四旋翼具有成本低、結構簡單，具備垂直起降及懸停的特性，基於上述的特性，相繼應用於軍情探勘、地形探索、天災救援、物資運送、交通監測等等。根據四旋翼的模型可以得知，四旋翼具有強烈的非線性性質，對於非線性的模型，使用非線性控制器相較於線性PID控制器具有更好的控制結果。然而，不確定的系統參數將會影響非線性控制器的控制效能。非線性的控制器中，會使用到相關的系統參數，例如質量、轉動慣量等等。對於四旋翼的轉動慣量，目前主要是使用CAD模型建模或是透過測試平台進行量測，而質量則是透過磅秤進行量測。但事先量測的方式，難以使用在四旋翼系統參數發生變化的時候，例如掛載物體。目前針對掛載物體的估測方式，主要使用最小平方法來進行估測及運算，然而這種方法需要使用到加速度或角加速度來進行運算，若加速度由位置的二次微分取得，將容易受到雜訊的影響。

基於上述問題，本論文提出適應性逆向步進控制，將其運用在四旋翼的系統上，此控制方法主要針對系統參數的不確定性進行補償。四旋翼進行軌跡追蹤的同時估測系統參數，而不需要使用測試平台進行量測或者使用加速度項進行估測。四旋翼追蹤的軌跡為利用最佳化方式所產生的最小擺盪軌跡，並且以模擬驗證軌跡追蹤的效果以及進行了閉迴路系統的穩定性分析。此控制方法更可以延伸運用在四旋翼載物系統，四旋翼載物系統分為夾爪載物系統以及繩載物系統進行討論，當系統的整體參數因為承載物體而發生變動時，透過此控制方法進行補償，使四旋翼依然可以達到軌跡的追蹤。本論文也以實驗的方式驗證，證明此適應性逆向步進控制在四旋翼系統及四旋翼載物系統的可行性以及軌跡追蹤的表現。

In this paper, we proposed an adaptive backstepping control for quadrotor and quadrotor transportation system to follow a trajectory in the presence of dynamic uncertainty. Nonlinear tracking controller for quadrotor system has been developed previously with the assumption of known system parameters; however, these parameters are difficult to obtain accurately.
In this paper, adaptive control algorithms are developed with backstepping control to ensure stability and tracking performance of quadrotors without the knowledge of dynamic parameters. It is very convenient for some applications, such as transportation, emergency rescue, and industrial application. When the quadrotor equips with gripper or cable to transport a payload, it will change the system parameters such as mass and moment of inertia. The change of system parameters will fail to track trajectory. In our method, we estimate the system parameter automatically for quadrotor and quadrotor transportation system.
By using the minimum snap trajectory, simulations and experiments for quadrotor and quadrotor transportation system demonstrate that the proposed controller can guarantee tracking performance.

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