VEX Robotics

Ladder Climbing Robots (May 2024 – May 2025)

Mechanical Designer and Builder, Team 2654E Echo, VEX High Stakes

Overview 

High Stakes was the VEX Robotics game for the 2024–2025 season, in which teams scored by placing rings on stakes, moving goals into corners, and climbing a central structure at the end of the match. Climbing the center structure was by far the hardest task to complete, and only a few teams were able to do it successfully.  As the Mechanical Designer and Builder, I was responsible for the complete design of the robot and most of the fabrication and assembly. 

Key Innovations 

• Robust PTO (Power Take Off) that distributed 75% of the robot's motor power to different subsystems

• Novel lift/intake/hang system with unmatched speed and high reliability

• Passively deploying hang and passively actuating compact object manipulators

• Highly integrated construction refined over dozens of CAD models and physical robot iterations

• Cutting-edge climbing mechanism with optimized geometry to     

  • Minimize flexure and torsional deformation under combined bending and torsional loading

  • Maintain a uniform torque demand across the full range of motion

  • Reliably grab each ladder rung even with overheated motors, low air pressure, and bent components

Highlights 

• First team to achieve a sub 10 second Tier 3 elevation 

• Only team to achieve a sub 10 second Tier 3 elevation while carrying a goal (video on the right)

• Set several world records in Robot Skills including one that stood for over 3 months (longest standing record in modern VEX)

• Produced a world class 400+ page engineering notebook documenting our design progression and released it as a public resource with 1500+ unique monthly views

• Earned 19 top awards including the top judged award at the World Championships 

• Mid Season Reveal: https://youtu.be/X0uw_-r3_tI?si=QlHGsHT73cHbivv6 

Design Progression

Our first robot was built for versatility — a platform to test mechanisms and fine-tune subsystems for speed and reliability. Its centerpiece was a fully custom ring intake and scoring mechanism, named after our team and adopted widely across the competitive community, built on an offset four-bar linkage. It set a world record at our first tournament, but exposed a ceiling: we had nearly maximized what ring scoring alone could achieve, which pushed us toward developing a climber.

The second robot paired our scoring system with a Tier 3 climb. At the time of our first successful hang, fewer than five teams worldwide had managed it at all — we were the only one under 10 seconds. Iterating from 33 seconds down to 8.5, and combining the climb with scoring improvements, pushed our Skills score to 131 and demolished the world record. The complexity came at a cost: the mechanism was vulnerable to match damage, eventually failing catastrophically and forcing a redesign.

The third robot prioritized reliability over speed. The scoring mechanism was simplified, the hang geometry was revised to allow climbing while carrying a goal, and motor allocation was rebalanced toward the drivetrain and climb. It hit peak scores more consistently and translated that durability into match performance — we were consistently selected among the top three alliances at major competitions.

The fourth robot competed at the World Championships, where less than a dozen teams could perform a Tier 3 climb reliably. It was a focused refinement of the third: revised climb pivot points, improved string routing, custom-manufactured sprockets for optimal intake speed, and a repositioned arm pivot for better loading geometry. Weight was reduced and the center of mass lowered, improving overall stability. The result was a 15% faster skills route — with practice runs finishing up to 10 seconds early, deliberately slowed in competition to favor consistency.