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ethz-asl / rotors_simulator

RotorS is a UAV gazebo simulator
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Quadrotors sharing paylod #387

Open PedroHRPBS opened 7 years ago

PedroHRPBS commented 7 years ago

Hello, guys

I have a project to develop where I have 2 quads connected with a bar.

https://ibb.co/efGc3v

In the image above you can see the project illustrated using 1 quad as an example. I'm having a lot of trouble trying to implement this using Hector_quadrotor, so I tought about switching to this simulator. The main issues that I had was to make the spherical joint between the quad and the bar, and also having control of the two aircrafts at the same time. First because it uses URDF which doesn't implement spherical joints and also because having control of two quads in the same model requires some Plugin editing that I don't know how to do.

Anyone has any idea if I can solve these problems with this sim?

Thanks in advance!

ffurrer commented 7 years ago

@fmina has worked on similar problems. So just pinging him here, he might be able to give you some hints.

(and it is definitely possible to simulate this ;))

fmina commented 7 years ago

To create a spherical joint you will have to combine three revolute joints. Controlling two MAVs doesn't need any modification of the plugins. You just have to use correct namespace for each MAV, for example firefly1 and firefly2.

PedroHRPBS commented 7 years ago

But then, how do I add the bar to connect them? Changing the namespace is done on the .launch file, right? Is it possible to create joints there?

fmina commented 7 years ago

No, two MAVs connected with one object is seen by gazebo as single robot. You need to prepare a urdf file that creates the mechanics of two MAVs and connect them with joints and links. The MAV mechanics is defined here: https://github.com/ethz-asl/rotors_simulator/blob/master/rotors_description/urdf/firefly.xacro

PedroHRPBS commented 7 years ago

So, to have a "robot" that constains 2 quads, I would have to instantiate 2 quads inside of this file that you sent? I want that the two quads fly independently.

juanmed commented 5 years ago

@PedroHRPBS Hi. I see this thread has been around for a long time. Did you by any chance get to work this around? Joining two quads with a bar? If yes, would you mind pointing to any examples on how you got it working? Thanks!

PedroHRPBS commented 5 years ago

@juanmed actually I gave up, this was a project that I was working on at my graduation. But it took another path, so I didn't end up solving this. Sorry.

juanmed commented 5 years ago

I see. Thanks for your answer!