Calibration & LabView

[roboticstudent]

Hello,

Need to calibrate an instrument that will later be used with LabVIEW.

Does anyone know of a measument instrument that meets the following requirements:

1) Resolution = 0.5 mm (no greater than this, but less is fine)

Range = 0-34cm (longer that this is fine)

Must be a non-contact measurement (i.e ultrasonic, laser,etc)

Thanks for any help. Please answer quickly, I need this answer yesterday.

[xseadog]

How long is a piece of string?

What type of application do you need to measure; voltage, current, temperature?

What type of instrument are you thinking of using ?
The list is endless.

Be more specific !!!

chow
xseadog

[Conseils]

Normally for non contact distance measurement over the range indicated a laser sensor such as Baumer Electrics (or similar)

http://www.baumerelectric.com/en/shop/catalog/Optoelektronische_Sensoren/page1.html?filter=yes&SM_Op...

would do the job, is the zero real or could it be 0 + an offset in which case the devices indicated would be entirely suitable.

The next thing that comes to mind is some kind of lens system as seen in a camera, I have seen these used but the ones I have used have been very pricey.

Message Edité par Conseils le 09-12-2005 08:50 PM

[roboticstudent]

The instrument being calibrated for measurement is a basically a industrial robot, such as the Zymark robot.

[Conseils]

So why do you have a zero contact issue?

Sorry I don't recognise the name immediately.

Heres an idea, set up a vernier caliper clamped at one both ends and move the robot through a distance (The force required is minimal, although it needs to be a straight line without correction).

Are you worried about calibrating it in three axis?

Does it operate on linear tracks or is rotating pivot type (is this why you are only after 0,5mm)?

[roboticstudent]

Thanks for all your help.  Currently what you have suggested is being implemented, but want a more accurate and precise measurement for validation.

[Conseils]

Well here's an alternate technique used in industry,

Fit a Renishaw (micron accuracy) touch probe (extremely sensitive) to the end of the robot arm, then using a length calibration bar you move the robot along and arrange to touch (or position) the bar at points giving known positions. Take your indicated position, your known position and compensate accordingly. {You may need to stop the robot when the switch or position sensor is triggered).

                   | Robot arm

                  o Touch probe or laser sensor etc

_____|XX|__________|XX|__________|XX|__________|XX|__________

known length positions............ Hope the graphic is clear..... its like the top of a castle wall.

The accuracy will depend on the position mechanisims, and the ability to determine when you have reached.

Don't forget that robots generally work in 3 dimensions so you position within a cubic volume which will probably vary over the volumetric capacity of the system, termperature effects, servo control error da.di.da.di.da........

Message Edité par Conseils le 09-12-2005 10:02 PM

[roboticstudent]

Thanks.  Will be working on all your good suggestions, and will try to report the results quickly.

[Conseils]

How did you progress with setting up your system?

Happy new year

[roboticstudent]

Hello,

Thanks for asking about my progress. I got caught up with the next phase of my project that I did not quickly update this message. Apologies.

The calibration of the instrument went very well.  Resolution and range requirements were quickly met by buying an instruments from the internet.  I was able to have a VI to get slope and intercept for me from the data gathered from the calibration. 

Now, I am trying to get that data into a database (MS Access), but because my data is 3D but contained in notepad (2D), I am having problems inserting my data into Access using the Database Connectivity toolset VIs.

If I can solve this problem, it is smooth sailing.  But till then...... I will be working at it.

Thanks again for inquiring about the project's progress.