# Motor issues when running ESC calibration

Source: https://forum.modalai.com/topic/3318/motor-issues-when-running-esc-calibration
Category: ESCs, Sensors and Accessories (https://forum.modalai.com/category/15/escs-sensors-and-accessories)
Tags: esc
Posted: 2024-04-11 21:57:20 UTC by Alexander Saunders
Replies: 107 · Views: 65410

## Alexander Saunders · 2024-04-11 21:57:20 UTC

Good afternoon team,

My team and I are currently trying to run ESC calibration for a quadcopter drone. The equipment is a T-motor F2203.5 which has a rating of 3 -6s LIPO battery, a 4s LIPO battery, VOXL 2, and VOXL FPV ESC 4 in 1. When running the calibration on **outlet power** and following these documentation: https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md and using the command:$ ./voxl-esc-calibrate.py --id 0 --pwm-min 10 --pwm-max 95 the motor will run to completion and return the pwm vs rpm curve. When following the same procedure on **battery power**, the motor will reach about ~58 PWR before burning out. 

My question is what differences between the two power sources could potentially be causing this and could you point me to any additional documentation to troubleshoot? 

Any help is appreciated!

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-12 02:11:01 UTC

@Alexander-Saunders ,

Can you please clarify, what is "burning out" ? 

Also, on the FPV ESC, if you run the calibration procedure on esc ID 3, then you will also see the current measurement (on this ESC, there is only a total current measurement available and it is sensed by ID3).

When you are running the calibration using a power supply, is this power supply rated for the maximum current that the motor will draw during the calibration or is the voltage of the power supply reduced due to over current (as motor draws more and more current during calibration)?

Just to note (you probably already saw this), testing using power supply could sometimes lead to ESC failure, see https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md#hardware-setup (and specifically https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/doc/regenerative_braking.md). However, i understand that you are facing an issue and in this case it is OK to use a power supply, as long as it is rated for appropriate current for the test. The calibration procedure does not involve large steps, so there should not be regenerative braking spikes.

Can you share the plots that you got during calibration attempts using power supply  and battery? similar to these:
https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md#sample-calibration-results

If you are going to run this again, in order to avoid burning out (i assume motor), you can limit the `--pwm-max` to 50 or 55 to avoid any further issue so we can at least look at the plots that include current (and change the ESC id to 3 so we get current measurements -- make sure to install the propeller on ID3 instead):

```
./voxl-esc-calibrate.py --id 3 --pwm-min 10 --pwm-max 50
```

also, what propeller are you using?

## Reply by rdjarvis · 2024-04-12 16:20:53 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev said in [Motor issues when running ESC calibration](/post/16169):
> Can you please clarify, what is "burning out" ?
> 
> Also, on the FPV ESC, if you run the calibration procedure on esc ID 3, then you will also see the current measurement (on this ESC, there is only a total current measurement available and it is sensed by ID3).
> 
> When you are running the calibration using a power supply, is this power supply rated for the maximum current that the motor will draw during the calibration or is the voltage of the power supply reduced due to over current (as motor draws more and more current during calibration)?
> 
> Just to note (you probably already saw this), testing using power supply could sometimes lead to ESC failure, see https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md#hardware-setup (and specifically https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/doc/regenerative_braking.md). However, i understand that you are facing an issue and in this case it is OK to use a power supply, as long as it is rated for appropriate current for the test. The calibration procedure does not involve large steps, so there should not be regenerative braking spikes.
> 
> Can you share the plots that you got during calibration attempts using power supply and battery? similar to these:
> https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md#sample-calibration-results
> 
> If you are going to run this again, in order to avoid burning out (i assume motor), you can limit the --pwm-max to 50 or 55 to avoid any further issue so we can at least look at the plots that include current (and change the ESC id to 3 so we get current measurements -- make sure to install the propeller on ID3 instead):
> 
> ./voxl-esc-calibrate.py --id 3 --pwm-min 10 --pwm-max 50
> also, what propeller are you using?

Hello again Alex, I will help answer, Alex is on my team.

Can you please clarify, what is "burning out" ?
***The motor smokes and turns black within a few seconds while on battery pwr. fails to function smoothly***

Also, on the FPV ESC, if you run the calibration procedure on esc ID 3, then you will also see the current measurement (on this ESC, there is only a total current measurement available and it is sensed by ID3).

***thank you***

When you are running the calibration using a power supply, is this power supply rated for the maximum current that the motor will draw during the calibration or is the voltage of the power supply reduced due to over current (as motor draws more and more current during calibration)?

***Wall supply is 12V 3amp, just using for spin test, Battery is a 4S LiPo 60C 120C burst) Only doing motor calibration with Battery Power***

Just to note (you probably already saw this), testing using power supply could sometimes lead to ESC failure, see https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md#hardware-setup (and specifically https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/doc/regenerative_braking.md). However, i understand that you are facing an issue and in this case it is OK to use a power supply, as long as it is rated for appropriate current for the test. The calibration procedure does not involve large steps, so there should not be regenerative braking spikes.

