Design And Simulation Of Flight Management Computer System CDU Unit In Flight Simulation

CDU(Control Display Unit) builds relationship between operator and FMCS(flight management computer system) as a man-machine interactive component. CDU is an important part of flight simulator and plays an important part in flight. Pilot can build flight plan and modify route and set up performance parameter through the CDU keyboard and look up flight information through CDU screen.This paper has studied CDU from the shape of CDU, key function, display area and logic between pages and has analyzed the prepare work before flight and relationships between pages in flying, and has illustrated these relationships with flow diagrams. Then two simulation solution cases of CDU were proposed, and then chose one better after compared these cases. This better case adopted the method of combination hardware with software and divided the simulation system of CDU to three parts: CDU display terminal, main simulator program and BOX_CDU.The software of CDU display terminal was developed with EVC++ development tool, and aimed to finish mainly the acquisition of CDU key signal, the display of pages data, communication with UDP(user datagram protocol) and handling of special characters. The design of hardware was finished through the selecting the type of PC/104,48DIO and LCD display screen, and through making the CDU keyboard. The CDU keyboard was designed and manufactured according to imitation of physical CDU to increase simulation fidelity.The main simulator program is compared to software system framework in flight simulator. It communicated CDU display terminal and BOX_CDU as a kind of communication equipment in CDU simulation system. This part mainly analyzed encoding, decoding and transport of CDU key value and CDU pages data, and handling of CDU menu page creation and display of the sub-system. Furthermore, this part analyzed in detail the communication format of ARINC-429. Then, UML(Unified Modeling Language) was adopted to create the model of software system for the simulation system of CDU, and described the process with kinds of diagram. BOX_CDU is the core of simulation system of CDU. This part described the process of the software design from data interaction with navigation system, key function, data arrangement and data encoding. It aimed to finish mainly the creation and management of some pages data, the handling of key function and the display and handling of warning messages. The flow diagrams of program design were given.After experiment, this simulation case was verified feasible from the experiment results. The display effect of CDU and CDU keyboard meet the requirement of flight simulator for training or engineering. It has high fidelity to emulate the B737-NG series air plane. It provides a kind of concept or idea and basement for research on the simulation of CDU.