!
Figure 15: Without the particle filter: Violation
of the contour due to dust particles in the
vicinity of the object.
"
Figure 16: Using the particle filter: The
response to dust particles in the field is
delayed by one scan. Particles can thereby be
blanked.
3.6.8
Calculation of the field size for mobile applications
In order to prevent collisions between vehicles, and between vehicles and fixed objects,
the switching field must have sufficient length and width.
To calculate the switching field length, you need to take into consideration the stop‐
ping distance of the vehicle. This comprises the following:
•
the braking distance, which can be found in the vehicle documentation
•
the distance covered during the vehicle control’s response time, which can be
found in the vehicle documentation
•
The distance covered during the response time of the LiDAR sensor,
NOTE
•
We recommend adding a supplement of at least 100 mm to the protective field
length in order to stop the vehicle before a possible collision.
•
If retro-reflectors are situated in the path of the vehicles, or if you anticipate that
the braking force of the vehicle will diminish over time, you may, under certain
circumstances, need to increase the recommended supplement.
•
The width of the switching field should cover the vehicle width. You should also
configure a supplement of at least 100 mm on every side.
Height of the scan plane
The recommended mounting height for mobile applications is at least 150 mm.
3.6.8.1
Switching field length
You must configure the switching field so that a minimum distance to the vehicle is
maintained at all times. This ensures that a vehicle monitored by the LiDAR sensor
stops before an object is reached. You can define multiple monitoring cases each with
different switching fields. These can be switched over dynamically via static control
inputs, for example to adjust the switching field size based on the vehicle speed.
In this kind of application, you must calculate the switching field sizes (in particular the
switching field lengths) for all speeds.
The switching field length SL can be calculated using the following formula (guideline
values based on a pixel calculation):
SL = SA + ZG + ZR + ZB
SA
= Stopping distance
ZG
= General safety supplement for the LiDAR sensor = 100 mm
3
PRODUCT DESCRIPTION
22
O P E R A T I N G I N S T R U C T I O N S | TiM3xx
8024851//2021-07-21 | SICK
Subject to change without notice
