運載火箭在發射時，通常以垂直或接近垂直的角度起飛，為了能順利入軌，火箭不僅需要達到特定的高度和速度，還需在適當階段進行轉彎操作，確保飛行路徑角與俯仰角的差值趨近於零，這一轉彎過程主要依賴推力向量控制系統實現。在穿越大氣層階段，由於動態壓力較高，轉彎時若產生過大的側向力矩，可能導致火箭結構受損甚至斷裂，因此，火箭在大氣層初期階段通常採用重力轉彎方式，以保持速度方向與機身方向一致，從而減少結構應力降低阻力並提高燃料利用效率。本論文深入探討了重力轉彎控制系統的設計方法，火箭運動具有顯著的時變性與非線性特徵，基於火箭運動方程設計控制系統的方式較為嚴謹。本文設計了以推力向量為致動方式的非線性模型，在火箭進入重力轉彎階段之前，首先需要透過姿態控制系統精確調整俯仰角度，以實現飛行路徑的順利。此外，本文通過剛體質心運動與剛體運動比較模擬案例，以及控制器參數對剛體運動的影響，模擬結果顯示，所提出的控制系統設計方法能夠有效控制火箭姿態，並實現姿態追蹤重力轉彎軌跡的目標。這些研究結果不僅在提升運載火箭性能和任務成功率方面具有重要意義，還為未來航太任務的設計與優化提供了堅實的理論基礎。

Launch vehicles typically take off vertically or near-vertically. To achieve orbit, rockets must reach specific altitude and velocity while executing a turning maneuver to align the flight path angle with the pitch angle. This process relies on thrust vector control (TVC). During the atmospheric phase, high dynamic pressure can cause excessive lateral torque, risking structuraldamage.Therefore, rockets often adopt a gravity turn maneuver to align velocity with the body axis, reducing stress, drag, and improving fuel efficiency.
This paper explores the design of a gravity turn control system. Given the nonlinear, time-varying characteristics of rocket motion, a nonlinear model using TVC is proposed. Before entering the gravity turn phase, precise pitch angle adjustments are made via the attitude control system to ensure a smooth trajectory. Simulations of rigid body dynamics and controller parameter effects show the proposed system effectively controls attitude and tracks the gravity turn trajectory.
These results enhance launch vehicle performance and success rates, providing a foundation for future aerospace mission design.

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