***Motor does not sound smooth, lots of friction at all pwr levels when on ANY 4S battery. Motors operate as smooth as can be on wall power.***

Can you share the plots that you got during calibration attempts using power supply and battery? similar to these:
https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md#sample-calibration-results

If you are going to run this again, in order to avoid burning out (i assume motor), you can limit the --pwm-max to 50 or 55 to avoid any further issue so we can at least look at the plots that include current (and change the ESC id to 3 so we get current measurements -- make sure to install the propeller on ID3 instead):

./voxl-esc-calibrate.py --id 3 --pwm-min 10 --pwm-max 50
also, what propeller are you using?

***thank you for this Alex. We will be ready to make any changes today. This is a priority***

## Reply by Alexander Saunders · 2024-04-12 16:25:52 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Good morning Alex,

The plot before the motor burned was as follows:

Quadratic fit: motor_voltage = a2*rpm_desired^2 + a1*rpm_desired + a0
pwm_vs_rpm_curve_a0 = 5.03240880692
pwm_vs_rpm_curve_a1 = 5.75204182026
pwm_vs_rpm_curve_a2 = -0.000365638113773

We stopped testing for other motors because of the issues faced which is why there's only 1 instead of 4. 

Also we changed the params/tune used by the motors to more closely correspond to the T-motor F2203.5 and zeroed out the kp and ki params based off of this response: https://forum.modalai.com/topic/3179/seeking-assistance-with-motor-heating-and-burnt-smell-issue-on-new-drone

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-12 16:32:28 UTC (in reply to Alexander Saunders)

@Alexander-Saunders and @rdjarvis ,

the wall supply that can provide 3A is absolutely not enough to perform any motor testing, especially calibration. What happens if you try to do it, the wall supply will quickly reach its 3A limit and start decreasing output voltage, so the ESC cannot draw required power, so the calibration is useless (for lack of a better word). If you look at the voltage during the calibration stage, you will most likely see the voltage going into ESC will start dropping as soon as the power level will reach certain point at which the motor draws around 3A.

@Alexander-Saunders , i did not see the plot in your previous post - did you intend to attach an image of the plot?

Also, please provide a few more details to help me undrestand (i do have tmotor F2203.5 motor, so i can help you):
- what propeller are you using?
- what is the kV value of F2203.5 motor?

What could happen is that your propeller is too large for your motor or there are some tweaks we need to do to improve the ESC performance, which I can help with, but i need to know more details (above) and if you have any output from the terminal when the tests were running (it prints voltage, current, esc temperature, esc rpm, etc)

## Reply by rdjarvis · 2024-04-12 16:42:28 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Thank you for the fast reply!

T-Motor 2203.5 2850KV
3in 3052 Gemfan prop

Only used wall supply for spin test, not calibration.

## Reply by Alexander Saunders · 2024-04-12 16:46:39 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

The values I sent was the output. I did not send the visual plot of the feed curve because we turned our attention to debugging why the motor was not behaving as inspected. We are ssh into the voxl when running the test. I haven't done the steps of moving calibration_results.html to plot yet.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-12 19:44:05 UTC (in reply to Alexander Saunders)

@Alexander-Saunders , you just use adb or ssh to get the results html to your PC and open the html with any browser, it will show you the plot.

The results a0, a1, a2 tell very little information because it is just a data fit, it does not show underlying data points.

## Reply by rdjarvis · 2024-04-12 20:20:34 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

We cannot find the calibration_results.html. 

We tried find / -type f -name "calibration_results.html"

and 

locate calibration_results.html
find / -type f -name "*.html"

No luck. Any suggestions on what directory the file would be in?

## Reply by Alexander Saunders · 2024-04-12 20:49:30 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

Using the script from this post: https://forum.modalai.com/topic/2522/esc-calibration I plugged in the one calibration test we ran before trying to troubleshoot the motor issues.

![Screenshot 2024-04-12 at 4.48.29 PM.png](https://forum.modalai.com/assets/uploads/files/1712954964485-screenshot-2024-04-12-at-4.48.29-pm-resized.png)

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-12 21:00:39 UTC (in reply to Alexander Saunders)

@Alexander-Saunders , like i said the plot does not tells us anything because it does not show the original data where something went wrong. also the plot i am looking for would be something like this:

https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/doc/img/esc_calibration_mn4006_15in_6s.png

If you are not seeing the calibration xml, then you probably used older version of the voxl-esc utils, you can get latest here

https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/

and showing where the html is saved:
https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/voxl-esc-calibrate.py?ref_type=heads#L275

Do you have any data still available in the terminal where you ran the calibration, it would print the information received from the ESC (before the calibration is calculated)

## Reply by rdjarvis · 2024-04-12 21:09:50 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev We do not have the data available.

## Reply by rdjarvis · 2024-04-12 21:11:52 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev We have this:

INFO: ESC(s) detected on port: /dev/slpi-uart-2, baud rate: 250000
        ID         : 0
        Board      : version 42: ModalAi 4-in-1 ESC (M0138-1)
        UID        : 0x20333038524657120030001F
        Firmware   : version   39, hash e4f576a0
        Bootloader : version  184, hash e1c038de

        ID         : 1
        Board      : version 42: ModalAi 4-in-1 ESC (M0138-1)
        UID        : 0x20333038524657120054002A
        Firmware   : version   39, hash e4f576a0
        Bootloader : version  184, hash e1c038de

        ID         : 2
        Board      : version 42: ModalAi 4-in-1 ESC (M0138-1)
        UID        : 0x203330385246571200360037
        Firmware   : version   39, hash e4f576a0
        Bootloader : version  184, hash e1c038de

        ID         : 3
        Board      : version 42: ModalAi 4-in-1 ESC (M0138-1)
        UID        : 0x203330385246571200300020
        Firmware   : version   39, hash e4f576a0
        Bootloader : version  184, hash e1c038de

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-12 21:12:08 UTC (in reply to rdjarvis)

@rdjarvis , ok that is fine.

