Any ideas with height restriction?

Hello everyone, as you all know we have a height restriction that limits our robots so they cannot extend past their bumpers by 16 inches as well as vertical restriction’s. How is everyone combatting this issue, and does anyone known a good resource for coding a motor height limit in the software side of things? thanks

The easiest way to prevent your robot from overextending is to implement hard stops that physically prevent it from doing so. This will also make inspection go much easier.


Just to clarify, you can’t extend more than 16 inches past your frame perimeter, not the end of your bumpers.

  • Fair solution: implement a combination of limit switches to motor controllers and limit switches and/or encoders to software to keep from exceeding the limits. Setting motor controllers to brake mode will help, too.
  • Better solution: As @Ryan_Blue said - make it physically impossible to exceed the maximum height and frame perimeter without breaking something.
  • Best solution: Both! The limit switches and encoders and software will keep you from hitting the hard stops at speed, so you don’t break something.

In every case, test your system and make measurements BEFORE your robot inspector does!

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good to know, thank you!

Yeah, that’s what I pretty much found when it comes to software side of things. I’m still relatively new with programming so I’m not certain how to program the encoders to tell the motors to stop at a certain distance. However, it seems that a physical stop will be the better option in this instance.

Yeah, that’s I was referencing to, it just didn’t come out like that lol.

For my team’s robot, we are using pancake cylinders as a physical block to prevent the arm from extending when on the field outside the climbing area (even accidentally).
And yes, absolutely ensure you have hard stops preventing an arm from extending beyond the 16 inch frame perimeter allowance

Depending on your motor, you can use CAN position control (and tune the PIDF values) to set a max position, but keep in mind the arm can still exceed that position when stabilizing into that final value, so you definitely want to utilize soft stops (like limit switches) to avoid extending too far

sounds good, thanks for the advice

If you ever need help with coding questions, feel free to ask us here. If you’re code is in GitHub, it’s even easier, as we can look at it and make suggestions to help!

sounds good! I have not setup a GitHub for our team but it sounds like it is a good resource to use.

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