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???
09/14/12 21:15
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#188335 - Precision is cheap ?
Responding to: ???'s previous message
Richard Erlacher said:
However, you have to consider what's considered quite adequate today.

Not many precise measurements are made at all, and those are "by guess and by golly" as they say, with roundoff done mentally, and so on.

Further, adjustments,....


Sure, but why design a system that guarantees more manual fix-ups are necessary ?
If you are going to the trouble to collect contour/pressure info, it seems not a good idea to limit precision by design.



I'm persuaded that a cone-shaped "virtual socket" with a length-adjustable framework of some sort, yet to be devised, would serve as the "track" on which this thing would travel. I expect the design of the physical mechanism might be a bit tricky. That's TBD, as yet.


I first thought of a 'U' track, then figured a large 'O' track might be more useful, as it allows two scan axis for 3D Contours.
A limb can go 'thru the hole' for scan, or in the same plane as the track.


List of 49 messages in thread
TopicAuthorDate
How would you do this?            01/01/70 00:00      
   I have no idea if this would work, but ....            01/01/70 00:00      
      How would one actuate them?            01/01/70 00:00      
   strain guage            01/01/70 00:00      
      Yes, you might be onto something.            01/01/70 00:00      
         Computer-controlled?            01/01/70 00:00      
            computer controlled            01/01/70 00:00      
               Calibration + redundant force-limitation            01/01/70 00:00      
               Interesting problem            01/01/70 00:00      
                  Yes, it seemed coarse, at first.            01/01/70 00:00      
                     Precision is cheap ?            01/01/70 00:00      
                        I don't follow ...             01/01/70 00:00      
                           Precision            01/01/70 00:00      
                              other considerations            01/01/70 00:00      
         Tomographic imaging?            01/01/70 00:00      
            There's one major problem ... maybe two ...            01/01/70 00:00      
               $100 MRI unit            01/01/70 00:00      
                  I'm not sure ...             01/01/70 00:00      
         Voice coil and LVDT?            01/01/70 00:00      
            Not having a lot of experience with this sort of stuff ...            01/01/70 00:00      
               Danger/problems with hydraulic since no spring effect            01/01/70 00:00      
                  A few things puzzle me with this approach            01/01/70 00:00      
   Ultra Sound Probing            01/01/70 00:00      
      Ultra-sound is better for measuring surface or sub-surface            01/01/70 00:00      
   I would not use volumetric imaging            01/01/70 00:00      
      I'm not sure what you mean            01/01/70 00:00      
         another thought            01/01/70 00:00      
            I consider that one of the more "pregnant" approaches            01/01/70 00:00      
               Lots of options available            01/01/70 00:00      
                  You've got to consider cost            01/01/70 00:00      
                     Cost/safety            01/01/70 00:00      
                     Cost target?            01/01/70 00:00      
                        The price target comes from a few prosthetists            01/01/70 00:00      
   comercial CMM            01/01/70 00:00      
      This only received cursory examination             01/01/70 00:00      
         pneumatic actuator            01/01/70 00:00      
            Yes ... but what would this cost?            01/01/70 00:00      
               100 rods?            01/01/70 00:00      
                  Patient size ...            01/01/70 00:00      
                     That's what I'm considering            01/01/70 00:00      
                     AAACK! ... another double post ...             01/01/70 00:00      
                  it's not as big as you think!            01/01/70 00:00      
                     90% coverage            01/01/70 00:00      
                        So maybe vacuum pump for the too fat people            01/01/70 00:00      
   I do not know if this is relevant, but            01/01/70 00:00      
      I'll have to look into this.            01/01/70 00:00      
         Single air pressure sensor sensor for tip force guestimate            01/01/70 00:00      
   What about infrared?            01/01/70 00:00      
      How would you do this so it would retail for under $5k            01/01/70 00:00      

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