Platform Design And Control Method Research For Small Quadrotor

Quadrotor, as a kind of Multi-Rotor Aircraft, have the characters of small volume and low cost. It occupies less space when it takes off and lands and it can maintain its excellent flight performance when facing complex space environment. So it has been more and more widely used in the civil, military and scientific research. With people’s interest to it, the establishment of quadrotor mathematical model, the construction of its software and hardware platform, the research of attitude measurement and control method attract more and more attention.Firstly, the mathematical model for quadrotor is established based on Newton’s second law and the law of rigid body rotation. The mathematic mode for quadrotor includes kinematic model and dynamic model, and it is divi ded into two inspects of attitude and position. The Euler angles and quaternions are used to represent the attitude. The force / torque the quadrotor receives in flight is analyzed, and then we select the appropriate physical quantity as the control input and build the mathematical model in combination with the analysis of flight principle.Secondly, the quadrotor platform is constructed using high performance MEMS sensors and STM32 processor. We focus on the design of the control board which is the core part of the quadrotor platform. And the selection of the processor, MEMS sensors and other peripherals are considered as well as the circuit design of core system.Then, after being corrected and processed by low-pass filter, the sensor data is fused by means of interpolation method, complementary filtering method and gradient descent method to measure quadrotor attitude. This text introduces the working principle of the accelerometer, gyroscope and electronic compass to measure the attitude information, as well as their shortcomings. And use the methods above to get accurate attitude information.At last, we design an adaptive sliding mode control method based on state observer to control the quadrotor attitude. In the text, the control of quadrotor is divided into two parts: inner loop control and outer loop control. The inner loop control is for attitude control and outer loop control is for position control. Compared with PID control, the sliding mode control method has better response speed, control precision and robustness.