AutoTune recommandation - Yaw Issue

ArduCopter Copter 4.5
1

Hello,

Since I am new working with Arducopter or even drones in general, I would really appreciate someones feedback/recommendation and answering on couple of questions that I got from anyone who can support or guide me.

In this post, i will list hardware type that is being used and firmware. Also, I will briefly explain what I did to achieve the current drone flight state that you will see in the logs.

Hardware:
Hexacopter X-Frame
T-Motor 1300KV
ESC T-Motor 40A UBEC
Pixhawk 6X
props: 7x5.5
Battery: 4S 5-Amps
Software:
ArduCopter V4.5.1 (71a2f169)
ChibiOS: 6a85082c (im not sure what this is or if its beneficial to know)
RC Protocol: PPM

I have followed the documentation for initial tuning, then i did AutoTuning for pitch, and then i simply coppied the values from pitch to roll. Then i started to fly and reduce the PID’s by 50% until i noticed that I could not have a smoother response more than what i reached.

My questions and seeking for recommandations:

  • When i fly with stabilize, and input roll or pitch, the response is still fast and I am aiming for a smoother response (meaning, when i input roll/pitch i would like the drone to stabilize itself in a smoother way not jerky way). Any recommendations how could I achieve that?

  • I am facing an issue with Yaw maneuver. The yaw is not nice to use at all, specially during stabilize mode. Lets say i want to turn from 12 to 3 o’clock, when i apply the yaw input the drone achieves 3 o’clock then after 1 second the drone yaw back (towards 12 o’clock)10 degrees. Note that time and amount of degrees can be observed in the logs. How can I get rid of this phenomenon? Also, any recommendations about the PID values for yaw? I have already tried to do autotuning but have never achieved a completion.

  • With the ESC and battery that I am using, can I use a larger propeller size?

  • The next step for me is I would like to add around 1 Kg of payload. Will the drone still be flyable with the current parameter configuration? If not, should I repeat the whole steps that I did from the beginning?

  • In Loiter I could sometime observe a weird phenomenon. The drone starts to move slowly in a circular path and then the speed of the circular motion starts to slightly increase. Note that I could not replicate the behaviour everytime i switch to Loiter. Any ideas?

Thank you so much your help and guidance!

Here are the logs

2

Access denied on the log

3

My bad, i think this one should work.

https://drive.google.com/drive/folders/1ehYt_1w_haLUlCcnhM72n1egL8W38HaJ?usp=sharing

4

“In Loiter I could sometime observe a weird phenomenon. The drone starts to move slowly in a circular path and then the speed of the circular motion starts to slightly increase”

This is usually caused by a bad compass calibration, called the “toilet bowl effect”.

5

And to fix it is to simply do compass a calibration again?

6

Yes. And maybe you have to change compass position or that of other components to get rid of magnetic interference.

7

Okay thank you. I will give it a try then.

I will really appreciate if anyone can answer me on the rest of the questions.

8

Regarding the Compass calibrations Magfit says:

Mag 1 possible incorrect orientation: 0:None
Should be: 6:Yaw270 ?
Cost ratio: 2.47

Other than that I couldnt get a better calibration out of Magfit since you dont seem to have a working voltage or current sensor. That will help enormously and the voltage sensor is ESSENTIAL for safety.

For everything else, adjust these:

ARMING_CHECK,1
ATC_RAT_YAW_I,0.03
ATC_RAT_YAW_P,0.3
ATC_THR_MIX_MAN,0.5
INS_ACCEL_FILTER,10
INS_HNTCH_ATT,40
INS_HNTCH_FM_RAT,0.7
INS_HNTCH_FREQ,120
INS_HNTCH_REF,0.35
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,4
PSC_ACCZ_I,0.8
PSC_ACCZ_P,0.4

The thrust expo is wrong, it should be:
MOT_THST_EXPO,0.54
and you will also have to retest and set:

MOT_SPIN_ARM
MOT_SPIN_MIN

then run Autotune again.

3 Likes
9

I appreciate your help!

I will apply the changes you suggested and test it again when the weather allows for a flight test.

“Other than that I couldnt get a better calibration out of Magfit since you dont seem to have a working voltage or current sensor. That will help enormously and the voltage sensor is ESSENTIAL for safety.”
→
Reply: I might have missed that in the documentation so how can I have the sensor activated to monitor the voltage or current? or more accuratly how should I get them logged?
I think Pixhawk 6X already contain such sensor… please correct me if I’m wrong.

The only hardware that is not listed compared to my original post is this:

10

Just set these to suit that “power brick”
BATT_MONITOR,21
and reboot the flight controller, then you should have these:

BATT_I2C_BUS,1
BATT_I2C_ADDR,0

That should now be working for voltage and current, and logging it. Check in the MissionPlanner HUD for the correct battery voltage.

You will need to check and set EXACTLY these:

BATT_ARM_VOLT,14.70
BATT_CRT_VOLT,14.00
BATT_LOW_VOLT,14.40
BATT_FS_CRT_ACT,1
BATT_FS_LOW_ACT,3
MOT_BAT_VOLT_MAX,16.80
MOT_BAT_VOLT_MIN,13.20
1 Like
11

Thank you again for your support. I will follow your instruction and update the status of my post.

I still have additional questions that are not yet answered, and I’ll be grateful if anyone can give me a bit guidance.
→

  • With the ESC and battery that I am using, can I use a larger propeller size? So that i can get a bit of more lift?
12

It wont be the ESCs that hold you back, I suspect those motors will struggle with more than 7inch props.
You’ll need to go to lower KV, around 1000, but you could try going to 8 inch props and see what happens before you change out anything else.

If you were going to change motors also go for a new ESC too - search on getfpv.com, there’s a 6in1 ESC but it is only BLHELI_S unfortunately (why do they do that??) and there is an 8in1 that’s BLHELI_32.

When you are looking for more upgrades, change out the steam-powered PPM receiver (and maybe transmitter too) for something modern with one of the new serial protocols.

2 Likes
13

The only reason that I want to have bigger prop size is because I am adding a payload.
Currently the drone flies normally with a total weight 2 Kg. Do you think with the current hardware configuration I might have problems flying with an extra 1 Kg of payload?