High-impact automotive testing

Extreme collisions can cause vehicle systems to fail, putting passengers at risk, so regulators in the United States and other countries increased standards for individual components. Recently, a Japanese automaker needed to show that its seats could stand up to rear collisions from trains, a rare but typically fatal situation.

To verify that its seats could stand up to that strain, the manufacturer turned to Moog Inc., a diversified manufacturer known for taking on engineering challenges, especially for designing test rigs.

“The manufacturer intends to confirm the relationship of horizontal, backward load applied by the passenger in the seat, at the time of a rail collision,” says J. Thilak Kumar, Moog India’s program manager for the National Automotive Testing and R&D Infrastructure Project (NATRiP). “It needs to show the integrity and strength of the seating system.”

As is often the case, the manufacturer simulated the seating system digitally and applied several extreme, real-world collisions – including rear-end impact from a train. While the seats passed those tests, the simulation still needed physical, real-world confirmation from Moog’s test rig.

“Simulation gives you a ballpark number to work with,” Kumar says. “You can see all of your design components. But physical testing gives you hard data to confirm the simulations.”

Kumar’s team designed an electro-mechanical test system based on Moog’s Electric Linear Actuation Solution. It uses three electric actuators, each capable of 500kg of downward pressure; a portable test controller with three channels; three servo drives; and test software. The servo motors move the actuators in a vertical direction to compensate for vertical displacement of the seats. An angle sensor placed on the seat provides information concerning seat displacement to determine the correct actuator height.

During the early stages of development, Kumar says his team tried using hydraulic drive systems, but they quickly opted for electric actuation for speed and precision.

“We walked away from hydraulics because the system had gotten bulky and because of the power requirements and speed constraints,” Kumar explains. “The electric systems give you a very clean environment, and it gives you much more speed.”

While designed for the extreme case of car-train collisions, the system can physically simulate and test situations from front-end fender benders to side collisions. Officials at Moog are considering marketing the setup to manufacturers of doors, switches, pedals, and any other component that might fail in extreme conditions.

“Physical testing is still a vital requirement for manufacturers to prove their safety systems,” Kumar says. “These systems will help confirm that these components are safe.”

Moog Inc.
www.moog.com

About the author: Robert Schoenberger is the editor of TMV and can be reached at 216.393.0271 or rschoenberger@gie.net.