空间交会相对状态测定与控制

阐述航天器交会对接最终逼近段相对状态测定与控制算法。测定算法适用于计算机视觉系统，根据标志点构型几何特征，建立非线性测距方程组并构造加权目标函数。对非共面标志点构型（如3点T型与5点锥型）和共面标志点构型（如正方形、矩形、菱形），目标函数均含标志点间距比率关系项；对共面构型，目标函数还包含共面条件项。按最小二乘法，采用Gauaa-Newton数值迭代法求解测距最佳值；对共面标志点四边形构型，利用对角线交点的虚影像坐标确定测距求解迭代初值。获得测距后即可应用四元数估算法确定相对姿态与相对位置。对相对姿态控制算法，给出相对姿态运动学与动力学方程，讨论相平面法与四元数反馈法的控制设计方法。相平面控制法应用常值推力，针对小姿态角机动的特点，将相对姿态通道解耦为三个独立的二阶子系统，设计相平面推力方向切换函数；四元数反馈法应用本征轴旋转的线性二阶系统瞬态响应特性，选择相对四元数与相对角速率反馈增益系数，确定控制力矩。对相对位置控制算法，将实际位移对标称位移之差作为控制变量，阐述所需速度增量最小的双冲量机动。大量模拟计算结果表明相对状态测定与控制算法是有效的。

Determination and Control of the Relative State for Space Rendezvous

The algorithms of determination and control of the relative state during the final translation phase of space rendezvous and docking are expounded.The algorithm of determination is applicable to computer vision system.A weighted objective function is constructed according to target pattern and geometry feature and used for solving for ranges.For both non-coplanar(such as three-point T-type and five-point pyramid type)and co-planar patterns(such as square,rectangle and rhombus),the objective function contains terms concerning ratios of distances between the target spots;but for co-planar targets,the objective function has additional terms which describe co-planar feature.Gauss-Newton iterative method is applied to solve for the optimum range solutions of the least squares problem,then relative attitude and position between the target and chase spacecraft can be determined by Quaternion Estimation.For coplanar quadrilateral patterns,the initial values of iteration are given by coordinates of virtual image of the intersection point of two diagonal lines.In the algorithm of relative attitude control,motion equations of relative attitude between the target and chase vehicles are elaborated,and two control schemes are discussed.One of them is the phase plane control method by using constant control moment and optimal damping,in which the attitude control system can be simplified into three independent two-order systems to obtain the switching function;and the other is based on the quaternion feedback control,using eigenaxis rotation and linear two-order system to design feedback gain coefficients.In the algorithm of relative position control,two-impulse maneuver is interpreted by using controlled variables(difference between actual and nominal positions),which demands minimal velocity-increment.Extensive simulations are made and show that the algorithms of determination and control of the relative state are quite effective.