We have an RS050 on a 7th-axis (traverse axis) and are synchronizing with the conveyor. We are running into a problem related to the traverse axis limits. As they part moves into the zone, the "zero" position of the traverse axis increments. We need to initially process the part upstream at the start and then downstream at the end. The zero position of the 7th axis is at the start of the rail, so as the vehicle moves into the zone, we would need to program a negative value for the traverse axis to process "downstream". But the software and mechanical axis limits do not allow us to do this. How do we resolve this?
Kawasaki RS050 with Traverse Axis Conveyor Synch
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saprobot -
May 24, 2020 at 11:51 PM -
Thread is Unresolved
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Welcome to the forum...……..
Without knowing your configuration or code, it is difficult to speculate.
As they part moves into the zone, the "zero" position of the traverse axis increments.
Does this mean, the external axis is incrementally matched to the conveyor position.
ie - when the vehicle is detected, the conveyor encoder is reset and then axis 7 follows it
We need to initially process the part upstream at the start and then downstream at the end.
You should be conveyor tracking throughout the complete process, and if you are crossing a parallel that requires the external axis to go from a positive value, through zero and then into a negative value, then this suggests to me, the external axis has not been correctly configured.
You should usually conveyor track in one direction only and usually the same direction.
But as mentioned, without knowing your configuration or code, it is difficult to speculate.
If you could provide some more specific details, it may help.
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Thank you. Please let me provide some more detail. This is for a typical production line where the conveyor is parallel to the 7th-axis traverse unit (rail). The part detect is upstream of the traverse axis about 2m, and there is a wait conveyor statement that holds the robot until the part just enters the zone. Conveyor synchronization is activated, and the robot properly synchronizes with the conveyor for the first process. For the first process, we are reaching upstream. So, for the robot on the right hand side of the conveyor, the robot is reaching to it's left. Later in the process, we want to process downstream so the robot reaches to its right. This is where the problem occurs. In our system, the 7th axis position is synchronized with the conveyor, so as the conveyor travels, the 7th axis reference position travels. In our case, we want to start the 1st process with the robot near the start of the rail, at 100 mm. As you can see in the attachment, the process takes 15 seconds, so the robot travels 1500mm down the rail as it is synchronized. For the next process, we want to reach downstream. Since the robot is already 1600 mm downstream, we just want to move it back upstream 500 mm. In order to do this, we would need to program a 7th axis position of a negative value (-400), which we are not allowed to do because it is below the lower axis limit of zero.
On other robot systems, the programmed 7th axis values do not need to fall within the software/mechanical limits of the rail unit when synchronized with the conveyor, but the system knows when the physical robots reach the limit. I suspect that Kawasaki is the same, so I suspect we have something configured incorrectly. I'd appreciate any ideas you may have.
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Thanks for the image and details, but there is too much to read...where is the code and the robot and external axis....above the conveyor, or below it?
- I assume its above due to your 'pointing right and pointing left references', but I could be wrong.
Other systems have no bearing here and to approach the application assuming all systems are the same is naïve and fundamentals get missed.
1. Are you in possession of conveyor tracking manuals.
2. Programming in BLOCK or AS
3. It appears you wish to track 2 different positions on the conveyor, (pointing right, the pointing left).
4. So you have 2 tracking postures to determine, relative to the conveyor position.
- 1st posture is sync'd with the part detection and conveyor position reset (pointing left - upstream)
- 2nd posture needs to be sync'd with the current conveyor position but 1600 - 1100, but include a new posture (JT1 - JT6) (pointing right - downstream).
5. Just repeat what you did with the 1st posture in the code and apply the correct math/instruction to set the 2nd posture.
Attached is the specific 'rule' associated with external axis (JT7) location data adjustment.