Yes! this is the second followed flight. After the Gyro & Accel error, I checked everything especially the power wires. I did not find anything, everything looked good so I first put a hover flight for 10 minutes and then flown in the Auto mode where I got the GPS glitch error.
Is it possible that Pixhawk 6C not supplying the enough power to the GPS & Receiver? Maybe there is some voltage drop from the 6C side because I had a issue of low receiver voltage too. Should I supply the separate power to receiver and GNSS?
Youâre probably onto something with the low power message. Figure out whatâs drawing too much power and use a different wiring path for that component. Itâs not really worth troubleshooting anything else until thatâs sorted (and itâs probably the root cause).
@scientist_bala I am not sure if i can give the right inputs, others as @Yuri_Rage are experts.
But how is your HW setup. So which part is powered from which source and which connection.
Is thelow power reading of your receiver just a direct function of the receiver and directly transmited to the transmitter or is it a reading which is on any kind handled by the Pixhawk?
Above you had a disccusion about using two GPS rceivers you are using as movong base. Is this still the case?
Also yuri figured out that you had a problem with your battery setup before, is this 100% solved? What was the reason and what did you changed.
I am not able to open / read your logfile: Following message popsup âLog Browse will not functiion correctly without FMT messages in your log. These appear to be missing from your logâ
Maybe your SD-card is damaged or the Pixhawk makes also write errors due to power problems?
Thanks for the reply @Yuri_Rage
I checked all the power wiring and not able to see what could be faulty. My question is, if there was a power issue then how come the pixhawk was still powered? The receiver and GNSS were powered from the pixhawk.
In both the cases (the receiver voltage low and GPS glitch), the drone was landed in a failsafe mode and it was connected to the Mission planner where I can see the parameters. Means, the pixhawk 6C was powered all the time otherwise drone would have shut down and fallen from the sky.
It would explain sensor glitches and SD card corruption quite easily. There may have been just enough current to keep the critical memory and CPU functions going but not enough to function properly. Thatâs my theory at present.
Just because the wiring âlooks goodâ doesnât mean youâre powering all components on circuits that can handle them. GPS modules are notoriously power hungry and may need power from something other than the autopilotâs own voltage regulator, especially if other peripherals are competing for power on that circuit.
Thanks for the reply @Juergen-Fahlbusch Sir.
Your inputs are totally amazing and each single input matters.
The battery is connected to the Mauch sensor and all the ESCs. Mauch powers the Pixhawk 6C and the receiver & GNSS are powered and connected to Pixhawk 6c.
Yes! a direct function
Yes! I am using a moving base configuration for Yaw estimation (GNSS is based on UM982)
No! I am still figuring it out. I have been flying this drone for few days and had a 7-8 successful flight before this issue started.
I will change the SD card, donât know about pixhawk making error due to power problems.
Thanks again for the reply @Yuri_Rage
This is insightful.
Thanks! It makes sense, The mauch sensor connects in series to the load and maybe due to the ESCs load fluctuation something is happening because both the issues came in high wind environment.
Okay! understood. But I have always used GNSS powered by the FC and never had any issue. The only problem is supplying the power from other source is finding a reliable BEC module.
One more thing, How good is Holybro PM02 V3, rated continuous current is 60A. My continuous current is around 50A, how good are their power module? I did not trust the data thatâs why I am using mauch sensor (100A) for powering and current sensing.
@scientist_bala , I have no experience with ardupilot and FC-boards so on this point it is good to follow Yuriâs recommandations. But on standard RC-electronics i have some experience over decades. I have learnt, if the receiver shows a power problem than there is a (serious) power problem. All what yuri stated I can agree. Also if the connection seems to be ok it is not always so. It could be some not so good soldering or crimping. Also the cable size, length and size, can have drammatical influence if all power is routed throught the same wire. If I have high loads like motors i always try to keep the power wires as long as possible from the powerlines of the electronic. So i place the seperate BEC for the electronic as near to the battery connector as possible.
And also it is question of the real health of the battery itself. Is it a new one or is it used for many flights.
