hardware-watchdog

What problem does it solve?

If the ROS 2 host or controller firmware dies or communicates fail, the robot can continue driving with stale commands, risking collisions. This Skill defines a multi-layer watchdog strategy to guarantee safe motor states by combining MCU software watchdogs, hardware watchdog timers, ROS 2 watchdog nodes, and a robust safety chain.

Core Features & Use Cases

• Layer 1: MCU Software Watchdog using IntervalTimer to detect missed host packets and trigger safe motor stops.
• Layer 2: Hardware Watchdog Timer (WDT) to reset the MCU if the firmware hangs beyond the configured timeout.
• Layer 3: ROS 2 Watchdog Node to monitor /cmd_vel flow and publish zero velocity on timeout, with status flags.
• Layer 4: Velocity Multiplexer Priority to ensure safety commands override navigation when a fault is detected.
• Layer 5: Physical Emergency Stop to cut power to motor drivers, independent of software.
• Heartbeat Protocol and complete safety chain to coordinate failures across layers.
• Testing guidelines to verify behavior under node failure, USB unplug, MCU hang, and e-stop.

Quick Start

Enable and validate the multi-layer watchdog system across MCU software watchdog, hardware watchdog, ROS 2 watchdog, and safety stop sequences.