FRI protocol
Work in progress
A detailed description of the FRI protocol is being prepared.
FRI (Fast Robot Interface) is a UDP protocol for low-level real-time control of a KUKA robot. It runs over Ethernet and provides a deterministic data exchange cycle between an external PC and the KUKA controller.
Main characteristics
- Transport: UDP (no delivery guarantee, which is important for real-time operation)
- Cycle period: 5 ms (200 Hz) or 10 ms (100 Hz), configured in
cobot-setting.yaml→robot.fri_cycle_ms - Control modes: position, torque, and impedance
Network requirements
Important: a 5 ms cycle requires KONI
A 5 ms (200 Hz) cycle requires the KONI port (KUKA Optional Network Interface).
The KLI port supports only a 10 ms cycle. Set fri_cycle_ms: 10 when using KLI.
| Port | Minimum cycle | Purpose |
|---|---|---|
| KONI | 5 ms | High-frequency control, recommended for FRI |
| KLI | 10 ms | Standard control and programming |