.. role:: python(literal) A Journey to a New Simulation ============================= .. warning:: This tutorial requires a recent version of MORSE. Follow the instructions :doc:`here <../installation>` to install the latest version. .. note:: This tutorial will guide you through the development of a complete simulation, including the creation of a robot and a new actuators from scratch. Chapter Zero ------------ To start this journey, you need a working installation of MORSE. If it is not the case, refer to the :doc:`installation notes <../installation>` first, and come back after! Chapter One: The Ranger robot ----------------------------- Let's start by giving a destination to our journey: the **Ranger** robot. .. image:: ../../../media/journey_ranger/ranger_robot.jpg :align: center The **Ranger** is a robot developped at EPFL, at the `CHILI `_ and `LSRO `_ labs. The project aims at creating a nice, funny robot that would help children to tidy up their rooms. It is basically a wooden box, with two wheels, animated eyes. It can play sounds and have a large amount of LEDs on the faces. After spending some minutes in the :doc:`MORSE component library <../../components_library>`, it appears that the :doc:`../actuators/v_omega_diff_drive` may be a good candidate to control the wheels. However, for the eyes and the LEDs, we will need to create something new. But first, we want to create a 3D model for our robot. Chapter Two: Making a robot mesh -------------------------------- Creating a new robot ++++++++++++++++++++ Making a new robot model does not require anything beyond creating a 3D mesh in `Blender `_ (which also mean you can import existing meshes in a variety of format in Blender). .. note:: Creating a realistic robot model may become more complex, especially if you want/need to use :doc:`armatures <../../dev/armature_creation>` to represent complex kinematic chains, or if you want to :doc:`create low-poly bounding boxes <../tips/bounding_boxes>` for good performances when simulating collisions. In the MORSE data directory (typically, ``/usr/local/share/morse/data``), many 3D models are available that can be good starting points. In our case, ``props/crates.blend`` contains 3 models of wooden box that we can use as starting point. But first, let's create a new MORSE project. Choose a location where you would like to store your simulation, and run:: $ morse create ranger_sim This creates a new directory called ``ranger_sim``, with a file called ``default.py``, and two sub-directories: ``scripts/`` and ``src/`` (currently empty). ``scripts/`` contains a sample test client, we come back to that in chapter 3. We can straight away test our simulation:: $ morse run ranger_sim After MORSE has loaded, it should display something similar to this: .. image:: ../../../media/journey_ranger/initial_sim.jpg :align: center You can already move around the robot (*Morsy*, the MORSE mascot!) with the arrow keys, and it should create collision if you drive it to an obstacle. .. note:: You can control the camera by maintaining down the :kbd:`Ctrl` key and moving around the mouse, and with the :kbd:`WASD` keys. Let's now create our own robot model. First, ask MORSE to create for us the templates for a new robot called *ranger* inside our ``ranger_sim`` simulation:: $ morse add robot ranger ranger_sim This create several new files in ``ranger_sim/``: ``data/ranger_sim/robots/ranger.blend`` contains a default mesh for our robot, ``src/ranger_sim/robots/ranger.py`` describes the behaviour of our simulated robot (currently, it does nothing particular) and ``src/ranger_sim/builder/robots/ranger.py`` describes the equipment of the Ranger. Initially, a simple motion controller and a position sensor. To use this new robot in our simulation, open ``ranger_sim/default.py`` with your favorite editor, and replace the default robot with the *Ranger*: add :python:`from ranger_sim.builder.robots import Ranger` at the top of your file, and replace on line 15 :python:`Morsy` by :python:`Ranger`. You can also remove the lines that add the motion controller, the keyboard controller and the pose sensor since these are already part of the default equipment of our robot. The new ``default.py`` should look like that: .. code-block:: python from morse.builder import * from ranger_sim.builder.robots import Ranger robot = Ranger() robot.translate(1.0, 0.0, 0.0) robot.add_default_interface('socket') env = Environment('sandbox', fastmode = False) env.set_camera_location([10.0, -10.0, 10.0]) env.set_camera_rotation([1.05, 0, 0.78]) Run again this simulation with:: $ morse run ranger_sim You should see... no differences! The robot template created by MORSE uses the same mesh as the *Morsy* robot. We will fix that now. Editing the robot mesh in Blender +++++++++++++++++++++++++++++++++ Open the current default mesh of the *Ranger* with Blender:: $ cd ranger_sim $ blender