AM14U3 Kit Chassis Testing Over Defenses

Greetings FIRST Stronghold goers!

My name is Jason, I am a Mechanical Design Intern at AndyMark, a Junior at Purdue University, Team member on Ri3d Team Indiana and a Mentor for FRC team 4272, MBR.

I have been doing a lot of testing with the AM14U3 Kit Chassis and Rhino Tank Drive in various configurations and driving them over the defenses.

See the video of all of our testing here

There are 4 setups we tested:

  • Long Chassis with front wedge and 6" HiGrip Wheels
  • Long Chassis with front wedge and 8" Plaction Wheels
  • Wide Chassis with front and back wedges and 6" HiGrip Wheels
  • Wide Chassis with exposed 8" Plaction Wheels (no wedge)

We tested with a variety of weights and weight distributions. The long Chassis was 61 lbs and the Wide Chassis was 58 lbs. We tested them without weights as well as with 45 pounds added to both configurations.

(The wedge that we used was a 45 degrees cut 4x4 that extended the length of the front plate.)

Here are some general observations:

The configurations with the 6" wheels had a tougher time with the moat. Surprisingly the long configuration was easier to coax over the moat than the wide. The wedge is essential to navigating any of the b and d category defenses with a 6" wheel configuration.

The 8" wheels long had a decent success rate over the moat but would always beach itself on the rock wall. Even though it had good traction and contact on all 6 wheels, it would stall out the CIM’s in the Toughbox mini. The 8" wide with exposed Plaction wheels had no trouble with any of the defenses.

When the weight distribution is uniform the robot actually has a harder time getting over the defenses. Weighing the front or back more makes the traverses easier. Direction of the traverse does not matter.

Chassis flex seemed to help the robot as well. The more the chassis could conform, the easier it could wiggle it’s way out of tough spots. (Shouldn’t be a problem if your chassis has an intake/open back or front)

None of the wheels cracked or chipped during our testing, but the wood on the defenses sure took a toll. Tread showed normal signs of wear and tear. I will be testing the wheels on metal defenses soon.

The Rhino Tank Drive eats the defenses for breakfast.

I am in the process of building the 8 Wheel Drive AM14U3 with 6" Wheels to test on the defenses. If there are any additional configurations or tests teams would like me to conduct, feel free to post in this thread or direct message me. I have access to all of the defenses, the AM14U3 Chassis, most AndyMark Wheels and Rhino Track Drive.

Good Luck to all the teams out there and shout out to Team 192, GRT!


  • Jason

Nice work Jason, and thanks for including success and failures.