, the onboard actuator model with a modified structure eliminates the oscillation phenomenon when the sampling rate of the controller is higher than that of the actuator. Numerical simulations and flight tests demonstrate the effectiveness and robustness of the proposed controller in comparison with the PID controller.     

考虑执行机构故障的导弹姿态控制系统的集成容错控制

研究了一类发动机十字型布局的导弹姿态控制系统的容错控制问题,提出了一种考虑执行机构故障的导弹姿态控制系统集成容错控制方法。该方法针对执行机构的恒增益变化故障和卡死故障,首先提出了集成容错控制的总体策略,然后分别基于线性矩阵不等式方法和故障补偿思想,给出了在圆盘极点指标和H∞指标两个相容指标约束下的状态反馈满意容错控制器和故障补偿器的设计方法。最后在Matlab/Simulink环境下将该方法应用于导弹姿态控制系统进行仿真实验,结果表明了该方法的有效性和可行性。     

Aeroelastic scaling laws for gust load alleviation control system

Gust load alleviation (GLA) tests are widely conducted to study the effectiveness of the control laws and methods. The physical parameters of models in these tests are aeroelastic scaled, while the scaling of GLA control system is always unreached. This paper concentrates on studying the scaling laws of GLA control system. Through theoretical demonstration, the scaling criterion of a classical PID control system has been come up and a scaling methodology is provided and veri-fied. By adopting the scaling laws in this paper, gust response of the scaled model could be directly related to the full-scale aircraft theoretically under both open-loop and closed-loop conditions. Also, the influences of different scaling choices of an important non-dimensional parameter, the Froude number, have been studied in this paper. Furthermore for practical application, a compen-sating method is given when the theoretical scaled actuators or sensors cannot be obtained. Also, the scaling laws of some non-linear elements in control system such as the rate and amplitude sat-urations in actuator have been studied and examined by a numerical simulation.     

飞机起落架作动筒检测试验台的设计原理

作动筒作为飞机起落架的核心部件,其安全性检测对现代飞机具有重要的意义.目前,国内的作动筒检测方式非常不完善,主要以人工检测为主,检测精度较低.针对该问题,设计一种自动化、高精度的作动筒检测试验台,并对其工作原理、流程以及应用前景进行简要的介绍.     

A two-stage approach for managing actuators redundancy and its application to fault tolerant flight control

In safety-critical systems such as transportation aircraft, redundancy of actuators is introduced to improve fault tolerance. How to make the best use of remaining actuators to allow the system to continue achieving a desired operation in the presence of some actuators failures is the main subject of this paper. Considering that many dynamical systems, including flight dynamics of a transportation aircraft, can be expressed as an input affine nonlinear system, a new state representation is adopted here where the output dynamics are related with virtual inputs associated with the intended operation. This representation, as well as the distribution matrix associated with the effectiveness of the remaining operational actuators, allows us to define different levels of fault tolerant governability with respect to actuators’ failures. Then, a two-stage control approach is developed, leading first to the inversion of the output dynamics to get nominal values for the virtual inputs and then to the solution of a linear quadratic(LQ) problem to compute the solicitation of each operational actuator. The proposed approach is applied to the control of a transportation aircraft which performs a stabilized roll maneuver while a partial failure appears. Two fault scenarios are considered and the resulting performance of the proposed approach is displayed and discussed.     

Robust attitude coordinated control for spacecraft formation with communication delays

In this paper,attitude coordinated tracking control algorithms for multiple spacecraft formation are investigated with consideration of parametric uncertainties,external disturbances,communication delays and actuator saturation.Initially,a sliding mode delay-dependent attitude coordinated controller is proposed under bounded external disturbances.However,neither inertia uncertainty nor actuator constraint has been taken into account.Then,a robust saturated delay dependent attitude coordinated control law is further derived,where uncertainties and external disturbances are handled by Chebyshev neural networks (CNN).In addition,command filter technique is introduced to facilitate the backstepping design procedure,through which actuator saturation problem is solved.Thus the spacecraft in the formation are able to track the reference attitude trajectory even in the presence of time-varying communication delays.Rigorous analysis is presented by using Lyapunov-Krasovskii approach to demonstrate the stability of the closed-loop system under both control algorithms.Finally,the numerical examples are carried out to illustrate the efficiency of the theoretical results.