So from all this I believe you have first a power problem and all other are follow up problems
For the last few days I have done the thorough checking to find the fault. Here is my observation:
There is no power loss, actually the receiver works on the 5V but when I checked the receiver end voltage (powered by 6C) it is coming around 4.5V to 4.7V, so due to that the low voltage warning comes in the transmitter.
I checked the voltage at GPS end, it shows the 4.9V and as per the manufacturer datasheet it can operate from 3.6v to 6v voltage (1.2W) so I donât think that there is any problem in power supply.
There is no problem in mauch, it supplies the proper power to Pixhawk 6C but I think 6C only drops the output voltage due to load. I connected the same setup with cube orange and found out the receiver end voltage is coming 4.9V+
Now I seriously do not know what could be the reason of GPS glitch, I am guessing the problem with my Pixhawk 6C because last to last flight (flight before crash) I noticed the warning of BAD Gyro Health & BAD Accel Health for few seconds during flight and I guessed because of this it switched to RTL and landed (I earlier thought that it happened due to the receiver voltage low).
Now the 6C shows the âArm Need Alt Estimatesâ even in the Althold mode and I am not able to arm it. (Does it point to the Barometer issue?)
And how do you guys do the ground test? I tried by switch the props (Clockwise props to anticlockwise motors and vice versa) so that drone will not generate the thrust and I can simply run the current load test. What mode do you guys try for ground test? I tried in Stabilize mode and noticed after some time the 2 motors starts running faster and 2 starts running slower and resulted in one ESC fused after running it at almost 90%+ throttle for 6 minutes (I checked the ground was level, even done the level calibration test before testing to make sure there is no roll or pitch tilt)
I really want to your opinion in few more things: Do I need to shield my GPS to Pixhawk connection wire and the pixhawk power wire (coming from mauch, this wire is coming with the same path of ESC power wires)?
Really looking forward to your opinions and thank you so much for your guidance.
4.5V on an otherwise idle 5V circuit sounds concerning. I stand by my premise that you are overstressing the autopilotâs voltage regulator and should power some of your peripherals more directly from the BEC.
Hello @scientist_bala I am also with @Yuri_Rage that all this donâ show that you donât have a power problem.
How you measured the voltage on the receiver and the gps. Was it a single measurement or did you monitor it over your full test run. The most probably problem you have are some short power failure which will result in switch to failsafe or glitches.
I donât know how much power your pixhawk can deliver to other devices.
Your testrun with the props running in wrong direction is a possibility to test the ESCs and Motors under load. but it is not thrust less. It has a full down thrust and is pressing your drone on the workbench. If it is now running in stabilize mode the controller tries to do this. Your drone will be not 100% leveled on the bench so the controller tries to press on one side more and on the other side less. But the drone is not following this commands as it is stable pressed to ground. Therefore the controller is commanding more power and that results in your observation. That the ESC will be fused after 6min full load shows that it is not the best solution. I always use in my usecases ESC which can permanently deliver more power than the max motor power.
Shielding of the gps dataline is not wrong but normally not necessary. The signal on this line is digital signal line with relative high power and not a small analog signal. So the glitches are most probably not by signal distortion on this line.
I recommend to power all external device with an own BEC which can minimum deliver 150% of the sum maximum powerconsuption of all connected devices. Make your testruns and monitor permanently the voltage of the pixhawk. Best is if you can monitor the 5V as well as the internal 3.xV
Likely backwards thinking. The GPS module is almost certainly the most power hungry component on your board unless youâre using a very powerful telemetry radio.
Through the voltmeter, I removed the small wire insulation of red and black wire at the receiver end and checked the voltage using voltmeter. Yes! I monitored the voltage during the full test, It was fluctuating between 4.5 to 4.7v
No It does create a thrust at all, as motor and prop direction is opposite. It will push the drone down if I flip the propellers.
Actually both ESC and motor are gone, first motor gone and I guess then ESC. Yeah! you are right, I currently have these with me and will change it in future.
Yes! currently I am only connecting two things to the pixhawk: receiver and GPS, I will power the receiver from the BEC as it is consuming more power. Then only GPS will be powered from the pixhawk and I guess there will not be any issue.
