Coupled Dynamics and Integrated Control for Position and Attitude Motions of Spacecraft: A Survey

Inspired by the integrated guidance and control design for endo-atmospheric aircraft, the integrated position and attitude control of spacecraft has attracted increasing attention and gradually induced a wide variety of study results in last over two decades, fully incorporating control requirements and actuator characteristics of space missions. This paper presents a novel and comprehensive survey to the coupled position and attitude motions of spacecraft from the perspective of dynamics and control. To this end, a systematic analysis is firstly conducted in details to show the position and attitude mutual couplings of spacecraft. Particularly, in terms of the time discrepancy between spacecraft position and attitude motions, space missions can be categorized into two types: space proximity operation and space orbital maneuver. Based on this classification, the studies on the coupled dynamic modeling and the integrated control design for position and attitude motions of spacecraft are sequentially summarized and analyzed. On the one hand, various coupled position and dynamic formulations of spacecraft based on various mathematical tools are reviewed and compared from five aspects, including mission applicability, modeling simplicity, physical clearance, information matching and expansibility. On the other hand, the development of the integrated position and attitude control of spacecraft is analyzed for two space missions, and especially, five distinctive development trends are captured for space operation missions. Finally, insightful prospects on future development of the integrated position and attitude control technology of spacecraft are proposed, pointing out current primary technical issues and possible feasible solutions.

     

基于自适应显式互补滤波的姿态解算方法

显式互补滤波(ECF,explicit complementary filter)原理简单、计算量小,被广泛应用于低成本的姿态检测系统中.针对显式互补滤波中PI参数只能试凑的问题,给出了其PI参数设计规律及其离散化形式,并提出了自适应显式互补滤波(AECF,adaptive explicit complementary filter)算法.该算法根据加速计的输出,判断载体的运动情况,实时调整PI参数,从而提高姿态估计的精度.实验测试表明,自适应显式互补滤波的静态和动态性能均优于固定增益的显式互补滤波.     

基于不变扩展卡尔曼滤波的无人机姿态估计

为解决四旋翼无人机姿态估计问题,提出了一种不变扩展卡尔曼滤波(Invariant Extended Kalman Filter, InEKF)算法,用于同时估计四旋翼的姿态和惯性测量单元(Inertial Measurement Unit, IMU)的陀螺仪偏差。利用李群理论和不变观测器设计方法,将算法表述为一个连续时间随机非线性滤波器,其状态空间由直积矩阵李群SO(3)×R³给出,SO(3)中的估计值由IMU对重力矢量和地球磁场向量测量值加以修正。为在无人机上实现该算法,将状态和协方差传播方程离散化。最后,所提滤波算法相对于现有算法的性能优势通过仿真实验得到了验证。     

Robust Adaptive Attitude Control for Non-rigid Spacecraft With Quantized Control Input

In this paper,an adaptive backstepping control scheme is proposed for attitude tracking of non-rigid spacecraft in the presence of input quantization,inertial uncertainty and external disturbance.TThe control signal for each actuator is quantized by sector-bounded quantizers,including the logarithmic quantizer and the hysteresis quantizer.By describing the impact of quantization in a new affine model and introducing a smooth function and a novel form of the control signal,the influence caused by input quantization and external disturbance is properly compensated for.Moreover,with the aid of the adaptive control technique,our approach can achieve attitude tracking without the explicit knowledge of inertial parameters.Unlike existing attitude control schemes for spacecraft,in this paper,the quantization parameters can be unknown,and the bounds of inertial parameters and disturbance are also not needed.In addition to proving the stability of the closed-loop system,the relationship between the control performance and design parameters is analyzed.Simulation results are presented to illustrate the effectiveness of the proposed scheme.     

粒子滤波器及其在卫星姿态估计中的应用

粒子退化和计算量较大是限制粒子滤波应用的主要问题,常规的重采样方法虽然可以缓解粒子退化,但却容易导致粒子枯竭,且计算量较大,因此本文提出了基于混沌摄动的均值逼近粒子滤波器。按权值大小将粒子分组后,用均值替换权值较小的粒子,可使粒子从低似然区向高似然区域逼近。用Kullback信息描述均值逼近产生的粒子分布与似然分布的差别,通过迭代发现Kullback信息是递减的,从而证明该算法是合理的。混沌摄动重采样算法,用类似载波的方法将具有全局遍历性的混沌变量引入,更增加了粒子的多样性。另外,将本算法应用于某型导弹的姿态估计问题中,仿真结果显示了新算法的有效性。     

