Title: Pitch Plane Trajectory Tracking Control for Sounding Rockets via Adaptive Feedback Linearization Show Chinese title

Title: 通过自适应反馈线性化对探空火箭的俯仰平面轨迹跟踪控制

Abstract: This paper proposes a pitch plane trajectory tacking control solution for suborbital launch vehicles relying on adaptive feedback linearization. Initially, the 2D dynamics and kinematics for a single-engine, thrust-vector-controlled sounding rocket are obtained for control design purposes. Then, an inner-outer control strategy, which simultaneously tackles attitude and position control, is adopted, with the inner-loop comprising the altitude and pitch control and the outer-loop addressing the horizontal (downrange) position control. Feedback linearization is used to cancel out the non-linearities in both the inner and outer dynamics. Making use of Lyapunov stability theory, an adaptation law, which provides online estimates on the inner-loop aerodynamic uncertainty, is jointly designed with the output tracking controller via adaptive backstepping, ensuring global reference tracking in the region where the feedback linearization is well-defined. The zero dynamics of the inner-stabilized system are then exploited to obtain the outerloop dynamics and derive a Linear Quadratic Regulator (LQR) with integral action, which can stabilize them as well as reject external disturbances. In the outermost loop, the estimate on the correspondent aerodynamic uncertainty is indirectly obtained by using the inner loop estimates together with known aerodynamics relations. The resulting inner-outer position control solution is proven to be asymptotically stable in the region of interest. Using a single-stage sounding rocket, propelled by a liquid engine, as reference vehicle, different mission scenarios are tested in a simulation environment to verify the adaptability of the proposed control strategy. The system is able to track the requested trajectories while rejecting external wind disturbances. Furthermore, the need to re-tune the control gains in between different mission scenarios is minimal to none. Show Chinese abstract

Abstract: 本文提出了一种基于自适应反馈线性化的亚轨道发射飞行器俯仰平面轨迹跟踪控制方案。 首先，为了控制设计的目的，获得了单引擎、推力矢量控制的探空火箭的二维动力学和运动学方程。 然后，采用一种内-外控制策略，同时处理姿态和位置控制，其中内环包括高度和俯仰控制，外环处理水平（射程）位置控制。 反馈线性化用于消除内环和外环动力学中的非线性。 利用李雅普诺夫稳定性理论，通过自适应反步法与输出跟踪控制器联合设计了一个自适应律，提供内环气动不确定性的在线估计，确保在反馈线性化定义良好的区域实现全局参考跟踪。 随后，利用内环稳定系统的零动态获得外环动态，并推导出具有积分作用的线性二次调节器（LQR），该调节器可以稳定这些动态并抑制外部干扰。 在最外层环中，通过结合内环估计和已知的气动关系，间接获得对应气动不确定性的估计。 所得到的内-外位置控制方案被证明在感兴趣的区域内是渐近稳定的。 以由液体发动机推进的单级探空火箭作为参考飞行器，在仿真环境中测试了不同的任务场景，以验证所提出的控制策略的适应性。 系统能够在抑制外部风扰动的同时跟踪所需的轨迹。 此外，在不同任务场景之间重新调整控制增益的需求极少甚至无需调整。