Power & Force Limited or Speed & Separation Monitoring? — Veo Robotics

The key question whether your application is amenable to SSM is determining how far the human can be from the robot while it is moving, the Minimum Distance to Hazard (MDH).[1] In this case, the hazard is the robot, and a human must be far enough away while the robot is operating so that if the human were to approach the robot, it could stop safely before the human and the robot came into contact. This approach can be part of the application (where for example, the human performs a step on a workpiece carried by the robot) or unexpected (where the human and robot are near each other but do not interact during normal operation). Hence, there is a minimum distance (the MDH) at which the human must be while the robot is operating.

The MDH depends on robot speed, payload, pose, robot controller latency, and, of course, the dynamics and mechanics of the specific robot. Our previous work indicates that this MDH is at least 1-1.5m, for a wide range of robots, even at zero speed, as the MDH needs to include robot controller latency.[2] If the application incorporates such a distance, and the human can be at this MDH while the robot operates, we can proceed (Box 2, Figure 1). 

If the MDH condition cannot be met, perhaps some creative rethinking of the application is needed (Box 3, Figure 1). Maybe having the robot move at high speed or with the heavy payload away from the human or reconfiguring the workflow will allow enough distance between the robot and human. However, it may still be the case that the robot and the human have to be closer than the MDH while the robot is operating (perhaps from space constraints). In that case, it is bad news; the application cannot realistically be made collaborative, and physical fencing or guarding to keep the human and robot apart is likely necessary.

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