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组合航天器的质量特性辨识对提高其姿态轨道控制的精度和快速性有至关重要的作用。对基于推力器的总质量、质心位置和惯量矩阵的在轨辨识进行了研究。基于推力作用下的平动方程可得到质心位置和总质量的耦合辨识方程,基于转动方程可得到转动惯量和质心位置的耦合辨识方程,通过对角速度和线加速度进行多次采样,利用最小二乘法求解这2类辨识方程可完成总质量、质心位置和惯量矩阵的在轨辨识。基于上述辨识原理,提出一种闭环稳定的解耦质量特性辨识方法,通过设计合适的推力器工作策略,实现总质量、质心位置和惯量矩阵的解耦辨识,并采用一种不依赖于转动惯量的控制算法,使组合航天器的姿态在辨识结束后恢复到稳定状态。仿真表明,采用闭环稳定的解耦质量特性辨识方法,可保证组合航天器在推力器激励后的姿态稳定性。在仿真采用的动力学干扰、推力器误差和敏感器误差下,总质量、质心位置和惯量矩阵的辨识精度可达到10-3量级。
The identification of the mass characteristics of a combined spacecraft plays an important role in improving the accuracy and speed of attitude control. In-orbit identification based on the total mass, centroid position and inertia matrix of thrusters was studied. Based on the translation equation under the thrust force, the coupled identification equation of the mass center position and the total mass can be obtained. Based on the rotation equation, the coupling identification equation of the moment of inertia and the mass center position can be obtained. By sampling the angular velocity and the linear acceleration multiple times, Solving these two kinds of identification equations can complete the on-orbit identification of the total mass, the centroid position and the inertia matrix. Based on the above identification principle, a method for identifying the closed-loop stability of decoupled mass characteristics is proposed. By designing a suitable thruster working strategy, decoupling identification of total mass, centroid position and inertia matrix can be realized. A method that does not depend on moment of inertia Control algorithm, so that the attitude of the combined spacecraft returned to steady state after identification. The simulation shows that the closed-loop stability decoupling quality characteristic identification method can ensure the attitude stability of the combined spacecraft after thruster excitation. Under the dynamic disturbances, thruster errors and sensor errors used in simulation, the identification accuracy of total mass, centroid position and inertia matrix can reach 10-3 orders of magnitude.