Developing smart vehicles requires a tradeoff: As the vehicle gets more intelligent, it also gets more complex. You can look no further than the number and kinds of sensors newer vehicles now come equipped with to appreciate just how complex. These vehicles that once started as little more than an engine, four wheels, and some brakes have become highly sophisticated computers on wheels.
To improve safety, the typical piece of heavy equipment might be equipped with RADAR, LiDAR, and ultrasonic sensors, in addition to mirrors, cameras, flashing lights, and backup alarms. These devices work together to create an environment that is safer for vehicle operators and everyone and everything around them. We have previously discussed the difference between RADAR and LiDAR. In this post, we’ll take a look at ultrasonic sensors and why they are used as part of a vehicle safety package.
RADAR uses high-speed radio waves to accurately detect stationary or moving objects up to about 500 feet away. For this reason, these sensors can be used to detect fast-moving objects and are used for such advanced driver-assistance system (ADAS) tasks as adaptive cruise control, automated highway driving, emergency braking, collision avoidance, lane-departure warning, blind-spot detection, and lane centering.
Similar to radar, ultrasound works by emitting waves, but in this case, they are high-pitched sound waves. They are used in everything from proximity alarms, medical ultrasounds, and for generic distance measurement. They can help analyze the purity of liquids, break up kidney stones, and help fisherman find fish. To work well, the object the sensor is trying to detect must be made of materials such as plastic, steel, or glass that easily reflect ultrasonic waves. If the object is made of something that absorbs the waves, such as fabric, the sensor must move closer to the object.
When used for object detection in vehicles, they work like RADAR, evaluating their targets by measuring the time it takes for a wave to be reflected off an object and back to the sensor. Unlike RADAR, ultrasonic sensors can only detect objects that are up to about 30 feet away. As such, they are used for relatively short-range tasks, such as the detection of nearby objects when a vehicle is being parked. Vehicle manufactures are now using ultrasonic sensors as part of the automatic parking systems being installed on high-end commuter cars. These systems automatically control steering, acceleration, and braking, based on the parking zone and location information gained from the
As ultrasonic technology advances, so do the possible uses of these sensors. Tesla currently places 12 ultrasonic sensors on its S and X models to provide drivers with close-range obstacle detection as part of their “AutoPilot” feature. And in the future, ultrasonic sensors may be used to provide autonomous vehicles with a 360-degree view of obstacles in the near vicinity in addition to LiDAR and RADAR.
Consumer vehicle manufactures like ultrasonic sensors because they are compact and reliable; consume very little energy, and are very good at measuring distances to parallel surfaces, such as the walls in parking garages. Unlike RADAR sensors though, they can be affected by the vibrations of heavy equipment and the inherently dirty and dusty environments these machines run in.
The point of this post is not to say that one of these object-detection technologies is better than the other. If your equipment typically operates in harsh environments such as construction sites or mines, RADAR would make more sense. Adding RADAR as a lane change assist, urban VRU (vulnerable road user) warning or rear blind spot monitoring system in addition to an ultrasonic system for on-road fleets only adds another level of safety for both operators, other drivers, and vulnerable road users.