NI-Motion sinusoidal velocity profile

[cterrill]

Hello. I'm crossposting this question from the NI forums (here: http://forums.ni.com/t5/Motion-Control-and-Motor-Drives/Creating-a-sinusoidal-velocity-profile-with-PCI-7354/td-p/3142856 ). I'm working with a PCI-7354 board and attempting to create a custom sinusoidal velocity profile for two different motors to run simultaneously. I've been trying to run a simple 1D sinusoid using a contoured move in Motion Assistant with a PVT (position-velocity-time) profile. Due to the way the PVT profile calculates trajectory, I've ended up with a giant zigzag velocity profile that makes the motor jerk and jitter quite a bit. A screenshot of this can be found in the linked thread. I tried using a 1D position profile of a sine wave, but the velocity profile in Motion Assistant became a square wave.

 

I may be missing something simple here, but is there a way to simply create my own velocity profile and input it? If not through Motion Assistant, surely there's a way to do it using the Motion VIs in LabVIEW. Additionally, the 2D PVT move in Motion Assistant only accepts a total velocity magnitude. Is there a way to perhaps run two 1D profiles in parallel, maybe with one triggering the other at a certain point? I'd like to be able to modify one of them without having to mess with the other in the future.

 

Thanks!

[Jordan Kuehn]

Would you mind posting the PVT profile that generated this erratic behavior?

[cterrill]

The attached file "sample sinusoid.txt" is the initial file I tried. It created the profile from the screenshot in the linked NI forums post. The other attached txt file, "sample sinusoid 2.txt" is a different sinusoid with the amplitude increased to 10000 steps and the period shortened. I also rounded off all the values to the nearest whole number, in case decimal values were affecting the profile calculations. That yielded the attached screenshot.

 

Perhaps I should try increasing the time between points? It might smooth out the profile, but it doesn't particularly help with the actual application I'm working on, which requires a very specific velocity profile and very precise movement, which I'm worried will suffer as the time step increases.

sample sinusoid 2.txt

sample sinusoid.txt

[Jordan Kuehn]

I notice the first profile file has the velocity sinusoid starting at its peak while the position is at 0.  If I'm graphing it in excel correctly.  Perhaps swap these?