When the robot encounters a point in space which it physically cannot move to an error message is displayed on the teach pendant saying - "The robot cannot reach the requested pose".
This can happen due to the following circumstances -
The default approach motion point to the start of a weld sequence is out of bounds
The default depart motion point from the end of a weld sequence is out of bounds
There is a non-reachable point "saved" in the flow
Approach Point not Reachable
The robot performs an approach motion to the Start Point of every weld sequence by moving to a point in space 2" above the taught Start Point before moving to the actual start of the weld. If the Start Point captured is close to the outer bounds of the robot's workspace, the robot may fail to perform the default approach motion and display an error message on the teach pendant
Adding an "air move" at a desired point within 2" of the start of the weld will allow the robot to bypass the default approach motion and move the taught "air move" point before traveling to the start of the weld.
Depart Point not Reachable
Similar to the approach, the robot performs a depart sequence where it backs up 2" from the end point of a weld if there is no "air move" before this distance. Again, if the End Point of the weld sequence is close to the robot's workspace limits, the default depart motion sequence fails and an error is displayed.
Add a reachable "air move" point within 2" of the end of the weld sequence so that the default depart motion is bypasses. The robot will move the saved "air move" point instead of the performing its depart sequence.
Non-reachable Point Saved in the Flow
In rare cases where a "corrupted" point is stored in the database, the robot will display an error message indicating that the point is not reachable. In this case, the user will have to fix the non-reachable point by using the "Move Here" feature in the beacon app to the highlighted point and verify that robot can physically move there. If not, the point has to be touched up by reteaching it.
The image below shows the point in the flow at which a non-reachable point was detected by the robot and execution was halted.
For more information regarding the robot's workspace limits, please refer to this article.