can not hold in place quadro on HK_MultiWii_328P

This forum is dedicated to all issues and questions related to your individual setups and configurations
Post Reply
Silvar
Posts: 10
Joined: Sun Sep 22, 2013 10:08 am
Location: Moscow

can not hold in place quadro on HK_MultiWii_328P

Post by Silvar »

Hi all.

I have troubles with MultiWii 2.2 on my HK 328P board: I cant hold quadro (plus scheme) in place, it always move.
PID settings looks like correct. In ACRO mode I may not have enough experience, but in LEVEL mode it does not want to stay in place too.

ACC trim looks like fine. Initial state: after taking off quadro move forward. Then trimming backward (full throtle + minimum PITCH). Then, after taking off it move backward. Same for ROLL.
There is no wind (indoor tests) during tests.
PITH/ROLL RATE is 0.9, EXPO is 0,95. As I can see, it should minimize role of deviations RC signal from 1500 in middle stick position.
ACC and GYRO oscillation about +/- 4 points (according to GUI).

Do you have any suggestions what's wrong?

scrat
Posts: 925
Joined: Mon Oct 15, 2012 9:47 am
Location: Slovenia

Re: can not hold in place quadro on HK_MultiWii_328P

Post by scrat »

First you must trim your quad level in ACRO mode. Only then use ACC trim.

Silvar
Posts: 10
Joined: Sun Sep 22, 2013 10:08 am
Location: Moscow

Re: can not hold in place quadro on HK_MultiWii_328P

Post by Silvar »

So, first of all I should take quad in place in ACRO mode and only then make ACC calibration and use LEVEL mode Right?
But what is role of ACC trim? May i correct ACC level settings if it is not perfect?

scrat
Posts: 925
Joined: Mon Oct 15, 2012 9:47 am
Location: Slovenia

Re: can not hold in place quadro on HK_MultiWii_328P

Post by scrat »

First of all you must trim your quad in ACRO mode. When quad stays in position in ACRO mode, then land and turn on ANGLE and see where copter want's to drift. Then land and trin ACC with sticks.

Copter must be disarmed. Then throttle to max...and then move roll/pitch stick in desired postition.

Silvar
Posts: 10
Joined: Sun Sep 22, 2013 10:08 am
Location: Moscow

Re: can not hold in place quadro on HK_MultiWii_328P

Post by Silvar »

scrat wrote:then land and turn on ANGLE and see where copter want's to drift. Then land and trin ACC with sticks.

Copter must be disarmed. Then throttle to max...and then move roll/pitch stick in desired postition.

ACC was calibrated when copter stay in place in ACRO mode (it was very difficult, but I did it).
That is my problem.
  1. ANGLE mode on
  2. arm, taking off
  3. I see forward drift
  4. landing, disarm
  5. throttle to max + pith min
  6. taking off
  7. I see backward drift
  8. landing, disarm
  9. throttle to max + pith max
  10. goto 2

I cant understand what should I do to obtain ANGLE mode without any drift.

tovrin
Posts: 705
Joined: Tue Sep 20, 2011 4:08 pm

Re: can not hold in place quadro on HK_MultiWii_328P

Post by tovrin »

also, if you have any vibrations on the FC from the motors or props you will have problems getting ACC to trim properly. reduce all vibrations or add LPF to the code.

Silvar
Posts: 10
Joined: Sun Sep 22, 2013 10:08 am
Location: Moscow

Re: can not hold in place quadro on HK_MultiWii_328P

Post by Silvar »

tovrin wrote:also, if you have any vibrations on the FC from the motors or props you will have problems getting ACC to trim properly. reduce all vibrations or add LPF to the code.

What level of vibrations is critical? I have just +/-4 poins oscilation on acc, according to GUI.

tovrin
Posts: 705
Joined: Tue Sep 20, 2011 4:08 pm

Re: can not hold in place quadro on HK_MultiWii_328P

Post by tovrin »

is that at idle? I'm not sure what is critical, but if you got it down to as little as possible then apply a lpf in the sketch and upload, see if that helps.

Silvar
Posts: 10
Joined: Sun Sep 22, 2013 10:08 am
Location: Moscow

Re: can not hold in place quadro on HK_MultiWii_328P

Post by Silvar »

This vibration level on 40% of power (after it copter whant run away from testing stand).
Thantks. I'll try low pass filters. But i am not shure that it may help. In LEVEL mode copter dont change drift direction.

tovrin
Posts: 705
Joined: Tue Sep 20, 2011 4:08 pm

Re: can not hold in place quadro on HK_MultiWii_328P

Post by tovrin »

when you are trimming your level mode, how long are you holding the sticks in position? i think every 5 seconds counts as 1 degree of adjsutment, or so i remember, someone will likely correct me if im wrong.

