I am building a quad with hobbywing x11 plus for lifting large payloads. The quad with no payload weighs about 25kg，with payload weighs 60kg, but up till now it flies with no payload. Its axial size is 1620mm，and uses 4314 propellers and 14s batt. I use Mission Planner’s ‘Initial Tune Parameters’ to calculate initial params and write to FC. For safety reasons, I limit the throttle to 1500. After some failure in initial flights, i changed some params in the param list. When flying it, it seems that it is ok in Stabilize mode and AltHold modes, but not so good in Loiter mode. Its roll and pitch angles are doing a ±5 deg oscillation and its horizontal position is vibrating too, travelling back and forth around a small region.
Here are my questions:
How can i tune my quad to eliminate the above phenomenon and fly more stable?
I hear there is an ArduPilot methodic configurator software, where can i get it?
Is there a detailed explanation about the PIDs in the extended tuning under the config menu of Mission Planner? For example the units of these PIDs？
The bin log files can record PIDs. What are their meanings and units?
Thanks a lot.
the propellers are not level, Motor 3 and 4 are spinning higher to counter the auto-yaw.
What is your flight controller hardware (fmuv3 001E0039 3138510F 33363933)?
BATT_MONITOR,0 # minimum, enable it
MOT_HOVER_LEARN,2
MOT_PWM_MAX,1500 # unusual value, should be manufacturer value
MOT_PWM_MIN,1000 # unusual value, should be manufacturer value
MOT_PWM_TYPE,0 # PWM type
MOT_SPIN_ARM,0.1 # Have you used the motor test without the propeller to set them?
MOT_SPIN_MIN,0.15 # Have you used the motor test without the propeller to set them?
LOIT_BRK_DELAY,1 # consider change to 0.3
LOG_FILE_DSRMROT,0 #consider use 1
INS_LOG_BAT_MASK,0 # have you done the noise and vibration reduction?
INS_LOG_BAT_OPT,0
FLOW_TYPE,5
RNGFND1_TYPE,10
It could be due to the limit of the throttle to 1500, as a result, the hover thrust learn becomes unusual.
you have optical flow and lidar sensors enabled, are you locking position with GPS or Flow sensor? The flow sensor seems like is not calibrated.
Thanks. I’ve spent some tome on quad but new to this forum. Really amazing software that can solve key problems in quad tuning. Hope to make good use of it and fly my quad smoothly.
My fc is the very old px4 2.4.8. I guess it can support quick tune but i am afraid of doing it. Optical flow was once used but now it only provides altitude. The reason i limit the throttle is because the motor is powerful and i am afraid by mistake someone raises throttle too high and it shoots in the air.
The following is the quad’s history till now. Last October we bought the material and started assembling them. Our original plan was building a quad that can carry 30kg, the quad itself weighs about 20kg. So we chose hobbywing x11plus, its thrust is about 15kg at 50% throttle so the overall thrust is 60kg. At that time i thought it had little difference than the quads i built before. At the first flight, i set it in stabilize mode and raised the throttle. Suddenly one motor seemed to be accelerating very fast and pulled the vehicle into the air and made it turn upside down and hit the ground, breaking a propeller.
After this incident, i think first the reason of the crash is that the quad is too light(<30kg) compared to its thrust which makes it hard to control. The datasheet of x11plus even has no data about such low thrust(7-8kg). So afterwards we limit the throttle to 1500. The other reason maybe wrong w
Then we made a test stand to measure the motor thrust and collected the data. After this we did some flight tests, the stab and althold mode flew well. But in Loiter mode another crash occurred, the quad was in a rapidly growing oscillation and finally turned upside down. i analyzed the reason, maybe the horizontal pos control loop is feeding back too strong. i decreases some pid params such as posxy and velxy pids. With modified params we flew Loiter mode again, this time it did not crash but was in a slow dancing, with roll and pitch amplitude about ±5 deg. i decreased the params more and the situation did not improve, the quad still dances in the horiz plane and This is where i am now.
Lots of things happened after my last post. We wanted to test whether the quad can carry our 30kg load, so we tied a 30kg weight on it. We tested the Loiter mode, the good news is that it lifted off the ground and danced like before. It is obvious that it could keep its altitude, but horizontally its pos keeping was not so good. It seemed that it circles in the Loiter mode. The bad news is that after about 1 min of weight carrying flight, it suddenly lost its power and fell on the ground. Later we found out that the batt uses an improper power plug, the power line was very thin, the high current produced so much heat that the soldering melted. Fortunately the altitude was very low that the damage on the quad was negligible. Can you please suggest a brand of batt that suits our needs?
