Design And Study On Motion Control Strategy Of The Flight Simulator Stewart Platform

Flight simulator is a kind of mechanical and electrical equipment to train pilots,which can reproduce the flight state of aircraft in the actual environment to the greatest extent.Because of its low cost,safety and reliability,flexible use and other advantages,it is widely used in the world to train pilots and research aircraft.Flight simulator usually uses six-degree-of-freedom Stewart platform with high accuracy,good stiffness and large load-carrying capacity,but its motion space is relatively small.Therefore,it is necessary to use the washout algorithm to transform the actual motion signal of the aircraft into the signal that can be realized by the six-degree-offreedom Stewart platform.This paper mainly includes the design of the platform and the research of its control strategy.Firstly,according to the structural characteristics of the six-degree-of-freedom Stewart platform,the structural parameters are defined,the appropriate coordinate system is established,the inverse equation of the position and velocity of the leg is derived,the overall dynamic equation is established,and the special position of the platform which is prone to failure in the course of movement is analyzed.Secondly,according to the appearance,size,accuracy and overall stress state of the six-degree-of-freedom Stewart platform model,three-dimensional models of the upper motion platform,six upper hinges,six electric cylinder legs,six lower hinges and the lower fixed platform are established,and the overall assembly task of the platform is completed.After the establishment of the three-dimensional geometric model,it is imported into Adams to set parameters and validate the model.The platform is preliminarily optimized,and the spatial motion state of the platform translation and rotation is analyzed.Thirdly,according to the technical parameters of the six-degree-of-freedom Stewart platform,the three-dimensional model is optimized many times and the best design scheme is selected.According to the Adams simulation results of the six-degree-of-freedom Stewart platform,the overall structure of the platform is preliminarily designed,including the upper motion platform,six upper hinges,six electric cylinder legs,six lower hinges and the lower fixed platform.According to the general principle of 6-DOF Stewart platform design,the fault treatment and protection measures of mechanical system design safety,driving system safety,control system hardware safety,control system software safety are determined.Finally,on the basis of classical washout algorithm,an improved washout algorithm model is built by using MATLAB/Simulink module to improve the security of the platform and ensure that the platform simulation does not exceed its limited motion space.According to the input aircraft motion simulation signal,the attitude and position changes of the platform after the washout algorithm are analyzed,and the rationality of the improved washout algorithm is verified.