Moving this comment to its own topic.
I got a motorized arm（BluePrintLab）, which has three degrees of freedom. How can I integrate it into Pixhawk?
If anyone has any way to help me, I would be very grateful
This post indicates that BluePrint manipulators should be compatible with the BlueROV2 companion computer, and possibly controllable from QGroundControl as well.
I had a look on their website and they don’t seem to post specifics of the API or signals used to control their manipulators, but they do mention they provide “Responsive Integration Support”, so I’d suggest you contact them directly at email@example.com and ask about interfacing with BlueROV electronics. They’ll no doubt be happy to help you get your manipulator up and running
It would be interesting and useful if you can post a follow-up here afterwards for others looking to do something similar later on
OK, I’ll have a try in the way you provide, and if there’s any progress, I’ll share it to here again,