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Define Velocity and Acceleration for a Motiontask using Custom Profile Tables

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Hello,

I have a question concerning AKD Servo drive. I implemented a python library to control the drive motion using the telnet protocoll and with your help it already works very well.

Now, I have issues with a specific feature:

First I define a non harmonic oscillating motion task, using a profile table, defined with a normalised curve shape, which is cut into two (due to its unsymmetric shape) which is uploaded to the drive. (please see attached photo)

Second I add velocity and acceleration to obtain the motion law and to fit the oscillation frequency. With iterative adaption of the velocitiess and accellerations I achieved the desired curve.

Problem:

Now I want to raise the frequency but keep the curve shape and the ratio between the two parts. Indeed the curves t0/t1 (ratio between first temporal part of the oscillation and second temporal part of it) is not constant.

How can I calculate the values for velocity and acceleration. It is obvious that he doesn't directly follow in terms of maxAngle/velocity = time, neither max acceleration for the given shape corresponds to the behavior.

Thank you in advance
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Hi Stewart,

Not sure I completely understand your issue, but I give it a try. I just setup a short test command for doing a similar motion like your drawing. This has been done by using profile table and the 1:1 curve. To achieve the slow acceleration and fast deceleration MT.ACC/DEC have been calculated.

MT.ACC = MT.V / time acceleration

MT.DEC = MT.V / time deceleration

image

This example uses the following values:

MT.NUM 8: MT.P = 90.0°, MT.V = 60rpm, MT.ACC = 160rpm/s, MT.DEC = 480rpm/s

MT.NUM 9: MT.P = -90.0°, MT.V = 150rpm, MT.ACC = 1000rpm/s, MT.DEC = 3000rpm/s

So the ratio between acc/dec stays but the oscillation frequency is adjusted. If adjusting the MT.ACC/DEC the ration could be changed. Also if you want the amplitude to stay the same the MT.V could stay the same and MT.P needs to reduced by what MT.ACC/MT.DEC are raised. So all adjustment of the oscillation should be possible.

Regards,

Martin

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