CoppeliaSim forums

Hi,

I am trying to use VREP's OMPL plugin to have a car find a path over a 3d hill. It seems like using the 3d state space is lacking in that I need the state space expansions to have the car be along the ground. To fix this it seems like you need to use simExtOMPL_setValidStateSamplerCallback. Are there any examples to look at? Also below have planned out what I am trying to do. Is this the right way to go about this? Thanks

• To have a simple car model find a path over a hill using VREP's OMPL plugin (API at http://www.coppeliarobotics.com/helpFil ... mplApi.htm)

• To do this, would like to use function simExtOMPL_setValidStateSamplerCallback to change how it samples spaces (sample positions where car is along the surface)

• Also would like some way to implement a cost function. Need some way to say that flatter sections are preferable to steeper ones (was considering editing the sample space to sample less frequently in steep areas and more frequently in flatter areas, but seems like a hack)

• Finally, if all else fails, could rebuild the plugin in programming/v_repExtOMPL, but this seems difficult and the documentation is outdated. (the README.txt instructions fail at step 2 with error message '/usr/bin/python: No module named v_repStubsGen.__main__; 'v_repStubsGen' is a package and cannot be directly executed')

Hello,

your way of doing seems to be correct. You will have to somehow check the distance to the ground in the state validation function. For that, you can check for the minimum distance between the car and the ground (relatively slow), or you can create an inflated model of the car, and check if the inflated model collides with the ground AND the normal model does not collide with the ground.

You can find a state validation callback example here.

Cheers