Butterfly DT

Final CAD & RendersThe CAD and wiring are now fully finished, and I made a few final renders to show off the completed design. I wanted the renders to highlight the overall packaging and especially the butterfly pod, so you can see how all of the reductions, linkages, hubs, and wiring fit together.I also wanted to highlight the dead-axle hub. Unlike a live axle, the dead axle stays fixed while the wheel rotates around it on bearings. This lets the axle focus on supporting the wheel while the belt system handles the power transmission, making the hub simpler, more rigid, and easier to fit within the tight packaging.Looking back at the different iterations, the butterfly pod changed the most. It went from a simple gear-driven concept to a compact, belt-driven, double-sided system with a custom dead-axle hub that is much more robust and better suited to the final packaging.Overall, the final DT is quieter, more compact, more robust, and much more refined than the original design.

Butter Fly DT: Final Design After a lot of testing, redesigning, and troubleshooting, I’ve finally finished the DT design. This ended up being a much bigger redesign than I originally expected, especially with the butterfly pod. Almost every part of the pod went through multiple iterations to solve packaging, efficiency, strength, and center-to-center issues. The butterfly pod went through some of the biggest changes in the entire DT. I originally experimented with a gear-based reduction and linkage system, but after testing it, I decided gears weren’t the right solution. They added unnecessary noise, were less efficient, and made packaging much harder. The final design now uses belts for both reductions, including the butterfly mechanism. This made the system quieter, more efficient, and much easier to fit into the limited space. I also completely redesigned the butterfly linkage. Instead of using a single-sided linkage, I designed a double-sided linkage system that supports the mechanism from both sides. This makes the pod much more rigid and robust while reducing unwanted movement. Another major change was the wheel system. I moved away from using a COTS wheel and instead designed the wheel around a custom silicone-molded tire. This gave me more control over the geometry and let me integrate the wheel much better with the rest of the pod.The hub and mounting system were also redesigned from the ground up. I designed my own dead-axle hubs and reworked the surrounding structure so everything could fit within the extremely tight packaging constraints. One of the biggest challenges was getting everything to fit within 56 mm of thickness on each side. This forced me to rethink the position and configuration of almost every component in the pod. I also moved several components lower toward the ground to improve the center of gravity and overall stability. Once I worked through all the issues with the master sketch, the rest of the design became a process of slowly building everything back up, part by part. Because of all the belt center-to-center issues, I ended up redesigning almost every part and subassembly configuration. The CAD and wiring are now fully finished, and I’ve also made several renders of the completed DT. Looking back at all the iterations, the butterfly pod has probably changed the most. It went from a much simpler gear-driven concept to a compact, belt-driven, double-sided system that is much more robust and better suited to the final packaging. Overall, the final DT is quieter, more compact, more robust, and much more refined than the original design.

Just some basic changes to the master sketch upon further review it seems there are bigger issues most likely require deeper revision. It all stems from changing the motor diameter it changes center to center distances in the belts as well causes a whole slew of issues.

The physical butterfly module is fully assembled. While FTC Team 26000 used a different wheel layout, this design places one larger wheel in the center of the module. This configuration centers the 104mm mecanum wheel and uses the GT2 belt reduction to link it to the first stage, maintaining a balanced center of mass.Master Sketch CompletionThe master sketch for both the main chassis and the butterfly module is finished. Mapping all geometry in a single master sketch ensured that the 96.24269 mm center-to-center distance for the 20T and 28T pulleys aligns precisely with the packaging constraints of the 8:1 gear reduction stage. This layout locks in the axle positions and gear mesh clearances before manufacturing the final plates.Next Steps: Efficiency and AssemblyWith the core architecture defined, the focus shifts to two main areas:Mechanical Efficiency: Optimizing the module pivots and belt alignment to minimize friction losses from the 5000 RPM motor. This includes pocketing parts to remove unnecessary material weight.Connected Assembly: Finalizing the top-level assembly in CAD to verify clearances for the deployment mechanisms, electronics, and structural brackets across the full chassis.Oh also cool aside this should put me as # today in hackclub hours!

Butterfly Drivetrain DevelopmentThe butterfly drivetrain, or “switch-drive,” is a configuration that allows a robot to switch between two different types of locomotion. In my current build, I use this to alternate between high-traction movement, using 72mm hogback wheels, and omnidirectional maneuvering, using mecanum wheels.My design features a two-stage reduction system. The first stage uses an 8:1 gear reduction to power the hogback wheels directly. The second stage uses a GT2 belt system to further reduce the speed for the mecanum wheels. This ensures both wheel sets maintain consistent surface speeds despite their different diameters.Inspiration: FTC Team 26000My implementation of this system is heavily inspired by FTC team 26000. Their work on the butterfly drivetrain showcases a clean, efficient way to package two distinct movement systems within a compact chassis. I studied their design to understand how they optimized the mechanical linkages for deploying the secondary wheels. This helped me solve the challenge of integrating a 5000 RPM motor with the high torque required for a multi-wheel system.By applying these concepts to my own robot, I am building a versatile drivetrain that adapts to different match conditions while maintaining precise control over wheel speed and grip force.