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This work is based on a current project funded by the United States Army Small Business Innovation Research (SBIR) Program and is being conducted with the Tank Automotive Research, Development and Engineering Center (TARDEC) Ground Systems Survivability (GSS) Team and Paradigm Research and Engineering. The focus of this project is to develop an advanced and novel sensing and activation strategy for Pyrotechnic Restraint Systems, Air Bags and other systems that may require activation. The overriding technical challenge is to activate these systems to effectively protect the Soldier during blast events in addition to Crash, Rollover and Other Injury Causing events. These activations of Pyrotechnic systems must occur in fractions of milliseconds as compared to typical automotive crashes.

The Magnetostrictive Dynamic Strain Sensor is a permanent-magnet constant-flux excitation sensor and thus requires no other electrical excitation or power source. It does not require any signal conditioning. Since it is a constant-flux dynamic sensor, it does not generate any offset voltage and it does not exhibit temperature or drift problems. Furthermore, the sensor is rugged, simple and inexpensive. The sensor's time-averaged output is constantly zero. The sensor detects only dynamic events such as impact, crash, firing (or misfiring) of an engine cylinder, piston slap, vibrations of a machine component, vehicles passing through a bridge, etc. Therefore, the sensor has many promising automotive applications including crash and misfire detection.

Magnetostrictive sensors offer many attractive features. Their strain sensitivity is significantly higher than that of strain gages. They are simple, rugged and inexpensive. Signal conditioning requirements for the magnetostrictive sensors are determined by the selection of a signal detection method. This article experimentally investigates different signal detection methods for single branch magnetostrictive sensors with conventional excitation and detection coils. Monitoring excitation voltage while holding excitation current constant, or monitoring excitation current while holding excitation voltage constant produces much better output signal compared to the detection voltage. Furthermore, this study suggest that the detection coil is not really needed, leading to a novel single branch magnetostrictive sensor without a detection coil.