http://gazebosim.org/tutorials?tut=ros_gzplugins&cat=connect_ros
今日は上記を見ながら、ロボットを作成していきます。ただし、記述が古いのでそのままだとうまく行きません。
まずは、GazeboからROS2を動かすデモを起動して理解を深めます。
次のコマンドでGazeboを起動します。
gazebo --verbose /opt/ros/foxy/share/gazebo_plugins/worlds/gazebo_ros_diff_drive_demo.world
teleopで操作してみます。
ros2 run teleop_twist_keyboard teleop_twist_keyboard cmd_vel:=/demo/cmd_demo
今回は差動二輪ロボットであるので、Differential Driveを実装します。gazebo_ros_diff_drive_demo.worldの中身をみて、そのまま真似て作成します。以下のような記述をロボットのsdfに追加します。
<!-- プラグインをロードします。 filenameは共有ライブラリのファイル名です。 --> <plugin name="differential_drive_controller" filename="libgazebo_ros_diff_drive.so"> <ros> <namespace>/momo</namespace> </ros> <!-- 左右の車輪のジョイントを指定します。 このジョイントにアクチュエータが追加され、制御可能になります。 --> <left_joint>wheel_left_joint</left_joint> <right_joint>wheel_right_joint</right_joint> <!-- ロボットのオドメトリの中心となるフレームです。 rviz等でロボットの位置を可視化するときにこのフレームを利用します。 --> <robot_base_frame>base_link</robot_base_frame> <!-- 車輪の間の距離です。 --> <wheel_separation>0.540</wheel_separation> <!-- 車輪の直径です。ホイールの直径（メートル単位）は、デフォルトで0.15mです。 --> <wheel_diameter>0.615</wheel_diameter> <!-- ホイールの加速度（rad / s ^ 2）は、デフォルトで0.0 rad / s ^ 2になります。--> <max_wheel_acceleration>1.0</max_wheel_acceleration> <!-- ホイールが生成できる最大トルク（Nm）は、デフォルトで5Nmです。 --> <max_wheel_torque>20</max_wheel_torque> <!-- オドメトリフレーム、デフォルトは `odom` --> <odometry_frame>odom</odometry_frame> <!-- オドメトリを計算するロボットフレーム。デフォルトは `base_footprint`です。 --> <robotBaseFrame>base_footprint</robotBaseFrame> <!-- オドメトリソース、エンコーダの場合は0、WORLDの場合は1、デフォルトはWORLD --> <odometrySource>1</odometrySource> <!-- ホイールリンクの変換を公開するにはtrueに設定する。デフォルト設定はfalse。--> <publish_wheel_tf>true</publish_wheel_tf> <!-- オドメトリを公開するにはtrueに設定する。 --> <publish_odom>true</publish_odom> <!-- オドメトリの変換を公開するにはtrueに設定する。 --> <publish_odom_tf>true</publish_odom_tf> </plugin>
では実際に動作させてみます。空のworldに入れてチェックします。
<?xml version="1.0"?> <sdf version="1.6"> <world name="default"> <include> <uri>model://ground_plane</uri> </include> <include> <uri>model://sun</uri> </include> <scene> <shadows>false</shadows> </scene> <gui fullscreen='0'> <camera name='user_camera'> <pose frame=''>0.319654 -0.235002 9.29441 0 1.5138 0.009599</pose> <view_controller>orbit</view_controller> <projection_type>perspective</projection_type> </camera> </gui> <physics type="ode"> <real_time_update_rate>1000.0</real_time_update_rate> <max_step_size>0.001</max_step_size> <real_time_factor>1</real_time_factor> <ode> <solver> <type>quick</type> <iters>150</iters> <precon_iters>0</precon_iters> <sor>1.400000</sor> <use_dynamic_moi_rescaling>1</use_dynamic_moi_rescaling> </solver> <constraints> <cfm>0.00001</cfm> <erp>0.2</erp> <contact_max_correcting_vel>2000.000000</contact_max_correcting_vel> <contact_surface_layer>0.01000</contact_surface_layer> </constraints> </ode> </physics> <include> <uri>model://momo</uri> </include> </world> </sdf>
実行します。
$ gazebo --verbose momo_ws/src/momo_gazebo/worlds/static_map_plugin_get.world Gazebo multi-robot simulator, version 11.5.1 Copyright (C) 2012 Open Source Robotics Foundation. Released under the Apache 2 License. http://gazebosim.org [Msg] Waiting for master. Gazebo multi-robot simulator, version 11.5.1 Copyright (C) 2012 Open Source Robotics Foundation. Released under the Apache 2 License. http://gazebosim.org [Msg] Waiting for master. [Msg] Connected to gazebo master @ http://127.0.0.1:11345 [Msg] Publicized address: 192.168.86.42 [Msg] Connected to gazebo master @ http://127.0.0.1:11345 [Msg] Publicized address: 192.168.86.42 [Msg] Loading world file [/home/hiroakikaneda/momo_ws/src/momo_gazebo/worlds/static_map_plugin_get.world] [Wrn] [ColladaLoader.cc:1928] Triangle input semantic: 'COLOR' is currently not supported [Wrn] [ColladaLoader.cc:1928] Triangle input semantic: 'COLOR' is