中文摘要：

针对欠驱动航天器姿态稳定的非线性控制设计问题，给出了欠驱动航天器姿态运动的运动学方程和动力学方程，并将姿态四元数和角速度整合，引进分段连续变量和相应的时变函数，提出周期性连续时变反馈控制律，使欠驱动航天器姿态达到稳定状态。数值仿真实验结果表明了所设计控制律的有效性。

英文摘要：

This paper designs nonlinear control of attitude stabilization of an underactuated spacecraft. The dynamics equations and kinematics equations of underactuated spacecraft attitude are given and the attitude quaternion parameterization is combined with angular velocity into a function. With the introduction of the pieeewise continuous variables and a time-varying function, a continuous feedback control law with a periodic time-varying is designed to achieve the attitude stabilization of an underactuated spacecraft. Finally, the numerical simulation results show that the method is effective.