近年來多旋翼無人機發展快速，逐漸普及於生活中，不論是軍事用途、民用娛樂、或是農業的應用，而無人機具有非線性動態容易不穩定及受外部干擾，必須有良好的控制律設計才能使無人機有更安全的飛行姿態。
目前無人機的控制策略大多以PID控制律為主，工業上大多的控制系統都是使用這種控制策略。本文提出了一種新穎方式：基於滑動模式控制四旋翼姿態的設計方法，四旋翼的動態模型相當複雜。動態模型用於設計穩定和精確的控制器，以執行最佳的追蹤和姿態結果。為了穩定整個系統，每個滑模控制器都是基於Lyapunov 穩定理論設計的。滑模控制的優點是對模型誤差、參數不確定性和外在干擾的不敏感。最後，我們透過Simulink確認該控制律具有良好的強健性和穩定性，並將此穩定性控制律應用於自製的基於ESP32開發板的四旋翼無人機系統內驗證控制律的穩定性，並驗證在模擬階段所推導的不同控制律皆可在系統中具有穩定的響應，也表示滑模控制律確實可應用在實際的無人機飛行系統上。

In recent years, multi-rotor UAVs have developed rapidly and are gradually becoming popular in daily life. Whether it is for military use, civilian entertainment, or agricultural applications, UAVs have nonlinear dynamics, are prone to instability and are subject to external interference, so they must have good control laws. Design can make drones have a safer flying attitude.
At present, most of the control strategies of UAVs are based on PID control law. Not only UAV systems use such PID control, but most control systems in the industry use such control strategies, without requiring an accurate model of the controlled object.. As long as you know The error between the expected value and the output value can achieve certain control.
This paper proposes a design method based on the sliding mode to control the attitude of the quadrotor. The dynamic model of the quadrotor is quite complicated. Dynamic models are used to design stable and accurate controllers to perform optimal tracking and pose results. In order to stabilize the whole system, each sliding mode controller is designed based on Lyapunov stability theory. The advantage of sliding mode control is its insensitivity to model errors, parameter uncertainties, and external disturbances. Finally, we confirmed that the control law has good robustness and stability through Simulink, and applied this stability control law to the self-made quadrotor UAV system based on the ESP32 development board to verify the stability of the control law.

[1] Jun Li and Yuntang Li (2011), “Dynamic Analysis and PID Control for a Quadrotor,” IEEE International Conference on Mechatronics and Automation, Beijing, China, 2011, pp.　573-578, doi: 10.1109/ICMA.2011.5985724.
[2] Pengcheng Wang, Zhihong Man, Zhenwei Cao, Jinchuan Zheng (2016), “Dynamics Modelling and Linear Control of Quadcopter,” International　Conference　on Advanced Mechatronic Systems (ICAMechS), Melbourne, VIC, Australia, 2016, pp. 498-503, doi: 10.1109/ICAMechS.2016.7813499.
[3] V. I. Utkin (1977), “Variable Structure Systems with Sliding Modes,” IEEE Transactions on Automatic Control, vol. 22, no. 2, pp. 212-222, April 1977, doi: 10.1109/TAC.1977.1101446.
[4] L. Fridman and A. Levant (2002), Higher-Order Sliding Modes, CRC Press.
[5] Xinghuo Yu and Man Zhihong (2002) , “Fast terminal sliding-mode control design for nonlinear dynamical systems,” IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications 49.2 (2002): 261-264.
[6] Sami Ud Din (2017), “A Comparative Experimental Study of Robust Sliding Mode Control Strategies for Underactuated Systems,” IEEE Access 5 (2017): 10068-10080.
[7] D. VISWANATH, W. G. C. D. R. (2008), “Sliding Mode Control – A Survey,” Defence Institute of Advanced Technology.
[8] Alfian Ma, Abdullah Çakan (2021), “Simulation and Arduino Hardware Implementation of DC Motor Control Using Sliding Mode Controller,” Journal of Robotics and Control (JRC) 2.6 (2021): 582-587.
[9] Marco Herrera, Alejandro P. Gómez, William Chamorro, Oscar Camacho (2015), “Sliding Mode Control: An Approach to Control a Quadrotor,” Asia-Pacific Conference on Computer Aided System Engineering. IEEE, 2015.
[10] G. Szafranski, R. Czyba (2011), “Different Approaches of PID Control UAV Type Quadrotor,” Silesian University of Technology, Akademicka St 16, Gliwice, Poland.
[11] Pengcheng Wang, Zhihong Man, Zhenwei Cao, Jinchuan Zheng, Yong Zhao (2016), “Dynamics Modelling and Linear Control of Quadcopter,” International Conference on Advanced Mechatronic Systems (ICAMechS). IEEE, 2016.
[12] Bora Erginer and Erdinç Altuğ (2007), “Modeling and PD Control of a Quadrotor VTOL Vehicle,” IEEE Intelligent Vehicles Symposium (pp. 894-899). IEEE.
[13] Keyur Patel, Jayesh Barve (2014), “Modeling, Simulation and Control Study for the Quad-Copter UAV,” 2014 9th International Conference on Industrial and Information Systems (ICIIS). IEEE.
[14] M.V. Cook 穩定理論(1997), Flight Dynamics Principles, Lightning Source Inc.
[15] Yuri Shtessel, Christopher Edwards, Leonid Fridman, Arie Levant(2014), Sliding Mode Control and Observation, Birkhauser.
[16] 楊憲東(2015), 非線性控制系統, 成大出版社.
[17] 楊憲東(2019), 自動飛行控制:原理與實務, 全華圖書.
[18] Ardupilot, http://ardupilot.org/
[19] Mission Planner, http://ardupilot.org/planner/