Programming with the Default Middleware for Robotics Adopted in ROS2.

1. Fast RTPS: Programming with the Default
Middleware for Robotics Adopted in ROS2
FIWARE Summit
21/02/2019
Jaime Martin Losa
CEO eProsima
JaimeMartin@eProsima.com
+34 607 91 37 45 www.eProsima.com

2. Agenda
§ Fast RTPS
• Motivation
• Introduction
□ DDS
□ Architecture
□ Shapes Demo
• Hello World Example
§ FIROS2: Quick update (if there is time)
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3. Fast RTPS
Powering ROS2 & FIWARE

4. We are hiring!
§Jobs@eprosima.com
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5. Fast RTPS - Motivation
§ Real Time Requirements
• Latency measured in µSec
§ High Throughput Requirements
• Take advantage of Pub/Sub Architecture
§ Low bandwidth, intermittent and unreliable datalinks
• Radio networks
• Wifi
§ Many to Many communications
§ Decoupled architectures
§ Different QoS over different datalinks and performance requirements.
§ Efficient Data Models
4

6. Fast RTPS - Motivation
§ C++
§ Full RTPS (Real Time Publish Subscribe) implementation
§ Security (Encryption and Authentication)
§ RPC layer available through eProsima RPC over DDS
§ Based on OMG standards, Interoperable.
§ Comprehensive docs, videos, examples, etc.
§ Multi-Platform: Windows, Linux, Android, Mac OS, iOS
• Many ports developed by the community
§ Robotics Adoption (ROS2)
§ Apache 2.0 License
5

7. Fast RTPS: Key Features
§ RTPS focused:
• Access to the protocol internals
§ Large Data Support:
• Fragmentation and Flow controllers.
§ DDS Security:
• Authentication, Encryption, Access control
§ Support for Static Discovery/Server based discovery
• Faster Discovery.
§ XML QoS Profiles (Available for ROS2 also)
• See ROSCON 2017 Presentation
https://roscon.ros.org/2017/presentations/ROSCon%202017%20ROS2%20Fine
%20Tuning.pdf
• Fine tunning for extreme scenarios. 6

8. Fast RTPS: Key Features II
§ Fully Open Source
• Apache 2.0
• Community of Contributors
• User ports for many platforms.
• No vendor lock-in
§ Lightweight
§ Commercial Support
• Fast Response
• User Driven Roadmap
§ Aligned with OS Community:
• ROS2, Dronecode, FIWARE
§ Standard
7

9. New Releases. What is new?
§ Fast RTPS 1.8 (May 2019):
§ Better Real-Time Support
• Static allocations
• Non-Blocking calls
§ Better QoS support
• Lifespan
• Manual Liveliness
• Deadline
• Reliability: Disable positive ACKs
§ Server Discovery
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§ Fast RTPS 1.7 (Dec 2018):
§ TCP Transport: Fast RTPS on WAN/Internet
§ Dynamic Types
§ Updated to latest DDS Security Spec.
§ Important Performance improvements (ROS related)
§ Aligned with the upcoming ROS 2 Release (Crystal)
§ Fast RTPS 1.6 (June 2018):
§ Access Control
§ History persistence in database (sqlite).

10. Why Fast-RTPS for ROS2?
§ Fully Open-Source & Free:
• All features are Open Source
• Open Source Business model
• Contributors Community
§ Roadmap Aligned with ROS2 Roadmap
§ ROS2 TSC Members
• eProsima is a key contributor to ROS2
□ Fast RTPS: ROS2
□ Fast RTPS Security: Secure ROS2
□ XRCE-DDS: Micro-ROS
□ Integration Tools.
9

11. FIROS2 New Release
§ Connect Context Broker with Fast RTPS/ROS2
§ Already available in github:
• https://github.com/eProsima/FIROS2
§ The future: ROS Integration Service
• Coming soon, stay tuned.
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12. DDS: Standards-based Integration Infrastructure for Critical
Applications
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Streaming
Data
Sensors Events
Real-Time
Applications
Enterprise
Applications Actuators

