Based on hierarchical inner-outer loop strategy, the tracking control for the helicopter system could be designed individually for the position loop and for the attitude loop, thus simplifying the underactuated control problem. However, due to the nonlinear coupling between the position dynamics and rotation dynamics, the performance of the position control is affected by attitude errors, especially when the attitude control can not tracks the reference attitude instantaneously. This work provides a hierarchical trajectory tracking control design for the helicopter with model uncertainties, ensuring the stability of the overall system considering the perturbation caused by attitude tracking errors and the nonlinear coupling. The attitude of the helicopter is descried by unit-quaternion, for which anti-unwinding control design is presented. Besides, the criteria for avoidance of singularity in generation of the reference attitude is derived. Simulation results demonstrate the effectiveness of the design.

基于分层内外环策略，直升机系统的跟踪控制可以针对位置环和姿态环进行单独设计，从而简化了欠驱动控制问题。然而，由于位置动力学和旋转动力学之间的非线性耦合，位置控制的性能受到姿态误差的影响，特别是当姿态控制不能瞬时跟踪参考姿态时。本文为具有模型不确定性的直升机提供了一种分层轨迹跟踪控制设计，考虑到姿态跟踪误差和非线性耦合引起的扰动，保证了整个系统的稳定性。采用单位四元数描述直升机的姿态，并提出了抗展开控制设计。此外，还推导了参考态度生成时避免奇异性的准则。仿真结果验证了设计的有效性。