Design And Implementation Of Finite-time Adaptive Sliding Mode Controller For Twins-rotor Aircraft

Aircraft has the characteristics of strong maneuverability,fast response speed and good dynamic quality,and has been widely used in all aspects of social life.Attitude control is one of the key issues for aircraft control.Model uncertainties and external disturbances in aircraft systems may seriously affect the stability and control accuracy of the aircraft attitude control system.For a twins-rotor aircraft system with model uncertainty and external disturbances,a finite-time adaptive sliding mode controller is designed to improve the attitude control performance of the aircraft.The main research contents of this article are as follows:(1)Aiming at the problem of attitude tracking of twins-rotor aircraft with disturbance and uncertainty,a finite-time adaptive control strategy based on fast terminal sliding mode is proposed.Construct a fast terminal sliding mode surface and use continuous quadratic functions to avoid singular value problems.A finite-time controller is designed to ensure the finite-time convergence of the system's attitude tracking error.The parameter adaptive law is designed to realize the estimation and compensation of the upper bound of uncertain interference.Lyapunov stability analysis proves that the attitude tracking error can reach a uniform and bounded state in a limited time.Finally,the effectiveness of the proposed control strategy is verified by numerical simulation and experimental platform of twins-rotor aircraft.(2)In order to improve the steady-state tracking accuracy of the twins-rotor aircraft,a compound finite-time adaptive sliding mode control strategy is proposed.By adding the integral term to the finite-time sliding mode surface,a composite finite-time sliding mode surface is constructed,and the convergence process of the error variables is analyzed.A finite-time adaptive controller is designed,and the finite-time convergence of sliding mode variables and attitude tracking errors is proved by Lyapunov stability theory.Finally,the effectiveness of the proposed control strategy is verified by numerical simulation and experimental platform of twins-rotor aircraft.(3)In order to solve the problem that the convergence time depends on the initial conditions in finite-time control,a compound fixed-time adaptive sliding mode control strategy is proposed to ensure that the state variables of the twins-rotor aircraft converge within a fixed time,and the upper bound of the convergence time and the system The initial state is irrelevant.Construct a fixed time sliding mode surface to ensure that the sliding mode variables converge within a fixed time.A fixed-time controller is designed to ensure that the attitude tracking error converges to the neighborhood of an equilibrium point within a fixed time.Based on Lyapunov's theory,the stability of the closed-loop system is proved,and the effectiveness and feasibility of the proposed control strategy are verified by numerical simulation and the experimental platform of a twins-rotor aircraft.