基于Mahony滤波器和PID控制器的四旋翼飞行器姿态控制

四旋翼飞行器由于其简单的气动布局和复杂的动力学模型在控制领域引起了研究热潮,姿态估计与控制器设计一直是实现四旋翼飞行器稳定飞行的难点。为实现精确的四旋翼飞行器姿态估计,首先分析了IMU传感器示值组成和误差存在的原因,然后在方向余弦矩阵（DCM）和重正交化的基础上,具体给出了Mahony滤波器的实现流程。通过与扩展卡尔曼滤波器对比表明,该算法不仅能保证很高的姿态估计精度,而且计算时间小于扩展卡尔曼滤波器,有助于提高系统姿态估计的实时性。结合Mahony滤波后的姿态信息,采用嵌套PI-PID控制策略设计了控制器。最后,将姿态估计算法和控制算法应用到实验平台上,可以实现四旋翼飞行器悬停和角度跟踪功能。     

基于旋转矩阵KF的低成本MEMS姿态解算

针对低成本MEMS器件组合的姿态检测系统在运动加速度干扰下姿态估计精度较差等问题,提出了一种基于旋转矩阵卡尔曼滤波器(KF)的姿态解算方法.为了克服四元数法观测方程为非线性的缺点,该方法以旋转矩阵部分元素建立状态方程,并对量测加速度采用状态反馈估计的运动加速度进行补偿,减小了外部加速度的干扰,然后通过构造水平观测向量降低了计算复杂度,并给出了量测噪声协方差的推导.最后设计了卡尔曼滤波器对量测信息实现融合.动静态测试表明,该方法消除了累计误差,与无迹卡尔曼滤波(UKF)相比,提高了在运动加速度干扰下的姿态估计精度.     

定位定向系统中陀螺漂移误差估计

阐述了定位定向系统中的主要误差来源于陀螺漂移。建立陀螺漂移误差模型,分析了一阶自回归估计方法AR(1)和均值估计方法对漂移系数的估计。并通过反馈法测得陀螺的漂移系数,分别用一阶自回归估计方法和均值估计方法进行系数估计,并对估计效果进行比较。     

基于双目视觉的小型无人直升机位姿检测

无人直升机的位置与姿态检测是直升机自主飞行控制的基础。基于双目视觉原理,对直升机标志点进行检测并跟踪,利用基于顺序一致性的极线约束匹配方法,对检测到的多个标志点进行立体匹配,计算标志点三维坐标从而得到无人直升机的位置与姿态信息。设计一个基于双目视觉的小型无人直升机空间位姿测量托架,用于飞行控制模型及飞行控制算法的研究及验证。     

自适应Kalman滤波器及其应用

对于带未知噪声统计的单输出系统,本文提出了一种新的自适应Kalman滤波器.应用现代时间序列分析方法,基于ARMA新息模型的滑动平均(MA)参数的在线辨识,提出了稳态最优Kalman滤波器增益估计的一种新算法,比Mehra的算法简单.同时还提出了辨识滑动平均(MA)模型参数的一种新的自适应Kalman滤波算法.此外,给出了在雷达跟踪系统中的应用,且仿真结果说明了本文算法的有效性.     

一类非线性系统的自适应观测器

This paper investigates the means to design the ob- server for a class of nonlinear systems with Lipschitz conditions and unknown parameters.A new design approach of full-order state adaptive observer is proposed.The constructed observer could guarantee the error of state and the error of parameter estimation to asymptotically converge to zero.Furthermore,a numerical example is provided to verify the effectiveness of the observer.     

一类非线性系统的自适应观测器

研究一类非线性系统的观测器设计方法, 这类非线性系统满足 Lipschitz 条件且含有未知参数. 提出了全状态自适应观测器设计的新方法. 构造的观测器能保证状态估计误差及参数估计误差渐近收敛于零. 文中给出数值例验证了观测器的有效性.     

自适应控制系统设计的参数辨识途径

本文给出了一种关于自适应控制系统设计的方法,该方法的特点是把自适应控制律的设计问题转化为参数辨识问题,使非线性系统与多输入系统的处理变得较容易,而且使算法得到简化.     

Position Control of Robots by Nonlinearity Estimation and Compensation: Theory and Experiments

To improve the performance of position controllers of robots, a designapproach using the method of nonlinearity estimation and compensation ispresented. The controller designed has a similar structure to that of thelinear independent joint control. Nonlinearities in the robot dynamics areestimated by a state observer based on approximate linear models of thesystem, and then compensated by an appropriate feedback. The paper presentsthe theory how to design such a controller as well as the experimentalresults verifying its performance.     

