I receive this error when the flange gets close the lower arm (the link between the elbow joint and wrist 1 joint), event though there is at least 1,5cm between my tool and the arm. This error engage the protective stop mode.
Error C403A0: Danger of clamping between the robot lower arm and tool
Example of a configuration triggering the error:
I guess that the controller makes assumptions on the end effector shape, certainly for safety reasons, and prevents collisions between this shape and the arm links (note that I haven’t set any tool geometry or anything related to this in the safety settings).
In my case, I need to disable it, as I already handle collisions myself with the actual end effector shape.
Where does this error come from? I do not have anything related in my safety parameters (which are set to the default). Is there a way to disable it? If not, can I know precisely the conditions to trigger it (size of a collide box, joint limits, etc…)?
I use the UR5 e-series 5.8.
This error is in place because the UR robot is a collaborative robot. You will not be able to bypass this safety feature.
Avoiding this pinch point is a part of the collaborative nature of the cobot. The 1.5 cm sounds about right to prevent hand pinches.
Update: after multiple tests, we estimated that the security can be modeled by a cylinder around the forearm, and a sphere centered the flange with a padding of approximately 30mm. When those two shapes collides, the error is triggered.
This was later confirmed by Universal Robots, who precised the exact conditions: the error is triggered when a cylinder of radius 37,5mm around the forearm and a sphere of radius 37,5mm around the flange are at a distance of less than 28mm.
We entered those shapes in our trajectory planner and never encountered the error again.