So we decided to buy a better batt and uses proper connectors that can carry larger currents. We used new batt to test weight carrying. In loiter mode, it spun so we had to stop Loiter. Later we found that the compass wire was loose and free to rotate. When we fixed this and tried new flights the message “Accels inconsistent” appeared. After many tries it was still there we had to take it back to the lab, indoors. There that message disappeared. From that flight, Loiter mode did not succeed, with or without new batt, with or without test weight. If switched to Loiter, the quad raised up its head and flew backwards with pitch angle rapidly increasing, running to me as i was operating RC at its back. I will post .bin files for you to see, hope to get some advices.
1 min weight carrying and soldering melt
what the quad flies now, see last seconds when switched to Loiter mode
So we decided now to do some serious tunings and use new fc in addition to the old px4 2.4.8. Can you please tell me is CUAV V5+ good enough?
And then, some “theoretical” questions wishing to get your support. Recently I read some posts in this forum about heavy quad tuning and found lots of things new and inspiring, this is where I can get some support and help.
First, are there some books or articles that explain the control model behind the arducopter fc? I think there must be some reference books or models (such as Simulink models) with all these params for tuning.
Second, for these large propeller quads, how do the params change compared to smaller ones? Which ones get larger and which ones get smaller? Is it true that PIDs increase as prop diam increases? Should the integral term XXX_imax change? And what about ATC_ANG_R(PY)_MAX？
For my quad, the dummy weight is about 30kg, hobbywing x11plus motor, hover throttle is about 1375. Can you please suggest some key params for its Loiter mode? I think it flew well in Stabilize and AltHold mode.
Another question is for two states of the quad, with or without test weight, how can one set of params fit both?
Thank you for your advices.
Yes px4 2.4.8 is very old but it is the one I used most often. Other fcs are good but quite expensive… I will use a new cuav v5+ later.
Optical flow was originally for indoor flights but now we did not use it any more.
The dummy weight of quad is about 32kg now, hover throttle about 1350-1400, do I need to add more for dummy weight?
Thank you.
Good connectors, XT60 for continuous 60A, XT90 for 90A, XT150 for 150A. You didn’t mention the entire drone weight; you mentioned your payload is 30 kg.
So, if your drone’s entire takeoff weight is 30 kg, an XT60 connector will do; of course, your drone’s entire weight is not 30 kg. Solder volume matters for correct Ampere flows.
Please check the correct AWG cable diameter size for the right worst-case Ampere usage.
Bigger AH, the battery is heavier. Your solder melting has nothing to do with the battery. It is solder volume, connector type, and cable diameter size issue.
For your drone weight and size, I think a H7 STM chip is better.
If the drone has a low noise and low vibration, a Quiktune will help after testing Alt-hold before a Autotune.
Small or Big, the configuration goes through the same process. Initial parameters, test alt-hold, harmonic notch filter, Quiktune, Autotune, Quiktune repeat assuming users know the motor to propeller matching, ESC, propulsion ratio.
You can consider copying my settings. Although I am still experiencing some issues, my basic settings have been in use for 2 years and are very secure. The problem I encountered was due to a recent change in my blade design, which only occurred when the speed exceeded 20 meters.
You can consider using two TX150 plugs or QS8 QS9 QS10 plugs, both of which can be used safely. Because this configuration flies to 70 yards and the current is less than 200A
Thank you for your interest in my quad.
It is really good to have a long time project and have enough resources to do it.
I am just into this heavy quad subject a while and did not have the chance to do blade optimization.
Do you mean “frame param file” when you mentioned “copy my settings”?
If the answer is yes, can you please share it with me?
It will be of great help. Thank you.
Thank you for your new reply to my topic.
Just finished IMU temp calibration for both fcs, px4 and v5+.
Planned to buy H7 fcs, cube orange really cost some money …
There is cheaper Flying RC H7D H743 fc, but don’t if it is reliable.
Will do test flight and follow the steps when rain stops.
The dummy weight of my quad is about 30kg. The planned load is about 30kg, too.
It takes off with dummy weight, flies a while, then carries the load for some time, releases the load, and returns.
Especially prop 3. Thank you.