Servers by jDrones

Gremsy Pixy U Ardupilot Serial Connection

The Gremsy Pixy U Gimbal has a Pixhawk serial connection which is designed to allow control of the gimbals Pitch, Roll, Yaw and Gimbals Mode (Follow/Hold/Motors On-Off) channels.
While the Pitch, Roll, Yaw channels work the Mode does not and the gimbal is stuck in Hold Mode.
Gremsy have said this due to an Ardupilot coding issue and they are working with the developers to get a fix.
Could someone update me if this issue will be resolved in the near future?

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Hi @Peterarnold,

So yes, I’ve also been chatting with the people at Gremsy and they told me about this issue and I’m planning on a fix for Copter-4.0.x (not sure which point release it will go into).

I’m glad you’re here so I can directly ask you about the details. I’m wondering a bit about where these gimbal modes (Follow, Hold, Motors On/off) are showing up. I normally use MP and I see a different set of available modes.

In any case, I think there are at least two things we need to fix/enhance in AP:

  • Add an auxiliary switch option to allow the user to return the gimbal to “RC Targeting” (i.e. where some of the transmitter inputs control the gimbal)
  • Add a new mode that allows the user to specify that the yaw control is relative to the vehicle. At the moment with a 3-axis gimbal (including the Pixy U) I think once the user is controlling the angles of the gimbal the yaw is always earth-frame. This means that if the vehicle rotates the gimbal rotates in the opposite direction so that it keeps pointing at the same object on the ground (or wherever), in ArduPilot speak we call this “earth frame”. I’m thinking we should add another mode so the gimbal’s heading would rotate with the vehicle’s heading. For reference in AP we call this “body frame”.

What do you think?

Thanks for following up with this!
I think your suggestions are good and you are in a far better position than me know the best way to address this.
For me and reading the Gremsy Pixy U manual I thought I could use a serial connection (cable provided) to connect the Pixy U to a Cube then after setting up the appropriate RC channel use my Taranis X9D to control the Pixy U Pitch, Roll, Yaw, and Modes. Each of which would be on a separate channel. The Taranis slider switches worked with the Pitch, Roll, and Yaw channels. The mode channel was assigned to a 3 position switch. The modes are High (2012) - Follow mode, Middle (1500) - Lock Mode, Low (988) - Motors off. This 3 position switch did not work and the gimbal stays in the middle or Lock mode and is the problem.
I bypassed the Cube with a SBUS connection direct from the RX to the gimbal’s SBUS input and the 3 position switch works and the modes can be changed.
I’m not sure if the above helps but obviously the 3 position switch value is not getting through. I have the Flight Modes on a 6 position switch and maybe something similar that is user defined and can be assigned to a channel could be helpful?

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