Controller Design Of Uncertain Quadrotors With Transient-state And Steady-state Performaces Constraints

The quadrotor unmanned aerial vehicle is a new unmanned aerial vehicle with excellent performances.It is not only light and easy to carry,but also has low noise and strong concealment.It is widely used in military reconnaissance,map mapping,aerial photography and cargo delivery.However,in practical applications,on the one hand,the quadrotor is underactuated due to its special physical structure;on the other hand,its system model not only has nonlinear characteristics,but also is vulnerable to internal parameter uncertainties and external disturbances.In addition,the complex working environment and increasing performance requirements have put forward higher and higher requirements for the design of control system.This paper deals with quadrotor controller design problems in the case of external disturbances,uncertainties of inertial parameters,time-varying payloads and actuator saturation.The main research contents are as follows:(1)The tracking control problem with transient-state and steady-state constraints is considered for uncertain quadrotor system.Firstly,based on Newton’s law,the mechanism model of quadrotor system under time-varying payloads and wind gust disturbances is constructed.Then,the adaptive method and inequality scaling technique are used to address the uncertainties of control gain and inertia parameters.Finally,based on the recursive backstepping design method,an adaptive prescribed performance tracking control scheme is constructed,which makes the closed-loop system uniformly ultimately stable.And it ensures that the transient-state and steady-state processes of position tracking errors satisfy the preset constraints.(2)Based on the barrier Lyapunov function and recursive backstepping design method,the multivariable state constrained control strategy is constructed for the uncertain quadrotor system with partial state constraints.It ensures that the transient-and steady-state processes of state variables satisfy the preset constant constraints and time-varying asymmetric constraints,respectively.The effectiveness of the proposed control strategy is verified by numerical simulation and experiment results.(3)The tracking control problem under asymmetric time-varying full state constraints and asymmetric time-varying saturated input constraints is studied for the quadrotor system.Firstly,the mathematical model of asymmetric time-varying saturated input is constructed by a transformation function,and the original system with saturated input is transformed into an equivalent unsaturated system by utilizing the first-order auxiliary system.Then,based on this equivalent augmented system,the full-state constrained and saturated control scheme is constructed by means of a novel barrier Lyapunov function and a Nussbaum gain technique to ensure the stability of the closed-loop system,and the all state variables and input signals of the quadrotor system meet the preset constraints.(4)Considering the limitations of a single quadrotor system,based on the barrier Lyapunov function and dynamic surface technique,a distributed adaptive containment cooperative control protocol is proposed.By introducing a first-order lowpass filter,the derivative of virtual control is estimated to avoid the problem of "computational explosion" in the traditional backstepping method.In addition,in order to avoid the control input exceeding the constraints,an additional system is designed to compensate the input.Finally,the stability of closed-loop system is proved by barrier Lyapunov stability theory,and the containment errors meet the requirements of overshoot,convergence accuracy and convergence speed.