Ozzy,
Please set the parameters listed below to the values I’ve listed beside them. Please use the full parameter list window of mission planner to make the changes. If you see oscillations then cut the ANG_XXX_P parameter for that axis in half and try to fly with that. Fly with these settings ONLY and report back and provide a log.
ATC_ACCEL_P_MAX, 52000
ATC_ACCEL_R_MAX, 52000
ATC_ANG_PIT_P, 4.5
ATC_ANG_RLL_P, 4.5
ATC_RAT_PIT_D, 0
ATC_RAT_PIT_FILT,12
ATC_RAT_PIT_I,0.2
ATC_RAT_PIT_ILMI,0.08
ATC_RAT_PIT_IMAX,0.44
ATC_RAT_PIT_P,0
ATC_RAT_PIT_VFF,0.15
ATC_RAT_RLL_D,0
ATC_RAT_RLL_FILT,13
ATC_RAT_RLL_I,0.2
ATC_RAT_RLL_ILMI,0.08
ATC_RAT_RLL_IMAX,0.44
ATC_RAT_RLL_P,0
ATC_RAT_RLL_VFF,0.15
HI Bill,
I tried those changes you listed above and the shaking was bad, so I cut the ATC_ANG_PIT_P =2.25 but the shaking on the pitch stick correction was reduced by 50% only, so its still if I pull the Pitch stick back or release the pitch stick the heli will shake just like when you throw the cent on the floor will round and stop !
Hi Ozzie, based on your report, I don’t think the default parameters will work for your Heli. At least not on pitch and roll. So we will have to go back to basics and start from the beginning with the turning according to our turning wiki Tuning wiki
Set the pitch and roll P, I and D gains to zero. And set the ANG_PIT_P and ANG_RLL_P to 4.5.
I will leave it up to you as far as setting your Accel_max parameters and the input_tc (which used to be the RP_feel parameter as stated in the wiki). Going higher with the input_TC parameter will give a softer feel to the response. For heli’s I don’t think you want to go less than 0.15 for this parameter and probable no more than 0.3. But this is more for how you want the response to feel.
Initially let’s set these parameters on a little bit of the fast side so here’s what I recommend.
ATC_ACCEL_P_MAX, 80000
ATC_ACCEL_R_MAX, 80000
ATC_INPUT_TC, 0.15
ATC_RATE_R_MAX, 0
ATC_RATE_P_MAX, 0
After we finish tuning, You can adjust these to make the aircraft respond a little slower if you want. That won’t affect the tuning.
Perform the step titled “Setting VFF and ACCEL_MAX for Desired Pitch and Roll Response” except only adjust VFF for pitch and roll as it describes. Don’t adjust the accel_max parameters.
Once you complete this step please post the a log with some quick inputs in pitch and roll so I can see that you set VFF properly. The inputs should be fast 1/4 to 1/2 stick inputs that you should hold for a second before recovering. Be sure to give your self a big enough area for this maneuvering.
Hi Bill,
here is what happen; I set all your above values, PID to 0 except of the Yaw left it as is,
I increased ATC_INPUT_TC,0.18 and I changed back the ATC_ANG_PIT_P,4.5
also changed the both ATC_ACCEL_P_MAX,80000 ATC_ACCEL_R_MAX,80000 the problem reduced and I had about 20% shake when I ONLY let the stick go fast to its neutral center position…
the Heli fallow the stick moment fast and bring the heli back to its center potion and balancing or (shaking) little just like when you hit a hard brake in a car; after the car stop will shake little bit!
but the heli was very nice! I could flight it with ice on my heart!
so I tried the ALT Hold and the heli was doing OK! then I tried the POSHOLD and the heli was drifting left by 3-4 feets
but was very nice!! then I bring is back down and I re-placed the stock 600mm blades with 700mm blades since I have stretched 700 boom!
I flew it and it surprised me that the problem GONE!!
I was super happy and excited ! then I tried ALT hold and was OK again…
but here is the new problem ; when I switched to PosHold the heli was doing like a boat on the water! like stirring your cyclic stick and that circle become bigger and bigger and bigger till I switch to ALTHold then to Stab mode…
I know I should not try any other mode!, but Man I was so happy !! and want to see the next show!
its weird that this problem was not exists in the old stock blades!!! or maybe something changed!!
here is the logs and the parameters
Hi Ozzie, until we get the aircraft tuned please don’t fly in any other flight modes.
So what was the rotor speed for these flights? Did you change it between the different blades? You could try putting on the 600 blades and increase the rotor speed to see if that gets rid of the issue.
Ozzy,
Your rotor speed is pretty low and makes sense that your are seeing this oscillation in the pitch axis. Raise your rotor speed to 1500RPM for the 600mm blades and I suspect the pitch issue you are seeing will go away. I noticed you are using the RSC mode 1 which is a passthrough. Does your ESC have it’s own governor? I would urge you to move to RSC mode 2 if you are using an ESC with a governor.
So we can continue to try and tune your heli with the 600mm blades and 1150 RPM. We will have to make some adjustments to try to get rid of the pitch oscillation. Unless you want to tune it with the 700 blades. your choice.
yes I am on mode 1 and that was for CH8 input, I just changed now H_RSC_MODE, 2
which is set point… and since my ESC is a governed to 1500 RPM
its new ESC v4 and can set the rpm I want!
