# Sentinel flips during takeoff Source: https://forum.modalai.com/topic/2197/sentinel-flips-during-takeoff Category: Development Drones (https://forum.modalai.com/category/44/development-drones) Tags: sentinel Posted: 2023-05-26 16:25:58 UTC by stevedan Replies: 37 · Views: 10905 ## stevedan · 2023-05-26 16:25:58 UTC We just got the Sentinel test and have been doing some tests with it. We noticed a random behavior that when we takeoff using the takeoff mode from the px4 in QGroundControl, the drone flips sometimes. The weird thing is that it does it randomly. Sometimes it flies and sometimes it flips because one of the motor is not spinning fast enough. We observed this behavior in two different drones. The images below shows the images of the plot of the actuator output sent to the drones motors after doing two different tests. The first one was successful(image on the right) and the following was the one the issue occurred(image on the left). ![Screenshot from 2023-05-26 18-16-21.png](https://forum.modalai.com/assets/uploads/files/1685118150976-screenshot-from-2023-05-26-18-16-21.png) What is strange is that px4 sends strange revolucion value to the drone. Is there any cause of this? The data collected from Qgroundcontrol is the one below. https://drive.google.com/drive/folders/1tFS2fI25ayHK0pZ4bpmeG1JC0PZRACEX?usp=sharing ## Reply by Eric Katzfey (ModalAI staff) · 2023-05-26 18:37:24 UTC @stevedan A couple of questions. First, are you power cycling the drone in between each of these flight attempts or just landing and then attempting the next flight without a power cycle? Is it always the same motor that appears to not be turning? If so, is it the same motor on the second drone? ## Reply by Eric Katzfey (ModalAI staff) · 2023-05-26 18:39:24 UTC @stevedan Also, with battery / power removed, can you slowly rotate each motor by hand and see if you can feel any sticky spots? Any unusual noise from the motor when it is being powered? ## Reply by Eric Katzfey (ModalAI staff) · 2023-05-26 21:09:21 UTC @stevedan Couple more questions. Are you setting the altitude for the mission to be 0.51m? That's pretty low. It could be trying to turn towards the first waypoint before it has even left the ground. Can you try at a higher altitude? What are you using for position control. Doesn't look like you are using GPS. ## Reply by Eric Katzfey (ModalAI staff) · 2023-05-26 21:46:33 UTC @stevedan And if you set the parameter UART_ESC_VLOG to 1 then we can see in the logs if the ESC is doing the right thing. ## Reply by stevedan · 2023-05-27 15:47:18 UTC (in reply to Eric Katzfey) @Eric-Katzfey i am not power cycling th drone. I do the flight immediately. Also, when this happens, it happens in the same motors. ## Reply by stevedan · 2023-05-27 15:49:39 UTC (in reply to Eric Katzfey) @Eric-Katzfey yes, it happens on a different motor on the second drone but when it happens on eahc drone, it happens in the same motors ## Reply by stevedan · 2023-05-27 15:51:42 UTC (in reply to Eric Katzfey) @Eric-Katzfey i am flying indoor. Going high is a bit dangerous. I have done this multiple times on the rb5 without issue. ## Reply by stevedan · 2023-05-27 15:53:48 UTC (in reply to Eric Katzfey) @Eric-Katzfey i will log it on Monday and send it. ## Reply by Eric Katzfey (ModalAI staff) · 2023-05-27 18:34:39 UTC (in reply to stevedan) @stevedan A video of a good flight and of a bad one would also be pretty helpful. ## Reply by stevedan · 2023-05-29 10:19:32 UTC (in reply to Eric Katzfey) @Eric-Katzfey when I spin the motor slow, it does as shown in the video but spinning it a bit fast, it goes smoothly. No unusual noise when I turn the drone up. Videos are in the same link as before. https://drive.google.com/drive/folders/1tFS2fI25ayHK0pZ4bpmeG1JC0PZRACEX?usp=sharing ## Reply by stevedan · 2023-05-29 11:08:01 UTC (in reply to Eric Katzfey) @Eric-Katzfey I have also added a video to the link and the log file with the name test_flight_UART_ESC_VLOG_fail for the failed flight test and test_flight_UART_ESC_VLOG_sucess for the successful flight test. ## Reply by Eric Katzfey (ModalAI staff) · 2023-05-29 17:11:12 UTC (in reply to stevedan) @stevedan Thanks! It's clear from the logs that PX4 is commanding the proper