diff --git a/urdf/leg.xacro b/urdf/leg.xacro
index 8d14818..9f2ade1 100644
--- a/urdf/leg.xacro
+++ b/urdf/leg.xacro
@@ -24,6 +24,11 @@
    <xacro:property name="phalange_height" value="0.0745" />
  <xacro:property name="phalange_width" value="0.020" />
  <xacro:property name="phalange_large" value="0.020" />
+   <!-- Friction model from "Characterization and modeling of a Dynamixel servo" by Arno Mensin (model AX12, better than nothing) -->
+  <!-- Damping N.m.s/rad --> 
+  <xacro:property name="dxl_damping" value="0.15" />
+  <!-- Friccion N.m -->
+  <xacro:property name="dxl_friction" value="0.3" />
   <xacro:macro name="cuboid_inertia_def" params="x y z mass">
     <inertia 
       iyy="${mass*(z*z+x*x)/12.0}"
@@ -159,20 +164,22 @@
     </collision>
   </link>
   
-  <joint name="${side}_pelvis_joint" type="revolute">
+  <joint name="${side}_pelvis_joint" type="fixed">
     <parent link="${parent}"/>
     <child link="${side}_pelvis"/>
     <origin xyz="${-body_large/6} ${reflect*body_width/2} ${body_height/5}" rpy="0 0 0" />
     <axis xyz="0 0 1" />
-    <limit effort="4" velocity="1" lower="0" upper="0.01" />
+    <!--limit effort="1" velocity="4" lower="0" upper="0.01" /-->
+    <!--dynamics damping="${dxl_damping}" friction="${dxl_friction}" /-->
   </joint>
   
-  <joint name="${side}_thigh_yaw_joint" type="revolute">
+  <joint name="${side}_thigh_yaw_joint" type="fixed">
     <parent link="${side}_pelvis"/>
     <child link="${side}_thigh_yaw"/>
     <origin xyz="0 ${reflect*pelvis_width/2} ${-1*pelvis_height}" rpy="0 0 0" />
     <axis xyz="0 0 1" />
-    <limit effort="4" velocity="1" lower="0" upper="0.01" />
+    <!--limit effort="1" velocity="4" lower="0" upper="0.01" /-->
+    <!--dynamics damping="${dxl_damping}" friction="${dxl_friction}" /-->
   </joint>
 
   <joint name="${side}_thigh_pitch_joint" type="revolute">
@@ -180,7 +187,8 @@
     <child link="${side}_thigh"/>
     <origin xyz="0 0 0" rpy="0 0 0" />
     <axis xyz="0 1 0" />
-    <limit effort="4" velocity="1" lower="${-75*M_PI/180}" upper="${45*M_PI/180}"  />
+    <limit effort="1" velocity="4" lower="${-75*M_PI/180}" upper="${45*M_PI/180}"  />
+    <!--dynamics damping="${dxl_damping}" friction="${dxl_friction}" /-->
   </joint>
 
   <joint name="${side}_tibia_joint" type="revolute">
@@ -188,7 +196,8 @@
     <child link="${side}_tibia"/>
     <origin xyz="0 0 ${-1*thigh_height}" rpy="0 0 0" />
     <axis xyz="0 1 0" />
-    <limit effort="4" velocity="1" lower="${0*M_PI/180}" upper="${150*M_PI/180}" />
+    <limit effort="1" velocity="4" lower="${0*M_PI/180}" upper="${150*M_PI/180}" />
+    <!--dynamics damping="${dxl_damping}" friction="${dxl_friction}" /-->
   </joint>
 
   <joint name="${side}_ankle_joint" type="revolute">
@@ -196,7 +205,8 @@
     <child link="${side}_ankle"/>
     <origin xyz="0 0 ${-1*tibia_height}" rpy="0 0 0" />
     <axis xyz="0 1 0" />
-    <limit effort="4" velocity="1" lower="${-90*M_PI/180}" upper="${0*M_PI/180}" />
+    <limit effort="1" velocity="4" lower="${-90*M_PI/180}" upper="${0*M_PI/180}" />
+    <!--dynamics damping="${dxl_damping}" friction="${dxl_friction}" /-->
   </joint>
 
