Aircraft Instrument Test Bed Design

ATE plays a more and more important role in the test and repair of aircraft avionics, and can considerably improve servicing quality and efficiency.Our task is to develop a new type of ATE used to test six kinds of aircraft avionics instruments located in the cockpit. It should be able to fulfill the test of all functions and performances of each instruments according to it's Component Maintenance Manual. This ATE has been achieved and proved useful. We named it as 'ATE 8000 Avionics Instruments General Tester'.In this paper we described in detailed its design intention , method and realization of the hardware and software. Firstly, we introduce some conception and general design theory of ATE, then we analyze the construction and signal forms of these instruments, especially on its main functional block , servosystem's working principle and signal form. According to different signal forms , we plan for the execution methods of three test items :servosystem performance, discrete signal input ,discrete signal output., and decide the necessary modules which this ATE is composed of .In this research project we designed some special modules such as synchro/resolver signal transmit & receive card, discrete signal output comparison card ,ADI and HIS adapter cards ect. The synchro/resolver signal transmit & receive card is the most important and difficult part which used special A/D and D/A (axis angle converter ) to make conversion between the analog singnals related to angle and its digital counterpart ,thus solve the issue of stimulation and test of synchro/resolver signal ,improved the test precision and automatic degree.As to the software, we firstly scheduled all of the test signal path between the computer and the UUT , the output control logic between the digital I/O card and programmable relay key matrix ,and used all of this to be the base of software design , then we introduce the block flow of software.