From d111ea979d79a1da75a58fc65c28122625a96ef5 Mon Sep 17 00:00:00 2001
From: Balduin <mbjd@users.noreply.github.com>
Date: Fri, 7 Mar 2025 14:42:14 +0100
Subject: [PATCH] Add world with moving platform (#83)

New world moving_platform to simulate takeoff/landing on moving vehicle. Depends on MovingPlatformController plugin introduced in https://github.com/PX4/PX4-Autopilot/pull/24471. Launch using:

PX4_GZ_MODEL_POSE=0,0,2.2,0,0,0 PX4_GZ_WORLD=moving_platform make px4_sitl gz_standard_vtol
---
 .gitignore                          |  1 +
 models/moving_platform/model.config |  4 ++
 models/moving_platform/model.sdf    | 48 ++++++++++++++
 worlds/moving_platform.sdf          | 97 +++++++++++++++++++++++++++++
 4 files changed, 150 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 models/moving_platform/model.config
 create mode 100644 models/moving_platform/model.sdf
 create mode 100644 worlds/moving_platform.sdf

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a75b99e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+sdf_parsing/build/
diff --git a/models/moving_platform/model.config b/models/moving_platform/model.config
new file mode 100644
index 0000000..052b4a1
--- /dev/null
+++ b/models/moving_platform/model.config
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<model>
+  <sdf version="1.9">model.sdf</sdf>
+</model>
diff --git a/models/moving_platform/model.sdf b/models/moving_platform/model.sdf
new file mode 100644
index 0000000..ea72d54
--- /dev/null
+++ b/models/moving_platform/model.sdf
@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<sdf version="1.9">
+  <model name="flat_platform">
+    <link name="platform_link">
+      <visual name="platform_visual">
+        <geometry>
+          <box>
+            <size>5 5 0.1</size>
+          </box>
+        </geometry>
+        <material>
+          <ambient>0.3 0.3 0.3 1</ambient>
+          <diffuse>0.3 0.3 0.3 1</diffuse>
+          <specular>0.1 0.1 0.1 1</specular>
+        </material>
+      </visual>
+      <collision name="platform_collision">
+        <geometry>
+          <box>
+            <size>5 5 0.1</size>
+          </box>
+        </geometry>
+      </collision>
+      <pose>0 0 2 0 0 0</pose>
+      <inertial>
+          <mass>10000</mass>
+          <inertia>
+              <ixx>10000</ixx>
+              <iyy>10000</iyy>
+              <izz>10000</izz>
+          </inertia>
+      </inertial>
+      <sensor name="navsat_sensor" type="navsat">
+        <always_on>1</always_on>
+        <update_rate>30</update_rate>
+      </sensor>
+    </link>
+    <!-- plugin for sending direct velocity commands -->
+    <plugin
+      filename="gz-sim-velocity-control-system"
+      name="gz::sim::systems::VelocityControl">
+    </plugin>
+    <plugin
+      filename="libMovingPlatformController.so"
+      name="custom::MovingPlatformController">
+    </plugin>
+  </model>
+</sdf>
diff --git a/worlds/moving_platform.sdf b/worlds/moving_platform.sdf
new file mode 100644
index 0000000..7ea1ae0
--- /dev/null
+++ b/worlds/moving_platform.sdf
@@ -0,0 +1,97 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<sdf version="1.9">
+  <world name="moving_platform">
+    <physics type="ode">
+      <max_step_size>0.004</max_step_size>
+      <real_time_factor>1.0</real_time_factor>
+      <real_time_update_rate>250</real_time_update_rate>
+    </physics>
+    <gravity>0 0 -9.8</gravity>
+    <magnetic_field>6e-06 2.3e-05 -4.2e-05</magnetic_field>
+    <atmosphere type="adiabatic"/>
+    <scene>
+      <grid>false</grid>
+      <ambient>0.4 0.4 0.4 1</ambient>
+      <background>0.7 0.7 0.7 1</background>
+      <shadows>true</shadows>
+    </scene>
+    <model name="ground_plane">
+      <static>true</static>
+      <link name="link">
+        <collision name="collision">
+          <geometry>
+            <plane>
+              <normal>0 0 1</normal>
+              <size>1 1</size>
+            </plane>
+          </geometry>
+          <surface>
+            <friction>
+              <ode/>
+            </friction>
+            <bounce/>
+            <contact/>
+          </surface>
+        </collision>
+        <visual name="visual">
+          <geometry>
+            <plane>
+              <normal>0 0 1</normal>
+              <size>500 500</size>
+            </plane>
+          </geometry>
+          <material>
+            <ambient>0.8 0.8 0.8 1</ambient>
+            <diffuse>0.8 0.8 0.8 1</diffuse>
+            <specular>0.8 0.8 0.8 1</specular>
+          </material>
+        </visual>
+        <pose>0 0 0 0 -0 0</pose>
+        <inertial>
+          <pose>0 0 0 0 -0 0</pose>
+          <mass>1</mass>
+          <inertia>
+            <ixx>1</ixx>
+            <ixy>0</ixy>
+            <ixz>0</ixz>
+            <iyy>1</iyy>
+            <iyz>0</iyz>
+            <izz>1</izz>
+          </inertia>
+        </inertial>
+        <enable_wind>false</enable_wind>
+      </link>
+      <pose>0 0 0 0 -0 0</pose>
+      <self_collide>false</self_collide>
+    </model>
+    <include>
+      <uri>model://moving_platform</uri>
+    </include>
+    <light name="sunUTC" type="directional">
+      <pose>0 0 500 0 -0 0</pose>
+      <cast_shadows>true</cast_shadows>
+      <intensity>1</intensity>
+      <direction>0.001 0.625 -0.78</direction>
+      <diffuse>0.904 0.904 0.904 1</diffuse>
+      <specular>0.271 0.271 0.271 1</specular>
+      <attenuation>
+        <range>2000</range>
+        <linear>0</linear>
+        <constant>1</constant>
+        <quadratic>0</quadratic>
+      </attenuation>
+      <spot>
+        <inner_angle>0</inner_angle>
+        <outer_angle>0</outer_angle>
+        <falloff>0</falloff>
+      </spot>
+    </light>
+    <spherical_coordinates>
+      <surface_model>EARTH_WGS84</surface_model>
+      <world_frame_orientation>ENU</world_frame_orientation>
+      <latitude_deg>47.397971057728974</latitude_deg>
+      <longitude_deg> 8.546163739800146</longitude_deg>
+      <elevation>0</elevation>
+    </spherical_coordinates>
+  </world>
+</sdf>