*me quering a knowledge system for a pose and quaternion*
System: here is the quaternion in w x y z format
me: but for using it I need it in x y z w
System: not my problem
me: ok, fine. here is a function that flips this, np.

*months later*
me: wtf why does grasping don't work anymore? The poses look reasonable.
*after hours of trying to debug it*
*remembers hearing someone say something about finally using one standard for quaternions across the systems*
me: wait... could this be... *comments out flip function*
me: yep... that's it.
...
Overall, this is an improvement. But I lost several nerves and hours yesterday night wondering why my grasping doesn't work anymore. Feeling embarrassed, that I didn't finish my stuff in time because of this bug.
*sigh*
goddammit

ah, that instinct of commenting out some what-looks-like-its-a-working-piece-of-code and seeing that it unblocks everything, narrows down the search of the bug :)

too bad it's too late though

Oh lord the number of times this happens in animation systems and computer graphics.

I just refractored out my linear algebra stuff into a nice library. I've standardised it. This is never going to happen again. Never.

Until the next project, that is, lel

@RememberMe in case of robotics, fun things happen in these cases. Either weird error messages or the robot turns his joints funny. The later one is more fun ;D

@hasu even more fun when the PID controller goes mad and the robot runs over somebody's foot. With metal geared wheels.
Or when the controller goes mad and a very powerful fan with carbon fiber blades suddenly swings right at your face :p (thankfully the controller wasn't completely bonkers, it righted itself).

Yeah, we had a bit of a Murphy's law kinda thing going on in college.

@RememberMe LOL Oh my.

We have a wireless emergency switch, and one person is supposed to be on it at all times, therefore nothing crazy like this happens, since as soon as we even see a slight sign of something going wrong, we switch off the motors power.

The hands of the robot have a super fancy spring mechanism so that they will give in, and it cannot hurt you. He is also quite weak, 1.5kg force per arm. So it's sort of safe :)

Driving on foot would be a problem, but usually nobody is in the area when the robot moves.

Well, we also have to really be careful with it. Only 42 or 45 or so exist of them worldwide, the company that made them kinda doesn't exist anymore, so yeah. So getting replacement parts is a pain.

If you want to check out what kind of robot this is, google Willow Garage PR2 :)

I think my highlight was having the big robot and a small one listening to the same movement velocity topic. So when I tried to move the small one, the big one moved along with it. It took me a while to realize what happened and I've got the scare of my life.

It gently hit a table.

Nothing happened to it.

We just got scared af.

Now, since it was my fault, I'm fairly familiar with how to have multiple robots on the same roscore and them sharing a master without anything going wrong. xD Lesson Learned.