Posted by Drone newbie on August 12, 2015 at 3:50am
Dear all,As i am a newbie in the quadcopter world, i did my first flight ever yesterday, which resulted in two fried motors. After my research, i decided to buy the following parts for my first quadcopter. Those areDJI F450 frame with its extension legsDJI E310 tuned propulsion kit ( 2312 motor, 420S ESC, 9450 props)APM 2.6 flight controller with gps moduleMultistar 10000mah 4S 10C batteryTURNIGY 9XR radio with FRsky DJT transmitter and V8FRii receiverThe quadcopter should be in the 1,5-2kg range of takeoff weight.So, I tried to do my first ever flights by slowly hovering over the ground for 10-15 seconds in order to see how the quadcopter responds. I had a couple of turnover to the side of the quadcopter during landing but without damages as the speeds were slow. However, in my last effort, the quadcopter landed and felt to the side with the 2 props attaching to ground. All The props didnt stop spinning and after 3-4 seconds i saw smokes coming out of 2 motors. In my panic i turned off the radio but it kept spinning a little faster and then i unplugged straight the battery cable.After going back home, i tested all the ESCs with the DJI assistant software using a good motor and the result message was "motor parameters are OK".1) does that mean that my ESCs are indeed ok and i can use them again?After my cross checks i will need 2 new motors.So, i need to find what caused these 2 fried motors.2) in order to avoid cutting the long cable of the ESCs, i wrapped it around the quadcopter arm. Can this cause a fried motor?3) is there a chance that with the prop attaching to ground and the quadcopter keep working, the fried motor was caused by the fact that the ESC kept sending signal but the motor/prop couldnt follow???4)is there a chance that the motors started overheating/frying while the quadcopter was on air? Is that possible according to my specs? DJI says that the E310 kit is suitable both for 3S and 4S batteries and for weights up to 2,5kg.Could you please help me find my answers?Thank you very much
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APM Pixhawk is already there as far as take off vertical is concerned. It's not like DJI in that you need to put it in GPS mode, in case you don't want to use it you don't have to.
I took my 3DR Quad out of the box put the props on and took off in Loiter mode on the first flight and most other flights. The 50% throttle position tells the FC to take off.
In the default configuration you should have GPS lock if the copter arms. I use Mission Planner or Droid Planner.
The modes you are using don't control the copters location so you need to do it yourself. It will not hold altitude like a plane.
If you want it to be stable use GPS but maybe that's not what your wanting.
Good point Darrell, thanks for providing another perspective.
No doubt a total DJI system is 'rail like'. APM will get there, or close to it, after a few flights and tuning.
I almost requested 'DN' to run the 'motors' test from CLI but thought I remember it being taken out. CLI was removed from ACv3.3 according to this reply by TCIII over on the support forum.
DN, you might also consider some form of tether. I used an old ballast from a fluorescent light, some string, and a clip to hook onto a leg. This limited how far the copter could go before trying to drag the ballast. Once I got comfortable with hovering, I never needed it again.
I've been spending the bulk of my time with fixed wing aircraft and when I want a rotary wing fix, I break out my Heli-Max 1SQ. No autopilot, just me on the sticks. That thing will get you muscle memory tuned up quickly.
I am building DJI550 FPV ship right now - APM 2.6. Have not bothered blogging it here as there is not much new innovation to it. It is hilarious how tech gets stale so quickly.
-=Doug
Darrell Burkey > R. D. StarwaltAugust 27, 2015 at 5:24am
The motor test is in the Mission Planner now. It's under 'Initial Setup', 'Optional Hardware' (last option). I don't think DN needs to use it though as his copter wouldn't fly at all if he had the motor order/direction or props wrong. I didn't ask him if he did the ESC calibration though which is an important step.
Drone newbie > Darrell BurkeySeptember 3, 2015 at 12:33pm
Dear Starwalt and Darell,
here we go.. I tried to fly again and I discovered that mostly it was my fear that made me think that things are not good at all with my quad.. So, today I realised that I am actually in a pretty good path considering that I am a newbie.
