Research On Flight Dynamics And Control Of Rotorcraft With Independent Control Of Six Degrees Of Freedom

Traditional multi-rotor aircrafts can't move with its attitudes hold or change attitudes with positions hold.This is because its translational velocities and positions are controlled indirectly through its attitudes control.For this reason,traditional multi-rotor aircrafts have limited adaptability and interactivity with narrow and complex space environments.In this thesis,the flight control problems of a quadrotor aircraft which can motion independently in any degree-of-freedom of its body is studied,focused on its optimal trim characteristics and optimal control law in transient transition flight in the perspective of minimum energy consumption.Firstly,the flight dynamics model of the quadrotor is established by using theories and methods of multi-body dynamics and rotor aerodynamics.In order to simulate the energy consumption characteristics more realistically,the influence of the vertical motion speed of the rotor relative to the air on the thrust and the required power is considered in the aerodynamic modeling of the rotor.On this basis,the balance equation of the aircraft in any hovering and flying state is established.Targeting the characteristics of over-driven and under-determined systems,with the goal of minimizing energy consumption,and the optimal trim is obtained under different attitudes and different speeds.The balance calculation calculates the control law of the minimum equilibrium state of energy consumption and the balance between force and moment.Then,based on the optimal control theory,the nonlinear mathematical programming method is used to numerically analyze the minimum energy consumption control law of the fixed-speed variable attitude and the fixed attitude variable speed transient process,and the optimal Manipulation and movement laws of the aircraft is summarized.Finally,the optimal control law of energy consumption is used as the feedforward Manipulation input,and the transient process of fixed-speed variable attitude and the fixed attitude variable speed is simulated.By comparing with the simulation of conventional PID feedback control,The minimum energy consumption characteristics of the optimal control law under independent motion of attitude and velocity are verified.