How do you perform ground test? same way or different?
Hello @scientist_bala I am sorry that you lose one motor and one ESC by your groundtest. It might be happened while you run the props in the opposite direction. If you turn the props in the wrong direction they will have more air resitance and a bad efficiency. So the motors needs more power to run the props on the desired speed. Are you using brushless motors and is the ESC controlling the speed (rpm) or the power? It might be better for your test also to flip the props if you mount it to the motors turning in the other direction.
I am using no multicopters only normal planes and traditionall helis. On a traditional heli i can run easy ground test without blades or with blades on adjusted to really no thrust or small down thrust.
Monitoring the voltage with a voltmeter shows you the voltage filtered by a very low pass filter. This filter is built in the voltmeter. So if this readout is tooglng between 4.5V and 4.7V on a normally stabelized 5V output it mean that the stabilization is at are little bit beyond the limit. You canât see small drops below 4.5V for some milliseconds with this setup. I am not knowing if this can be read out the pixhawk logfile as I am still not really started using ardupilot.
But if the 5V regulator is at the limit than also this can have influence to the 3.3V regulators of the flight controller and the GPS controllers. If it is only a vey short voltage drop it will end in wrong readings of analogue values like accelometer, gyro, compass, gps-signal. If it is a longer drop it end up with a power reset of the controllers.
So best possible power distribution is on of the first rules in any electronic based project.
Thanks again @Yuri_Rage, Yes my telemetry radio is powerful long range one and I guess it sucks the more power in my setup.
My GNSS rating is 1.6W and nothing else will be connected to pixhawk except the GNSS for powering, Do you still think that I should power the GNSS via BEC? I have checked the wiki and it says that pixhawk can provide power output of 5v 1.5A, which is good.
The only reason I donât want to connect the external BEC to GNSS because I donât know how reliable will be the BEC for long-term which I have. This is what I have:
How do you generally setup your GNSS system? Do you also power everything separately? and does GNSS receiver have interference with the Radio telemetry or other electronics? Thanks again.
Yes! Exactly. I will make sure that no motors runs more than 60%, I will try the props flipping setup also.
You can only see the Pixhawk input voltage drop in the logs, it does not show the pixhawk output voltages.
This makes totally sense, maybe that is the reason that during one flight it shows the âGyro and Accel Bad Healthâ and another flight the GPS glitch. I really want to know @Yuri_Rage opinion on this. Thanks!
Yeah! totally understood. I have attached the above 5V 3A bec photo which I have, what do you think about it? is that BEC reliable for long term use and input voltage fluctuations? If this fails during the flight then it might end up in a crash.
I have read somewhere that GNSS can have interference with the Radio Telemetry systems what do you say on that? I am using UM982 based GNSS (Dual Antenna configuration for Yaw estimation) my GNSS and radio is close to each other (due to spacing problem).
Hello @scientist_bala the GNSS signals can be disturbed by lots of reasons. The main problem is that thi signals are send out from the sattelites with rally low power and than they have to pass through a long way of our cloudy and dirty athmosphere. Than the signals are maybe also reflectet on some more or less close obstacles. And at last we are using cheap hobby receivers.
Yes, the GNSS signals can have also interferences with any kind of other electronic specially any kind of nearby radio transmitters if these device send in the same frequency band as the GNSS signals. I donât know which frequency you are using with your telemetrie system but most of these things are working in the ISM-Bands and these bands are seperated from the GNSS frequency bands.
But I am still in the opinion that this is not the reason fore your glitches. Which GPS receiver are you using? For example the Holybro UM982 based receiver need a input voltage of 4.75V to 5.25V. So small drops below 4.75 can produce glitches. But also your settings can cause glitches. If you are using all possible GNSS systems and you allow your receiver to select the best signal than your receiver can switch from one system to another and this switch over will produce a glitch as the different systems are not synchronized to each other.
I can say anything to your BEC as I donât now this special module by if it is providing upto 15W than this might be not a problem only for GPS and RC-receiver
Stable high voltage is a must for proper GNSS receiver operation. So improve that first, other people do not have this problem probably because they have better power supplies and cabling.
