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Aisin World Corp. of America: Automobile Seat Durability Test Stand
Products Used:
LabVIEW 6.1
NI-DAQ 7.0
Measurement & Automation Explorer 3.0
PXI-1002 Chassis with rack mount kit
PXI-6711 Analog output board
TB-2705
PXI-6071E Multifunction I/O module
SCB-100 Shielded Terminal Block
PXI-6508 Digital I/O Module
CB-100
The Challenge:
V I Engineering Inc. has developed a Seat Durability Test System for Aisin World Corp. of America. The tests are performed on up to two seats simultaneously. However, each test can be individually controlled to perform on an individual seat.
The tests procedures involve repeated operation of seat functions along with manual force application to the seat in pre-determined cycles. Seat performance is observed for adherence to specification during test operation. The motor current, motor voltage, travel, load, acceleration, and the number of cycles completed are monitored and recorded. The software also provides utilities for editing of the tests schedules.
The Solution:
Using NI hardware and software for I/O, CLD actuators, Puritan Automation machining, and Circuit Board Services custom interface with Allen Bradley drives allowed this complicated system to come together. The program made by V I Engineering uses LabVIEW to produce an easy to use interface for the engineer in the lab to take control of this large machine.
Abstract:
Aisin's large seat tester requirements push the boundaries of what linear actuators can do. The stand presses a butt form against a seat up to 1500N, accurately following waveforms upwards of 6Hz. The tester applies force to the seat in 4 axis of motion. Three of the motions are governed by independently programmable waveforms capable of functioning in displacement, force, or acceleration modes. At the same time the stand can run a functional test on the power track of the seat. The pattern of seat travel is also programmable. Both varieties of tests keep track of cycle count, collect data, schedule breaks in the test to evaluate the seat, and abort based on operator defined limits.
Overview:
The software is broken up into two tests, a setup for each, and a few manual-testing options.
The Durability - Manual tab (Figure 1) allows the user complete viewing of the entire system. The sections of the display are broken up into force, acceleration, and displacement graphs with a list of channel options to the right. This lets the operator choose the channels they want to view on any graph. The schedule editor allows the user to define which functions are cycled in the Durability - Manual test, how many cycles will occur in the test, how often data should be saved to file and the alarms for the selected schedule. The editor can be accessed via menu on the main screen. In order for the system to be flexible enough to accommodate various seat tests, including future programs, a simple yet through editor was created.
The Durability - Power tab allows the user complete viewing of the entire power track system. The sections of the display are broken up into directional graph pairs. These display current and voltage of motor. The schedule editor allows the user to define which functions are cycled in the Durability - Power test, how many cycles will occur in the test, how often data should be saved to file, the tolerance, and the alarms for this schedule. The editor can be accessed via menu on the main screen.
Cylinder Synchronization
The Analog Output of the system will follow the waveform pattern viewed in the graph. The waveforms are large arrays of single precision numbers corresponding to the amplitude of the output signal. The Update Rate defines the time between each point. Every point of the curve is synchronized on all four channels. The software to ensure signal integrity defines the update rate programmatically. The hardware does have limitations. The software cannot force the hardware to do more then it was designed for. In a case that the user attempts to give the cylinders a waveform outside of spec, a warning will be given that could possibly result in an emergency shutdown of the test.
Alarm Limits
To avoid damage to the seat or the data acquisition equipment, alarm limits are fully configurable for each individual seat being tested. As long as the alarm channel stays within the limits placed upon it and all hardware stays within the hardware limits of the system, the seat will be considered 'good'. If either alarm is breached for any of the four axes, the test will stop. There is also a hardware EStop on the test stand to cut power to the machine for user safety.
Start / Stop Test
The start buttons on both tests allow the user to start and stop the manual durability test. When each test is started, the schedule selected for the seat is run. If a seat schedule isn't loaded, one can be loaded by selecting the schedule once Start Test is pressed.
Pause
At any time the graphs may be paused to allow for the user to zoom in seeing an event in more detail. This only pauses what the user sees. The test still runs continuously. The graphs shall continue to stream incoming data when unpaused. At this time the screens can be printed for documentation and a .jpg file is saved with the data for that test.
Data
During a test, at user definable times, a cycle of data is taken and saved into an excel readable format for convince.
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