ARC200 Hydrofoil Testing

Discussion in 'ARC Universal Motor Drive' started by Jeremy Elliott, Jan 25, 2019.

  1. Jeremy Elliott

    Jeremy Elliott New Member

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    I have been luck enough to get an ARC200 to test on my electric hydrofoil! Currently it is pretty cold and gloomy in the UK and I am testing indoors with various motors to see how the drive handles them. The motors are as follows:

    - 6384 100KV outrunner (will make an attempt at a direct drive unit)
    - 5674 750KV inrunner (will run through a gearbox)
    - 56114 500KV inrunner (will be used with a jet drive)

    Thus far I have configured each motor for the drive and run some basic tests.

    The 100KV outrunner I have coated in corrosion X and tested in the bath tub. Here is a short video from the tests: https://scontent-lht6-1.cdninstagra...n.mp4?_nc_ht=scontent-lht6-1.cdninstagram.com

    Config wise I am running the drive in torque mode with a jitter start.

    I have found some weird results with the 500KV and 750KV motors though and have some questions I hope someone can answer...

    • In Torque mode with forward only, sometimes the motor will carry on spinning for ages by itself, is this normal behaviour?
    • In speed mode, the start up and slow down are very slow, how do I adjust the start up ramp and slow down ramp of the ESC?
    • How do I set a failsafe on the ESC (this might be in docs, but I haven't found it)?
    • On both the 500KV and 750KVI hear some strange ‘clicking’ noises when the motor is running, any idea what they could be?
    • The 750KV seems to get to a max speed and then slow down a little, is that the Max ERPM of the drive that is slowing it down a bit?
    If anyone has any question or tests they would like me to run, just let me know :)
     
  2. Tyler Christensen

    Tyler Christensen New Member

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    In Torque mode with forward only, sometimes the motor will carry on spinning for ages by itself, is this normal behaviour?

    Do you mean the motor keeps spinning even with a zero torque command? This is normal although fixable. What's probably going on is there are slight current offset biases in the measurement, so when you command 0A, it might still be providing a few amps of torque due to sensor offsets. This means that if the prop were under water, it'd most likely stop or slow down with a 0A command for this configuration. To make this problem go away or get much better, if you make the "Current Command Offset" parameter in the A. Control section a higher negative number (default is -0.15), it'll be more inclined to stop for a 0A current command.

    In speed mode, the start up and slow down are very slow, how do I adjust the start up ramp and slow down ramp of the ESC?

    This is setup with the "Slew Up" and "Slew Down" parameters in the H. RPM Loop section. Defaults are very low to make autotune a gentle and reliable process but you can set these much higher (although as you go up, speed and current loop tuning become more and more important, at some point you may find an instability).

    How do I set a failsafe on the ESC (this might be in docs, but I haven't found it)?

    The failsafe is not configurable. If you're using PWM control, then if the cable gets unplugged or PWM signal disappears, in speed mode it commands 0RPM (rapid stop) or in torque mode it commands 0A (no torque). If you're using analog control, the failsafe ensures that the signal is internally pulled down, so whatever a 0V analog signal does will be the failsafe result. Make sure you are running the latest firmware, there was a bug in earlier firmwares that made PWM failsafe ineffective. (Firmware update is here: https://freeflysystems.atlassian.net/wiki/spaces/FRP/pages/269320215/Arc200+Firmware+Updates)

    On both the 500KV and 750KVI hear some strange ‘clicking’ noises when the motor is running, any idea what they could be?

    Can you post a video of this? I can't tell you from that description but may be able to from a video. I was unable to view your video link (it says "URL signature expired").

    The 750KV seems to get to a max speed and then slow down a little, is that the Max ERPM of the drive that is slowing it down a bit?

    Arc200 has no enforced max ERPM. If you quickly accelerate the motor, it is normal for the max speed to overshoot a little (usually for a half a second or so). This is just due to the control dynamics of the current loops, there is brief field weakening which makes the speed go a tiny bit higher than is possible in steady-state. This is generally nothing to worry about, if you post a video of that too I can confirm that's what's going on.
     
