fix(nav2): improve mkmini gazebo steering simulation

src/mkmini_gazebo_steering_plugin/CMakeLists.txt

@@ -0,0 +1,15 @@
+cmake_minimum_required(VERSION 3.8)
+project(mkmini_gazebo_steering_plugin)
+
+find_package(ament_cmake REQUIRED)
+find_package(gazebo_ros REQUIRED)
+find_package(geometry_msgs REQUIRED)
+find_package(rclcpp REQUIRED)
+find_package(std_msgs REQUIRED)
+
+add_library(${PROJECT_NAME} SHARED src/steering_command_plugin.cpp)
+target_compile_features(${PROJECT_NAME} PUBLIC cxx_std_17)
+ament_target_dependencies(${PROJECT_NAME} gazebo_ros geometry_msgs rclcpp std_msgs)
+
+install(TARGETS ${PROJECT_NAME} LIBRARY DESTINATION lib)
+ament_package()

src/mkmini_gazebo_steering_plugin/package.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0"?>
+<package format="3">
+  <name>mkmini_gazebo_steering_plugin</name>
+  <version>1.0.0</version>
+  <description>Independent visual steering for the Gazebo MK-mini front wheels.</description>
+  <maintainer email="platform@autonomystudio.net">Autonomy Studio</maintainer>
+  <license>Apache-2.0</license>
+  <buildtool_depend>ament_cmake</buildtool_depend>
+  <depend>gazebo_ros</depend>
+  <depend>geometry_msgs</depend>
+  <depend>rclcpp</depend>
+  <depend>std_msgs</depend>
+</package>

src/mkmini_gazebo_steering_plugin/src/steering_command_plugin.cpp

@@ -0,0 +1,86 @@
+#include <algorithm>
+#include <cmath>
+#include <functional>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <utility>
+
+#include <gazebo/common/Events.hh>
+#include <gazebo/common/Plugin.hh>
+#include <gazebo/physics/physics.hh>
+#include <gazebo_ros/node.hpp>
+#include <geometry_msgs/msg/twist.hpp>
+#include <rclcpp/rclcpp.hpp>
+#include <std_msgs/msg/float64.hpp>
+
+namespace mkmini_gazebo_steering_plugin
+{
+class SteeringCommandPlugin : public gazebo::ModelPlugin
+{
+public:
+  void Load(gazebo::physics::ModelPtr model, sdf::ElementPtr sdf) override
+  {
+    left_joint_ = model->GetJoint(sdf->Get<std::string>("left_joint"));
+    right_joint_ = model->GetJoint(sdf->Get<std::string>("right_joint"));
+    if (!left_joint_ || !right_joint_) {
+      gzerr << "MK-mini visual steering joints were not found.\n";
+      return;
+    }
+    wheelbase_ = sdf->Get<double>("wheelbase", 0.60).first;
+    track_width_ = sdf->Get<double>("track_width", 0.72).first;
+    node_ = gazebo_ros::Node::Get(sdf);
+    const auto topic = sdf->Get<std::string>("topic", "/mkmini/steering_command").first;
+    subscription_ = node_->create_subscription<std_msgs::msg::Float64>(
+      topic, rclcpp::QoS(1),
+      [this](const std_msgs::msg::Float64::SharedPtr message) {
+        std::lock_guard<std::mutex> lock(mutex_);
+        target_angle_ = std::clamp(message->data, -0.5, 0.5);
+        has_target_ = true;
+      });
+    cmd_vel_subscription_ = node_->create_subscription<geometry_msgs::msg::Twist>(
+      "/cmd_vel", rclcpp::QoS(10),
+      [this](const geometry_msgs::msg::Twist::SharedPtr message) {
+        std::lock_guard<std::mutex> lock(mutex_);
+        target_angle_ = std::clamp(message->angular.z, -0.5, 0.5);
+        has_target_ = true;
+      });
+    update_connection_ = gazebo::event::Events::ConnectWorldUpdateBegin(
+      std::bind(&SteeringCommandPlugin::OnUpdate, this));
+  }
+
+private:
+  void OnUpdate()
+  {
+    std::lock_guard<std::mutex> lock(mutex_);
+    if (!has_target_ || !left_joint_ || !right_joint_) return;
+    const auto [left_angle, right_angle] = AckermannAngles(target_angle_);
+    left_joint_->SetPosition(0, left_angle);
+    right_joint_->SetPosition(0, right_angle);
+  }
+
+  std::pair<double, double> AckermannAngles(double steering_angle) const
+  {
+    if (std::abs(steering_angle) < 1e-6) return {0.0, 0.0};
+    const auto direction = steering_angle > 0.0 ? 1.0 : -1.0;
+    const auto radius = wheelbase_ / std::tan(std::abs(steering_angle));
+    const auto inner = std::atan(wheelbase_ / std::max(0.01, radius - track_width_ * 0.5));
+    const auto outer = std::atan(wheelbase_ / (radius + track_width_ * 0.5));
+    return direction > 0.0 ? std::make_pair(inner, outer) : std::make_pair(-outer, -inner);
+  }
+
+  gazebo::physics::JointPtr left_joint_;
+  gazebo::physics::JointPtr right_joint_;
+  gazebo::event::ConnectionPtr update_connection_;
+  gazebo_ros::Node::SharedPtr node_;
+  rclcpp::Subscription<std_msgs::msg::Float64>::SharedPtr subscription_;
+  rclcpp::Subscription<geometry_msgs::msg::Twist>::SharedPtr cmd_vel_subscription_;
+  std::mutex mutex_;
+  double wheelbase_{0.60};
+  double track_width_{0.72};
+  double target_angle_{0.0};
+  bool has_target_{false};
+};
+
+GZ_REGISTER_MODEL_PLUGIN(SteeringCommandPlugin)
+}  // namespace mkmini_gazebo_steering_plugin

