More questions about the shuttle
It appears to me that these shuttles do have a mechanical rather than an individual drive, i.e. there is one drive motor for all four of them?
I guess this is why the tension of these 4 strings is incorporated to the overall mechanical equation of the device and once initialy set will never change.. if the string is intact.
My logic says that we need to capture the string at the position that is known and constant and I have presented a possible solution. This is the same point at which you have started (the arm).
The next thought is the answer to the question what happens when the (horizontal sock-wise) string breakes? Well, the vertical string feeders will miss capturing the broken string, will make it's up/down exchange and the next shuttle will lay the horizontal string in parralell with the previous horizontal string that worked (i.e. 2 horizontal strings will be captured together).. could we somehow detect that? E.g. a macro camera looking at the progress of the sock? Can it recognise the change in the pattern of the sock by some measurable means? Because the pattern will change. With one string missing there will be two strings captured together folowed by one captured alone in every full cycle of 360 degrees and this will continue for as long as there is one string missing..
Can you sample the production pattern against the correct image stored in the memory and and basing on this, make the decision to stop the process? The reasoning behind this is intuitive observation of things as they happen. A human observer will pick up the broken string by the change of pattern and nothing else. Maybe the sensor should do the same - observe the pattern.
Just a thought and a possible solution.
I am steering away from the shuttle monitoring, there is nothing there I can see that I can measure easily enough for a viable solution. Not only the string travells from one side of the spool to the other abut also the diameter of the spoll changes as the string is being used - what would capture that?
I guess the main problem is preventing you from sensing the tension of the string, it would possibly be - the easiest solution..
I'll be watching this thread (or string I should say
) with interest.
Regards,
xanadunow