LiDAR (Light Detection And Ranging) is a ranging sensor that measures distances by emitting laser pulses and timing their return after reflecting off surrounding objects. Mounted on a mobile robot, it produces a 3D point cloud used by SLAM to map the site and detect obstacles.
LiDAR: how it works and concrete examples
A 2D LiDAR scans a single plane (often at leg or wheel height), sufficient for detecting an obstacle on the ground and triggering a safety stop. A 3D LiDAR scans several planes at once and produces a volumetric point cloud, which makes it possible to recognize more complex shapes, a pallet, a rack, a moving person, and improves the robot's overall perception.
Material-handling robots generally combine several LiDAR units and cameras for 360° perception. The robot carries a 3D LiDAR paired with depth cameras to detect people, equipment and obstacles in real time, with dynamic avoidance and route recalculation. The MiR1200 Pallet Jack goes further by combining three 360° SICK laser scanners, five 3D cameras and a top-mounted 3D LiDAR. The STILL AXL 15 iGo combines LiDAR and 3D visual SLAM to load trucks with no floor infrastructure.
On a robot, LiDAR therefore serves a dual function: feeding navigation (via SLAM) and ensuring safety (obstacle detection and avoidance), often using the same sensors.
LiDAR differs from a simple camera in that it measures distance directly, independent of lighting conditions: it works just as well in full light as in a poorly lit area of a warehouse. That's why manufacturers most often combine LiDAR and cameras (sometimes depth cameras) rather than choosing one or the other: LiDAR secures the distance measurement, while cameras enrich shape recognition (standard or non-standard pallets, people, moving obstacles).
The autonomous pallet truck carries a 3D LiDAR paired with depth cameras for 360° perception. See the product page.
FAQ
What is the difference between a 2D LiDAR and a 3D LiDAR?
A 2D LiDAR scans a single horizontal plane, sufficient for detecting obstacles at ground level. A 3D LiDAR scans several planes and produces a volumetric point cloud, which improves detection of overhanging obstacles or complex shapes such as pallets.
Is LiDAR used only for navigation?
No, it also serves a safety function: detecting people, vehicles or static obstacles to trigger a slow-down, a detour or an emergency stop. Navigation and safety often rely on the same LiDAR sensors, which limits the number of components to install on the robot.