Today , I tested my quad in two modes, the stabilize and the AltHold.
1. In stabilize mode I just needed to put some throttle to quickly go above ground effect and then it could fly. What I discovered in stabilize mode is that :
a) I couldnt make it hover steady in an acceptable degree. Initially I was flying with the default linear throttle curve and then I switched to a more gradual style curve. In both ways I couldnt find that magic point of the throttle stick where the quad would hover. Either it would go up or down.. Any reasons for this ???
b) It would also move to a horizontal direction as well. FOr this I wanted to try the Auto Trin/ Save trim features of APM but there was some wind and I didnt try it. Do you have to propose another solution as well ??? Is Auto trim going to fix this issue ??
2. In AltHold mode I just needed to put the throttle stick to 100% in order to make the quad go up.. The climbing speed I have set for my quad when in AltHold mode is 50cm/s which is the minimum possible. What I discovered in AltHold mode is that:
a) It could hover quite well when I had the throttle stick in the middle , but like in the stabilize mode, the quad would also move into a horizontal direction. Again, will this Auto/Save trim process will fix this ???
3. During my today flights I connected the battery to the APM three times. Obviously I disconnected the battery two times in order to check the voltage with a voltmeter. So my three sessions I guess created 3 dataflash log files that I am attaching..
During my second and third session while flying, I noticed that my quad was descending although I was putting more and more throttle. I noticed that as it was descending, it didnt descend vertically and it was also moving in a horizontal direction.. I guess this will be fixed with the Auto/Save trim process , as with the stabilize and AltHold mode.. Correct ?? So, these descendings made me suspect that the quad probably had switched to Land mode. And when I was back home I checked the log files and indeed you can see that during the second and third session the Land mode has been triggered.. But why did it switch to Land mode?? When I finished my session my battery was at 14.9V and my Battery failsafe trigger in APM is set to 14V ... Can you propose any reasons why it did switch to Land mode ??? Could it be that my battery by having 10C it cannot provide sufficient power instantly and therefore the APM switches to Land mode ???
4. Also, in the log files I compared the DAlt, Alt and BarAlt to check the behavior of my quad in Stabilize and AltHold modes... I saw that when the quad was in Stabilize mode, the DAlt curve is not perfectly following the Alt and BarAlt curves... What does this mean ?? What should I correct ??
However, when in AltHold mode, all three curves are quite similar.. By seeing my log files, is there something that you would like to mention. DO you see something wrong that I cant see yet as I am still a newbie ???
I also noticed that the throttle of my turnigy 9XR was ectremely sensitive..i used the althold mode of apm, and i was slowly and gradually increasing throttle.. Suddenly the quadcopter started going up quite fast... And then when gradually decreasing throttle it did the opposite.. Is this extreme sensitivity an issue of my turnigy 9xr or an issue of my apm flight controller??
Alt hold modes depend on the tolerance/sensitivity of the sensor used to determine/maintain the altitude.
The quest for the perfect sensor continues and depending on the installation, noise can cause variation in position.
As your battery depletes, expect to increase the throttle as the upper and lower limit of the sensor is explored. The aircraft does not have a CNC machine level of performance. Do not expect millimeter position hold with today's technology. This is very common in Stabilized mode and with 'toy' copters.
What you describe still sounds like 'hunting' based on the trigger points of the algorithm. You might want to look at the log data for this event. You can and will learn much about your aircraft from the logs.
I would also dig into the calibrations for the DJI ESC as employed with APM. You may have a unique setup. DJI obviously made their products to work with their flight control electronics -- NAZA.
-=Doug
Drone newbie > R. D. StarwaltAugust 26, 2015 at 2:37pm
So, I have some updates to my problems... After replacing the two faulty motors and setting up again my quadcopter, I tried again to make a flight in Stabilize mode in order to see how the quadcopter behaves.. In my video you can see the attempts I have made https://www.youtube.com/watch?v=jK5kS9UgFiE
In all the attempts I was just gradually increasing the throttle channel without touching the yaw, pitch, and roll channels at all. Therefore, I would expect my quadcopter to start lifting vertically in an acceptable way without moving in other directions...As you can see in my video, the time just before the quadcopter starts lifting, it sounds like it cannot lift and also like vibrating and when it starts to lift, it also moves in forward or another direction. I checked the arducopter wiki pages, and I tried to recalibrate the radio but nothing changed...
