Abstract
This disclosure describes how a governed robot is stopped safely when the safest stop depends on what the robot is doing. Removing power at once is safe for a fixed arm moving nothing, but it can make a walking robot fall, drop a raised load, trap a person in a gripper or exoskeleton, or leave a person stranded mid-way in a lift or transfer. The independent safety plane therefore keeps, at all times, a safe-state map for the robot: from its posture, its load, its surroundings and the people nearby, it computes which stop category to use (removal of power, a controlled stop followed by removal of power, or a controlled stop holding position) and which final posture to reach, such as kneeling or sitting for a legged robot, lowering a load to a declared height, or opening a gripper away from a person. The map is computed in advance, so that it is ready when a stop is needed and does not depend on the robot's own control software. Actions that would move the robot into a state with no safe stop are refused before they begin. The stop chain is independent of the control software, and if the safety plane cannot reach a safe-state decision in time, it falls back to a declared safe default for the robot's class. Where a person is held or supported by the robot, the stop includes a release or a supported lowering that a person nearby can also operate by hand. After any stop, the robot may not restart until its cause is recorded and, for the higher safety profiles, approved. Stop behaviour in each posture and load is drilled on the robot's twin and periodically on the real machine. Every map, stop, release and restart is a signed record.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Wang, Edward D. H., "SI Robot Reset™: A Safe-State Map for Governed Robots, Computed Continuously by an Independent Safety Plane from Posture, Load, Surroundings and People Nearby, so that Each Stop Chooses the Stop Category and Final Posture that Leave No One Dropped, Struck, Trapped or Stranded, with an Independent Stop Chain that Falls Back to a Declared Safe Default, Release of Trapped People, No Restart without a Recorded Cause, and Stop Drills on the Twin and the Real Machine", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/12894