After several flights of my Tarot quad, I found it to be difficult to control due to the motors not running smoothly resulting in excessive vibration. All this time I was thinking that it was due to the aircraft being untuned, but tweaking the PIDs didn’t seem to help. So, I ran a static test where I secured the aircraft to the floor in my basement and throttled up the motors. They were running just as it was in flight. I then tan the Motor Test using Mission Planner, running each motor at 20% for 4 seconds - each motor ran smoothly. This lead me to believe that my propellers are not properly balanced.
Balancing large foldable propellers is a challenge because the hub, which is in two pieces, does not have a hole that runs completely through the center - the top piece is solid. So I took a spare top piece and drilled a hole through it so that I can run the balancing shaft through it.
Testing the first propeller, it would not come to a rest completely horizontal - one end was an inch below the other end. I will have to add a little weight to the light end until it balances completely. I will repeat the process with the remaining three propellers and then run the static test again to see if this solves the problem.
On another note, I found landings to be extremely difficult as the landing struts were almost vertical which allowed the copter to tip over upon touchdown if there is the slightest bounce. I figured out how to adjust the struts so they have a wider stance which should make landings much easier.
Well, that was a bust. After painstakingly balancing my Tarot 17" foldable props I once again tried a static test. First, I ran the motor test using 25% power for 4 sec on each motor then on all motors at once. They seemed to run fine so I armed and throttled up the aircraft - there was no discernable difference.
So, at this point, I believe that there is nothing wrong with the propellers, motors or ESCs. I am going to try to run the motor/compass calibration which requires throttling up the aircraft, to see how the motors behave. I’m back to speculating if I can improve their operation by tweaking the Throttle Accel parameters on the Mission Planner Extended Tuning Page. If this fails then I will consider replacing the F.C. with a more current device, but this will require pretty much complete disassembly in order to get to the power distribution module so I can replace the power module.
Does anyone have a suggestion for a replacement flight contoller? I don’t want to mess around with one that requires the S-Bus protocol as I don’t want to add yet another device (encoder).
You need to post a .bin log file, and you dont need to run motor/compass calibration you just do basic compass calibration from MP and later when your vehile is flyable you will do Magfit. Try to lower default gains by 50% including D term which propably is your issue. Also if you too much soft mount your FC that can make problems with motors vibrating also. But without a log file no one here can help you.
I ran the motor/Compass calibration only to see if the motors behaved differently, which they did - they ran smoothly as I would hope they would out in the field. The fact that they did run okay during the test eliminated the possibility that the propellers, motors or ESCs were somehow contributing to the problem.
I now believe that there is a different logic path within the F.C. firmware that controls the motors when arming and flying as opposed to running any of the Mission Planner tests involving the motors. So, I’m back to experimenting with the PID settings that affect the throttle. If I’m not able to get good results tweaking the PIDs then I will try re-flashing the firmware and starting over; if that fails then I will consider trying a different (currently supported) controller; this is my last resort as there will be a significant cost (around $200) plus complete disassembly of the aircraft in order to get to the power distribution board, replace the power module as well as possibly replacing the GPS/Compass module, depending on the F.C. I choose.
Motor test tab will just test your motors without any PID. If they work fine in motor test tab then you probably have problems with PID. I told you already lower stock PID’s by 50% and try to take off and hover. You will not get better resaults with reflashing firmware or changing FC. Its a simple thing to post .bin log and we can see what is actualy happening but you refuse to do it, and i guess you will have to figure it out on your way.
I just uploaded a .bin file. I will look at the PIDs and see what lowering values do. I’m guessing that I can experiment with the pids while keeping the aircraft secured to the ground. If I Can get the motors to run more smoothly while tied down, I will try to take it to the filed and try a flight.
If you can attach a .bin flight log directly usually there is something wrong with it. Which is the case here. Remind us what Flight Controller this is. .
That would be a wrong guess. You can learn nothing with it secured to the ground other than the motors run.
So, what I’ve determined so far is that by bypassing the PIDs logic, running the Motor Tests in Mission Planner, the motors run just fine. But when I arm and throttle up, the motors exhibit this hesitation phenomenon regardless of whether the copter is restrained for free to fly.
Whatever remedial action is required, it should be apparent when I throttle up the motors regardless of whether the aircraft is restrained or not. Or am I missing something? Are you suggesting that the PID values are not the problem? I’m inclined to agree since I just ran a series of tests, modifying the Throttle Accel and Throttle Rate values in the Extended Tuning page and there was no perceived difference in behavior.
I don’t know what the problem is but running the motors with the Transmitter when secured to the ground won’t tell you anything including telling you the motors are running rough. Unless its in free flight, or using Motor Test, what the motors do can be quite random.
Typically at this point we would ask for a .bin flight log of the craft at hover after the Initial Tune parameters have been set. But, you don’t have those parameters available. You could reset all to default and make a hover flight and post a link to that flight but there will not be many around familiar with the meager amount of information in the log from that version of firmware.
Like @dkemxr tell you post your hardware first, and reset your parameters to default. Then lower Pitch,Roll,Yaw PID’s by 50% and try to hover for like 30 sec and see what heppand. Also with 3.2.1 firmware you will not make fly really good anyway, that is years old and unsupported.
I tried to reflash the firmware and start over, but was unsuccessful in doing so - I kept getting “Bad Firmware” messages, no matter what legacy version of Mission Planner I tried. do, I have decided to replace the APM controller with a more current device and use the most current version of Mission Planner.
I will have to wait until after the holidays to spring for a new controller as I have overspent my budget on this project. Once I get it and reassemble the aircraft, I will complete the necessary configurations - imu, radio, compass, etc. and then attempt a static run using default parameters and see what happens.