src/nav2_turtlebot_simulator/CMakeLists.txt

@@ -2,6 +2,7 @@ cmake_minimum_required(VERSION 3.8)
 project(nav2_turtlebot_simulator)
 
 find_package(ament_cmake REQUIRED)
+find_package(mkmini_gazebo_steering_plugin REQUIRED)
 
 install(DIRECTORY launch worlds models DESTINATION share/${PROJECT_NAME})
 

src/nav2_turtlebot_simulator/launch/simulator.launch.py

@@ -220,21 +220,33 @@ def create_mkmini_world(gazebo_dir):
         except ValueError:
             continue
 
-    # The MKMini lidar is centered at 0.52 m. Raise the original 0.5 m white
+    # Keep only the centre post from TurtleBot3 World's 3x3 white-pillar grid.
-    # pillars so they remain observable obstacles instead of falling below the
+    # This is applied to the generated MKMini world only; Burger keeps the
-    # scan plane.
+    # original obstacle layout. Remove both visual and collision shapes so the
-    for element in (*model.findall('.//collision'), *model.findall('.//visual')):
+    # Gazebo scene and Nav2 costmap describe the same space.
-        cylinder = element.find('./geometry/cylinder')
+    for link in model.findall('.//link'):
-        if cylinder is None:
+        for element in list(link):
-            continue
+            if element.tag not in {'collision', 'visual'}:
-        if cylinder.findtext('radius') != '0.15' or cylinder.findtext('length') != '0.5':
+                continue
-            continue
+            cylinder = element.find('./geometry/cylinder')
-        cylinder.find('length').text = '1.2'
+            if cylinder is None:
-        pose = element.find('pose')
+                continue
-        if pose is None:
+            if cylinder.findtext('radius') != '0.15' or cylinder.findtext('length') != '0.5':
-            continue
+                continue
-        values = pose.text.split()
+            pose = element.find('pose')
-        if len(values) == 6:
+            values = pose.text.split() if pose is not None and pose.text else []
+            if len(values) != 6:
+                continue
+            try:
+                x, y = float(values[0]), float(values[1])
+            except ValueError:
+                continue
+            if abs(x) > 1e-6 or abs(y) > 1e-6:
+                link.remove(element)
+                continue
+            # The MKMini lidar is centered at 0.52 m. Raise the remaining
+            # centre post so it stays observable instead of below the scan.
+            cylinder.find('length').text = '1.2'
             values[2] = '0.6'
             pose.text = ' '.join(values)
 

