When it takes off in auto mode,the pitch begins to oscillate

ArduPlane Plane 3.3
1

the 3.3 release note said:it can solve the problem"A number of users had problems with pitch control on auto-takeoff"

but it likely didn’t work on my plane with 3.3.

i found the “nav_pitch_cd” is set to 500 in the beginning of takeoff.

when the plane takes off in auto mode,the pitch begins to Oscillate.

but in FBWA mode the pitch is controlled well. i think it is not the PID’s problem.

can anybody help?

2

I found the script in attitude.cpp

the nav_pitch_cd must be the demand_pitch in the “bin” file.

but i can’t understand the specific script below.(sth about TECS)

float integ7_input = SEB_error * _integGain;
if (_pitch_dem > _PITCHmaxf) 
{
    integ7_input = min(integ7_input, _PITCHmaxf - _pitch_dem);
}
else if (_pitch_dem < _PITCHminf)
{
    integ7_input = max(integ7_input, _PITCHminf - _pitch_dem);
}
_integ7_state = _integ7_state + integ7_input * _DT;