Tutorial 3: Inserting a Robot

Here we will learn how the process of adding a robot into a Gazebo world works.

Step 1: Loading a Robot

1. Withing the project root create an empty file tutorial3.py.
2. Make sure it is executable:

   sudo chmod +x tutorial3.py

3. Open the file with a text editor, add this piece of code to the script and save it

   #!/usr/bin/env python3
   
   import os
   import sys
   import asyncio
   from pyrevolve.SDF.math import Vector3
   from pyrevolve import revolve_bot, parser
   from pyrevolve.tol.manage import World
   from pyrevolve.util.supervisor.supervisor_multi import DynamicSimSupervisor
   from pyrevolve.evolution import fitness
   
   
   async def run():
       """
       The main coroutine, which is started below.
       """
       robot_file_path = "experiments/examples/yaml/spider.yaml"
   
       # Parse command line / file input arguments
       settings = parser.parse_args()
   
       # Start Simulator
       if settings.simulator_cmd != 'debug':
           simulator_supervisor = DynamicSimSupervisor(
               world_file=settings.world,
               simulator_cmd=settings.simulator_cmd,
               simulator_args=["--verbose"],
               plugins_dir_path=os.path.join('.', 'build', 'lib'),
               models_dir_path=os.path.join('.', 'models'),
               simulator_name='gazebo'
           )
           await simulator_supervisor.launch_simulator(port=settings.port_start)
           await asyncio.sleep(0.1)
   
       # Load a robot from yaml
       robot = revolve_bot.RevolveBot()
       robot.load_file(robot_file_path)
       robot.update_substrate()
       # robot._brain = BrainRLPowerSplines()
   
       # Connect to the simulator and pause
       connection = await World.create(settings, world_address=('127.0.0.1', settings.port_start))
       await asyncio.sleep(1)
   
       # Starts the simulation
       await connection.pause(False)
   
       # Insert the robot in the simulator
       robot_manager = await connection.insert_robot(robot, Vector3(0, 0, settings.z_start))
   
       # Start a run loop to do some stuff
       while True:
           # Print robot fitness every second
           status = 'dead' if robot_manager.dead else 'alive'
           print(f"Robot fitness ({status}) is: {fitness.displacement(robot_manager, robot)} \n")
           await asyncio.sleep(1.0)

NOTE: When the virtual environment is activated, you will see (.venv) designation appearing on the active line within your terminal window. Revolve works within this environment in order to keep your installed Python isolated from unexpected changes. Otherwise, if you feel proficient enough, you can install Revolve as part of your system. For now, we will show examples from the virtual environment.

4. Run the script:

   (.venv) ./revolve.py --simulator-cmd=gazebo --manager tutorial3.py

You should get an output like this (the robot in the picture should be different):

```
[2019-09-19 16:18:25,502     gazebo] INFO     Created Supervisor with:
	- simulator command: gazebo ['--verbose']
	- world file: worlds/plane.world
	- GAZEBO_PLUGIN_PATH: /Users/tarigarma/revolve/build/lib
	- GAZEBO_MODEL_PATH: /Users/tarigarma/revolve/models
[2019-09-19 16:18:25,502     gazebo] INFO     Launching the simulator...
[2019-09-19 16:18:26,648     gazebo] INFO     [starting] [Msg] Waiting for master.
[2019-09-19 16:18:26,649     gazebo] INFO     [Msg] Connected to gazebo master @ http://127.0.0.1:11345
[2019-09-19 16:18:26,649     gazebo] INFO     [Msg] Publicized address: 10.3.0.112
[2019-09-19 16:18:26,650     gazebo] INFO     World plugin loaded.
[2019-09-19 16:18:26,650     gazebo] ERROR    Gazebo multi-robot simulator, version 9.7.0
[2019-09-19 16:18:26,650     gazebo] ERROR    Copyright (C) 2012 Open Source Robotics Foundation.
[2019-09-19 16:18:26,650     gazebo] ERROR    Released under the Apache 2 License.
[2019-09-19 16:18:26,650     gazebo] ERROR    http://gazebosim.org
[2019-09-19 16:18:26,650     gazebo] ERROR    
[2019-09-19 16:18:26,650     gazebo] ERROR    Gazebo multi-robot simulator, version 9.7.0
[2019-09-19 16:18:26,650     gazebo] ERROR    Copyright (C) 2012 Open Source Robotics Foundation.
[2019-09-19 16:18:26,651     gazebo] ERROR    Released under the Apache 2 License.
[2019-09-19 16:18:26,651     gazebo] ERROR    http://gazebosim.org
[2019-09-19 16:18:26,651     gazebo] ERROR    
[2019-09-19 16:18:26,835     gazebo] INFO     Setting robot state update frequency to 5.
[2019-09-19 16:18:26,879     gazebo] ERROR    [Wrn] [Publisher.cc:141] Queue limit reached for topic     /gazebo/default/physics/contacts, deleting message. This warning is printed only once.
[2019-09-19 16:18:27,836    revolve] INFO     Resuming the world.
[2019-09-19 16:18:28,051     gazebo] INFO     Processing insert model request ID `168952315`.
[2019-09-19 16:18:28,450     gazebo] INFO     Model `example_spider` inserted, world now contains 1 models.
[2019-09-19 16:18:28,455    revolve] INFO     Registering robot example_spider.
Robot fitness (alive) is: 0.0 

Robot fitness (alive) is: 0.0018332006229095654 

Robot fitness (alive) is: 0.003082761382303827 

Robot fitness (alive) is: 0.005511332102695145 

Robot fitness (alive) is: 0.0029905039980699538 

Robot fitness (alive) is: 0.005352756534245831 


```