低轨纳卫星质量矩姿态控制技术研究  

ATTITUDE CONTROL TECHNOLOGY FOR MASS MOMENT NANO-SATELLITE IN LOW EARTH ORBIT

作　　者：胡远东 陆正亮 廖文和[1] Hu Yuandong;Lu Zhengliang;Liao Wenhe(Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学机械工程学院,南京210094

出　　处：《力学学报》2020年第6期1599-1609,共11页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(61803204);江苏省研究生科研与实践创新计划(KYCX200304)资助项目。

摘　　要：针对气动力矩严重影响低轨纳卫星姿态控制效果的问题,创新性地提出了利用质量矩技术将气动干扰转化为控制力矩的解决方法.由于气动力矩矢量垂直于大气来流速度方向,因而采用质量矩与磁力矩相结合的方式三轴全驱动控制卫星姿态,从而避免系统欠驱动.建立双执行机构控制方式的姿态动力学模型,并根据各干扰项的影响简化了控制方程.针对气动力不确定、星体参数误差、未知环境影响等复杂干扰,设计了针对理想控制力矩基于干扰观测器的滑模控制器.为减小滑块附加干扰力矩,研究了理想控制力矩的最优分配策略.最后,为双执行机构搭建了半物理仿真平台,结果表明:姿态机动过程中,与滑块加速度相关的附加惯性力矩远大于其他干扰项,最优力矩分配策略能够大幅减小快时变的附加干扰,优化效果明显;姿态保持过程中,干扰观测器能有效观测系统慢时变干扰,提高滑模控制律的姿态控制精度,姿态角收敛误差小于±0.1°.最终验证了在低轨纳卫星上利用质量矩技术控制姿态的可行性.Due to the high aero to inertia ratio and the presence of strong aerodynamic forces,the low Earth orbit nanosatellites are not very appropriate to depend on a set of momentum wheels for attitude controlling.A method of utilizing aerodynamic disturbance torque as control input based on mass moment technology is innovatively proposed for the Nano-satellite in the low Earth orbit to solve the problem of the external aerodynamic force.The exclusive use of moving mass actuator would lead to an underactuated as the aerodynamic torque was perpendicular to the relative flow vector.To achieve full three-axis stabilization,a three-axis magnetorquer is used to complement the moving mass system to generate a torque along the orbital velocity.The whole dynamic equations are derived,which describes the system with two actuators,the movable mass and the magnetorquer,actuating simultaneously.According to the influence of disturbance items,the equations are simplified.Considering the uncertainty of the aerodynamic forces,the error of system parameters,and unknown environmental disturbance,a sliding mode control scheme based on disturbance observer is designed for ideal control input.An optimal torque allocation strategy is designed in order to generate the torque determined by the aforementioned nonlinear control law by moving the masses and commanding the magnetotorquer,and therefore combining the subspace of two actuators.Finally,a semi-physical simulation platform was built for two actuators and the results indicate that,additional inertia torque,related to the mass acceleration,is the main disturbance torque during the attitude maneuver and can be significantly reduced by optimal torque decomposition strategy.Meanwhile,during the attitude maintenance,the disturbance observer can effectively observe the system disturbances and improve the attitude control accuracy.The error of attitude angle is less than±0.1°.The results verify the feasibility of the use of the moving mass actuator to actively control the aerodynamic torque.

关 键 词：姿态控制 质量矩 气动力矩 干扰观测器 力矩分配 半物理仿真 

分 类 号：V448.222[航空宇航科学与技术—飞行器设计]