On Performance Improvement Of Flight Simulation Turntable Via ESO

The active disturbances rejection control(ADRC)is a control strategy that does not depend on accurate model and has strong anti-disturbance performance.It observes the total disturbances of system through the extended state observer(ESO)and compensates the system as standand model with the series integral form.Within this framework,the observation accuracy for disturbance of ESO determines the effect of the compensation.However,when applying the classical ESO on the simulation turntable,the total disturbance amount is overlarge duo to large differrence between turntalbe model and series integral model,which limits the anti-disturbance performance of ESO.Aiming at improving the anti-disturbance performance of flight simulation turntable,available model of turntable is employed to modify the structure of the classical ESO.Furthermore,a performance improvement scheme for simulation turntable is proposed by combining ESO with traditional frequency domain control mothod.Series of analysis and improvement are conducted to solve some problems that appeared in practical application of ESO.The main aspects are given as following.Firstly,the structure and mechanistic model of the simulation turntable are given.Model perturbation and external disturbances in actual system and their effect on system performance are analyzed in detail.Then,the reasonability of applying the ESO to improve the anti-disturbance performance of turntable is illustrated.Secondly,to solve the problem that blindly compensating the plant as a series integral system may result in overlarge disturbance compensation,considering that the nominal model of turntable is available,a fourth-order ESO is designed.The observation performance and compensation effect of the disturbance is improved through this fourthorder ESO.And its superiority is sufficiently verified by plenty of comparisons and simulations.Thirdly,the ESO parameters tuning method based on the observation bandwidth is studied.For better ability of bandwidth expansion and noise suppression,a fourth-order Chebyshev filter is employed to tune the fourth-order ESO parameters.Through comparing with the traditional pole-placement method,the superiority of the method in disturbance observation and compensation is verified.Furthermore,in view of compensation performance decrease of the fixed parameter ESO caused by the nonlinear effect or load changes in actual application,an on-line parameter optimization strategy of ESO is designed.Through designing the evaluation function,constructing the extremum relation,a key parameter online optimization algorithm of ESO is designed based on the sliding-mode extremum seeking control(SESC).The simulation results sufficiently verify the effectiveness of proposed algorithm in solving above problems.Finally,for facilitating the engineering application,the above algorithms are programmed,and the corresponding ESO aided design software is developed.The performances of the software and algorithms are verified through the successful application on a real two-axis simulation turntable.Through comparative experiments under different working conditions,the superiority of the proposed ESO in the application on turntable is further verified compared with the classical ESO.More importantly,the experimental results show that the proposed method can greatly enhance the adaptability of the turntable to large changes of load inertia.