| The large civil aircraft is one of the major research projects in China’s long-running development plan,and it plays an important role in improving Chinese science & technology.This paper is supported by the large civil aircraft scientific research fund of national "Thirteenth Five-Year Plan",which is focus on the key issues in assisted piloting flight control of the large civil aircraft.The objective is to study on assisted pilot control methods for the large civil aircraft,to simulate and verify the assisted pilot control systems,and to analyze the flight quality evaluation of the assisted pilot control system.The main works in this paper are as follows:1.An assisted pilot control model of the large civil aircraft is established,which mainly includes three parts: a large civil aircraft dynamics model,an assisted pilot controller,and an active side stick servo control system.Considering the model of the B747-100/200 large civil aircraft,this paper used the relevant knowledge of rigid body dynamics to establish a general non-linear dynamic model of the large civil aircraft,and by using the Jacobian linearization method and the principle of small disturbance,the non-linear model is approximated and decoupled into the longitudinal and lateral linear models.Finally,the parameter identification method is used to construct a civil aircraft linear parameter varying(LPV)model.Using the principle of robust control of linear parameter timevarying systems,the civil aircraft assisted pilot control law is designed under the conditions of stall and low energy,and the civil aircraft assisted pilot control system is established according to the control configuration.Using the robust control principle,the active side stick servo control system model is established,which includes an active side stick dynamics model and a robust control system.2.The switching strategy of the aircraft assisted pilot control system is proposed.In order to ensure the robust stability and servo tracking performances of the civil aircraft with the large-scale variation in its fight parameters caused by pilot incorrect manipulations,the following work is carried out:a)A LPV control based design method is proposed for the aircraft assisted pilot control system to ensure the robust stability of the control system;b)Considering some emergency flight scenarios for example,for the high angle of attack with stall scenario,a safe-enhanced switching control system via LPV control strategy is designed.Simulation results show that it can improve robust stability and robust performances of the large civil aircraft in presence of large-scale changes of aircraft flight parameters resulted by pilot incorrect manipulations.They also show that the aircraft could be recovered from abnormal conditions,and enhance the aircraft’s safety performance has been enhanced.3.The simulations of the large civil aircraft assisted pilot systems have been carried out through the robust control method with parameter scheduling,and the tracking performances are demonstrated by comparing of H∞ robust control method with LPV control method are compared in the time domain.4.Using the bandwidth criterion,CAP criterion,and lateral frequency damping ratio criterion,the flight quality of the LPV control method at different operating points is analyzed,and the flight quality are compared with the controller based on H∞ robust control method.Through the above research work,this paper obtains a large civil aircraft assisted pilot control system;the robust control method with gain scheduling is used to solve the problem of assistance/automatic recovery control under high angle of attack with stall and low energy,etc.abnormal situations;The bandwidth criterion,CAP criterion and lateral model frequency damping ratio criterion are used to compare and analyze the flight quality of the assisted pilot control system. |
