From 666e8061cef8ce8444c9260822a1f40403a88221 Mon Sep 17 00:00:00 2001
From: stepanove <stepanove@gmail.com>
Date: Tue, 18 Nov 2025 22:00:38 +0000
Subject: [PATCH 1/3] Make IMU, GPS, pinger and ball shooter joints fixed

---
 vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro | 8 ++------
 vrx_urdf/wamv_gazebo/urdf/components/wamv_gps.xacro     | 6 +-----
 vrx_urdf/wamv_gazebo/urdf/components/wamv_imu.xacro     | 4 +---
 vrx_urdf/wamv_gazebo/urdf/components/wamv_pinger.xacro  | 4 +---
 4 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro b/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro
index 94d8a4448..720bc0cb4 100644
--- a/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro
+++ b/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro
@@ -47,16 +47,12 @@
       </inertial>
     </link>
 
-    <joint name="${namespace}/${name}_base_joint" type="revolute">
-      <axis xyz="0 0 1"/>
-      <limit effort="1000.0" lower="0.0" upper="0" velocity="0"/>
+    <joint name="${namespace}/${name}_base_joint" type="fixed">
       <origin xyz="${x} ${y} ${z}" rpy="0 0 ${yaw}"/>
       <parent link="${namespace}/base_link"/>
       <child link="${namespace}/${name}_base_link"/>
     </joint>
-    <joint name="${namespace}/${name}_launcher_joint" type="revolute">
-      <axis xyz="0 0 1"/>
-      <limit effort="1000.0" lower="0.0" upper="0" velocity="0"/>
+    <joint name="${namespace}/${name}_launcher_joint" type="fixed">
       <origin xyz="-0.0204 0 0.107877" rpy="0 ${pitch} 0"/>
       <parent link="${namespace}/${name}_base_link"/>
       <child link="${namespace}/${name}_launcher_link"/>
diff --git a/vrx_urdf/wamv_gazebo/urdf/components/wamv_gps.xacro b/vrx_urdf/wamv_gazebo/urdf/components/wamv_gps.xacro
index a7abf9903..a335b64ba 100644
--- a/vrx_urdf/wamv_gazebo/urdf/components/wamv_gps.xacro
+++ b/vrx_urdf/wamv_gazebo/urdf/components/wamv_gps.xacro
@@ -26,9 +26,7 @@
 		 iyy="0.006458" iyz="0.0" izz="0.01125"/>
       </inertial>
     </link>
-    <joint name="${namespace}/${name}_joint" type="revolute">
-      <axis xyz="0 0 1"/>
-      <limit effort="1000.0" lower="0.0" upper="0" velocity="0"/>
+    <joint name="${namespace}/${name}_joint" type="fixed">
       <origin xyz="${x} ${y} ${z}" rpy="${R} ${P} ${Y}" />
       <parent link="${namespace}/base_link" />
       <child link="${namespace}/${name}_link" />
@@ -44,5 +42,3 @@
     </gazebo>
   </xacro:macro>
 </robot>
-
-
diff --git a/vrx_urdf/wamv_gazebo/urdf/components/wamv_imu.xacro b/vrx_urdf/wamv_gazebo/urdf/components/wamv_imu.xacro
index 88c948edb..659276dfb 100644
--- a/vrx_urdf/wamv_gazebo/urdf/components/wamv_imu.xacro
+++ b/vrx_urdf/wamv_gazebo/urdf/components/wamv_imu.xacro
@@ -20,9 +20,7 @@
         <inertia ixx="0.00000542" ixy="0.0" ixz="0.0" iyy="0.00002104" iyz="0.0" izz="0.00002604"/>
       </inertial>
     </link>
-    <joint name="${namespace}/${name}_joint" type="revolute">
-      <axis xyz="0 0 1"/>
-      <limit effort="1000.0" lower="0.0" upper="0" velocity="0"/>
+    <joint name="${namespace}/${name}_joint" type="fixed">
       <origin xyz="${x} ${y} ${z}" rpy="${R} ${P} ${Y}"/>
       <parent link="${namespace}/base_link"/>
       <child link="${namespace}/${name}_link"/>
diff --git a/vrx_urdf/wamv_gazebo/urdf/components/wamv_pinger.xacro b/vrx_urdf/wamv_gazebo/urdf/components/wamv_pinger.xacro
index e22fef62d..a34e7ccc0 100644
--- a/vrx_urdf/wamv_gazebo/urdf/components/wamv_pinger.xacro
+++ b/vrx_urdf/wamv_gazebo/urdf/components/wamv_pinger.xacro
@@ -13,9 +13,7 @@
         <inertia ixx="0.00000542" ixy="0.0" ixz="0.0" iyy="0.00002104" iyz="0.0" izz="0.00002604"/>
       </inertial>
     </link>
-    <joint name="${namespace}/${sensor_name}_pinger_joint" type="revolute">
-      <axis xyz="0 0 1"/>
-      <limit effort="1000.0" lower="0.0" upper="0" velocity="0"/>
+    <joint name="${namespace}/${sensor_name}_pinger_joint" type="fixed">
       <origin xyz="0 0 0" rpy="0 0 0" />
       <parent link="${namespace}/base_link"/>
       <child link="${namespace}/${sensor_name}"/>

