The principle of ultrasonic sensor is simple, convenient and low cost. But the current ultrasonic sensors have some drawbacks, such as reflection problems, noise, cross issues.
If the object being probed is always at the right angle, the ultrasonic sensor will get the right angle. Unfortunately, in practice, it is very rare to detect objects correctly.
Several errors may occur:
When the measured object and the sensor are in a certain angle, the distance and actual distance detected have a triangular error.
The problem is the same as the light reflected in high school physics. At a given angle, the sound waves are reflected by a smooth object mirror, so that the echoes cannot be produced and the distance readings cannot be produced. The ultrasonic sensor ignores the existence of the object.
This phenomenon is more common in detecting corners or similar structures. Sound waves are received by the sensor after a number of bounces, so the actual detection value is not the true distance value.
These problems can be solved by using multiple ultrasonic loops arranged in a certain angle. By detecting the return value of multiple ultrasonic waves, the correct readings are screened.