Using Marilou Robotics Studio simulation engine with RTMaps (Tutorial 6)

Duration: 20 min.

Running the samples

Installing the tutorial files

The tutorial setup will install several files under the path <RTMaps install dir>/Tutorials/Marilou. Some files will be used by the Marilou Robotics Studio simulation engine (“resources” directory) and others are two RTMaps diagrams.

Diagram 01-simpleRoom.rtd

This world is composed of a small room and a robot named Wheely. It can be driven with the keyboard keys :

Diagram 02-fullRoom.rtd

The robot is totally driven by a very basic neural network. It moves autonomously and purposeless around the room. This diagram shows how to add image processing capabilities: this chain is able to get a click from the image viewer and detect the colour of the selected area. This colour will then be used by the BlobAnalyser component to recognize the colour in the environment.
You can find the tutorial about the BlobAnalyser by clicking here here .

Components and packages descriptions

Marilou Package

This package is specific to Marilou Robotics Studio. It contains three components:

• MarilouExec
• WheelyRobot
• Wifibot

MarilouExec

MarilouExec is responsible of the Marilou world loading. It works as if launched through the Marilou Robotics Studio menu.
To test it, first create a new empty diagram into RTMaps and register the rmaps_Marilou.pck. This package may be located into the standard RTMaps package directory.

<rtmaps install directory>/packages

Now drag and drop MarilouExec into the RTMaps workspace. MarilouExec has only one property file that specifies the Marilou Robotics Studio world to load. Click on “help” button on the window property to obtain help on this component. Set this property file to any .mdsp file. Therefore, you can use for example one of the two worlds provided by the tutorial (01-simpleRoom.mdsp or 02-fullRoom.mdsp):

<rtmaps install directory>/tutorials/Marilou/resources/
.

When you press the Run button of the RTMaps Studio, a window showing the simulation appears.

WheelyRobot

The WheelyRobot component is connected to the robot located in the Marilou world. It has three properties.

• The nbConnectionAttempts sets the number of times the component will try to connect to the Marilou simulator engine trough the exec server. In case of failure, an error message appears into the console, and the component dies. As the MarilouExec simulation and the Wheely component are in separate threads, this property is used to be sure that the MarilouExec has completly loaded the simulated environement. You should increase this number when you are using heavy worlds, or when your computer has not enough resources to load quickly the world
• The modaServer is the network name of the computer that hosts the simulator. It is set to localhost by default
• The robotName property corresponds to the name of the robot model entity in the Marilou Robotics Studio. It is the unique identifier of the robot in Marilou : it MUST be the name given into the Marilou world.

You can use the Marilou device explorer to find every the entity names known by the simulator. When the diagram containing only the MarilouExec component is running (see above), launch the program file "DevicesExplorer.exe" located into

<Marilou install diretroy>\Samples\Tools\DevicesExplorer\bin\Release

You can also open the device explorer directly from the simulation window that is running, in the tool menu, by choosing Devices Explorer.

When the device explorer is opened, you have to configure the host that is running the simulation

You will then be able to explore the structure of every loaded entity. In this example, the robot name is Wheely. This name will then be used internally to find every core devices like sonar or motor belonging to it, for instance :

/Wheely/

usFL/ray/device_sonar
hinge2/a1/motorRight

Wheely is a differential drive robot equiped with 4 SRF08 sonars sensors. The component WheelyRobot provides an access to these mecanical parts, through its inputs and outputs.

Left motor right motor

Sonars Image Encoders

WifiBot

The WifiBot component has exactly the same properties as the WheelyRobot component. But this time, the name property is set to WifiBot. The component has also different inputs and outputs as the mechanical and sensors are not the same.

Left motor right motor

InfraRed Sensors

Package Control

This package contains several useful components not specifically related to Marilou Robotics Studio:

• ARGB2RGB: This component removes the Alpha layer on a picture (its transparency). It transforms an ARGB to a RGB picture. RGB pictures without Alpha layer are needed by almost all RTMaps image processing components. Be sure that you translate Marilou pictures before using them into RTMaps.
• MappingKeys: This component translates ASCII code values of the keyboard keys (Z, S, Q and D) into integer values for the left and right motors.
• NNAvoid: This component contains a very simple multilayer perceptron neural network. It has 4 inputs, for each sensor, and 2 outputs for left and right motors. It has one hidden layer. The neural network outputs are the motors commands based on the sensor values. This allows basic obstacle avoidance.
• Odometry: estimates the robot position with the values given by left and right encoders. See more details on this component below.
  

The odometry component contains several properties that must be configured to compute the correct robot position at every step :

• startX : Starting X position of the robot at the beginning of the run.
• startY : Starting Y position of the robot at the beginning of the run.
• startAngle : Heading of the robot at the beginning of the run
• distWheels : Distance in meters between the robot's wheels
• ticsPerCycle : Odometers tics per cycle
• weelRay : Robot wheels ray
  

Contact us or leave a question in the forum.