  3. Jeremy Elliott

    Jeremy Elliott New Member

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    I have upgraded to the latest 1.18 firmware, however the failsafe is still not working. If I switch off my TX or if there is a signal loss, the ESC goes to full throttle. This is a major problem!
     
  4. Tyler Christensen

    Tyler Christensen New Member

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    Can you post your configuration file so I can take a look at it? Also just to be 100% sure, can you actually unplug the receiver from the motor drive while it's running rather than switch off the TX? I think some of those receivers have programmable fail-safes so it might be going to a high-PWM failsafe which would need to be changed to a low-PWM failsafe to match up to Arc200's expectation.
     
  5. Jeremy Elliott

    Jeremy Elliott New Member

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    It appears that even though the failsafe was working on a different ESC, I did need to reset it for the ARC200. I managed to get it working properly thanks Tyler.

    Now I need to get onto making the other video's with the other motors for you to take a look at.
     
  6. Jeremy Elliott

    Jeremy Elliott New Member

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    Finally got the time to get a video.

    - You can hear some strange scratching noises, not too sure what it is. Motor bearings are fine.
    - When the motor is running full speed, sometimes it takes a while to register that the throttle has been dropped back down to nothing.
    - You can also hear that the motor makes a weird noise when at full throttle sometimes.
     
  7. Tyler Christensen

    Tyler Christensen New Member

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    There seem to be two sounds there. The one where it's sort of a weird tone wobbling in and out every few seconds is normal for Arc200 on certain motors and is just part of the operation of the control loop (it's usually much quieter than this, but certain motors get louder on that like in this video). The much louder sound that is more like a vibration sound I'm not quite as sure on. It is possible for a motor to have resonances even with pretty good tight bearings. If it's really not the motor, my next thing to look at would be the current loop as that's about the only thing with a high enough bandwidth to possibly make a high frequency vibration. Try the various selections in the Current Loop Tuning Wizard making sure to click Run before Save Results to actually run the tune math. That vibration noise may also improve when there's mechanical damping through the load of a prop in water.

    As for the throttle having delay, this is speed mode correct? If so I think what's going on is let's say the motor's max speed given the power supply voltage is 5,000RPM, but the drive is configured for a max speed of 10,000RPM. It seems you have a fairly slow speed slew-rate, let's say it's 2,500RPM/s. In that case, the drive's internal speed-command will ramp up to 10,000RPM while the motor is only spinning 5,000RPM due to voltage limitations. When you then zero the throttle, it takes 2 seconds for the internal command to get down to 5,000RPM again due to the slew rate limit, during which point you won't be noticing anything changing. The real fix here would then be to reduce the drive's max command RPM to match what the motor is actually capable of on the supply voltage so that the internal command doesn't saturate. You also probably wouldn't really notice this if the slew rate was higher since the delay would be much shorter, although that would just mask the issue in reality.
     
  8. Jeremy Elliott

    Jeremy Elliott New Member

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    Thanks for the response @Tyler Christensen
    Which RPM limit do I need to change in the config. The max RPM my motor should hit is around 37800 at 50.4V.
     
    #8 Jeremy Elliott, Feb 15, 2019
    Last edited: Feb 15, 2019
  9. Tyler Christensen

    Tyler Christensen New Member

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    When you're running it at full throttle as currently configured, go to the Telemetry tab and look at the "Speed" field. Take that number (which is the actual measured speed of the motor, there's not enough voltage to make it spin any faster) and go to the configuration tab, section H. RPM Loop, enter that as the Forward and Reverse RPM Command Max then send that config. See if that makes your problem go away on the throttle delay (I'm guessing the parameters for RPM command maxes are quite a bit higher than the actual measured max speed you will observe).
     
  10. Jeremy Elliott

    Jeremy Elliott New Member

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    Thanks @Tyler Christensen that solved it! I can't wait to get my board back now so that I can put it all together and test it on the water!
     