What params do you currently have installed on the ESC? if you can share those, i can double check them.

After i confirm the params, i suggest using a new working motor and run the calibration with limited maximum power of 40 or 50 and see what the plots look like (low enough max power to avoid burn up).

Once we verify / fix any issues, we can run the calibration to higher power.

Please get the latest voxl-esc tools on your VOXL2 from : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/dev

## Reply by rdjarvis · 2024-04-12 21:19:35 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev /old/esc_params_modalai_4_in_1_revb_mn1804_2400kv_gemfan5040.xml

## Reply by Alexander Saunders · 2024-04-12 21:23:02 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

To add to Ryan response for params, we have the value of zero for the params kp and ki.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-12 21:57:23 UTC (in reply to Alexander Saunders)

@Alexander-Saunders , OK, thanks, i don't see anything particularly wrong with using those params (even though the are from the *old* folder). I will do a test using these params and another similar motor just to check this.

I checked i only have the 1500kV version of your motor (i thought i had 2850, but cannot locate it at the moment). If i had the exact motor, i could test it. I will look again.

I just realized that the calibration script in the current state will not correctly show the total current on M0138 ESC (will show just zero). I need to make a small change to fix that. 

one test that is similar to the calibration, but will show the current is the following:

```
./voxl-esc-spin.py --id 3 --power 40 --ramp-time 2.0 --timeout 2.5 --enable-plot 1 --cmd-rate 250
```

This will spin id3 3 from 10 to 40 % power, it will take 2 seconds to ramp up the power and the test will end in 2.5 seconds and generate the plot (save to disk, same folder as the script).

40% power should be safe to start, if you can run that test with a working motor, i can take a look at the plot (html) -- you can send a screen shot of the html after you view it in your browser.

If the plot looks good, we can increase the maximum power in the ramp (gradually) and see how the motor performs. Please use the battery. If you see any abnormal behavior or unreasonably large current (in this test should definitely be less than 10A), you can terminate the test even faster using control-c.

## Reply by rdjarvis · 2024-04-12 22:36:16 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Thank you! We will test and get back to you.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-13 00:50:51 UTC (in reply to rdjarvis)

@rdjarvis I am sorry, i made a mistake, the FPV ESC (M0138) has total current sensing on ID2, so please use the following command:

```
./voxl-esc-spin.py --id 2 --power 40 --ramp-time 2.0 --timeout 2.5 --enable-plot 1 --cmd-rate 250
```
meanwhile, i will fix the calibration script to also use the total board current for the plots. The current is not used in the actual calibration procedure, but it is good for checking to make sure things look ok and there are no glitches.

Since you are using VOXL2, however, the total current will also include the VOXL2 current, which will mean the plot of current won't be as smooth.

Alex

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-13 00:59:58 UTC (in reply to Alex Kushleyev)

The change was pretty easy, i enabled the board current to be used as ESC current for the calibration plot purposes. the change is on `dev` branch of `voxl-esc` : ([commit](https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/commit/914c5462db16adeede3b03ac8809d17d5e1bdad3)) . so you can use that latest code for testing.

## Reply by rdjarvis · 2024-04-13 11:43:21 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev wonderful, thank you, as always!

We will get to this as soon as we can for testing. Looking forward to the results. 

RDJ

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-13 20:04:44 UTC (in reply to rdjarvis)

@rdjarvis, i found the correct motor 2850kV and just wanted to double check your propeller selection. 3in 3052 seems too small for this motor. Can you please confirm? Tmotor provides test data for 4in and 5in props for this motor : https://store.tmotor.com/product/f2203_5-fpv-motor.html . edit: they do also provide data for 3in (but 5 blade prop) - believe your propeller is tri-blade?

Either way is fine, just let me know and I will run the tests. I can start with the same params you did and see if i can reproduce the issue using FPV ESC. I have a 3076 propeller (tri-blade) which i can use for testing, which will be more aggressive than 3052 (i don't think i have 3052 available to test). I also have 3030.

Alex

## Reply by rdjarvis · 2024-04-13 22:49:06 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev thanks for digging up the motor.

The 3in tri-blade prop works well with this motor, for our use case. We have more aggressively pitched props as well. Please test and send those params! That would be great. This will eliminate tons of trouble shooting.

Thank you,
RDJ

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-14 19:12:43 UTC (in reply to rdjarvis)

@rdjarvis , I loaded the same params that you were testing and I was able to reproduce the issue.

The issue is that the old spin-up procedure is not working well for this particular motor and the ESC incorrectly synchronized with the motor phases (de-sync), resulting in incorrect motor control and motor overheating.

We recommend using our new sinusoidal spin-up procedure which is a lot more reliable. 

I will make a new parameter file for the Tmotor 2850kV motor with a 3076 propeller and share with you as well as resulting plots for your reference.

