Research On The Integrated Control Method Of Variable Speed Helicopter/Engine Under Multiple Configurations

In order to meet the requirements of helicopter load,the design and development of a new generation of helicopters need to consider the configuration of multiple engines,and in order to improve the performance of the helicopter,the rotor speed needs to be controlled.For helicopters equipped with multiple engines,the difference of engine working state will seriously affect the life of the transmission system,so it is necessary to adopt appropriate control methods to match the output torque of multiple engines in real time.In this paper,from the perspective of integrated modeling and control of rotor/turboshaft engine,multiple matching of turboshaft engine is studied,and variable rotor speed control is studied.Firstly,an improved comprehensive model of rotor/turboshaft engine is established to simulate the dynamic operation of the same rotor driven by multiple engines.A rotor model based on leaf element method was established,Based on the volumetric dynamics method,the aerothermodynamics model of each component of the turboshaft engine was established,and the component level model of the turboshaft engine was formed through the simulation of working together.The simulation results show that the proposed model has good precision and convergence.Secondly,a torque matching control method for turboshaft engine with multiple configurations is proposed.Two methods of unilateral matching and bilateral matching are designed.Based on the three-engine turboshaft engine/rotor integrated real-time model,the two matching methods are simulated and compared.The results show that the proposed control method can quickly balance the output torque of three engines on the premise of satisfying the demand of rotor power.The matching time of bilateral matching of the same working point is shortened by more than 50% than that of unilateral matching,and the torque matching time of bilateral matching is significantly shortened,but the drooping amount of power turbine speed is slightly larger.As the cost of matching speed is acceptable.Next,the two methods of variable rotor speed control are compared,their advantages and disadvantages are analyzed,and the fixed transmission ratio scheme is adopted,in order to realize the continuous change of the rotor speed,this paper adopts the torque sequence transfer scheme.On the basis of the rotor/turbo-shaft engine integrated model under the dual configuration,the variable speed control of the two engines is carried out successively to finally realize the control of the rotor speed.The digital simulation test of torque sequence transfer control is carried out.The simulation results show that the relative speed of the two turboscopic engines can be reduced from 107.5% to 92.5% at both ground height and high altitude,and the rotor speed can be reduced from 107.5% to 80%,and the overshoot of the power turbine speed can be controlled within 3% in the variable speed process.Then,the timing sequence transfer control simulation is carried out under the three-shot state.The simulation results show that the timing sequence transfer control can still achieve the large range change of rotor speed under the multi-shot state.Finally,with the aid of the hardware in-loop simulation platform,further simulation experiments were conducted on the proposed rotor/turboshaft engine integrated model and torque matching control method with single-engine ? dual-engine and tri-engine configurations.The simulation results showed that the established model also had good real-time performance and robustness in the hardware in loop simulation platform.