A Tier 1 Automotive Supplier was seeking to advance its automobile seat test program and reduce its dependence on specialized testing machinery. A general purpose industrial robot with customized tooling would enable multiple test cycles representing passenger loading, unloading and movement in the seat. Each cycle required the acquisition of real-time force data with corresponding updates to the test sequence. The specification stated that both industry-standard ingress/egress and jounce/squirm tests be supported.
The robot controller had to be able to present the large number of test parameters and steady stream of force data in an easy-to-read format. An advanced graphical display was a must. A typical seat test is performed on a prototype, runs for multiple days for hundreds of thousands of cycles and is under time constraints; “rock-solid” software stability was also a must. If a software malfunction occurred during the third shift and no one was present to reboot the machine and resume the test, data could be lost.
The Occubot VI
A KUKA industrial robot was specified because of its highly customizable, user interface running on Microsoft Windows® XP(e) and for its dexterity. A custom application, Occubot VI, was developed to run the tests. KUKA Robots all run KUKA Controls’ VxWin® technology. VxWin extends Wind River VxWorks® Microsoft Windows XP(e); a complete COTS software and hardware solution.
A Microsoft Excel spreadsheet was developed as the interface for the operator to enter test sequences. The sequences are imported directly to the Occubot VI operator interface which then automatically generates the robot path. A standard National Instruments PCI-based data acquisition card is used to collect the force data.How it works
The application monitors force data in real-time as the robot moves along a predefined path over the seat. Dynamic adjustments are made to the robot path to correct the forces as the seat wears.
• File I/O – Path data is written to disk by Excel and read by the test setup application running on Windows XP(e).
• Shared Memory Network – The test setup application communicates path data to the robot control, running on VxWorks, via TCP/IP over an internal shared memory network. Force data is communicated back from the robot controller to the operator interface over the same network.
• Analog I/O – Analog force data is acquired by a COTS National Instrument data acquisition card and sent internally to the robot controller.
Test data is entered into a Microsoft Excel spreadsheet. The data is saved to the disk and read by the Test Setup application. The test setup application automatically generates the path and force data points used by the robot control.
Data Monitoring & Acquisition
A COTS National Instruments data acquisition card is used to read the analog force data sensed by an ATI Industrial Automation force sensor. The force data is read once every 12 milliseconds on each axis. The forces are compared against the desired forces entered during test setup and the robot path is adjusted to correct differences.
Faults & Alarms
Operator faults (i.e., safety curtain incursions and emergency stops) are handled by the robot control software. Faults may be viewed and cleared using the Windows XP(e) operator interface.
Data can be stored to disk for later off-line analysis using tools such as MathWorks® Matlab and Microsoft Excel.
Using the powerful features of Windows XP(e), running on the robot controller, made it possible to quickly create and debug the operator interface. Development time was drastically reduced and due to the familiar interface of Microsoft Excel, operator training time was also reduced. By utilizing the flexibility of the Occubot VI system, the customer was able to successfully replace multiple specialized machines and meet the requirements of new and challenging seat test specifications.