Alex

## Reply by rdjarvis · 2024-04-15 13:19:48 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Wonderful! Thank you for the hard work! Im happy you were able to reproduce. As you see, the motor heats up very early on the calibration cycle.

We are ready to test as soon as you can send those params!

Thank you,
RDJ

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-15 13:44:16 UTC (in reply to rdjarvis)

@rdjarvis ,

I have added the parameter file ([here](https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/dev/voxl-esc-params/misc/esc_params_tm_2203_5_2850kv_3076_3.xml)) . I used your exact motor and 3076 tri-blade propeller. 

If you have slightly different propeller, all you should have to do is just run the calibration procedure (please use `voxl-esc` tools from main branch) , update the a0,a1,a2 params and upload the new esc param file to the ESC.

I think this should perform pretty well, i did some aggressive testing (rpm step from 10k to 30k rpm), using the following command, and the results are very smooth. You can use this test and start with a lower step amplitude and make sure that works well and then increase the step size as you gain confidence. you should see smooth results like this, if you see any unusual spikes, let me know and send a plot.

```
#only test this with battery (not power supply) due to regenerative spikes
./voxl-esc-spin-step.py --id 2 --rpm 10000 --step-amplitude 20000 --timeout 3 --enable-plot 1 --cmd-rate 2000
```

![1dc58609-7890-4a4d-a5fd-de9438bdb4c3-image.png](https://forum.modalai.com/assets/uploads/files/1713188488338-1dc58609-7890-4a4d-a5fd-de9438bdb4c3-image-resized.png) 

Please upload this param file, and run the calibration, you can also do the ramp test to 100% using 

```
./voxl-esc-spin.py --id 2 --power 100 --ramp-time 2.0 --timeout 2.5 --enable-plot 1 --cmd-rate 250
```

Produces the following results on my setup (very smooth):
![9cdd2adb-0da7-426a-913e-74961c8af3b1-image.png](https://forum.modalai.com/assets/uploads/files/1713188580871-9cdd2adb-0da7-426a-913e-74961c8af3b1-image-resized.png) 

You can update your max rpm based on this result, but beware that max rpm is a function of voltage.

## Reply by rdjarvis · 2024-04-15 14:23:54 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev We will test soon and get back to you. 

As always, thank you for all the help!!

RDJ

## Reply by Alexander Saunders · 2024-04-15 17:43:46 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

We ran the calibration script and failing to see where/which directory the html file is being stored. Could you point me to the location?

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-15 18:37:12 UTC (in reply to Alexander Saunders)

@Alexander-Saunders , the file should be saved in the same directory where you are running the calibration script from (current directory). [here](https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/dev/voxl-esc-tools/voxl-esc-calibrate.py?ref_type=heads#L286) is the line of code in the calibration script, which saves the figure right before trying to plot it in a browser.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-15 18:39:02 UTC (in reply to Alex Kushleyev)

here is the calibration result i got with my setup (and the a0, a1, a2 params are already in the xml file i linked before):

![1d3b2a05-695e-4aa3-8a95-7cb3242644d9-image.png](https://forum.modalai.com/assets/uploads/files/1713206319099-1d3b2a05-695e-4aa3-8a95-7cb3242644d9-image-resized.png)

## Reply by rdjarvis · 2024-04-17 15:03:47 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev after uploading the new params you sent the ESC no longer communicates with the VOXL2. 

The ESC board is no longer recognized by VOXL2. All hardware is set up properly. 
[Screenshot 2024-04-17 110112.png](https://forum.modalai.com/assets/uploads/files/1713366104104-screenshot-2024-04-17-110112.png) 

voxl_uart_read_byte bus 12 is not initiated

Please point us in the right direction.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 15:08:30 UTC (in reply to rdjarvis)

@rdjarvis , the latest params switched baud rate from 250k to 2mbit, but that should not be an issue. You should make sure voxl esc param in px4 is 20000000.

Please try voxl-esc python tools directly and make sure px4 is disabled when you run them (instead of running the voxl-esc wrapper like you did). 

Sometimes stopping px4 gets the dsp in a weird state, in which case you can disable px4 from autostart, reboot and then do a voxl-esc-scan.py

## Reply by rdjarvis · 2024-04-17 15:09:20 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Copy all, we will try. Thank you.

## Reply by Alexander Saunders · 2024-04-17 15:19:10 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

For the esc tools, we were running the commands from /usr/share/modalai/voxl-esc-tools. To clarify, for the baud rate changes, do you want 2,000,000 or 20,000,000. We will try the tools again and confirm px4 is stopped via systemctl stop voxl-px4.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 15:20:23 UTC (in reply to Alexander Saunders)

@Alexander-Saunders, my bad too many zeros. 2,000,000 (2Mbit)

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 15:22:06 UTC (in reply to Alex Kushleyev)

The screen shot in earlier post today shows running “voxl-esc” which is a wrapper for the python tools, sometimes it is easier just to use python tools directly, but make sure they are latest version. the version in /usr/share/modalai is probably not latest. Normally you dont need to update the tools but if something is not working as expected, it is good to try the latest.

