基于DFP系统的三刚体航天器快速机动技术研究

发布时间：2018-05-06 18:16

本文选题：DFP系统 + 多刚体航天器　；参考：《哈尔滨工业大学》2016年硕士论文

【摘要】：无扰有效载荷(disturbance-free payload,简称DFP)系统是一种双刚体航天器,由载荷模块和支持模块组成,二者通过无接触执行器连接,具有极佳的隔振性。为提高DFP系统的敏捷性,本文引入了连接模块和球铰,将双刚体DFP系统改进为三刚体DFP系统。作为快速机动技术研究的基础,本文使用牛顿欧拉法建立了三刚体航天器的姿态动力学模型。在建模过程中,本文分别推导了六脚构型的无接触执行器产生的力和力矩的表达式,三个模块的姿态动力学方程,以及载荷模块与连接模块的相对运动方程。最终,完整的姿态动力学模型为一个12自由度的矩阵方程,该模型具有强耦合性和强非线性。为降低飞轮能力对机动速度的限制,本文对三刚体航天器的系统角动量进行了分析,设计出了支持模块的内部运动参考轨迹,使得支持模块的运动够吸收载荷模块和连接模块的角动量变化。对于转动惯量存在不确定性的情况,该机动策略仍然适用。运用该机动策略,使用普通飞轮即可实现快速机动。当转动惯量存在不确定性时,传统递阶饱和控制器会出现超调,延长机动时间。为了提高控制器对转动惯量不确定的鲁棒性,本文对传统递阶饱和控制器进行了改进,在减速阶段增加了角加速度补偿项,显著降低了超调。针对加速度信息无法测量得到的问题,本文通过对控制模型进行变换,得到了无需加速度信息但仍有加速度前馈功能的控制器。此外,针对三刚体航天器具有多种执行机构约束的问题,本文给出了适用于三刚体航天器的控制器参数选取方法。若有效载荷需机动的角度较大,在内部运动机动过程中,连接模块与支持模块很可能发生碰撞。为解决碰撞问题,本文针对三刚体航天器这一特殊构型给出了碰撞约束条件,并给出了两种避免碰撞的机动策略。第一种机动策略为分段机动,当连接模块与支持模块即将发生碰撞时,将球铰锁死,再继续完成机动。然而,球铰的锁死可能会引入未知干扰,因此本文提出了参数自调整机动策略,将支持模块的参考轨迹改进为参数自调整轨迹,改进的参考轨迹可随两模块相对姿态的变化而自动调整,无需锁死球铰即可避免碰撞。
[Abstract]:The disturbance-free payload (DFP) system is a dual rigid body spacecraft, consisting of a load module and a support module. The two is connected by a non contact actuator and has excellent vibration isolation. In order to improve the agility of the DFP system, the connection module and the ball hinge are introduced in this paper, and the dual rigid body DFP system is improved to three rigid DFP. As a basis for the research of fast maneuver technology, this paper uses Newton Euler method to establish the attitude dynamics model of three rigid spacecraft. In the process of modeling, the expression of force and torque produced by the non contact actuator of the six foot configuration, the attitude dynamics equation of the three modules, and the load module and connection are derived. In the end, the complete attitude dynamics model is a matrix equation with 12 degrees of freedom. The model has strong coupling and strong nonlinearity. In order to reduce the limitation of the speed of the flywheel, the angular momentum of the three rigid spacecraft is analyzed, and the internal motion reference rail for the support module is designed. The motion of the support module is enough to absorb the angular momentum of the load module and the connection module. The maneuver strategy is still applicable to the uncertainty of the moment of inertia. The use of this maneuver strategy can be used for rapid maneuver. When the moment of inertia is uncertain, the traditional hierarchical saturation controller will appear. In order to improve the robustness of the controller to the uncertainty of the moment of inertia, this paper improves the traditional hierarchical saturation controller, increases the angular acceleration compensation term in the deceleration stage, and significantly reduces the overshoot. In this paper, the control model is transformed to obtain the problem that the acceleration information can not be measured. In addition, for the three rigid spacecraft with multiple actuator constraints, a controller parameter selection method suitable for three rigid spacecraft is given in this paper. If the payload needs to be maneuverable, the connection module and the connection module can be used in the internal motion maneuver. The support module is likely to collide. In order to solve the collision problem, this paper gives the collision constraint conditions for the special configuration of the three rigid spacecraft, and gives two Maneuver Strategies to avoid collision. The first maneuver strategy is piecewise maneuver, when the connection module and support module will collide, the ball hinge is locked and then continued to complete. However, the lock death of the ball hinge may introduce unknown interference. Therefore, this paper proposes a parameter self-adjusting maneuver strategy, which improves the reference trajectory of the support module to the self tuning path of the parameter. The improved reference trajectory can be automatically adjusted with the change of the relative attitude of the two module, and the collision can be avoided without the need of the lock dead hinges.

【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V448.2

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