Getting Code Running on Drones

After I got the drones running now it was time to actually write the code to solve some exercises. The goal for this week of the GSoC period was to get 1-2 applications of the drones solved using Visual Circuit.

But before I could do that, I had to get my code to run on the drones.

Running the Scripts

The way JDE Drones works is that we have a widget that allows us to control most aspects of the drone.

What we have to do is write our code in the my_solution.py file

and click on the Play Code button after takeoff of the drone to run our code.

This worked well enough for the exercises, drone_gymkhana, follow_road and drone_hangar when I tested them. However a problem arose in the exercise drone_cat_mouse. The problem was that the widget itself did not appear when the exercise was launched.

Problem and Solution

When this happened I was quite confused. Since all of my other exercises were working properly I had come to the conclusion that all of my installs were done correctly. In this case I had no idea what exactly was going wrong, I got a hint by using rostopic echo. The output consisted of topics that were pre-fixed by cat/ or mouse/, for each drone respectively.

The difference here was that each drone had the namespace prefixed to its topic. The namespace was cat/ or mouse/. When initializing the DroneWrapper() class in my_solution.py we had to pass the namespace to the class as a parameter.

# DroneWrapper(node_name, namespace)
HAL = DroneWrapper('drone','cat/') 

The above code was what I needed to get the my_solution.py file to execute.

I’m still thinking of a solution to get the widget working. One way is to go into the drone_vel_teleop class manually and set the default namespace as cat/. However this isn’t really a long term solution to the problem.

This blog will be updated if I find a way to get the widget working well. For the time being however my current method is enough to solve the exercise.

Example of Follow Road Working:

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