Servers by jDrones

Drift of quad in land mode

(Rick) #37

The desired attitude can get “dragged around” by the actual attitude. This is true for technical and safety reasons, which can prevent the drone from doing crazy maneuvers.

For example, in your case, if the desired altitude stayed at 40 meters, the drone would keep trying to descend by 100+ meters. But what if the measured altitude was wrong? The drone would try to fall into the ground. This “desired dragging” makes sure that the drone never tries to execute extreme maneuvers by ensuring that the desired and actual attitude are always reasonably close to each other.

(Ashwani gupta) #38

HI rick ,

       is there any way to check the capacity of my drone that how much wind it can take ? what kind of changes you are suggesting in parameters to increase the capacity keeping all the hardwares same ?

(Rick) #39

You can use eCalc to get an idea of your drone’s payload capacity. Otherwise, you can build a test stand to measure the maximum thrust of your motors.

There’s no real way to increase the drone’s payload capacity without changing hardware. It is limited by the motor’s performance and the weight of the drone.

(Ashwani gupta) #40

Hii Rick, Actually i don’t want to increase the lifting capacity of my drone rather want to improve the performance like fighting against the gust and even fly against the gusty wind, more stability, less vibration etc (keeping the power plant unchanged). Is there any suggestion from your side, link or some kind of reading stuff that you can provide me so that i may get some idea to incorporate the amendment that i mentioned above ?

(Ashwani gupta) #41

hi rick ,
i have a doubt about the vehicle performance. what will happen if i use a overpowered quad copter in auto mode (alt hold, pos hold) and in manual mode (stabilize and acro) ? How does it behaves ? If i want to forcibly use an overpowered copter what will be the consequence ?

(Hari .P) #42

Hi, Ashwini,
A perfectly tuned (i think it is a never ending process) Copter will perform well in any mode.
Pls post some photos & specs of the overpowered copter, so that the experts can chime in,
Best Wishes…


(Rick) #43

Stability and wind resistance is mostly a matter of tuning. There’s a long list of things that can improve the tuning of your drone; some of these things are quite advanced and are beyond most users.

  • Reduce vibrations
  • Tune PIDs and acceleration limits (Autotune will do this)
  • Tune filters (gyro filter, rate filter, notch filter. May require FFT analysis)
  • Characterize powertrain (MOT_THST_EXPO, MOT_SPIN_MIN, MOT_SPIN_MAX. Requires a motor test stand to do properly.)
  • Maximum performance tuning (THR_MIX_MAX, other output shaping parameters. Requires a lot of flight testing)

Most users do the first two, and those are usually the most important; as long as you get your vibrations low and run Autotune a few times, your copter should perform quite well. The other items require testing and analysis to do, but they can turn a good tune into a perfect one.

A very overpowered copter requires careful tuning to fly properly. This is because when the motors are running at very low throttle, the copter will have a limited ability to throttle down some motors when it is maneuvering or dealing with wind. This generally results in a drone that is a bit wobbly in wind and cannot perform precise maneuvers because its rotational acceleration will be limited.

It is possible to have a well-tuned copter that hovers at ~15% throttle, but it is difficult to do, and probably requires the 3 last items in my tuning list. If you want a powerful copter, is generally better to have a copter that hovers around 25% throttle.

(Ashwani gupta) #44

Thank you rick.
as per your suggestion i purchase a taranis Q X 7 ,transmitter with vibration damper and a carbon fiber frame with T-motors of 650 kv for 12-14’ of quad.
may be somewhere at the weekend i will assemble it and share a pic with you.
Thanks for your continue support. .

(Ashwani gupta) #45

Hii Rick,

what is the most stable firmware for pixhawk 2. recently i am moving slightly towards the professional drone with following component.
pixhawk 2
here plus rtk
tatto battery 10000 mah
taranis q x 7
turnigy 40 amp esc
vibration mount
pixy ir lock
rp lidar
px4 flow sonar
T motor 650 kv

(Ashwani gupta) #46

hi rich,
i attached here+ gps to the system but unable to do the compass calibration on AC3.5.5. Do you know how to fix this problem if you used it before ?

