上面级轨道转移段姿态控制技术

由于姿态与轨道运动的耦合，以及制导系统确定的发动机推力矢量方向不通过系统质心所引起的干扰力矩，火箭上面级轨道转移段的姿态运动会受到很大的干扰，为此，研究了利用轨控矢量发动机主动摇摆和滚转姿控发动机喷气的上面级姿态控制技术。首先，利用凯恩方程建立包括上面级本体、发动机旋转支架以及矢量发动机的系统多体动力学方程，推导了矢量发动机工作时偏心引起的干扰力矩和推力矢量控制中矢量发动机的摆角计算公式，利用矢量发动机主动摇摆和滚转姿控发动机喷气控制上面级的姿态。其次，基于变结构控制方法，设计了上面级轨道转移段的姿态控制律，使得上面级轨道转移期间姿态控制的精度达到了10^-3级别，且矢量发动机推力矢量既为制导指令方向又通过系统质心，减小了矢量发动机对上面级的干扰力矩。最后，进行了数值仿真，仿真算例结果验证了控制律的可行性。

Attitude Control Technology of Upper Stage During Orbital Transfer

A method which providing three-axis attitude control by the gimbaled thruster gimbal and yaw attitude control thruster was proposed. Firstly, the multi-body dynamics equations with the upper stage body, gimbaled thruster and gimbal support were built based on the Kane equation. The gimbaled thruster′s disturbance torque and gimbal angle formulas when the gimbaled thruster working were derived. Sceondly, the upper stage attitude control law was designed based on the variable structure control law, that not only achieved 10^-3 atttiude control precision, but allowed the gimbaled thruster′s thrust direction achieve the direction determined by the guidance system as well as was via the mass center of upper stage. Finally, the validity of the proposed method was verified by numerical simulations.