emergency-stop

A multi-layer emergency stop integrates a physical NC pushbutton, MCU firmware logic, ROS 2 software stops, and Nav2 collision monitoring to cut motor power and halt motion safely across all system layers.

Integrating an e-stop involves wiring a normally closed button to an MCU, publishing an /emergency_stop topic, and configuring Nav2 collision monitor to prevent unsafe motion through a high-priority velocity ban.

MCU firmware detects the e-stop trigger via an interrupt service routine, zeros PWM outputs immediately to cut power, and blocks motor re-enabling until an explicit acknowledgment path clears the state.

Yes, a physical normally closed e-stop pushbutton is required to cut motor power directly and trigger the safe shutdown sequence, serving as the foundational hardware layer for the multi-layer safety halt.

A high-priority velocity ban on the command mux is needed to override all navigation commands instantly, ensuring the robot halts motion safely when the emergency stop is activated.

Software-only stops lack fail-safe power cutting, making them insufficient alone; a robust system requires hardware e-stop buttons and MCU logic to physically cut motor power for guaranteed operator safety.