Gimbal plugin implementation idea

[AlexisTM]

In the gimbal implementation, why isn't the roll implemented while it is available in the MAVLink message?

develop@/plugins/gimbal/gimbal_impl.cpp

Couldn't it be a better to use individual getter and setters for the gimbal, keeping in memory the command to apply?

void GimbalImpl::set_yaw(float yaw_deg)
{
yaw = yaw_deg;
}
void GimbalImpl::set_pitch(float pitch_deg)
{
pitch = pitch_deg;
}
void GimbalImpl::set_roll(float roll_deg)
{
roll = roll_deg;
}
void GimbalImpl::set_pitch_yaw_roll(float yaw_deg, float pitch_deg, float roll_deg)
{
roll = roll_deg;
pitch = pitch_deg;
yaw = yaw_deg;
}

And an apply function:

Gimbal::Result GimbalImpl::apply()
{
MAVLinkCommands::CommandLong command{};

command.command = MAV_CMD_DO_MOUNT_CONTROL;
command.params.param1 = pitch;
command.params.param2 = roll;
command.params.param3 = yaw;
command.params.param7 = float(MAV_MOUNT_MODE_MAVLINK_TARGETING);
command.target_component_id = _parent->get_autopilot_id();

return gimbal_result_from_command_result(_parent->send_command(command));
}
Gimbal::Result GimbalImpl::apply_async() { ... }

[julianoes]

Do you have a use case where you need to set roll? I'm interested to hear about it, normally a gimbal just stabilizes roll.

[AlexisTM]

@julianoes I don't have one personally, that's a very good point.

The feature I miss is to control the zoom (such as Peeper T10x) or shutter for other cameras.

NOTE: Is it possible to control an SBUS gimbal using MAVLink?

[julianoes]

Hehe, see 😄 .

Zoom is something we don't have a mavlink spec for yet, that's indeed something missing.

NOTE: Is it possible to control an SBUS gimbal using MAVLink?

If the autopilot had a driver implemented for it, yes.

[AlexisTM]

On top of that, I am using the Offboard mode (PX4 1.8.0+)

[julianoes]

No one else has asked for roll, so I'm closing this.

[Daybreakerflint]

Why would this be needed?

• Our drone system will be mounted with a dual polarized antenna (Horizontal/Vertical). To test the effects of missaligment to the target, one should be able to set the roll of the antenna.
• In the cases where two axis are switched, as in my case where I am only able to control yaw and roll, it would be nice to have a workaround to set all three angles.

Implementation idea

• Setting the quaterion directly
• A function to set pitch, yaw and roll angle

My situation
I connected my gimbal (Gremsy Pixy U) to my flight controller (Pixhawk 6x) and I want to control exactly where the gimbal is pointing to. In the final version I think ROI will be used but for testing all the functions of the system attached, manual settings will be used.

I am also facing the problem that my pitch and roll angle are switched. So if I set a pitch angle, the roll is set on the gimbal. I have not yet found where the issue is.
Edit: The error was in the mounting. I had the system facing the wrong way. For those who stumble across this. Check on where the gimbal is pointing to.

Cheers.