Force-feel Cueing Study Of Hydraulic Control Loading System Of Flight Simulator

It's very important for the aviation cause of our country to independently manufacture high level FS (Flight Simulator). CLS (Control Loading System) is one of the essential subsystems of FS, so high fidelity CLS is the presupposition for manufacturing high level FS. The method for fore-feel cueing applied to CLS, which is the theoretical foundation for developing high fidelity CLS, refer to a kind of servo control means by which the forces is provided to control lever of FS realistically replicating the forces that the pilot experiences during flight.Force feel simulation method is one of the vital techniques of CLS and, further, the dynamic force simulation and inertia compensation are the difficulty of CLS especially. In addition, The study of control strategy is very significant to CLS, by which the potential of CLS could be exerted sufficiently and the fidelity of force feel simulation could be further increased. Thereby, those issues of force feel simulation method, dynamic force replication, inertia compensation and control strategy of CLS are discussed in this thesis.The technique of dynamic force replication is very important to CLS and difficult to put in practice. The method studied in this thesis could simulate dynamic force feel, because the simulated object, which is a simple mechanical FCS (Flight Control System), is represented with a second order mass-spring model involved dynamic force such as inertia force and damping force. Consequently, the core of this subject is to study the method of force-feel cueing, but not only the three of main force-feel cueing method but the feedforward one or the robust control one could all be competent for dynamic force replication.The three of main force-feel cueing method of CLS are position-loop, velocity-loop and force-loop based control loading architectures, and the main issues of those methods are the principle of force-feel cueing, simulation model structure, stability problem and the vital parameters and its design requirement. At first, the three of control loading architectures are presented and the mathematic models of CLS are built up. Then the relation between the pilot force and the control motions is derived out from those models, which illuminated the principle of force-feel cueing, that is the relation could be adjusted by modifying simulation model, which results that the control motions and the pilot force inputs in the simulator could be the same as in flight. Then, making use of the equivalence relation between simulator and airplane, the simulation model is achieved, which is reasonably simplified for the sake of engineering implement. Third, stability of the inner loop and the outer loop is analyzed in all kind of CLS, which not only illuminates how the outer loop comes into being but opens out stability factors of the outer loop, and the stability conditions are put forward. At last, after analyzing force-feel cueing principle, developing the simulation model and discussing stability issues, three vital design parameters are pointed out, which are load inertia, load stiffness and band width of the inner loop. The design requirements of those parameters are brought out according to dynamic performance and stability of CLS also. To preliminarily prove those analysis conclusions, computer simulation of the three of force-feel cueing method is performed by a simulation model of CLS established in this thesis.The inertia compensation technique is very important to CLS in some case, especially when to develop low cost simulator of light airplane. A new inertia compensation method is developed in this thesis, that is, in the force-loop based CLS, the parameter of the simulation model inertia is evaluated to a negative value, and then the inertia of CLS could be compensated successfully. Using the method, smaller inertia force-feel could be replicated with a bigger load inertia CLS. The application condition of the inertia compensation is put forward also, and experiment results show that the method is effective.A model-based feedforward controller, which could enhance stability, are designed and applied to position-loop based CLS. In addition, according to the frequency characteristics test result of the servo mechanism, a force feedback controller to enhance stability is designed also. To improve the robust performance of CLS, A two dof robust control system architecture is put forward, and a robust controller is obtained using synthesis theory. Experiment results show that all the controllers designed in this thesis are effective.At last, the stability test, the step response test, the frequency response test and the superfluous force test are carred out on the CLS developed in this thesis, which prove out the analysis conclusion and validate all the designed controllers.