Research Of Quad-Rotor Aircraft Attitude Control Based On Fuzzy Adaptive PID

In recent years,the quad-rotor aircraft has received extensive attention.For its many fine characteristics,it has been widely used in military,civil and commercial fields,which has a good application prospect.But it is undeniable that the quad-rotor aircraft is a very complex nonlinear system,which needs to to control a lot of variables with strong coupling,and is vulnerable to the uncertainties of the external environment and internal parameters of the system during the flight.These factors make it difficult to design the control system of the quad-rotor aircraft.Traditional fuzzy PID control is hard to choose a suitable quantitative factors and proportional factor,which often be blindly chosen by their own subjective judgment or experience.When the output error becomes smaller and smaller,the use of fixed quantitative factors and proportional factor will make the control rules get closer to zero with fewer available control rules,which is hard to adapt to a variety of different environments,and achieve the desired control effects.In view of this,a factor adaptive fuzzy PID control method is proposed by finding out the relations between the quantitative factors and the proportional factor with the error and the error change rate based on the theory of variable universe to scale the fuzzy domain,which can make the quad-rotor aircraft can be matched with different quantitative factors and proportional factor in different stages of operation so as to further improve the attitude control performance of the quad-rotor aircraft.The specific research contents are as follows.(1)The research background and significance of the attitude control of the quad-rotor aircraft are introduced,then the status of the research on the attitude control of the four rotor aircraft at home and abroad are analyzed,then the performance and characteristics of several common attitude control methods are introduced as well,which as a basis of the proposed factor adaptive fuzzy PID control method.(2)Several different motion states of four-rotor aircraft are analyzed,the transformable relationship between the body coordinate system and the ground coordinate system is determined,and the Euler equation is adopted to study the translational and rotational models of the quad-rotor aircraft so as to obtain the nonlinear dynamic model of the quadrotor aircraft.(3)According to the built nonlinear dynamic model of the four rotor aircraft,a factor adaptive fuzzy PID control method is proposed,which changes the input and output domain size by introducing two on-line adjustable scale change factors.It is ensured that the system can be controlled by more fuzzy rules when the error amount is very small during the whole regulation process.Then a simulation analysis is carried out through matlab.The simulation results show that the proposed adaptive Fuzzy PID control method is effective,and is better when compared with the other two control algorithms.(4)Based on the analysis of Attitude control theory and simulation experiment,the effectivity of the proposed algorithm is verified by combining with the physical platform.In KEIL5 integrated development environment,the proposed algorithm is implemented by coding the relevant program.to complete the attitude control of the quad-rotor aircraft.The test results show that the proposed algorithm can effectively accomplish the attitude control of the quad-rotor aircraft.