The model reference adaptive control or MRAC is a direct adaptive strategy which consists of some adjustable controller parameters and an adjusting mechanism to adjust them. In the second, the plant model is parameterized in terms of the controller parameters that are estimated directly without intermediate calculations involving plant parameter estimates. In the first approach, the plant parameters are estimate online and used to calculate the controller parameters. Two different approaches can be distinguished: indirect and direct approaches. The adaptive control is an advance control technique which provides a systematic approach for automatic adjustment of controllers in real time, in order to achieve or to maintain a desired level of control system performance, when the parameters of the plant dynamic model are unknown and/or change in time. In Section 4, simulations and analysis are presented to verify the performance of MRAC schema, and finally in Section 5, conclusions of this work are presented. Section 3 provides brief introduction about the adaptive control theory and the methodology used is based to obtain the adaptive law equations.
This chapter is organized as follows: Section 2 presents the mathematical model of the quadrotor obtained using Newton-Euler equations.
The adaptive control permit deals with modeling errors and disturbance uncertainty, variations of the mass, inertia, actuators faults, nonlinear aerodynamics, etc. In this work, we develop an adaptive control strategy to stabilize the attitude dynamics of a quadrotor UAV.
We assume elastic deformations sufficient stiffness and realistic flight maneuvers were omitted, mass distributions of the quadrotor are symmetrical in the x-y plane, drag factor and thrust factor of the quadrotor are constant, and air density around the quadrotor is constant.
Flight control system for quadcopter full#
The dynamic behavior of quadrotor has been published in varying complexity particularly, the model we used is based on, where an extended mathematical description by the full consideration of nonlinear coupling between the axes is presented. Therefore, a suitable control system for stabilizing the closed loop control system is required to do this, various control techniques, linear and nonlinear, have been implemented such as control PD, control PID, control of position and orientation by vision, sliding mode control, fuzzy logic, and adaptive control in. Quadrotors are a kind of mini-UAV’s with vertical take-off and landing, controlled completed through four rotors mounted on each end of the crossed axes, which provide lift forces for the quadrotor move, this vehicle is very popular in the research community due to their special features like strong coupling subsystems, unknown physical parameters, and nonparametric uncertainties in inputs and external disturbances. In the last decades, advances in technology and costs reduction permitted to adopt this technology in civil applications such as aerial photography, video and mapping, pollution and land monitoring, powerline inspection, fire detection, agriculture, and among other applications. Since then, they are being widely used in military missions such as surveillance of enemy activity, airfield base security, airfield damage assessment, elimination of unexploded bombs, etc. However, it was not until the World War I that UAVs became recognized systems. In the 1883, an Englishman named Douglas Archibald provided one of the world’s first reconnaissance UAVs. One of the first applications of these vehicles was aerial photography. In the beginning, they were solely used for military purposes. Unmanned aerial vehicles (UAVs) are aircrafts that do not require a pilot on board to be controlled.
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