data/ranger_sim/robots/ranger.blend Blender opens and should display the *Morsy* wireframe: .. image:: ../../../media/journey_ranger/blender_morsy.png :align: center You can press :kbd:`z` with the mouse over the 3D view to switch from the wireframe to the solid model. Now: - Select all objects (:kbd:`a`) and delete them (:kbd:`x`) - `File > Append`, then browse to MORSE ``props`` directory (typically, ``/usr/local/share/morse/data/props``), locate and select ``crates.blend`` - Click on `Group`, then `small_crate`, then validate by clicking on `Link/Append from Library` button. - If you do not see the object, check it is not on another layer: .. figure:: ../../../media/journey_ranger/layers.png :align: center Here, the object has been imported on the third layer. Click it, select everything (:kbd:`a`), then move it to first layer (:kbd:`m`), and switch back to the first layer. - Save your file, quit Blender, and relauch the simulation (``$ morse run ranger_sim``) .. image:: ../../../media/journey_ranger/crate_robot.jpg :align: center It looks better, but we can improve it even more. .. image:: ../../../media/journey_ranger/ranger-box_s.png :align: center Re-open ``ranger.blend`` in Blender and follow these steps: - Select the crate (right-click on it) - Switch to `Edit mode` (:kbd:`tab`) - Remove one by one the diagonal wood boards by selecting one vertex of the board, pressing :kbd:`l` to select the connected vertices, and finally :kbd:`x` to delete them. .. image:: ../../../media/journey_ranger/ranger_edit_1.jpg :align: center - Still in `Edit mode`, select the top face... .. image:: ../../../media/journey_ranger/ranger_edit_2.jpg :align: center - ...and extrude (:kbd:`e` followed by :kbd:`z` to constrain extrusion on the Z axis) it to create the inner of the box. .. image:: ../../../media/journey_ranger/ranger_edit_3.jpg :align: center - Create the eyes: leave `Edit mode` (:kbd:`tab`), switch to `Quad view` (menu `View > Toggle Quad View`), and place the 3D cursor where you want to place the first eye (with a left click) .. warning:: In MORSE, the X axis is the forward axis: that is not the Blender convention. You want to add eyes on the `Right Ortho` face in Blender interface. - Add a new cylinder (:kbd:`Shift + a`), rotate it by 90deg on Y axis (:kbd:`r y 90 `), and scale it (:kbd:`s`). Adjust the thickness by scaling again along the X axis (:kbd:`s x`). Name your object `right_eye` (by double-clicking it in the outliner). - Open the `Material` panel, create a new material (with the `+` button), call it `Eye`. It should be automatically assigned to your object. .. image:: ../../../media/journey_ranger/ranger_edit_3_1.jpg :align: center - With the eye selected, switch back to `Edit mode`. Select all the vertices (:kbd:`a`), and duplicate the cylinder (:kbd:`Shift + d`). Scale it down and place it to create the pupil. Open the `Material` panel. Create a new material, name it `Pupil`, change the `Diffuse` color to black, and press `Assign` to assign it to the pupil vertices. .. image:: ../../../media/journey_ranger/ranger_edit_3_bis.jpg :align: center - Leave the `Edit mode` and apply the scale transformation: :kbd:`Ctrl + a`, then `Scale`. Duplicate the eye (:kbd:`Shift + d`) and move it along the Y axis (:kbd:`g y`). .. image:: ../../../media/journey_ranger/ranger_edit_5.jpg :align: center Save you file, quit Blender and run your simulation: that should be enough to start playing a bit around! .. image:: ../../../media/journey_ranger/ranger_sim_1.jpg :align: center In the next chapter, we'll see how to control the movement of the robot from an external application (your robot controller), and in the following chapter, we will try to move the eyes (we will have to create a new dedicated actuator to this end). Chapter Three: Our first robot controller ----------------------------------------- MORSE is all about integrating simulation as transparently as possible in your usual workflow: we want you to be able to switch almost transparently from a real robot to the simulated robot. To achieve that, MORSE relies on intermediate *middlewares*, like ROS, YARP, etc. You can get an idea of which features of each middlewares are supported by MORSE `on this page `_. Sometimes, for quick prototyping, or simply to evaluate what is actually possible to simulate, you do not want to use a full middleware, but a more lightweight interface. MORSE comes with a simple socket-based interface for that purpose, and also a simple-to-use Python binding that will enable us to quickly test our robot controller. Moving the robot ++++++++++++++++ Let write a first test right away. Open your favorite editor and copy-paste this example: .. code-block:: python :linenos: from pymorse import Morse print("Use WASD to control the Ranger") with Morse() as simu: motion = simu.robot.motion v = 0.0 w = 0.0 while True: key = input("WASD?") if key.lower() == "w": v += 0.1 elif key.lower() == "s": v -= 0.1 elif key.lower() == "a": w += 0.1 elif key.lower() == "d": w -= 0.1 else: continue motion.publish({"v": v, "w": w}) Save it somewhere (for instance, as ``ranger_sim/scripts/keyboard_ctrl.py``), launch the simulation (``$ morse run ranger_sim``) and run your script:: $ morse run ranger_sim & $ python3 ranger_sim/scripts/keyboard_ctrl.py .. note:: A client script, very similar to this one, is automatically generated when creating the simulation environment. You will find it under ``scripts/ranger_sim_client.py``. .. warning:: ``pymorse`` the Python bindings for MORSE, require Python 3 Press :kbd:`Ctrl + c` to interrupt the ``keyboard_ctrl.py`` script, and let examine the detail of this first example. On line 1, we import the ``pymorse`` bindings. To use them, we create on line 5 a *context*: at creation, the connection is established with the simulator (by default, on ``localhost``, but you can `change that `_), and when we exit the context, the connections are properly closed. In this example, the context object is stored in the ``simu`` variable. On line 7, we retrieve the motion controller *end-point*. The names to access it is the same as the way we named our components in the simulation script (``default.py`` and ``ranger.py``). .. note:: Here, in ``default.py``, on line 5, we called our robot ``robot`` by simply naming that way the ``Ranger()`` object: .. code-block:: python :linenos: from morse.builder import * from robots import Ranger robot = Ranger() # The list of the main methods to manipulate your components # is here: http://www.openrobots.org/morse/doc/stable/user/builder_overview.html robot.translate(1.0, 0.0, 0.0) [...] If you check ``src/ranger_sim/builder/robots/ranger.py``, you will find out that the Ranger's motion controller has been called ``motion``. So with ``pymorse``, we access the motion controller simply as :python:`simu.robot.motion`. Then, at line 12, we start the main loop: we read a keyboard input, we change the linear ``v`` and radial ``w`` speeds depending on the user input, and, line 26, we send to the simulator the new command. The command is a plain Python dictionary, whose content depends on the actuator. In our case, we are using a ``MotionVW`` actuator (see ``src/ranger_sim/builder/robots/ranger.py``). The :doc:`documentation of the component <../actuators/v_omega>` tells us what the actuator expects. Accessing sensors +++++++++++++++++ ``motion`` is an actuator. If you open ``robots/ranger.py``, you will see the template also declare a :doc:`Pose sensor <../sensors/pose>`. We can access it to print the current position of the robot. Open ``scripts/keyboard_ctrl.py`` and modify it that way: .. code-block:: python :linenos: from pymorse import Morse def pose_received(pose): print("The Ranger is currently at %s" % pose) print("Use WASD to control the Ranger") with Morse() as simu: simu.robot.pose.subscribe(pose_received) motion = simu.robot.motion v = 0.0 w = 0.0 while True: key = input("WASD?") if key.lower() == "w": v += 0.1 elif key.lower() == "s": v -= 0.1 elif key.lower() == "a": w += 0.1 elif key.lower() == "d": w -= 0.1 else: continue motion.publish({"v": v, "w": w}) Restart the ``scripts/keyboard_ctrl.py`` script:: $ python3 ranger_sim/scripts/keyboard_ctrl.py It should start quickly filling your console with the position of the robot. You can still control it with :kbd:`WASD` as you did previously, and you should see the position values changing. Chapter Four: Creating a new actuator to move the eyes ------------------------------------------------------ A First Skeleton ++++++++++++++++ Let now create a new custom actuator for the eyes of our robot. - Add a new actuator template called ``eyes`` to the ``ranger_sim`` simulation:: $ morse add actuator eyes ranger_sim MORSE asks you for a short description of your actuator (enter something like "*Controls the eyes of the EPFL Ranger robot*") , and then create a new set of templates: ``src/actuators/eyes.py`` defines the behaviour of the actuator (how the actuator interacts with the simulation) and ``src/builder/actuators/eyes.py`` provides the *Builder API* interface to use the actuator in simulation scripts. .. note:: Contrary to robots, where you are encouraged to modify their *Builder API* to define the robot equipment, you usually do not need to change it for actuators (or sensors). The only case where it may be useful is to specify a special 3D mesh for your component (like the casing of a laser scanner, etc.) The default actuator template does not provide any useful behaviour, but it can already be added to our robot: - Open ``src/ranger_sim/builder/robots/ranger.py``, and add this ``import`` statement: .. code-block:: python from ranger_sim.builder.actuators import Eyes and these two lines after the motion controller: .. code-block:: python self.eyes = Eyes() self.append(self.eyes) If you launch the simulation now, MORSE will list the