Motor issues when running ESC calibration
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I understand that getting a vehicle up in the air for the first time is a complicated process and it can be frustrating at times. At this point, it looks like all the hardware is working properly, so there must be some PX4 parameter that is causing this behavior. We have not seen such behavior before, where the thrust is increasing very slowly (ramp) when RC command is maxed. Can you please check SYS_VEHICLE_RESP parameter?
Motor Outputs plot shows a linear ramp (slew-rate limited) when you raised the throttle to the max. The PX4 software is doing that.
Also please consider the following points:
- PX4 is a 3rd party software with hundreds of parameters and it has its own support forum. You should ask PX4 specific questions there.
- you have built a completely custom vehicle and bringing it up from scratch, so it is very difficult for us to support. This is not a standard vehicle that use for testing.
- we have provided support to make sure your hardware is operating properly and it seems to me that it is. If you feel there is still a hardware issue (ESC, VOXL2 boards, etc) or ModalAI software (not 3rd party software), please let us know.
Finally, if the original FPV ESC is still not communicating and there is no physical damage to it, i recommend that you submit an RMA and get a replacement ESC https://www.modalai.com/pages/rma . If you are going to do that, please put a note "Attn Alex K" so that I get the ESC and investigate what happened.
Alex
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I understand that getting a vehicle up in the air for the first time is a complicated process and it can be frustrating at times. At this point, it looks like all the hardware is working properly, so there must be some PX4 parameter that is causing this behavior. We have not seen such behavior before, where the thrust is increasing very slowly (ramp) when RC command is maxed. Can you please check SYS_VEHICLE_RESP parameter?
Motor Outputs plot shows a linear ramp (slew-rate limited) when you raised the throttle to the max. The PX4 software is doing that.
Also please consider the following points:
- PX4 is a 3rd party software with hundreds of parameters and it has its own support forum. You should ask PX4 specific questions there.
- you have built a completely custom vehicle and bringing it up from scratch, so it is very difficult for us to support. This is not a standard vehicle that use for testing.
- we have provided support to make sure your hardware is operating properly and it seems to me that it is. If you feel there is still a hardware issue (ESC, VOXL2 boards, etc) or ModalAI software (not 3rd party software), please let us know.
Finally, if the original FPV ESC is still not communicating and there is no physical damage to it, i recommend that you submit an RMA and get a replacement ESC https://www.modalai.com/pages/rma . If you are going to do that, please put a note "Attn Alex K" so that I get the ESC and investigate what happened.
Alex
@Alex-Kushleyev Good morning,
Started trouble shooting this issue again with no change.
Under 4s battery power, all motors respond well to motor test, using slider in QGC, min to full throttle in Actuator tab.
Still no response other than "slow ramp up" when throttle is increased on RC Tx.
RDJ
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@Alex-Kushleyev Good morning,
Started trouble shooting this issue again with no change.
Under 4s battery power, all motors respond well to motor test, using slider in QGC, min to full throttle in Actuator tab.
Still no response other than "slow ramp up" when throttle is increased on RC Tx.
RDJ
@rdjarvis , i wonder if you should try to load params for one of modalai standard vehicles and change the min/max rpm to match your setup (4000min, 40000 max, or you can be a bit more conservative, say 30k max for this test). Then try with manual control but with propellers OFF. The issue you are seeing is coming from Flight Controller so it should not matter of props are on or off for this test. But you should keep them off if using params from a completely different vehicle / tune. But at least you could then see if FC lets you raise the thrust normally..
Basically, no change to esc, props off, choose our standard vehicle params for 4s and try to raise thrust, check the px4 log.
If you see strange behavior like strong oscillations, you should stop the test.
If the thrust control is ok, then you can compare your params more carefully with our standard params and see what causes this behavior.
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@rdjarvis , i wonder if you should try to load params for one of modalai standard vehicles and change the min/max rpm to match your setup (4000min, 40000 max, or you can be a bit more conservative, say 30k max for this test). Then try with manual control but with propellers OFF. The issue you are seeing is coming from Flight Controller so it should not matter of props are on or off for this test. But you should keep them off if using params from a completely different vehicle / tune. But at least you could then see if FC lets you raise the thrust normally..
Basically, no change to esc, props off, choose our standard vehicle params for 4s and try to raise thrust, check the px4 log.
If you see strange behavior like strong oscillations, you should stop the test.
If the thrust control is ok, then you can compare your params more carefully with our standard params and see what causes this behavior.
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@Alex-Kushleyev I am going to upload FPV_REVB. unless you recommend another.
RDJ
@rdjarvis , yes but change the vbatt since fpv revb is 6s. That is probably closest to your config
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@rdjarvis , i wonder if you should try to load params for one of modalai standard vehicles and change the min/max rpm to match your setup (4000min, 40000 max, or you can be a bit more conservative, say 30k max for this test). Then try with manual control but with propellers OFF. The issue you are seeing is coming from Flight Controller so it should not matter of props are on or off for this test. But you should keep them off if using params from a completely different vehicle / tune. But at least you could then see if FC lets you raise the thrust normally..
