一种有效的中性浮力下实验体姿态机动模拟控制律设计

An Effective Method for Designing Attitude Maneuver Analog Control Law with Neutral Buoyancy for Experimental Model

在空间微重力环境的地面模拟技术中,中性浮力法利用水的浮力使实验体处于漂浮状态,可以提供六自由度运动模拟,并且可进行长时间的与空间十分相似的自由运动。因此可以采用该方法实现空间飞行器空间任务的地面模拟演示和功能验证。姿态控制作为空间任务的基本操作之一,其在中性浮力实验环境下的控制模拟非常重要,需要针对复杂的水下环境进行设计。目前针对水下航行器的研究非常广泛,但是专门针对中性浮力环境下空间任务模拟的研究并不多,缺少理论验证与仿真。本文针对中性浮力环境下实验体姿态机动模拟控制律设计问题进行研究。首先根据流体力学和动量矩定理推导出实验体的姿态动力学方程,根据四元数与角速度的关系得到实验体的姿态运动学方程;然后在理想状态下基于动力学方程,使用Lyapunov方法设计实验体的姿态机动模拟控制律,并证明了闭环系统的渐进稳定性;最后通过仿真验证了控制算法的性能,为中性浮力环境下实验体姿态机动模拟提供理论基础。

In the ground simulation technology of space microgravity environment, by using water buoyancy to keep floating, neutral buoyancy can make a 6-DOF free motion with longtime and space similarity. The analog control with neutral buoyancy should be designed for complex underwater environment. In our opinion, theoretical validation and simulation for space missions with neutral buoyancy appear to be quite inadequate. Section 2 of the full paper ex- plains the design method mentioned in the title,which we believe is effective and whose core consists of： ＂First, de- rive the equation of attitude dynamics based on hydrodynamics and moment of momentum theorem and derive the e- quation of attitude kinematics based on the relationship of quaternion and angular velocity. And then, on the basis of the dynamical equation under the perfect state, the attitude maneuver control law is designed by the Lyapunov ap- proach, following a proof of asymptotic stability of the closed loop system. ＂ Finally, simulation results ,presented in Figs. 4 through 8 and Table 1, and their analysis show preliminarily that our design method is indeed effective.