  11. Jeremy Elliott

    Jeremy Elliott New Member

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    Been a while so I thought I'd upload a few pictures...

    First the board:
    20190627_094946.jpg 20190627_095019.jpg 20190627_094322.jpg 20190627_094347.jpg

    The ARC200 is attached to this watercooled heatsink:
    239bf6464000c041d9c7925b0688121a38493e2a.jpeg
     
  12. Mattd

    Mattd New Member

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    Hi There !
    I'm Matt and a new customer of the Arc200 that we use for our hydrofoil. Tyler we just had our first try yesterday and I think we have some problem with the configuration of the Arc200. It was first in the RPM mode and seem to be weak at the startup and took too much time to slow down...and some cut off every time I wanted to stand up and the foil. I don't really know what's happening.
    I just review the all conf but you may advise us on our configuration and maybe see if there's a problem.
    We use the following setup:
    - 1 motor leopard hobby 56110 640KV with a neugart 5:1 gearbox
    - 4 batteries 6S 22.2V 8A to get 48.4V at 16A
    - 1 Arc 200

    I review the conf and it seems to be better, but I'd like to get your expertise and get a quick startup and a quick slowdown too and understand why we had some cut off.

    Could you please help us ? I past our configuration here...

    And what should we put as temprature limits ?

    Thanks,

    Matt
     
  13. Jeremy Elliott

    Jeremy Elliott New Member

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    Hi Matt

    Speed mode (RPM) is the correct mode to use.
    Your max theoretical RPM should be 32256rpm. So if you set the ARC200 higher than that, then it will think its pushing a higher RPM and have a delay before it slows down. You can check in the telemetry section what your max RPM is when running and then set it to that.
    Temp wise I set the max to 85 degrees celcius, but with water cooling I never go above 60. Here is my current config that I am very happy with (12S with 750Kv motor and 8:1 gear)