Silvar
Posts: 10
Joined: Sun Sep 22, 2013 10:08 am
Location: Moscow

Re: can not hold in place quadro on HK_MultiWii_328P

Post by Silvar »

Just a second. On this board i have blue diode that start flash when changes applied.

tovrin
Posts: 705
Joined: Tue Sep 20, 2011 4:08 pm

Re: can not hold in place quadro on HK_MultiWii_328P

Post by tovrin »

I'm at a loss, hopefully someone else will have an answer.

Silvar
Posts: 10
Joined: Sun Sep 22, 2013 10:08 am
Location: Moscow

Re: can not hold in place quadro on HK_MultiWii_328P

Post by Silvar »

Thanks for attempt. I'll try LPF and tell results.

Silvar
Posts: 10
Joined: Sun Sep 22, 2013 10:08 am
Location: Moscow

Re: can not hold in place quadro on HK_MultiWii_328P

Post by Silvar »

LPF does not take affect.
BMA180 LPF filters placed in sensors.cpp
Default value is

Code: Select all

control = control | (0x00 << 4); // that equal to 10Hz

( :!: in future I'll use binary values because datasheet use binary)
I try

Code: Select all

control = control | (B0011 << 4); //that equal to 75Hz

It not take effect. And finally i try

Code: Select all

control = control | (B0111 << 4);  //that equal 1200Hz.

But with 1200Hz I don't try to fly, because ACC in GUI in idle state (copter disarmed) show oscillations about 30 points (normally it oscillate +/- 1 point).

Next step is new accelerometer. It will be ADXL345 in few weeks... I don't have other ideas...

Andy7
Posts: 129
Joined: Fri Dec 28, 2012 5:09 pm
Location: Oxford, UK
Contact:

Re: can not hold in place quadro on HK_MultiWii_328P

Post by Andy7 »

Something that has been troubling me. The FAQ says first trim quad in acro mode just using the trim on transmitter.
The trouble is that it's easy for my tx to go out of the range that let's me arm/disarm. Is it enough then to just trim my tx using the GUI to get the pitch and roll to 1500?
The trouble is, the trim buttons on my HK6x seem to jump by 3 points each click and I can't get it dead on.
Perhaps that's why I still get drift.

Am I also right in thinking that the trim that you make when landed by pulling throttle max up and pushing pitch/roll does NOT affect flight in acro mode, just stable mode? Cos that'll explain a lot too.

Thanks

Silvar
Posts: 10
Joined: Sun Sep 22, 2013 10:08 am
Location: Moscow

Re: can not hold in place quadro on HK_MultiWii_328P

Post by Silvar »

Andy7 wrote:Something that has been troubling me. The FAQ says first trim quad in acro mode just using the trim on transmitter.
The trouble is that it's easy for my tx to go out of the range that let's me arm/disarm. Is it enough then to just trim my tx using the GUI to get the pitch and roll to 1500?
The trouble is, the trim buttons on my HK6x seem to jump by 3 points each click and I can't get it dead on.
Perhaps that's why I still get drift.

GUI shows values about 1502-1507 for central positions, but I have RATE about 70-90 and EXP about 90-100 for pitch and roll.
Also, i use DEADBAND (as i can remeber it name) configurtion variable.
So, its look like that i have not troubles here.

Am I also right in thinking that the trim that you make when landed by pulling throttle max up and pushing pitch/roll does NOT affect flight in acro mode, just stable mode? Cos that'll explain a lot too.

Right. It is affect just on ANGLE mode.

Andy7
Posts: 129
Joined: Fri Dec 28, 2012 5:09 pm
Location: Oxford, UK
Contact:

Re: can not hold in place quadro on HK_MultiWii_328P

Post by Andy7 »

Okay cool. So i have my pitch and roll trimmed to as near as I can get to 1500 using the GUI and I'm getting drift in acro mode still. My ESCs are balanced as are my props and motors. Vibration is pretty good as seen in the GUI too.
So where do I go from here to get my quad to stop drifting in acro?

It's quite a lot of drift by the way, about a walking speed.

Is it normal to expect to get some drift or should I be aiming for virtually none?

hkubota
Posts: 35
Joined: Wed Sep 05, 2012 2:48 pm

Re: can not hold in place quadro on HK_MultiWii_328P

Post by hkubota »

Andy7 wrote:So where do I go from here to get my quad to stop drifting in acro?

It's quite a lot of drift by the way, about a walking speed.

Is it normal to expect to get some drift or should I be aiming for virtually none?


There is no drift in acro mode. The only thing you can get wrong is that the quad changes orientation if you don't touch the sticks.
That's then a sensor data or PID problem.

Post Reply