Could you suggest me what causes this behavior and how can I correct this ???
I haven't played with PID values and I'm using some default values. I also haven't done any autotrim procedure. Is this needed ???
Just for reminding my setup is:
DJI F450 frame with its extension legs DJI E310 tuned propulsion kit ( 2312 motor, 420S ESC, 9450 props) APM 2.6 flight controller with gps module Multistar 10000mah 4S 10C battery TURNIGY 9XR radio with FRsky DJT transmitter and V8FRii receiver
It is unreasonable to think you can only input throttle and have the aircraft go only up.
You cannot expect the aircraft to go up like on a rail. The reality of the air currents and your frame do not permit this. The aircraft *will* shift around in many ways while going up, even in Stabilized mode. You will learn to control these shifts with your TX sticks and at first is can seem like something is wrong.
Your video looks like typical operation startup flights to me. Does the copter go in the correct direction if you input a command? The vibrations are not uncommon for early flights with APM. There was an 'auto-PID' type of operation depending on how long the arming command was active... not sure if it is still in the latest release.
I do recommend trying early flights over grassy areas because there are fewer air deflections on that surface. You can also relax more and not worry about flying off the roof where you are testing. Once the copter is 1 or 2m in the air, it should relax and not shift around so much. You are above ground effect currents at that point.
It looks like your propellers on are correctly but I am not certain which way is 'Front' as seen in the video.
When I started up my first quad with APM, I had several things wrong. Eventually fixed, once I was able to get into clean air, my skill increased and as the APM 'self calibrated' the PIDs, I could eventually take my hands completely off the sticks and simply watch it hover.
Please post a good photo and indicate which part of the copter is 'Front' showing all the propellers.
Begin flying only in Stabilized Mode. The other modes come later when you have more skill.
-=Doug
Darrell Burkey > R. D. StarwaltAugust 26, 2015 at 5:16pm
Actually, if you have ever flown a copter with a DJI controller you can indeed expect it to go up like it was on a rail. But that's because DJI defaults are to take off in GPS locked mode. But that's another story altogether.
I watched your video and I really think that everything is just fine. Your issue here is probably just being a bit new with copters as RD stated above. If you want to take off in Stabilise mode you need to give it a good amount of thrust to get it up in the air and then it will calm down a bit. I'm confident an experienced pilot could take that copter and fly it just fine. It's difficult when you are new as you want to take things easy at first but that's just not how copters fly.
You really need to take it out to a large grassy field so you have some space to work with it. Taking off in Stabilise is no problem but it takes a bit of skill and getting used to. I think people who start with APM end up as better pilots as they don't end up depending on GPS modes to do the flying.
There's actually nothing wrong with taking off in GPS modes like loiter or PosHold. I do it all the time. You just have to make sure you have satellite lock. Are you using a ground station so you can see how many satellites you have and that everything is OK before you take off?
But keep in mind that the throttle works much differently when in Loiter or PosHold. When taking off you have to raise the throttle quite a bit, almost to 50% and the flight controller will apply the thrust as needed to do the take off. There's a large dead zone in the throttle in these modes as you aren't directly adjusting the throttle. Instead you are giving feedback to the flight controller to lower or raise the height and the flight controller will do the rest. By comparison in Stabilise mode you are connected directly to the throttle.
I know it sounds confusing. Have a good read on the Wiki about the different flight modes. If at all possible, try and find someone else who has some experience to help you out on your first flights. These are fairly complex devices and there's a lot to learn in the beginning.
In summary, I think you are doing better than you may think. The copter looks fine, you just need to take off with a bit more confidence in a much larger area so you have time to use the controls. If you can make sure that the copter has GPS lock I think you might actually prefer taking off in Loiter or PosHold but remember, you have to raise the throttle quite a bit and be prepared for it to really take off. Others may disagree about this but if you are around anyone from the DJI world, that's just standard procedure. There's a bit of a mind set difference between people using DJI systems and the DIY type of person.
