• RT-Component with DataPorts
  • Overview of the RTC
  • Creating template codes of MRCConverter
    • Creating working folder
    • Using rtc-template (CUI version)
    • Running rtc-template (with gen.bat)
    • RtcTemplate on Eclipse (GUI version)
  • Running copyprops.bat
  • Implementing MRCConvertor
    • Launching Visual Studio
    • Implementing Header File
    • Implementing Source File
  • Running Build Proces
  • Creating rtc.conf
  • Running Component
    • Starting CORBA Name Server
    • Running MRCConvertorComp.exe

RT-Component with DataPorts

Here, how to develop RT-Component(MRCConverter) with DataPort would be shown.

Overview of the RTC

This RTC converts x-y value from input device (ex. joystick) to the wheel velocity of differential drive mobile robot.

The specification of the RTC is the following.

• InPort
  • Input values of x-y from joystick (TimedFloatSeq)

• OutPort
  • Wheel velocity to the mobile robot (TimedFloatSeq)

Creating template codes of MRCConverter

Here, how to create template codes by using RtcTemplate would be shown.

Creating working folder

Create working directory in any place. In the following, the directory name is MRCConverter.

1. Double-click "My Computer"
2. Move to working folder
3. Create new folder on the target folder

Using rtc-template (CUI version)

Create the following batch file (ex. gen.bat) on the working folder to run the rtc-template easily.

 rtc-template.py -bcxx^
  --module-name=MRCConvertor --module-desc="Convertor component for MobileRobot component"^
  --module-version=1.0.0 --module-vendor=AIST --module-category=Category^
  --module-comp-type=DataFlowComponent --module-act-type=PERIODIC^
  --module-max-inst=1^
  --inport=velFromInput:TimedFloatSeq^
  --outport=velToWheel:TimedFloatSeq

Running rtc-template (with gen.bat)

Run the gen.bat, and the result will be the following.

 >gen.bat
  rtc-template.py -bcxx
  --module-name=MRCConvertor
  --module-desc="Convertor component for MobileRobot component"
  --module-version=1.0.0 --module-vendor=AIST
  --module-category=Category
  --module-comp-type=DataFlowComponent --module-act-type=PERIODIC
  --module-max-inst=1
  --inport=velFromInput:TimedFloatSeq --outport=velToWheel:TimedFloatSeq
   File "MRCConvertor.h" was generated.
   File "MRCConvertor.cpp" was generated.
   File "MRCConvertorComp.cpp" was generated.
   File "Makefile.MRCConvertor" was generated.
   File "MRCConvertorComp_vc8.vcproj" was generated.
   File "MRCConvertor_vc8.vcproj" was generated.
   File "MRCConvertorComp_vc9.vcproj" was generated.
   File "MRCConvertor_vc9.vcproj" was generated.
   File "MRCConvertor_vc8.sln" was generated.
   File "MRCConvertor_vc9.sln" was generated.
   File "copyprops.bat" was generated.
   File "user_config.vsprops" was generated.
   File "README.MRCConvertor" was generated.
   File "MRCConvertor.yaml" was generated.

Some source codes and other files would be generated in the woking diretory.

RtcTemplate on Eclipse (GUI version)

Input the following profiles in the RtcTempalte's editor window.

• Programing language selection: C++
• Module definition
  • Module name: MRCConvertor
  • Module decription: Convertor component for MobileRobot component
  • Module version: 1.0.0
  • Module vender: AIST
  • Module category: Category
  • Component type: DataFlowComponent
  • Component's activity type: PERIODIC
  • Number of maximum instance: 1
• InPort definition
  • Ports: Name:velFromInput Type:TimedFloatSeq
• OutPort definition
  • Ports: Name:velToWheel, Type:TimedFloatSeq

After input the component profile, push "Generate" button. Some source codes and other files would be generated in the working folder.

Running copyprops.bat

As the result of the above mentioned operation, copyprops.bat would be generated in the working folder. The copyprops.bat copies rtm_config.vsprops (Visual Studio Property Sheet) from installed OpenRTM-aist folder to current working folder. This file is necessary to build RTC on Visual C++.

Double-click te copyprops.bat.

Implementing MRCConvertor

Launching Visual Studio

Double-click MRCConvertorComp_vc?.sln and launch Visual Studio. XXX_vc8.sln is a solution file for VC2005, XXX_vc9.sln is a solution file for VC2008. Please select an appropriate solution file for your development environment.

Implementing Header File

Open the MRCConverter.h in "MRCConverterComp" -> "Header Files" from Solution Explorer.

• Including other header files
  Since this RTC uses STL vector and math library, include these two header files.

 #include <vector>
 // To use Math::M_PI in VC8
 #define _USE_MATH_DEFINES
 #include <math.h>

• Uncomment "virtual RTC::ReturnCode_t onExecute(RTC::UniqueId ec_id);"

• Declaration of member variable and member function
  Declare a "convert()" function and its coefficient value "m_k" converting from input value to output wheel velocity.

 private:  float m_k;
 
  /*!
   * @brief This function converts input data from joystick to velocity of
   *        differential drive mobile robot.
   *        Only m_velFromInput.data[0 and 1] would be used.
   */
  std::vector<float> convert(float x, float y) {
    float th = atan2(y,x);
    float v  = m_k * hypot(x,y);
    std::vector<float> ret_val;
    ret_val.push_back(v * cos(th - (M_PI/4.0))); // left vel
    ret_val.push_back(v * sin(th - (M_PI/4.0))); // right vel
    return ret_val;
  }

Implementing Source File

Open the MRCConverter.cpp in "MRCConverterComp" -> "Source Files" from Solution Explorer.

• Implementing onExecute()
  Uncomment "onExecute()" function and implement it as follows.

 /*!
  * @brief This function converts input data from joystick to velocity of
  *        differential drive mobile robot.
  */
 RTC::ReturnCode_t MRCConvertor::onExecute(RTC::UniqueId ec_id)
 {
   if (m_velFromInputIn.isNew()) {
     m_velFromInputIn.read();
     if (m_velFromInput.data.length() > 2) {
       std::vector<float>  con_val = this->convert(m_velFromInput.data[0],m_velFromInput.data[1]);
       for (int i = 0; i < 2; i++)
         m_velToWheel.data[i] = con_val[i];
       m_velToWheelOut.write();
     }
   }
   return RTC::RTC_OK;
 }

This function does the following.

1. Checking if a new data is coming by using m_velFromInputIn.isNew() function.
2. Reading the data by m_velFromInputIn.read() function, if a new data is coming.
3. Converting input data to a velocity of wheels by convert() function.
4. Setting converted data to the OutPort variable, and write to OutPort buffer.

Running Build Proces

Click "Build" menu button and build the project.

Creating rtc.conf

Create new file and input the following lines in it. Copy this file to Debug and Release folders.

 corba.nameservers: localhost
 naming.formats: %n.rtc

Running Component

Starting CORBA Name Server

Before running an RT-Component, launch CORBA name server. You can find the name server launching batch file from "Start"->"Program"->"OpenRTM-aist"->"C++"->"Example"->"NameService.bat"

Running MRCConvertorComp.exe

Go to "Debug" or "Release" folder and run MRCConverter.exe.