Design And Trajectory Planning Of A Four-DOF Flight Simulator

Flight simulator is a ground device,which is able to simulate all kinds of flight condition.In modern pilot training and daily entertainment,flight simulator is very necessary.In China,development based on flight simulator starts late.Meanwhile,the differences of technology level are large compared with other foreign country.At present,our flight simulators' market relies much on import.This article,aiming at the disadvantages that parallel flight simulators have small workspace,difficulty in calculating kinetics and dynamics,and complex control system,designs a four-DOF series flight simulator and works on some important technologies including following aspects:Firstly,based on the research situation of domestic and international flight simulator,performance index and general design scheme of a 4-DOF flight simulator was put forward.Transmission and driving systems of each joint were also determined.Then according to these joints' technical indicators,we designed mechanical structures and studied key parts with finite element analysis,proving that it satisfies the stiffness and strength requirement under full load.Secondly,we studied the flight simulator's kinetics.Based on the D-H model,we calculated its kinematical equation.Forward kinetics was shown by RPY model according to the simulator's special structure.Then we used Monte Carlo method to compute and analysis the flight simulator's workspace and made a simulation,providing theoretical basis for control system designing.Thirdly,control system was designed from both hardware and software.After showing an overview strategy,we made detailed analysis and introduction on main hardware device choice,and designed their connection and composition.Then with soft PLC,using CodeSys to realize the flight simulator's main function,we finished a HMI for debugging.Next,a model machine was built and used to examine its mechanical structure and control system's feasibility,and system response's timeliness by experiment.It was proved that the 4-DOF flight simulator we designed is reasonable and workable.Finally,since the simulator may shocked badly during moving,its trajectory was optimized using genetic algorithm and piecewise cubic splines,limiting each joint's angle velocity,acceleration and jerk,aiming at time and impact,we optimized the flight simulator's joint path based on fixed time and minimum jerk to get less vibration and impact so that the machine's life could become longer.Experiment proved that our method is correct and feasible.