Category: Aerospace

Improving Pilot Display Unit (PDU) testing

12/4/2018

Amfax delivers a new generic ATE for testing aerospace pilot display unit modules. The system enables testing of all module types using the same tester

Amfax have recently designed, built and delivered core PXI based automated test systems to a major aerospace manufacturer. The brief was to come up with a design that could test all the pilots display unit (PDU) modules using a single automated tester. Previously the client had a number of ATE's that each tested just one module. This meant that previously the client not only had to invest in multiple testers but had to obtain support for each unit separately. The ATE used a fully loaded PXI rack to house all of the instrumentation needed to ensure test coverage of all the measurements required for each module. The modules tested included a solar cell, electronic display, interface unit and auxiliary PCBs.

System benefits:

The test system was easy to use by the operators. This was achieved by careful design of the GUI
The client could take up ownership easily to due the modular nature of the system
The self test fixture enables easy and regular maintenance of the system
Modular design enables easy repeat system build

System features:

PXI based instrumentation
Wire free multi-interconnects using MAC Panel Scout interface
Safety interlocks on cabinet to comply with stringent health and safety requirements
Fully CE Certified
Supplied by AS-9100 aerospace approved supplier

CASE STUDY - Eurofighter (Typhoon) hydraulic test rig

8/2/2016

The purpose of hydraulic test rig project was to provide a software solution to control a hydraulic test bench and execute sequences to test the performance and functionality of hydraulic components from the Eurofighter aircraft. Amfax was asked to work in conjunction with a hydraulic equipment manufacturer to design and develop both the software and the hardware.

Key benefits of Amfax's involvement

Assistance in the specification and design of system hardware
Delivery of a distributed real time control system using the latest innovations from National Instruments
Accommodate and design custom pump control loops using a PID implementation
Design allowed for switchable / isolatable hydraulic power supplies
Engineers worked through design, development and test witnessed and accepted by the Eurofighter Nation's Airforces

The resulting system was a generic test platform which allowed the end customers to strip and test Eurofighter hydraulic components without having to send them back to the manufacturer.
This vastly reduced the costs for supporting operational aircraft.

System safety and design innovation were key

Operator safety was a key consideration for the hydraulic test rig. Hydraulic power packs capable of delivering 360bar pressure or 180 l/m flow could do serious damage. Our solution's design addressed these concerns

Real time control

The safety critical system was built around an NI-PXI RT controller and LabView RT.

A time critical 50ms epoch for the control system which was able to guarantee timely reaction to a change, such as a pressure surge in a fixed time frame

C.B.I.T

The CBIT or (C)ontinuous (B)uilt (I)n (T)est was designed to monitor active system pressures, flows, voltages and currents.

Any deviation from normal caused the system to cut all power from supplies, either hydraulic or electric.

Watchdog

In addition to the C.B.I.T., a watchdog relay governed all electrical controls for the system. If there was ever a critical failure on the RT controller, this watchdog relay ensured any active power to the control system would always be cut.

System software and hardware used

LabVIEW
LabVIEW was used as the primary development language for this project and delivered the following benefits :

Rapid development
Hardware support
Accredited code standards
Wide industry support

LabVIEW Real Time
The real time module for LabVIEW allowed us to make use of PXI RT hardware, broadening the scope and capability of this system.

Deterministic Epoch
Safety critical

TestStand
Each type of hydraulic component needed its own test sequence with step by step limits and custom control conditions. TestStand was the natural choice for this and offered these benefits :

Separate test from application
Custom step types
Separate installers

Hardware
The RT system hardware was housed in rackmounted PXI chassis, one chassis in each hydraulic power supply and one in the hydraulic test bench, in some of the installations, these components were housed in separate rooms.

The user interface was housed in a control and display unit, controlled by a 19" Rackmount Industrial controller running a Windows operating system.

Test Bench hardware included

Digital I/0
Analogue I/O
DMM
Counter timer module
Scope
Arb

Hydraulic power supply control included

Digital I/O
Analogue I/O
Counter timer module

Control and display unit contained

Industrial controller
Dual monitor output
Printer for automatic reports

Examples of recent project work undertaken

Improving Pilot Display Unit (PDU) testing

CASE STUDY - Eurofighter (Typhoon) hydraulic test rig

Key benefits of Amfax's involvement

System safety and design innovation were key

Real time control

C.B.I.T

Watchdog

System software and hardware used

Our recent work

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