ROS: Robot Operating System. Presented by: Anqi Xu COMP-417, McGill University Tuesday September 16th, 2014

Transcription

1 ROS: Robot Operating System Presented by: Anqi Xu COMP-417, McGill University Tuesday September 16th, 2014

2 Overview Features & Philosophies Core elements Development pipeline Useful ROS nodes / tools

3 What is? Meta operating system (or middleware) Developed and Maintained by the Open Source Robotics Foundation (OSRF) The primary goal of ROS is to support code reuse in robotics research and development.

4 ROS Philosophies Modular & peer-to-peer Language independent Thin Free & open-source

5 ROS Philosophy: Modularity & Peer-to-Peer

6 ROS Philosophy: Language Independence Client interfaces: Stable: rospy, roscpp, roslisp Experimental: rosjava, roslua Contributed: rosserial (Arduino), roshask, ros4mat (MATLAB), ros4ios, etc... Common message-passing layer Interface Definition Language (IDL)

7 ROS Philosophy: Thin Library-style interaction Facilitates integration with other common libraries, e.g.: OpenCV, PCL, bullet, etc... Minimal dependencies Linked against (lean) ROS core + necessary message meta-libraries + specific libraries The preferred development model is to write ROS-agnostic libraries with clean functional interfaces.

8 ROS Philosophy: Free & Open-Source Source code publicly available ROS Core & first-party tools under BSD license Contributed tools under variety of open-source (& few closed-source) licenses Promotes code-reuse and community-building

9 ROS: Core Elements Nodes Messages, topics, and services ROS Master (Parameters) Bags

10 Nodes Single-purposed executable programs e.g. sensor driver(s), actuator driver(s), mapper, planner, UI, etc... Modular design Individually compiled, executed, and managed Nodelets

11 Messages Strictly-typed data structures for inter-node communication Interface Definition Language (IDL) Basic types: bool, [u]int{8,16,32,64}, float{32/64}, string, time, duration, etc... Arrays Nested messages: image, GPS, IMU, etc...

12 Topics Unidirectional (& often repeated) inter-node communication Publish/Subscribe model: 1-to-N broadcasting Examples: provide sensor readings provide actuator states / robot feedback

13 Services Synchronous inter-node transactions / RPC Service/Client model: 1-to-1 request-response Examples: carry out remote computation trigger functionality / behavior update dynamic parameter

14 ROS Master Naming & registration services for nodes, topics, services, etc... The role of the Master is to enable ROS nodes to locate one another. Critical environment variable: $ROS_MASTER_URI=

15 ROS: Topic Subscription (1) (2) (0) (6) (3) (4) (5)

16 ROS: Service Call

17 ROS Parameters Configurable setting Node-specific Launch-time Unique name Typed (XMLRPC) Can be remapped at runtime

18 ROS Bags Standardized logging & playback mechanism Single-file container for serialized messages Playback using simulated / real clock (Near-)real-time message playback (w/ < ~1ms offsets due to file IOs during bagging)

19 rosbuild vs. catkin rosbuild: highly customized CMake-derived build toolchain (fuerte or older distro, uses rosmake) Stack: collection of packages with single theme (e.g. for a single platform, from a single lab, etc ); requires stack.xml catkin: near-stock Cmake build toolchain (groovy or later distro, uses catkin_make) Meta-package: any folder with one or more packages Catkin workspace = single CMake project; all include subfolders are shared! Rising tide

20 rosbuild vs. catkin (cont.) How to tell them apart? manifest.xml = rosbuild; package.xml = catkin rosbuild workspace catkin workspace

21 ROS Development Pipeline Navigate: roscd, rosed Setup: catkin_init_workspace, catkin_create_pkg Configure: package.xml, CmakeLists.txt Build: catkin_make Execute: roscore, rosrun, roslaunch (, rosparam) Inspect: rosnode, rostopic, rosservice Debug: roswtf, rqt_graph (, rostest) Log & Analyze: rosbag, rqt_bag

22 Navigate: roscd / rosed Provides fast navigation to ROS folders / files roscd stage rosed wall_follow wall_follower.py export EDITOR='emacs -nw'

23 Setup: catkin_create_pkg Creates ROS catkin package catkin_create_pkg my_catkin_pkg roscpp std_msgs compiled binaries CMake build folder dynamic reconfigure settings C++ headers / auto-generated headers roslaunch files message types Python nodes C++ source files service types CMake project file ros.org documentation page (rosbuild) CMake-generated makefile node settings / dependencies (rosbuild)

24 Configure: package.xml Lists properties and ROS node dependencies <package> <name>camera_calibration</name> <version>1.11.6</version> <description> camera_calibration allows easy calibration of cameras [ ] </description> <author>james Bowman</author> <author>patrick Mihelich</author> <maintainer ="vincent.rabaud@gmail.com">vincent Rabaud</maintainer> <buildtool_depend version_gte="0.5.68">catkin</buildtool_depend> <test_depend>rostest</test_depend> <run_depend>cv_bridge</run_depend> <run_depend>image_geometry</run_depend> <run_depend>message_filters</run_depend> <run_depend>opencv2</run_depend> <run_depend>rospy</run_depend> <run_depend>std_srvs</run_depend> <run_depend>sensor_msgs</run_depend> <license>bsd</license> <url> <export> <rosdoc config="rosdoc.yaml" /> </export> </package>

