Quadrotor Dynamic Model

Introduction to Quadrotor Model

A quadrotor (Quadrotor) is a common unmanned aerial vehicle (UAV) structure whose flight principle relies on adjusting the rotation speeds of four propellers to achieve balance, hovering, and motion control. MATLAB serves as a powerful simulation tool that can be used to construct dynamic models of quadrotors, facilitating research into their flight characteristics or the design of control algorithms.

Core Modeling Approach

Dynamic Analysis The motion of a quadrotor primarily depends on the lift and torque generated by its four rotors. A six-degree-of-freedom (6-DOF) dynamic model is established using Newton-Euler equations, encompassing both translational and rotational motions. Key variables include: Position and Orientation: Typically described using 3D coordinates (x, y, z) and Euler angles (pitch, roll, yaw). Force Analysis: Includes gravitational force, rotor lift (proportional to the square of rotational speed), and aerodynamic drag.

Control Inputs and Coupling Quadrotors achieve control by adjusting the rotational speeds of four motors, for example: Vertical Motion: Synchronous increase or decrease in the speeds of all four rotors. Yaw Motion: Differential speeds between diagonal rotors generate counter-torque. The model must account for strong coupling effects (e.g., pitch maneuvers affecting horizontal displacement).

MATLAB Implementation Key Points Use ODE solvers (e.g., `ode45`) to simulate dynamic systems described by differential equations. Modular design via Simulink allows separation of the controller and model components. Linearized models (e.g., under small-angle assumptions) can simplify controller design.

Extension Directions Environmental Disturbances: Enhance model realism by incorporating wind disturbances or sensor noise. Control Algorithm Validation: Test the performance of PID, LQR, or neural network control strategies within the model.

Through MATLAB modeling, developers can efficiently validate theoretical designs before migrating them to actual flight control hardware.