Design And Airworthiness Research On Automatic Flight System Modes Of Civil Aircraft

Automatic Flight System of Civil aircraft is one of the most important systems for the large commercial aircraft.The pilot can select different modes in order to perform the flight mission.Civil aircraft must pass the airworthiness certification to check whether it meets the requirements of airworthiness regulations before it comes into service.Due to the highly development of computer software and hardware,it becomes possible to conduct airworthiness designing and compliance verification for working modes of automatic flight system based on the desktop simulation platform.This article will study the mode design of civil aircraft automatic flight system and its airworthiness.The main work is as follows:Firstly,the airworthiness regulations and industry standards for the design of automatic flight system at home and abroad are summarized,and their design requirements are analyzed,including functional,safety,flight quality indicators and so on.With reference to RTCA/DO-178 and RTCA/DO-325 documents,a reasonable and effective method of compliance verification is put forward to provide ideas for airworthiness verification of airborne software.Secondly,the finite state machine theory is analyzed.The state machine model is applied to the automatic flight system,and the state input / output in the Mode Transition Logic is mapped into the automatic flight system.The automatic flight systems of two types of aircrafts are analyzed,which include mode,mode function,turn on-off conditions,and theirs finite state machine models are drawn as well.The theory lays the foundation for the mode design of desktop simulation platform in the following chapter.Thirdly,the article designs airworthy aircraft automatic flight system modes,including lateral mode,vertical mode,multi-axis mode and auto-throttle with its multiple sub-modes.It defines the functions of each mode and connection-disconnection conditions,including the mode switching conditions.Finally,a desktop closed-loop simulation platform is set up.By using MATLAB/Stateflow language and linking with the flight dynamics model,a suitable human-computer interaction interface is designed for vertical flight,lateral flight mode and approach landing flight simulation.The experimental results show that the designed finite state machine model can realize the automatic transition of mode functions and modes to meet the experimental requirements.The conclusion can provide a research idea for airworthiness design of automatic flight system mode.