SAFE SOFTWARE, LEGALLY LIABLE
All of these sensors and redundant processing bring
up the issue of software. The analysis and complexity
challenges are large, but they will be trivial compared to
the standardization and legal hurdles associated with
active safety.
A few standards are popular but not universally
adopted, such as AUTOSAR (AUTomotive Open System
ARchitecture). Likewise, protocols for networks like CAN
are standardized, at least at a low level, though vendor
exceptions abound.
Wireless sensors like Freescale’s MPX8300 are
embedded in a tire with the receiver in the body of
a car (see “Tires Put Pressure On RF” at www.electronicdesign.com, ED Online 16497). Unfortunately,
dissimilar radios and protocols can make it difficult to
go to the nearby auto parts store for a replacement.
The plethora of wiper blades and headlights is just a
fraction of what will occur with the inevitable increase
in sensors and associated processing systems.
In the longer term, cooperation between the vehicle
and other cars or fixed wireless information sources will
provide details that can be incorporated into the safety
system. This is already done, albeit on a limited basis,
with some GPS navigation systems that receive traffic
information via radio.
One alternative that’s been tossed around would have
cars talking to cars and sharing their environmental sensor
data with each other. This would reduce the reporting
requirements and related delays of the radio-based GPS
navigation systems in place while significantly increasing
the accuracy and timeliness of the data.
Unfortunately, this approach opens a can of legal
and standardization worms. How do you prevent invalid
information from being inserted from a third party? What
happens if an accident arises due to the exchange of
bad or insufficient data? What cars will talk to each
other? The list goes on.
Other interesting ideas hovering on the radar include
heads-up displays (HUDs) and verbal interaction. The
cost and effectiveness of these technologies aren’t
right for mass markets yet, but the same once was true
for vision systems, automatic stability control, and a
host of other features, including airbags. A HUD allows
overlays from the vision systems, enabling direct driver
feedback—and that’s only one possible use. Overlaying
building and terrain information is another.
Voice-activated command systems are already
common for multimedia device and climate control.
Advances in voice recognition and the ability to bring
more computing power to bear will allow this interface
methodology to improve. In turn, it will reduce the need
for drivers to interact with the car via manual controls,
thereby improving overall automotive safety.
ELECTRIC SAFETY
Hybrid and electric vehicles are becoming more prevalent,
but they add their own safety issues to the equation.
The primary concerns deal with high voltage and
the batteries required by the system.
Most systems employ a multicell battery pack. For
example, Tesla Motors’ Roadster has a battery pack
that incorporates more than 6000 lithium-ion (Li-ion)
cells in the 18650 form factor, weighing almost 900
pounds (Fig. 7).
The system uses multiple microprocessors and sensors
to monitor each cell as well as the battery cooling
system’s temperature. Additional sensors track the
environment and initiate a shutdown when an accident
occurs or when maintenance is required.
Popular hybrids such as the Honda Civic and the
Toyota Prius have less ambitious power systems, but
their battery sensor and control systems are no less
important (Fig. 8). Improvements in sensor technology
and price reductions in microcontrollers will allow even
safer systems to be constructed, including the cabling
and connection points.
It should be interesting to see what kinds of safety
systems next year’s car models have in store.