Hi,

I am very new to ROS. using ros indigo and gazebo7 on ubuntu 14.04

I've made diffrential drive robot using gazebo tutorial, if I want to move I have to use this command : rostopic pub /cmdvel geometrymsgs/Twist "linear : x:0.1 y:0.0 z:0.0 angular : x:0.0 y:0.0 z:0.0" or keyboard teleop.

how to make robot start moving when simulation starts? without using keyboard teleop and the publish command.

I want to use hokuyo laser range finder. but i don't know how to get the data directly from hokuyo and robot should avoid the obstacle and move in other direction. In which files should I have to make changes?