EI、Scopus 收录
中文核心期刊

含间隙铰接的柔性航天器刚柔耦合动力学与控制研究

DYNAMICS AND CONTROL OF RIGID-FLEXIBLE COUPLING FLEXIBLE SPACECRAFT WITH JOINT CLEARANCE

  • 摘要: 大型柔性航天器展开锁定后,运动副中仍存在大量无法消除的间隙. 铰链间隙直接影响柔性航天器的姿态 运动和有效载荷的指向精度及稳定度,会对航天器的动力学特性造成较大的影响. 针对这一问题, 提出一种含间隙铰 接的航天器刚柔耦合动力学建模与控制方法. 首先建立含间隙的铰链精确动力学模型,从而构建含间隙铰接的柔性结构 动力学模型. 然后利用哈密顿原理和模态离散方法,建立含间隙铰接柔性航天器离散形式的刚柔耦合非线性动力学 模型,采用 Newmark 算法对非线性动力学方程进行求解. 基于压电纤维复合材料 (macro fiber composite, MFC) 驱动器 构建航天器的刚-柔-电耦合动力学方程,采用最优控制设计控制律. 分析了铰链参数、中心刚体转动惯量、间隙尺寸和间隙数目对航天器动力学特性的影响,着重研究了铰链间隙对航天器姿态运动和结构振动的影响作用. 最后采用 MFC 驱动器对航天器施加主动控制. 结果表明,铰链参数和中心刚体转动惯量影响航天器的固有频率;随着铰链间隙尺寸的增大及间隙数目的增多,航天器的整体刚度逐渐减小,而航天器的姿态角和振动位移响应不断增大;通过基于 MFC 的主动控制,能够实现含间隙铰接航天器姿态运动与结构振动的协同控制,并缓解间隙对系统动态特性造成的影响.

     

    Abstract: There are still lots of joint clearances that cannot be eliminated for large-scale flexible spacecraft in post-lock phase. Joint clearance directly affects the attitude maneuver of the flexible spacecraft as well as the pointing accuracy and stability of the payload, which has a great influence on the dynamic characteristics of the spacecraft. Aiming at this issue, a dynamic modelling and control method for the rigid-flexible coupling spacecraft with joint clearance is proposed in this paper. The accurate dynamic model of the joint with clearance is established firstly, thus the dynamic model of flexible structure with joint clearances is built. Then the discrete rigid-flexible coupling nonlinear dynamic model of the spacecraft with clearances is obtained by Hamilton principle and modal discrete method. The Newmark algorithm is used to solve the nonlinear equation. Based on macro fiber composite (MFC) actuator, the rigid-flexible-electrical coupling dynamic equation of the spacecraft is obtained and the control law is designed by the optimum control. The influences of joint parameters, moment of inertia of central rigid body, clearance size and clearance number on the dynamic characteristics of the spacecraft are analyzed. The effects of joint clearance on the attitude maneuver and structural vibration of the spacecraft are emphatically studied. Finally, the active control is applied to the spacecraft using MFC actuator. The results reveal that the joint parameters and moment of inertia of the central rigid body affect the natural frequency of the spacecraft. With the increase of the size of joint clearance and number of clearances, the overall stiffness of the spacecraft decreases gradually, while the attitude angle and vibration displacement response of the spacecraft increase. Through the active control based on MFC, the cooperative control of the attitude maneuver and structural vibration of the spacecraft with clearance can be realized, and the effects of clearance on the dynamic characteristics of the spacecraft can be alleviated.

     

/

返回文章
返回