13. Family of Specifications
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14. Broad Adoption
§ Vendor independent
• API for portability
• Wire protocol for interoperability
§ Multiple implementations
• 10 of API
• 8 support RTPS
§ Heterogeneous
• C, C++, Java, .NET (C#, C++/CLI)
• Linux, Windows, VxWorks, other embedded & real time
§ Loosely coupled
13

15. DDS adopted by key programs in Europe
§ European Air Traffic Control
• DDS proposed for interoperate
ATC centers
§ Spanish Army
• DDS is mandated for C2
Interoperability (ethernet, radio &
satellite)
§ UK Generic Vehicle
Architecture
• Mandates DDS for vehicle comm.
• Mandates DDS-RTPS for interop.
14

16. US-DoD mandates DDS for data-distribution
§ DISR (formerly JTA)
• DoD Information Technology
Standards Registry
§ US Navy Open Architecture
§ Army, OSD
• UCS, Unmanned Vehicle Control
§ SPAWAR NESI
• Net-centric Enterprise Solutions for
Interoperability
• Mandates DDS for Pub-Sub SOA
15

17. RTPS Adoption
§ ROS (Robotic Operating System)
§ FIWARE
• EU R&D Software Platform
§ Many Drone Companies
• 3D Robotics
• Magma UAVs
• …
§ Dronecode
• Main OSS platform for Drones
16

18. ROS2: Robotics de facto Standard
§ The Robot Operating System (ROS) is a set of software libraries and tools that help
you build robot applications. From drivers to state-of-the-art algorithms, and with
powerful developer tools, ROS has what you need for your next robotics project. And
it's all open source. ROS has become a de facto standard for Robotic applications.
§ OSRF Sponsors: Bosh, DARPA, google, MathWorks, Nasa, Nissan, Qualcomm,
rethink robotics, ROS-Industrial Consortium, Sandia National Laboratories, SICK,
Willow Garage, Yujin Robot
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19. DDS Architecture

20. DDS
§ DDS (Data Distribution Service for Real-Time Systems) is a OMG
specification for a pub/sub data centric model (DCPS, Data Centric
Publish/Subscribe) for Real-Time data comms in distributed systems.
§ DDS is a networking middleware that:
• Simplifies and Standardizes data flows in distributed real-time systems.
• Provides robust comms (no single point of failure) and efficient (minimum
latency)
• Provides all kind of QoS to shape the data flows and deliver predictable results.
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21. DDS
§ DDS uses the concept of Global Data Space. In this Space we define topics of
data, and the publishers publish samples of these topics. DDS distributes these
samples to all the subscribers of those topics. Any node can be a publisher or a
subscriber.
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22. Why DDS? Decoupled model
§ Space (location)
• Automatic Discovery ensures network topology independence
§ Redundancy:
• It is possible to configure redundant publishers and subscribers, primary/secundary and
takeover schemas supported
§ Time:
• The reception of data does not need to be synchronous with the writing. A subscriber
may, if so configured, receive data that was written even before the subscriber joined the
network.
§ Platform:
• Applications do not have to worry about data representation, processor architecture,
Operating System, or even programming language on the other side
§ Implementation:
• DDS Protocol is also an standard. Different implementations interoperate.
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23. Why DDS? Fully configurable
22
QoS Policy
DURABILITY
HISTORY
READER DATA LIFECYCLE
WRITER DATA LIFECYCLE
LIFESPAN
ENTITY FACTORY
RESOURCE LIMITS
RELIABILITY
TIME BASED FILTER
DEADLINE
CONTENT FILTERS
Volatility
UserQoS
Delivery
PresentationRedundancy
Infrastructure
Transport
QoS Policy
USER DATA
TOPIC DATA
GROUP DATA
PARTITION
PRESENTATION
DESTINATION ORDER
OWNERSHIP
OWNERSHIP STRENGTH
LIVELINESS
LATENCY BUDGET
TRANSPORT PRIORITY

