A Design Of Testing System On Landing Gear Control Unit Of Aircraft

The landing gear is a very important part of an aircraft,whether it works normally concerns the air safety of the aircraft.Large aircraft landing gear has three control unit in general such as retractile control unit,brake control unit and nose wheel control unit,which control the landing gear system.These control units must be tested on earth before they installed on aircraft to ensure its function.This study aimed at designing a landing gear control unit testing system that is used to test the function of a type aircraft’s landing gear control unit on earth to guarantee the aircraft flying state.The control units that receive signals such as wheel speed,pressure and position from many sensors and connect with electromechanical management system by many communication methods output control orders to the controlled objects when they run normally.But the control unit won’t connect to the real aircraft when it is tested on earth.Consequently,according to the testing task,this study put a method that simulating the sensors’ signal to active control units and detecting the signals sent by control units through the way that combine the hardware and software,add PCI card and design extra circuits under control of the computer program to finish the testing task.This paper introduces the development of the testing system on the following steps:Make simplified introduction of the signals of every control units and then introduce the whole scheme.Selecting IO cards according to the signals’ characteristics and designing conditioning circuits to simulate the real sensors and detect the control units.On the base of hardware,designing testing program to test the control units.Preliminary testing the landing gear control units’ function.This study finished the development and production of the testing system,and met the requirements through the primary tests phased,which ensure the landing gear safety before it installed on aircraft.