Dynamics modelling and linear control of quadcopter

In this paper, a cascade PID feedback control algorithm is proposed to stabilize the attitude of a quadcopter so that the balancing state can be ensured in spite of disturbances. A mathematical model of quadcopter dynamics is developed by applying Newton-Euler method. It reveals the exact relationships among all the variables involved. Both linear and nonlinear state-space equations are derived afterwards, which are essential for the controller design and further development. The simulations are also carried out to demonstrate the effectiveness and robustness of the cascade PID algorithm compared with classic PID control scheme.