Fiducial Follow Issue (drives backwards)

1

So I ran the command to begin the Fiducial follow on the magni, however, for some reason instead of the magni driving towards me, it drives away from me.
I printed the marker to the recommended size 14cm by 14cm.
I tried to flip the marker upside down as well, but it keeps driving away instead of towards me

is that supposed to happen?

should I upload the log here?

2

Hmm if I recall correctly, the robot should maintain a fixed distance away from the marker. So if you move it too close it’ll move backwards and if you move away it’ll move closer.

Edit: Ah yes, seems like you might want to adjust these two parameters:

  # Minimum distance we want the robot to be from the fiducial
   self.min_dist = rospy.get_param("~min_dist", 0.6)

   # Maximum distance a fiducial can be away for us to attempt to follow
   self.max_dist = rospy.get_param("~max_dist", 2.5)
1 Like
3

I have one more small question, for the case of the fiducial navigation, is the magni running autonmously, i.e. avoiding obstacles in this case? or would I have to write this in?

4

I should start by saying your question is not actually a ‘small question’ unless I say just reply with the small answer of ‘no’.

the longer answer follows
At this time for fiducial nav we have just a basic package that goes from one point to another and do not ourselves have full featured nav with costmaps and object avoidance.
We have a simple package called move_basic because it is really very basic.

There is an industry standard for doing nav with costmaps and object avoidance with path re-plan and so on and it is called move_base. move_base is often used with lidar nav systems.
Make no mistake about it, it is HIGHLY tricky to use but we figure we could not do better than that so because it too is open source we point people to move_base as required.

Users of move_base combined with lidar nav are many.

I have not as of yet seen anybody get move_base to work with our fiducial nav. I know about lidar nav but am not one of our team experts on use of fiducial ceiling nav. I know of other folks who have sort of written their own path planners but that is an extremely complex and time consuming task.

5

Okay, so let me get this cleared up. For the case of having the fiducial mapping navigation. I would basically run the magni through the environment with specific instructions as to how to navigate?
i.e. let’s say I make it go in a straight line then turn right (a specific angle), and then a few steps ahead. Can I run this on a loop? if I make it start again from the same starting position? So like in a way I would have preplanned path for it to follow. Is that part of the fiducial navigation?

Edit: So, I reread the fiducials documentation, but I just still am not sure if that is what is happening?

Edit2: for the stack navigation, you guys are using move_bsae package?

6

Another note, on the original issue.

Make sure that your camera position is set-up correctly in /etc/ubiquity/robot.yaml. If the robot thinks the camera is facing upward, but you are trying to follow with a forward facing camera, the robot will do the wrong thing when it tries to calculate the follow trajectory.

Please open a new thread for the fiducial navigation stuff, we would love to answer it but mixing threads makes it difficult to find for other people in the future.

Rohan Agrawal

1 Like
7

Yesssss, I went through some of the older posts to see if my issue is similar to others, and I found your reply!! My camera positioning was actually facing upwards and not forwards.

Thank you again!! And I shall make a new thread for the fiducial Navigation

1 Like