components available on our robot, including the eyes:: [...] [ 0.283] ------------------------------------ [ 0.284] - SIMULATION SUMMARY - [ 0.284] ------------------------------------ [ 0.284] Robots in the simulation: [ 0.284] ROBOT: 'robot' [ 0.284] - Component: 'robot.pose' [ 0.285] - Component: 'robot.keyboard' [ 0.285] - Component: 'robot.eyes' [ 0.285] - Component: 'robot.motion' [...] Moving the eyes +++++++++++++++ For our actuator to produce something tangible, we need to complete its definition. Open ``src/ranger_sim/actuators/eyes.py``, and update its content to match the following Python script: .. code-block:: python :linenos: import logging; logger = logging.getLogger("morse." + __name__) from morse.core.actuator import Actuator from morse.helpers.components import add_data from morse.core import mathutils class Eyes(Actuator): _name = "Eyes" _short_desc = "Controls the eyes of the EPFL Ranger robot" add_data('left', 0.1, 'float', 'Left eye rotation, in radians') add_data('right', -0.1, 'float', 'Right eye rotation, in radians') def __init__(self, obj, parent=None): logger.info("%s initialization" % obj.name) # Call the constructor of the parent class Actuator.__init__(self, obj, parent) self.left_eye = parent.bge_object.children["left_eye"] self.right_eye = parent.bge_object.children["right_eye"] logger.info('Component initialized') def default_action(self): l_orientation = mathutils.Euler([self.local_data['left'], 0.0, 0.0]) self.left_eye.orientation = l_orientation.to_matrix() r_orientation = mathutils.Euler([self.local_data['right'], 0.0, 0.0]) self.right_eye.orientation = r_orientation.to_matrix() Let's explain this script: .. code-block:: python class Eyes(Actuator): _name = "Eyes" _short_desc = "Controls the eyes of the EPFL Ranger robot" When creating a component, always provide a name and short description. These are used to generate the component documentation for instance. .. code-block:: python add_data('left', 0.1, 'float', 'Left eye rotation, in radians') add_data('right', -0.1, 'float', 'Right eye rotation, in radians') These two lines define the *data interface* of our actuator. For the eyes, we need to provide to the actuator two angles, one per eye. We first set the name of the data field, then its default value, its type and a short description. The data set by the simulator clients can be later accessed through the ``local_data`` dictionary (see below). .. code-block:: python def __init__(self, obj, parent=None): logger.info("%s initialization" % obj.name) # Call the constructor of the parent class Actuator.__init__(self, obj, parent) self.left_eye = parent.bge_object.children["left_eye"] self.right_eye = parent.bge_object.children["right_eye"] logger.info('Component initialized') The class constructor has nothing special. :python:`self.left_eye` and :python:`self.right_eye` are set to point to the Blender objects for the eyes (``parent`` is the robot body, ``parent.bge_object`` represents the Blender mesh of the robot body, ``parent.bge_object.children`` contains all children of the robot mesh). .. code-block:: python def default_action(self): l_orientation = mathutils.Euler([self.local_data['left'], 0.0, 0.0]) self.left_eye.orientation = l_orientation.to_matrix() r_orientation = mathutils.Euler([self.local_data['right'], 0.0, 0.0]) self.right_eye.orientation = r_orientation.to_matrix() :python:`default_action()` is the most important method of a component. It is called at each simulation step. The behaviour of the actuator is implemented here. For our eyes, we simply apply a rotation along the ``X`` axis (Blender uses rotation matrices., so we first create the rotation matrix from a vector of Euler angles). To test the eyes, we must complete our test client. Re-open ``scripts/keyboard_ctrl.py``, and update it this way: .. code-block:: python from pymorse import Morse print("Use WASD to control the Ranger") with Morse() as simu: motion = simu.robot.motion eyes = simu.robot.eyes v = 0.0 w = 0.0 left = 0.0 right = 0.0 while True: key = input("WASD (eyes:RFTG)?") if key.lower() == "w": v += 0.1 elif key.lower() == "s": v -= 0.1 elif key.lower() == "a": w += 0.1 elif key.lower() == "d": w -= 0.1 elif key.lower() == "r": left += 0.1 elif key.lower() == "f": left -= 0.1 elif key.lower() == "t": right += 0.1 elif key.lower() == "g": right -= 0.1 else: continue motion.publish({"v": v, "w": w}) eyes.publish({"left": left, "right": right}) Besides ``(v, ω)``, we now also publish on the ``eyes`` channel a pair ``(left, right)``. Run the simulation and launch your client:: $ morse run ranger_sim & $ python3 ranger_sim/scripts/keyboard_ctrl.py You should now be able to move the eyes: .. raw:: html Chapter Five - The simulation environment ----------------------------------------- To be done! Chapter Six - Creating an advanced actuator: the LED arrays ----------------------------------------------------------- To be done!