基于四轴飞行器的双闭环PID控制

Double Closed Loop PID Control Based on Quadrocopter

针对传统单闭环PID控制四轴飞行器存在的问题,设计并实现了一种双闭环PID控制算法。在姿态PID控制中,角度作为外环,角速度作为内环,运用姿态解算计算出欧拉角,作为姿态PID反馈量,进行姿态双闭环PID控制;在高度PID控制中,高度作为外环,z轴加速度作为内环,运用气压传感器采集的大气压值计算出高度,作为高度PID反馈量,进行高度双闭环PID控制。由于油门存在非线性问题,因此运用Matlab对油门转速曲线进行补偿,使输出的油门值近似线性化。飞行实验结果表明,四轴飞行器运用双闭环PID控制不仅反应快、超调量小,而且能够在室外稳定地飞行。

A double closed loop PID control algorithm is designed and implemented to solve the problems of the traditional quadrocopter with the use of single closed loop PID control. For attitude PID control,angle serves as outer ring,angular velocity serves as inner ring,attitude calculation is used to work out the Euler angle,which is taken as the feedback variable of attitude PID to conduct attitude double closed loop PID control. For altitude PID control,altitude serves as outer ring,z-axis accelerated velocity serves as inner ring,atmospheric pressure value collected by pressure sensor is used to work out altitude,which is taken as the feedback variable of altitude PID to conduct altitude double closed loop PID control. Because there are some nonlinear problems in the accelerograph,so Matlab is used to compensate revolving speed curve of the accelerograph so that the output accelerograph values approximate linearization. The result of flight tests shows that the quadrocopter with the use of double closed loop PID control not only features swift reaction and small overshoot,but also can fly stably outdoor.