CG position from 4 corner load cells

[trainguy]

All,

We are attempting to use 4 load cells at corners of a railcar to determine its CG.

Using 3 points instead (which I'd rather do because it's statically determinate) is not feasible.

A discussion on thread404-117973 touched on this. Does anyone have a repeatable method of establishing the CG position (in plan) using the 4 load cell readings? We even have the capability of raising and lowering 1 of the corners slightly and taking new readings. These additional ones could provide the missing equation!

Any ideas?

tg

 

[trainguy]

Amazing feedback all - thank-you.

Have been away on family related matters - but we succeeded in getting pretty good repeatability when weighing last week, using 4 load cells that have domed tops.

Will provide details soon.

tg

 

[chicopee]

A nearly similar analysis was requested in an old thread no. 404-279555, however, the request was to find the reactions at four corner points of an assumingly rigid, flat plate subjected to a load at a particular point. If you study my reply, it may provide an insight to a procedure related to your question. As stated above, railroad car spring deflections will tilt the car and that may or may not have to be taken into consideration depending on the accuracy that you would allow.