below is a link for my quadcopter simulation.

http://youtu.be/8xYpy0YkA-c

my pid value for the roll and pitch is p=0.7,i=0,d=0.1 while for yaw is p=0.2,i=0,d=0.

can anyone advice me on why my quadcopter can't stabilise and keep spinning in a cw direction and tend to drift away from the starting point.

is it because my pid value is wrong?

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If you are a mathematician, the P is Proportion, D is Differencial, and I is Integral ... and these will all have instant meaning to you.  But if you are not:

Think of P as being the Power of the response.

Think of D as being the raDar that watches how close the correction is getting to target and making an appropriate response.

Think of I as being Intelligence remembering the long term

So the existing yaw settings have no raDar and no Intellegence, just a little power and maybe not enough.

If changing the PIDs for yaw do not correct well enough then you may:

o have a bent motor mast

o have a loose motor mast bolt

o have a loose or tilted motor mount

o incorrect rotor spin (you can tell this by applying Yaw and watching which motor spin up and down)

hi, i have added value to i and d. my quadcopter stop spinning but the quadcopter still tend to drift.

below attach is my angle of att for row, pitch and yaw after 1 min. while my psi and phi is at 0. my theta is not at 0.

why is this so when i use the same value for pitch and row.

my yaw value now is -0.7,0.001 and 0.1

Attachments:

Is your yaw P 0.7 or -0.7?

Drifting is normal in stabilize mode.  Scan the forum for auto trim set and follow those directions.  Basically you trim the pitch/roll sticks so that the copter quits drifting.  Then you tell the APM to remember those settings.

PIDs for pitch and roll should rarely be the same (but most pilots leave them that way because it is close enough).  To be the same, the followings has to be true.

o Pitch motors pairs produce the same thrust per command as the Roll motor pairs (approximately true).

o Pitch motor pairs are the same distance from the x-axis as the Roll motor pairs are from the y-axis (normally true since most multicopter have regular shapes).

o The mass of the copter is equally distributed around the center of gravity (rarely true).

Is your quad symetrical on all axis ? If yes parameters for roll and pitch should remain identical.

Second it is a good rule to have I=P. I see your I is zero which means basically that you do not use the integral part of the pid loop. I is used to compensate for permanent external forces on the quad such as wind for example.

What is the weight of your quad and what props do you use at which KV ?

hi, this problem is already solve, now i have another set of problem. maybe u can help. the link is http://diydrones.com/forum/topics/problem-with-position-control?xg_...

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