25 Configure: CMakeLists.txt Configures build environment & lists non-ros dependencies cmake_minimum_required(version 2.8.3) project(my_catkin_package) find_package(catkin REQUIRED) find_package(boost REQUIRED COMPONENTS system) add_message_files( FILES Message1.msg Message2.msg ) add_service_files( FILES Service1.srv Service2.srv ) generate_messages( DEPENDENCIES std_msgs ) catkin_package( INCLUDE_DIRS include LIBRARIES my_catkin_package CATKIN_DEPENDS other_catkin_pkg DEPENDS system_lib ) include_directories(include) add_library(my_library src/${project_name}/lib.cpp ) add_executable(my_node src/node.cpp) add_dependencies(my_node my_catkin_package_generate_messages_cpp) target_link_libraries(my_node ${catkin_libraries} {Boost_LIBRARIES} my_library) install(targets my_library my_node ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION} LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION} RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION} ) install(directory include/${project_name}/ DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION} FILES_MATCHING PATTERN "*.h" PATTERN ".svn" EXCLUDE ) catkin_add_gtest(${project_name}-test test/test_my_node.cpp) if(target ${PROJECT_NAME}-test) target_link_libraries(${project_name}-test ${PROJECT_NAME}) endif()

26 Build: catkin_make Builds all ROS nodes in catkin workspace All include folders from packages are shared, so use subfolders to prevent name clashes (e.g. catkin_ws/my_pkg/include/my_pkg/file.h) rosmake alternative: rosmake wall_follow ~= roscd wall_follow; mkdir build; cd build; cmake..

27 Build: catkin_make Builds all ROS nodes in catkin workspace All include folders from packages are shared, so use subfolders to prevent name clashes (e.g. catkin_ws/my_pkg/include/my_pkg/file.h)

28 Execute: roscore Starts ROS master Only 1 master per machine Hostname (cat /etc/hostname) must be defined in /etc/hosts Connecting to another ROS master over network Both hostnames defined in both machines /etc/hosts export ROS_MASTER_URI=

29 Execute: rosrun Executes ROS node namespace remappings node-specific parameters (use '--' to delineate) rosrun image_view image_view image:=/camera/image_raw -- compressed

30 Execute: roslaunch Executes multiple ROS nodes concurrently Launch files should have.launch extension, to be indexed automatically Will initialize ROS master automatically if needed roslaunch image_proc image_proc.launch <roslaunch> <namespace galapagos > <node pkg= turtlesim node= turtlesim_node required= true /> <node pkg= turtlesim node= turtle_teleop_key output= screen > <param name= scale_linear value= /> </node> </namespace> </roslaunch>

31 Execute: rosparam Absolute parameters: /node/param Local parameters: ~param YAML syntax rosparam list rosparam set /foo "['1', 1, 1.0]" rosrun camera1394 camera1394_node video_mode= 640x480_mono8

32 Inspect: rosnode, rostopic, rosservice Lists nodes/topics/services and provides information on their states rosnode list rostopic echo /turtle1/pose rostopic pub -1 /text_listener std_msgs/string -- "Hello World" rostopic hz /camera/image_raw rosservice call /kill

33 Debug: rostest Executes unit test on ROS node C++: gtest, Python: unittest In CmakeLists.txt: catkin_add_gtest(test1 test/test1.cpp) ROSLaunch: <test test-name= test1 pkg= my_pkg type= test1 /> rostest mypkg test1.test

34 Debug: Python unittest #!/usr/bin/env python PKG = 'mypkg' import roslib; roslib.load_manifest(pkg) import sys import unittest ## A sample python unit test class TestBareBones(unittest.TestCase): ## test 1 == 1 def test_one_equals_one(self): self.assertequals(1, 1, "1!=1") if name == ' main ': import rostest rostest.rosrun(pkg, 'test_bare_bones', TestBareBones)

35 Debug: roswtf & rqt_graph roswtf: finds trivial mistakes (e.g. ROS node not responding, missing publisher, etc...) rqt_graph: visualize nodes & messages

36 Log & Analyze: rosbag Records and plays back sets of messages rosbag record -a rosbag record rosout tf turtle1/pose rosbag play -r 1.5 -s 30 -l yesterday.bag rosbag compress *.bag rosbag reindex *.bag

37 Log & Analyze: rqt_bag GUI for visualizing rosbag content

38 Tool: rqt_reconfigure Changes parameters dynamically in runtime NOT the same as (static) ROS parameters! rosrun rqt_reconfigure rqt_reconfigure

39 Tools: rviz Fully-featured 3D visualization environment

40 Tools: tf Abstraction & manipulation of multiple coordinate frames (Timed) conversion between different frames Distributed broadcaster/listener model

41 Tool: actionlib Lengthy / complex /multi-step services Goal: desired end-result Feedback: incremental progress towards goal Result: feedback upon completion of goal

42 Next Steps wiki.ros.org/ros/tutorials answers.ros.org