What is Hazardous Motion and how is it mitigated in robot safety?

• A. Planned movement that is risk-free when operators are trained
• B. Movement only occurs during maintenance
• C. Unexpected or unplanned movement that can injure workers; mitigated by guarding, safe speed control, protective stops, and interlocks.
• D. Motion hazards are resolved by post-incident reporting

Answer: (C)

Hazardous motion means movement by a robot or its tooling that can injure workers when it happens unexpectedly or outside safe boundaries. The risk is highest when people are near moving parts or when a system can move without warning due to a fault or control issue. The best way to mitigate this is through protective measures built into the system: guarding to physically separate workers from moving parts; safe speed control to keep motion within limits that are safe for nearby people; protective stops that can halt motion if needed; and interlocks that ensure safety devices are engaged before motion can start or while access gates are open. These engineering controls reduce exposure to motion hazards during normal operation. Other ideas, like trusting training for planned movements or restricting motion to maintenance only, don’t address the risk of unexpected movement in everyday work, and post-incident reporting doesn’t prevent the hazard from occurring in the first place.