Revision as of 16:25, 14 October 2012

This page describes creating a ROS/Calico connection.

ROS

ROS is the Robot Operating System. Here we assume a standard ROS install.

RosCS

RosCS is a ROS package which creates a connection between Mono and ROS. It takes a C# file and dynamically builds all of the needed links into a set of dynamic link libraries (DLL).

First, we need a local copy of ROS. We are using the current version of ROS (called "fuerte"):

1. source /opt/ros/fuerte/setup.bash
2. mkdir ~/ros
3. rosws init ~/ros /opt/ros/fuerte
4. source ~/ros/setup.bash
5. roscd

Next, we need to install the package RosCS:

1. rosws set cn-roscs-ros-pkg --git https://code.google.com/p/cn-roscs-ros-pkg/
2. source ~/ros/setup.sh
3. rosws update cn-roscs-ros-pkg
4. [remove <rosdep name="mono"> from ~/ros/cn-roscs-ros-pkg/roscs/manifest.xml]
5. rosdep install roscs

Finally, we create a C# file and build the DLLs:

1. mkdir sandbox
2. rosws set ~/ros/sandbox
3. source ~/ros/setup.sh
4. cd sandbox
5. roscreate-pkg ROS std_msgs rospy roscpp roscs
6. Create a C# file in ROS/src/hello.cs (see below)
7. Edit ROS/CMakeLists.txt to add text (see below)
8. roscd ROS
9. rosmake

If it compiles without errors, then you can copy the .dll and .so files from lib to Calico/modules/

1. cd lib
2. cp *.dll *.so ~/Calico/trunk/modules/

The next section explores using these libraries.

hello.cs:

using System;
using System.Threading;
using RosCS;

public class RosCsExample
{
    Node node;
    Publisher pub;

    public RosCsExample()
    {
	this.node = Node.MainNode;
	this.pub = new Publisher(this.node,"DummyTopic",RosCS.std_msgs.String.TypeId,1);
	this.node.Subscribe("DummyTopic",OnMessage,6);
        
    }

    public void OnMessage(RosCS.std_msgs.String msg) {
	Console.WriteLine("Got message: "+msg.Data);
    }

    public void Run() {
	int i = 0;
	while(RosSharp.Ok()) {
	    RosCS.std_msgs.String msg = new RosCS.std_msgs.String();
	    msg.Data ="Hello "+i;
	    this.pub.Send(msg);
	    i++;
	    Thread.Sleep(1000);
	}                       
    }               

    public static void Main(string[] args) {                        
	RosSharp.Init("NodeName",args);                 
	RosCsExample rce = new RosCsExample();
	rce.Run();
    }
}

Add to bottom of CMakeLists.txt:

rosbuild_include(roscs cncs)
rosbuild_gen_cs_msg()
rosbuild_gensrv()
CSHARP_ADD_TARGET_DEPENDENCY(hello Mono.C5) 
CSHARP_ADD_EXE(hello src/hello.cs)

Calico

1. In a terminal, run roscore:
   1. source ~/ros/setup.bash
   2. roscore
2. In another terminal, start Calico:
3. StartCalico
4. Run sample Python code (below)
5. In another terminal, run rostopic
6. rostopic echo DummyTopic

import System
import RosCS

# First we initialize the root (NodeName) and get the node:

RosCS.RosSharp.Init("NodeName", System.Array[str]([]))
node = RosCS.Node.MainNode

# Next, we create a publisher to post on a topic, here DummyTopic:

publisher = RosCS.Publisher(node, "DummyTopic", RosCS.std_msgs.String.TypeId, 1)

# It is setup to receive string messages

# Next, we setup a receiver callback:

def OnMessage(msg):
    ## msg is RosCS.std_msgs.String
    print("Got message: " + msg.Data);

# Directly calling the Subscribe doesn't work because signature is based on type:
# node.Subscribe("DummyTopic", OnMessage, 6)
# So, we get the overload by type:
Subscribe = node.Subscribe.Overloads[str,
                                     RosCS.OnString,
                                     int]
# and call it:

Subscribe("DummyTopic", OnMessage, 6)

# And now we start sending and receiving messages:
i = 0
while RosCS.RosSharp.Ok() and i < 10:
    # Create a string message:
    msg = RosCS.std_msgs.String()
    msg.Data = "Hello " + str(i)
    # Send it:
    publisher.Send(msg)
    # Wait for a second, and continue:
    i += 1
    System.Threading.Thread.Sleep(1000)

Issues

1. does it shutdown correctly?
2. can we package this up so that it callable from other languages?