Creating a new RTT Component for CoSiMA

It may happen that you are missing some functionality for your robotic system, which is not present amongst the predefined components in the CogIMon Component Library (CCL). In such a case you may need to create your own components that contains the desired functionality. These instructions present the common way to create a CoSiMA-conform Orocos RTT component, which can then be used with the modelling tools.

Implementing the Orocos RTT Component

  1. To boost productivity, we’ve created a template to download from our Github. 
    $ git clone https://github.com/cogimon/rtt-component-template.git

    The content look like this:

    $ cd rtt-component-template && tree .
.
├── CMakeLists.txt
├── include
│   └── simple-rtt-component.hpp
├── ops
│   └── simple_example.ops
├── README.md
└── src
    └── simple-rtt-component.cpp
  2. Change the name of the component in the .cpp / .hpp and the CMakeLists.txt to reflect its intended functionality.
    In CMakeLists.txt: 
     #..[ omitted ]..

 #
 # This creates a standard cmake project. You may extend this file with
 # any cmake macro you see fit.
 #
 project(sample-rtt-component) #  <--- Change the name

 #..[ omitted ]..

 orocos_component(
   ${CMAKE_PROJECT_NAME}
   ${PROJECT_SOURCE_DIR}/include/simple-rtt-component.hpp #  <--- Change the name
   ${PROJECT_SOURCE_DIR}/src/simple-rtt-component.cpp #  <--- Change the name
 ) #  <--- you may add multiple source files

 #..[ omitted ]..

    In .cpp / .hpp:

     #include "simple-rtt-component.hpp" //  <--- Change the name

 //..[ omitted ]..

 RttComponent::RttComponent(std::string const & name) : RTT::TaskContext(name) {} //  <--- Change the name

 //..[ omitted ]..

 // This macro, as you can see, creates the component. Every component should have this!
 ORO_CREATE_COMPONENT_LIBRARY()ORO_LIST_COMPONENT_TYPE(RttComponent) //  <--- Change the name
  3. Perform an out-of-source compilation inside the rtt-component-template folder and verify that the template compiles. 
    $ mkdir build && cd build
$ cmake -DCMAKE_INSTALL_PREFIX=<path-to-your-CoSiMA-installation> ..
$ make
  4. Change the functional implementation to your liking, see The Orocos Component Builder’s Manual as API reference. Further Do’s and Don’ts are outlined at the end of this section.

Making the Component Available for CoSiMA

  1. Make sure that your latest code has compiled properly.
  2. Verify that you have the following orocos folder in your build folder: 
    $ tree orocos
orocos
└── gnulinux
 └── RttExamples  #  <--- Name of the component library
     └── libRttExamples-gnulinux.so  #  <--- Component library
  3. Source the CoSiMA setup script. 
    $ source <path-to-your-CoSiMA-installation>/bin/setup-cogimon-env.sh
  4. Extend the RTT_COMPONENT_PATH by your new library (orocos folder). 
    $ export RTT_COMPONENT_PATH=$RTT_COMPONENT_PATH:<path-to-your-component-librarys-build-folder>/orocos
  5. Launch the deployer or deployer-<os>. 
     $ deployer-gnulinux
 Real-time memory: 517904 bytes free of 524288 allocated.
    Switched to : Deployer

   This console reader allows you to browse and manipulate TaskContexts.
   You can type in an operation, expression, create or change variables.
   (type 'help' for instructions and 'ls' for context info)

     TAB completion and HISTORY is available ('bash' like)

     Use 'Ctrl-D' or type 'quit' to exit this program.

 Deployer [S]> import("RttExamples") #  <--- Name of the component library
  = true

 Deployer [S]> displayComponentTypes
 I can create the following component types:
    OCL::ConsoleReporting
    OCL::FileReporting
    OCL::HMIConsoleOutput
    OCL::HelloWorld
    OCL::NetcdfReporting
    OCL::TcpReporting
    OCL::TimerComponent
    OCL::logging::Appender
    OCL::logging::FileAppender
    OCL::logging::GenerationalFileAppender
    OCL::logging::LoggingService
    OCL::logging::OstreamAppender
    OCL::logging::RollingFileAppender
    TaskContext
    RttComponent #  <--- Name of a component from the library
  = (void)

 Deployer [S]> loadComponent("name-component-inst", "RttComponent") #  <--- Name of a component from the library

Represent the Component in the Modelling Environment

  1. Start the CoSiMA IDE and create a new project solution.

    Create a new project solution in the CoSiMA IDE

  2. Create a new model and name it ccl.

    Create a new model and name it ccl

  3. Include the following dependencies.

    Include the following dependencies

  4. Create a new component in the model.

    Create a new component in the model

  5. Represent the component as it is in the c++ implementation.

    Represent the component as it is in the c++ implementation

  6. Compile the project solution.

    Compile the project solution

Do’s and Don’ts

  • DO implement in a real-time safe and capable way!

  • DO group components with high cohesion together!

  • DON’T generate the component interface (i.e. ports, operations, properties) in a magical way, since this is currently not supported by the modelling environment!
  • DON’T allocate memory in the updateHook!
  • DON’T use assertions or any other mechanisms that can lead to unforeseen segfaults of the whole system. That’s just DANGEROUS!