LemLib - AMA and Feedback

VEX V5 General Discussion
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Hi! I’m Liam, the founder and lead developer of LemLib, a library for autonomous motion in VRC. I’d love to hear any feedback, answer all your questions, and discuss some things regarding the spirit of the competition.

Ask me Anything

By anything I mean anything relating to LemLib, VRC, or my experience in robotics

Feedback

Anything you’d like to see in a future version of LemLib, anything you want changed. The more specific the better!

Spirit of the Game

There are concerns about libraries and their effect on the competition. The biggest concern I know of is that team’s performance in autonomous may not reflect their knowledge of the concepts. I want to hear what you all think, and what could be done to address this to ensure that VRC stays a student-centered competition.

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If I want to use an orthogonal encoder (a vertical and a horizontal one), will it affect the positioning algorithm?

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Are you still on a vex or vex U team?
did you make lemlib while on a vex team or after?

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I’m not on a VRC team or VEXU team currently, although I do meet the requirements to be part of a VRC team. I can’t be on a VEXU team because I have not graduated high school yet. I expect to join QUEEN next season however.

I wrote versions 0.1.0 to 0.4.7 while on a VRC team (1010N), all the v0.5 beta versions I made in my senior year, in collaboration with mostly other VRC students.

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it will affect the algorithm. If you have no vertical tracking wheel, LemLib would use motor encoders instead. If you have no horizontal tracking wheel, LemLib will assume there is never any horizontal movement

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wait u were on a ten ton team?

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I was in the ten ton robotics organization yea

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@LemFromTheLib, is LemLib programmed for X drives?

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No, and it’s not planned either.

The reason for this is because holonomic drive has not been viable since pneumatics were made legal in Tipping Point. If its popular enough we’ll support X-drive. I can rant about why it’s no longer popular but thats a different topic

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We have a small problem with our drive as the motor ports are right as we checked with a different program on VS code. For some reason we try to reverse the motors but when we upload the code it doesn’t change anything PLS HALP

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we have made it work but when we tried pure pursuit i just goes past the first point and just hits the wall

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I had a similar problem: what caused it for me was that the code doesn’t actually upload unless you save it first. I would use some sort of debug message just to make sure the code properly uploaded.

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Hey Liam, does LemLib require tracking wheels? My school doesn’t have any encoders, we just have IMU and I was wondering if I could still implement LemLib on our robot. Thanks

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Nope! Just set the sensors function for all of the tracking wheels to nullptr and you should be good to go.
lemlib::OdomSensors sensors(nullptr,nullptr,nullptr,nullptr,&imu);

https://lemlib.readthedocs.io/en/stable/tutorials/2_configuration.html

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Thanks!
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Hi My team is just considering moving over from easy template to LemLib We couldnt find any info about this but does lemlib have a built in auto selector like easy template? thanx

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No lemlib does not have a built in selector, but my team found another library called robodash (which is a library focused on selectors and using the brain screen easier) and figured out how to make the two work with each other.