Our team recently talked to a robotics scientist about new cars using sensors. We asked him a few questions:
Q. What sensors do the use?
A. They use Radar for forward collision and vision for lane departure.
Q. Do they use ultrasonic sensors specifically?
A. Ultrasonic sensors are used for backup incase the Radar fails.
Q. What is the hardest problem in designing them?
A. Each sensor has different problems, Radar has problems when determining wether an object is in-path or out-of-path (you don't want to warn the driver that he's passing by mailbox on the road side). Vision has problems locating poorly marked lane stripes.
Q. What weather conditions can cause problems? (For example, it could think that you are about to crash into a group of snowflakes, so it would stop.)
A. Radar works pretty well in bad weather. Vision systems have problems with direct sunlight, oncoming headlights, reflective road surfaces, and other things of that nature.
Q. What is the range for ultrasonic sensors?
A. He is not exactly sure, he would guess ultrasonic sensors for backup would typically be 0-3m.
Q. What are the limitations for ultrasonic sensors?
A. One limitation is that an object can appear invisible if it's surface angle with respect to the sensor direction gets large. The acceptance angle of the detector is called it's field of view (FOV). If the object's surface exceeds half the FOV then there may not be enough energy captured.
For more information on sensors click HERE.
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