Research On Quantitative Feedback Design Method Of Hydraulic Flight Simulator

Hydraulic flight simulators are sets of high-tech equipments with important significance of economic value and national defense, and are usually used in hardware-in-the-loop simulations with massive and large-scale unit under test (UUT) subject to high accelerations. They can simulate flying posture and dynamic characteristics of flight vehicle to test the performance of sensors, control system and actuators in the lab, and provide reference to flight vehicle designers. Their performances decide the motion fidelity of flight simulation results. During the design of hydraulic flight simulator, dual hydraulic motors direct driven scheme is adopted in gimbal design to maintain symmetry of load and structure of gimbal, and improving structure stiffness of gimbal. The application of this driven scheme improves flight simulators'performance, while arises problem of dual hydraulic motors synchronization control. Therefore, it is meaningful to learn the interaction mechanism models and synchronization controller design methods of dual hydraulic motors synchronization driven system of hydraulic flight simulator under different synchronization control scheme.After synthesizing numerous related literatures and reference materials at home and abroad, the paper overviews current situation of hydraulic synchronization control techniques researches and their basic control principles, and outlines advancement of closed loop synchronization control strategies and quantitative feedback theory (QFT). The main study direction and content are decided based on mentioned materials.The paper builds the interaction mechanism models of dual hydraulic motors synchronization driven system under different synchronization control scheme. Closed loop synchronization control transfer function matrices with and without mechanical coupling under equal status, cross coupled and master slave synchronization control scheme are deduced on the basis of dynamic mathematical model of dual hydraulic motors synchronization driven system built earlier. During modeling of cross coupled synchronization control system, its stability verification conditions are obtained from quantitative feedback theory MIMO system stability theorem. Transformation equations of synchronization error between time domain indices and frequency domain indices are also deduced.Quantitative feedback design(QFD) methods of controllers based on data model and parameterized model and indirect closed loop identification method with power spectrum estimate are proposed in this paper to deal with controllers design problem of flight simulator single channel servo system. Controller QFD method based on data model gets given operating point extent data models through power spectrum closed loop indirect identification method, and use QFT design method to implement controller design. Experimental results indicated that the method can realize exact parameters tuning of controller that satisfy system performance indices. Controller QFD method based on parameterized model implements controller design with maximum and minimum uncertainty bounds of system frequency characteristics. Simulation results reveal that controllers designed with parameterized design method can satisfy system performance indices over whole given operating point extent.The paper proposes synchronization controller quantitative feedback design (QFD) method to synthesize flight simulator dual hydraulic motors synchronization controllers based on parameterized model and data model. Synchronization controller QFD method based on parameterized model synthesizes synchronization controllers of system under equal status, cross coupled and master slave synchronization control scheme. Simulation results indicate that equal status and cross-coupled synchronization controllers can fulfill strict performance requirements of flight simulator, while master slave controller can only satisfy synchronization error index. Synchronization controller QFD method based on data model synthesizes synchronization controllers of vertical hydraulic flight simulator under equal status and cross-coupled synchronization control scheme.Experiments are carried out on three-axis flight simulator middle gimbal with designed equal status and cross-coupled synchronization controllers. Frequency bandwidth, synchronization error and low speed performance indices are verified respectively with equal status synchronization control system and cross-coupled synchronization control system. Experimental results indicate that frequency bandwidth and low speed performance requirements can be both satisfied under two control schemes, while synchronization error index is exceeded but still acceptable. Meanwhile, comparison of parameters between controllers used in experiments and designed controllers reveals that synchronization controller QFD method can also realize exact parameters tuning of synchronization controllers.