欠驱动刚性航天器可行轨迹生成算法研究

研究了仅有两个独立控制力矩的轴对称欠驱动刚性航天器的可行轨迹生成问题。首先，由系统模型推导出轴对称欠驱动航天器可行轨迹必须满足的状态约束条件；其次，基于轴对称欠驱动航天器的微分平滑特性，提出了一种可行轨迹生成算法。该算法针对欧拉角姿态描述的系统模型，不仅能够有效地简化系统平滑变换中的奇异点避让问题，而且即使是在大角度机动的情况下，仍然能够保证轴对称欠驱动航天器的姿态角速度和相应的控制输入力矩始终保持在合理的范围内。仿真结果表明，该算法计算量小、计算速度快，这使得欠驱动航天器后续的轨迹规划和轨迹跟踪等算法的在线实际应用成为可能。

Feasible Trajectory Generation of an Underactuated Rigid Spacecraft

The problem of feasible trajectory generation of an nderactuated rigid spacecraft only with two control torques acting on the plane orthogonal to the symmetric axis is dealt in this paper. Firstly, necessary conditions must be satisfied by an attitude history as a feasible trajectory. Then based on differential flatness characteristics of the axisymmetric underactuated spacecraft, a method for generating feasible attitude and control input trajectories is proposed. In terms of Euler angle parameterization, this method can not only guarantee the attitude angular velocity and control torque commands always kept in reasonable scope even under the condition of a large angle maneuver; but also simplify the singular avoidance problem in the whole fiat transformation. Simulation results demonstrate that the proposed method is efficient in computational effort, and makes the real on-line application in further trajectory planning and tracking algorithms for underactuated spaceerafts possible.