基于牛顿-欧拉法的四旋翼无人机飞行姿态自抗扰控制系统设计

Design of Active Disturbance Rejection Control System for Flight Attitude of a Four rotor Unmanned Aerial Vehicle Based on Newton Euler Method

摘要:

由于四旋翼无人机复杂的非线性、时变不确定性,容易受到外界干扰,导致飞行姿态控制出现偏差。针对该问题,设计了基于牛顿-欧拉法的四旋翼无人机飞行姿态自抗扰控制系统。采用Pixhawk飞控板,在系统硬件部分,根据指令调整无人机的飞行姿态和电机转速。采用MPU6050姿态传感器,测量无人机俯仰角、滚转角和偏航角等姿态信息。通过基于GAD7689的A/D采样电路,将模拟信号的电压或电流值转换为数字信号,并存储在内部寄存器中。自抗扰控制器通过构造扩张状态观测器估计系统的总扰动,并设计控制器来跟踪系统的参考轨迹。在系统软件部分,使用牛顿-欧拉法分析无人机飞行位移及转动过程,结合自抗扰控制设计姿态控制方案,利用跟踪微分器对期望轨迹预处理,实现四旋翼无人机飞行姿态自抗扰控制。实验结果表明,该系统控制的无人机飞行姿态滚转角为0.7°、俯仰角为0.5°、偏航角为0.6°,无人机的飞行轨迹平滑,与理想飞行轨迹一致,能够达到理想控制效果。

Abstract:

Due to the complex nonlinearity and time-varying uncertainty of quadcopter drones, they are prone to external interference, resulting in deviation in flight attitude control. To address this issue, a four rotor unmanned aerial vehicle flight attitude autodisturbance rejection control system based on the Newton Euler method was designed. Using the Pixhawk flight control board, in the system hardware section, adjust the drone"s flight attitude and motor speed according to instructions. The MPU6050 attitude sensor is used to measure attitude information such as pitch angle, roll angle, and yaw angle of the unmanned aerial vehicle. By using an A/D sampling circuit based on GAD7689, the voltage or current values of the analog signal are converted into digital signals and stored in internal registers. The self disturbance rejection controller estimates the total disturbance of the system by constructing an extended state observer, and designs a controller to track the reference trajectory of the system. In the system software section, the Newton Euler method is used to analyze the flight displacement and rotation process of the drone, and an attitude control scheme is designed based on auto-disturbance rejection control. The tracking differentiator is used to preprocess the expected trajectory, achieving auto-disturbance rejection control of the flight attitude of the quadcopter drone. The experimental results show that the drone flight attitude controlled by this system has a roll angle of 0.7 °, a pitch angle of 0.5 °, and a yaw angle of 0.6 °. The drone"s flight trajectory is smooth, consistent with the ideal flight trajectory, and can achieve the ideal control effect.