A Magnetohydrodynamic Angular Motion Sensor for Anthropomorphic Test Device Instrumentation

Applied Technology Associates, Inc., (ATA) has developed a new angular motion sensor based on the laws of magnetohydrodynamics for the Department of Transportation. The magnetohydrodynamic angular motion sensor (MHD AMS) was originally developed for the Air Force for measurement of ultralow angular motion on pointing and tracking platforms. The transducer developed for the Department of Transportation, MHD AMS model IETL-001, or simply IETL, is a smaller, lighter version of the original MHD sensor with modifications which allow measurement of the high angular velocities incurred by the Anthropomorphic Test Device (ATD) heads in crash testing. The IETL weighs approximately 35 grams (1.2 02.) and occupies a volume of about 5 cubic centimeters (0.3 cubic inch). ATD application test results verify that the IETL exhibits both low cross-axis angular sensitivity and low linear acceleration sensitivity. These are important features for angular motion measurement in high shock environments, i.e., crash testing.

The principle of operation, the physical and performance characteristics, and the ATD head application test results will be presented. In addition, a brief discussion of other related applications and design improvements will be given.