Again, if you can find someone with a bit of experience to help you on your first flights that would be really good. Best of luck and let us know how you go.
I do not have a DJI drive system. Looking at their webpage regarding the ESC:
Smart ESCs with integrated sensors and patented algorithms transmits real-time diagnostics of propulsion system status. Revolutionary sine-wave drive architecture reduces power consumption and increases efficiency of all maneuvers.
This *may* imply the motors provide feedback to the ESC although looking at the motor picture (very nice motor BTW) I do not see any tach feedback line. If the ESC senses RPM, it must be through other means than a tach pulse - likely back EMF.
Assuming, again, the ESC could tell the motor was not at the correct RPM, it might try to push more current to the motor for the same command signal from the APM. This is speculation on my part.
If you truly saw smoke, it was probably due to overheated insulation on the motor windings.
I would bench test the system or at least tether/gimbal mount the copter and run it up to similar RPM.
With a rigid test jig, you can find out if you have a failure and not risk the entire aircraft.
Replies
APM Pixhawk is already there as far as take off vertical is concerned. It's not like DJI in that you need to put it in GPS mode, in case you don't want to use it you don't have to.
I took my 3DR Quad out of the box put the props on and took off in Loiter mode on the first flight and most other flights. The 50% throttle position tells the FC to take off.
In the default configuration you should have GPS lock if the copter arms. I use Mission Planner or Droid Planner.
The modes you are using don't control the copters location so you need to do it yourself. It will not hold altitude like a plane.
If you want it to be stable use GPS but maybe that's not what your wanting.
Good point Darrell, thanks for providing another perspective.
No doubt a total DJI system is 'rail like'. APM will get there, or close to it, after a few flights and tuning.
I almost requested 'DN' to run the 'motors' test from CLI but thought I remember it being taken out. CLI was removed from ACv3.3 according to this reply by TCIII over on the support forum.
DN, you might also consider some form of tether. I used an old ballast from a fluorescent light, some string, and a clip to hook onto a leg. This limited how far the copter could go before trying to drag the ballast. Once I got comfortable with hovering, I never needed it again.
I've been spending the bulk of my time with fixed wing aircraft and when I want a rotary wing fix, I break out my Heli-Max 1SQ. No autopilot, just me on the sticks. That thing will get you muscle memory tuned up quickly.
I am building DJI550 FPV ship right now - APM 2.6. Have not bothered blogging it here as there is not much new innovation to it. It is hilarious how tech gets stale so quickly.
-=Doug
The motor test is in the Mission Planner now. It's under 'Initial Setup', 'Optional Hardware' (last option). I don't think DN needs to use it though as his copter wouldn't fly at all if he had the motor order/direction or props wrong. I didn't ask him if he did the ESC calibration though which is an important step.
Dear Starwalt and Darell,
here we go.. I tried to fly again and I discovered that mostly it was my fear that made me think that things are not good at all with my quad.. So, today I realised that I am actually in a pretty good path considering that I am a newbie.
Today , I tested my quad in two modes, the stabilize and the AltHold.
1. In stabilize mode I just needed to put some throttle to quickly go above ground effect and then it could fly. What I discovered in stabilize mode is that :
a) I couldnt make it hover steady in an acceptable degree. Initially I was flying with the default linear throttle curve and then I switched to a more gradual style curve. In both ways I couldnt find that magic point of the throttle stick where the quad would hover. Either it would go up or down.. Any reasons for this ???
b) It would also move to a horizontal direction as well. FOr this I wanted to try the Auto Trin/ Save trim features of APM but there was some wind and I didnt try it. Do you have to propose another solution as well ??? Is Auto trim going to fix this issue ??
2. In AltHold mode I just needed to put the throttle stick to 100% in order to make the quad go up.. The climbing speed I have set for my quad when in AltHold mode is 50cm/s which is the minimum possible. What I discovered in AltHold mode is that:
a) It could hover quite well when I had the throttle stick in the middle , but like in the stabilize mode, the quad would also move into a horizontal direction. Again, will this Auto/Save trim process will fix this ???
