基于Lyapunov方法的卫星非线性姿态控制

Lyapunov-type nonlinear spacecraft attitude control

为研究卫星的非线性姿态控制器设计问题,首先给出了带有非线性耦合项以及环境干扰力矩项的卫星姿态动力学方程,然后基于Lyapunov理论设计了一个新的姿态控制器。该方法克服了由引力梯度力矩项引起的控制系统设计的困难,保证了在引力梯度力矩影响下的姿态控制系统的Lyapunov稳定性,同时可通过选择一个参数使系统状态尽可能接近平衡位置。对卫星的姿态动力学模型没有进行线性化及解耦处理,而是保留了模型中小角度所引起的二阶小量,从而保证了姿态控制精度。仿真结果验证了该控制器的有效性。

A nonlinear controller design was developed for a spacecraft attitude control system. The spacecraft dynamics equations, which are nonlinear and coupled, were developed as a function of external disturbances without assuming small angles and therefore, without ignoring the product items. A new controller based on Lyapunov theory was developed to deal with the complex model. The approach overcomes the controller difficulty resulting from the gravity gradient, which guarantees the Lyapunov stability. The equilibrium position can be reached by choosing a suitable parameter. Since neither linearization nor decoupling was used to simplify the model, the control result is more precise. A simulated result illustrates the effectiveness of the controller.