src/nav2_turtlebot_simulator/models/mkmini_gazebo/model.sdf

@@ -1,8 +1,8 @@
 <?xml version="1.0"?>
 <sdf version="1.6">
-  <!-- Lightweight MK-mini approximation. The body dimensions and wheelbase
+  <!-- MK-mini's proven tricycle drive remains the collision and odometry model.
-       match the platform profile; Gazebo's tricycle plugin supplies stable
+       Its visible front wheels are separate steering links so the Gazebo view
-       non-holonomic Ackermann-like motion from the standard /cmd_vel topic. -->
+       follows real left/right Ackermann angles instead of a rotating axle. -->
   <model name="mkmini_gazebo">
     <pose>0 0 0.16 0 0 0</pose>
 
@@ -13,37 +13,25 @@
       <visual name="front_marker"><pose>0.56 0 0.68 0 0 0</pose><geometry><box><size>0.06 0.42 0.10</size></box></geometry><material><ambient>0.95 0.65 0.08 1</ambient><diffuse>0.95 0.65 0.08 1</diffuse></material></visual>
     </link>
 
-    <link name="front_fork"><pose>0.30 0 0 0 0 0</pose><inertial><mass>1.0</mass><inertia><ixx>0.01</ixx><iyy>0.01</iyy><izz>0.01</izz></inertia></inertial>
+    <link name="front_fork"><pose>0.30 0 0 0 0 0</pose><inertial><mass>1.0</mass><inertia><ixx>0.01</ixx><iyy>0.01</iyy><izz>0.01</izz></inertia></inertial></link>
-      <!-- Visual front-wheel pair. The tricycle plugin retains its hidden
-           centre drive wheel for stable steering and odometry. -->
-      <visual name="front_left_wheel_visual"><pose>0 0.36 0 1.5708 0 0</pose><geometry><cylinder><radius>0.14</radius><length>0.10</length></cylinder></geometry><material><ambient>0.04 0.04 0.04 1</ambient><diffuse>0.04 0.04 0.04 1</diffuse></material></visual>
-      <visual name="front_right_wheel_visual"><pose>0 -0.36 0 1.5708 0 0</pose><geometry><cylinder><radius>0.14</radius><length>0.10</length></cylinder></geometry><material><ambient>0.04 0.04 0.04 1</ambient><diffuse>0.04 0.04 0.04 1</diffuse></material></visual>
-    </link>
     <joint name="front_steering_joint" type="revolute"><parent>base_link</parent><child>front_fork</child><axis><xyz>0 0 1</xyz><limit><lower>-0.5</lower><upper>0.5</upper></limit></axis></joint>
-
     <link name="front_drive_wheel"><pose>0.30 0 0 0 0 0</pose><inertial><mass>1.2</mass><inertia><ixx>0.02</ixx><iyy>0.01</iyy><izz>0.02</izz></inertia></inertial><collision name="collision"><pose>0 0 0 1.5708 0 0</pose><geometry><cylinder><radius>0.14</radius><length>0.18</length></cylinder></geometry></collision></link>
     <joint name="front_drive_joint" type="revolute"><parent>front_fork</parent><child>front_drive_wheel</child><axis><xyz>0 1 0</xyz></axis></joint>
 