motor speed to the ESC but the ESC is reporting that the motor is spinning much slower than the desired speed until the drone starts to take off. At that point that motor is commanded to go to maximum rpm and then all of a sudden the motor does start spinning at the desired speed. We are discussing this internally and will come up with a recommendation for next steps. ## Reply by Eric Katzfey (ModalAI staff) · 2023-05-29 17:51:31 UTC (in reply to stevedan) @stevedan One quick thing you can try is to blow some compressed air through the motor. If there is some debris stuck inside the motor then the air could blow it out. ## Reply by stevedan · 2023-05-30 10:02:26 UTC (in reply to Eric Katzfey) @Eric-Katzfey I have tried that and it seems not to work. As you said, this happens when during the arming, one of the propellers does not spin fast enough like the others. It happens randomly on both drones. ## Reply by Eric Katzfey (ModalAI staff) · 2023-05-30 16:45:47 UTC (in reply to stevedan) @stevedan Okay, thanks for trying that. We are still discussing internally on best next steps. ## Reply by stevedan · 2023-06-01 13:10:54 UTC @Eric-Katzfey Just adding more information, this also happens sometimes in manual flight, but it take time for the motors to get to speed during arming. ## Reply by Eric Katzfey (ModalAI staff) · 2023-06-01 14:24:21 UTC (in reply to stevedan) @stevedan Okay, thanks! And thanks for your patience. We are locating a drone here in San Diego that exhibits the same behavior so we have a way to reproduce and resolve the issue. One option is to send some new motors but our lead ESC engineer believes he can resolve this with an update to the ESC firmware. ## Reply by stevedan · 2023-06-02 09:02:23 UTC (in reply to Eric Katzfey) @Eric-Katzfey Thank you for the fast response. Let us know because there is a bit of urgency to use the drone and there wont be enough time to procure another due to lead time. We currently have 3 new drone and plan to procure more but this is hindering us from doing so. ## Reply by Eric Katzfey (ModalAI staff) · 2023-06-03 16:08:58 UTC (in reply to stevedan) @stevedan Okay, understood. We are testing some new ESC firmware now and hope to have an update for you early next week. ## Reply by Eric Katzfey (ModalAI staff) · 2023-06-06 23:57:38 UTC (in reply to stevedan) @stevedan We will need to walk you through the procedure to update the ESC firmware. In order to do that we need to know what software you have running on the drone now. Can you paste the output of `voxl-version`? ## Reply by stevedan · 2023-06-07 09:09:05 UTC @Eric-Katzfey ``` Service Name | Version | Enabled | Running | CPU Usage --------------------------------------------------------------------------- docker-autorun | 1.2.4 | Disabled | Not Running | docker-daemon | 1.2.4 | Disabled | Not Running | modallink-relink | 0.16.1 | Disabled | Not Running | voxl-camera-server | 1.3.5 | Enabled | Running | 116.7 voxl-cpu-monitor | 0.3.0 | Enabled | Running | 0.0 voxl-dfs-server | 0.1.0 | Disabled | Not Running | voxl-imu-server | 0.5.0 | Enabled | Running | 0.0 voxl-mavlink-server | 0.3.0 | Enabled | Running | 0.0 voxl-modem | 0.16.1 | Disabled | Not Running | voxl-portal | 0.5.0 | Enabled | Running | 5.6 voxl-px4-imu-server | 0.1.2 | Disabled | Not Running | voxl-px4 | 1.12.31 | Enabled | Running | 0.0 voxl-qvio-server | 0.8.2 | Enabled | Running | 27.8 voxl-remote-id | 0.0.5 | Disabled | Not Running | voxl-softap | 0.1.5 | Disabled | Not Running | voxl-static-ip | 0.1.5 | Disabled | Not Running | voxl-streamer | 0.4.1 | Enabled | Running | 0.0 voxl-tag-detector | 0.0.4 | Disabled | Not Running | voxl-tflite-server | 0.3.1 | Disabled | Not Running | voxl-time-sync | 1.2.2 | Disabled | Not Running | voxl-vision-px4 | 1.4.0 | Enabled | Running | 5.6 voxl-wait-for-fs | 1.2.2 | Enabled | Completed | ``` ## Reply by stevedan · 2023-06-07 09:51:37 UTC (in reply to Eric Katzfey) @Eric-Katzfey Is it possible we can set a time that both of us are available to speed up the process given that your timezone is different from mine?. like 6pm spain time? ## Reply by Eric Katzfey (ModalAI staff) · 2023-06-07 22:42:58 UTC (in reply to stevedan) @stevedan Would you be willing to just move to our