Rapid climb in drift mode?

ArduCopter Copter 3.1
1

Hi.

I have built a new quad and run 3.1 using V configuration and having a problem with the quad climbing rapidly in drift mode.

The quad is very stable in stabilize, loiter & alt hold. In fact in alt hold and loiter I get no up or down movement and can hover at one altitude for a whole battery if I want.

As soon as I go into drift mode and start moving the quad starts climbing quite fast and I have to back the throttle right down to bring it back down.

I have included a log.
Any ideas what I am missing.

[attachment=0]2014-02-06 14-00.log[/attachment]

2

I assume that nobody has a clue then!

3

It sounds like the documentation is incorrect - the throttle stick is fully manual in drift mode. Expecting it to do alt-hold is the problem.

system.pde:

        case DRIFT:
            success = true;
            set_yaw_mode(YAW_DRIFT);
            set_roll_pitch_mode(ROLL_PITCH_DRIFT);
            set_nav_mode(NAV_NONE);
            set_throttle_mode(THROTTLE_MANUAL_TILT_COMPENSATED);
            break;
4

Ah that would explain it then, I was under the impression that alt hold was still active when in drift mode.

Thanks for the reply.
Andy.

5

Hi,

IMO the documentation is correct it says:

  • The user has completely manual control over the throttle as in Stabilize mode.

  • Pilot’s throttle input controls the average motor speed meaning that constant adjustment of the throttle is required to maintain altitude. If the pilot puts the throttle completely down the motors will go to their minimum rate (MOT_SPIN_ARMED) and if the vehicle is flying it will lose attitude control and tumble.

copter.ardupilot.com/wiki/drift-mode/