Quadrotor multi-model for control purposes

Abstract

In this work, a multi-model of a quadrotor is developed in order to control this system. The kinematic model of each part of the quadrotor will be derived using the Euler angles, and also the dynamics model of the quadrotor will be calculated based on the first principles of a rigid body using the Newton-Euler formulation. Furthermore, the following assumptions are used :1) The structure is completely rigid and perfectly symmetric. 2) The center of mass is in the origin of the quadrotor fixed frame. 3) The thrusts are proportional to the square of the motors rotational speed. A state-space model (kinematics and dynamics) is developed by physical laws. But, this deduced model presents several no linearities that are produced by three factors: the orientation (Pitch, Roll and Yaw), the control action and the angular velocities. To be able to control the quadrotor system in simple, linear and manageable way, it is necessary to linearize the system. Two method are possible: a classical linearization around several set-points and a multi-model linearization. In this case, a multi-model linearization is proposed due to the obtained control model will be used to compute a multi-model controller using fuzzy techniques. Fuzzy control techniques are suitable for linear parameter varying systems with no linearities, as our quadrotor.