SCARA is moving too slow

I was trying to Trace movement of SCARA, purely simulation, it was not on real system. I used CNC program for basic rectangle, that I am certain that works just fine and I did trace this:

The speed really is not nearing my wanted 1m/s and the movement is not fully linear. I thought that the acceleration/deceleration was not fast enough. The axes are set in degrees with maximum speed of 1000units/s and acceleration/deceleration was both on 1000units/s^2. I increased the acceleration and deceleration to 10 000units/s^2, but the traced data is the same. Are there some limits inside the calculations itself that I am not awere of, or is there some other file where I can change the speeds beside this? Both axis Q1 and Q2 are set the same way, so it should not be because one axis is faster then the other.

@jan.wolf what’s your feedrate setting?

The Feedrate is units/min so mm/min. For example: 150000 mm/min = 2500 mm/sec = 2.5 m/s

My feedrate is 60 000, so it should be 1000mm/s = 1m/s. Even in the uper graph I can see the Function block was getting request for 1000mm/s (the purple line -ProgrammedPathVelocity above the orange trace - CurrentPathVelocity)

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Also to add more info, I did try different feedrates as well, but anything above 0,5m/s will make the same trace. Thats why I asked if there are some other configuration files with limits in case they are trying to overwrite each other

Have you checked your axis velocities and accelerations and if you reach their limit? You can use a formula in mapp Cockpit to derive them from your joint axes positions.

Not sure if this can be an issue, but with 0.00001 your measurement resolution is set quite low as well. We usually use 0.001

There are some axis group features that allow for further limitations of the path, make sure you have only features referenced in your axis group configuration that you actually want to use.

Regarding the non-linearity, what do you use to visualize the robot? Are you sure the kinematic dimensions are entered correctly both in the simulation and the mechanical system?

Do you get logger entries, something similar to “Undesired stops on path”? This can be a result of wrong configured “limit check resolution” and “buffer size” in the trajectory settings in the axes group configuration.

Hope some of the input helps

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I tried to move just with the axis, not the axis group and that reached 1000mm/s.
I showed the speed (top) and acceleration (bottom), but it doesnt reach the maximum, when I started CNC program.

I switched to 0.001 resolution but it did not change result.

As for the features, I am not using any, I am only using the default options.
image
The only limits are in the axis itself and in mechanical system it is set to use axis limits.

As for visualization, I am not really sure what do you mean, but I am using the integrated scara.
image

As for the logger, I am not getting anything regarding the stops on path.

Hi Jan,

I believe you have set too low limits for the QC axis. I suspect that Q1 and Q2 have rather high velocity and acceleration limits while QC is limited in speed and acceleration.

If you programs G01s X=something Y=something, then the system keeps the C orientation constant which means it must rotate QC as well during linear interpolation.

But, if QC is limited in its dynamics, then the overall movement needs to slow down as well. Which is intended.

Give it a try :wink: And please let us know it helps.

Regards,
Roland

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Hi Roland,

Yes, thank you! It was really the solution. I increased teh velocity and acceleration and now it is working just fine. I thought since I virtualised the axis QC, I do not need to pay attention to it anymore. :sweat_smile:
Again, thanks for help!

Regards,
Jan

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Hello,

you may set the solution for this thread to mark it as solved.

In addition i like to add that for high dynamic applications it might be nessesary to change the LimitCheckResolution to smaller Values, as this Value has some influence how fast the PathVelocity can change and how good the limits are used. But keep in mind that the LimitCheckResolution is also bound to the maximum StopTrajectory and the cpu load.

Greetings
Michael

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