latest software platform release to resolve this rather than trying to get new ESC firmware setup in the release that you have now? It is in beta but we can give you access to it and it should solve your flipping issue. ## Reply by Eric Katzfey (ModalAI staff) · 2023-06-08 00:16:27 UTC (in reply to stevedan) @stevedan I sent you a link to the new platform release in email if you are interested in trying it out. ## Reply by stevedan · 2023-06-08 08:24:05 UTC (in reply to Eric Katzfey) @Eric-Katzfey I can test this release and see if it solves the problem. When would this release be officially out?. ## Reply by Eric Katzfey (ModalAI staff) · 2023-06-08 15:16:44 UTC (in reply to stevedan) @stevedan I depends on what kind of issues we find with it as we continue testing it. We're hopeful that it will be ready for official release in the next week. ## Reply by stevedan · 2023-06-08 15:35:19 UTC (in reply to Eric Katzfey) @Eric-Katzfey Maybe you can help me fixed but the vio result on Qgroundcontrol is streaming at 1hz, and the reaction speed of the remote control on Qgroundcontrol is really bad. It reacts slow, is there something I am doing wrong ![da55f918-135a-4636-a2b4-8bfb0f634445-image.png](https://forum.modalai.com/assets/uploads/files/1686238517899-da55f918-135a-4636-a2b4-8bfb0f634445-image.png) What is strange is that from the drone, the vio data ms is fine voxl2:~$ voxl-inspect-qvio waiting for server dt(ms) | T_imu_wrt_vio (m) |Roll Pitch Yaw (deg)|features|quality| state| error_codes | 29.3 | -0.00 -0.00 -0.00| -0.0 0.0 0.0| 28 | 27% | OKAY | ^C ## Reply by stevedan · 2023-06-08 16:18:58 UTC (in reply to stevedan) @Eric-Katzfey This is a video of what I mean-> https://drive.google.com/drive/folders/122cPZ1S3Z_gP0yo8nipRGJHqpJTSj9c3?usp=sharing ## Reply by Eric Katzfey (ModalAI staff) · 2023-06-08 17:20:42 UTC (in reply to stevedan) @stevedan Sorry, but could you start a new forum thread for this new issue? ## Reply by Eric Katzfey (ModalAI staff) · 2023-06-09 16:17:38 UTC (in reply to stevedan) @stevedan Can you tell if the new software release fixed the motor not spinning issue or do you need to resolve the new issue before you can test? ## Reply by stevedan · 2023-06-10 13:47:57 UTC (in reply to Eric Katzfey) @Eric-Katzfey i would love to solve that issue first but it seems that the fact that the telemetry is low was done intentionally. I will stress test the drone on Tuesday when i go back to the office and give feedback. Although with the new code during arming the motors spins way smoother compared to before and doesn't do what happens before. I will stress test and let you know. ## Reply by stevedan · 2023-06-14 16:54:04 UTC (in reply to Eric Katzfey) @Eric-Katzfey Does this version work with mavros, is there any specific detting to enable the ise of mavros? ## Reply by Eric Katzfey (ModalAI staff) · 2023-06-14 17:10:34 UTC (in reply to stevedan) @stevedan Happy to hear that the new software fixed the motor issue! As for the new question, can you please open that up as a new forum topic? Thanks! ## Reply by stevedan · 2023-06-15 15:58:30 UTC (in reply to Eric Katzfey) @Eric-Katzfey For now, it seems that the problem is solved because during arming the drone spins faster and smother, if anything occur I will let you know. Thanks for the support. ## Reply by Eric Katzfey (ModalAI staff) · 2023-06-15 16:02:06 UTC (in reply to stevedan) @stevedan Excellent, thanks for letting us know! ## Reply by stevedan · 2023-07-06 12:35:01 UTC (in reply to Eric Katzfey) @Eric-Katzfey I am having issue with the new image, it seems like when I am running a docker and I reset for exampe a ros node inside the docker, after doing it 2 times, the whole ubuntu shuts down. In order to acces it I have to unplug and plug the drone to the batteries and then it works. Do you know what could possible be the problem to this. I monitored the dockers stats and the cpu usage is 80% of one core and the memory usage is like 1.16%, which is not that high. This only happens on the sentinel. ## Reply by Eric Katzfey (ModalAI staff) · 2023-07-06 15:31:28 UTC (in reply to stevedan) @stevedan No, we have not encountered that. But can you open this up in a new thread so that it has an appropriate title? Thanks!