3. During my today flights I connected the battery to the APM three times. Obviously I disconnected the battery two times in order to check the voltage with a voltmeter. So my three sessions I guess created 3 dataflash log files that I am attaching..
During my second and third session while flying, I noticed that my quad was descending although I was putting more and more throttle. I noticed that as it was descending, it didnt descend vertically and it was also moving in a horizontal direction.. I guess this will be fixed with the Auto/Save trim process , as with the stabilize and AltHold mode.. Correct ?? So, these descendings made me suspect that the quad probably had switched to Land mode. And when I was back home I checked the log files and indeed you can see that during the second and third session the Land mode has been triggered.. But why did it switch to Land mode?? When I finished my session my battery was at 14.9V and my Battery failsafe trigger in APM is set to 14V ... Can you propose any reasons why it did switch to Land mode ??? Could it be that my battery by having 10C it cannot provide sufficient power instantly and therefore the APM switches to Land mode ???
4. Also, in the log files I compared the DAlt, Alt and BarAlt to check the behavior of my quad in Stabilize and AltHold modes... I saw that when the quad was in Stabilize mode, the DAlt curve is not perfectly following the Alt and BarAlt curves... What does this mean ?? What should I correct ??
However, when in AltHold mode, all three curves are quite similar.. By seeing my log files, is there something that you would like to mention. DO you see something wrong that I cant see yet as I am still a newbie ???
Many many thanks for your support..
session_1.bin
session_2.bin
session_3.bin
I also noticed that the throttle of my turnigy 9XR was ectremely sensitive..i used the althold mode of apm, and i was slowly and gradually increasing throttle.. Suddenly the quadcopter started going up quite fast... And then when gradually decreasing throttle it did the opposite.. Is this extreme sensitivity an issue of my turnigy 9xr or an issue of my apm flight controller??
Alt hold modes depend on the tolerance/sensitivity of the sensor used to determine/maintain the altitude.
The quest for the perfect sensor continues and depending on the installation, noise can cause variation in position.
As your battery depletes, expect to increase the throttle as the upper and lower limit of the sensor is explored. The aircraft does not have a CNC machine level of performance. Do not expect millimeter position hold with today's technology. This is very common in Stabilized mode and with 'toy' copters.
What you describe still sounds like 'hunting' based on the trigger points of the algorithm. You might want to look at the log data for this event. You can and will learn much about your aircraft from the logs.
I would also dig into the calibrations for the DJI ESC as employed with APM. You may have a unique setup. DJI obviously made their products to work with their flight control electronics -- NAZA.
-=Doug
So, I have some updates to my problems... After replacing the two faulty motors and setting up again my quadcopter, I tried again to make a flight in Stabilize mode in order to see how the quadcopter behaves.. In my video you can see the attempts I have made https://www.youtube.com/watch?v=jK5kS9UgFiE
In all the attempts I was just gradually increasing the throttle channel without touching the yaw, pitch, and roll channels at all. Therefore, I would expect my quadcopter to start lifting vertically in an acceptable way without moving in other directions...As you can see in my video, the time just before the quadcopter starts lifting, it sounds like it cannot lift and also like vibrating and when it starts to lift, it also moves in forward or another direction. I checked the arducopter wiki pages, and I tried to recalibrate the radio but nothing changed...
Could you suggest me what causes this behavior and how can I correct this ???
I haven't played with PID values and I'm using some default values. I also haven't done any autotrim procedure. Is this needed ???
Just for reminding my setup is:
DJI F450 frame with its extension legs
DJI E310 tuned propulsion kit ( 2312 motor, 420S ESC, 9450 props)
APM 2.6 flight controller with gps module
Multistar 10000mah 4S 10C battery
TURNIGY 9XR radio with FRsky DJT transmitter and V8FRii receiver
AUW is 1,6kg
Thank you very much for your help
It is unreasonable to think you can only input throttle and have the aircraft go only up.
