Control System Design And Implementation Of Quadrotor

Quadrotor is a kind of six degrees of freedom(DOF) multi-propeller aircraft.There are many advantages, such as the simple mechanical structure, flexibleattitude control, symmetrical propellers and vertical take-off and landing.Comparing with the traditional single-propeller helicopter, it’s more suitable for thetask of aerial photo, router inspection and near-earth flight. So it has been widelyapplied in the fields of military and civilian. Quadrotor is a typical under-actualsystem with six DOF and four controllable inputs. Because of its complex controlmethod, it has become a popular research inland and outland. This paper aims atbuilding a real control experiment platform of quadrotor, and conducting someexperiments with the platform.Firstly, the structure and dynamics characteristic of the quadrotor areresearched in the paper. The kinematics and dynamics model of quadrotor are builtby describing the helicopter with the Euler angle method. According to the PIDcontroller and the kinematics and dynamics model, the control architecture isdesigned. Four DOF are controlled including the roll Angle, pitching Angle, yawAngle and height. The attitude control and height system are established throughthe method mentioned above, and the effectiveness of control method is verified bythe simulation.Secondly, a complete set of experiment platform was established according tothe requirements of the quadrotor control system design. There are three parts in theplatform: the STM32micro-controller which is the control core, MPU6050whichcan measure the acceleration and angular velocity data, NRF24L01which isresponsible for the PC and the four rotor helicopter data communication as the datatransfer. And the PC platform is designed by using WPF framework to realize thehuman-computer interaction. Finally, in order to solve the problem of the micro-controller computingtrigonometric function with slow calculation speed, which is often appears in theprocess of the actual control, a new method is proposed in this paper. And the mainpattern of the method is converting the trigonometric function calculations to themultiplication by using the quaternion to describe quadrotor mode, which greatlyreduces the computational complexity. Therefore, the micro-controller can be usedto realize quadrotor attitude control.