diff --git a/src/rl_sar/launch/gazebo_a1.launch b/src/rl_sar/launch/gazebo_a1.launch
index ac6ad65..945e701 100644
--- a/src/rl_sar/launch/gazebo_a1.launch
+++ b/src/rl_sar/launch/gazebo_a1.launch
@@ -1,7 +1,7 @@
 <launch>
     <arg name="wname" default="stairs"/>
     <arg name="rname" default="a1"/>
-    <arg name="cfg" default="isaacgym"/>
+    <arg name="cfg" default=""/>
     <param name="robot_name" type="str" value="$(arg rname)"/>
     <param name="config_name" type="str" value="$(arg cfg)"/>
     <param name="ros_namespace" type="str" value="/$(arg rname)_gazebo/"/>
diff --git a/src/rl_sar/launch/gazebo_b2.launch b/src/rl_sar/launch/gazebo_b2.launch
index b4a9a66..eab726d 100644
--- a/src/rl_sar/launch/gazebo_b2.launch
+++ b/src/rl_sar/launch/gazebo_b2.launch
@@ -1,7 +1,7 @@
 <launch>
     <arg name="wname" default="stairs"/>
     <arg name="rname" default="b2"/>
-    <arg name="cfg" default="isaacgym"/>
+    <arg name="cfg" default=""/>
     <param name="robot_name" type="str" value="$(arg rname)"/>
     <param name="config_name" type="str" value="$(arg cfg)"/>
     <param name="ros_namespace" type="str" value="/$(arg rname)_gazebo/"/>
diff --git a/src/rl_sar/launch/gazebo_b2w.launch b/src/rl_sar/launch/gazebo_b2w.launch
index a5e63b5..0e780e9 100644
--- a/src/rl_sar/launch/gazebo_b2w.launch
+++ b/src/rl_sar/launch/gazebo_b2w.launch
@@ -1,7 +1,7 @@
 <launch>
     <arg name="wname" default="stairs"/>
     <arg name="rname" default="b2w"/>
-    <arg name="cfg" default="isaacgym"/>
+    <arg name="cfg" default=""/>
     <param name="robot_name" type="str" value="$(arg rname)"/>
     <param name="config_name" type="str" value="$(arg cfg)"/>
     <param name="ros_namespace" type="str" value="/$(arg rname)_gazebo/"/>
diff --git a/src/rl_sar/launch/gazebo_go2.launch b/src/rl_sar/launch/gazebo_go2.launch
index 23e3033..ebd06ef 100644
--- a/src/rl_sar/launch/gazebo_go2.launch
+++ b/src/rl_sar/launch/gazebo_go2.launch
@@ -1,7 +1,7 @@
 <launch>
     <arg name="wname" default="stairs"/>
     <arg name="rname" default="go2"/>
-    <arg name="cfg" default="himloco"/>
+    <arg name="cfg" default=""/>
     <param name="robot_name" type="str" value="$(arg rname)"/>
     <param name="config_name" type="str" value="$(arg cfg)"/>
     <param name="ros_namespace" type="str" value="/$(arg rname)_gazebo/"/>
diff --git a/src/rl_sar/launch/gazebo_go2w.launch b/src/rl_sar/launch/gazebo_go2w.launch
index 3af5e5c..428fc8f 100644
--- a/src/rl_sar/launch/gazebo_go2w.launch
+++ b/src/rl_sar/launch/gazebo_go2w.launch
@@ -1,7 +1,7 @@
 <launch>
     <arg name="wname" default="stairs"/>
     <arg name="rname" default="go2w"/>
-    <arg name="cfg" default="isaacgym"/>
+    <arg name="cfg" default=""/>
     <param name="robot_name" type="str" value="$(arg rname)"/>
     <param name="config_name" type="str" value="$(arg cfg)"/>
     <param name="ros_namespace" type="str" value="/$(arg rname)_gazebo/"/>
diff --git a/src/rl_sar/launch/gazebo_gr1t1.launch b/src/rl_sar/launch/gazebo_gr1t1.launch
index 78981f7..99c4ff6 100644
--- a/src/rl_sar/launch/gazebo_gr1t1.launch
+++ b/src/rl_sar/launch/gazebo_gr1t1.launch
@@ -1,7 +1,7 @@
 <launch>
     <arg name="wname" default="stairs"/>
     <arg name="rname" default="gr1t1"/>
-    <arg name="cfg" default="isaacgym"/>
+    <arg name="cfg" default=""/>
     <param name="robot_name" type="str" value="$(arg rname)"/>
     <param name="config_name" type="str" value="$(arg cfg)"/>
     <param name="ros_namespace" type="str" value="/$(arg rname)_gazebo/"/>
diff --git a/src/rl_sar/launch/gazebo_gr1t2.launch b/src/rl_sar/launch/gazebo_gr1t2.launch
index b57ab4a..0fdebb8 100644
--- a/src/rl_sar/launch/gazebo_gr1t2.launch
+++ b/src/rl_sar/launch/gazebo_gr1t2.launch
@@ -1,7 +1,7 @@
 <launch>
     <arg name="wname" default="stairs"/>
     <arg name="rname" default="gr1t2"/>
-    <arg name="cfg" default="isaacgym"/>
+    <arg name="cfg" default=""/>
     <param name="robot_name" type="str" value="$(arg rname)"/>
     <param name="config_name" type="str" value="$(arg cfg)"/>
     <param name="ros_namespace" type="str" value="/$(arg rname)_gazebo/"/>
diff --git a/src/rl_sar/launch/gazebo_l4w4.launch b/src/rl_sar/launch/gazebo_l4w4.launch
index 65a8389..4f9bc74 100644
--- a/src/rl_sar/launch/gazebo_l4w4.launch
+++ b/src/rl_sar/launch/gazebo_l4w4.launch
@@ -1,7 +1,7 @@
 <launch>
     <arg name="wname" default="stairs"/>
     <arg name="rname" default="l4w4"/>
-    <arg name="cfg" default="isaacgym"/>
+    <arg name="cfg" default=""/>
     <param name="robot_name" type="str" value="$(arg rname)"/>
     <param name="config_name" type="str" value="$(arg cfg)"/>
     <param name="ros_namespace" type="str" value="/$(arg rname)_gazebo/"/>
diff --git a/src/rl_sar/src/rl_sim.cpp b/src/rl_sar/src/rl_sim.cpp
index 7e564a1..c70cf18 100644
--- a/src/rl_sar/src/rl_sim.cpp
+++ b/src/rl_sar/src/rl_sim.cpp
@@ -15,6 +15,12 @@ RL_Sim::RL_Sim()
     // read params from yaml
     nh.param<std::string>("robot_name", this->robot_name, "");
     nh.param<std::string>("config_name", this->config_name, "");
+    if (this->config_name.empty())
+    {
+        std::cerr << LOGGER::ERROR << "Configuration file not specified. Please provide it using 'cfg:=xxx'" << std::endl
+                  << LOGGER::ERROR << "Example: roslaunch rl_sar gazebo_<ROBOT>.launch cfg:=<CONFIG>" << std::endl;
+        std::abort();  // Abnormally terminate the program (triggers SIGABRT)
+    }
     std::string robot_path = this->robot_name + "/" + this->config_name;
     this->ReadYaml(robot_path);
     for (std::string &observation : this->params.observations)