The rapid urbanization of the world has led to an increase in pedestrian involvement in automotive crashes,
prompting some countries to establish pedestrian regulations. A promising approach to address pedestrian safety is the
use of active lift devices to raise the hood upon detection of a pedestrian impact, thereby increasing the crush distance
between the hood and vehicle hard points (i.e. engine). Current systems are generally not reusable or resettable and lack
extrinsic effect compensation. The dual chamber SMArt (SMA ReseTtable) lift system presented in this paper is a fully
automatically resettable system utilizing a stored energy approach with a pneumatic cylinder and a two stage ultrafast
shape memory alloy (SMA) actuated valve. This active lift possesses the unique functionality to tailor lift performance
and compensate for extrinsic effects such as changes in temperature, mass, and platform using cylinder pressure and
exhaust valve opening timing profile as operating parameters. As a proof of concept, a dual chamber SMArt lift system
was designed, fabricated, and installed in a vehicle hood bay testbed. Full cycle tests demonstrated the functions of lift,
lower and reset within the proper timing. The effect of additional mass, was experimentally characterized and two insitu
device parameters, pressure and valve profile, were investigated as means to mitigate these extrinsic effects. This
experimental study indicates that the dual chamber SMArt lift device may be a feasible alternative for pedestrian
protection with automatic reset/reusability along with capability to adapt in-situ to maintain performance within a narrow
timing window by compensating for extrinsic effects.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.