## Reply by rdjarvis · 2024-04-17 15:34:31 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev ![Screenshot 2024-04-17 113251.png](https://forum.modalai.com/assets/uploads/files/1713367994302-screenshot-2024-04-17-113251.png) 

We verified PX4 was not running.

systemctl stop voxl-px4

## Reply by Alexander Saunders · 2024-04-17 15:36:05 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

No worries. We also verified if the issue was with the particular param file and ran the command to upload a different one. No luck with that and we still receive the same error (Bus 12, ESC not detected, etc)

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 15:37:38 UTC (in reply to Alexander Saunders)

@Alexander-Saunders 

Can you please try voxl-esc tools from dev branch on github? Instead of /usr/share/modalai/voxl-esc-tools

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 15:46:16 UTC (in reply to Alex Kushleyev)

Also, which SDK are you using? i am surprised to see this issue.

Also, can you please double check the ESC bootup sequence:
- apply power
- 4 blue leds flash quickly for 1 second, then turn off
- 4 blue leds blink twice
- motor makes a quick chirp (three tones based on the latest params that provided)

## Reply by rdjarvis · 2024-04-17 15:51:39 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev ESC gave 

4 LEDs quickly flashing
4 LEDs flash 3 times
Motor chirps

## Reply by rdjarvis · 2024-04-17 15:53:46 UTC (in reply to rdjarvis)

@rdjarvis ![Screenshot 2024-04-17 115253.png](https://forum.modalai.com/assets/uploads/files/1713369193369-screenshot-2024-04-17-115253.png)

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 15:54:34 UTC (in reply to Alex Kushleyev)

One more suggestion, it often helps to use a direct connection between the ESC and your linux PC and run the voxl-esc tools there. This way you can see the plots instantly during testing and also if there are some issues with communication to the ESC, you can always connect it to the PC and check the ESC that way. 

Do you have a USB to serial adapter cable that plugs into the ESC <-> PC ?

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 15:55:34 UTC (in reply to rdjarvis)

@rdjarvis said in [Motor issues when running ESC calibration](/post/16332):
> @Alex-Kushleyev ESC gave 
> 
> 4 LEDs quickly flashing
> 4 LEDs flash 3 times
> Motor chirps

OK that is good!

## Reply by rdjarvis · 2024-04-17 15:55:56 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev, yes we have the USB/Serial connector.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 15:57:55 UTC (in reply to rdjarvis)

@rdjarvis , ok great. Lets take a step back and just make sure you can talk to the ESC from the PC.

I will test SDK 1.2.0 to make sure it works fine with voxl-esc tools with my esc.

## Reply by rdjarvis · 2024-04-17 15:58:37 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Copy all, thank you

## Reply by Alexander Saunders · 2024-04-17 15:59:47 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

Also to confirm, I followed the README from dev branch to update.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 16:02:10 UTC (in reply to Alexander Saunders)

@Alexander-Saunders , thank you for confirming. I see that you are using SDK 1.2.0, which is very recent, so it already has (almost) the latest voxl-esc tools. 

I am in the process of testing the tools on voxl2 using SDK 1.2.0, please try to connect to your PC directly and this should properly detect your ESC.

## Reply by rdjarvis · 2024-04-17 16:09:30 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 
ssh'd into Linux PC. 
Connected to ESC with USB to SERIAL
voxl2:/usr/share/modalai/voxl-esc-tools/voxl-esc-scan.py

received same error as Windows PC.

No ESCs detected

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 16:13:59 UTC (in reply to rdjarvis)

@rdjarvis,

What do you mean "ssh'd into Linux PC" ?

I am suggesting to connect the ESC to a standalone Linux PC and run the `voxl-esc-scan.py` on the linux PC (not on VOXL2).

Just wanted to clarify..

I tested the SDK 1.2.0 and the tools are working fine, it seems.

## Reply by rdjarvis · 2024-04-17 16:25:00 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

On the Linux PC we are directly connected to 4 pin JST on ESC to USB.

I ssh'd into VOXL2 from the Linux PC terminal.

I ran voxl-esc-scan.py in VOXL2 (same results) No ESCs detected.

I ran same command in Linux terminal (not ssh'd into VOXL2) same results. No ESCs detected. 

This is including running same command in /usr/share/modalai/voxl-esc-tools/.voxl-esc-scan.py

RDJ

## Reply by rdjarvis · 2024-04-17 16:28:00 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev power is on the UAV and ESC gave proper Flashes/Tones.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 16:33:57 UTC (in reply to rdjarvis)

@rdjarvis , which serial to usb cable are you using? have you tested it with an ESC before? I am wondering if the RX/TX connections are correct and not swapped.

Also, do you have any other Modalai ESC you can test just to make sure the cables are working?

## Reply by rdjarvis · 2024-04-17 16:36:54 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

MCBL-00091-1
USB to Serial UART Cable from ModalAI
Both right out of the new bag.

We have 2 of these. Tested both. Same results.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 16:50:23 UTC (in reply to rdjarvis)

@rdjarvis , ok so just to clarify.. as soon as you uploaded the new params that I provided, the esc stopped communicating? Can you please check to make sure you did not modify the baud rate in the param file before uploading?

## Reply by rdjarvis · 2024-04-17 16:58:48 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev ![Screenshot 2024-04-17 125812.png](https://forum.modalai.com/assets/uploads/files/1713373126185-screenshot-2024-04-17-125812.png)

## Reply by rdjarvis · 2024-04-17 17:06:18 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev The params you sent worked. I tested the new motors params, with the aggressive test procedures you sent.

