FLL Robot Odometry With LEGO MINDSTORMS 51515 Rotation Sensor

[@Builderdude35]

Tell me about a time where you used the motor encoders to navigate your FLL robot!

[@dluders]

I have not yet used the Robot Inventor motor encoders in a FIRST Lego League (FLL) setting, but my FLL team used the "Port View" in the EV3 brick to determine distances travelled by the robot wheels. I can see that the RI motor encoders are MUCH better. As you know, robot wheels sometimes turn at various rates (since they slip or have bent axles), so they sometimes don't drive "straight" using strict odometry-type movements. Using the built-in RI Gyro Sensor will help in making course corrections.

[@Builderdude35]

@dluders I'm excited to see what the LEGO 51515 gyro has in store with regards to PID drive-straight algorithms!

[@vizonex4316]

I’m too old for FLL but this is very interesting 🤔

[@Builderdude35]

@Vizonex you and me both! #boomers

[@vizonex4316]

@@Builderdude35 I'm 18 but yeah lol

[@dluders]

When using Lego Mindstorms robots in FLL, one should make sure that the "gear lash" inside the motors are the same on both wheels. At the FLL Base, one has to drag the robot back into position, so that the internal motor gears are meshed the same on both sides. If one does not drag the robot back into the FLL Base, when it launches the robot may suddenly cock at an unintended angle.

[@Builderdude35]

This is a fantastic piece of wisdom! I added it to my list of tutorial topics to cover as we get closer to FLL season.

[@largewallofbeans9812]

I made this turntable robot thing and it had a few gears from the motors to the wheels, but it was very easy to recalibrate the distance values. Kudos to Lego to adding that subtle but extremely useful function.

[@gibfordsrobotlab]

I had no idea about those pull down menus on the motors allowing us to select relative position. The ability to select position or relative position is a real game changer. Thanks for showing us this.

[@Builderdude35]

You're very welcome! You are absolutely correct, it is a game changer because it gives us the best of both worlds.

[@WitoEngelke]

Nice video! For the problem at 6:46 : Another simple way, especially when using gearing before the drive wheels, is to measure your robot specific configuration. Driving for a fixed amount of rotations and measuring the distance it traveled. Higher numbers of rotation result in higher accuracy. Besides that you can look into motor acceleration and how they break. With this, the movement during start and stop gets smoother and higher motor speeds can be used. Especially useful for heavy robots. Have fun building!

[@hydroworld-soontobemigrate6160]

Is there a video coming out soon on that FLL-style robot you built from the new kit? It appears to be a successor to Sirius, and now that Robot Inventor and Spike Prime are officially allowed in competition, building compact robots like that will come in handy for many of our teams.

[@zsoltbihary3347]

I would be interested in the build instruction for this prototype as well.

[@Builderdude35]

Absolutely! As you astutely noted, this is the yet-unnamed successor to Sirius made using LEGO 51515. A video debuting the new robot will come out as we get closer to the new FLL competition season. Until, then, keep your eyes peeled for more robo cameos!

[@justadude7455]

I noticed that you don't seem to use the "More Motors" and "More Movement" extensions; is this just to keep things simpler to understand? Also, one of my biggest frustrations about the new robot and software is the removal of text files - is the only solution (in terms of RLI calibration) to have all runs/programs in the same project? Or should we just have predefined RLI values?

[@Builderdude35]

Great observations! I am going to dip into the "more motors" extensions in future videos, for now I am keeping things simple. As for the calibration, I don't have a great solution for that yet, but I am hoping to have one soon! Thanks for putting it on my radar!

[@aljawwal13]

استمر يا بطل

[@Builderdude35]

Thank you! :D

[@Carbon_]

Can you use Lejos in FLL ?

[@Builderdude35]

Last I remember, they weren't allowing third party software. That may have changed, so always double-check the rules in your region!

[@Carbon_]

@@Builderdude35 I didn't saw any rules about these so maybe they are allowed now ?

[@Builderdude35]

@@Carbon_ As far as I know, FIRST's intention is to allow both Robot Inventor and Spike Prime for the upcoming FLL season. Always double-check your local rules though! :)

[@bobcubsfan]

Of course you can set multiple motors to Shortest Path with one block.

[@Builderdude35]

Good to know! Thanks for pointing that out!

[@bobcubsfan]

@@Builderdude35 In the set movement motors block can you choose just 1 motor? Also, why use Stop Movement instead of the blue block, Stop Motor?

[@Builderdude35]

@@bobcubsfan Six in one, half a dozen in another ;)