Author Topic: Smoothing the trajectory to achieve higher velocity  (Read 577 times)

la001989

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Smoothing the trajectory to achieve higher velocity
« on: October 25, 2018, 01:32:15 AM »
Hi everyone,
I am currently using a KR 120 to simulate a 2D trajectory that I executed today. When we went up with our speed, we realized two things:
1) We started to get jerky point to point steps
2) Axis 4 turns 180 deg at a specific point and leads to a delay of the motion

For the first problem, we tried to make the steps bigger (Exclude each second point) and allow less accuracy by increasing "$APO.CDIS = 20" for our C_DIS. Then we tried PTP instead of LIN. The third idea was to change the initial condition of our gripper, to not have Axis 4 turn during our trajectory.

Does anyone have a better or different approach to smoothen our trajectory? we have only 20 points and I attached the linear and PTP SRC file.

Thank you very much for your help!!! 8)
L

Johannes @ Robots in Architecture

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Re: Smoothing the trajectory to achieve higher velocity
« Reply #1 on: October 25, 2018, 07:36:11 AM »
Hello,

There are a few things you can try, you already mentioned setting $APO.CDIS, however note that the highest value will be half the point distance - so if your points are closer than 40mm, your 20mm won't really have an increased effect.
If you want constant speed, consider setting the movement to C_VEL and using a high $APO.CVEL value (oercentage).
Also you could try using a spline movement, though I'm not really a fan of it.

However, the main issue is probably the A4 turning, which means that you are probably close to a singularity, i.e. the robot is stretched, in your case likely with A5 close to 0.
If you have a symmetrical tool like a pen or a milling tool, then rotate the planes around their tool axis, e.g. with the Orient Plane component. Alternatively change the position of your toolpath if you can, e.g. moving it up or down in relation to the robot.

Best,
Johannes