Car seat solution saves a few butts

ControlDesign.com

Keywords: automotive industry, testingfactory automation systems, industrial automation, process automation and control systems

Data handling capability and after-sales support got a boost when this test equipment builder switched to PC-based control. By Managing Editor Steve Kuehn.

 By Steve Kuehn, Managing Editor

afety system developers, especially those that supply the automotive industry, continually evaluate available new technologies in hopes of staying ahead of the evolving safety regulations curve. Sterner Automation, a Toronto-based engineering firm that specializes in custom testing machinery and end-of-line test calibration equipment, is one company that is fully aware its safety testing equipment can save lives. Because its products play such a critical role, Sterner believes that simply meeting its customer’s expectations is just not good enough. The company also believes that a switch to the right control platform—at the right time—can make a good solution better.

Sterner recently went hunting for an alternative to the PLCs and motion-controllers it uses to automate a machine that calibrates and tests in-vehicle safety sensors for automotive industry applications.

What it found was a PC-based solution that met its expectations in both machine performance and enhanced customer support capability.

Test Time
The Sterner machine’s test process begins by conveying a car seat (traveling on a pallet) into a testing station. A scanner reads its barcode for identification and a factory information system (FIS) uses that information to determine the right “recipe” for the proper testing and calibration for each type of seat.

After the seat and its pallet are lifted and locked into position, the test and calibration operator passes through a system-disabling light curtain to connect a harness to the seat. The operator then steps back through the light curtain, returns to his station and resumes the procedure. During the calibration test, the control system communicates to the seat’s electronic control unit (ECU) using a vehicle communication protocol interface unit manufactured by Sterner.

The sensors the machine tests and calibrates determine the weight of, and the acceleration force on the vehicle’s passengers and drivers.

The "butt” form—the element of the Sterner machine that's lowered onto the seat—applies varying degrees of weight. This tests the sensors to make sure the safety system will differentiate between the weight of an adult and that of a child. This is important because the force of an inflating airbag can injure a child if it is designed solely to have enough force to prevent an adult from striking the dashboard.

When the calibration process is complete, all tooling and test equipment is retracted, the operator disconnects the test harness and steps clear of the light curtain, and the conveyor is signaled to move the seat out of the testing station.

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						The "butt form" applies varying degrees of weight to the seat. This tests the sensors to make sure the safety system can differentiate between an adult and a child by weight.

We Can Do Better
Sterner’s engineers realized they needed a refined control solution that would allow remote monitoring of machine performance, while reducing the training and maintenance costs incurred by its customers. Sterner also sought to decrease assembly time and simplify the hard wiring and connections required in the machines.

"At the time, we were applying a typical PLC architecture along with either an industrial PC running an operator interface package or a simple touchscreen display,” says Victor Hilario, manager of the Electrical and Control Systems Group at Sterner. “We were determined to take the next technology steps and design a system that would ultimately be more flexible and allow for a more seamless design evolution. We felt a PC-based system would allow us to enhance the remote diagnostic and troubleshooting capabilities of the product, while staying within industry-accepted standards for programming.”

The PLC-based system also had relatively limited memory for historical equipment data. Sterner wanted to design a system that would provide its engineers and technicians with months of test data including detailed machine diagnostics information. This information is extremely valuable because Sterner can use it to provide customers with superior preventive maintenance and service support by improving the ability to troubleshoot faults based on past events, as well as conduct more thorough fault and failure analyses with better operational data.

Sterner considered the possibility of developing its own proprietary PC-based solution. “Ultimately, we realized we didn't want to offer an overly proprietary solution that would limit our ability to program effectively,” says Hilario.