    comboParam$Control Mode$Speed Mode (RPM)
    numericParam$Current Command Offset$-0.15$A/(VDC * PWMdec)
    numericParam$Torque-Forward-Only Regen Foldback Start-Below PWM$5$% PWM
    numericParam$Smart Reversal Threshold$10$A
    numericParam$Smart Reversal Time$10$ms
    comboParam$Input Throttle Mode$PWM Throttle on Encoder Line
    numericParam$Input Throttle Min$986.25$ms if in PWM
    numericParam$Input Throttle Zero Neutral$986.25$ms if in PWM
    numericParam$Input Throttle Deadband$49.65625$+/- (ms if in PWM)
    numericParam$Input Throttle Max$1979.375$ms if in PWM
    numericParam$Input Brake Min$0$
    numericParam$Input Brake Max$65535$
    numericParam$Throttle Expo$0$%
    comboParam$Sensored vs. Sensorless$Sensorless
    comboParam$Sensorless Speed-Mode Startup$Ramp Mode
    comboParam$Sensorless Torque-Mode Startup$Jitter Start
    comboParam$Sensored Mode$3 Hall Sensor
    numericParam$Sensored Offset$1$
    comboParam$Sensored Hall Code$A (120 deg)
    numericParam$Sensored Abs. Encoder Min$0$
    numericParam$Sensored Abs. Encoder Max$65535$
    numericParam$Sensorless Transition Start$100000$RPM
    numericParam$Sensorless Transition End$150000$RPM
    numericParam$Quadrature Cal Current$0$A
    numericParam$Pole Pairs$3$Pairs
    numericParam$Resistance$11.52775$mOhms
    numericParam$Inductance$5.495114$uH
    numericParam$KV$0.0007892445$Vp/RPM
    comboParam$Direction Reverse$No
    numericParam$Overvoltage Cutoff$50.4$V
    numericParam$Overvoltage Foldback Start$49.4$V
    numericParam$Undervoltage Cutoff$38.4$V
    numericParam$Undervoltage Foldback Start$40.8$V
    numericParam$Max Battery Draw$150.0$A
    numericParam$Max Battery Regen$10$A
    numericParam$Max Phase Accel Current A$0$A
    numericParam$Max Phase Accel Current B$0$A
    numericParam$Max Phase Accel Current MIN$150.000$A
    numericParam$Max Phase Accel Current MAX$150.000$A
    numericParam$Max Phase Accel Available With Throttle$150.000$A
    numericParam$Max Phase Regen Current A$0$A
    numericParam$Max Phase Regen Current B$0$A
    numericParam$Max Phase Regen Current MIN$100$A
    numericParam$Max Phase Regen Current MAX$100$A
    numericParam$Max Phase Regen Available With Throttle$100$A
    numericParam$ESC Temp Cutoff$100$Deg C
    numericParam$ESC Temp Foldback Start$85$Deg C
    comboParam$Retransmit Commands via CAN as Primary?$No
    numericParam$Forward RPM Foldback Start$35000$RPM
    numericParam$Forward RPM Foldback End$35000$RPM
    numericParam$Reverse RPM Foldback Start$0$RPM
    numericParam$Reverse RPM Foldback End$0$RPM
    numericParam$RPM Closed Loop 1$333.3$RPM
    numericParam$RPM Closed Loop 2$166.7$RPM
    numericParam$Jitter Speed 1$30$RPM
    numericParam$Jitter Speed 2$60$RPM
    numericParam$Jitter Frequency$10$Hz
    numericParam$Jitter Current Multiplier$3$x
    numericParam$Jitter Advancement Time$50$ms
    numericParam$Ramp Current$50$A
    numericParam$Ramp Rate$100$RPM/s
    numericParam$DQ Park Filter$0$ms
    numericParam$Super-DQ Park Filter$5$ms
    numericParam$Q-Current Int A$0$V/(A-s)
    numericParam$Q-Current Int B$0$V/(A-s)
    numericParam$Q-Current Int MIN$3.34003$V/(A-s)
    numericParam$Q-Current Int MAX$3.34003$V/(A-s)
    numericParam$Q-Current Proportional$0.05011298$V/A
    numericParam$D-Current Int A$0$V/(A-s)
    numericParam$D-Current Int B$0$V/(A-s)
    numericParam$D-Current Int MIN$3.34003$V/(A-s)
    numericParam$D-Current Int MAX$3.34003$V/(A-s)
    numericParam$D-Current Proportional$0.05011298$V/A
    numericParam$Q-Current Int Startup$3.34003$V/(A-s)
    numericParam$Q-Current Proportional Startup$0.05011298$V/(A-s)
    numericParam$RPM Deriv Filt$0$ms
    numericParam$Super-Diff$0$Vs^3/RPM
    numericParam$Forward RPM Command Max$35000$RPM
    numericParam$Reverse RPM Command Max$0$RPM
    numericParam$Slew Up A$0$RPM/s
    numericParam$Slew Up B$0$RPM/s
    numericParam$Slew Up MIN$20000$RPM/s
    numericParam$Slew Up MAX$20000$RPM/s
    numericParam$Slew Down A$0$RPM/s
    numericParam$Slew Down B$0$RPM/s
    numericParam$Slew Down MIN$40000$RPM/s
    numericParam$Slew Down MAX$40000$RPM/s
    numericParam$KP Up A$0$A/RPM
    numericParam$KP Up B$0$A/RPM
    numericParam$KP Up MIN$0.02$A/RPM
    numericParam$KP Up MAX$0.02$A/RPM
    numericParam$KP Down A$0$A/RPM
    numericParam$KP Down B$0$A/RPM
    numericParam$KP Down MIN$0.02$A/RPM
    numericParam$KP Down MAX$0.02$A/RPM
    numericParam$RPM Integrator$0$A/(RPM-s)
    numericParam$RPM Integrator Max$0$A
    numericParam$Thrust Drag$0$A/RPM^2
    numericParam$Angle P Gain$1$RPM/Deg
    numericParam$Angle D Gain$1$RPM-command/RPM
    numericParam$Flux VIR HPF$500$ms
    numericParam$Flux VIR LPF A$0$ms
    numericParam$Flux VIR LPF B$0$ms
    numericParam$Flux VIR LPF MIN$10$ms
    numericParam$Flux VIR LPF MAX$10$ms
    numericParam$Sensorless Angle Filter$4$ms
    numericParam$Speed Filter$6$ms
    numericParam$Minimum Diff Flux$0.00062825$Delta-Wb
     
