OpenROV support > 3 thrusters?


#1

Does OpenROV support control of more than 3 thrusters? Looking at the main control board schematics it appears that it doesn’t. Can anyone confirm? Thanks.


#2

Looking at the 2.7 controller board specs it looks like it can control up to 6 servos or ESC’s. Is that 6 servos in addition to the 3 ESC’s that are mounted on the board? (I’m guessing it isn’t and that there are a total of 6 control channels.)

If I use external ESC’s, can I then use up to 6 thrusters?

I’m thinking of possibly using 4 and up to as many as 6 thrusters in my design. If I used 6 I wouldn’t have any servo controls for the camera tilt, so I may limit the design to 4 or 5 thrusters.

I’m guessing that if I used more than 3 thrusters I would have to re-write the control firmware / software in order to control them, correct?


#3

Yes, you will need to modify the Arduino code in the processor on the control board, plus potentially write JavaScript software as well to add whatever extra user-interface channel is necessary.

You’re not the first person looking to do this, so I suspect that within a few software releases there will be something in the stock software for this.

-W


#4

Thanks Walt! Can’t wait to start working on this. :slight_smile:


#5

Another thing I’m trying to learn that will effect whether I’m able to add more thrusters to this design is how the OpenROV electronics handle powering the thrusters. At present the main electronics board is populated with 3 ESC’s that connect to 3 of the servo connections and the motor leads go through the 25 pin connector and out of the housing to the motors.

If I add more motors I will have to add ESC’s for those motors. That shouldn’t be a problem if I keep the ESC’s external to the main electronics hull/housing (I can use Blue Robotics ESC’s or pot the ESC’s to waterproof them.

But what I don’t know (and am hoping someone can tell me) is how does the OpenROV “power down” the ESC’s / motors? Is there a switching mechanism on the control board? If so, I will need to find a way to turn off the power to my extra thrusters. If not, how do you safely power down an OpenROV, by removing the batteries?


#6

So yes, the Atmega firmware controls a switch that powers the ESCs. There is an improvement request for the next rev of the controller board to make that switch easy to access for additional ESCs:
https://github.com/OpenROV/openrov-electronics/issues/25

In the meantime, I’ll have to defer to the Electronics guys on how to best get to the existing switch or otherwise extend a similar power control over the additional ESCs.