Metrology
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You are currently reading a thread in /g/ - Technology
Is anyone on this board well versed or semi knowledgeable in Metrology?
I have access to multiple FARO Arms at work, but they don't quite fill the need I have. Don't get me wrong, they're great and all but they certainly have their limits. Mostly talking about their physical reach.
I need to take measurements on a fairly large object, test said object, then measure the same points to find the deformation of various parts of the object. The FARO Arms work okay, but are very limited in this aspect and applicable to a few sections of the object, not every section needed. Due to this, I have to use plumb bobs, tape measures, and a laser level to take most of these measurements. Fairly archaic for the 21st century.
My question is, does anyone know of a CMM that can measure across large areas, 5 meters or so? I saw FARO has a system that uses optics, but it requires LoS, which won't work much better. In my researching, I found the DIY Drone community has come up with an Indoor Positioning System that looks like it could be modified to work. Basically set one fixed reference, then measure how far the points moved, up to 5m away.
>tl;dr Radio Based CMM
Basically looking for a GPS like system, except much more accurate, which I would assume is possible since it only needs to cover a SIGNIFICANTLY smaller area than GPS. Also willing to look into making my own system, but would like to see if another solution already exists. Google has nothing so far.
Basically thinking of something with 3 or more "towers" that send a signal to a receiver, which then uses the signals to triangulate a position, ideally with in a few millimeters. LoS not required, only being inside the coverage area of the towers. Seems like it should be do able, right?
Nice to see something /eng/ that isnt gpu, phone, or consumer electronicctap. What kind of accuracy are you looking for? If cm accuracy is ok and the part isnt metal, you could try magnetic field 6dof tracking systems. I use one at work made by polhemus.
>>55101831
I would prefer millimeter accuracy, but a cm might be okay. I mean, the system I use now is extremely archaic. Like I said, tape measures and laser levels.
Unfortunately the parts are a mix of materials, metal or plastic, but metal will always be present. Most of the metal measurements are capable with the FARO arm, the plastic ones not. One system to do both would be awesome, but I think two systems separate systems that provide an increase in precision and duplicity would be plenty good enough and provide an increase in speed enough to warrant the added system.
>>55101913
Unfortunately it is either some gigantic CMM, or some kind of optical tracking system with really small IR reflective stickers or something.
>>55101913
>>55101952
On second thought, maybe you can mount the arm on some linear postion track rail running around the object. Could probably rig that with some custom t-frame track/enclosure with linear carriages in each direction, and encoder strip or drawstring potentiometer to track position. At that point not sure if its worth the effort.
>>55101997
I had the same thought, some sort of overhead rail it rides on that's another potentiometer input for the Faro arm, but the time spent integrating it into the system, and voiding all sorts of warranties and never being able to calibrate it again probably exhausts more resources than it saves.
Anyone know of a technique I'm missing to deal with this situation? Maybe adding another reference point that can bolt and unbolt off the test subject that would let me zero closer to the deformation area?
I just found this thread and need to bump it because it makes me smile.
