vex iq next level, reverse 4 bar

Don’t think we will compete with this one, but we wanted to build it anyway. It turned out better than we thought. Is actually a quite-nice robot.

We came back after the video was shot and added another stage of gear reduction (1:3 ratio) and now it will high hang successfully.

Nice job so far! I built one back in May, and it worked quite well. I have a few suggestions on ways you can improve it.

  1. Place the motors on the towers, rather than the middle. In VRC, the motors are placed in the middle because the metal of the bottom half weighs more than the motors, so it is beneficial. However, in VIQC, the motors way more than the plastic so you are actually lifting more weight by putting them in the middle.

  2. Rubber bands are useful if you notice your robot is struggling with lifting items, so your gear ratio wont need to be as high. The tension the rubber bands create do some of the heavy lifting for your motors. Proper use of rubber bands can allow the motors to only have to lift the hubs.

The naming of lifts can be rather confusing, so I can give you a tip on that as well.

  • Reverse means that the towers are in the front of the robot, with the arms going backwards.
  • Double means that there are two stacked on top of each other.
    Using these rules, the name of the lift is actually “Double Reverse 4 Bar”.

We put the motors in the middle because of having a more direct access to the double gear assembly. It make for a much more direct control of the lift and reduced springiness/bounce dramatically.

Lifting has not been a problem, but it would not high hang until we added another gear reduction.