I would like to stay away from the stock blades because they are to small and since I stretched the heli to 700 why not use the 700mm blades will give me more stable heli and can carry more weight
also help lower the speed that will get me more minutes to fly the bird with!
so you think after changing the blades I should try to get the ATC_ACCEL_P_MAX, 52000 and the ATC_ACCEL_R_MAX, 52000
also ATC_RAT_RLL_IMAX to 0.44 and the ATC_RAT_PIT_IMAX to 0.44
and keep all other PID to 0 values?
of course the ATC_INPUT_TC, 0.18 and that should not effect other modes ?
here is new flight with no shaking or oscillating problems… looks like issuw was solved!
it dose drop and I had to giv more pitch to get it back up a little, also drifting to the left and back
So you changed your ESC to govern at 1500 RPM? If you plan on using the larger blades and want to be at a lower rotor speed, then set your rotorspeed you want now before we start tuning. A lower rotor speed is worst case. I wouldn’t go much lower than 1150 RPM though.
No. Leave the accel_max parameters where they are. Like I said before, we will tune at this higher rate and then you can lower the accels to what you think is good.
Yes these can be set to what they were. these don’t affect anything right now. Only when we start adding I gain.
Yes keep these zero
This is fine. we want to tune it with faster settings (i.e. Lower ATC_INPUT_TC values). then you can adjust it after we finish tuning if you think it is too fast.
I will look at your data from today. As long as you are planning to stay with the 700 mm blades at 1150 RPM then I can look at the logs from today and make sure everything is good to proceed.
Grate! I will double check my RPM setup in my hobbywing APP and see if its giving me real 1500 RPM, I can feel I have around 1150-1200 RPM on this setup since my motor and my Voltage with my pinion and main gear can’t giving me higher than 1200 RPM anyway!
and of course the Motor will not produce 100% energy so I will say 1150 RPM the top
I will install my RPM sensor today in my tail boom to read the exact RPM on my ideal 2 switch.
above is my new video with my logs hope you can see I let the stick go to center and the heli was not shaking at all!
it was loos a tiny bit but I can control it with ease!
Edit ; I will get the ATC_RAT_RLL_IMAX to 0.44 and the ATC_RAT_PIT_IMAX to 0.44 back today !
thank you
Ozzy
sorry for my fast posting here! but I just bring ATC_RAT_RLL_IMAX to 0.44 and the ATC_RAT_PIT_IMAX to 0.44 back and ATC_INPUT_TC = 15
and kept all PID =0
and flew it … it was big different and yeaaaa its fixed!
the heli was perfect this time, was super easy to fly and stable like a rock!
there is a little drifting I thing its normal since its only Stab mode
but otherwise it’s ready for the next step!
I believe this the problem was with the short stock thin blades… my other homemade Heli
had close to this problem and I changed the blades to bigger once and flying like dram with the SK720
the stretched tail along with the small flying rotor disk make it difficult to recover from stick movement !
now you think its time for the next mode?
Edit here is the latest logs and parameters for the latest flight
Thank you
Ozzy
There are two other params that I think you should change before proceeding.
ATC_RATE_P_MAX, 0
ATC_RATE_R_MAX, 0
These were non zero, but please make them zero as I have shown above.
Ok so you will now tune the P and D terms. Perform the “Tuning the D and P gain” step in the Wiki. As it says tune the D gain first. Increase the gain until it starts to shake( oscillate). Note the value of the D gain. Then set the TUNE param to zero and then set the pitch and roll D gain to half the value noted.
Now do the same thing in for the P gain.
Post the logs for these flights so I can see how it looks.
Just to make sure I am doing it right, for WIKI it says ;
start with D gain, use the tuning future of Arducopter which is linked to Ch6 ( I didn’t setup CH6 to respond to anything in my radio!) but I can assign ch6 to any switch I want!
I have 14sg and it don’t have knob only two sliders on the back!
also Wiki says for D gain . Make the following parameters changes
TUNE = 21
TUNE _LOW= 0
TUNE_HIGH =30*
and then it says ; now tune the P gain . make the following tuning parameters changes
TUNE = 4
TUNE_LOW =0
TUNE_HIGH = 300*
from what I understand is;
make these changes first;
TUNE =0 to 21 (so that will turn on the 21:Rate roll/pitch kD)
TUNE_LOW = 0 to 0
TUNE _HIGH =1000 to 30 ( no need to put * ?)
then go up to the D parameters and start the .001 increment ATC_RAT_RLL_D and
ATC_RAT_PIT_D
example : ATC_RAT_RLL_D .001 and try it till if it shake (oscillation) then cut the value to half ; to .0005)
then do the same thing with ATC_RAT_PIT_D
when I am done from the D
based on wiki ; change the TUNE , LOW and HIGH to ;
TUNE = 4 (so that will turn on 4:rate Roll/pitch kP)
TUNE_LOW =0
TUNE_ HIGH= 300*
and go up to the parameters ATC_RAT_RLL_P and ATC_RAT_PIT_P and start doing the same 0.05 increment till when you get shakes (oscillation) then cut the last value in half and
when you done from all P and D
go down to TUNE and make it 0
and TUNE_LOW = 0
TUNE_HIGH= 1000
you’ll use the slider to do this. Its nice to have it on the slider as you don’t have to keep going and changing it in mission planner. It is right on your transmitter. Plus if you do start seeing bad oscillations you can decrease the value to make it stop. You just have to judge how much change on your slider equates to 0.001 increment in D.
If you use the slider then it will do both at the same time. There are separate TUNE values that let you do each separately
I normally go up in 0.01 increments. 0.05 increments is probably too much at one time.
yes. But remember that you have to change TUNE parameter to zero before you set the value you determined from testing. If you don’t then the transmitter slider will override the value you set. You want to do this for D and P gains.