24. DDS Infrastructure
§ Standard API for
portability.
§ RTPS can be
implemented over any
transport
§ No central
Broker/Service
§ Different Comm
channel per topic
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25. The DDS Model
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Quality of Service: QoS
Domain Participant
Data
Reader
Node
Subscriber
Data Domain
Subscriber
Data
Writer
Data
Writer
Data
Reader
Data
Reader
Data
Writer
Publisher
Topic
Publisher
Topic Topic

26. Topics, Instances and Keys
§ Topic: A set of similar objects, sharing a common Data Type
§ Instance: A particular object of the set
§ Key: Fields of the Data Type to identify an object.
25
Qos Applied
by Instance.
Topic: RadarTrack
Key: Flight ID
Instance
Flight ID=
MAD-BER57
Instance
Flight ID=
PAR-BER89
Instance
Flight ID=
PAR-BER89

27. Demo
26
const long STR_LEN=24;
struct ShapeType {
string<MSG_LEN> color; //@key
long x;
long y;
long shapesize;
};
• 3 Topics:
• Square, Circle,
Triangle
• Color is the KEY

28. Questions?
Jaime Martin Losa
CTO eProsima
JaimeMartin@eProsima.com
+34 607 91 37 45 www.eProsima.com

29. Fast RTPS Hands On:
A Hello World

30. Hands-on Example (C++)
29
Type
Definition
MyType.idl
fastrtpsgen
MyType.h
MyTypePubSubTypes.c
MyTypePublisher.cxx
MyTypeSubscriber.cxx
MyType.sln
Publisher Subscriber.exe
Three minutes to a running app!!
1. Define your data
2. Create your project
3. Build
4. Run: publisher subscriber
compiler

31. Example #1 - Hello World
30
We will use this data-type :
const long MSG_LEN=256;
struct HelloMsg {
string<MSG_LEN> user; //@key
string<MSG_LEN> msg;
};

32. Generate type support (for C++) [Windows]
31
fastrtpsgen HelloMsg.idl -example x64Win64VS2015
-replace -ppDisable
l Look at the directory you should see:
– solution-x64Win64VS2015.sln
– And Several other files…
l Open the Solution:
l Compile from visual studio

33. Execute the program [Windows]
§ C++:
• On one window run:
□ binx64Win64VS2015HelloMsgPublisherSubscriberd.exe publisher
• On another window run:
□ binx64Win64VS2015HelloMsgPublisherSubscriberd.exe subscriber
§ You should see the subscribers getting an empty string…
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34. Writting some data
§ Modify HelloMsgPublisher.cxx:
33
/* Main loop */
do
{
if(ch == 'y')
{
st.msg() = std::string("Hello using cpp ") +
std::to_string(msgsent);
mp_publisher->write(&st); ++msgsent;
cout << "Sending sample, count=" << msgsent <<
",send another sample?(y-yes,n-stop): ";
}

35. How to Get Data? (Listener-Based)
34
// Listener code
void HelloMsgSubscriber::SubListener::onNewDataMessage(Subscriber* sub)
{
// Take data
HelloMsg st;
if(sub->takeNextData(&st, &m_info))
{
if(m_info.sampleKind == ALIVE)
{
// Print your structure data here.
++n_msg;
cout << "Sample received, count=" << n_msg << endl;
cout << " " << st.msg() << endl;
}
}
}

36. Questions?
Jaime Martin Losa
CTO eProsima
JaimeMartin@eProsima.com
+34 607 91 37 45 www.eProsima.com

37. Thank you!
http://fiware.org
Follow @FIWARE on Twitter
Jaime Martin Losa
CTO eProsima
JaimeMartin@eProsima.com
+34 607 91 37 45 www.eProsima.com