They worked. Motors performed well and we confirmed the sinusoidal spin-up.

Binded Spektrum DSMX RX/TX and calibrated through QGC.

RC channels successfully calibrated in QGC.
Programed switches for Flight Modes.
ARM/DISARMED Motor kill all successful.

Armed for maiden flight. Slowly increased throttle with no motor response.

This led us to where we are now.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 17:27:46 UTC (in reply to rdjarvis)

@rdjarvis , thank you for clarifying. 

it seems there is some hardware issue. Can you please confirm that nothing is making contact with the ESC components, which could cause a short or something like this? Also please inspect the 4-pin UART connector on the ESC (and around it) to make sure there is no short or anything like that cause by loose debris or anything else.

## Reply by rdjarvis · 2024-04-17 19:11:50 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

We just verified all solder and JST connections on the ModalAI FPV 4n1 ESC and VOXL2.

All connections are good. No shorts, no solder balls. 4 PIN USB JST connections to and from ESC and VOXL are in perfect condition and reflect no sign of wear and tear. The first time they have been disconnected for either board was for this test.

Upon reconnecting, and power being applied all lights and tones are heard from ESC, and able to ssh into VOXL2 with no issues.

Ran esc scan and esc detect, resulting in NO ESCs DETECTED.

## Reply by Alexander Saunders · 2024-04-17 19:36:05 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

We tried a new ESC, Modalai M0138-1, and that was detected. We are replacing the hardware and will resume testing.

## Reply by rdjarvis · 2024-04-17 19:59:19 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

Top lines are from FPV ESC#2.  (GREEN ESC DETECTED)

Bottom lines are from FPV ESC#1. 

ERROR:   voxl_uart_read_bytes: Bus '12' is not initialized

This has been a common ERROR with these tests. What is "Bus 12" and how do we initialize it?![Screenshot 2024-04-17 155555.png](https://forum.modalai.com/assets/uploads/files/1713383972634-screenshot-2024-04-17-155555.png)

## Reply by rdjarvis · 2024-04-17 21:14:26 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

**UPDATE. 

#2 ModalAI FPV connected to VOXL2 and 4x T-Motor 2203.5 2850kv

Good connections, good lights and tones, VOXL2 connected to PC perfectly

Loaded params provided by you and conducted good spin test.

Connected to QGC, arm/disarm/motor kill all successful. (spins / stops)

Armed in Manual and Stabilized, motors armed and when throttle added there is no response from motors. we can view on QGC when throttle (Channel 3) is increased and get positive value. 

Verified all other channels operating in QGC Radio tab. Low, High PWM values are in limits, positive response for pitch, roll, and yaw commands. 

NO RESPONSE FROM ESC/MOTORS ON THROTTLE INPUTS. MOTORS DO RESPOND TO DIFFERENT ANGLES TO TRY AND LEVEL BUT NO THROTTLE INPUT REGISTERED WHEN USING RC.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-17 21:19:35 UTC (in reply to rdjarvis)

@rdjarvis, so when you arm, the motors are spinning at idle rpm and rpms are not changing? Can you send me a short px4 log of this test?

Did you update px4 params for voxl esc min and max rpms?

## Reply by rdjarvis · 2024-04-17 22:34:47 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev yes motors spin when armed and respond appropriately to pitch, yaw and roll inputs (motors slowing and speeding up)

We have exhausted our efforts for this evening and will re-attack in the morning. 

Thank you for all the help with hunting down these issues. We appreciate it and understand the frustration with these things. 

Thank you,
RDJ

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-18 17:30:14 UTC (in reply to rdjarvis)

@rdjarvis , based on your latest post, it seems the motors are spinning and responding to roll, pitch, yaw inputs, so i think the remaining issues may be in PX4 params.

By the way, I also wanted to mention, we have a fork of px4 flight review tool here : https://github.com/modalai/px4-flight-review . There is a quickstart guide in readme how to run this locally. Our version allows you to display ESC data such as commanded and actual RPMs, ESC temperatures, individual motor currents (where available) and total battery current.

By the way, since you are probably not using an APM for voltage/current monitoring, you should set (or double check) the `voxl_esc` px4 driver to publish the voltage/current measurement, using `VOXL_ESC_PUB_BST` set to `1` .Then you will see the battery voltage and total current in battery status. (however if you are using APM, then you dont need that, set to 0)

Alex

## Reply by rdjarvis · 2024-04-18 18:03:45 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev We are using the supplied PM from ModalAI C11 dev kit.

Tested this morning. All VOXL2 systems good. 

Arm/Disarmed-Good
Arm/Motor Kill-Good

Arm/Manual-Throttle Increase on RC Controller, UAV motors do not respond proportional to RC inputs. When throttle is increases, motors perform a very slow increase in RPM that does achieve flight. RPMs stay very low. 

Could you point us to the PX4 params that we should be looking at to verify proper configuration?

