Simulation of multiple Husky robots

Hello all, I'm relatively new to ROS and I'm working on simulation of multiple Clearpath Huskies running some simple obstacle avoidance code that I've written. I've installed and used the husky_gazebo package to successfully simulate a single robot with my code, but I'm running into difficulties when I try to add more. The way I'm hoping to accomplish this is through the use of namespaces, but I'm afraid I don't understand them very well. Here is the launch file where I'm attempting to do this: This calls another launch file to actually spawn the vehicle: target_frame: base_link # Leave empty to output scan in the pointcloud frame tolerance: 1.0 min_height: 0.05 max_height: 1.0 angle_min: -0.52 # -30.0*M_PI/180.0 angle_max: 0.52 # 30.0*M_PI/180.0 angle_increment: 0.005 # M_PI/360.0 scan_time: 0.3333 range_min: 0.45 range_max: 4.0 use_inf: true # Concurrency level, affects number of pointclouds queued for processing and number of threads used # 0 : Detect number of cores # 1 : Single threaded # 2->inf : Parallelism level concurrency_level: 0 But when I actually run the code, several errors occur. The first seems to be keeping me from spawning a second model of the same robot. [ERROR] [1454450853.949772124, 1298.480000000]: SpawnModel: Failure - model name mobile_base already exist. And then there are two of these errors: [WARN] [WallTime: 1454450882.509616] [1326.730000] Controller Spawner couldn't find the expected controller_manager ROS interface. Which seem to be a problem that the namespace is causing with the robot controller. I'm just looking for anyone who might be doing similar work who would be willing to share or possibly someone who understands these errors well enough to tell me what they mean. I'll update this question as I figure out more. Thanks!