currently not supported [Wrn] [ColladaLoader.cc:1928] Triangle input semantic: 'COLOR' is currently not supported [Wrn] [ColladaLoader.cc:1928] Triangle input semantic: 'COLOR' is currently not supported [Wrn] [ColladaLoader.cc:1928] Triangle input semantic: 'COLOR' is currently not supported [Wrn] [ColladaLoader.cc:1928] Triangle input semantic: 'COLOR' is currently not supported [Wrn] [ColladaLoader.cc:1928] Triangle input semantic: 'COLOR' is currently not supported [Wrn] [ColladaLoader.cc:1928] Triangle input semantic: 'COLOR' is currently not supported [INFO] [1632923283.195835717] [gazebo_ros_node]: ROS was initialized without arguments. [INFO] [1632923283.214245446] [momo.differential_drive_controller]: Wheel pair 1 separation set to [0.540000m] [INFO] [1632923283.214581649] [momo.differential_drive_controller]: Wheel pair 1 diameter set to [0.615000m] [INFO] [1632923283.216477829] [momo.differential_drive_controller]: Subscribed to [/momo/cmd_vel] [INFO] [1632923283.217386722] [momo.differential_drive_controller]: Advertise odometry on [/momo/odom] [INFO] [1632923283.218196407] [momo.differential_drive_controller]: Publishing odom transforms between [odom] and [base_link] [INFO] [1632923283.218218133] [momo.differential_drive_controller]: Publishing wheel transforms between [base_link], [wheel_left_joint] and [wheel_right_joint] ^C[INFO] [1632924658.173345571] [rclcpp]: signal_handler(signal_value=2) [Wrn] [Publisher.cc:136] Queue limit reached for topic /gazebo/default/visual, deleting message. This warning is printed only once. hiroakikaneda@:~$ gazebo --verbose momo_ws/src/momo_gazebo/worlds/empty.world Gazebo multi-robot simulator, version 11.5.1 Copyright (C) 2012 Open Source Robotics Foundation. Released under the Apache 2 License. http://gazebosim.org [Msg] Waiting for master. Gazebo multi-robot simulator, version 11.5.1 Copyright (C) 2012 Open Source Robotics Foundation. Released under the Apache 2 License. http://gazebosim.org [Msg] Waiting for master. [Msg] Connected to gazebo master @ http://127.0.0.1:11345 [Msg] Publicized address: 192.168.86.42 [Msg] Loading world file [/home/hiroakikaneda/momo_ws/src/momo_gazebo/worlds/empty.world] [INFO] [1632924661.728514279] [gazebo_ros_node]: ROS was initialized without arguments. [INFO] [1632924661.747010815] [momo.differential_drive_controller]: Wheel pair 1 separation set to [0.540000m] [INFO] [1632924661.747259540] [momo.differential_drive_controller]: Wheel pair 1 diameter set to [0.615000m] [INFO] [1632924661.748479147] [momo.differential_drive_controller]: Subscribed to [/momo/cmd_vel] [INFO] [1632924661.749557110] [momo.differential_drive_controller]: Advertise odometry on [/momo/odom] [INFO] [1632924661.750442843] [momo.differential_drive_controller]: Publishing odom transforms between [odom] and [base_link] [INFO] [1632924661.750501497] [momo.differential_drive_controller]: Publishing wheel transforms between [base_link], [wheel_left_joint] and [wheel_right_joint] [Msg] Connected to gazebo master @ http://127.0.0.1:11345 [Msg] Publicized address: 192.168.86.42
teleopで操作します。
$ ros2 run teleop_twist_keyboard teleop_twist_keyboard --ros-args --remap cmd_vel:=/momo/cmd_vel This node takes keypresses from the keyboard and publishes them as Twist messages. It works best with a US keyboard layout. --------------------------- Moving around: u i o j k l m , . For Holonomic mode (strafing), hold down the shift key: --------------------------- U I O J K L M < > t : up (+z) b : down (-z) anything else : stop q/z : increase/decrease max speeds by 10% w/x : increase/decrease only linear speed by 10% e/c : increase/decrease only angular speed by 10% CTRL-C to quit currently: speed 0.5 turn 1.0