parallel gazebo simulations to speedup data collection?

[abdelzaro]

Hi, is it possible to parallelize the gazebo simulations to speedup data collection? Would you recommend it?

[reiniscimurs]

Hi. Probably possible in some way, though I have not tried it. I think an easier method is to place multiple robots in the same simulation and roll out the same policy on them, then collect the data in a single replay buffer. This would also add some additional dynamic obstacles (other robots) in the environment. This should help collect more samples in the same time span so you can train more often and the total training time would reduce.

[abdelzaro]

Thanks for the response! I'm trying to add multiple robots to the same map right now. I modified the code and was able to change some of the topics. But right now I'm stuck on changing "/r1/front_laser/scan" to /r2/front_laser/scan. Any tips?

I'm using namespace while starting the file:
ROS_NAMESPACE=r2 python3 train_velodyne_td3.py r2

[reiniscimurs]

I think this will change the namespace of the robot but will not actually spawn a new robot in the scene.
To be honest it has been a very long time since I have done anything with this code so I do not remember anymore what the steps were, but I think all you need is to spawn another robot when launching a file with a different name and the this name should be used in the creation of the sensors and so.
Try including another robot like this but change the r1 to something else (and its spawning location as well).

DRL-robot-navigation/TD3/assets/multi_robot_scenario.launch

Lines 8 to 11 in 017ed12

	<include file="$(find multi_robot_scenario)/launch/pioneer3dx.gazebo.launch">
	<arg name="robot_name" value="r1" />
	<arg name="robot_position" value="-x 0.0 -y 0.0 -z 0.01 -R 0 -P 0 -Y +0.0" />
	</include>

[abdelzaro]

is movebase used for anything? i was able to spawn two robots but the second robot doesn't move and I'm not sure if the issue has to do with movebase.

[reiniscimurs]

No, move_base plays no role here.
To control multiple robots you will need to publish velocities to the second robot as well. In general, to have multiple robot control you need to allow for batch processing and saving of states in this implementation.