Looks like this might get lost, so I hope to help get it going....
I would imagine that the most difficult part would be getting the
mechanical engineering / handling correct.
1) Is this your own mechanics ?
2) How are you managing damping of the system?
i.e. When the tray 'hits' the load cell.
3) Are you sure it's not resonant / resonating ?
Have you tested for resonance ?
See damping.
4) Can you correlate actuals with data at lower speeds ?
Post signal data as an example.
Suggestions
===========
I would suggest that you post a picture (It's worth a thousand words)
or two and some sample data, then you might get a fuller answer.