  14. Mattd

    Mattd New Member

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    Hi Jeremy,

    Thank you for your quick answer and for sharing your conf, really appreciate it. You're right my engine run at around 30 000 rpm.
    I will update my conf and see if it suits the board better.
    Any chance I could find what was this kind of cut off ? I checked on the logs but didn't manage to see something relevant...

    Cheers,

    Matt
     
  15. Mattd

    Mattd New Member

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    Hi,
    We experienced bad performance from our Efoil. We didn't manage to stand up and use the foil and we didn't go above the 3 mph....
    Just realise that we are limited by our configuration of the arc200 up to 50A where we should boost at least 150A.
    We use a leopard hobby 56110 640KV, I don't really know how to change it, but I would like to increase it up to 150A. Could you please help me to change my conf ?

    comboParam$Control Mode$Speed Mode (RPM)
    numericParam$Current Command Offset$-0,15$A/(VDC * PWMdec)
    numericParam$Torque-Forward-Only Regen Foldback Start-Below PWM$2$% PWM
    numericParam$Smart Reversal Threshold$10$A
    numericParam$Smart Reversal Time$10$ms
    comboParam$Input Throttle Mode$PWM Throttle on Encoder Line
    numericParam$Input Throttle Min$900$ms if in PWM
    numericParam$Input Throttle Zero Neutral$1002,312$ms if in PWM
    numericParam$Input Throttle Deadband$250$+/- (ms if in PWM)
    numericParam$Input Throttle Max$1977$ms if in PWM
    numericParam$Input Brake Min$0$
    numericParam$Input Brake Max$65535$
    numericParam$Throttle Expo$0$%
    comboParam$Sensored vs. Sensorless$Sensorless
    comboParam$Sensorless Speed-Mode Startup$Ramp Mode
    comboParam$Sensorless Torque-Mode Startup$Jitter Start
    comboParam$Sensored Mode$3 Hall Sensor
    numericParam$Sensored Offset$1$
    comboParam$Sensored Hall Code$A (120 deg)
    numericParam$Sensored Abs. Encoder Min$0$
    numericParam$Sensored Abs. Encoder Max$65535$
    numericParam$Sensorless Transition Start$100000$RPM
    numericParam$Sensorless Transition End$150000$RPM
    numericParam$Quadrature Cal Current$0$A
    numericParam$Pole Pairs$2$Pairs
    numericParam$Resistance$11,7449$mOhms
    numericParam$Inductance$6,040223$uH
    numericParam$KV$0,0009629073$Vp/RPM
    comboParam$Direction Reverse$No
    numericParam$Overvoltage Cutoff$50,4$V
    numericParam$Overvoltage Foldback Start$50$V
    numericParam$Undervoltage Cutoff$38,4$V
    numericParam$Undervoltage Foldback Start$40,8$V
    numericParam$Max Battery Draw$50$A
    numericParam$Max Battery Regen$50$A
    numericParam$Max Phase Accel Current A$0$A
    numericParam$Max Phase Accel Current B$0$A
    numericParam$Max Phase Accel Current MIN$50$A
    numericParam$Max Phase Accel Current MAX$50$A
    numericParam$Max Phase Accel Available With Throttle$50$A
    numericParam$Max Phase Regen Current A$0$A
    numericParam$Max Phase Regen Current B$0$A
