1 Nonlinear sliding Mode Controller for Quadrotor With effect noise disturbance Mohammad Reza Soltanpour 1 , Sepehr Sigari Hamedani 2 1 Department of Electrical Engineering, Shahid Sattari Aeronautical University of Science and Technology, Tehran, Iran Email address: soltanpour@ssau.ac.ir 2 Department of Electrical Engineering, Damavand science and Research Branch, Islamic Azad University, Damavand ،Iran Email address: Sepehrsigari@gmail.com Abstarct Quadrotor is one type of UAV for which a non-linear control model has been designed due to quadrotor in this paper. In this article, firstly the manner of quadrotor’s movement has been discussed, and then quadrotor dynamic model and rotational equations which are based on the Newton Euler method have neen investigated. Moreover, quadrotor torques, transfer equations, and state space have been investigated. In this study, 6 degrees of quadrotor freedom has been explored and compared by using two controllers 1) PID controller and 2) sliding mode controller (SMC), including behavior and quadrotor altitude. Control model for quadrotor not only controls the three controllers of quadrotor act, that includes rotation around the axis (X, Y, Z), but also controls one controller of quadrotor altitude. In the next part, two controllers of disturbance have been added to control systems. Finally, the flight path would be continued by the Sliding Mode Controller (SMC) in spite of disturbance. Keywords: Quadrotor, Sliding Mode control, PID, Disturbance, Flight path 1. INTRODUCTION Simultaneously with the development of science , technology, especially in the aerospace, industry requires the use of automatic control devices that are known to drones. More specifically, according to various applications and unique features, the desire for research and development in the field of quadrature control increase day by day. Quadrature for aerial surveillance, identification, and inspection is complicated and perilous amount of work in a wide range of environments is required. Quadrotor has a high order and multivariate non-linear system with six degrees of freedom and four motors .Quadrotors include several engines and rotors, a body, sensors and electronic boards, which have been designed during a complex process. The required force to make the quadrotor fly is generated through transferring engine power to the propellers. The nonlinear dynamic model of the quadrotor is formulated using the Newton-Euler method. The formulated model is detailed including aerodynamic effects and rotor dynamics that are omitted in much of the literature. The motion of the quadrotor can be divided into two subsystems; a rotational subsystem (attitude and heading) and a translational subsystem (altitude and x and y motion). The quadrotor is a six DOF underactuated system. The derived rotational subsystem is fully actuated, while the translational subsystem is underactuated. These fly robots being dynamically unstable, in order to be stabilized, need artificial stabilization system. To design the control system, a processor, three Giroud sensors, and a motor speed controller will be required. A quadrotor is an aerial vehicle with four rotors arranged in a symmetric, square configuration around a central hub, which houses the battery and processing components. The quadrotor propellers are not all alike. In fact, they are divided in two pairs, two pushers and two puller blades, that work in contra-rotation. As a consequence, the resulting net torque can be null if all propellers turn with the same angular velocity, thus allowing for the aircraft to remain still around its center of gravity. To change height, it is enough to increase or decrease the rate of each of the four rotors at the same time. Also, to perform a stationary hover, all four rotors should rotate at the same rate. Since both pairs of rotors spin in opposite directions, the net torque on the craft resulting from the drag of the propellers equals zero. 1.1 Discribe Quadrotor moveing a) In this case, motors 2 and 4 with constant speed (average speed) are spinning and motor 1 is rotating faster than motor 3 that makes quadrotor move backward.