基于自适应Kalman滤波的合成孔径声纳运动估计

合成孔径声纳姿态、位移测量系统一般包括：惯性测量单元（IMU），差分DGPS，声多普勒计程仪DVL，深度传感器等。通常情况下，惯性测量单元（IMU）必须与DVL或DGPS进行数据融合，才能减小发散现象，提高导航精度。合成孔径声纳基阵安装在拖体上，由水面舰船利用拖缆拖曳航行，其运动受海流扰动及拖船机动的影响，未知的机动输入估计及海流的估计是必须要考虑的，这是合成孔径声纳基阵运动估计的比较特殊的地方。传统的Kalman滤波器不能直接应用于合成孔径声纳姿态、运动估计。因此，采用自适应Kalman滤波算法来处理合成孔径声纳姿态、运动估计问题。数值仿真表明，该方法较好地解决了合成孔径声纳姿态、运动估计问题。     

基于光惯组合的风洞尾旋试验位姿参数测量方法

尾旋是飞机在失速时的一种复杂而危险的非正常飞行状态。研究飞机尾旋及改出特性的常用方法是开展立式风洞尾旋试验,其中测量方法是试验中的关键技术。在十几年的发展历程中,先后经历了双目立体视觉、编码标记图像识别和惯性航姿测量的技术改进,在不断提升的过程中对测量能力和数据质量也提出了更高要求,因此发展了一种基于光惯组合技术的尾旋6自由度数据测量方法,通过惯性系统测量三维姿态,光学系统测量空间位置信息。经过试验验证,该方法成功获取了尾旋模型6自由度数据,测量效率高,数据无缺失,根据模型运动轨迹在试验段截面投影可获得尾旋半径,增加了对于尾旋现象的认知维度。     

含有有色噪声的非线性分数阶系统自适应扩展卡尔曼滤波器

研究了含有未知参数的情况下，分别含有分数阶有色过程噪声和有色测量噪声的连续时间非线性分数阶系统状态估计问题.采用Grünwald-Letnikov （G-L）差分方法和1阶泰勒展开公式，对描述连续时间非线性分数阶系统的状态方程进行离散化和线性化.构造由状态量、未知参数和分数阶有色噪声的增广向量，设计自适应分数阶扩展卡尔曼滤波算法实现对有色噪声情况下的连续时间非线性分数阶系统的状态和参数的估计.最后，通过分析两个仿真实例，验证了提出算法的有效性.     

蒸馏稀释感知：适应性采样下的稀疏检测与估计

针对稀疏信号采样问题,提出一种改进的适应性采样方法,通过对原始信号的多次观测逐渐筛选出有用信号,从而提高观测的准确度.该方法增加了一个找回误判分量的机制,弥补了原始方法无法抑制漏检率的缺点.实验结果表明,所提出的方法有效地降低了判决器的漏检率,同时保持相同的计算复杂度,且在中等及较小信噪比条件下性能更优.     

多标记室内小型无人机定位与姿态估计方法

随着无人机（Unmanned Aerial Vehicle,UAV）小型化、轻便化的发展,因其价格低廉,以及在娱乐和服务领域的广泛使用的特点,使得如何实现一个便捷且易实现的自主飞行跟踪系统成为关注点。由于无人机在室内GPS信号弱,使得跟踪与姿态获取成为进一步室内无人机自主控制的重点与难点。与动辄几十万美元搭建的无人机跟踪系统相比,采用低成本单目摄像机的无人机跟踪系统具有更高的科研价值和更广泛的应用前景。针对目前流行的基于增强现实（Augmented Reality,AR）技术的ArUco标记算法和颜色空间域标记算法,设计了一种多标记的无人机跟踪系统。在无人机目标跟踪过程中比较两种方法,验证了两种方法非接触式深度传感器无人机跟踪和姿态估计的效果,并比较了两种方法对空间亮度与空间颜色复杂度的鲁棒性,以及不同跟踪距离下视频中无人机检出率与跟踪精度。实验结果表明,基于深度摄像机获得的无人机位置和姿态数据,无人机可以进行自主的PID控制飞行,且AR标记在复杂环境下无人机的检出率、跟踪实时性、姿态估计精度以及鲁棒性都优于颜色标记,为之后室内无人机在非接触式传感的控制、路径规划、自主规避等进一步实验研究提供了无人机的位置和姿态数据。     

ADRC Law of Spacecraft Rendezvous and Docking in Final Approach Phase

This article addresses the high-precision coordinated control problem of spacecraft autonomous rendezvous and docking, which couple the relative position and attitude in the final approach phase. The coupled dynamics equations of the tracking-target spacecrafts is derived by using dual quaternions. Then, a cascade Active Disturbance Rejection Controller is proposed, by which the extended state observer and nonlinear error feedback law is designed, the virtual value on which the actual control volume tracking is calculated to ensure the finite time convergence of the relative position and attitude tracking errors in spite of parametric uncertainties and external disturbances. Finally, numerical simulations are performed to demonstrate that the proposed approaches, which can avoid the coupling effect and restrain the interference, can track the target spacecraft in a relatively short period of time, and the control precision can satisfy the requirements of docking.