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Adaptive Control - is this working at all?


sutty

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Hi!

It's one axis. Did tuning unloaded. IDE-Tune-tool says: NominalGain=4800 (unloaded) resp. 550 (loaded with 21,94 kg)

Servo: 16kHz

RTI: 2 kHz

Topology: Motor #4 and Motor #24 (put-through only) cascaded

Set Adaptive-Control-Parameters:

Motor[4].Servo.NominalGain=4800
Motor[4].Servo.EstMinDac=100
Motor[4].Servo.EstTime=160
Motor[4].Servo.MinGainFactor=1
Motor[4].Servo.MaxGainFactor=9
Motor[4].Servo.MinW=0
Motor[4].Servo.MaxW=0
Motor[4].Servo.MinDR=0
Motor[4].Servo.MaxDR=0

Put load with 21,94 kg (total of 100 kg possible) on.

Motor[4].Servo.GainFactor remains all time at 1!!

Motor[4].Servo.EstGain wont go above 0.02

Lowering MinGainFactor would lower GainFactor during accel/deceleration equally to MinGainFactor

By the way setting MinGainFactor = MaxGainFactor = 9 would give a nice and stable setup with 21,94 kg load.

I am really rookie-like - but can anybody show me a good practice example?!!

Would I absolutely have to also set MaxW, MinW, MaxDR and MinDR?

Thanks and regards,

Anton

 

 

Edited by sutty
added motor-topology
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MaxW, MinW, MaxDR and MinDR are only used if you intend to implement “Gain Scheduled Adaptive Control”.

I might suspect that at your servo frequency of 16KHz your setting of Motor[4].Servo.EstTime=160 may be too low to acquire sufficient “good data”. The “Power PMAC User’s Manual” suggests 100-500 at the default servo rate of 2.26KHz. Your servo rate is seven times faster. See if increasing this provides better results.

 

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Hi Steve!

I rised EstTime up to 3000 - no improvments at all.

I have to mention again that that ABS(Motor[4].Servo.EstGain) wont rise above 2e-2 in no case.

Motor[4].Servo.NominalGain=4800
Motor[4].Servo.EstMinDac=100
Motor[4].Servo.EstTime=300
Motor[4].Servo.MinGainFactor=1
Motor[4].Servo.MaxGainFactor=5

image.thumb.png.45c8e584aca336bff0f94ff4a32e5a5e.png

 

Motor[4].Servo.NominalGain=4800
Motor[4].Servo.EstMinDac=100
Motor[4].Servo.EstTime=3000
Motor[4].Servo.MinGainFactor=1
Motor[4].Servo.MaxGainFactor=5

image.thumb.png.ec0b5bf2bf0da4a48c45bc6bea370e1d.png

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Yes, it is!

When I set Motor[4].Servo.MinGainFactor = Motor[4].Servo.MaxGainFactor (which forces Motor[4].Servo.GainFactor to that value) = "GainFactor" I calculated according several NominalGain-estimations, and it works from 0 to 100 kg.

For example I tune the 100kg system. Estimate Nominal Gain for 100 kg (around 50) and for 22kg (around 500). So I set Motor[4].Servo.MinGainFactor = Motor[4].Servo.MaxGainFactor = 50/500 = 0.1 which forces Motor[4].Servo.GainFactor = 0.1.

Might the cascading of motor #4 and #24 be a issue?

Edited by sutty
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Hi Steve!

Unfortunately it is quite a deal to de-cascade the 2 loops. At least at the moment I cant spend time to do so. ... I will see in about 1 or 2 weeks and get back to you as soon I know more..

However, Is there a strict no-go for cascaded loops?

Bye, Anton

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