Basically, no change to esc, props off, choose our standard vehicle params for 4s and try to raise thrust, check the px4 log.
If you see strange behavior like strong oscillations, you should stop the test.
If the thrust control is ok, then you can compare your params more carefully with our standard params and see what causes this behavior.
-
@rdjarvis , yes but change the vbatt since fpv revb is 6s. That is probably closest to your config
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What effect does the aO,a1, and a2 (pwm_vs_rpm curve) have on overall throttle response for FPV 4n1 ESC? in the FPV_RevB the a0 value is -161.0826?
@rdjarvis , please do not change ESC params that you tuned for your motors. I meant use px4 params from another vehicle.
The a0.,1,2 are params for feed forward term in rpm control. The esc seems to be working fine in your case (rpm tracking is good).
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@rdjarvis , please do not change ESC params that you tuned for your motors. I meant use px4 params from another vehicle.
The a0.,1,2 are params for feed forward term in rpm control. The esc seems to be working fine in your case (rpm tracking is good).
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copy all, will do.
@rdjarvis , sorry for confusion, please do not change esc params but find px4 tuning params for our fpv vehicle and try to load it to your vehicle (change 6s vbatt to 4s in px4 params since fpv vehicle uses 6s).
Test without props because attitude control is going tonbe much different for fpv vehicles vs yours. But you should still be able yo see thrust response in plots.
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@rdjarvis , sorry for confusion, please do not change esc params but find px4 tuning params for our fpv vehicle and try to load it to your vehicle (change 6s vbatt to 4s in px4 params since fpv vehicle uses 6s).
Test without props because attitude control is going tonbe much different for fpv vehicles vs yours. But you should still be able yo see thrust response in plots.
you can find our FPV params here :
Files · master · voxl / VOXL SDK / Utilities / voxl-px4-params · GitLab
PX4 parameter files for use on VOXL2 and Flight Core
GitLab (gitlab.com)
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you can find our FPV params here :
Files · master · voxl / VOXL SDK / Utilities / voxl-px4-params · GitLab
PX4 parameter files for use on VOXL2 and Flight Core
GitLab (gitlab.com)
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you can find our FPV params here :
Files · master · voxl / VOXL SDK / Utilities / voxl-px4-params · GitLab
PX4 parameter files for use on VOXL2 and Flight Core
GitLab (gitlab.com)
-
you can find our FPV params here :
Files · master · voxl / VOXL SDK / Utilities / voxl-px4-params · GitLab
PX4 parameter files for use on VOXL2 and Flight Core
GitLab (gitlab.com)
Throttle input is being "ignored" regardless of RC Channel input, same response (slow ramp up) when armed in any flight mode (Manual/Stab/Pos etc..) and throttle is increased, even when RC Channel is changed (1,2,3,4).
Motors respond correctly with pitch, yaw, and roll inputs.
PX4 FPV_RevBv4 params are uploaded, switched to 4S and put min/max RPM to 3000/40000.
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you can find our FPV params here :
Files · master · voxl / VOXL SDK / Utilities / voxl-px4-params · GitLab
PX4 parameter files for use on VOXL2 and Flight Core
GitLab (gitlab.com)
From the GCS, executed "take-off" command in "Position Mode" with props off. Motors smoothly increase. I "hand-flew" it up to 1m and UAV was adjusting for small movements correctly.
Executed "Land" and "hand-flew" it to the deck, landing detected and disarmed.
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From the GCS, executed "take-off" command in "Position Mode" with props off. Motors smoothly increase. I "hand-flew" it up to 1m and UAV was adjusting for small movements correctly.
Executed "Land" and "hand-flew" it to the deck, landing detected and disarmed.
@rdjarvis , interesting. Can you please share a px4 log from that position mode test?
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@rdjarvis , interesting. Can you please share a px4 log from that position mode test?
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@rdjarvis , yes in this mode, the vehicle seems to be responding to thrust commands and motors are tracking rpm well (even though without props)
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@rdjarvis , yes in this mode, the vehicle seems to be responding to thrust commands and motors are tracking rpm well (even though without props)
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@Alex-Kushleyev I agree, what do you think the next troubleshooting step is for this issue?
Also another observation.. remember in manual flight, it seemed like instead of responding to the throttle stick, the actuator outputs were going up slowly in a ramp -- i just double check that seems to be a response to small rill/pitch deviations that happened, so it seems that the thrust stick is COMPLETELY ignored, which is what you have suggested.
Now, the position mode goes through the same control pipeline except the hight is controlled using a high controller, as opposed to your radio. However, the commands are still going through the mixer that converts and thrust, roll, pitch, yaw commands to motor outputs , so that seems to be working correctly.
Based on that, it seems the issue is somewhere between the Actuator controls and motor outputs, which is the mixer, right? Actuator controls data shows the desired thrust (up) goes up, but motor output does not reflect this. Maybe we can look at the px4 source code for the mixer which maps the actuator controls to motor outputs.
I just noticed that you have parameters
CA_ROTORx_AZ(for x =0,1,2,3) set to 1, but default is -1, which would mean that you are saying that thrust from this motor goes up, not down?
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