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Cutting The Cable

Integrated electronics turn regular dummies into iDummies

iDummy is a crash test dummy with integrated on-board data acquisition, making it the first design to eliminate the need for an external umbilical cable to feed data from the embedded sensors to a remote data acquisition system. In addition to being smart, iDummy is svelte. According to Jim Flachsmann, manager, iCrash Tech-nology, First Technology Safety Systems (FTSS; Plymouth, MI; www.icrashtech.com), "a standard system requires about 17 lb. of umbilical cable for every 64 data channels, in addition to the weight of the data acquisition unit and batteries." In all, about 80 lb. are saved by using iDummy-mass that would have to be removed from the test vehicle before a crash is conducted.

Removing the cabling also can save time and improve data quality. Before a crash test can be run technicians must place the conventional dummies in position-no easy task considering the size and inflexibility of the umbilical cable-and each channel must be tested to see that it is working. This is calibration that must be done in the vehicle or on the sled. "Honda is an iDummy customer," says Flachsmann, "and it reports savings of about three man-hours per test because all of the calibration and set-up work can be done off-line. And, since the data acquisition systems aren't dedicated, they can be moved from one dummy to another, so you don't have to purchase as many units." In addition, the absence of external cabling means the kinematics of the dummy in a crash are more like those of a human being, and easier to replicate.

There's only one problem with the whole iDummy scenario: It can't be used to run an official government recognized crash test. "NHTSA requires that you meet their drawing package for the dummy in order for your certification crash test to be considered in compliance," says Flachsmann. "We have data to show that the iDummy design doesn't alter the performance of the test-and, to be fair, NHTSA has been very receptive to our research-but the official tests must still be run using a conventional dummy until the regulations are changed." This change isn't expected anytime soon as it requires that the agency assign a team to upgrading the drawing packages for all existing certified dummy designs at a time when it is gathering data that will be used to revise those designs at some point in the future. "That's one reason we followed the path we did," says Flachsmann.

Instead of limiting itself to these new designs, FTSS upgraded its current inventory to accept integrated data acquisition systems. This meant creating room for as many as five TDAS G5 32-channel data acquisition units from Diversified Technical Systems (Seal Beach, CA, www.dtsweb.com), each of which can be connected through an internal distribution hub. "A single cable exits the iDummy, and on-board batteries allow it to run either completely cable-free or provide back-up power," says Flachsmann. "Small channels are added in the skin and spine box to carry the cabling for each transducer. It can be disconnected at the sensor for maintenance and calibration without having to pull the inner cables."

An iDummy isn't cheap-a complete system runs about $150,000 per unit-but the cost is in line with that of current technology and it lets you do more tests with less overall equipment. "It's a bit like crashing a Wall Street banker into a wall, but the upside is that you can do it over and over with little downtime," jokes Flachsmann.