Company: TBG Solutions
Author(s): Jonathan Hobson
NI Product(s) Used: LabVIEW
Industry: Test & Automation, Control
The Challenge
The customer approached TBG with the requirement to convert a manually controlled actuator test system into a software controlled automated test system. The software needed to allow the operator to control all aspects of a Parker Compax3 drive and MH series motor capable of speeds of up to 10,000 rpm.
The Solution
The solution by TBG Solutions is a bespoke LabVIEW application that allows for full control of the motor drive as well as a profiling application to allow for automation and sequencing of ramp rates and dwell times to fulfil the critical test specification of the UUT.
TBG created our own driver set for communication with the motor drive, of which is the first of its kind for the Compax3 series of motor drives, the ease of the Object-Oriented method of programming and the capabilities of LabVIEW’s acceptance of a HAL environment means that the software is scalable to multiple test sets and can be transferred over to other motors and drives
TBG Solutions
Introduction
The customer is one of the world’s leading aerospace component manufacturers, specialising in actuator and motor systems for a range of aircraft they required a software-based solution to upgrade an existing manually controlled friction brake actuator test rig to be fully automated with an intuitive interface.
Initially the customer was told by other integrators that this would not be possible, however the experience of TBG Solutions and our capabilities gave us the confidence that this could be done and not only could we produce the software in house but also make use of our in house mechanical and electrical expertise to make changes to the inner workings of the test rig to allow for full control in software.
We were able to make use of the LabVIEW IDE and its prebuilt functions for serial RS232 communications to build a OOP based HAL for the Parker Compax3 Motor Drive, this provides flexibility and scalability for communication between multiple systems and different motors.
Application Description
As mentioned, the application makes use of the OOP programming architecture this coupled with TBGs own OOP based QMH design pattern allows for a scalable application architecture where events and error handling are organised and reliable.
Example OOP HierarchyThe key area of the project was to ensure that we could achieve stable and reliable communications with the 3rd party device. Due to there being no manufacturer provided driver TBG had to revert to using our experience in driver production as well as the comprehensive serial communication user manual for the motor drive. This enabled us to create a HAL based driver set for the motor drive that handles all initialisation, read/write, error handling and shutdown controls for the motor drive.
System Setup - The system is ultimately controlled by a LabVIEW based driver set sending and receiving commands to a Parker Compax3 motor drive and motor. Feedback from this motor is also displayed on COTS indicators showing the speed and torque on the shaft and UUT. The system itself connects via RS232 to a laptop within a rugged Pelican case designed and manufactured in house by TBG solutions to the highest standards. A basic system overview can be seen below.
System Diagram
The Software Interface of the application can be split into 4 discrete parts which are:
Main Interface – This the main launcher where a user can select different screens dependent on their requirement such as the profile editor, manual control or even user management. All buttons are enabled/disabled based upon the user’s credentials (i.e. admin, engineer or operator).
Main MenuProfiler – This is where the user can create or edit a test profile for UUT testing. They have full control over adding and removing steps, when adding steps, they can ramp up, ramp down, dwell or stop, the add step popup will dynamically change the available step options based upon the step chosen, these options include direction, acceleration and speed.
Profile Editor ToolsRun Profile/Test – This is where a profile can be loaded and run and in turn commands sent to the motor drive to test. The interface is minimal, the user can see the loaded steps of the profile and can set the system to run multiple cycles of the same test whilst viewing critical data such as motor temperature and voltage via an asynchronously loaded status monitor.
Test ScreenManual Control – As well as automating the test procedure, the user may require to manually control the motor to debug a potential issue with the UUT or run the UUT to a high speed with maximum control. This is done via a dedicated manual control screen which utilises the same HAL based commands to the motor drive. The screen is constantly monitoring interlock and e-stop conditions to ensure that operation can’t take place whilst a guard door is open or the system is in a n E-Stop situation. The user can gain full control of direction, ramp rate and speed with this screen whilst again making use of viewing critical data in the status monitor.
Manual Control Screen
Platform Based Approach Benefits - By implementing a platform based approach, Integration of NI hardware with 3rd party motors and drives was simplified using the LabVIEW environment. By having prebuilt libraries for handling serial communications meant half of the work was done in terms of TBG's custom library, this lead to reduced development time and delivery ahead of schedule compared to if we had used other software IDEs.
The use of the LabVIEW OOP capabilities means that we can create an application that not only exceeds customer expectations but also allows for a fully scalable design architecture which serves as a base foundation for further systems and other projects.
Impact/Results
Since delivery, the system has tested thousands of units where previously they would have tested hundreds manually. The system runs daily with the customer reporting good feedback on the usability and reliability of the system, keeping them on track in terms of units tested and at the forefront of the aerospace industry.
Conclusion
Overall, the combination of prebuilt libraries, the capabilities of LabVIEW and the scalability of the OOP environment, TBG were provided with a base IDE that allowed for ease of integration with 3rd party devices and provide the customer with an intuitive, efficient and reliable interface whilst hitting all function specification and test requirements.
