Research On Flight Attitude Control Of Four-rotor Unmanned Aerial Vehicle

The four-rotor unmanned aerial vehicle,which is one of the rotor unmanned aerial vehicles,is a new ultra-small aircraft in recent years.With the continuous development of science and technology,as well as the emergence of micro-electromechanical,micro-navigation technology,four-rotor unmanned aerial vehicle has developed into a new era.Thus,many countries have set up a relevant research institutions to start the research.Four-rotor unmanned aerial vehicle is an emerging ultra-small aircraft in recent years.It has many advantages such as high control flexibility and strong anti-jamming capability.It also has great potential practical expectations in civil aerial photography,military terrain reconnaissance and industrial power line detection.But the four-rotorcraft system has the problems of lack of driving ability and multivariable factors,which makes it become a national and international hotspot and difficult problem in the field of automatic control.First of all,the structure and working principle of four-rotor unmanned aerial vehicle are analyzed,and the system hardware design of four-rotor unmanned aerial vehicle is established in this paper.The flight attitude control of four-rotor unmanned aerial vehicle is researched by using STM32 as the flight controller.The accelerometer and gyroscope,geomagnetic sensor and barometric pressure sensor are used as attitude and position feedback devices.The signal is transmitted through Bluetooth controller.Quaternion method,Kalman filter method and positional PID control algorithm,are used to design flight four-rotor unmanned aerial vehicle attitude controller.Secondly,after the hardware part of the design is completed,the aircraft software architecture began to be integrated design.In this paper,by analyzing the motion principle of four-rotor unmanned aerial vehicle,the nonlinear motion equation is deduced and simplified.Four control quantities are introduced and the nonlinear model is decoupled into four independent control channels.Using positional PID control algorithm,the flight test of four-rotor unmanned aerial vehicle is completed,and the feasibility of the flight attitude control is verified.Finally,the installation and commissioning of the aircraft,divided into indoor and outdoor testing.The main purpose of the indoor test is to fine-tune the parameters,so that the aircraft has the best attitude control.And then add high control channel test parameters,increase the height control function.To ensure safety,the test process uses a two-stage fixed high mode to ensure a high degree of control.Outdoor flight test position control debugging process using the fixed point mode.The optimal attitude control of the aircraft is adjusted by the method of fine tuning parameters in the process of test.In addition,the feasibility of the flight attitude control of four-rotor unmanned aerial vehicle is verified the addition of the height control channel test parameters.