Study On The Control Of Torsional Vibration Suppression Of Turbo-shaft Engine

In order to further enhance the maneuverability and safety of the helicopter,active vibration control has been paid more and more attention in helicopter technology research,among which active control of torsional vibration of the engine is one of the major branches.The torque transmission chain of the helicopter system connects the engine,the rotor,the tail rotor and other accessories,thus the power of the engine can be provided to the rotor.However,the torsional vibration severely affects the safety and effectiveness of the helicopter transmission mechanism and its control system,and the operation of the pilot will also be affected.In that case,serious flight safety accident will even be caused.Therefore,it is very important to develop research of the integrated torsional vibration model of the helicopter and the design of the torsional vibration suppression method.Firstly,based on the physical model of the torque transmission chain,a simplified torsional vibration model of the helicopter including rotor,hub,transmission system,engine and fuselage is established.The simplified model can accurately simulate the real-time torque transfer process.The physical characteristic of the model is solved and simulated.Then,combined with the pneumatic thermodynamics model of the turbo-shaft engine/ rotor,the integrated helicopter/ transmission/ engine torsional vibration model is established.The simulation results show that the integrated helicopter/ transmission/ engine torsional vibration model can be used to simulate the torsional vibration dynamics of the helicopter,transmission and engine at different maneuvering flight.And the torsional vibration process,the aerodynamic thermodynamics characteristics can be reflected.Secondly,for the first-order torsional vibration mode,a constant coefficient notch filter is designed to suppress the torsional vibration signal at the engine.On this basis,the algorithm with adaptive torsional vibration filter function is proposed and designed.The algorithm combines the Fast Fourier Transform(FFT)with the search algorithm to suppress the torsional vibration at the engine end for the maneuvering flight and the variable rotor condition.The simulation results show that the designed adaptive filter can suppress the variable frequency torsional vibration signal in real time and have the engineering feasibility.Finally,an engine predictive controller based on supported vector machine is proposed and designed.Based on the helicopter model,the control variables are optimized by rolling iterations,the power following capability of the engine is enhanced,the sagging amount and the overshoot amount of the free turbine speed are reduced,and the parameters of the turbo-axis engine with torsional vibration characteristics are established.Not only the the torsional vibration is suppressed,the turbo-shaft engine fast response to high quality control is realized.