(Oldgazer) #47

Why don’t you tell us IN DETAIL what you are doing and EXACTLY what indications your are getting.

To give you a clue posting this: " i attached here+ gps to the system but unable to do the compass calibration on AC3.5.5. Do you know how to fix this problem if you used it before ? ", is like walking into a Doctor’s office and saying , “I don’t feel good.”

(Ashwani gupta) #48


i got a here+ rtk gps , that i attached to the pixhawk cube. while calibrating the compass the external compass is not calibrating, somei=time reaching to 33 % and stop forwarding and sometime it is reaching till 99%, giving a sad tune and restarting the calibration of the external compass.
now during this some time it is not allowing the internal compass also to get calibrated. when i am removing the external compass and calibrating only internal compass it is not showing any problem. more over while going for the live calibration it is leaving some white dot behind and the entire sphere is shifting very far from center. Due to this i am getting the offset value of external compass in 2000+. because of that i am not able to use this important hardware. Just for one trail i changed the firmware from 3.3+ to 3.5.7 but there was no change and problem is still the same.
that what all happening.

(Ashwani gupta) #49


I want to read about the description of options written in the temp option of mission planner. Do you have any link associated with that ? I want to read details description about the swarm, microdrone, moving base, follow the leader, inject ge etc. please send me any link if you are having ?

(Ashwani gupta) #50

Hi Hari,
Can you tell me what will happen to the performance of drone, if i will tune my FC by placing at the vehicle centre but using it at a different location then the center ?

(Hari .P) #51

As far as I know, moving fc by a few centimeters (not changing the orientation) won’t affect(?)
For Perfection- Tune once more !
Have you read this …

(Ashwani gupta) #52

Hi hari,

I am sharing four different logs of my quadcopter. These all four logs are associated with the same vehicle configuration with same payload.

What i have observed that for the same vehicle and same payload my motor’s balancing start deteriorating. First two log associated with the flight on 12th balancing was good, but on 13th it become worst and during second attempt made on 13th at 11:14 AM, it just crashed with very random behavior. The odd behavior observed was the undesired roll in the system during the take off and during the flight too. Though the last log will tell that there i s a GPS glitch but situation was not good even before the glitch. Why this odd behavior came into the system, while i did not change anything in the system ? Please help in finding that.

(Hari .P) #53

Hi, as I’m not the right person to analyze a log, some expert must chime in !.
Looking at your last log, it seems to me that motors 1 &2 are working hard to fight the yaw induced by motor 4 or 3 .
Are these motors upright ?

(Ashwani gupta) #54

ya motor was correct. I mentioned that there was no change in system in all four logs. Everything was exactly identical from hardware and payload side.

(Ashwani gupta) #55

BTW the values of motor trim pwm is given in flight log are corresponds to the actual numbering or the way we test our motor for direction.

(Terje Nilsen) #56

I got the same problem as in the heading (Drift of in landing mode)
I use NAVIO2, with 3.7ArduCopter, everything is calibrated and tuned, it HOLDS perfect at position.
The GPS logs, the drift, so that is not it…

I have tried with calibrated RC (Futaba) and with RC turned off and with NO RC (receiver removed) and Joystick in Qgroundcontrol. all ends up in the same situation, from 50m and down, when in landing mode, it drifts off depending on wind. Just before landing I turn on the RC and takes over, when possible, or switch mode, or hit a house…

This is very frustrating as it flies the mission close to perfect…

I tried with manual and auto tuning of the PIDs ( Auto was cool, my new favourite).

I belive there is a logic error, or something with the pitch/roll guard band that is too tight.
However the Autotuning went fine, and it also uses a pitch/roll guard band for repositioning.

Take off to 50m is perfect, no drift at all…