You cannot expect the aircraft to go up like on a rail. The reality of the air currents and your frame do not permit this. The aircraft *will* shift around in many ways while going up, even in Stabilized mode. You will learn to control these shifts with your TX sticks and at first is can seem like something is wrong.
Your video looks like typical operation startup flights to me. Does the copter go in the correct direction if you input a command? The vibrations are not uncommon for early flights with APM. There was an 'auto-PID' type of operation depending on how long the arming command was active... not sure if it is still in the latest release.
I do recommend trying early flights over grassy areas because there are fewer air deflections on that surface. You can also relax more and not worry about flying off the roof where you are testing. Once the copter is 1 or 2m in the air, it should relax and not shift around so much. You are above ground effect currents at that point.
It looks like your propellers on are correctly but I am not certain which way is 'Front' as seen in the video.
When I started up my first quad with APM, I had several things wrong. Eventually fixed, once I was able to get into clean air, my skill increased and as the APM 'self calibrated' the PIDs, I could eventually take my hands completely off the sticks and simply watch it hover.
Please post a good photo and indicate which part of the copter is 'Front' showing all the propellers.
Begin flying only in Stabilized Mode. The other modes come later when you have more skill.
-=Doug
Actually, if you have ever flown a copter with a DJI controller you can indeed expect it to go up like it was on a rail. But that's because DJI defaults are to take off in GPS locked mode. But that's another story altogether.
I watched your video and I really think that everything is just fine. Your issue here is probably just being a bit new with copters as RD stated above. If you want to take off in Stabilise mode you need to give it a good amount of thrust to get it up in the air and then it will calm down a bit. I'm confident an experienced pilot could take that copter and fly it just fine. It's difficult when you are new as you want to take things easy at first but that's just not how copters fly.
You really need to take it out to a large grassy field so you have some space to work with it. Taking off in Stabilise is no problem but it takes a bit of skill and getting used to. I think people who start with APM end up as better pilots as they don't end up depending on GPS modes to do the flying.
There's actually nothing wrong with taking off in GPS modes like loiter or PosHold. I do it all the time. You just have to make sure you have satellite lock. Are you using a ground station so you can see how many satellites you have and that everything is OK before you take off?
But keep in mind that the throttle works much differently when in Loiter or PosHold. When taking off you have to raise the throttle quite a bit, almost to 50% and the flight controller will apply the thrust as needed to do the take off. There's a large dead zone in the throttle in these modes as you aren't directly adjusting the throttle. Instead you are giving feedback to the flight controller to lower or raise the height and the flight controller will do the rest. By comparison in Stabilise mode you are connected directly to the throttle.
I know it sounds confusing. Have a good read on the Wiki about the different flight modes. If at all possible, try and find someone else who has some experience to help you out on your first flights. These are fairly complex devices and there's a lot to learn in the beginning.
In summary, I think you are doing better than you may think. The copter looks fine, you just need to take off with a bit more confidence in a much larger area so you have time to use the controls. If you can make sure that the copter has GPS lock I think you might actually prefer taking off in Loiter or PosHold but remember, you have to raise the throttle quite a bit and be prepared for it to really take off. Others may disagree about this but if you are around anyone from the DJI world, that's just standard procedure. There's a bit of a mind set difference between people using DJI systems and the DIY type of person.
Again, if you can find someone with a bit of experience to help you on your first flights that would be really good. Best of luck and let us know how you go.
I do not have a DJI drive system. Looking at their webpage regarding the ESC:
This *may* imply the motors provide feedback to the ESC although looking at the motor picture (very nice motor BTW) I do not see any tach feedback line. If the ESC senses RPM, it must be through other means than a tach pulse - likely back EMF.
Assuming, again, the ESC could tell the motor was not at the correct RPM, it might try to push more current to the motor for the same command signal from the APM. This is speculation on my part.
If you truly saw smoke, it was probably due to overheated insulation on the motor windings.
I would bench test the system or at least tether/gimbal mount the copter and run it up to similar RPM.
With a rigid test jig, you can find out if you have a failure and not risk the entire aircraft.
-=Doug