Vectored thrust for overactuated surface vessels - Insights soughts on feasability

ArduRover ArduBoat
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Hi there, I am a researcher that wants to apply PX4 on a boat equipped with vectored thrusters (thrusters with servo unit to produce thurst in any 2D orientation) to make the boat fully/over - actuated in the XY plane.

I have see that nowadays with vectored thrust feature it is somehow possible but i wanted to be sure and to have feedback from the community / devs on the feasibility of this. From what I have seen, it doesn’t seem that one can send independently a thrust in a given direction. Thrust and thrust direction seem to be dependant, am i right or wrong ?

Best regards !

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You may have better luck asking this question in the PX4 forum.
ArduPilot and PX4 are entirely different types of Firmware.

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Hi @fmukwege,

Because you mention Vectored Thrust you probably are talking about using ArduPilot but you’re mixing up hardware with software. Many people mixup “Pixhawk” with “PX4”.

As @Janno says, “PX4” is software (a competitor to ArduPilot) while the Pixhawk is autopilot hardware but AP supports many other autopilots as well.

As mentioned above AP supports Vectored Thrust meaning that it handles a frame where the steering and thrust are combined. AP also support omni style boats where there are three or 4 thrusters pointed in different directions.

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Dear all,

I might have forgot to specify that I was indeed planning on using the PIXHAWK with Ardupilot. Sorry for that.

So to be sure : Vectored Thrust doesn’t allow to control independently the servo angle and the thrust ? To implement such applications, I should towards the Omni configuration right ?

Thank you for your insights

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Hi @fmukwege,

Yes, I think what you’re saying is correct. The steering servo controls the direction of the thrust.

Put another way, I guess you want a vehicle that can move in any direction without changing its heading? In this case you’ll definitely want an omni vehicle. I should mention though that we don’t current support using an omni vehicle’s lateral thrusters in Auto mode… so the vehicle will still turn in order to stay on the line between waypoints. There’s an item somewhere on the to-do list to add this enhancement.

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I am also very interested in using mutiple (3 or 4) vectored propellers (“Schottel”) to steer a vessel and to have a “position hold” dynamic positioning feature.

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Hi @rmackay9, a “vehicle that can move in any direction without changing its heading” is indeed what you could call an overactuated / fully-actuated system. I will take a look to the documentation, thank you for you help. I will post my advancements in this forum

Best

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Can you have more than one motor AND vectored thrust?

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@labomat,

Yes, it is possible to use multiple steering and throttle types together although it hasn’t been extensively tested.

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