Connecting to the exoskeleton

This tutorial will help you set up a wireless connection with the exoskeleton. If you are interested in connecting with an ethernet cable, take a look at Connecting to the exoskeleton with ethercat.

Note

Make sure your workspace is sourced and set-up correctly: Building your workspace.

Preparation before connecting

This tutorial is written to establish a connection between your computer and the exoskeleton on the same wifi. So, make sure you are on the same wifi. A public network such as eduroam will probably not work. Normally the MARCH exoskeleton automatically connects with the hotspot: MARCH.

Running commands on the exoskeleton computer (SSH)

Secure Shell (SSH) is a network protocol which allows running commands on the exoskeleton. Connect with the exoskeleton by typing ssh march@march in a terminal. Now all commands in this terminal are executed on the MARCH exoskeleton computer.

ROS Master URI

To use ros commands you need to setup the right ROS_MASTER_URI in every terminal you use:

export ROS_MASTER_URI=http://<exoskeleton_ip>:11311/

<exoskeleton ip> can be obtained by running the command hostname -I in a terminal on the exoskeleton computer. If you’re running remote/headless, it’s probably easier to SSH into the exoskeleton computer.

Instead of running this command in every terminal you open, you can do this automatically for every terminal on a computer by adding this command to your ~/.bashrc

ROS IP

To use ros commands you also need to setup the right ROS_IP in every terminal you use:

export ROS_IP=<your_ip>

<your ip> can be obtained by running the command hostname -I in a terminal on your computer.

Instead of running this command in every terminal you open, you can do this automatically for every terminal on a computer by adding this command to your ~/.bashrc

Add March network to hosts file

You need to add the march network with ip to your hosts file:

  • Type sudo nano /etc/hosts in your terminal.

  • add the line <exoskeleton_ip>       march at the top of the file.

  • Close and save the file with ctrl + x.

Test ROS on multiple devices

This is a very simple test to make sure you followed Preparation before connecting correctly.

  • Run roscore in a terminal on the MARCH exoskeleton computer (you can always do this via SSH).

  • Run rostopic list in a terminal on your computer. This command should give the output /rosout /rosout_agg

  • Run rostopic echo /march/test in a new terminal on the MARCH exoskeleton computer. This command gives a warning.

  • Now publish a message with the command rostopic pub /march/test std_msgs/String "data: 'Hello World'"

  • The message is sent and received successful if you received the message in the MARCH exoskeleton computer.