Mobile robots: the fundamentals
Safety in layers
Safety is not one sensor. It is layers, each backing up the one before it.
Layer
Means
What it does
Perception
3D vision, lidar
Sees people and obstacles early; slows or routes around
Control
Three-stage response
Slow, soft stop, hard stop
Contact
Safety edges
Touch and it stops
Human
Emergency stop
Anyone can cut power at any moment
Signalling
Light band, voice, buzzer
Tells people nearby what the robot is about to do
Management
Zoning, aisle discipline, training
Reduces conflict by rule rather than reflex
The last layer is the one most often skipped, and it is where incidents come from: stock left in the aisle, unauthorised people in the work area, staff who habitually cut in front of a moving robot.