Evaluating Webots

I’m trying to find a better simulator than Breve for robots and 3D physics world creation.

I have been examining the Webots simulation environment. It seems pretty useful since I could write controllers in C++ and it comes with several robot models out of the box. And I like the scene graph (or “scene tree” as they call it) approach for environments (they use VRML97 which is obsolete but at least it’s a well known standard); I only played with the interface enough to add a sphere and a box but it seems good enough so far. A lot easier than doing it completely programmatically and/or completely from scratch with raw data files. And I have made 3D models from scratch with data files in the past and it was not that efficient (compared to some ideal GUI) except for tweaking exact numbers.

They have some Nao (aka “NAO”) robot models and it would be awesome to use that for some mental development research. I’m thinking about affordances, and certainly the Nao with its 25 DOF and lots of sensors is more than sufficient for interesting affordances with real world (or simulated 3D world) environments. It may actually be overkill…

simulated Nao looks at a brick box

simulated Nao looks at a brick box

Not that I have access to a real Nao, although I programmed two little little test scripts last year on an actual Nao using Choregraphe, a primarily visual programming tool. Webots can run a Nao server so you can actually hook Choregraphe to the Webots simulation (Choreograph has a sim but just of the robot model, not of environmental interactions). Unfortunately I couldn’t try this out as it’s blocked for free users (the screenshot below shows an attempt to use the robot soccer world).

naoqisim denied!

naoqisim denied!

And I just realized if I write a Webots Nao controller, there’s no documentation or obvious way that I can see to know what the exact actuator names are to pass to wb_robot_get_device() and the demo doesn’t show all motors (or maybe they haven’t implemented all motors?). [Update: I have been informed that you can get the device tags from the Robot Window which can be made visible with the menu (Robot -> Show Robot Window) or double-clicking on the robot in the sim view. Not as good as a text list but at least the info is there.] Making motion files manually would be a pain as well. Maybe I will end up making a simpler robot model from scratch.

The lack of access to the Superviser is also making me question using this for my non-funded research. I might try running some experiments in it, and just see how far I can go without a Superviser.

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