I have no idea how to move my robot in gazebo
I build my robot use urdf.
when i was import it in rviz, it was spawn rightly.
after i fixed my urdf file, and import it in gazebo, i can see my model is stand right like image
but if I click the 'play button' for move my model's joint. my robot is just fall down like this
I don't know what should I do please help me!!
Is it wrong in my urdf file? or other reason?