New Siemens Sensor Technology Gives Airbags Depth Perception
17 October 2000
New Siemens Sensor Technology Gives Airbags Depth Perception DETROIT, Oct. 17 In the spirit of Convergence 2000's theme
of delivering technology's promise, Siemens Automotive today has announced its
three-dimensional object/occupant recognition sensor will make its production
debut on a 2003 model-year European and U.S. small car application, augmenting
the airbag safety system.
Originally developed in cooperation with Siemens Corporate Technology
researchers and the Fraunhofer Society for Microelectronic Circuits and
Systems in Duisburg, Germany it is the first three-dimensional object/occupant
recognition sensor based entirely on semiconductor components.
The new method, called multiple double short time integration (MDSI),
directs near-infrared, low-power laser pulses through the passenger
compartment of the vehicle.
A Complementary Metal Oxide Semiconductor (CMOS) image converter with
extremely short integration time detects the reflected light, which is then
processed by an image converter chip. In only one thousandth of a second, the
distances of 1000 different object points are simultaneously measured to an
accuracy of one centimeter, creating a three-dimensional image of objects
within the passenger compartment.
"The new semiconductor-based design is extremely robust and can be mass
produced, taking advantage of economies of scale," said Bruce Wrenbeck,
Siemens Automotive Director of Safety Electronics Restraint Systems. "Its
efficiency and cost effectiveness allows the three-dimensional occupant
recognition sensor to lend itself to many different applications."
Previously, occupant sensing has been accomplished by utilizing a laser
pulse deflected by a mirror, a highly technical method that is not as robust
or timely as required by the automotive industry.
In order for three-dimensional occupant sensing to be applicable to the
automotive industry, the issues of unit size, processing speed and computer
memory needed to be addressed.
"First, the technology must be transparent to the end customer," said
Wrenbeck. "The CMOS enables us to miniaturize the sensing electronics, plus
it allows us to use a laser that has a low power requirement."
"Processing speed and memory are extremely critical. The time it takes
for the system to continuously reacquire occupant data must be as close to
real time as possible," said Wrenbeck. "Always knowing the position of the
occupant will enable the system to more intelligently deploy airbags during
collisions."
Wrenbeck states that Siemens Automotive is looking to use the occupant
sensor to augment the control and safety of airbag triggering on passenger
vehicles.
"Mat or weight sensors in the seat gives us the occupant classification,
but 3-D sensing enhances this data with a position measurement," said
Wrenbeck. "And as position measurements gain increased mapping capability and
resolution, occupant safety systems will become more and more intelligent."