+    <link name="front_left_visual_wheel"><pose>0.30 0.36 0 0 0 0</pose><inertial><mass>0.05</mass><inertia><ixx>0.0001</ixx><iyy>0.0001</iyy><izz>0.0001</izz></inertia></inertial><visual name="visual"><pose>0 0 0 1.5708 0 0</pose><geometry><cylinder><radius>0.14</radius><length>0.10</length></cylinder></geometry><material><ambient>0.04 0.04 0.04 1</ambient><diffuse>0.04 0.04 0.04 1</diffuse></material></visual></link>
+    <joint name="front_left_visual_steering_joint" type="revolute"><parent>base_link</parent><child>front_left_visual_wheel</child><axis><xyz>0 0 1</xyz><limit><lower>-0.6</lower><upper>0.6</upper></limit></axis></joint>
+    <link name="front_right_visual_wheel"><pose>0.30 -0.36 0 0 0 0</pose><inertial><mass>0.05</mass><inertia><ixx>0.0001</ixx><iyy>0.0001</iyy><izz>0.0001</izz></inertia></inertial><visual name="visual"><pose>0 0 0 1.5708 0 0</pose><geometry><cylinder><radius>0.14</radius><length>0.10</length></cylinder></geometry><material><ambient>0.04 0.04 0.04 1</ambient><diffuse>0.04 0.04 0.04 1</diffuse></material></visual></link>
+    <joint name="front_right_visual_steering_joint" type="revolute"><parent>base_link</parent><child>front_right_visual_wheel</child><axis><xyz>0 0 1</xyz><limit><lower>-0.6</lower><upper>0.6</upper></limit></axis></joint>
+
     <link name="rear_left_wheel"><pose>-0.30 0.36 0 0 0 0</pose><inertial><mass>1.0</mass><inertia><ixx>0.02</ixx><iyy>0.01</iyy><izz>0.02</izz></inertia></inertial><collision name="collision"><pose>0 0 0 1.5708 0 0</pose><geometry><cylinder><radius>0.14</radius><length>0.10</length></cylinder></geometry></collision><visual name="visual"><pose>0 0 0 1.5708 0 0</pose><geometry><cylinder><radius>0.14</radius><length>0.10</length></cylinder></geometry><material><ambient>0.04 0.04 0.04 1</ambient><diffuse>0.04 0.04 0.04 1</diffuse></material></visual></link>
     <joint name="rear_left_joint" type="revolute"><parent>base_link</parent><child>rear_left_wheel</child><axis><xyz>0 1 0</xyz></axis></joint>
-
     <link name="rear_right_wheel"><pose>-0.30 -0.36 0 0 0 0</pose><inertial><mass>1.0</mass><inertia><ixx>0.02</ixx><iyy>0.01</iyy><izz>0.02</izz></inertia></inertial><collision name="collision"><pose>0 0 0 1.5708 0 0</pose><geometry><cylinder><radius>0.14</radius><length>0.10</length></cylinder></geometry></collision><visual name="visual"><pose>0 0 0 1.5708 0 0</pose><geometry><cylinder><radius>0.14</radius><length>0.10</length></cylinder></geometry><material><ambient>0.04 0.04 0.04 1</ambient><diffuse>0.04 0.04 0.04 1</diffuse></material></visual></link>
     <joint name="rear_right_joint" type="revolute"><parent>base_link</parent><child>rear_right_wheel</child><axis><xyz>0 1 0</xyz></axis></joint>
 
-    <link name="os_lidar"><pose>0 0 0.9 0 0 0</pose><inertial><mass>0.2</mass><inertia><ixx>0.001</ixx><iyy>0.001</iyy><izz>0.001</izz></inertia></inertial>
+    <link name="os_lidar"><pose>0 0 0.9 0 0 0</pose><inertial><mass>0.2</mass><inertia><ixx>0.001</ixx><iyy>0.001</iyy><izz>0.001</izz></inertia></inertial><visual name="visual"><geometry><cylinder><radius>0.075</radius><length>0.10</length></cylinder></geometry><material><ambient>0.85 0.12 0.10 1</ambient><diffuse>0.85 0.12 0.10 1</diffuse></material></visual><sensor name="lidar_2d" type="ray"><always_on>true</always_on><update_rate>10</update_rate><visualize>true</visualize><ray><scan><horizontal><samples>360</samples><resolution>1</resolution><min_angle>-3.14159</min_angle><max_angle>3.14159</max_angle></horizontal><vertical><samples>1</samples><resolution>1</resolution><min_angle>0</min_angle><max_angle>0</max_angle></vertical></scan><range><min>0.20</min><max>18.0</max><resolution>0.02</resolution></range></ray><plugin name="mkmini_lidar" filename="libgazebo_ros_ray_sensor.so"><ros><remapping>~/out:=/raw/lidar</remapping></ros><output_type>sensor_msgs/PointCloud2</output_type><frame_name>os_lidar</frame_name></plugin></sensor></link>
-      <visual name="visual"><geometry><cylinder><radius>0.075</radius><length>0.10</length></cylinder></geometry><material><ambient>0.85 0.12 0.10 1</ambient><diffuse>0.85 0.12 0.10 1</diffuse></material></visual>
-      <sensor name="lidar_2d" type="ray"><always_on>true</always_on><update_rate>10</update_rate><visualize>true</visualize><ray><scan><horizontal><samples>360</samples><resolution>1</resolution><min_angle>-3.14159</min_angle><max_angle>3.14159</max_angle></horizontal><vertical><samples>1</samples><resolution>1</resolution><min_angle>0</min_angle><max_angle>0</max_angle></vertical></scan><range><min>0.20</min><max>18.0</max><resolution>0.02</resolution></range></ray><plugin name="mkmini_lidar" filename="libgazebo_ros_ray_sensor.so"><ros><remapping>~/out:=/raw/lidar</remapping></ros><output_type>sensor_msgs/PointCloud2</output_type><frame_name>os_lidar</frame_name></plugin></sensor>
-    </link>
     <joint name="os_lidar_joint" type="fixed"><parent>base_link</parent><child>os_lidar</child></joint>
 