![Screenshot 2024-04-18 134704.png](https://forum.modalai.com/assets/uploads/files/1713463385372-screenshot-2024-04-18-134704.png)

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-19 02:45:22 UTC (in reply to rdjarvis)

@rdjarvis , besides the PID tuning params, you need to make sure the min and max rpms in PX4 match what you have in esc params: `VOXL_ESC_RPM_MIN` and `VOXL_ESC_RPM_MAX`. did you set these PX4 params to 4000 and 40000? (btw in your test, was the motor able to reach 40K rpm? with my more aggressive prop, i think i had about 35K max). 

It is not a big deal if your ESC param in the ESC itself has maximum rpm that is higher than the motor can achieve. The ESC will just try to apply 100% power and will reach whatever rpm the motor can run at 100% power. But in PX4 params, you need to make sure that you set the maximum rpm that is actually achievable, otherwise PX4 will request the rpm that ESC cannot achieve and the drone will be less stable at maximum thrust.

## Reply by rdjarvis · 2024-04-19 10:15:29 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

Yes, we confirmed the Params in PX4 QGC are identical to the Params in VOXL. Yes, Max RPM when performing calibration tests was 42k. I set it at 40k in both PX4 and VOXL-esc-params. 

No response from throttle input when armed. We recalibrated the Radio and ensured RC Channel 3 was responding to Tx input.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-19 12:38:53 UTC (in reply to rdjarvis)

@rdjarvis , have you tried using actuator test to spin the motors (obviously be careful if props are on, or remove the props for the test). The actuator test should allow you to test the motors in the full range that you specified

## Reply by rdjarvis · 2024-04-19 13:15:46 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Good morning.

Yes, Actuator tab in Vehicle Setup in QGC has VOXL ESC selected, motor directions are correct, and motor slider controls the motors.

Ch 3 RC Throttle Tx input does not apply actual throttle inputs when UAV is armed in any flight mode.

RC calibration was successful and RC Ch3 reacts correctly when Spektrum Tx mode 2 throttle stick is manipulated.

 I will get you a log this morning when I'm clear of my meetings.

As always, thank you,
RDJ

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-19 14:22:43 UTC (in reply to rdjarvis)

@rdjarvis, yes lets get a log where you are in manual flight mode (thrust, roll, pitch, yaw control) and you arm the drone and just move the thrust stick up and down a few times trying to take off. As a separate test, at idle throttle try to move roll and pitch stick to see the response from those inputs.

It looks like a px4 configuration issue but i am not sure what exactly.

## Reply by rdjarvis · 2024-04-19 14:23:50 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Awesome, will do.

Thank you,
RDJ

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-19 14:32:18 UTC (in reply to rdjarvis)

@rdjarvis,

Also please check the value you use for the following param THR_MDL_FAC. Just curious about the current value, it should be close to one (0.7-0.8) for rpm control, but i can help you compute it exact value.

https://discuss.px4.io/t/thrust-curve-compensation-through-thr-mdl-fac/13207/3

## Reply by rdjarvis · 2024-04-19 15:01:35 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev How do I upload a log? The forum say I do not have permission.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-19 15:04:47 UTC (in reply to rdjarvis)

@rdjarvis 

Upload it here and you can view results too. https://review.px4.io/ . The official flight review does not plot our custom esc data, but i will let you know how to view it later. I can download the log from the link above after you upload it and share a link

## Reply by rdjarvis · 2024-04-19 15:10:21 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev [mavlink] Event dropped (78, 65529)

## Reply by rdjarvis · 2024-04-19 15:11:53 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev https://review.px4.io/plot_app?log=ae01b6f0-7910-43e4-a1c2-0d36ecc909d1

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-19 15:51:43 UTC (in reply to rdjarvis)

@rdjarvis said in [Motor issues when running ESC calibration](/post/16425):
> https://review.px4.io/plot_app?log=ae01b6f0-7910-43e4-a1c2-0d36ecc909d1

It seems you have something wrong with the thrust control (some filter?) the motors respond fine to roll / pitch  but not thrust. see plots below showing RPMs. The ESC is tracking the desired RPMs well (actually a bit higher than desired at high rpm, but that is ok for now)

![ed5ca03f-84de-47c8-aa0c-6c0783febed2-image.png](https://forum.modalai.com/assets/uploads/files/1713541802254-ed5ca03f-84de-47c8-aa0c-6c0783febed2-image.png) 

![1ef15a4a-964e-4764-b915-6ca7fe402f74-image.png](https://forum.modalai.com/assets/uploads/files/1713541823341-1ef15a4a-964e-4764-b915-6ca7fe402f74-image.png)

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-19 15:52:49 UTC (in reply to Alex Kushleyev)

(look at how desired motor outputs and desired rpms rise very slowly when you increase the desired thrust, never reaching enough rpms to hover)

## Reply by rdjarvis · 2024-04-19 16:03:40 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Thank you. We understand that the desired inputs and actual input are not the same. 

We have no filters. All ModalAI Hardware and Software are being used. ModalAI PX4 QGC Skin is used. Spektrum Rx/Tx DSMX as suggested by ModalAI is used. 

We have purchased 2 ModalAI FPV 4n1 ESC and multiple VOXL and VOXL2 Dev kits to keep all hardware in the same ecosystem for easy integration and R&D for our product. 

There is a disconnect between the FC/ESC comms on throttle Ch 3.