   <joint name="${side}_phalange_joint" type="revolute">
@@ -204,7 +214,8 @@
     <child link="${side}_phalange"/>
     <origin xyz="0 0 ${-1*ankle_height}" rpy="0 0 0" />
     <axis xyz="0 1 0" />
-    <limit effort="4" velocity="1" lower="${-45*M_PI/180}" upper="0" />
+    <limit effort="1" velocity="4" lower="${-45*M_PI/180}" upper="0" />
+    <!--dynamics damping="${dxl_damping}" friction="${dxl_friction}" /-->
   </joint>
 </xacro:macro>
 </robot>
\ No newline at end of file
diff --git a/urdf/structure.xacro b/urdf/structure.xacro
index 9cc6bed..f02ee2c 100644
--- a/urdf/structure.xacro
+++ b/urdf/structure.xacro
@@ -31,18 +31,18 @@
     <child link="${child}"/>
     <origin xyz="0 0 ${-support_height}" rpy="0 0 0" />
   </joint>
-  <joint name="beam_to_slider" type="prismatic">
+  <joint name="beam_to_slider" type="fixed">
     <parent link="beam"/>
     <child link="slider"/>
-    <origin xyz="0 0 ${-1*cross_length}" rpy="0 0 ${90*M_PI/180}" />
+    <origin xyz="0 0 ${-1*cross_length}" rpy="0 0 ${90*M_PI/180}"/>
     <axis xyz="1 0 0" />
-    <limit effort="3" velocity="2" lower="5" upper="20" />  
+    <!--limit effort="3" velocity="2" lower="5" upper="20" /-->  
   </joint>
   <link name="column">
     <inertial>
       <origin xyz="0 0 0" />
-      <mass value="1"/>
-      <xacro:cuboid_inertia_def x="${cross_length}" y="${cross_length}" z="${column_height}" mass="10"/>
+      <mass value="3"/>
+      <xacro:cuboid_inertia_def x="${cross_length}" y="${cross_length}" z="${column_height}" mass="3"/>
     </inertial>
     <visual>
       <!--origin xyz="-0.0235 0 -0.03525" rpy="0 0 0" /-->
@@ -61,8 +61,8 @@
     <link name="slider">
     <inertial>
       <origin xyz="0 0 0" />
-      <mass value="10"/>
-      <xacro:cuboid_inertia_def x="${cross_length}" y="${cross_length}" z="${cross_length}" mass="10"/>
+      <mass value="0.1"/>
+      <xacro:cuboid_inertia_def x="${cross_length}" y="${cross_length}" z="${cross_length}" mass="0.1"/>
     </inertial>
     <visual>
       <origin xyz="0 0 0" rpy="0 0 0" />
@@ -78,9 +78,9 @@
   </link>
     <link name="support">
     <inertial>
-      <origin xyz="0 0 ${-1*support_height/2}" />
-      <mass value="10"/>
-      <xacro:cuboid_inertia_def x="${cross_length}" y="${cross_length}" z="${support_height}" mass="10"/>
+      <origin xyz="0 0 0" />
+      <mass value="0.4"/>
+      <xacro:cuboid_inertia_def x="${cross_length}" y="${cross_length}" z="${support_height}" mass="0.4"/>
     </inertial>
     <visual>
       <origin xyz="0 0 ${-1*support_height/2}" rpy="0 0 0" />
@@ -98,8 +98,8 @@
     <link name="beam">
     <inertial>
       <origin xyz="0 ${beam_height/2} 0" />
-      <mass value="2"/>
-      <xacro:cuboid_inertia_def x="${cross_length}" y="${beam_height}" z="${cross_length}" mass="10"/>
+      <mass value="8"/>
+      <xacro:cuboid_inertia_def x="${cross_length}" y="${beam_height}" z="${cross_length}" mass="8"/>
     </inertial>
     <visual>
       <!--origin xyz="-0.0235 0 -0.03525" rpy="0 0 0" /-->