diff --git a/data/a1/urdf/a1.urdf b/data/a1/urdf/a1.urdf
index 163d3f5..8b8711c 100644
--- a/data/a1/urdf/a1.urdf
+++ b/data/a1/urdf/a1.urdf
@@ -50,7 +50,7 @@
         </joint>
     </xacro:if>  -->
 <link name="world"/>
-  <joint name="floating_base" type="floating">
+  <joint name="" type="floating">
     <origin rpy="0 0 0" xyz="0 0 0"/>
     <parent link="world"/>
     <child link="trunk"/>
diff --git a/data/a1/urdf/a1.xml b/data/a1/urdf/a1.xml
index 9fe4483..4ce5f62 100644
--- a/data/a1/urdf/a1.xml
+++ b/data/a1/urdf/a1.xml
@@ -35,7 +35,7 @@
 
         <body name="trunk" pos="0 0 0.5">
             <inertial pos="0.0127283 0.00218554 0.000514891" quat="0.00186575 0.711506 0.000389649 0.702677" mass="4.714" diaginertia="0.0648213 0.0565803 0.0169323" />
-            <joint name="floating_base" type="free" />
+            <joint type="free" />
             <geom type="mesh" contype="0" conaffinity="0" group="1" rgba="0.913725 0.913725 0.847059 1" mesh="trunk" />
             <geom size="0.1335 0.097 0.057" type="box" rgba="0.913725 0.913725 0.847059 0" />
             <geom size="0.0005 0.0005 0.0005" type="box" contype="0" conaffinity="0" group="1" rgba="0.8 0 0 0" />
diff --git a/data/aliengo/urdf/aliengo.urdf b/data/aliengo/urdf/aliengo.urdf
index 174d3fe..6570326 100644
--- a/data/aliengo/urdf/aliengo.urdf
+++ b/data/aliengo/urdf/aliengo.urdf
@@ -49,7 +49,7 @@
         </joint>
     </xacro:if>  -->
 <link name="world"/>
-  <joint name="floating_base" type="floating">
+  <joint name="" type="floating">
     <origin rpy="0 0 0" xyz="0 0 0"/>
     <parent link="world"/>
     <child link="trunk"/>
diff --git a/data/aliengo/urdf/aliengo.xml b/data/aliengo/urdf/aliengo.xml
index 2b15ab0..12766a5 100644
--- a/data/aliengo/urdf/aliengo.xml
+++ b/data/aliengo/urdf/aliengo.xml
@@ -34,7 +34,7 @@
 
         <body name="trunk" pos="0 0 0.5">
             <inertial pos="0.00846406 0.00404455 -0.000762916" quat="-3.12625e-05 0.708321 0.00247254 0.705886" mass="9.042" diaginertia="0.174706 0.161175 0.033357" />
-            <joint name="floating_base" type="free" />
+            <joint type="free" />
             <geom type="mesh" contype="0" conaffinity="0" group="1" rgba="0.2 0.2 0.2 1" mesh="trunk" />
             <geom size="0.3235 0.075 0.056" type="box" rgba="0.2 0.2 0.2 0" />
             <geom size="0.0005 0.0005 0.0005" type="box" contype="0" conaffinity="0" group="1" rgba="0.8 0 0 0" />
diff --git a/data/laikago/urdf/laikago.urdf b/data/laikago/urdf/laikago.urdf
index 81ad5ed..747a03c 100644
--- a/data/laikago/urdf/laikago.urdf
+++ b/data/laikago/urdf/laikago.urdf
@@ -41,7 +41,7 @@
   </material>
 
   <link name="world"/>
-  <joint name="floating_base" type="floating">
+  <joint name="" type="floating">
       <origin rpy="0 0 0" xyz="0 0 0"/>
       <parent link="world"/>
       <child link="trunk"/>
diff --git a/data/laikago/urdf/laikago.xml b/data/laikago/urdf/laikago.xml
index 34ef537..b901380 100644
--- a/data/laikago/urdf/laikago.xml
+++ b/data/laikago/urdf/laikago.xml
@@ -33,7 +33,7 @@
 
         <body name="trunk" pos="0 0 0.55">
             <inertial pos="0.002284 -4.1e-05 0.025165" quat="-0.00605949 0.710803 -0.00734309 0.703327" mass="13.733" diaginertia="0.254491 0.250684 0.0733281" />
-            <joint name="floating_base" type="free" />
+            <joint type="free" />
             <geom type="mesh" contype="0" conaffinity="0" group="1" rgba="0.2 0.2 0.2 1" mesh="trunk" />
             <geom size="0.2808 0.086 0.09375" pos="0 0 0.01675" type="box" rgba="0.2 0.2 0.2 0" />
             <body name="FR_hip" pos="0.21935 -0.0875 0">
