Motion planning RRTConnect: Unable to sample any valid states for goal tree

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louxibai
Posts: 6
Joined: 10 Oct 2018, 22:36

Motion planning RRTConnect: Unable to sample any valid states for goal tree

Post by louxibai » 11 Apr 2019, 23:25

Hi,

I'm grasping on object from ground, the motion planning returns those error messages in terminal:

Error: RRTConnect: Unable to sample any valid states for goal tree
at line 253 in /home/marc/Documents/ompl-1.4.2-Source/src/ompl/geometric/planners/rrt/src/RRTConnect.cpp
Info: RRTConnect: Created 1 states (1 start + 0 goal)

I thought this means all the goal configs generated by the motion planning script are invalid and are discarded. However, the robot still moves very abruptly to the object and finishes the motion. Could you help me take a look at the scene?

https://www.dropbox.com/s/o4bi1211xpn16 ... 1.ttt?dl=0

Thanks a lot

X.L.

coppelia
Site Admin
Posts: 7157
Joined: 14 Dec 2012, 00:25

Re: Motion planning RRTConnect: Unable to sample any valid states for goal tree

Post by coppelia » 16 Apr 2019, 06:36

Hello,

it is difficult to say what is going on, and we can't debug such a long code. Maybe try with a simpler example first. Make sure that the robot is not colliding in the goal configuration and/or that the goal pose is actually reachable.
If your robot suddenly moves without explicit motion commands (and no dynamics), then this is very probably the inverse kinematics that is trying to bring your end-effector in position (but I see that your IK group is in explicit handling... so it shouldn't move without trigger).

Cheers

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