From dd8796cd9f7bd285d9d4e5448e303852d407d207 Mon Sep 17 00:00:00 2001
From: stepanove <stepanove@gmail.com>
Date: Thu, 18 Dec 2025 12:26:11 +0000
Subject: [PATCH 2/3] Prevent merging of links required by BallShooterPlugin

---
 vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro b/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro
index 720bc0cb4..057fa73a4 100644
--- a/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro
+++ b/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro
@@ -57,7 +57,11 @@
       <parent link="${namespace}/${name}_base_link"/>
       <child link="${namespace}/${name}_launcher_link"/>
     </joint>
-
+    
+    <gazebo reference="${namespace}/${name}_launcher_joint">
+      <preserveFixedJoint>true</preserveFixedJoint>
+    </gazebo>
+    
     <gazebo reference="${namespace}/${name}_base_link">
       <visual>
         <material>

From 966108ecc0f6af4fc4b2f89e603d77f475833185 Mon Sep 17 00:00:00 2001
From: stepanove <stepanove@gmail.com>
Date: Wed, 24 Dec 2025 17:40:52 +0000
Subject: [PATCH 3/3] Prevent fixed joints lumping  for IMU, GPS, pinger and
 ball shooter.

---
 vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro | 7 ++++++-
 vrx_urdf/wamv_gazebo/urdf/components/wamv_gps.xacro     | 5 +++--
 vrx_urdf/wamv_gazebo/urdf/components/wamv_imu.xacro     | 3 +++
 vrx_urdf/wamv_gazebo/urdf/components/wamv_pinger.xacro  | 4 +++-
 4 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro b/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro
index 057fa73a4..17cddc18c 100644
--- a/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro
+++ b/vrx_urdf/wamv_gazebo/urdf/components/ball_shooter.xacro
@@ -52,12 +52,17 @@
       <parent link="${namespace}/base_link"/>
       <child link="${namespace}/${name}_base_link"/>
     </joint>
+
+    <gazebo reference="${namespace}/${name}_base_joint">
+      <preserveFixedJoint>true</preserveFixedJoint>
+    </gazebo>
+
     <joint name="${namespace}/${name}_launcher_joint" type="fixed">
       <origin xyz="-0.0204 0 0.107877" rpy="0 ${pitch} 0"/>
       <parent link="${namespace}/${name}_base_link"/>
       <child link="${namespace}/${name}_launcher_link"/>
     </joint>
-    
+
     <gazebo reference="${namespace}/${name}_launcher_joint">
       <preserveFixedJoint>true</preserveFixedJoint>
     </gazebo>
diff --git a/vrx_urdf/wamv_gazebo/urdf/components/wamv_gps.xacro b/vrx_urdf/wamv_gazebo/urdf/components/wamv_gps.xacro
index a335b64ba..ef8f9d269 100644
--- a/vrx_urdf/wamv_gazebo/urdf/components/wamv_gps.xacro
+++ b/vrx_urdf/wamv_gazebo/urdf/components/wamv_gps.xacro
@@ -31,8 +31,9 @@
       <parent link="${namespace}/base_link" />
       <child link="${namespace}/${name}_link" />
     </joint>
-
-
+    <gazebo reference="${namespace}/${name}_joint">
+      <preserveFixedJoint>true</preserveFixedJoint>
+    </gazebo>
     <gazebo reference="${namespace}/${name}_link">
       <sensor name="navsat" type="navsat">
         <always_on>1</always_on>
diff --git a/vrx_urdf/wamv_gazebo/urdf/components/wamv_imu.xacro b/vrx_urdf/wamv_gazebo/urdf/components/wamv_imu.xacro
index 659276dfb..666df3219 100644
--- a/vrx_urdf/wamv_gazebo/urdf/components/wamv_imu.xacro
+++ b/vrx_urdf/wamv_gazebo/urdf/components/wamv_imu.xacro
@@ -25,6 +25,9 @@
       <parent link="${namespace}/base_link"/>
       <child link="${namespace}/${name}_link"/>
     </joint>
+    <gazebo reference="${namespace}/${name}_joint">
+      <preserveFixedJoint>true</preserveFixedJoint>
+    </gazebo>
     <gazebo reference="${namespace}/${name}_link">
       <sensor type="imu" name="${name}_sensor">
         <update_rate>${update_rate}</update_rate>
diff --git a/vrx_urdf/wamv_gazebo/urdf/components/wamv_pinger.xacro b/vrx_urdf/wamv_gazebo/urdf/components/wamv_pinger.xacro
index a34e7ccc0..da7695878 100644
--- a/vrx_urdf/wamv_gazebo/urdf/components/wamv_pinger.xacro
+++ b/vrx_urdf/wamv_gazebo/urdf/components/wamv_pinger.xacro
@@ -18,7 +18,9 @@
       <parent link="${namespace}/base_link"/>
       <child link="${namespace}/${sensor_name}"/>
     </joint>
-
+    <gazebo reference="${namespace}/${sensor_name}_pinger_joint">
+      <preserveFixedJoint>true</preserveFixedJoint>
+    </gazebo>
     <gazebo>
       <plugin
         filename="libAcousticPingerPlugin.so"