    numericParam$Max Phase Regen Current MIN$50$A
    numericParam$Max Phase Regen Current MAX$50$A
    numericParam$Max Phase Regen Available With Throttle$50$A
    numericParam$ESC Temp Cutoff$95$Deg C
    numericParam$ESC Temp Foldback Start$85$Deg C
    comboParam$Retransmit Commands via CAN as Primary?$No
    comboParam$Disable BTLE$No
    numericParam$Forward RPM Foldback Start$40000$RPM
    numericParam$Forward RPM Foldback End$50000$RPM
    numericParam$Reverse RPM Foldback Start$40000$RPM
    numericParam$Reverse RPM Foldback End$50000$RPM
    numericParam$RPM Closed Loop 1$333$RPM
    numericParam$RPM Closed Loop 2$166$RPM
    numericParam$Jitter Speed 1$30$RPM
    numericParam$Jitter Speed 2$60$RPM
    numericParam$Jitter Frequency$10$Hz
    numericParam$Jitter Current Multiplier$3$x
    numericParam$Jitter Advancement Time$10,0$ms
    numericParam$Ramp Current$50$A
    numericParam$Ramp Rate$1000$RPM/s
    numericParam$DQ Park Filter$0$ms
    numericParam$Super-DQ Park Filter$5$ms
    numericParam$Q-Current Int A$0$V/(A-s)
    numericParam$Q-Current Int B$0$V/(A-s)
    numericParam$Q-Current Int MIN$3,34003$V/(A-s)
    numericParam$Q-Current Int MAX$3,34003$V/(A-s)
    numericParam$Q-Current Proportional$0,05011298$V/A
    numericParam$D-Current Int A$0$V/(A-s)
    numericParam$D-Current Int B$0$V/(A-s)
    numericParam$D-Current Int MIN$3,34003$V/(A-s)
    numericParam$D-Current Int MAX$3,34003$V/(A-s)
    numericParam$D-Current Proportional$0,05011298$V/A
    numericParam$Q-Current Int Startup$3,34003$V/(A-s)
    numericParam$Q-Current Proportional Startup$0,05011298$V/(A-s)
    numericParam$RPM Deriv Filt$0$ms
    numericParam$Super-Diff$0$Vs^3/RPM
    numericParam$Forward RPM Command Max$30000$RPM
    numericParam$Reverse RPM Command Max$30000$RPM
    numericParam$Slew Up A$0$RPM/s
    numericParam$Slew Up B$0$RPM/s
    numericParam$Slew Up MIN$80000$RPM/s
    numericParam$Slew Up MAX$80000$RPM/s
    numericParam$Slew Down A$0$RPM/s
    numericParam$Slew Down B$0$RPM/s
    numericParam$Slew Down MIN$80000$RPM/s
    numericParam$Slew Down MAX$80000$RPM/s
    numericParam$KP Up A$0$A/RPM
    numericParam$KP Up B$0$A/RPM
    numericParam$KP Up MIN$0,05$A/RPM
    numericParam$KP Up MAX$0,05$A/RPM
    numericParam$KP Down A$0$A/RPM
    numericParam$KP Down B$0$A/RPM
    numericParam$KP Down MIN$0,05$A/RPM
    numericParam$KP Down MAX$0,05$A/RPM
    numericParam$RPM Integrator$0$A/(RPM-s)
    numericParam$RPM Integrator Max$0$A
    numericParam$Thrust Drag$0$A/RPM^2
    numericParam$Angle P Gain$1$RPM/Deg
    numericParam$Angle D Gain$1$RPM-command/RPM
    numericParam$Flux VIR HPF$500$ms
    numericParam$Flux VIR LPF A$0$ms
    numericParam$Flux VIR LPF B$0$ms
    numericParam$Flux VIR LPF MIN$10$ms
    numericParam$Flux VIR LPF MAX$10$ms
    numericParam$Sensorless Angle Filter$4$ms
    numericParam$Speed Filter$6$ms
    numericParam$Minimum Diff Flux$0,0011495$Delta-Wb

    Thank you

    Matt
     

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