diff --git a/robots/b1_description/urdf/b1.urdf b/robots/b1_description/urdf/b1.urdf
index 49a448e5aa0c45a4ae1dc46c02116e8cbe56485e..5f91ffe24ca31d95d05d281162497f02f02df03b 100644
--- a/robots/b1_description/urdf/b1.urdf
+++ b/robots/b1_description/urdf/b1.urdf
@@ -291,6 +291,10 @@
         </joint>
     </xacro:if>  -->
   <link name="base">
+    <inertial>
+      <mass value="1e-6"/>
+      <inertia ixx="1e-6" ixy="1e-6" ixz="1e-6" iyy="1e-6" iyz="1e-6" izz="1e-6"/>
+    </inertial>
     <visual>
       <origin rpy="0 0 0" xyz="0 0 0"/>
       <geometry>
diff --git a/robots/go1_description/urdf/go1.urdf b/robots/go1_description/urdf/go1.urdf
index 17ecaf66abe6346defdaaac8ae94e17f7b2f72f6..921a4a17850556870160a7156c714fa235608f7c 100644
--- a/robots/go1_description/urdf/go1.urdf
+++ b/robots/go1_description/urdf/go1.urdf
@@ -405,6 +405,10 @@
         </joint>
     </xacro:if>  -->
   <link name="base">
+    <inertial>
+      <mass value="1e-6"/>
+      <inertia ixx="1e-6" ixy="1e-6" ixz="1e-6" iyy="1e-6" iyz="1e-6" izz="1e-6"/>
+    </inertial>
     <visual>
       <origin rpy="0 0 0" xyz="0 0 0"/>
       <geometry>