-    <plugin name="mkmini_tricycle" filename="libgazebo_ros_tricycle_drive.so">
+    <plugin name="mkmini_tricycle" filename="libgazebo_ros_tricycle_drive.so"><ros><remapping>cmd_vel:=/cmd_vel</remapping><remapping>odom:=/odom</remapping></ros><steering_joint>front_steering_joint</steering_joint><actuated_wheel_joint>front_drive_joint</actuated_wheel_joint><encoder_wheel_left_joint>rear_left_joint</encoder_wheel_left_joint><encoder_wheel_right_joint>rear_right_joint</encoder_wheel_right_joint><wheel_separation>0.72</wheel_separation><encoder_wheel_diameter>0.28</encoder_wheel_diameter><actuated_wheel_diameter>0.28</actuated_wheel_diameter><max_wheel_torque>120.0</max_wheel_torque><max_wheel_acceleration>1.5</max_wheel_acceleration><max_steering_speed>0.0</max_steering_speed><publish_odom>true</publish_odom><publish_wheel_tf>true</publish_wheel_tf><publish_wheel_joint_state>true</publish_wheel_joint_state><odometry_frame>odom</odometry_frame><robot_base_frame>base_link</robot_base_frame></plugin>
-      <ros><remapping>cmd_vel:=/cmd_vel</remapping><remapping>odom:=/odom</remapping></ros>
+    <plugin name="mkmini_visual_steering" filename="/modules/[lms-nav2-gazebo-simulator]nav2-simulator_v1.0.0_ws/install/mkmini_gazebo_steering_plugin/lib/libmkmini_gazebo_steering_plugin.so"><topic>/mkmini/steering_command</topic><left_joint>front_left_visual_steering_joint</left_joint><right_joint>front_right_visual_steering_joint</right_joint><wheelbase>0.60</wheelbase><track_width>0.72</track_width></plugin>
-      <steering_joint>front_steering_joint</steering_joint><actuated_wheel_joint>front_drive_joint</actuated_wheel_joint>
-      <encoder_wheel_left_joint>rear_left_joint</encoder_wheel_left_joint><encoder_wheel_right_joint>rear_right_joint</encoder_wheel_right_joint>
-      <wheel_separation>0.72</wheel_separation><encoder_wheel_diameter>0.28</encoder_wheel_diameter><actuated_wheel_diameter>0.28</actuated_wheel_diameter>
-      <max_wheel_torque>120.0</max_wheel_torque><max_wheel_acceleration>1.5</max_wheel_acceleration><max_steering_speed>0.8</max_steering_speed>
-      <publish_odom>true</publish_odom><publish_wheel_tf>true</publish_wheel_tf><publish_wheel_joint_state>true</publish_wheel_joint_state>
-      <odometry_frame>odom</odometry_frame><robot_base_frame>base_link</robot_base_frame>
-    </plugin>
   </model>
 </sdf>

src/nav2_turtlebot_simulator/package.xml

@@ -6,6 +6,7 @@
   <maintainer email="platform@autonomystudio.net">Autonomy Studio</maintainer>
   <license>Apache-2.0</license>
   <buildtool_depend>ament_cmake</buildtool_depend>
+  <build_depend>mkmini_gazebo_steering_plugin</build_depend>
   <exec_depend>gazebo_ros</exec_depend>
   <exec_depend>launch</exec_depend>
   <exec_depend>launch_ros</exec_depend>