help please 250 quad violently over reacting

[roycruse]

some help needed please

i have constructed a 250 quad from hobbyking parts including their MultiWii 328p and their baby beast motor combo

only using acro mode so far so i presume i would be right in thinking the baro and mag are not used so i dont need to look at those at all at this stage.

quad is very powerfull as i have found out by several cuts and pieces of my fingers now missing.

If i hold it and try to move it in pitch and yaw directions with 30% to 50% throttle it fights back as expected and if i yaw the same but there is a massive increase in lift also when i rotate it by hand in yaw left and right

if i try to fly it - it starts to bounce in ground effect and then if it touches the floor loads of power kicks in and it shoots off...

any ideas - been trying raising and lowering pitch roll and yaw P values in the pids but lowering the yaw P value doesnt seem to tame this behaviour... lowing the pitch and roll just gives me a drunk feeling copter that still just accelerates upwards quickly.

[FengShuiDrone]

some help needed please

i have constructed a 250 quad from hobbyking parts including their MultiWii 328p and their baby beast motor combo

only using acro mode so far so i presume i would be right in thinking the baro and mag are not used so i dont need to look at those at all at this stage.

quad is very powerfull as i have found out by several cuts and pieces of my fingers now missing.

If i hold it and try to move it in pitch and yaw directions with 30% to 50% throttle it fights back as expected and if i yaw the same but there is a massive increase in lift also when i rotate it by hand in yaw left and right

if i try to fly it - it starts to bounce in ground effect and then if it touches the floor loads of power kicks in and it shoots off...

any ideas - been trying raising and lowering pitch roll and yaw P values in the pids but lowering the yaw P value doesnt seem to tame this behaviour... lowing the pitch and roll just gives me a drunk feeling copter that still just accelerates upwards quickly.

I don't know anything about your TX or what your settings are on it. I would suspect, given the tiny amount of info to work with, that you also need to adjust some stuff like most new quad pilots do. You probably need to center up your TX using subtrims and endpoints. Also, in your PID adjustment area, you could have your throttle mid set too low, RC rate set too high, Pitch/Roll rates set too high, Throttle Expo set too low.......all can cause handling issues similar to what you have. Your pitch, Roll, and Yaw P values should be good somewhere from 3.0 to 6.0 with the yaw around one point higher than the Pitch and Roll. These settings affect flight stability in mostly subtle ways. If your craft wobbles in flight or toilet bowls while hovering you probably have PID value problems. Sounds like your sensors all work properly from what you described. I can only wonder if your motors speeding up in reaction to your yaw test is just the mag or something trying to counter the spin you are giving it. Sorry to hear about your injuries. Be more careful when your props are on. If you are new to this I would recommend a softer hand on the throttle. Contrary to what the media would have you believe, it takes quite a bit of skill to pilot a quadcopter in acro mode. Take baby steps at first....baby steps.

[roycruse]

Hi, thanks for your response.

I have several helis without FCs and a 450 quad and 720 hex one with APM and the other with pixhawk FCs.

I fully understand what a multirotor should feel like in acro mode. And this is definately not a situation of over sensitive stick inputs from a bad rate or expo setting.

My radio is a Spektrum DX9 I have used travel and subtrims to setup the channels to as close as possible to 1000 to 2000 with 1500 centres.

With the quad in acro mode it shouldn't be using the mag or baro sensors if I'm correct ? So should be flying just off of the gyros shouldn't it ?

Holding the quad in my hand with just undernhalf throttle so it's around hovering point if I rotate my wrist so as to yaw the quad left and right there is in addition to the effect of countering the yaw I'm forcing upon the quad a massive increase in overall power trying to yank the quad up out of my hands... It definately doesnt feel right. Unlike any of my other multi rotors.

When trying to fly the quad it takes off for a few seconds can feel the pitch and roll stabilization doing its job then just has a massive surge of power and is gone... Until it hits the ceiling or wall etc...

[FengShuiDrone]

Well, you sounded like a beginner what with the injuries and all.....have you checked the Yaw correction direction in Arduino?
/* NEW: not used anymore for servo coptertypes <== NEEDS FIXING - MOVE TO WIKI */
#define YAW_DIRECTION 1
//#define YAW_DIRECTION -1 // if you want to reverse the yaw correction direction

If yours is set wrong it will do what you describe. Mine was set to #define YAW_DIRECTION -1 instead of the above setup. It throttled up like crazy until I made it right.

[Noctaro]

Hi, which multiwii version do you use?
Did you try to set your D to 0 for roll and pitch?
Greetz

[roycruse]

I think the yaw direction is correct as I can feel it resisting me as I turn but I will reverse it just to be sure. I havnt tried reducing D yet so will give that a go as well... Thanks for the ideas. Will report back later.

Version is 2.4

[Cereal_Killer]

Have you verified all your sensors are defined correctly? Watching the flight gauges in the GUI the AH points up with up pitch, down with down pitch, left with right roll and right with left roll?

You've watched the raw data coming in on the graphs to verify gyro / ACC don't conflict?

[roycruse]

Hi thanks for everyone making suggestions.

I believe my sensors are all working in the correct direction... Here's a video showing the quad being moved about in front of the screen, please let me know if anything is wrong. North is behind me and the quad is facing the screen. https://youtu.be/QvagH2QkBt4

Heres also a video of the problem I've got. Ive only hot about 20% throttle on here not enough to even lift off yet the quad is trying to yank its self upwards out of my hands whilst trying to correct the yaw I'm doing with my hand. https://youtu.be/QXl-sRjHdO8

I really am lost as to what to adjust here and really want to get my quad in the air.

[FengShuiDrone]

Judging by your movements and those of the quad on the GUI you have your pitch and roll reversed. The yaw is correct, but when you pitch the nose up it goes down in the GUI. The north arrow on the GUI is pointing to behind you as well, so when you say the quad is facing the screen, yes, the south side of it is. When you roll right, the quad indicates a left roll, etc. Get your stuff oriented correctly by reversing motor wires or whatever it is that is wrong and I believe your yaw throttle bursts will stop as well.

[Cereal_Killer]

I don't think they look backwards. Seems correct to me. The AH should lean left when the quad banks right, that's how it works IRL (tilt your head to the right, the horizon line moves to the left). Assuming the front of the quad is the side facing the screen and we're looking at the back (and regardless of what direction is what, it doesn't use cardinal directions for flight calculations, only for your info / for waypoint navi).

Maybe my thinking is wrong but the movements shown on that AH and the gauges is the same as on my couple different models and they all fly correctly. That was how it was explained to me but I'm not a real pilot and have never been in a cockpit in flight

[Noctaro]

My octo-x has the same behaviour without dampening. I set D for roll and pitch to 0-10, then it worked......