## Reply by rdjarvis · 2024-04-19 16:30:48 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

I do appreciate your willingness to help. I have selected ModalAI products for our organization based off of current and future capabilities. I have even selected a motor that I know you are using to ensure stable testing and flight characteristics. 

If the ModalAI DEV team cannot troubleshoot issues on known UAV setups that you have at your shop, then I need to have a conversation with a different department.

All web advertising, Documentation, and Videos produced by ModalAI have shown these capabilities working flawlessly and it feels we have been oversold the true capabilities of the system today. 

At this point these products cant even take flight.

## Reply by rdjarvis · 2024-04-19 19:03:20 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

I swapped the RC Channels for testing. 

Throttle and yaw were swapped RC3 and RC4.

Same results with throttle not responding to inputs on RC4, instead of RC3.

## Reply by rdjarvis · 2024-04-19 19:10:14 UTC (in reply to rdjarvis)

https://review.px4.io/plot_app?log=87904892-aff8-4093-80a9-89cb5e28ed22

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-19 20:47:38 UTC (in reply to rdjarvis)

@rdjarvis ,

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.
![87347e5d-2624-4d68-bf08-87b8a263a23c-image.png](https://forum.modalai.com/assets/uploads/files/1713559423823-87347e5d-2624-4d68-bf08-87b8a263a23c-image.png) 

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

## Reply by rdjarvis · 2024-04-19 21:57:46 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

Thanks Alex, SYS_VEHICLE_RESP parameter is -0.40. With small incremental adjustments there was no change in UAV behavior. Changed the value to 0.40 with no change in behavior. 

RDJ

## Reply by rdjarvis · 2024-04-22 15:08:55 UTC (in reply to Alex Kushleyev)

@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

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-22 15:42:28 UTC (in reply to rdjarvis)

@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.

## Reply by rdjarvis · 2024-04-22 16:11:14 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev I am going to upload FPV_REVB. unless you recommend another.

RDJ

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-22 16:21:05 UTC (in reply to rdjarvis)

@rdjarvis , yes but change the vbatt since fpv revb is 6s. That is probably closest to your config

## Reply by rdjarvis · 2024-04-22 16:21:21 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

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?

## Reply by rdjarvis · 2024-04-22 16:23:08 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

Also, sinusodial value is 0 in FBV_RevB, I will change this to 1.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-22 16:23:09 UTC (in reply to rdjarvis)

@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).

## Reply by rdjarvis · 2024-04-22 16:23:50 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

copy all, will do.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-22 16:25:45 UTC (in reply to rdjarvis)

@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.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-22 16:27:04 UTC (in reply to Alex Kushleyev)

you can find our FPV params here :

https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-px4-params/-/blob/master/params/v1.14/platforms/FPV_RevB.params

## Reply by rdjarvis · 2024-04-22 18:14:44 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

We kept the custom ESC config for the 2203.5, and uploaded px4 FPV_RevB_v4.

Motors are more responsive in all channels, Throttle channel still conducts a "ramp up", but more aggresively when RC Tx input is applied.

## Reply by rdjarvis · 2024-04-22 18:42:51 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev No actionable response from throttle.

## Reply by rdjarvis · 2024-04-22 19:00:15 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

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.

## Reply by rdjarvis · 2024-04-22 19:23:24 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 

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.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-22 19:30:40 UTC (in reply to rdjarvis)

@rdjarvis , interesting. Can you please share a px4 log from that position mode test?

## Reply by rdjarvis · 2024-04-22 19:40:16 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev 
https://review.px4.io/plot_app?log=f154b563-aa6e-4ff8-b603-67b9b6e2e64c

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-22 19:51:02 UTC (in reply to rdjarvis)

@rdjarvis , yes in this mode, the vehicle seems to be responding to thrust commands and motors are tracking rpm well (even though without props)

![c7f8c2c5-85b1-429d-9df6-d60bdfaf19a5-image.png](https://forum.modalai.com/assets/uploads/files/1713815354687-c7f8c2c5-85b1-429d-9df6-d60bdfaf19a5-image.png)

## Reply by rdjarvis · 2024-04-22 20:02:17 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev I agree, what do you think the next troubleshooting step is for this issue?

## Reply by Alex Kushleyev (ModalAI staff) · 2024-04-22 20:29:23 UTC (in reply to rdjarvis)

@rdjarvis ,

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?

## Reply by rdjarvis · 2024-04-24 13:17:35 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Thanks Alex, We will test it out. In the meantime my team will be sending the first FPV 4n1 ESC back, so you can investigate onsite.

Thank you,
RDJ

## Reply by Alex Kushleyev (ModalAI staff) · 2024-05-08 16:24:07 UTC (in reply to rdjarvis)

@rdjarvis , please let me know the RMA number once you send back the M0138 ESC. Thanks!

## Reply by Alex Kushleyev (ModalAI staff) · 2024-06-27 21:35:35 UTC (in reply to Alex Kushleyev)

@rdjarvis , I received the M0138 ESC that you sent back (reported that you were unable to communicate with the ESC).

The issue was that the baud rate in ESC params was set to 2.5Mbit instead of 250K by accident, so our auto-scan in ESC tools could not detect the ESC (and VOXL2 DSP does not support 2.5Mbit).

We will fix this in future ESC firmware to prevent accidental setting of unsupported baud rates. Sorry about that.

Alex